Reactivity Diversification - Synthesis and Exchange Reactions of Cobalt and Iron 2-Alkenylpyridine/-pyrazine Complexes Obtained by Vinylic C(sp2)-H Activation

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DOI:10.1002/ejic.201500225

Reactivity Diversification – Synthesis and Exchange

Reactions of Cobalt and Iron 2-Alkenylpyridine/-pyrazine

2

Complexes Obtained by Vinylic C(sp )–H Activation

[

a]

[a]

[b]

Robert Beck,* Sebnem Camadanli, Ulrich Flörke, and

Hans-Friedrich Klein^[

a]

Keywords: C–H activation / Cyclometalation / Cobalt / Iron / Nitrogen heterocycles

The reactivity of 2-alkenylpyridine derivatives with trimeth-

ylphosphane-supported iron– and cobalt–methyl adducts

were investigated and provided a series of C,N-cyclo-

ylquinoline (reductive elimination of C

a low-valent Fe(PMe

2

H

6

), which afforded

4

3

)

3

moiety bound in an η -fashion with

the exocyclic vinyl group and the ortho-carbon atoms to give

2

4

metalated complexes through smooth vinyl C(sp )–H acti-

9 6 2 3 3

(κ ,η -C,C,C,C-C H N–CH=CH )Fe(PMe ) (9). In polar sol-

3 3 4

vation. The reactions of Co(CH )(PMe ) with 2-vinylpyr- vents, an equilibrium of cyclometalated 7,8-benzoquinoline

idine, 2-(1-phenylvinyl)pyridine, and 2-vinylpyrazine pro-

exists between the mer-trans (90%) and mer-cis (10%) con-

2

vided dark green crystals of the five-membered metall-

figurations of (κ -C,N-C13

ance with the previously reported bicyclometalation of 2-(2-

= H). The oxi- naphthalene-1-ylvinyl)pyridine with iron adducts, similar re-

actions with methylcobalt species provided the monocyclo-

6 3 3 3

H N)Fe(CH )(PMe ) (10). At vari-

2

acycles (κ -C,N-R

1

R

2

C=CH)Co(PMe

= Ph; 3: R = C

3

)

3

(1: R

1 5 4 2

= C H N, R =

H; 2: R

1

= C

5

H

4

N, R

2

1

4

H

3

N

2

,R

2

dative addition of 1–3 with iodomethane afforded the mer-

2

1

3

2

trans trivalent cobalt complexes (κ -C,N-R

CH )I(PMe (4: R = C N, R = H; 5: R = C

Ph; 6: R = C , R = H) in modest yields. The reaction of

with an additional equivalent of 2-(1-phenylvinyl)pyridine

1

R

2

C=CH)Co-

metalated η ,σ -bound coordination motif (κ ,η -C,C,N-

N–CH=CH–C10 )Co(PMe (11). The reaction of 11

with carbon monoxide provided the monocarbonyl complex

(

3

)

2

1

5

H

4

2

1

5

H

4

N, R

2

=

C

5

H

4

H

6

3 2

)

1

4

H

3

N

2

3

2

(κ ,η -C,C,C-C

5

H

4

N–CH=CH–C10

H

6

)Co(CO)(PMe

3

)

2

(12),

2

incorporated a second C,N metallacycle with an η -bonded

accompanied by the release of the N-coordination site. The

2

3

2

3

alkenyl moiety to provide (κ -C,N-C

C,C,N-C N–CH=CH )Co(PMe ) (7). No cyclometalation

was observed with 8-vinylquinoline and Co(CH )(PMe

)Co(CH

group; therefore,

a suitable bite angle is required for C–H activation. No N

5

H

4

N–CH=CH)(κ ,η -

carbonylation of (κ -C,C,N-C

resulted in the exchange of one PMe

tion of the coordination sites to generate (κ -C,C,N-C

CH=C–C10 )Fe(CO)(PMe (13). All new compounds were

5

H

4

N–CH=C–C10

6 3 3

H )Fe(PMe )

5

H

4

2

3

ligand with the reten-

3

)

4

,

5 4

H N–

3

2

which afforded (κ ,η -C,C,N-C

PMe (8) with retention of the Co–CH

9

H

6

N–CH=CH

2

3

)-

H

6

3 2

)

(

3

)

2

3

identified by NMR spectroscopy and structurally charac-

terized by single-crystal X-ray crystallography (with the ex-

ception of 10 and 13).

3 2 3 4

coordination was observed with Fe(CH ) (PMe ) and 8-vin-

Introduction

cently, cyclometalated 2-phenylpyridine derivatives of Pt

and Ir showed unique features as white organic light-

emitting diodes (WOLEDs) for future flat-panel display

Cyclometalation reactions through C–H bond acti-

[

1]

vation attract a great deal of interest owing to their rele-

vance to the selective activation and functionalization of

hydrocarbons and their applications in homogeneous catal-

[8]

technologies. Remarkably, little information is available

about the reactive intermediates that facilitate the catalytic

transformations of vinylpyridine derivatives in reactions

[

2]

ysis. In particular, remarkable progress has been shown

[9]

that proceed through putative metallacycles. Our main

[3]

recently for cobalt-catalyzed transformations. Cyclomet-

alated compounds have also found numerous applications

focus on cyclometalated cobalt and iron chemistry is the

[

4]

relatively low cost of these compounds compared with

[

5]

in several fields such as organometallic synthesis, biolo-

[10]

those of their heavy congeners, Ru and Rh,

which pro-

gically active compounds,^[and materials science. Re-

6]

[7]

vides an impetus for their utilization in catalytic or stoichio-

[

11]

metric transformations.

Therefore, we develop new syn-

[

a] Eduard-Zintl-Institut für Anorganische und Physikalische

Chemie, Technische Universität Darmstadt,

theses and strategies involving electron-rich, trimethyl-

phosphane-supported methylcobalt and -iron complexes,

which we have recently found to be active in C–H bond

Alarich-Weiss-Straße 12, 64287 Darmstadt, Germany

E-mail: metallacycle@gmail.com

http://www.chemie.tu-darmstadt.de/ac/eduardzintlinstitut_1/

anorganischechemie/anorganischechemie.de.jsp

b] Anorganische und Analytische Chemie, Universität Paderborn,

Warburger Straße 100, 33098 Paderborn, Germany

Supporting information for this article is available on the

WWW under http://dx.doi.org/10.1002/ejic.201500225.

[

12]

activation reactions.

CoMe(PMe₃)₄and FeMe (PMe ) have been corner-

2

3 4

stones in the development of modern cobalt and iron

organometallic chemistry, and an advantage of their use is

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that they release chemically inert methane, which is not for 1, 6.40 pm for 2, and 6.86 and 7.12 ppm for 3 with an

expected to interfere in the reaction pathway or product upfield shift (Δ ≈ 1.04 ppm) compared with the signal of

formation. On the basis of our previous work on imine- the free vinylic derivative.

directed C–H bond activation,^[in this paper, we show

13]

2

that related pyridyl complexes also promote vinylic C(sp )–

H bond activation of 2-vinylpyridine derivatives, which are

related to the isoelectronic imine derivatives through their

interchanged 1,4-azadiene topology (Scheme 1), and extend

our investigation towards π-acceptor ligand substitution

(carbon monoxide) and oxidative addition (iodomethane);

we also explore the limitations of their structure and reac-

tivity relationship (bite angle) when compared with the re-

activity of the isostructural imine complexes.^[

14]

The ¹³C{ H} NMR spectra of 1–3 are consistent with

the spectra of other transition-metal compounds containing

a metalated 2-vinylpyridine ligand. In this context, it should

be mentioned that the deprotonation produces an increase

of electron delocalization in the five-membered ring, as

demonstrated by the downfield shift of the Co–C signal (δ

1

Scheme 1. Interchanged 1,4-azadiene topology of structural iso- ≈ 189.5–192.1 ppm, for 1–3), which provides no evidence of

mers with N exchanged for CH.

the carbene resonance for a significant contribution from a

cobalt–alkenyl bond as found for osmium or rhenium 2-

The cyclometalation reactions of isoelectronic 2-phen-

[

19,21b,26]

vinylpyridine complexes.

Catalytic reactions require

ylimine (A; Scheme 1) derivatives have been extensively

ligand exchange reactions before carbon–carbon bond for-

[

15]

[16]

[17]

studied with Ru,

Pt,

and Ir.

Notably, only a few

[

27]

mation.

The treatment of 1–3 with carbon monoxide

examples of cyclometalated 2-vinylpyridine derivatives (B)

failed to liberate stoichiometric amounts of PMe ; more-

3

have been reported, and there are selected examples of 4d

over, we observed complete demetalation of the pyridyl

backbone and the formation of dinuclear cobalt tetracarb-

onyl complexes (IR) and the free pyridine derivative.^[

Complexes 2 and 3 were isolated as green crystals

suitable for X-ray crystallographic study. ORTEP depictions

of these compounds are shown in Figures 1 and 2, and

selected geometric values are summarized in Table 1. For

five-coordinate structures, an index τ was introduced by

[

18]

[19]

[20]

and 5d transition metals with M = Pd,

Pt,

Os,

Ru^[

21]

2

Ir,

[22]

and Au,

[23]

in most cases achieved through

C(sp )–H activation to assemble complexes of the type

28]

2

[

M(k -C,N-CH=CH–C H N)].

5 4

However, the reactions of first-row transition metals with

-vinylpyridine and -pyrazine derivatives are scarce, al-

2

though cobalt complexes have recently been shown to cata-

lyze the C–C coupling reactions of 2-vinyl nitrogen-contain-

[

29]

Addison et al. to define the extent of deviation from tri-

gonal-bipyramidal to square-pyramidal geometry (τ = 1 for

perfect trigonal bipyramidal; τ = 0 for perfect square-based

[

24]

ing heteroaromatic compounds with styrylboronic acid.

Mechanistically, a cyclometalated alkenylpyridine complex

has been suggested as one of the key intermediates in the

ruthenium-catalyzed arylation of 2-alkenylpyridines with

[

25]

aryl bromides.

Results and Discussion

Synthesis and Characterization of Cyclometalated 2-

Vinylpyridyl Derivatives

The treatment of CoMe(PMe ) with equimolar amounts

3

4

[

14]

of 2-vinylpyridine,

2-(1-phenylvinyl)pyridine, or 2-vinyl-

pyrazine at –70 °C resulted in the formation of the cyclo-

2

metalated complexes (κ -C,N-R R C=CH)Co(PMe ) (1:

1

2

3 3

R = C H N, R = H; 2: R = C H N, R = Ph; 3: R =

1

5

4

2

1

5

4

2

1

C H N , R = H) accompanied by the liberation of meth-

4

3

2

ane [Equation (1)]. Concentrated n-pentane solutions at

27 °C afforded almost black rhombic crystals, which dis-

–

solve in hydrocarbon solvents to produce green solutions.

1

The H NMR spectra of 1–3 in tetrahydrofuran (THF)

show the absence of the cobalt–methyl protons and the

appearance of a new set of signals at δ = 6.32 and 6.66 ppm 50% probability ellipsoids.

Figure 1. Depiction of the solid-state molecular structure of 2 with

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pyramidal). The values for 2 (τ = 0.85) and 3 (τ = 0.81) nation. Additionally, ³¹P NMR spectroscopy showed the

indicate slight deviations from the regular trigonal-bipy- presence of a plethora of unidentified byproducts and the

ramidal geometry, and the metalated carbon atom and sin- absence of the typical triplet/doublet spin-pattern expected

gle PMe ligand occupy apical positions. The metal coordi- for a cyclometalated iron metallacycle in an octahedral co-

3

[

13]

nation sphere is completed by the N donor atom of the ordination sphere.

pyridyl ligand and two PMe ligands in equatorial posi-

3

tions. The Co–P1 and Co–P2 bond lengths fall in the usual

range for trimethylphosphane-stabilized cobalt(I) com-

plexes. The molecular structures of 2 and 3 demonstrate

geometric values similar to those of a manganese complex

with a 2-benzocymantrenylpyridine ligand,^[

30]

and these

complexes are the first structurally characterized cyclomet-

alated 2-vinylpyrazine cobalt complexes.^[

31]

Reactions with Iodomethane

With iodomethane, the interesting question is whether

the attack by the cobalt species would proceed as a regio-

selective addition or promote ring opening through a subse-

[

32]

quent reductive C–C coupling reaction,

related iron–imine complexes.

as observed for

[

13]

Within 2 h, the reaction

mixture turned orange-brown, and a white precipitate of

tetramethylphosphonium iodide indicated that the reaction

proceeded according to Equation (3).

Figure 2. Depiction of the solid-state molecular structure of 3 with

50% probability ellipsoids.

When excess iodomethane was used (Co/MeI ca. 1:5),

Table 1. Selected bond lengths [Å] and angles [°] of the cyclo- large amounts of decomposition products were isolated

I

metalated Co complexes 2 and 3.

[33]

[34]

such as CoI(CH ) (PMe )

and CoI(PMe₃)₃.

Ad-

3

2

3 3

2

3

ditionally, a small amount of a third byproduct demon-

strated by a singlet H NMR resonance at δ = 2.35 ppm,

1

_C_o_–_C₍_s_p2₎

1.8995(4)

1.9919(12)

1.352(2)

1.9058(19)

1.9428(14)

1.348(3)

typical for and Ar–CH derivative, suggests that intramolec-

Co–N₂

3

2

σC(sp )–C(sp )

Co–Peq

ular reductive C–C coupling of the Co–CH moiety and the

3

2.1502(5)

2.1708(5)

2.2010(4)

80.46(6)

176.50(5)

96.24(4)

2.1869(5)

2.1761(6)

2.2159(5)

81.55(8)

178.00(6)

96.46(5)

pyrazyl backbone of 6 occurs to form a methylated pyrazine

derivative. Unfortunately, crystals suitable for X-ray diffrac-

tion could not be obtained to verify this suggestion. The

solution IR and NMR spectroscopic data for all new com-

pounds [e.g., IR: ν˜ ≈ 1162–1157 cm^–¹δ (Co–CH );

Co–Peq

Co–Pax

2

C(sp )–Co–N

2

C(sp )–Co–Pax

N–Co–Pax

as

3

P

ax–Co–Peq

eq–Co–Peq

97.01(2)

112.04(2)

96.38(2)

112.04(2)

13

1

C{ H} NMR: δ = 184.5 ppm (m, Co–C=C); H NMR: δ

3

≈

0.30–0.45 (t, J ≈ 10 Hz, Co–CH )] enabled the stereo-

P,H

3

31

1

chemical assignments for 4–6; in particular, the P{ H}

NMR spectra all manifested singlets, consistent with a trans

disposition of the trimethylphosphane ligands and in agree-

ment with the X-ray structural determination (Figures 3

and 4) of approximately octahedral geometries for 4–6 in

Attempted Cyclometalation of 2-Alkenylpyridines with

Fe(CH ) (PMe )

3

2

3 4

The treatment of stoichiometric amounts of 2-vinylpyr- the solid state. These structures are closely related to five-

idine or 2-(1-phenylvinyl)pyridine with Fe(CH ) (PMe ) membered imine cobaltocycles, in which a strong trans in-

Equation (2)] under analogous conditions as those de- fluence of the methyl group is recognized. The upfield range

3

2

3 4

[

1

scribed for CoCH (PMe ) [Equation (1)] provided low- in the H NMR spectra for the Co–CH resonances of 4–6

3

3 4

3

valent Fe(PMe ) and ethane (C H ) by reductive elimi- is diagnostic that the methyl group is trans to the nitrogen

3

4

2

6

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donor. Crystals of 5 and 6 are stable in air for more than chelating ligand [C7–Co1–N1 81.02(13)°] reflect the spatial

two hours and could thus be mounted on an X-ray requirements of the iodo ligand. The sum of the internal

diffractometer without inert-gas protection. The X-ray angles (539.8°) indicates a slightly distorted five-membered

structure determination data were obtained from low-tem- metallacycle. The strong trans influence of the Co–CH₃

perature measurements under a N stream to provide high- group in 5 causes an elongation of the Co1–N1 bond by

2

quality X-ray parameters (Table 5). The molecular structure 0.045 Å compared with that of the corresponding parental

of 5 (Figure 3) confirms the octahedral configuration cobalt complex 2. Remarkably, the Co–N bond lengths for

derived from the spectroscopic data. The iodo and methyl 2, 3, 5, and 6 are ca. 0.10–0.15 Å shorter when compared

ligands lie in the plane of the chelate ring, and the two with those of a related square-based pyramid configuration,

Co–C bonds are mutually cis [C7–Co1–C8 92.20(17)°]. The which might be attributed to the missing trans nitrogen

[

35]

3

trimethylphosphane ligands approximately eclipse each donor ligand of this complex.

The Co–C(sp ) bond

other, as indicated by their idealized mirror symmetry with length of 5 [2.015(4) Å] is 0.145 Å longer than the average

respect to the Co–I and Co–C bonds. Both PMe ligands distance between cobalt and aryl carbon atoms but still in

3

appear slightly bent [P2–Co1–P1 171.81(5)°] towards the the range of cobalt–carbon distances reported previously.^[

Co–CH₃group. This bending and the bite angle of the The structural values determined for 5 closely resemble

those of the 2-vinylpyrazyl derivative 6 (Figure 4, Table 2).

36]

Table 2. Selected bond lengths [Å] and angles [°] of the methyl–

III

Co complexes 5 and 6.

5

6

2

Co–C(sp )

1.875(3)

2.015(4)

2.037(3)

1.341(5)

2.6943(5)

2.2165(11)

2.2078(12)

81.02(13)

92.20(17)

175.15(10)

94.46(8)

1.874(3)

2.077(3)

2.024(2)

1.332(4)

2.7214(5)

2.2194(9)

2.2229(9)

81.42(13)

91.30(13)

174.98(10)

93.59(7)

172.04(4)

3

Co–C(sp )

Co–N

2

σC(sp )–C(sp )

Co–I

Co–P1

Co–P2

2

C(sp )–Co–N

C(sp )–Co–C(sp )

C(sp )–Co–I

2

3

2

N–Co–I

P1–Co–P2

171.81(5)

Subsequent Double Vinylic Activation of C H N(Ph)–

Figure 3. Depiction of the solid-state molecular structures of 5 with

0% probability ellipsoids.

6

4

5

C=CH

2

The treatment of CoMe(PMe ) with 2 equiv. of 2-(1-

3

4

phenylvinyl)pyridine in n-pentane under ambient condi-

tions for 2 h is accompanied by the release of methane and

three trimethylphosphane ligands to afford the dark brown

complex 7, which is isolated in 83% yield [Equation (4)].

Similarly, 2 is converted to 7 with 1 equiv. 2-(1-phenylvinyl)-

pyridine, as monitored by NMR spectroscopy. Remarkably,

the analogous reaction with 2 equiv. of 2-vinylpyridine

failed to form a similar complex owing to its weaker π-

[

37]

backbonding ability.

We found no evidence of a second isomer containing the

η -bound vinyl substituent of the 2-(1-phenylvinyl)pyridine

ligand in anti fashion, as previously reported for the reac-

2

Figure 4. Depiction of the solid-state molecular structures of 6 with

0% probability ellipsoids.

5

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tion of OsH Cl (PiPr ) with 2-vinylpyridine.^[³⁸^]Dark

2

3 2

brown cubic crystals of 7 were obtained by recrystallization

from n-pentane solution at –27 °C. Solid 7 can be handled

at room temperature for days without signicant decomposi-

tion; however, solutions decompose over weeks at room

temperature, and cobalt metal is deposited. Complex 7 con-

tains two substrate molecules. One of them is metalated, as

2

a consequence of the C(sp )–H bond activation of the vin-

ylic CH substituent, whereas the other one is coordinated

2

to the cobalt atom by the nitrogen atom and the C=C

2

double bond in an η fashion. In agreement with both types

of coordination mode of the pyridine ligands in 7, the

1

3

1

C{ H} NMR spectrum shows two groups of vinylic reso-

2

nances, those of the η -coordinated substituent are typically

upfield-shifted and are observed as a singlet at δ = 38.1 pm

2

and a doublet at δ = 60.5 ppm with J = 11.3 Hz, whereas

P,C

the metalated vinyl carbon atom appears as a multiplet at

δ = 199.5 ppm, in a similar range as that observed for the

parent complex 2 (δ = 191.2 ppm).

Figure 5. Depiction of the solid-state molecular structure of 7 with

50% probability ellipsoids.

To gain further insight into the electronic properties of

7, the gas-phase structures were optimized by using three

dierent DFT functionals, namely, PBE0, B3PW91, and

M06L, in combination with the TZVP basis set. The opti-

mized geometry and solid-state structure of 7 both possess

X-ray Structure Determination of 7

I

a distorted square-planar geometry around the Co center,

Single crystals of 7 suitable for structural analysis by X-

ray crystallography were directly obtained from the synthe-

sis in n-pentane. An ORTEP depiction of the solid-state

molecular structure is shown in Figure 5, and the X-ray

crystallographic collection and refinement parameters are

included in Table 5. The molecule has no symmetry; and

distinct from the more commonly observed trigonal-bi-

pyramidal geometry found for the monocyclometalated

parent complex 2. The structural parameters of the energy-

optimized structure are within 0.04 Å of those of the crystal

structure, except for the carbon–hydrogen bond lengths,

which as usual are systematically underestimated by ca.

2

the atoms of the σ-metallated and η -bound vinyl(phenyl)-

pyridyl ligands lie almost in perpendicular planes, and the

0

.10 Å in the X-ray diraction results. The best results were

obtained with the PBE0/TZVP level of theory (Table 3)

e.g., Co(1)–C(7) in 7: calcd. 1.86507 Å, exp. 1.865(3) Å].

single PMe ligand occupies an equatorial position. The

3

[

bond angles around the distorted trigonal-pyramidal cobalt

center (τ = 0.66) are close to 90°, and the smallest one

The highest occupied molecular orbital (HOMO) of the

2

doubly activated σ- and η -vinylpyridine of 7 (Figure 6; for

[

77.9(1)°] involves the five-membered chelate ring. The

2

HOMO–1 to HOMO–4, see the Supporting Information) is

mainly located at the pyridyl N-donor atom of the cyclo-

metalated σ-vinyl substituent. The HOMO also represents

metalated vinyl carbon atom lies trans to the second η -

bound N coordination site of the vinylpyridine ligand, and

the Co(1)–C(7) bond length of 1.865(3) Å is short com-

pared to the usual values for vinyl carbon bonds (1.98–

[

39]

2.06 Å).

There is no structural hint for agostic interac- Table 3. Geometric parameters for 7 from DFT calculations

[

B3PW91, PBE0, M06L (TZVP)] and from the X-ray crystal struc-

tions in the void opposite the Co(1)–N(1) bond, the Co–P

[a]

distance [2.4134(8) Å] is in the typical range,^[and the

36]

ture.

longer Co(1)–N(2) bond [2.033(2) Å] compared with the Parameter^[^b^]

B3PW91 PBE0

M06L

X-ray

Co(1)–N(1) bond [1.986(2) Å] reflects the strong trans influ-

ence of the Co1–C7 bond, which is shorter than those of Co(1)–N(1)

Co(1)–C(7)

1.86587

2.01240

1.95834

2.04296

2.07074

1.36088

1.44967

2.19395

81.733

1.86507

1.86523

2.03147

1.96600

2.03151

2.07676

1.36205

1.45003

2.17811

81.563

1.865(3)

1.986(2)

1.980(3)

2.024(2)

2.033(2)

1.339(4)

1.457(4)

2.1648(8)

81.50(11)

167.82(11)

103.27(6)

95.17(9)

107.01(9)

2.00699

1.94893

2.02746

2.06111

1.35875

1.44983

2.18297

81.866

Co(1)–C(20)

related cobalt–imine complexes (2.11–2.12 Å). The C(6)–

2

Co(1)–C(19)

Co(1)–N(2)

C(6)–C(7)

C(7) bond length of 1.339(4) Å is typical for an sp –sp

double bond, whereas the elongated C(19)–C(20) bond of

1.457(4) Å reflects the metal π-coordination. The double C(19)–C(20)

Co(1)–P(1)

metalated adduct 7 is related to previously reported osmium

[

21a,38]

C(7)–Co(1)–N(1)

C(7)–Co(1)–N(2)

N(1)–Co(1)–P(1)

complexes

containing both coordination modes for

164.771

103.295

164.898

102.853

95.929

164.043

103.462

95.204

the cyclometalation of 2-vinylpyridine. Remarkably, mono-

nuclear first-row late-transition-metal species with a five-

N(1)–Co(1)–N(2) 95.961

membered cyclometalated 2-vinylpyridine ligand and an C(20)–Co(1)–P(1) 100.601

100.907

103.735

2

additionally η -bound coordination motif have rarely been

[

a] Distances in [Å] and angles in [°]. [b] The atom numbering for

structurally characterized.^[

21a,22,38,40]

the DFT results relate to the X-ray numbering scheme.

Eur. J. Inorg. Chem. 0000, 0–0

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the main π bonding interaction between C19 and C20, lize the cobalt–methyl group within cyclometalation pro-

which is polarized toward the Co center, whereas the cesses for an envisaged vinylic C–H activation in a potential

LUMO is its antibonding counterpart. On the other hand, five- or six-membered metallacycle. The treatment of

the HOMO–1 represents the remaining double bond (CoMe(PMe ) in n-pentane at low temperature (–70 °C)

3

4

character of the σ-coordinated 2-vinylpyridyl moiety. Over- with 8-vinylquinoline produced a dark violet solution and

2

all, the electronic properties of the optimized structure of 7 a brown precipitate, from which the η -bound complex

3

2

obviates the incorporation of a possible Co–H species (κ ,η -C,C,N-C H N–CH=CH )Co(CH )(PMe ) (8) was

9

6

2

3

3 2

within the void opposite the N1–Co1 axis.

isolated as dark violet needles in 74% yield [Equation (5)].

Complex 8 is also produced if the reaction is carried out

in THF or benzene over extended reaction periods. THF

solutions of CoMe(PMe ) and 8-vinylquinoline were moni-

3

4

tored during product formation, and we found no evidence

of a potential six-membered metallacycle or a possible

[

42]

cobalt–carbene complex,

obtained from the Grubbs second-generation catalyst

(H IMes)(PCy )(Cl) Ru=CHPh, H IMes = 1,3-bis-(2,4,6-

which can be conveniently

[

2

3

2

trimethylphenyl)-2-imidazolidinylidene] and vinyl-substi-

tuted quinoline and quinoxaline through a ligand exchange

[

43]

procedure.

Additional attempts to mobilize the remaining methyl

group of 8 and force cyclometalation through C–H acti-

vation failed when a benzene solution of 8 was heated to

55 °C for 4 h; therefore, the product complex is extremely

stable, and only small amounts of unidentified byproducts

were observed. In the IR spectrum of 8, C=CH stretching

2

–1

vibrations are observed at ν˜ = 1568 cm , and deformation

vibrations are observed at ν˜ = 1169 and 1142 cm , as

usually found for η -bond alkenyl groups and cobalt-bound

methyl groups, respectively. The H NMR spectrum of this

–1

2

1

compound in THF at room temperature shows three

characteristic upfield signals and NOE effects were

2

31

observed between the η -bound vinylic group and the

P

nuclei when this signal was irradiated. The signals of the π-

coordinated Co–CH=CH moiety were detected at δ = 1.93,

2

2.02, and 2.64 ppm, and the observation of two separated

signals for the asynchronous PMe ligands and the signal

3

of the retained CoCH group at δ = –1.77 as an apparent

3

broad triplet with J

= 7.2 Hz indicate high phosphane

P,H

exchange mobility within the limited time scale of the spec-

trometer. The singlet observed in the ³¹P{ H} NMR spec-

1

trum at δ = 15.5 ppm decoalesced below 243 K and resolved

2

into two doublets with J = 61.3 Hz; therefore, the cobalt

P,P

environment is asymmetric. The estimated free activation

Figure 6. HOMO (top) and LUMO (bottom) of 7 as calculated by

DFT (PBE0/TZVP).

[

44]

energy of the dynamic process is 11.4 kcal/mol. Similarly

1

13

1

to the H NMR spectrum, the C{ H} NMR spectrum

demonstrates an upfield shift of the characteristic resonance

of the σ-bound Co–CH group (Figure 7), which appears

3

Retaining a Co–CH Group with 8-Vinylquinoline

3

2

as a triplet at δ = –14.5 ppm with J = 12.7 Hz, whereas

P,C

We investigated further structure–reactivity relationships the resonances of the olefinic π-bound carbon atoms appear

2

by using the 8-vinylquinoline ligand, which can be consid- as doublets at δ = 49.7 and 53.8 ppm with J = 16.4 and

P,C

ered to have a flexible bite angle,^[⁴¹^]in an attempt to mobi- 16.7 Hz, respectively, as resolved by DEPT experiments.

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Remarkably, 8 is the first structurally characterized cyclo- Reductive Elimination through CH –CH Loss from cis-

3

2

metalated 8-vinylquinoline complex bearing an η -bound Fe(CH ) (PMe )

vinyl group.

3

2

3 4

[

31]

Previous reports of various aryl C–H bond activation re-

[

12d,14,47]

actions of related aryl imine

or arylaza–allylpyr-

[

48]

idine ligands with Fe(CH ) (PMe ) prompted efforts to

3

2

3 4

affect the related arylation of benzannulated pyridines, as

observed with CoMe(PMe ) [Equation (4)]. The reaction

3

4

of Fe(CH ) (PMe ) with 8-vinylquinoline [Equation (6)]

3

2

3 4

was examined even though it does not form a five-

membered metallacycle through C–H activation with cobalt

adducts. We were interested here in the degree to which the

nitrogen donor would bind to the Fe center and whether

such binding might assist the conversion of this olefin to a

six-membered metallacycle or a carbene-type complex^[

and give additional mechanistic insight into the previously

reported conversions with closely related phenylimines.^[

When solutions of the starting materials were combined at

1

3

1

Figure 7. Experimental 125 MHz C{ H} NMR spectrum of 8 at

[

45]

2

98 K in [D

8

]THF;

the expansions show the resonances of the

metalated σ- and π-bound carbon atoms.

43,49]

13]

The molecular structure of 8 has been confirmed by an

X-ray diffraction study. The crystallographic details as well

as selected bond lengths and angles are given in Table 5.

The X-ray structure shown in Figure 8 clearly reveals that

the complex is a neutral, low-valent cobalt(I) molecule with

–

70 °C [Equation (6)], the reaction mixture turned dark

4

brown within 10 min. Red-brown crystals of (κ ,η -

C,C,C,C-C H N–CH=CH )Fe(PMe ) (9) were isolated; 9

9

6

2

3 3

is extremely air-sensitive in solution, and crystals ignite

within seconds in contact with air.

two PMe ligands, the remaining cobalt–methyl group, and

3

2

an κ ,η -8-vinylpyridine ligand coordinated to the cobalt

center through the N atom and C2 and C3 of the vinyl

substituent. The complex adopts an almost perfect trigonal-

bipyramidal structure (τ = 0.97) with N1–Co1–C1 =

172.35(9)° at the apical positions and with the quinolinyl

backbone and the methyl group in the same plane. The

CH=CH vector is essentially perpendicular to the equato-

rial plane, that is, parallel to the Co–P bonds. The Co–C

In situ ¹H NMR spectroscopy with a cold sample

bonds [1.982(2) and 1.998(2) Å] and the C–C bond

2

[

1.424(4) Å] associated with the η -bound vinyl substituent (–50 °C) of stoichiometric amounts of cis-Fe(CH ) -

3

2

are in the typical range reported for other olefin–cobalt (PMe ) and 8-vinylquinoline in [D ]THF showed first the

3

4

8

[

46]

complexes.

exchange of one PMe ligand, and the pyridyl N donor

3

ligand was preferred over the vinylic group. A stable iron

dimethyl complex through N-pyridyl coordination was re-

cently established in our work with 2-benzoylpyridine.^[In

the NMR spectra, increased line broadening is observed.

The resonances of both separated methyl groups arise as

50]

1

broad singlets in the H NMR spectrum (δ = –1.11 and

0.59 ppm). Afterwards, the intact dimethyl moiety converts

within minutes through the reductive elimination of ethane

instead of Ar–CH elimination, and the released trimeth-

3

ylphosphane-supported Fe⁰source prefers exocyclic η -

bound aryl/vinyl coordination rather than the coordination

of the pyridyl donor linkage. By contrast, we previously ob-

4

2

served a regioselective C–H activation preceded by a Csp –

Csp elimination product (aromatic backbone) with related

3

[

13]

imines

or with a cyclometalated platinum(IV) com-

In addition to the formation of 8, a plethora

of unidentified side products were observed in the P{ H}

NMR spectrum. Previous reports of structurally related

complexes with a pyridyl–imine backbone showed the

retention of the dimethyliron moiety without evidence for

C–C coupling and subsequent degradation upon thermoly-

[

16a,51]

plex.

31

1

[

52]

sis.

The solid-state structure of 9 was established by an

X-ray diffraction study of single crystals obtained from n-

pentane, and the asymmetric unit contains two chemically

Figure 8. Depiction of the solid-state molecular structures of 8 with

0% probability ellipsoids.

5

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2

equivalent but crystallographically independent molecules tion (7)]. Solutions of (κ -C,N-C H N)Fe(CH )(PMe )

3 3

13

6

3

(Figure 9).

(10) decompose rapidly in THF at room temperature, but

cooled solutions in n-pentane are relatively stable. Dark

violet crystals from concentrated n-pentane solutions were

isolated in up to 56% yield. This is remarkable because a

similarly conducted reaction with Co(CH )(PMe ) failed

3

3 4

to form cyclometalated products.

1

H– H NOESY experiments indicated a mer-trans/cis

configuration across the Fe–P bond, as a cross-peak signal

between the Fe–CH group and the methyl protons of the

3

trimethylphosphane ligand was observed. The mer-trans to

mer-cis isomerization of 10 in solution was followed by ³¹

NMR spectroscopy at room temperature. The mer-cis/trans

ratio of ca. 1:10 changed after 5 h. Additionally, the process

for 10 was more complex as, in addition to mer–trans iso-

P

Figure 9. Depiction of the solid-state molecular structure of 9 (only

one of crystallographically independent molecule in the asymmetric

unit).

In the mononuclear complex 9, the Fe(PMe ) moiety is merization, a cyclometalated iron(II) hydride byproduct

3

4

η -coordinated to the exocyclic C=C group (C111 and was observed from cis-FeMe (PMe ) followed by reductive

2

3 2

C110) and to the aromatic carbon atoms (C108 and C107) C–C coupling (Ar–CH ) and the release of 10-methyl-7,8-

3

of 8-vinylquinoline. The vinylic group lies in the same plane benzoquinoline (NMR spectroscopy) accompanied by the

as the aromatic backbone and is bent away from the nitro- release of transient Fe(PMe ) , which activates the C–H

3

4

gen donor group (N1). The bond lengths and angles are as bond of the quinoline backbone.^[¹³^]

expected and, for example, closely resemble those of the

Although the molecular geometry of 10 has not been

1

structure obtained by the photolysis of [(C F ) - clarified owing to poor crystal quality, the H NMR signals

2

5 2

53]

[

PCH CH P(C F ) ]Fe(CO) in the presence of styrene.

of the retained Fe–CH group as a singlet at δ = –0.58 ppm

2

5 2

3

If we define the atoms P11, P12, and P13 and the midpoints and in particular the two sets of triplet/doublet phosphorus

3

1

of the C111–C110 and C102–C108 bonds as the ligand po- resonances for the PMe ligands in the P{ H} NMR spec-

3

2

sitions, the geometry around the iron center is trigonal bi- trum at δ = 17.2 and 27.9 ppm with J = 38.2 Hz and at

P,P

2

pyramidal. Atoms P11, P12, and the C107–C108 midpoint δ = 31.3 and 43.2 ppm with J = 63.5 Hz suggest the

P,P

occupy the equatorial positions, and the PMe group (P13) presence of two isomers with mer-trans (90%) and mer-cis

3

occupies one of the axial positions. In the other axial posi- (10%) configuration, respectively. The structural prefer-

II

tion, the C110–C111 midpoint deviates from the ideal trigo- ences of six-coordinate diorganyl Fe complexes have been

nal-bipyramidal geometry with a maximum angle of 47.5°, thoroughly analyzed previously, since 7,8-benzoquinoline is

which is due to the fixed geometry of the vinylic group co- commercially available. The activation of the aryl C–H

ordinated to the aromatic ring. Thus, the bond lengths and bond to form five-membered metallacycles has been repeat-

4

angles are as expected for η -diene coordination for a low- edly studied in recent years, typically with the fourth- and

4

[57,58]

valent iron(0) coordination. Low-valent η -bound fifth-row late-transition elements Pd, Pt, Ru, and Ir,

It

monoiron aryl complexes are rare, and a distortion from should be noted that a similar reaction of cis-FeMe₂-

4

6

[54]

arene planarity is observed for [Fe(η -C H )(η -C Me )]

(PMe₃)₂with a related diphenyl ketimine (Ph C=CNH)

1

0

8

6

2

and strictly bound aromatic bonds are found in [K(18- ligand resulted in reductive Ar–CH coupling followed by

3

4

[13]

crown-6){Cp*Fe(η -C H )}] (Cp* = pentamethylcyclo- reinsertion to form a stable Fe–H complex.

1

0

4

8

[55]

pentadienyl) or [Fe(η -C H ){P(OMe ) }].

Interest-

1

4

10

2

3 3

6

ingly, nitrogen-site-selective η - or η -bound transition-

metal coordination within structurally characterized N- Arylation through CH

2

Loss Accompanied by η -Vinyl

)(PMe

4

heterocyclic aromatic derivatives is rare.^[

31,56]

Coordination from Co(CH

)

3 4

3

Double C–H bond activation can be envisaged with 2-

2-naphthalene-1-ylvinyl)pyridine and Co(CH )(PMe ) , as

(

3

3 4

Synthesis of Cyclometalated 7,8-Benzoquinoline

[

47b,59]

observed previously with Fe(CH ) (PMe ) .

For the

3

2

3 4

In pursuit of new vinyl-substituted N-heterocyclic treatment of Co(CH )(PMe ) with the vinylpyridyl ligand

3

3 4

benzannulated complexes, we studied the cyclometalation [Equation (8)], aryl C–H activation is observed in the first

of related 7,8-benzoquinoline with Fe(CH ) (PMe ) [Equa- step without consecutive vinylic C–H activation, which can

3

2

3 4

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2

be attributed to the combined effects of the inertness of the = 16.3 Hz and at δ = 68.8 ppm with J = 23.8 Hz. Simi-

P,C

larly to that of 8, the ³¹P{ H} NMR spectrum of 11 at

1

vinylic C–H bond after π-coordination.

–70 °C shows two unresolved resonances as broad singlets

at δ = 2.52 and 6.79 ppm, indicating high ligand mobility.

Additional attempts at the subsequent thermolysis of 11 led

to degradation, and no tractable products of a second

2

vinylic C(sp )–H activation could be obtained; hence, these

species were not pursued or fully characterized except for

routine NMR spectroscopy studies. From n-pentane at

–27 °C, a crystal suitable for the characterization of 11 by

single-crystal X-ray analysis was obtained. The results of

the X-ray studies (ORTEP depiction in Figure 11) showed

From n-pentane solutions, dark red rhombic crystals of that the overall geometry around the Co atom in 11 is

1

1 were obtained. Under argon, decomposition is noticed approximately trigonal bipyramidal (τ = 0.89); the pyridyl

2

above 116–119 °C. The IR spectrum contains absorption and aryl substituents are in the apical positions, and the η -

–

1

bands at ν˜ = 1581 and 1565 cm [ν(C=C)] with a batho- bound alkenyl backbone and two PMe ligands are in the

3

–

1

chromic shift (ca. 70 cm ) for the vinylic group caused by equatorial positions. The bond lengths and angles are in the

metalation. The H NMR spectrum (Figure 10) shows the typical range for previously discussed cobalt–pyridyl com-

1

resonances of the two anisochronically oriented trimeth- plexes (Table 4).

2

ylphosphane ligands at δ = 1.06 and 1.25 ppm with J

=

P,H

6.9 and 5.8 Hz, respectively. The π coordination is clarified

by two upfield-shifted resonances at δ = 3.01 and 4.68 ppm

owing to coordination to the cobalt atom. The aromatic

protons resonate in the typical area between δ = 6.5 and

7.7 ppm (Figure 10).

Figure 11. Depiction of the solid-state molecular structure of 11

with 50% probability ellipsoids.

Table 4. Selected bond lengths [Å] and angles [°] of 11 and 12.

1

11

12

Figure 10. Experimental 500 MHz H NMR spectrum of 11 at

[

45]

2

298 K in [D

8

]THF,

showing the upfield-shifted CoC(sp )–H

2

Co–C(sp )

σ

π

1.9343(16)

2.0057(16)

2.0043(15)

2.0540(13)

1.441(2)

2.2314(5)

2.1827(5)

164.73(6)

84.60(6)/96.78(6)

111.05(2)

–

1.9960(15)

2.0608(14)

2.0508(15)

–

1.431(2)

2.2041(4)

–

resonances.

2

Co–C(sp )

2

Co–C(sp )

Notably, we have not observed an upfield-shifted hydride Co–N

signal in the H NMR spectrum of an in situ experiment C(sp )–C(sp )

with Co(CH )(PMe ) and 2-(2-naphthalene-1-ylvinyl)pyr-

idine, as previously observed for an isoelectronic imine

ligand (N-benzylidene-1-naphthylamine), for which the

complex was furthermore structurally characterized as mer-

1

2

π

Co–Peq

3

3 4

Co–Pax

2

C(sp )

σ

–Co–N

–Co–πC(sp )

ax–Co–Peq

P_e_q–Co–P_e_q

2

C(sp )

σ

π

86.31(6)/83.45(6)

–

113.07(2)

P

3

[59]

(

κ -C,N,C–C H –CH=N–C H )CoH(PMe ) .

Signifi-

6

3

4

1

10

6

3 3

1

cantly, the C{ H} NMR spectrum of 11 correspondingly

contains two upfield-shifted carbon resonances, which are

compatible only with π coordination of the olefin carbon

atoms to the cobalt atom. Both carbon atoms of the olefinic

function in the aromatic backbone produce doublets owing

Monocarbonyl Substitution by the Release of the Pyridyl N

Linkage of 11

to coupling with the phosphorus atoms of the two equato-

rial trimethylphosphane ligands at δ = 47.7 ppm with J_P_,_Ccobalt(I) alkenylpyridine complexes (1–3) and a bicyclo-

A comparison of the reactivity of 11 with those of the

2

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metalated cobalt(III) imine complex^[⁵⁹^]was achieved by

placing solutions of 11 under an atmosphere of carbon

monoxide at 20 °C. Although the related Co(III) imine

complex is inert against oxidative addition,^[

59]

carbon

monoxide smoothly substitutes the pyridine anchoring

group of 11 to form the terminal monocarbonyl complex

12 [Equation (9)]. From n-pentane solution, orange needles

precipitated in 71% yield, and the crystals start to decom-

pose at 155–157 °C.

Figure 12. Depiction of the solid-state molecular structure of 12

with 50% probability ellipsoids.

From the IR spectrum of 12, a terminal carbonyl ligand

–1

is indicated by a strong absorption band at ν˜ = 1954 cm .

1

13

31

1

The H, C, and P{ H}NMR spectra of 12 show the

relationship with the parent complex 11. The signals of the

coordinating alkenyl group are again observed in the up-

atom. The π coordination is well documented by the high-

field shift of the signals of both olefinic carbon atoms

(NMR spectroscopy). The carbonyl group and the met-

1

field area of the H NMR spectrum as doublets of triplets

alated carbon atom (C23) are orientated in the axial

direction [C23–Co1–C7 171.26(7)°]. The bond length be-

tween the metalated carbon atom and the cobalt atom

at δ = 3.66 and 5.01 ppm as well as in the corresponding

1

3

1

C{ H} NMR spectrum as doublets at δ = 60.5 and

6

7.9 ppm, which indicates the π-coordination to the metal

[Co1–C23 1.9960(15) Å] is similar to those for the olefinic

center. The better electron-donating ability of the pyridyl

group causes the terminal carbonyl carbon resonance in the

carbon atoms (C13 and C14). The most-striking structural

feature is the release of N coordination, and the pyridyl ring

is directed away from the metal center. The olefin coordina-

tion in 12 places enough electron density at the metal center

to favor carbonyl binding over the binding of the pyridine

group. Complex 12 is also a rare example of a complex

in which a cobalt atom with oxidation state +1 contains

1

3

1

C{ H} NMR spectrum to move to lower field (δ =

2

18.3 ppm) compared with those of related imine–cobalt

complexes. Complex 12 appears stable in the solid state at

27 °C for weeks but readily decomposes in solution at

–

room temperature, as demonstrated by line broadening and

the appearance of additional peaks in the NMR spectra.

Owing to the high mobility of both asymmetric trimeth-

ylphosphane ligands, only a broad multiplet of overlapping

signals at δ = 12.7 ppm is observed in the P{ H} NMR

spectrum. The overall NMR spectroscopic data confirm

this configuration of 12 in solution, and isomers with ex-

changed carbonyl ligand positions or insertion products are

not detected. The retention of alkenyl-bound π-coordina-

three different types of metal–carbon bonds (Co–C ,

Ar

[31]

Co–CH=CH, Co–CϵO).

3

1

Monocarbonyl Substitution versus Release of Pyridyl N

Linkage

An experimental distinction of the reactivities of the

3

tion for cobaltocycle 12 was confirmed by elucidation of closely related bicyclometalated iron–imine complex (κ -

the molecular structure of crystals grown from concentrated C,N,C-C H –CH=N–C H )Fe(PMe )

n-pentane solution at –27 °C (Figure 12).

[

47b]

and pyridyl-

6

4

10

6

3 3

3

cobalt complex 11 was achieved by placing solutions of (κ -

[

47b]

The cobalt atom is found in a trigonal-bipyramidal coor- C,C,N-C H N–C=CH–C H )Fe(PMe )

under 1 bar

5

4

10

6

3 3

dination environment (τ = 0.96; Figure 12), as typically of carbon monoxide at 20 °C [Equation (10)]. The retention

found for the majority of pentacoordinate organocobalt(I) of the configuration and the regioselective monosubstitu-

[

60]

complexes.

Two PMe₃ligands are held in equatorial tion of the trimethylphosphane ligand trans to the vinylic

positions with typical Co–P distances [Co1–P1 2.2040(4) carbon atom was observed. A similar reaction pathway is

and Co1–P2 2.2180(4) Å]. The third equatorial position is recognized with a series of related iron–imine complexes.^[

occupied by the olefin carbon atoms with similar bond Conversely, with respect to the related reaction pathway of

13]

lengths

[Co1–C13

2.0608(14) Å

and

Co1–C14 11 [Equation (9)], we have no evidence for the release of the

2

.0508(15) Å]. The bond length between the olefinic carbon N-donor linkage of the pyridyl backbone, the insertion of

[

61]

atoms [C14–C13 = 1.431(2) Å] is expanded owing to the the products into the Fe–C/Fe–N bond, or multiple sub-

coordination to the cobalt center and is close to the average stitutions of PMe ligands in the presence of excess carbon

3

value (1.40 Å) for olefin ligands coordinated to a cobalt monoxide.

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ylquinoline, which lacks a suitable bite angle and favors re-

ductive elimination with the loss of ethane from Fe(CH ) -

3

2

(

PMe ) to form 9 with binding solely through the olefinic

3 4

and aromatic carbon π bonds instead of the combination

2

of η -olefin and N-pyridyl coordination observed for the

cobalt complex 8. Investigations of these vinylpyridyl cobalt

and iron complexes are of continuing interest in our studies,

and further experiments to expand their scope are in pro-

gress.

The carbonyl complex 13 forms olive green crystals,

which can be handled in air for several hours and are ther-

mally stable under argon to 157 °C. It is less soluble in n-

pentane and diethyl ether and shows moderate solubility in

THF. The IR spectrum of 13 display characteristic strong

Experimental Section

–

1

bands at ν˜ ≈ 1876 cm for a terminal carbonyl ligand and

General Procedures: Unless otherwise stated, all manipulations

were performed under an inert atmosphere of nitrogen by using

standard Schlenk techniques or an MBraun glovebox. Anhydrous

–

1

ν˜ ≈ 1577 and 1542 cm for metalated aromatic C=C groups

–1

that experience a slightly hypsochromic shift of ca. 11 cm

3

relative to the bands of the parent complex (κ -C,C,N- n-pentane, toluene, diethyl ether, and THF were purchased from

[47b]

31

1

C H N–C=CH–C H )Fe(PMe ) .

The P{ H} NMR Acros, sparged with nitrogen, and passed through activated

spectrum shows a singlet at δ = 21.1 ppm, which is alumina. [D ]Benzene and [D ]THF were dried under reflux with

Na/K alloy in sealed vessels under a partial pressure, trap-to-trap

distilled, and freeze–pump–thaw degassed three times. [D ]Toluene

was purified in an analogous manner at reflux over Na. The H,

5

4

10

6

3 3

6

8

compatible with two isochronic trimethylphosphane ligands

at the trans positions of an octahedral coordination sphere

and a carbonyl ligand in a cis position to produce a mer-

trans arrangement of the six ligands. The better electron-

donating ability of pyridyl group causes the resonance of

8

1

3

1

13

1

P{ H}, and C{ H} spectra were recorded with Bruker DRX

and AMX spectrometers operating at 500 and 300 MHz for the

proton nuclei. All chemical shifts are reported in parts per million,

1

3

1

the terminal carbonyl carbon atom in the C{ H} NMR

1

and all coupling constants are reported in Hertz. The H NMR

spectrum to move to lower field (δ = 234.3 ppm) compared

6 5

spectra were referenced to residual solvent protons (C D H, δ =

3

with that of the isoelectronic iron imine complex (κ -C,C,N- 7.16 ppm; C D H, δ = 2.09 ppm; C D HO, δ = 1.73 ppm) relative

7

4

7

3

1

C H –CH=N–C H )Fe(PMe ) with δ = 218.7 ppm (IR: ν˜ to tetramethylsilane at δ = 0.00 ppm. The P{ H} NMR spectra

6

5

10

1 [47b,59]

6

3 3

–

=

1883 cm ).

To date, the bicyclometalated iron pyr- were referenced to external 85% H

3

PO

C{ H} NMR spectra were referenced to solvent resonances

, δ = 128.0 ppm; C , δ = 20.4 ppm; C O, δ =

4

at δ = 0.00 ppm. The

1

3

1

idyl complex 13 is the only example in which double

(

C

6

D

6

7

D

8

4 8

D

C–H activation produces an structure isoelectronic to those

_o_b_t_a_i_n_e_d_w_i_t_h_i_r_o_n_–_i_m_i_n_e_c_o_m_p_l_e_x_e_s_.[47b]

25.37 ppm). The IR spectra were obtained from Nujol mulls be-

tween KBr plates by using a Bruker FRA 106 spectrophotometer

–

1

and were recorded in the wavenumber range 4000–400 cm .

Elemental analyses of air-sensitive substances were performed by

H. Kolbe Microanalytical Laboratory, Mülheim an der Ruhr (Ger-

many). The C, H, N analyses of air-stable substances were per-

formed in the microanalysis laboratory of the Clemens-Schöpf-

Institut for Organic Chemistry and Biochemistry at TU-Darmstadt

by using a Perkin–Elmer CHN 240 A analyzer. The melting and

decomposition points were measured with a Büchi 510 melting

point apparatus. Air-sensitive substances were sealed in capillaries

Conclusions

A series of vinyl/aryl organocobalt and iron complexes

with pyridyl and pyrazyl ligand backbones were synthesized

and characterized. The resultant cobalt and iron complexes

are low-spin d and d species. At variance with previous

studies of imine ligands, the reverse topology in terms of

6

8

interchanged 1,4-azadiene ligands showed significant differ-

[28a]

[62]

under 1 bar of argon. CoCH

3

(PMe

3

)

4

,

Fe(CH

3

)

2

(PMe

3

)

4

,

tri-

ences in reactivity.^[

13]

The monocyclometalated cobalt(I) methylphosphane, tetramethylphosphonium iodide, and 2-(2-

[63]

[64]

complexes 1–3 readily demetalate from the pyridyl back- naphthalene-1-ylvinyl)pyridine^[

]Benzene and [D

65]

were synthesized by literature

bone in the presence of carbon monoxide but oxidatively methods. [D

6

8

]THF were purchased from Sigma–

III

Aldrich. 2-Vinylpyridine, 2-vinylpyrazine, quinoline-8-carbal-

dehyde, 7,8-benzoquinoline, 2-benzoylpyridine, and n-butyllith-

ium(1.6 m) were purchased from Acros and used as received.

add iodomethane to form stable CH Co I (4–6) metalla-

cycles. Analogous reactions with Fe(CH ) (PMe ) failed to

form the related cyclometalated iron 2-alkenylpyridyl com-

3

2

3 4

plexes. By contrast, bicyclometalated cobalt complexes with 8-Vinylquinoline: At –70 °C, a hexane solution of nBuLi (33.7 mL,

2

an η -alkenyl coordination motif (7, 11, and 12) were ob- 1.6 n, 53.9 mmol) was slowly added to tetramethylphosphonium

iodide (21.8 g, 53.9 mmol) in THF (250 mL). After stirring for 2 h

at 20 °C, the solution was cooled to –20 °C, and quinoline-8-carbal-

tained and simply release their N-donor linkage under

1

atm of carbon monoxide. These differences of the cyclo-

dehyde (8.47 g, 53.9 mmol) in THF (50 mL) was added slowly. Af-

ter warming to ambient temperature, the reaction mixture was

heated to reflux for 5 h and quenched with water (250 mL). The

THF was removed in vacuo, and the residue was extracted with

pentane (3ϫ 100 mL). The organic phases were combined, dried

metalation reaction sequence between Co(CH )(PMe )

3

3 4

and Fe(CH ) (PMe ) depend upon the nature of the L M

3

2

3 4

n

fragment (M = Co, Fe) and suggest that the mechanistic

divergence begins with the initial binding of the pyridine

nitrogen atom to allow a close approach of the vinylic

4

with MgSO , and filtered. The solvent was removed in vacuo, and

hydrogen atom to the unsaturated cobalt complex. A re- distillation under reduced pressure afforded 8-vinylquinoline as a

1

versed competing reaction sequence is observed with 8-vin- colorless oil (isolated yield 9.93 g, 84%); b.p. 121 °C/17 mbar. H

Eur. J. Inorg. Chem. 0000, 0–0

11

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/KAP1

Date: 29-04-15 11:47:37

Pages: 18

www.eurjic.org

FULL PAPER

]THF, 300 K): δ = 5.48 (dd, JH,H = 1.3, ³JH,H

2

[2-(2-Pyrazyl-κN)ethenyl-κC]tris(trimethylphosphane)cobalt(I) (3):

2-Vinylpyrazine (207 mg, 1.95 mmol) in THF (50 mL) was com-

NMR (300 MHz, [D

11.1 Hz, 1 H, C=CH), 6.08 (dd, JH,H = 1.3, JH,H = 17.9 Hz, 1

8

2

3

=

3

4

H, C=CH), 7.48 (ddd, JH,H = 8.3, JH,H = 5.3, JH,H = 1.2 Hz, 1

bined at –70 °C with CoMe(PMe

(50 mL) with the evolution of gas. After 3 h at 20 °C, all volatiles

7.3 Hz, 1 H, Ar-H), 8.14 (d, JH,H = 11.1 Hz, 1 H, Ar-H), 8.24 were removed from the mixture in vacuo, and the solid residue was

3 4

) (740 mg, 1.95 mmol) in THF

3

2

H, CH=CH ), 7.83 (d, JH,H = 8.1 Hz, 1 H, Ar-H), 8.02 (d, JH,H

3

=

3

4

(

dd, JH,H = 8.3, JH,H = 1.5 Hz, 1 H, Ar-H), 8.95 (dd, JH,H = 1.4

extracted with diethyl ether (80 mL). From the solution, dark green

rhombic crystals (350 mg) suitable for X-ray diffraction were ob-

tained. Upon cooling of the solution to –27 °C, a second fraction

of 3 was collected and combined with the first, yield 390 mg (51%);

3

13

1

J

H,H = 2.3 Hz, 1 H, N=CH) ppm. C{ H} NMR (125 MHz, [D

THF, 300 K): δ = 115.6 (s, CH ), 122.2 (s, CH), 125.8 (s, CH),

27.2 (s, CH), 128.6 (s, CH), 129.3 (s, C), 133.9 (s, CH), 136.7 (s,

C), 136.9 (s, CH), 146.4 (s, C), 150.5 (s, NCH) ppm. C11

155.20): calcd. C 85.13, H 5.85, N 9.03; found C 85.01, H 5.72, N

8

]-

2

1

–

1

H

9

N

m.p. 89–91 °C (dec.). IR (Nujol, KBr): ν˜ = 1575 [m, (C=C)] cm .

1

(

H NMR (500 MHz, [D

8

]THF, 300 K): δ = 1.19 (br s, 27 H, PCH

3

),

3

8.90.

6.86 (d, JH,H = 7.3 Hz, 1 H, C=CH), 7.12 (br s, 1 H, C=CH), 7.19

4

(

d, JP,H = 5.5 Hz, 1 H, Ar-H), 8.84 (d, JP,H = 5.0 Hz, 1 H, NCH),

2

-(1-Phenylvinyl)pyridine: The same procedure as that for 8-vinyl-

quinoline afforded 2-(1-phenylvinyl)pyridine (7.0 g, 38 mmol) as a

13

1

9

3

.15 (br s, 1 H, Ar-H) ppm. C{ H} NMR (125 MHz, [D

8

]THF,

1

00 K): δ = 19.2 (d, JP,C = 15.3 Hz, PCH

3

), 121.7 (s, CH), 145.7

1

colorless oil (isolated yield 5.81 g, 84%); b.p. 151 °C/13 mbar. H

(

s, CH), 157.5 (s, CH), 161.4 (s, NC), 192.1 (m, CoC=CH) ppm.

2

NMR (300 MHz, [D

8

2

]THF, 300 K): δ = 5.59 (d, JH,H = 1.6 Hz, 1

31

1

P{ H} NMR (202 MHz, [D

PCH ) ppm. C15 32CoN (392.3): calcd. C 45.93, H 8.22, N

.14, P 23.69; found C 46.20, H 7.80, N 7.22, P 24.02.

8

]THF, 203 K): δ = 4.9 (br s, 3 P,

H, C=CH), 6.12 (d, JH,H = 1.6 Hz, 1 H, C=CH), 7.20–7.37 (m, 7

H, Ar-H), 7.68 (dt, JH,H = 11.4, JH,H = 1.7 Hz, 1 H, Ar-H), 8.61

3

H

2 3

P

3

4

7

3

(

d, JH,H = 8.1 Hz, 1 H, Ar-H) ppm. C13

H11N (181.23): calcd. C

mer-trans-[2-(2-Pyridinyl-κN)ethenyl-κC](iodo)(methyl)bis(trimeth-

ylphosphane)cobalt(III) (4): A sample of 1 (620 mg, 1.58 mmol) in

n-pentane (80 mL) at –70 °C was combined with an excess of iodo-

methane (562 mg, 3.96 mmol). After the mixture was stirred for 2 h

8

6.15, H 6.12, N 7.73; found C 85.99, H 6.03, N 7.61.

[

2-(2-Pyridinyl-κN)ethenyl-κC]tris(trimethylphosphane)cobalt(I) (1):

A solution of 2-vinylpyridine (520 mg, 4.94 mmol) in THF (50 mL)

was added to CoMe(PMe (1.87 g, 4.94 mmol) in THF at –78 °C

50 mL). A rapid color change from dark red to green was observed

3 4

)

4

at 20 °C, a white solid was removed by filtration (PMe I). The

(

orange-brown solution was kept at 4 °C and deposited orange-

yellow crystals (370 mg) with a cubic shape. The volume of the

solution was reduced, and 4 (144 mg) crystallized at –27 °C, yield

as the mixture warmed. After 5 h, the solvent was removed in

vacuo, and the oily residue was extracted with n-pentane (2ϫ

50 mL). Crystallization at 4 °C afforded dark green, rhombic crys-

5

14 mg (71%); m.p. 101–103 °C (dec.). IR (Nujol, KBr): ν˜ = 1576

tals. Isolated yield 910 mg (47%); m.p. 75–77 °C (dec.). IR (Nujol,

–1

1

[w, (C=C)], 1158 [m, (Co–CH

3

)] cm . H NMR (500 MHz, [D

8

]-

–1 1

KBr): ν˜ = 1581 (m, C=C) cm . H NMR (500 MHz, [D

8

]THF,

), 6.32 (d, JH,H = 6.6 Hz, 1 H,

C=CH), 6.66 (d, JH,H = 7.1 Hz, 1 H, C=CH), 7.02 (br s, 1 H, Ar-

3

THF, 300 K): δ = 0.48 (t, JP,H = 9.9 Hz, 3 H, Co–CH

3

), 1.03 (tЈ,

), 6.73 (dd, JH,H = 6.4, JH,H

0.5 Hz, 1 H, Ar-H), 6.78 (dt, JH,H = 6.5, JP,H = 5.1 Hz, 1 H,

3

00 K): δ = 1.23 (br s, 27 H, PCH

3

2

4

3

4

|

J

P,H + JP,H| = 7.7 Hz, 18 H, PCH

3

=

4

H), 7.19 (d, JP,H = 5.4 Hz, 1 H, Ar-H), 8.76 (d, JP,H = 5.1 Hz, 1

H, NCH), 8.87 (dd, JH,H = 7.8, JP,H = 11.4 Hz, 1 H, Ar-H) ppm.

3

Ar-H), 8.14 (br s, 1 H, Ar-H), 8.54 (br s, 1 H, Ar-H), 8.61 (d, JH,H

3

4

=

6.9, JH,H = 0.5 Hz, 1 H, Ar-H), 9.74 (br s, 1 H, Ar-H) ppm.

1

3

1

C{ H} NMR (125 MHz, [D

6.3 Hz, PCH ), 111.5 (s, CH), 119.1 (s, CH), 120.5 (s, CH), 121.7

s, CH), 147.5 (s, CH), 161.4 (s, C), 189.5 (m, Co–CH) ppm.

8

]THF, 300 K): δ = 19.5 (d, JP,C

=

13

1

C{ H} NMR (125 MHz, [D

8

]THF, 300 K): δ = –7.2 (m, Co–

1

3

1

3

CH

3

), 12.2 (tЈ, | JP,C + JP,C| = 14.2 Hz, PCH ), 119.5 (s, CH), 120.9

3

(

s, CH), 126.2 (s, CH), 148.0 (s, CH), 161.5 (s, C), 184.5 (m, Co–

3

1

P{ H} NMR (202 MHz, [D

PCH ) ppm. C16 33CoNP (391.30): calcd. C 49.11, H 8.50, N

.58, P 23.75; found C 48.95, H 8.97, N 3.55, P 23.58.

8

]THF, 203 K): δ = 5.8 (br s, 3 P,

31

1

CH) ppm. P{ H} NMR (202 MHz, [D

br s, 2 P, PCH ) ppm. C14 27CoINP (457.2): calcd. C 36.78, H

.95, N 3.06, P 13.55; found C 35.98, H 6.40, N 3.03, P 13.83.

8

]THF, 203 K): δ = 11.6

3

H

3

(

5

H

3

2

3

[

2-Phenyl-2-(2-pyridinyl-κN)ethenyl-κC]tris(trimethylphosphane)-

cobalt(I) (2): 2-(1-Phenylvinyl)pyridine (380 mg, 2.10 mmol) in di-

ethyl ether (50 mL) at –70 °C was combined with CoMe(PMe

mer-trans-[2-Phenyl-2-(2-pyridinyl-κN)ethenyl-κC](iodo)(methyl)bis-

(trimethylphosphane)cobalt(III) (5): To 2 (890 mg, 1.90 mmol) in n-

pentane (80 mL) at –70 °C, iodomethane (594 mg, 4.18 mmol) was

3 4

)

(

792 mg, 2.10 mmol) in diethyl ether (50 mL). As the mixture added slowly. The dark green mixture was stirred at 20 °C for 2 h

warmed, gas evolution (CH

green and was stirred at 20 °C for 16 h. The volatiles were removed

in vacuo, and the waxy residue was extracted with pentane (3ϫ

4

) was detected; the mixture turned

under 1 bar of argon. A white solid was removed by filtration

through a sintered glass disc (G4), and the resulting orange-brown

solution was kept at 4 °C. Orange plate crystals (680 mg) suitable

for X-ray diffraction were isolated by decantation, washed with a

80 mL). At –27 °C, the solution afforded dark green rhombic crys-

tals of 2, which were suitable for X-ray diffraction, yield 734 mg small amount of cold n-pentane, and dried in vacuo, yield 680 mg

(

75 %); m.p. 101–103 °C (dec.). IR (Nujol, KBr): ν˜ = 1578 [m,

(67 %); m.p. 115–117 °C (dec.). IR (Nujol, KBr): ν˜ = 1580 [w,

–1

1

–1 1

C=C)] cm . H NMR (500 MHz, [D

8

3

]THF, 300 K): δ = 1.24 (d, (C=C)], 1157 [m, (Co–CH

3

)] cm . H NMR (500 MHz, [D

8

]THF,

2

4

3

2

J

P,H = 5.8 Hz, 27 H, PCH

3

), 6.40 (dt, JH,H = 6.4, JH,H = 1.7 Hz,

300 K): δ = 0.30 (t, JP,H = 10.0 Hz, 3 H, Co–CH ), 0.72 (tЈ, | JP,H

3

4

3

4

1

=

H, C=C–H), 7.08 (ddd, JH,H = 7.2, JP,H = 5.9, JH,H = 1.3 Hz,

+

J

P,H| = 7.9 Hz, 18 H, PCH

1.2 Hz, 1 H, Ar-H), 6.32 (dt, JH,H = 8.4, JH,H = 1.1 Hz, 1 H, Ar-

3

), 6.07 (dt,

J

H,H = 7.1,

H,H

J =

3

4

3

4

H, Ar-H), 7.17–7.23 (m, 3 H, Ar-H), 7.30 (dd, JH,H = 8.3, JP,H

4

3

4

3.3, JH,H = 1.5 Hz, 1 H, Ar-H), 8.85 (d, JP,H = 5.3 Hz, 1 H,

H), 6.63–6.67 (m, 3 H, Ar-H), 6.85 (ddd, JH,H = 7.1, JP,H = 4.5,

3

13

1

4

J

H,H = 2.1 Hz, 1 H, Ar-H), 7.05 (dd, JH,H = 6.8, ⁴JH,H = 2.1 Hz,

3

Ar-H), 8.87 (q, JP,H = 12.1 Hz, 1 H, Co–CH) ppm. C{ H} NMR

1

3

4

(

125 MHz, [D

12.4 (s, CH), 118.8 (s, CH), 121.1 (s, CH), 122.7 (s, CH), 126.5 (s,

CH), 127.2 (s, CH), 135.1 (s, CH), 143.2 (s, CH), 148.7 (s, CH), (125 MHz, [D

8

]THF, 300 K): δ = 20.2 (d, JP,C = 16.9 Hz, PCH

3

),

1 H, Ar-H), 7.24 (dd, JH,H = 7.1, JH,H = 1.5 Hz, 1 H, Ar-H), 8.53

(t, JH,H = 6.8, JP,H = 4.6 Hz, 1 H, Ar-H) ppm. C{ H} NMR

3

4

13

1

8

]THF, 300 K): δ = –7.4 (m, Co–CH

58.3 (s, CH), 191.2 (m, Co–C) ppm. ³¹P{ H} NMR (202 MHz, + JP,C| = 12.9 Hz, PCH

), 110.1 (s, CH), 113.5 (s, CH), 118.8 (s,

]THF, 203 K): δ = 5.6 (br s, 3 P, PCH ) ppm. C22 37CoNP CH), 120.1 (s, CH), 123.6 (s, CH), 125.8 (s, CH), 128.6 (s, CH),

467.4): calcd. C 56.53, H 7.98, N 3.00, P 19.88; found C 56.75, H

.40, N 2.97, P 19.91.

3

), 8.52 (tЈ, | JP,C

1

3

1

3

[D

8

3

H

3

1

(

7

137.9 (s, CH), 149.3 (s, C), 183.5 (m, Co–C) ppm. P{ H} NMR

(202 MHz, [D ]THF, 203 K): δ = 8.9 (br s, 2 P, PCH ) ppm.

8

3

Eur. J. Inorg. Chem. 0000, 0–0

12

Job/Unit: I50225

/KAP1

Date: 29-04-15 11:47:37

Pages: 18

www.eurjic.org

FULL PAPER

C

20

H

31CoINP

2

(533.3): calcd. C 45.05, H 5.86, N 2.63, P 11.62;

diffraction. Isolated yield: 940 mg (74%); m.p. 120–124 °C (dec.)

found C 45.11, H 6.38, N 2.67, P 11.86.

IR (Nujol, KBr): ν˜ = 1586 (m), 1568 [w, (C=C)], 1169 (w), 1142

–

1 1

[

–

3 8

w, (Co–CH )] cm . H NMR (500 MHz, [D ]THF, 300 K): δ =

mer-trans-[2-(2-Pyrazyl-κN)ethenyl-κC](iodo)(methyl)bis(trimethyl-

phosphane)cobalt(III) (6): A sample of 3 (560 mg, 1.42 mmol) in

THF (50 mL) at –70 °C was combined with iodomethane (445 mg,

3

2

1.77 (apparent t, JP,H = 7.2 Hz, 3 H, Co–CH

₎_,₁_.₄₀₍_d_,2_JP,H = 4.2 Hz, 9 H, PCH

3

), 0.86 (d, JP,H

), 1.93 (d,

P,H = 7.9 Hz, 1 H, C=CH), 2.02 (dd, JH,H = 7.4, JP,H = 5.3 Hz,

=

4

.8 Hz, 9 H, PCH

3

2

3

J

3

.14 mmol). After 16 h at 20 °C, an off-white solid, tetrameth-

3

4

1

=

(

1

–

1

H, C=CH), 2.64 (t, JH,H = 8.1 Hz, 1 H, C=CH), 6.83 (dd, JP,H

ylphosphonium iodide (IR spectroscopy), was removed by fil-

tration, and the filtrate was evaporated to dryness. Extraction with

diethyl ether (3ϫ 60 mL) and cooling to –27 °C afforded orange-

brown crystals of 6, which were suitable for X-ray diffraction, yield

3

4.9, JH,H = 8.1 Hz, 1 H, Ar-H), 7.04–7.08 (m, 3 H, Ar-H), 7.31

4

3

4

dd, JP,H = 4.5, JH,H = 8.3 Hz, 1 H, Ar-H), 8.39 (d, JP,H = 4.9 Hz,

H, NCH) ppm. C{ H} NMR (125 MHz, [D ]THF, 300 K): δ =

8

13

1

2

1

14.5 (apparent t,

0.7 Hz, PCH ), 16.8 (d, JP,C = 11.7 Hz, PCH

6.7 Hz, CH=CH

J

P,C = 12.7 Hz, CoCH

3

), 15.2 (d,

J

P, C

=

3

98 mg (61%); m.p. 103–106 °C (dec.). IR (Nujol, KBr): ν˜ = 1579

1

2

3

), 49.7 (d, JP,C

), 53.8 (d, JP,C = 16.4 Hz, CH=CH

–1 1

[

m, (C=C)], 1162 [w, (Co–CH

3

)] cm . H NMR (500 MHz, [D

THF, 300 K): δ = 0.45 (t, JP,H = 8.5 Hz, 3 H, Co–CH ), 0.98 (tЈ,

), 6.75 (t, JH,H = 6.4 Hz, 1 H,

8

]-

2

), 117.8 (s,

3

CH), 119.0 (s, CH), 120.1 (s, CH), 125.8 (s, CH), 127.9 (s, C), 130.8

2

4

3

|

J

P,H + JP,H| = 7.6 Hz, 18 H, PCH

3

4

(

s, CH), 151.5 (dd, JP,C = 4.4, JP,C = 4.2 Hz, NCH), 156.3 (s, C)

3

Ar-H), 6.78 (dt, JH,H = 6.5, JP,H = 5.1 Hz, 1 H, Ar-H), 8.21 (br

31

1

2

ppm. P{ H} NMR (202 MHz, [D

8

]THF, 203 K): δ = 13.6 (d, JP,P

), 16.8 (d, JP,P = 61.3 Hz, 1 P, PCH ) ppm.

2

(381.2): calcd. C 56.70, H 7.99, N 3.67, P 16.25;

s, 1 H, Ar-H), 8.52 (br s, 1 H, Ar-H), 8.75 (br s, 1 H, Ar-H), 9.80 (br

2

=

C

61.3 Hz, 1 P, PCH

30CoNP

3

s, 1 H, Ar-H) ppm. ¹³C{ H} NMR (125 MHz, [D

1

]THF, 300 K): δ

P,C| = 14.5 Hz, PCH ),

25.0 (s, CH), 148.0 (s, CH), 144.2 (s, CH), 157.1 (s, CH), 162.5 (s,

8

18

H

1

3

=

1

–6.5 (m, Co–CH

3

), 12.2 (tЈ, | JP,C

+

J

3

found C 56.85, H 7.68, N 3.68, P 16.29.

31

1

2

C), 183.9 (m, Co–CH) ppm. P{ H} NMR (202 MHz, [D

03 K): δ = 10.5 (br s, 2 P, PCH ) ppm. C13 26CoIN (458.2):

calcd. C 34.08, H 5.72, N 6.11, P 13.52; found C 33.76, H 6.03, N

.88, P 13.43.

8

]THF, [(8-Quinolinyl-η -κC,C)ethenyl-η -κC,C]tris(trimethylphosphane)-

2

3

H

2

P

2

iron(0) (9): FeMe (PMe (1.08 g, 2.77 mmol) in n-pentane

2

3 4

)

(30 mL) was combined with 8-vinylquinoline (430 mg, 2.77 mmol)

in n-pentane (50 mL) at –70 °C. Gas evolution was detected as the

mixture warmed, and the mixture turned from orange-brown to

dark brown when it was kept at 20 °C for 10 min. The volatiles

were then removed in vacuo, and the waxy residue was extracted

with n-pentane (2ϫ 50 mL). The solution was cooled to 4 °C to

afford dark red-brown crystals of 9, which were suitable for X-ray

5

2

[

2-(1-Phenyl-η -ethenyl)pyridine][2-phenyl-2-(2-pyridyl-κN)ethenyl-

κC](trimethylphosphane)cobalt(I) (7): A solution of CoMe(PMe

3 4

)

(742 mg, 1.96 mmol) in THF (70 mL) was combined at –70 °C with

2

-(1-phenylvinyl)pyridine (711 mg, 3.92 mmol) in THF (50 mL),

and a gas evolved. The reaction mixture turned from orange-red

to green and finally to brown. After 16 h at 20 °C, all volatiles

were removed from the mixture in vacuo, and the solid residue

was extracted with n-pentane (2ϫ 80 mL). From the solution, dark

brown cubic crystals (357 mg) suitable for X-ray diffraction were

obtained. Upon cooling to –27 °C, a second fraction of 7 was col-

lected and combined with the first, yield 808 mg (83%); m.p. 142–

diffraction, yield 474 mg (39%); m.p. 115–119 °C (dec.). IR (Nujol,

–1

KBr): ν˜ = 1572 (m), 1533 [m, (ν C=C)], 933 [s, ρ

Magnetic moment: μeff = 1.98 μ 30FeNP

4.68, H 8.26, N 3.19; found C 54.38, H 7.62, N 3.25.

1 3

(PCH )] cm .

B

. C20

H

3

(439.3): calcd. C

5

mer-trans-Methyl[(benzo[h]quinoline-10-yl)-κC,κN]tris(trimethyl-

phosphane)iron(II) (10): 7,8-Benzoquinoline (377 mg, 1.85 mmol) in

–

1 1

1

44 °C (dec.). IR (Nujol, KBr): ν˜ = 1579 [m, (C=C)] cm . H

THF (30 mL) was combined with FeMe

2 3 4

(PMe ) (729 mg,

2

NMR (500 MHz, [D

H, PCH ), 2.60 (s, 1 H, C=CH), 2.64 (d,

C=CH), 6.57 (dd, JH,H = 8.1, JH,H = 0.5 Hz, 1 H, C=CH), 6.64– mixture was kept at 20 °C for 5 h. The volatiles were removed in

8

]THF, 300 K): δ = 1.21 (d, JP,H = 7.7 Hz, 9 1.85 mmol) in THF (80 mL) at –70 °C. As the mixture warmed, it

3

J

P,H = 14.1 Hz, 1 H,

became violet-brown, and the evolution of gas was observed. The

3

4

3

6

.67 (m, 3 H, Ar-H), 6.85–6.87 (m, 4 H, Ar-H), 6.97 (t, JH,H

=

vacuo, and the solid residue was extracted with diethyl ether (2ϫ

70 mL); the solution was cooled to –27 °C to afford brown-violet

3

7

J

.3 Hz, 1 H, Ar-H), 7.01 (t, JH,H = 7.3 Hz, 1 H, Ar-H), 7.19 (d,

3

H,H = 7.1 Hz, 1 H, Ar-H), 7.28 (dt, JH,H = 8.0, JH,H = 1.5 Hz, crystals of 10. Isolated yield 566 mg (64%); m.p. 82–84 °C. (dec.).

3

1

H, Ar-H), 7.31 (d, JP,H = 3.1 Hz, 1 H, CoCH), 7.36 (dd, JH,H

IR (Nujol, KBr): ν˜ = 1577 (m), 1538 [m, ν(C=C)], 937 [s, ρ

1

(PCH

]THF, 300 K): δ = –0.58 (s, 3 H,

), 0.95 (br s, 9 H, PCH ), 6.70 (m,

1 H, Ar-H), 6.87 (m, 1 H, Ar-H), 7.04 (m, 1 H, Ar-H), 7.19–7.24

3

)]

4

–1 1

=

8.0, JH,H = 0.8 Hz, 1 H, Ar-H), 7.38 (m, 1 H, Ar-H), 8.07 (d, cm . H NMR (500 MHz, [D

8

4

13

1

J

P,H = 5.0 Hz, 1 H, NCH) ppm. C{ H} NMR (125 MHz, [D

8

]- Fe–CH

),

3

), 0.47 (br s, 18 H, PCH

3

1

THF, 300 K): δ = 15.9 (d, JP,C = 18.8 Hz, PCH

3

), 38.1 (s, CH

2

5

60.5 (d, JP,C = 11.3 Hz, C=CH

2

), 112.1 (d, JP,C = 3.8 Hz, CH), (m, 3 H, Ar-H), 8.70 (m, 1 H, Ar-H), 9.16 (m, 1 H, Ar-H) ppm.

2

13

1

116.4 (d, JP,C = 47.5 Hz, CH), 118.7 (s, CH), 123.1 (s, CH), 124.9

C{ H} NMR (125 MHz, [D

8

]THF, 300 K): δ = –18.6 (m, Fe–

6

3

1

(s, CH), 126.7 (d, JP,C = 2.5 Hz, CH), 127.8 (d, JP,C = 32.5 Hz, CH

3

), 14.7 (s, PCH

= 16.3 Hz, PCH

P,C = 3.8 Hz, C), 148.4 (s, CH), 150.8 (s, 124.4 (s, CH), 126.8 (s, CH), 127.5 (s, CH), 129.7 (s, CH), 134.3 (s,

3

), 20.1 (d, JP,C = 12.5 Hz, PCH

3

), 20.5 (d, JP,C

3

CH), 128.4 (s, CH), 130.8 (s, CH), 136.2 (s, CH), 142.0 (d, JP,C

.8 Hz, C), 144.1 (d, ⁶

CH), 163.9 (s, C), 165.8 (d, JP,C = 6.3 Hz, C), 199.5 (m, Co–CH)

=

3

), 115.3 (s, CH), 117.8 (s, CH), 121.5 (s, CH),

8

J

5

CH), 139.1 (s, CH), 141.2 (s, C), 151.1 (s, C), 159.3 (s, C), 191.1 (s,

ppm. ³¹P{ H} NMR (202 MHz, [D

1

31

1

8 8

]THF, 203 K): δ = 13.6 (s, 1 P, Fe–C) ppm. P{ H} NMR (202 MHz, [D ]THF, 203 K): cis

2

PCH ) ppm. C29 30CoN P (496.5): calcd. C 70.16, H 6.09, N 5.64,

3

H

2

(10%): δ = 31.3 (d, JP,P = 63.5 Hz, 2 P, PCH

3

), 43.2 (t, JP,P =

2

P 6.24; found C 69.78, H 5.72, N 5.69, P 6.35.

63.5 Hz, 1 P, PCH ) ppm; trans (90%): δ = 17.2 (t, JP,P = 38.2 Hz,

3

2

1

(

7

P, PCH

477.3): calcd. C 57.87, H 8.02, N 2.93, P 19.47; found C 57.43, H

.91, N 2.97, P 19.71.

3 3 3

), 27.9 (d, JP,P = 38.2 Hz, 2 P, PCH ) ppm. C23H38FeNP

2

[

(8-Quinolinyl-κN)ethenyl-η -κC,C](methyl)bis(trimethylphosphane)-

cobalt(I) (8): 8-Vinylquinoline (520 mg, 3.35 mmol) in THF

30 mL) was combined at –80 °C with CoMe(PMe (1.26 g,

.35 mmol) in THF (50 mL). The mixture turned from red to dark

(

3

3 4

)

{(1,8-Naphthalenediyl-κC)[(2-pyridinyl-κN)ethenylidene-η²-

κC,C]}bis(trimethylphosphane)cobalt(I) (11): 2-(2-Naphthalene-1-

ylvinyl)pyridine (750 mg, 3.24 mmol) in diethyl ether (50 mL) was

combined with CoMe(PMe ) (1.22 g, 3.24 mmol) in diethyl ether

3 4

(50 mL) at –70 °C with the evolution of gas. After 16 h at 20 °C,

violet-blue as it warmed and was then kept at 20 °C for 16 h. The

volatiles were removed in vacuo, and the solid residue was extracted

with n-pentane (3ϫ 70 mL). The solution was cooled to –27 °C

to afford dark violet needles of 8, which were suitable for X-ray

Eur. J. Inorg. Chem. 0000, 0–0

13 © 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Job/Unit: I50225

/KAP1

Date: 29-04-15 11:47:37

Pages: 18

www.eurjic.org

FULL PAPER

3

all volatiles were removed from the mixture in vacuo, and the solid

residue was washed with cold n-pentane to afford 11 as red powder.

From a concentrated n-pentane solution at 4 °C, dark red rhombic

crystals suitable for X-ray diffraction were obtained, yield 1.23 g

4.68 (ddd, JP,H = 4.5, ³JP,H = 6.8, ³JH,H = 14.1 Hz, 1 H, C=CH),

3

6.43 (d, JH,H = 7.8 Hz, 1 H, Ar-H), 6.55 (t, JH,H = 6.8 Hz, 1 H,

Ar-H), 6.64 (d, JH,H = 7.4 Hz, 1 H, Ar-H), 6.83 (d, JH,H = 6.0 Hz,

1 H, Ar-H), 6.87 (d, JH,H = 7.0 Hz, 1 H, Ar-H), 7.06 (d, JH,H

7.2 Hz, 1 H, Ar-H), 7.17–7.21 (m, 2 H, Ar-H), 7.31 (d, J

H,H

6.8 Hz, 1 H, Ar-H), 7.52 (d,

C{ H} NMR (125 MHz, [D

17.5 Hz, PCH

3

=

3

(

87%); m.p. 116–119 °C (dec.). IR (Nujol, KBr): ν˜ = 1581 (w), 1565

–1

1

3

[m, (C=C)] cm . H NMR (500 MHz, [D

8

]THF, 300 K): δ = 1.06

J

H,H = 4.8 Hz, 1 H, NCH) ppm.

2

13

1

(

d, JP,H = 6.9 Hz, 9 H, PCH

3

), 1.25 (d, JP,H = 5.8 Hz, 9 H, PCH ),

3

8

]THF, 300 K): δ = 15.3 (d, JP,C

=

3

.01 (ddd, ³JP,H = 4.5, JP,H = 6.8, JH,H = 14.1 Hz, 1 H, C=CH),

3

), 17.1 (d, JP,C = 13.7 Hz, PCH

1

3

), 47.7 (d, JP,C

2

Table 5. Data and structure refinement parameters for 2, 3, 5–9, 11, and 12.

2

3

5

6

7

Empirical formula

Molecular mass

Crystal size [mm]

Crystal system

Space group

a [Å]

b [Å]

c [Å]

α [°]

β [°]

C

467.4

0.50ϫ0.30ϫ0.25

monoclinic

22

H

37CoNP

3

C

392.3

0.40ϫ0.38ϫ0.30

triclinic

15

H

32CoN

2

P

3

C

533.2

0.50ϫ0.40ϫ0.35

monoclinic

20

H

31CoINP2

C

458.1

0.50ϫ0.20ϫ0.20

monoclinic

13

H

26CoIN

2

P

2

C

496.5

0.30ϫ0.30ϫ0.25

orthorhombic

29 2

H30CoN P

¯

P2

1

/n

P1

P2

1

/c

P2

1

/n

1 1 1

P2 2 2

9.0903(5)

23.4947(12)

12.5417(6)

90

101.303(1)

90

2512.2(2)

4

1.236

8.8552(6)

9.8628(7)

13.0630(9)

84.506(1)

76.085(1)

64.835(1)

1002.27(12)

2

9.8825(5)

15.6644(9)

17.3539(10)

90

94.550(1)

90

2678.0(3)

4

1.323

8.8325(6)

13.1611(9)

16.082(1)

90

96.287(1)

90

1858.2(2)

4

1.638

8.8673(7)

10.2926(8)

27.879(2)

90

2544.4(3)

4

1.296

γ [°]

V [Å ]

3

Z

D

calcd. [g/cm³]

1.300

1.092

–

1

μ(Mo-K

α

) [mm ]

0.881

1.916

2.748

0.756

Temperature [K]

Data coll. [°]

h

k

l

Absorption correction

Reflections measured

Unique data

Parameters

GoF on F²

R1 [IՆ2σ(I)]

wR2 (all data)

293(2)

298(2)

3.5Յ2ΘՅ56

–12ՅhՅ12

–31ՅkՅ31

–16ՅlՅ16

semiempirical

29088

3.2Յ2ΘՅ56

–11ՅhՅ11

–13ՅkՅ6

–15ՅlՅ17

semiempirical

6459

3.5Յ2ΘՅ56

–13ՅhՅ13

–20ՅkՅ20

–23ՅlՅ23

semiempirical

36777

4.0Յ2ΘՅ56

–11ՅhՅ11

–17ՅkՅ12

–21ՅlՅ21

semiempirical

11582

4.2Յ2ΘՅ52

–11ՅhՅ10

–12ՅkՅ12

–34ՅlՅ34

semiempirical

16901

6025 (Rint = 0.0362) 4480 (Rint = 0.0121) 6658 (Rint = 0.0228) 4342 (Rint = 0.033) 5187 (Rint = 0.043)

253

1.014

0.0321

0.0930

200

234

172

308

1.035

0.0303

0.0827

1.169

0.0448

0.1683

0.912

0.0344

0.0734

1.064

0.0386

0.0922

8

9

11

12

Empirical formula

Molecular mass

Crystal size [mm]

Crystal system

Space group

a [Å]

b [Å]

c [Å]

α [°]

β [°]

C

381.3

0.50ϫ0.20ϫ0.05

triclinic

18

H

30CoNP

2

C

439.3

0.40ϫ0.20ϫ0.06

monoclinic

20

H

36FeNP

3

C

441.3

0.40ϫ 0.20ϫ0.06

monoclinic

23

H

30CoNP

2

C

469.36

0.50ϫ0.40ϫ0.35

monoclinic

24

H

30CoNOP

2

¯

P1

P2

1

/c

P2

1

/c

1

P2 /c

7.3529(7)

10.8500(11)

13.4218(14)

79.522(2)

79.235(2)

73.633(2)

999.78(17)

2

18.3525(16)

15.4249(14)

16.5084(14)

90

103.068(2)

90

4552.3(7)

8

1.282

9.2353(3)

15.8948(6)

15.5438(6)

90

102.193(1)

90

2230.3(1)

4

1.314

8.3930(4)

14.2682(7)

19.6087(9)

90

90.572(1)

90

2348.08(19)

4

1.328

γ [°]

V [Å ]

3

Z

D

calcd. [g/cm³]

1.267

1.015

–

1

μ(Mo-K

α

) [mm ]

0.877

0.921

0.882

Temperature [K]

Data coll. [°]

h

k

l

Absorption correction

Reflections measured

Unique data

Parameters

GoF on F²

R1 [IՆ2σ(I)]

wR2 (all data)

293(2)

298(2)

3.0Յ2ΘՅ54

–9ՅhՅ9

–13ՅkՅ13

–17ՅlՅ17

semiempirical

11177

4352 (Rint = 0.022)

206

1.045

2.3Յ2ΘՅ56

–24ՅhՅ22

–20ՅkՅ20

–22ՅlՅ22

semiempirical

57200

3.7Յ2ΘՅ56

–12ՅhՅ12

–21ՅkՅ21

–20ՅlՅ20

semiempirical

30443

3.5Յ2ΘՅ56

–11ՅhՅ11

–19ՅkՅ19

–26ՅlՅ26

semiempirical

31948

11345 (Rint = 0.109) 5551 (Rint = 0.027) 5824 (Rint = 0.019)

470

1.091

0.1185

0.4017

250

268

1.045

0.031

0.084

1.039

0.0313

0.0865

0.0329

0.0922

Eur. J. Inorg. Chem. 0000, 0–0

14

Job/Unit: I50225

/KAP1

Date: 29-04-15 11:47:37

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FULL PAPER

3

1

=

6.3 Hz, C=CH), 68.8 (d, ²JP,C = 23.8 Hz, C=CH), 109.4 (d, JP,C

2

ppm. C24H29FeNOP (465.3): calcd. C 61.95, H 6.28, N 3.01; found

C 61.49, H 6.15, N 2.98.

5.0 Hz, CH), 115.9 (s, CH), 116.5 (s, CH), 117.8 (d, ³JP, C

=

5

.0 Hz, CH), 121.8 (s, CH), 122.3 (s, CH), 122.7 (s, CH), 130.8 (s,

X-ray Crystallography: The data were collected at room tempera-

ture with the crystals under argon in glass capillaries; air-stable

specimens were glued to a glass fiber. The data were collected by

using the SMART software with a Bruker AXS SMART APEX

CCD (University of Paderborn) diffractometer and a graphite

3

P,C = 11.3, ³

C), 133.7 (s, CH), 134.6 (dd,

J

JP,C = 5.0 Hz, CH),

3

147.7 (d, JP,C = 6.3 Hz, C), 149.8 (s, C), 151.2 (s, CH), 163.3 (m,

31

1

Co–C), 166.7 (s, NC) ppm. P{ H} NMR (202 MHz, [D

96 K): δ = 2.52 (br s, 1 P, PCH ), 6.79 (br s, 1 P, PCH ) ppm.

30CoNP (441.4): calcd. C 62.59, H 6.85, N 3.17, P 14.04;

found C 62.65, H 6.63, N 3.20, P 14.13.

8

]THF,

[66]

2

C

3

23

H

2

α

monochromator with Mo-K radiation (λ = 0.71073 Å). A sum-

mary of the crystal data, data collection, and structure refinement

is listed in Table 5. The data reductions were performed by using

2

[

(1,8-Naphthalenediyl-κC)[(2-pyridine)ethenylidene-η -κC,C]](carb-

onyl)bis(trimethylphosphane)cobalt(I) (12): A sample of 11 (470 mg,

.06 mmol) in diethyl ether (70 mL) was stirred under 1 bar of car-

[67]

the SAINT software, and the data were corrected for absorption

by using SADABS.^[The structures were solved by direct and

68]

1

[

69]

conventional Fourier methods

and refined by full-matrix least-

bon monoxide for 30 min at 20 °C to form a light yellow precipi-

tate. The volatiles were removed in vacuo, and the solid residue was

extracted with n-pentane (2ϫ 70 mL). A concentrated solution at

–

1

2

squares techniques on F with anisotropic displacement parameters

for the non-hydrogen atoms.^[The hydrogen atoms were refined

at idealized positions riding on their parent atoms with isotropic

displacement parameters Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl).

69]

27 °C afforded orange crystals of 12, yield 354 mg (71%); m.p.

55–157 °C (dec.). IR (Nujol, KBr): ν˜ = 1954 [vs, (CϵO)], 1584

All CH

3

hydrogen atoms were allowed to rotate but not to tip. For

–1 1

8

(m), 1556 [w, (C=C)] cm . H NMR (500 MHz, [D ]THF, 296 K):

5

, one severely disordered pentane solvent molecule was treated

2

3

δ = 0.83 (d, JP,H = 8.5 Hz, 9 H, PCH ), 1.39 (d, JP,H = 7.7 Hz, 9

H, PCH

H, C=CH), 5.01 (dt, JP,H = 5.5, JH,H = 9.4 Hz, 1 H, C=CH), 6.78

[70]

with the SQUEEZE facility of PLATON.

3

4

3

), 3.66 (ddd, JP,H = 5.6, JH,H = 7.2, JH,H = 2.0 Hz, 1

3

CCDC-1031297 (for 2), -1031298 (for 3), -1031299 (for 5), -1031300

(for 6), -1031301(for 7), -1031302 (for 8), -1031303 (for 9), -1031304

(for 11), and -1031305 (for 12) contain the supplementary crystallo-

graphic data for this paper. These data can be obtained free of

charge from The Cambridge Crystallographic Data Centre via

www.ccdc.cam.ac.uk/data_request/cif.

3

4

(ddd, JH,H = 6.1, JH,H = 1.4, JH,H = 1.0 Hz, 1 H, Ar-H), 6.96

3

(

dd, JH,H = 7.2, JH,H = 7.7 Hz, 2 H, Ar-H), 7.17 (dd, JH,H = 7.8,

J

3

H,H = 7.0 Hz, 1 H, Ar-H), 7.13 (m, 2 H, Ar-H), 7.21 (d, JH,H

=

3

6

J

.3 Hz, 1 H, Ar-H), 7.25 (d, JH,H = 8.0 Hz, 1 H, Ar-H), 7.36 (dt,

3

4

H,H = 7.7, JH,H = 2.0 Hz, 1 H, Ar-H), 8.26 (td, JH,H = 0.8, JP,H

13

1

=

8

4.8 Hz, 1 H, NCH) ppm. C{ H} NMR (125 MHz, [D ]THF,

Calculations: Ab initio DFT calculations on 7 were performed with

00 K): δ = 16.9 (d, ¹

J

P, C = 23.9 Hz, PCH

), 17.2 (d,

1

J

=

3

2

9

3

P, C

[71]

the Firey QC package, which is partially based on the GAMESS

2

1.5 Hz, PCH ), 60.5 (d, JP,C = 12.9 Hz, C=CH), 67.9 (d, JP,C

.8 Hz, C=CH), 116.7 (s, CH), 117.3 (s, CH), 117.5 (s, CH), 119.2

3

[72]

[73]

(

US)

its hybrid version by Adamo and Barone

5% exchange and 75% correlation weighting and is known as

PBE0) and the modified three-parameter hybrid functional of

source code, with the PBE1PBE functional,

modied in

[74]

(this functional uses

2

(s, CH), 122.3 (s, CH), 123.4 (s, CH), 123.7 (s, CH), 132.9 (d, JP,C

2

3

=

10.9 Hz, C), 133.1 (d, JP,C = 6.1 Hz, CH), 133.8 (s, CH), 143.8

(s, C), 147.7 (s, CH), 152.0 (s, C), 165.9 (s, NC), 170.1 (m, Co–

[75]

[76]

Becke (B3) with the Lee, Yang, and Parr (LYP) expression for

the nonlocal correlation provided by Perdew and Wang

_B₃_P_W₉₁₎_.[77] Basis functions used the Ahlrichs TZVP basis set

31

1

C), 218.3 (m, Co–CO) ppm. P{ H} NMR (202 MHz, [D

96 K): δ = 12.7 (br m, 2 P, PCH ) ppm. C24 30CoNOP (469.4):

calcd. C 61.41, H 6.44, N 2.98, P 13.20; found C 61.09, H 6.10, N

.93, P 13.54.

8

]THF,

2

3

H

2

(

[78]

triple zeta for valence electrons plus polarization function).

2

Harmonic analysis at the same level of theory (PBE0/TZVP) was

performed for all of the equilibrium geometries to conrm that they

were minima, that is, that there were no imaginary frequencies, on

the potential energy surface (PES). The molecular orbitals, opti-

mized structures, and spin density pictures were created by the

ChemCraft program.^[

[

(1,8-Naphthalenediyl-κC)[(2-pyridinyl-κN)ethenylidene-κC]](carb-

3

onyl)bis(trimethylphosphane)iron(II) (13): A sample of [(κ -C,N,C-

[47b]

C

(

2

6

H

4

–CH=N–C10

30 mL) was stirred under 1 bar of carbon monoxide for 3 h at

0 °C to form an olive green solution. The supernatant solution

was decanted and kept at –27 °C to afford green crystals of 13. The

H

6

)Co(PMe

3

)

3

]

(680 mg, 1.32 mmol) in THF

79]

solid was recrystallized from diethyl ether/THF (1:4). Combined Acknowledgments

yield: 252 mg (41%); m.p. 155–157 °C (dec.). IR (Nujol, KBr): ν˜ =

–

1

(

1

876 [vs, (CϵO)], 1577 (m), 1542 [w, (C=C)] cm . H NMR Financial support of this work by Fonds der Chemischen Industrie

2

4

8

500 MHz, [D ]THF, 300 K): δ = 0.44 (tЈ, | JP,H + JP,H| = 8.1 Hz, is gratefully acknowledged.

8 H, PCH ), 6.56 (dt, JP,H = 4.5, JP,H = 6.8, JH,H = 14.1 Hz, 1

3

H, Ar-H), 6.74 (dd, JP,H = 4.5, JP,H = 6.8, JH,H = 14.1 Hz, 1 H,

Ar-H), 6.95 (dd, JP,H = 4.5, JP,H = 6.8, JH,H = 14.1 Hz, 1 H, Ar-

3

[

1] a) M. Albrecht, Chem. Rev. 2009, 110, 576–623; b) D. A. Colby,

R. G. Bergman, J. A. Ellman, Chem. Rev. 2009, 110, 624–655;

c) J. A. Labinger, J. E. Bercaw, Nature 2002, 417, 507–514; d)

A. E. Shilov, G. B. Shul’pin, Chem. Rev. 1997, 97, 2879–2932;

e) C.-H. Jun, C. W. Moon, D.-Y. Lee, Chem. Eur. J. 2002, 8,

2422–2428; f) I. Omae, Cyclometalation Reactions: Five-Mem-

bered Ring Products as Universal Reagents, Springer, Tokyo,

2014.

3

H), 7.13 (dd, JP,H = 4.5, JP,H = 6.8, JH,H = 14.1 Hz, 1 H, Ar-H),

3

7

.29 (dd, JP,H = 4.5, JP,H = 6.8, JH,H = 14.1 Hz, 1 H, Ar-H), 7.34

dd, JP,H = 4.5, ³JP,H = 6.8, ³JH,H = 14.1 Hz, 1 H, Ar-H), 7.60 (dd,

3

(

3

P,H = 4.5, ³JP,H = 6.8, ³JH,H = 14.1 Hz, 1 H, Ar-H), 8.75 (d, JH,H

3

J

1

3

1

=

3

=

5

8

7.8 Hz, 1 H, NCH) ppm. C{ H} NMR (125 MHz, [D ]THF,

00 K): δ = 13.4 (tЈ, | JP,C + ³JP,C| = 26.3 Hz, PCH

5.0 Hz, CH), 115.9 (s, CH), 116.5 (s, CH), 117.8 (d,

.0 Hz, CH), 121.8 (s, CH), 122.3 (s, CH), 122.7 (s, CH), 130.8 (s,

1

3

), 109.4 (d, JP,C

3

[2] a) D. Vogt, B. Cornils, W. Herrmann, Applied Homogeneous

Catalysis with Organometallic Compounds, volume 1, VCH Ver-

lagsgesellschaft, Weinheim, Germany, 1996; b) P. W. N. M

van Leeuwen, Homogeneous Catalysis: Understanding the Art,

Kluwer Academic, Dordrecht, The Netherlands, 2004; c) F.

Kakiuchi, in: Topics in Organometallic Chemistry, vol. 24: Di-

rected Metallation (Ed.: N. Chatani), Springer, Berlin, 2007, p.

P,C

J =

3

P,C = 11.3, ³

47.7 (d, JP,C = 6.3 Hz, C), 149.8 (s, C), 151.2 (s, CH), 166.7 (s,

NC), 183.3 (m, Fe–C), 211.3 (m, Fe–C), 234.3 (m, Fe–CO) ppm.

C), 133.7 (s, CH), 134.6 (dd,

1

J

JP,C = 5.0 Hz, CH),

3

31

1

8 3

P{ H} NMR (202 MHz, [D ]THF, 203 K): δ = 21.1 (s, 2 P, PCH )

Eur. J. Inorg. Chem. 0000, 0–0

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www.eurjic.org

FULL PAPER

1

–33; d) H. U. Blaser, E. Schmidt (Eds.), Asymmetric Catalysis

Calvet, M. Font-Bardía, J. Organomet. Chem. 2009, 694, 2467–

2475; f) L. Keyes, T. Wang, B. O. Patrick, J. A. Love, Inorg.

Chim. Acta 2012, 380, 284–290.

on Industrial Scale: Challenges, Approaches and Solutions,

Wiley-VCH, Weinheim, Germany, 2011.

[

3] a) P.-S. Lee, T. Fujita, N. Yoshikai, J. Am. Chem. Soc. 2011, [17] M. Martín, E. Sola, S. Tejero, J. L. Andrés, L. A. Oro, Chem.

1

2

8

33, 17283–17295; b) K. Gao, N. Yoshikai, Acc. Chem. Res.

014, 47, 1208–1219; c) L. Ackermann, J. Org. Chem. 2014, 79,

948–8954; d) D. Tilly, G. Dayaker, P. Bachu, Catal. Sci. Tech-

Eur. J. 2006, 12, 4043–4056.

[18] G. R. Newkome, K. J. Theriot, B. K. Cheskin, D. W. Evans,

G. R. Baker, Organometallics 1990, 9, 1375–1379.

[19] A. G. Wong-Foy, L. M. Henling, M. Day, J. A. Labinger, J. E.

Bercaw, J. Mol. Catal. A 2002, 189, 3–16.

nol. 2014, 4, 2756–2777.

[

4] I. Omae, Coord. Chem. Rev. 2004, 248, 995–1023.

5] a) G. Dyker, Handbook of C–H transformations: Applications,

in: Organic Synthesis vol. 2, Wiley-VCH, Weinheim, Germany,

[20] a) R. Castro-Rodrigo, M. A. Esteruelas, S. Fuertes, A. M.

López, S. Mozo, E. Oñate, Organometallics 2009, 28, 5941–

5951; b) B. Eguillor, M. A. Esteruelas, M. Oliván, E. Oñate,

Organometallics 2005, 24, 1428–1438.

[21] a) L. Zhang, L. Dang, T. B. Wen, H. H. Y. Sung, I. D. Wil-

liams, Z. Lin, G. Jia, Organometallics 2007, 26, 2849–2860; b)

J. N. Coalter, W. E. Streib, K. G. Caulton, Inorg. Chem. 2000,

39, 3749–3756; c) M. L. Buil, M. A. Esteruelas, E. Goni, M.

Oliván, E. Oñate, Organometallics 2006, 25, 3076–3083.

[22] J. Navarro, E. Sola, M. Martín, I. T. Dobrinovitch, F. J. Lahoz,

L. A. Oro, Organometallics 2004, 23, 1908–1917.

2

005; b) J. Tsuji, Transition Metal Reagents and Catalysts, John

Wiley & Sons, Chichester, UK, 2000; c) I. Omae, Appl. Or-

ganomet. Chem. 2009, 23, 91–107.

[

6] a) M. Hanif, Z. H. Chohan, Appl. Organomet. Chem. 2013, 27,

3

6–44; b) S. Blanck, T. Cruchter, A. Vultur, R. Riedel, K.

Harms, M. Herlyn, E. Meggers, Organometallics 2011, 30,

4598–4606; c) C. G. Hartinger, P. J. Dyson, Chem. Soc. Rev.

2

009, 38, 391–401; d) S. M. Meier, M. Hanif, Z. Adhireksan,

V. Pichler, M. Novak, E. Jirkovsky, M. A. Jakupec, V. B. Arion,

C. A. Davey, B. K. Keppler, C. G. Hartinger, Chem. Sci. 2013,

[23] M. A. Cinellu, F. Cocco, G. Minghetti, S. Stoccoro, A. Zucca,

M. Manassero, J. Organomet. Chem. 2009, 694, 2949–2955.

[24] T. Kobayashi, H. Yorimitsu, K. Oshima, Chem. Asian J. 2011,

6, 669–673.

[25] S. Oi, K. Sakai, Y. Inoue, Org. Lett. 2005, 7, 4009–4011.

[26] a) G. Jia, D. W. Meek, J. C. Gallucci, Organometallics 1990,

9, 2549–2555; b) O. V. Ozerov, M. Pink, L. A. Watson, K. G.

Caulton, J. Am. Chem. Soc. 2004, 126, 2105–2113.

[27] C. P. Lenges, M. Brookhart, B. E. Grant, J. Organomet. Chem.

1997, 528, 199–203.

[28] a) H.-F. Klein, H. H. Karsch, Chem. Ber. 1975, 108, 944–955;

b) M. Gass, Ph. D. Thesis, Darmstadt University of Technol-

ogy, Germany, 1988; c) J. R. Bleeke, B. L. Lutes, M. Lipschutz,

D. Sakellariou-Thompson, J. S. Lee, N. P. Rath, Organometal-

lics 2010, 29, 5057–5067.

4, 1837–1846; e) R. Breslow (Ed.), Artificial Enzymes, Wiley-

VCH, Weinheim, Germany, 2006.

7] a) W.-Y. Wong, Z. He, S.-K. So, K.-L. Tong, Z. Lin, Organome-

tallics 2005, 24, 4079–4082; b) F. Gao, Y. Wang, D. Shi, J.

Zhang, M. Wang, X. Jing, R. Humphry-Baker, P. Wang, S. M.

Zakeeruddin, M. Grätzel, J. Am. Chem. Soc. 2008, 130, 10720–

1

0728; c) G. Ge, J. He, H. Guo, F. Wang, D. Zou, J. Organomet.

Chem. 2009, 694, 3050–3057.

[

8] G. Zhou, W.-Y. Wong, X. Yang, Chem. Asian J. 2011, 6, 1706–

1727.

9] a) L. Ilies, J. Okabe, N. Yoshikai, E. Nakamura, Org. Lett.

2

010, 12, 2838–2840; b) L. Ilies, S. Asako, E. Nakamura, J.

Am. Chem. Soc. 2011, 133, 7672–7675.

[

10] a) R. M. (Ed.) Bullock, Catalysis without Precious Metals,

Wiley-VCH, Weinheim, Germany, 2010; b) R. B. King (Ed.),

Encyclopedia of Inorganic Chemistry, John Wiley, Chichester,

UK, 1994.

11] J. Hagen, Industrial Catalysis: A Practical Approach, Wiley-

VCH, Weinheim, Germany, 2006.

[

29] A. W. Addison, T. N. Rao, J. Reedijk, J. van Rijn, G. C. Ver-

schoor, J. Chem. Soc., Dalton Trans. 1984, 1349–1356.

[

30] J.-P. Djukic, W. Iali, A. Hijazi, L. Ricard, J. Organomet. Chem.

2

011, 696, 2101–2107.

[

31] F. H. Allen, Acta Crystallogr., Sect. A 2002, 58, 380–388.

32] a) H. Xu, W. H. Bernskoetter, J. Am. Chem. Soc. 2011, 133,

12] a) R. Beck, M. Frey, S. Camadanli, H.-F. Klein, Dalton Trans.

14956–14959; b) H. Xu, P. G. Williard, W. H. Bernskoetter, Or-

2008, 4981–4983; b) R. Beck, H. Sun, X. Li, H.-F. Klein, Z.

ganometallics 2013, 32, 798–806.

Anorg. Allg. Chem. 2009, 635, 99–105; c) R. Beck, U. Flörke,

H.-F. Klein, Inorg. Chem. 2009, 48, 1416–1422; d) S. Camad-

anli, R. Beck, U. Flörke, H.-F. Klein, Dalton Trans. 2008,

[

33] R. Beck, H.-F. Klein, Z. Anorg. Allg. Chem. 2008, 634, 1971–

1974.

34] H. F. Klein, H. H. Karsch, Inorg. Chem. 1975, 14, 473–477.

5701–5704; e) R. Beck, H. Sun, X. Li, S. Camadanli, H.-F.

Klein, Eur. J. Inorg. Chem. 2008, 3253–3257; f) R. Beck, T.

Zheng, H. Sun, X. Li, U. Flörke, H.-F. Klein, J. Organomet.

Chem. 2008, 693, 3471–3478.

[35] S. W. Kohl, F. W. Heinemann, M. Hummert, H. Weißhoff, A.

Grohmann, Eur. J. Inorg. Chem. 2006, 3901–3910.

[36] A. G. Orpen, L. Brammer, F. H. Allen, O. Kennard, D. G. Wat-

son, R. Taylor, J. Chem. Soc., Dalton Trans. 1989, S1–S83.

[37] Y. Yu, J. M. Smith, C. J. Flaschenriem, P. L. Holland, Inorg.

Chem. 2006, 45, 5742–5751.

[38] M. A. Esteruelas, F. J. Fernández-Alvarez, M. Oliván, E.

Oñate, J. Am. Chem. Soc. 2006, 128, 4596–4597.

[39] H.-F. Klein, R. Beck, U. Flörke, H.-J. Haupt, Eur. J. Inorg.

Chem. 2003, 1380–1387.

[40] a) P. Barrio, M. A. Esteruelas, E. Oñate, Organometallics 2004,

23, 3627–3639; b) F. Ortega-Jiménez, M. C. Ortega-Alfaro,

J. G. López-Cortés, R. Gutiérrez-Pérez, R. A. Toscano, L. Vel-

asco-Ibarra, E. Peña-Cabrera, C. Alvarez-Toledano, Organo-

metallics 2000, 19, 4127–4133.

[41] P. W. N. M. van Leeuwen, Homogeneous Catalysis, Kluwer Ac-

ademic, Dordrecht, The Netherlands, 2004, p. 1–19.

[42] a) J. Foerstner, A. Kakoschke, R. Goddard, J. Rust, R. Wart-

chow, H. Butenschön, J. Organomet. Chem. 2001, 617–618,

412–422; b) H. Wadepohl, W. Galm, H. Pritzkow, A. Wolf,

Chem. Eur. J. 1996, 2, 1453–1465.

[

13] S. Camadanli, R. Beck, U. Flörke, H.-F. Klein, Organometallics

2009, 28, 2300–2310.

14] H.-F. Klein, S. Camadanli, R. Beck, D. Leukel, U. Flörke, An-

gew. Chem. Int. Ed. 2005, 44, 975–977; Angew. Chem. 2005,

117, 997.

[

15] a) K. R. Flower, V. J. Howard, R. G. Pritchard, J. E. Warren,

Organometallics 2002, 21, 1184–1189; b) K. R. Flower, L. G.

Leal, R. G. Pritchard, J. Organomet. Chem. 2005, 690, 3390–

3396; c) K. R. Flower, R. G. Pritchard, J. E. Warren, Eur. J.

Inorg. Chem. 2003, 1929–1938; d) B. Li, T. Roisnel, C. Darcel,

P. H. Dixneuf, Dalton Trans. 2012, 41, 10934–10937; e) K. A.

Azam, D. W. Bennett, M. R. Hassan, D. T. Haworth, G. Ho-

garth, S. E. Kabir, S. V. Lindeman, L. Salassa, S. R. Simi, T. A.

Siddiquee, Organometallics 2008, 27, 5163–5166.

[

16] a) M. Crespo, C. M. Anderson, N. Kfoury, M. Font-Bardía, T.

Calvet, Organometallics 2012, 31, 4401–4404; b) R. Martín, M.

Crespo, M. Font-Bardía, T. Calvet, Organometallics 2008, 28,

587–597; c) M. Crespo, M. Font-Bardía, X. Solans, J. Or-

ganomet. Chem. 2006, 691, 444–454; d) M. Crespo, X. Solans,

M. Font-Bardía, Organometallics 1995, 14, 355–364; e) J.

Rodríguez, J. Zafrilla, J. Albert, M. Crespo, J. Granell, T.

[43] M. Barbasiewicz, A. Szadkowska, R. Bujok, K. Grela, Organo-

metallics 2006, 25, 3599–3604.

[44] H. J. Reich, J. Chem. Educ. 1995, 72, 1086.

Eur. J. Inorg. Chem. 0000, 0–0

16

Job/Unit: I50225

/KAP1

Date: 29-04-15 11:47:37

Pages: 18

www.eurjic.org

FULL PAPER

[

45] G. R. Fulmer, A. J. M. Miller, N. H. Sherden, H. E. Gottlieb,

J. Kłak, Polyhedron 2005, 24, 3012–3021; k) J. Matthes, S.

Gründemann, A. Toner, Y. Guari, B. Donnadieu, J. Spandl, S.

Sabo-Etienne, E. Clot, H.-H. Limbach, B. Chaudret, Organo-

metallics 2004, 23, 1424–1433.

A. Nudelman, B. M. Stoltz, J. E. Bercaw, K. I. Goldberg, Orga-

nometallics 2010, 29, 2176–2179.

46] a) S. I. Kozhushkov, J. Foerstner, A. Kakoschke, D. Stellfeldt,

L. Yong, R. Wartchow, A. de Meijere, H. Butenschön, Chem.

Eur. J. 2006, 12, 5642–5647; b) H.-F. Klein, R. Beck, U. Flörke,

H.-J. Haupt, Eur. J. Inorg. Chem. 2002, 3305–3312; c) S. De-

blon, L. Liesum, J. Harmer, H. Schönberg, A. Schweiger, H.

Grützmacher, Chem. Eur. J. 2002, 8, 601–611.

[58] A. Díez, J. Forniés, A. García, E. Lalinde, M. T. Moreno, In-

org. Chem. 2005, 44, 2443–2453.

[59] S. Camadanli, Ph. D. Thesis, Darmstadt University of Technol-

ogy, Germany, 2005.

[60] a) C. Zucchi, A. Cornia, R. Boese, E. Kleinpeter, H. Alper, G.

Pályi, J. Organomet. Chem. 1999, 586, 61–69; b) H. Alper, L.

Bencze, R. Boese, L. Caglioti, R. Kurdi, G. Pályi, S. Tiddia, D.

Turrini, C. Zucchi, J. Mol. Catal. A 2003, 204–205, 227–233;

c) C. Zucchi, R. Boese, K. Alberts, T. Herbrich, G. Tóth, L.

Bencze, G. Pályi, Eur. J. Inorg. Chem. 2001, 2297–2304.

[61] a) C. Ni, P. P. Power, Chem. Commun. 2009, 5543–5545; b) D.

Benito-Garagorri, I. Lagoja, L. F. Veiros, K. A. Kirchner, Dal-

ton Trans. 2011, 40, 4778–4792.

[47] a) E. R. Bartholomew, E. C. Volpe, P. T. Wolczanski, E. B.

Lobkovsky, T. R. Cundari, J. Am. Chem. Soc. 2013, 135, 3511–

3

527; b) H.-F. Klein, S. Camadanli, R. Beck, U. Flörke, Chem.

Commun. 2005, 381–382.

[

48] E. C. Volpe, P. T. Wolczanski, J. M. Darmon, E. B. Lobkovsky,

Polyhedron 2013, 52, 406–415.

49] D. G. Johnson, J. M. Lynam, N. S. Mistry, J. M. Slattery, R. J.

Thatcher, A. C. Whitwood, J. Am. Chem. Soc. 2012, 135, 2222–

2

234.

50] R. Beck, U. Flörke, H.-F. Klein, Inorg. Chim. Acta 2009, 362,

984–1990.

51] C. M. Anderson, M. Crespo, N. Kfoury, M. A. Weinstein, J. M.

Tanski, Organometallics 2013, 32, 4199–4207.

52] E. C. Volpe, P. T. Wolczanski, E. B. Lobkovsky, Organometal-

lics 2009, 29, 364–377.

53] M. Brookhart, W. A. Chandler, A. C. Pfister, C. C. Santini,

P. S. White, Organometallics 1992, 11, 1263–1274.

54] H. Schaeufele, D. Hu, H. Pritzkow, U. Zenneck, Organometal-

lics 1989, 8, 396–401.

55] a) W. W. Brennessel, R. E. Jilek, J. E. Ellis, Angew. Chem. Int.

Ed. 2007, 46, 6132–6136; Angew. Chem. 2007, 119, 6244; b) E.-

M. Schnöckelborg, M. M. Khusniyarov, B. de Bruin, F. Hartl,

T. Langer, M. Eul, S. Schulz, R. Pöttgen, R. Wolf, Inorg. Chem.

[62] H. H. Karsch, Chem. Ber. 1977, 110, 2699–2711.

[63] W. Wolfsberger, H. Schmidbaur, Synth. React. Inorg. Met.-Org.

Chem. 1974, 4, 149–156.

[

1

[64] E. W. Turnblom, T. J. Katz, J. Am. Chem. Soc. 1973, 95, 4292–

4311.

[65] a) C. J. Cavallito, H. S. Yun, J. C. Smith, F. F. Foldes, J. Med.

Chem. 1969, 12, 134–138; b) M. J. Percino, V. Chapela, M.

Salmón, G. Espinosa-Pérez, A. Herrera, A. Flores, J. Chem.

Crystallogr. 1997, 27, 549–552.

[66] SMART, Molecular Analysis Research Tool, Bruker AXS Inc.,

Madison, WI, 2001.

[67] SAINTPlus, Data Reduction and Correction Program, Bruker

AXS Inc., Madison, WI, 2001.

[68] SADABS, An Empirical Absorption Correction Program,

Bruker AXS Inc, Madison, WI, 2001.

[69] G. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112–122.

2

012, 51, 6719–6730.

[56] G. Zhu, J. M. Tanski, D. G. Churchill, K. E. Janak, G. Parkin, [70] A. Spek, J. Appl. Crystallogr. 2003, 36, 7–13.

J. Am. Chem. Soc. 2002, 124, 13658–13659.

[71] A. A. Granovsky, Firey, version 7.1.G; http://classic.-

[57] a) A. R. Dick, J. W. Kampf, M. S. Sanford, Organometallics

chem.msu.su/gran/–gamess/index.html.

2

005, 24, 482–485; b) N. Godbert, T. Pugliese, I. Aiello, A.

Bellusci, A. Crispini, M. Ghedini, Eur. J. Inorg. Chem. 2007,

105–5111; c) D. E. Janzen, D. G. VanDerveer, L. F. Mehne,

D. A. da Silva Filho, J.-L. Bredas, G. J. Grant, Dalton Trans.

008, 1872–1882; d) J. R. Berenguer, J. Fernández, N. Giménez,

E. Lalinde, M. T. Moreno, S. Sánchez, Organometallics 2013,

2, 3943–3953; e) J. L. Serrano, L. García, J. Pérez, E. Pérez,

[72] M. W. Schmidt, K. K. Baldridge, J. A. Boatz, S. T. Elbert,

M. S. Gordon, J. H. Jensen, S. Koseki, N. Matsunaga, K. A.

Nguyen, S. Su, T. L. Windus, M. Dupuis, J. A. Montgomery,

J. Comput. Chem. 1993, 14, 1347–1363.

5

2

[73] J. P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett. 1996,

77, 3865–3868.

3

[74] C. Adamo, V. Barone, J. Chem. Phys. 1999, 110, 6158–6170.

J. García, G. Sánchez, G. López, M. Liu, Eur. J. Inorg. Chem. [75] A. D. Becke, J. Chem. Phys. 1993, 98, 5648–5652.

2

008, 4797–4806; f) G. Sánchez, J. García, D. Meseguer, J. L.

Serrano, L. García, J. Pérez, G. López, Dalton Trans. 2003,

709–4717; g) M. A. Esteruelas, F. J. Fernández-Alvarez, M.

[76] C. Lee, W. Yang, R. G. Parr, Phys. Rev. B 1988, 37, 785–789.

[77] J. P. Perdew, Y. Wang, Phys. Rev. B 1992, 45, 13244–13249.

[78] A. Schäfer, C. Huber, R. Ahlrichs, J. Chem. Phys. 1994, 100,

5829–5835.

[79] G. A. Zhurko, ChemCraft, version 1.7 build 382; http://

www.chemcraftprog.-com.

4

Oliván, E. Oñate, Organometallics 2009, 28, 2276–2284; h) T.

Dubé, J. W. Faller, R. H. Crabtree, Inorg. Chem. 2002, 41,

5

561–5565; i) D.-H. Lee, H. J. Kwon, B. P. Patel, L. M. Liable-

Sands, A. L. Rheingold, R. H. Crabtree, Organometallics 1999,

8, 1615–1621; j) J. G. Małecki, M. Jaworska, R. Kruszynski,

Received: March 1, 2015

1

Published Online: ᭿

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FULL PAPER

Cyclometalated Compounds

R. Beck,* S. Camadanli, U. Flörke,

H.-F. Klein ...................................... 1–18

Reactivity Diversification – Synthesis and

Exchange Reactions of Cobalt and Iron 2-

Alkenylpyridine/-pyrazine Complexes Ob-

2

tained by Vinylic C(sp )–H Activation

Keywords: C–H activation / Cyclometal-

ation / Cobalt / Iron / Nitrogen heterocycles

The regioselective cyclometalation reac-

tions of 2-alkenylpyridine/-pyrazine deriva-

iodomethane but readily demetalate with

carbon monoxide. Conversely, reductive

elimination through the release of

ethaneisthedominantreactionwiththesame

3

tives with Co(CH )(PMe

3

)

4

2

provide cobalt

complexes by vinylic C(sp )–H activation.

These cobalt complexes smoothly add

3 2 3 4

ligands and Fe(CH ) (PMe ) .

Eur. J. Inorg. Chem. 0000, 0–0

18

Article Doi

Reactivity Diversification - Synthesis and Exchange Reactions of Cobalt and Iron 2-Alkenylpyridine/-pyrazine Complexes Obtained by Vinylic C(sp2)-H Activation

DOI: 10.1002/ejic.201500225

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Article abstract of DOI:10.1002/ejic.201500225

Full text of DOI:10.1002/ejic.201500225

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