Ionic and covalent mixed-metal complexes by reaction of transition metal M-H acids (M = Mo, Mn, Fe, Co) with [Ir(PMe3)4CH 3] or [Rh(PMe3)3CH3] and structurally related Rh-M and Ir-M heterobimetallics (M = Mn, Fe, Ru)

Article abstract of DOI:10.1016/S0020-1693(02)01536-0

Treatment of [Ir(PMe₃)₄CH₃] with equimolar quantities of the carbonyl hydrides [M(CO)_nH] (M=Mn, Co; n=5, 4) or [CpM(CO)_nH] (M=Mo, Fe; n=3, 2) resulted in clean protonation of the d⁸ substrate producing cis-[Ir(PMe ₃)₄(H)(CH₃)][X], where X^-=[Mn(CO) ₅]^- (1), [Co(CO)₄]^- (2), [CpMo(CO)₃]^- (3), and [CpFe(CO)₂]^- (4), respectively. Combination of [Rh(PMe₃)₃CH ₃] with [Mn(CO)₅H] furnished [(Me₃P) ₃Rh(μ-CO)₂Mn(CO)₃PMe₃] (5), which was also isolated from the salt elimination reaction between [Rh(PMe ₃)₄]Cl and Na[Mn(CO)₅]. [(Me₃P) ₂Rh(μ-CO)₂Fe(PMe₃)Cp] (6), [(Me ₃P)₃Ir(μ-CO)₂Fe(PMe₃)Cp] (7), and [(Me₃P)₃Ir(μ-CO)₂Ru(PMe₃)Cp] (8) were obtained similarly by reacting [Rh(PMe₃)₄]Cl or [Ir(PMe₃)₄]Cl with the potassium salts K[CpM(CO) ₂] (M=Fe, Ru). The crystal structure analysis of 3 demonstrates that in the solid state the hexacoordinate [Ir(PMe₃)₄(H) (CH₃)]⁺ cation and its [CpMo(CO)₃]^- counterion exist as well-separated ion pairs. The structures of 5-8 comprise (Me₃P)_nRh (n=3, 2) or (Me₃P)₃Ir groups attached to Mn(CO)₃PMe₃ or M(PMe₃)Cp fragments (M=Fe, Ru) by doubly carbonyl-bridged metal-metal bonds of normal length: Rh-Mn, 2.6695(14); Rh-Fe, 2.5748(6); Ir-Fe, 2.6470(7); Ir-Ru, 2.7348(14) A?.

Full text of DOI:10.1016/S0020-1693(02)01536-0

Inorganica Chimica Acta 350 (2003) 77ꢃ85
/
www.elsevier.com/locate/ica
Ionic and covalent mixed-metal complexes by reaction of transition
metal Mꢀ
/
H acids (Mꢀ
/
Mo, Mn, Fe, Co) with [Ir(PMe ) CH ] or
3
3
4
[
Rh(PMe ) CH ] and structurally related Rhꢀ
/
M and Irꢀ
/
M
3
3
3
heterobimetallics (Mꢀ
/
Mn, Fe, Ru)
Lutz Dahlenburg *, Roland Hache
Institut f u¨ r Anorganische Chemie der Universit a¨ t Erlangen-N u¨ rnberg, Egerlandstraße 1, D-91058 Erlangen, Germany
Received 2 May 2002; accepted 30 July 2002
Dedicated to Professor Dr. Pierre Braunstein.
Abstract
Treatment of [Ir(PMe
3
)
4
CH
3
] with equimolar quantities of the carbonyl hydrides [M(CO)
n
H] (Mꢀ
/
Mn, Co; nꢀ
/
5, 4) or
8
3, 2) resulted in clean protonation of the d substrate producing cis-[Ir(PMe ) (H)(CH )][X],
[
where X
CpM(CO) H] (MꢀMo, Fe; nꢀ
/
/
n
ꢁ
3 4
3
ꢁ
ꢁ
ꢁ
ꢁ
ꢀ
3
/
[Mn(CO)
5
]
(1), [Co(CO)
CH ] with [Mn(CO) H] furnished [(Me
4
]
(2), [CpMo(CO)
3
]
(3), and [CpFe(CO)
2
]
(4), respectively. Combination of
Mn(CO) PMe ] (5), which was also isolated from the salt
[
Rh(PMe
3
)
3
5
3
P)
3
Rh(m-CO)
2
3
3
elimination reaction between [Rh(PMe ) ]Cl and Na[Mn(CO) ]. [(Me P) Rh(m-CO) Fe(PMe )Cp] (6), [(Me P) Ir(m-CO) Fe(P-
3
4
5
3
2
2
3
3
3
2
Me
potassium salts K[CpM(CO)
hexacoordinate [Ir(PMe (H)(CH
8 comprise (Me P) Rh (nꢀ3, 2) or (Me P) Ir groups attached to Mn(CO) PMe or M(PMe )Cp fragments (Mꢀ
3
)Cp] (7), and [(Me
3
P)
3
Ir(m-CO)
2
Ru(PMe
3
)Cp] (8) were obtained similarly by reacting [Rh(PMe
3
)
4
]Cl or [Ir(PMe
3
)
4
]Cl with the
2
] (MꢀFe, Ru). The crystal structure analysis of 3 demonstrates that in the solid state the
/
ꢂ
ꢁ
3
)
4
3
)] cation and its [CpMo(CO)
3
]
counterion exist as well-separated ion pairs. The structures of
Fe, Ru) by
Fe, 2.6470(7); IrꢀRu,
5
ꢃ
/
/
/
3
n
3
3
3
3
3
doubly carbonyl-bridged metalꢀ
/
metal bonds of normal length: Rhꢀ
/
Mn, 2.6695(14); Rhꢀ
/
Fe, 2.5748(6); Irꢀ
/
/
˚
.7348(14) A.
2
#
2003 Elsevier Science B.V. All rights reserved.
Keywords: Oxidative addition; Alkylhydrido complexes; Metalꢀmetal bonds; Heterobimetallic complexes; X-ray structures analysis
/
1
. Introduction
metalꢀ
/
metal-bonded heterobimetallics with concomi-
tant loss of HX. Illustrative examples include the
While Eꢀ
/
H acids of the main group elements with
formation of [CpW(CO) Re(CO) (diars)], [CpM(CO)(m-
3
3
bond polarities as disparate as Cꢀ
/
H and ClꢀH are well
/
CO) M?(PPh ) ] (Mꢀ
/
Cr, Mo, W; M?ꢀRh, Ir) or
/
2
3 2
known for their aptitude to oxidatively add to coordi-
natively unsaturated complexes of e.g., Rh(I), Ir(I) or
[CpMo(CO) Co(CO) ] in the reactions occurring be-
3
4
tween the Mꢀ
/
H acids [CpM(CO) H] [3] and either
3
Pt(0) [1], analogous Mꢀ
/
H additions of Brønsted-acidic
[Re(CO) (diars)OCH ] [4], [Rh (PPh ) (m-OH) ] [5a],
3
3
2
3 4
2
transition metal hydrides [2] are less well documented.
Combination of acidic metal carbonyl hydrides or
dihydrides, [M(CO) H ] or [CpM(CO) H ], with low-
[Ir(CO)(PPh ) CH ] [6], or [Co(CO) X] (Xꢀ
/
Co(CO)4,
Mn(CO) PBu ) [7]. ‘Neutralization’ of the dinuclear
3
2
3
4
4
3
n
m
n
m
palladium hydroxide [Pd (PPh ) (C H ) (m-OH) ] by
2
3 2
6
5 2
2
valent metal complexes [L M?X] typically leads to
acidic transition metal hydrides, [CpM(CO) H], simi-
larly afforded heterotrimetallic clusters, [Pd (PPh ) -
n
3
2
3 2
(
C H ) (m-OH)(m-CO) (m -CO)MCp] (Mꢀ
/
Cr, Mo,
W), along with water [5b]. The obvious inference to be
drawn for the isolation of MꢀH addition products is
that the use of coordinatively unsaturated substrate
6
5 2
2
3
*
52 7387.
Corresponding author. Tel.: ꢂ
/
49-9131-852 7353; fax: ꢂ
/
49-9131-
(L.
8
/
E-mail
address:
dahlenburg@chemie.uni-erlangen.de
Dahlenburg).
0020-1693/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(02)01536-0

78
L. Dahlenburg, R. Hache / Inorganica Chimica Acta 350 (2003) 77ꢃ85
/
complexes which have no X ligands and/or form
particularly strong metal-to-hydrogen bonds might
lead to stable complexes directly resulting from
2.2. Metal complexes
2.2.1. [Ir(PMe ) (H)(CH )][Mn(CO) ] (1)
A solution of [Mn(CO) H], generated by treating
3
4
3
5
[
That this is correct is evident from the smooth forma-
M(CO) H ] or [CpM(CO) H ] oxidative addition.
n
m
n
m
5
[Ph PNPPh ][Mn(CO)] (435 mg, 0.59 mmol) with the
3
3
5
tion of [CpRe(CO) (m-H)Pt(PPh ) H] [8] and [CpMo-
stoichiometrically required amount of CF SO H in 30
3
2
3 2
3
(
CO) Pt(PPh ) H] [9] from [Pt(C H )(PPh ) ] and either
ml of pentane [22], was filtered over Celite and subse-
quently condensed in vacuo onto a nitrogen-cooled
frozen mixture of [Ir(PMe ) CH ] (210 mg, 0.41 mmol)
3
3 2
2
4
3 2
[
CpRe(CO) H ] or [CpMo(CO) H]. Moreover, treat-
2 2 3
ment of the iridium chelate complex [Ir{t-
BuP(CH CH CH PPh ) }Cl] with equimolar [CpM-
3
4
3
and n-C H (10 ml). Warming to ambient temperature
12
2
2
2
2 2
5
(
the d substrate producing [Ir{t-BuP(CH CH CH -
CO) H] (Mꢀ
/
Mo, W) leads to clean protonation of
with stirring caused the formation of a pale yellow
solution together with a colorless precipitate, which was
filtered off and thoroughly washed with pentane.
3
8
2
2
2
PPh ) }(H)(Cl)][CpM(CO) ], as shown in a previous
2
2
3
communication from this laboratory [10]. The latter
reaction, which at least in part is driven by the distinct
stability of hydridoiridium(III) complexes, appears to
depend critically on the electron richness of the Ir(I)
substrate complex: While no reaction whatsoever occurs
between either [CpMo(CO) H] or [CpW(CO) H] and
Crystallization from acetonitrile/diethyl ether at ꢁ
20 8C afforded 75 mg (26%) of 1 as colorless to pale
/
yellow needles.*IR (Nujol): 1869, 1905 (CO), 2035
/
ꢁ
1
(IrH) cm ; (CH CN): 1850, 1898 cm
ꢁ1
1
(CO).*
/
H
138,
3
2
NMR (CD CN): dꢀ
/
ꢁ
/
13.31 (dq, trans- J(P,H)ꢀ
/
3
2
cis- J(P,H)ꢀ
not resolved),
J(P,H)ꢀ4, cis- J(P,H)ꢀ
J(P,H)ꢀ Hz; P(CH ) ), 1.59 (X AA?X
SJ(P,H)ꢀ
/
20 Hz; IrH; hydride-to-methyl coupling
3
3
3
3
trans-[Ir(CO)(PPh ) Cl] [6], proton transfer from the
3
ꢁ
/
0.01 (ddq; J(H,H)$
/
1, trans- -
Hz; IrCH3), 1.44 (d,
-t,
2
3
Moꢀ
/
H or the Wꢀ/H bond to iridium can be induced
/
/8
2
readily by substituting additional P donor groups for
CO as has been demonstrated for the [Ir{t-
BuP(CH CH CH PPh ) }Cl]/[CpM(CO) H] systems in-
/8
1
?
9
3
3
9
/
7 Hz; 2 P(CH ) , mutually trans), 1.65 (d,
3
3
2
31
1
J(P,H)ꢀ
/
8 Hz; 1 P(CH ) ).*
/
P{ H} NMR (DMF-
2
2
2
2 2
3
3 3
2
vestigated earlier [10] and is confirmed further for
several [Ir(PMe ) CH ]/[M(CO) H] (MꢀMn, Co; nꢀ
, 4) and [Ir(PMe ) CH ]/[CpM(CO) H] (MꢀMo, Fe;
3, 2) pairs to be described below. For comparative
d7): dꢀ
/
ꢁ
/
67.9, ꢁ
/
67.3 (ABX m, cis- J(P , P )ꢀ
/
18
52.6 (ABX t,
2
A
B
/
/
Hz; 2 P(CH ) , trans to H and CH ), ꢁ
/
3
4
3
n
3 3
3
2
2
2
5
/
jcis- J(P , P )ꢂ
/
cis- J(P , P )jꢀ
/
38 Hz; 2 P(CH3)3,
Anal. Found: C, 30.38; H, 6.17. Calc.
for C H IrMnO P (707.52): C, 30.56; H, 5.70%.
3
4
3
n
A
X
B
X
nꢀ
/
mutually trans).*
/
purposes, the reactivity of the methylrhodium com-
pound [Rh(PMe ) CH ] toward [Mn(CO) H] was also
1
8
40
5 4
3
3
3
5
studied, as were some salt elimination reactions of
Na[Mn(CO) ] and K[CpM(CO) ] (MꢀFe, Ru) with
Rh(PMe ) ]Cl and [Ir(PMe ) ]Cl, respectively.
2.2.2. [Ir(PMe ) (H)(CH )][Co(CO) ] (2)
3 4 3 4
/
A procedure analogous to that for 1 was employed,
using 435 mg (0.61 mmol) of [Ph PNPPh ][Co(CO) ]
5
2
[
3
4
3 4
3
3
4
together with 50.0 ml of triflic acid in petroleum ether (10
ml) and 185 mg (0.36 mmol) of [Ir(PMe ) CH ] in 10 ml
3
4
3
of petroleum ether, frozen at ꢁ
materials; colorless microcrystals (from acetonitrile/
diethyl ether); yield 96 mg (39%).*IR (CH CN): 1890
/
196 8C, as starting
2
. Experimental
/
3
ꢁ
1
1
31
1
cm
NMR spectra identical with that of 1.*
C, 29.46; H, 6.14. Calc. for C H CoIrO P (683.55): C,
(CO):*/The cation exhibited H and P{ H}
/Anal. Found:
2
.1. General remarks
1
7
40
4 4
29.87; H, 5.90%.
All manipulations were performed under nitrogen
using standard Schlenk techniques. Solvents were dis-
tilled from the appropriate drying agents prior to use.*
NMR: JEOL FT-JNM-GX 270 and JEOL FT-JNM-
2.2.3. [Ir(PMe ) (H)(CH )][CpMo(CO) ] (3)
3
A solution of 115 mg (0.47 mmol) of [CpMo(CO) H]
3
4
3
3
/
in 30 ml of petroleum ether was added dropwise to a
vigorously stirred solution of 245 mg (0.48 mmol) of
[Ir(PMe ) CH ] in 20 ml of the same solvent. The
1
31
EX 270 (269.9 MHz for H and 109.4 MHz for P) at
092 8C; spectra referenced versus SiMe as internal or
versus H PO
2
/
4
3 4
3
as external standard (downfield
IR: Mattson Polaris.
product, which separated from solution as a colorless
precipitate, was collected by filtration and re-dissolved
in 10 ml of acetonitrile. Addition of diethyl ether
3
4
positive).*
/
Published procedures were used for the synthesis of
the starting materials PMe3 [11], [Ir(PMe ) ]Cl [12],
followed by cooling to ꢁ
/
20 8C furnished the complex
IR
NMR
5.06 (s; C H ); NMR data of the cation
3 4
[
CH ] [15], Na[Mn(CO) ] [16], [Ph PNPPh ][Mn(CO) ]
Rh(PMe ) ]Cl [13], [Ir(PMe ) CH ] [14], [Rh(PMe ) -
as pale yellow needles; yield 115 mg (32%).*
/
3
4
3 4
3
3 3
ꢁ
1
1
/
(CH CN): 1775, 1899 cm
(CO).* H
3
5
3
3
5
3
[
17], [Ph PNPPh ][Co(CO) ] [18], [CpMo(CO) H] [19],
3
(CD CN): dꢀ
/
3
4
3
3
5
5
and K[CpM(CO) ] (Mꢀ
/
Fe, Ru) [20,21].
matched those of 1 and 2.*Anal. Found: C, 33.28; H,
/
2

L. Dahlenburg, R. Hache / Inorganica Chimica Acta 350 (2003) 77ꢃ
/85
79
6
.48. Calc. for C H IrMoO P (757.59): C, 33.29; H,
4
2.2.6. [(Me P) Rh(m-CO) Fe(PMe )Cp] (6)
3 2 2 3
2
1
45
3
5
.99%.
The preparation was carried out as described for 5
method II) by treating 450 mg (1.01 mmol) of
(
[
K[CpFe(CO) ] in THF for 5 min at ambient conditions.
Crystallization of the filtered and evaporated reaction
Rh(PMe ) ]Cl with 220 mg (1.02 mmol) of
3 4
2
.2.4. [Ir(PMe ) (H)(CH )][CpFe(CO) ] (4)
3
2
4
3
2
[
CpFe(CO) H] was generated by adding a 0.92 ml
2
mixture from n-hexane at ꢁ
bimetallic complex as blackꢃ
mg (70%).*IR (THF): 1673, 1712 cm
NMR (THF-d ): dꢀ
/
20 8C furnished the hetero-
aliquot of a stock solution made up of 1.0 ml of glacial
acetic acid and 0.2 ml of thiophenol in 29 ml of
petroleum ether to 115 mg (0.53 mmol) of
/
green columns; yield 380
ꢁ
1
1
/
(CO).*
/
H
2
/
1.06 (d, J(P,H)ꢀ7 Hz; 1
/
K[CpFe(CO) ] suspended in 20 ml of petroleum ether
2
8
2
P(CH ) ), 1.20 (d, J(P,H)ꢀ7 Hz; 2 P(CH ) ), 4.40 (s,
/
[
23]. The resulting mixture was filtered over Celite and
3 3
3 3
C H ).*
/Anal. Found: C, 37.48; H, 6.62. Calc. for
the filtrate was condensed onto a frozen solution of 245
mg (0.48 mmol) of [Ir(PMe ) CH ] in petroleum ether (5
5
5
C H FeO P Rh (508.09): C, 37.82; H, 6.35%.
16 32 2 3
3
4
3
ml), as described for 1. After warming to room
temperature (r.t.), the product precipitated from the
reaction mixture as an orange solid, which was collected
2
.2.7. [(Me P) Ir(m-CO) Fe(PMe )Cp] (7)
3 3 2 3
535 mg (1.00 mmol) of [Ir(PMe ) ]Cl and 235 mg
1.09 mmol) of K[CpFe(CO) ] were combined in THF
40 ml) for 30 min at r.t. The resulting dark green
3 4
(
(
by filtration and washed with petroleum ether (3ꢄ
/
5
2
ml); yield 200 mg (60%).*IR (CH CN): 1790, 1865
/
3
ꢁ
1
1
1
reaction mixture was evaporated to dryness and the
remaining solids were extracted into a total of 30 ml of
petroleum ether. Filtration of the combined extracts
over Celite followed by partial evaporation of the
filtrate and cooling to ꢁ
as shiny crystals which had a distinct blackꢃ
in reflected light and a red color in transmitted light.
(
CO) cm .* H NMR (CD CN): 4.46 (s; C H ); H
/
3 5 5
3
1
1
and P{ H} NMR spectra of the cation were as given
for 1.*Anal. Found: C, 35.01; H, 6.79. Calc. for
C H FeIrO P (689.54): C, 34.84; H, 6.58%.
/
2
0
45
2 4
/
20 8C gave 455 mg (67%) of 7
/green luster
2
.2.5. [(Me P) Rh(m-CO) Mn(CO) PMe ] (5)
3 3 2 3 3
ꢁ1
1
*
/
IR (THF): 1645, 1685 cm
2
(CO).*
/
H NMR
8 Hz; 1 P(CH ) ), 1.27
(C D ): dꢀ
/
1.00 (d, J(P,H)ꢀ
/
I) A filtered hydrocarbon solution of [Mn(CO) H],
5
6
6
3 3
2
31
(d, J(P,H)ꢀ7 Hz; 3 P(CH ) ), 4.37 (s, C H ).* P
/
/
resulting from the addition of 180 ml (2.05 mmol) of
3 3
5
5
NMR (C D ): dꢀ 63.5 (s; IrP), 44.8 (s, FeP).*
Found: C, 33.36; H, 6.22. Calc. for C H FeIrO P
2 4
/
ꢁ
/
/
Anal.
CF SO H, diluted with 15 ml of pentane, to a
suspension of 1.56
6
6
3
3
g (2.07 mmol) of
Ph PNPPh ][Mn(CO)] in 15 ml of petroleum ether
19 41
(673.45): C, 33.88; H, 6.14%.
[
[
[
3
3
5
22], was condensed onto 165 mg (0.48 mmol) of
Rh(PMe ) CH ] frozen in petroleum ether (15 ml)
2
.2.8. [(Me P) Ir(m-CO) Ru(PMe )Cp] (8)
3 3 2 3
3
3
3
The synthesis followed the procedure outlined before,
using 175 mg (0.33 mmol) of [Ir(PMe ) ]Cl and 85 mg
by cooling with liquid nitrogen. The mixture was
then slowly warmed to 25 8C, filtered over Celite,
and concentrated to a residual volume of 5 ml.
3 4
(0.33 mmol) of K[CpRu(CO) ] in 25 ml of THF; red
2
crystals (from pentane); yield 55 mg (23%).*IR (THF):
/
Standing at ꢁ
complex 5 as yellow rhombs containing n-hexane
of crystallization, 5×1/2C H ; yield 180 mg (58%).
II) An equimolar mixture of Na[Mn(CO) ] (220 mg,
/
20 8C induced the deposition of
ꢁ
1
1
/
1
651, 1688 cm (CO).*
H NMR (C D ): dꢀ
/
1.15 (d,
6
2
6
2
J(P,H)ꢀ
/
9 Hz; 1 P(CH ) ), 1.26 (d, J(P,H)ꢀ
P(CH ) ), 4.29 (s, C H ).*
/
7 Hz; 3
/
3 3
6
14
3
1
/
P NMR (C D ): dꢀ
/
3 3
5
5
6
6
5
ꢁ
/
67.6 (s; IrP), 21.4 (s, FeP).*/Anal. Found: C, 31.26;
1
.01 mmol) and [Rh(PMe ) ]Cl (450 mg, 1.01 mmol)
3 4
H, 5.95. Calc. for C H IrO P Ru (718.67): C, 31.75;
H, 5.75%.
in 50 ml of THF was stirred for 5 min at r.t.
Removal of the volatiles in vacuo left a semi-solid
residue, which was re-dissolved in 60 ml of petro-
leum ether. Filtration over Celite followed by
concentration of the filtrate to 10 ml and standing
19 41
2 4
2.3. X-ray structure determinations
Single crystals of the salt-like complex 3 (size 0.60ꢄ
.20ꢄ0.15 mm) were grown from acetonitrile; the
1/
0.25 mm), 6 (size 0.35ꢄ
0.30 mm), 7 (size 0.40ꢄ0.40ꢄ0.40 mm), and 8
(size 0.50ꢄ0.50ꢄ0.40 mm) were selected from samples
that had been recrystallized from petroleum ether.
Diffraction measurements were made at ꢁ7092 8C
(5×1/2C H , 6, 7) and at 2092 8C (3, 8) on Siemens
P4 (3, 7, 8) and Philips PW 1100 (5×1/2C H , 6)
/
at ꢁ
crystalline 5×
/
20 8C furnished 510 mg (78%) of yellow
1/2C H .
0
/
/
6
14
specimens used for the structure analyses of 5×
/
ꢁ
1
IR (THF): 1718, 1745, 1870, 1895, 1962 cm
1
2C H (size 0.35ꢄ0.35ꢄ
/
/
/
6
14
2
(
1
CO).*
/
H NMR (C D ): dꢀ
/
1.03 (d, J(P,H)ꢀ
/
5 Hz;
Hz; 3
28.1 (d,
0.30ꢄ
/
/
/
6
6
2
P(CH ) ),
1
1.07
(d,
J(P,H)ꢀ
/
9
/
/
3
3
3
1
P(CH ) ).*
/
P{ H} NMR (C D ): dꢀ
/
ꢁ
/
3
3
6
6
1
J(Rh,P)ꢀ
/
147 Hz; RhP); 14.3 (br s; MnP).*
/Anal.
/
/
Found: C, 37.51; H, 6.89. Calc. for C H MnO P Rh×
/
/
/
1
7
36
5
4
6
14
1
/2C H (645.27): C, 37.23; H, 6.72%.
/
6
14
6
14

80
L. Dahlenburg, R. Hache / Inorganica Chimica Acta 350 (2003) 77ꢃ85
/
3
˚
diffractometers using graphite-monochromated Mo Ka
bꢀ
/
109.97(2)8, Vꢀ
/
2161.8(7) A , Zꢀ
/
4, dcalc
1.661 mm ; 3.0885U 5
155h 514, 05k 512, 05
collected, 3392 unique (Rint 0.0726); wRꢀ0.0510 for
all data and 217 parameters, Rꢀ0.0260 for 2681
intensities I ꢀ2s(I), GooFꢀ0.953. 7:
C H FeIrO P (673.45); monoclinic, P2 /n, aꢀ
ꢀ
/
1.561 g
24.068,
l 517)
ꢁ
3
ꢁ1
˚
0.71073 A): orientation matrix and unit
radiation (lꢀ
/
cm , m(Mo Ka)ꢀ
3882 reflections (ꢁ
/
/
/
cell parameters from the setting angles of at least 20
machine-centered medium-angle reflections; collection
/
/
/
/
/
/
/
ꢀ
/
/
of the diffraction intensities by v ꢃ
corrected for absorption by c scans [24]; 3: Tmin
.2450, Tmax 1/2C H : Tmin 0.6786,
0.4656; 5×
0.7533; 6: Tmin 0.5940, Tmax 0.6356; 7:
0.0736, Tmax 0.0966; 8: Tmin 0.0412, Tmax
/2u scans; data
/
ꢀ
/
/
/
ꢁ
/
0
ꢀ
/
/
ꢀ
/
/
6
14
19 41
2
4
1
˚
Tmax
Tmin
ꢀ
/
ꢀ
/
ꢀ
/
9.237(2), bꢀ
/
17.926(3), cꢀ
/
15.960(3) A, bꢀ93.05(2)8,
/
3
ꢁ3
˚
ꢀ
/
ꢀ
/
ꢀ
/
ꢀ
/
Vꢀ
Ka)ꢀ
(ꢁ115
unique (Rint
parameters, Rꢀ
GooFꢀ0.818.*8: C H IrO P Ru (718.67); monocli-
nic, P2 /n, aꢀ9.383(4), bꢀ
/
2639.0(9) A , Zꢀ
5.842 mm ; 1.715
/
4, dcalc
U 5
22, ꢁ205
0.0339); wRꢀ0.0525 for all data and 256
0.0237 for 4240 intensities I ꢀ2s(I),
ꢀ
/
1.695 g cm , m(Mo
27.068, 7739 reflections
l 520) collected, 5771
ꢁ
1
0
and subsequently refined by full-matrix least-squares
.1031. The structures were solved by direct methods
/
/
/
/
/
h 53, 05k 5
/
/
/
/
/
/
2
procedures on F with allowance for anisotropic thermal
ꢀ
/
/
motion of all non-hydrogen atoms employing the
WINGX package [25] and the relevant programs (SIR-97
/
/
/
/
1
9
41
2 4
˚
[
26], SHELXL-97 [27], ORTEP-3 [28], PARST-95 [29])
/
/
18.127(10), cꢀ
/
16.044(6) A,
4, dcalc 1.752 g
5.679 mm ; 1.705U 527.068,
125h 512, ꢁ235k 50, ꢁ205
7) collected, 5984 unique (Rint 0.0551); wRꢀ
0.0801 for all data and 256 parameters, Rꢀ0.0332 for
4688 intensities I ꢀ2s(I), GooFꢀ0.924.
1
3
˚
implemented therein. Carbon-bound hydrogen atoms
were included in the final structural models assuming
ideal geometry and using appropriate riding models.
The position of the hydride ligand in structure 3 was
inferred by means of the potential energy minimization
bꢀ
/
93.01(4)8, Vꢀ
/
2725(2) A , Zꢀ
/
ꢀ
/
ꢁ
3
ꢁ1
cm , m(Mo Ka)ꢀ
9159 reflections (ꢁ
l 5
/
/
/
/
/
/
/
/
/
/
/
/
ꢀ
/
/
/
procedure of XHYDEX [30]. During subsequent refine-
˚
H distance was fixed at 1.6 A in order to
/
/
ment, the Irꢀ
/
maintain a reasonable coordination geometry. The
C H ligand of complex 3 displayed twofold rotational
5
5
3. Results
disorder about the normal to the ring plane, which was
accounted for by assigning the respective carbon atoms
split occupancies of 0.5 each and treating the disordered
rings as idealized pentagons of variable metrics [27].
The methyliridium(I) complex [Ir(PMe ) CH ] [14]
3
3
4
underwent
clean
transformation
Mn, nꢀ
4: 2) and [Ir(PMe ) (H)(CH )][CpM(CO) ] (Mꢀ
into
5: 1; Mꢀ
[Ir(P-
Me ) (H)(CH )][M(CO) ] (Mꢀ
/
/
/Co,
3
4
3
n
According to the U s of several of the PMe carbon
?
ij 3
nꢀ
Mo, nꢀ
combined with the corresponding carbonyl hydrides
/
/
3
4
3
n
atoms, rotational disorder about the Irꢀ/P bonds of
/
3: 3; Mꢀ
/
Fe, nꢀ2: 4), respectively, when
/
structure 3 was suggested for these ligands, too, but was
ignored during refinement. The C atoms of the tri-
methylphosphine group attached to rhodium via phos-
[
(
M(CO) H] or [CpM(CO) H] in 1:1 stoichiometry
n n
Scheme 1). To facilitate isolation of the products, the
reactions were conducted in hydrocarbon solution, from
which the salt-like complexes precipitated as analytically
phorus atom P4 in structure 5×/1/2C H were similarly
6 14
found to be rotationally disordered over two sites, and
in this case the disorder was resolved with occupancies
of 0.55 and 0.45 for the particular carbon positions. The
n-hexane of solvation was located on Wyckoff position
pure samples. The NMR data of 1ꢃ4 (see Section 2)
/
were consistent with the cis hydridomethyl structure of
ꢂ
the [Ir(PMe ) (H)(CH )] cation shown in Scheme 1
3
4
3
2
b of the monoclinic P2 /n cell.*3: C H IrMoO P
/
1
21 45 3 4
and, in fact, corresponded in all respects with those
(
757.59); orthorhombic, P2 2 2 , aꢀ
/
9.729(2), bꢀ
/
1
1 1
3
˚
˚
1
5.387(4), cꢀ
1.682
U 527.078, 4698 reflections (ꢁ
19, 05l 525) collected (including 797 Friedel
pairs), 4503 unique (Rint 0.0344); wRꢀ0.1324 for all
data and 317 parameters, Rꢀ0.0542 for 2008 intensities
I ꢀ2s(I), GooFꢀ0.865.*5×1/2C H : C H MnO -
P Rh×1/2C H
/
19.979(4) A, Vꢀ
/
2991(1) A , Zꢀ
/
4,
;
ꢁ
3
ꢁ1
dcalc
.045
k 5
ꢀ
/
g
cm
,
m(Mo Ka)ꢀ
/5.096 mm
2
/
/
/
125
/
h 58, 05
/
/
/
/
/
ꢀ
/
/
/
/
/
/
/
6
14
17 36
5
/
(645.27); monoclinic, P2 /n, aꢀ
/
4
6
14
1
˚
1
8.046(2), bꢀ
/
9.544(1), cꢀ
/
19.474(4) A, bꢀ
/
115.77(3)8,
3
ꢁ3
˚
Vꢀ
Ka)ꢀ
205
unique (Rint
parameters, Rꢀ
GooFꢀ0.921.*6: C H FeO P Rh (508.09); monocli-
nic, P2 /n, aꢀ13.123(2), bꢀ
/
3020.5(8) A , Zꢀ
/
4, dcalc
1.201 mm ; 3.295U 5
h 518, 05k 510, 05
0.0631); wRꢀ0.0934 for all data and 318
0.0432 for 2611 intensities I ꢀ2s(I),
ꢀ
/
1.419 g cm , m(Mo
ꢁ
1
/
/
/
24.048, 5508 reflections
l 522) collected, 4750
(
ꢁ
/
/
/
/
/
/
/
ꢀ
/
/
/
/
/
/
1
6
32
2
3
Scheme 1. Oxidative addition of transition metal Mꢀ
/H acids to
˚
/
/
11.229(1), cꢀ
/
15.609(3) A,
[Ir(PMe CH ].
4
3
)
3
1

L. Dahlenburg, R. Hache / Inorganica Chimica Acta 350 (2003) 77ꢃ
/85
81
previously described by Thorn for the complex salts
ꢁ
38]. The [CpMo(CO)3]ꢁ counterion adopts piano stool
geometry, as expected [39].
ꢁ
ꢁ
[
isolated from oxidative addition of either HBF4 or
Ir(PMe ) (H)(CH )]X (X ꢀBF4 , PF6 ), which were
/
3
4
3
In the reactions leading to compounds 1ꢃ
base [Ir(PMe) CH ] interacts with the transition metal
MꢀH acids [M(CO)
way as with strong mineralic acids such as HBF
HPF [14] to yield [Ir(PMe (H)(CH
)]ꢂ as its con-
/4, the metal
HPF to [Ir(PMe ) CH ] in pyridine or diethyl ether
6
4
3
3 4
3
1
[
14].
The formulation of 1ꢃ
further confirmed by their conductance values in
/
n
H] and [CpM(CO)
n
H] in the same
or
/
4 as ionic complexes was
4
)
4
6
3
3
2
ꢁ1
ꢁ1
CH CN (Lꢀ for 3 and 4,
respectively) as well as by an X-ray structure determina-
/
87 and 83 cm ×
/
V
×
/
mol
jugate acid in a transformation that may be considered
to involve oxidative addition of a proton to iridium(I).
The clean formation of the products isolated from these
oxidative addition reactions mirrors the remarkable
stability of cis-alkyl(hydrido)iridium(III) species show-
ing no tendency to release alkane by reductive elimina-
tion as has been noticed for a number of related
examples described before [14,32,40].
3
tion of 3. The orthorhombic unit cell of space group
ꢂ
P2 2 2 contains four [Ir(PMe ) (H)(CH )] cations
3
1
1 1
3 4
ꢁ
accompanied by four well-separated [CpMo(CO)3]
anions. As evidenced from the interligand bond angles
Fig. 1), the octahedral coordination geometry about
(
iridium is considerably distorted by the steric demand of
the four PMe groups and the small size of the hydride
A different situation is encountered if the methylrho-
dium(I) complex [Rh(PMe ) CH ] [15] is chosen as a
substrate. This complex interacts with [Mn(CO) H] in
3
˚
2.354(4) A, reveal
no significant dependence on the nature of the trans
ligand. The Irꢀ
/
P distances, 2.341(4)ꢃ
/
3 3
3
5
˚
ligand and fall within the range from 2.31 to 2.38 A
III
petroleum ether by liberation of methane and concomi-
tant formation of a Rhꢀ
trimethylphosphine is partially transferred from rho-
dium to manganese, producing [(Me P) Rh(m-
/Mn bond. In addition,
typically spanned by Ir
3
ꢀ
/
PMe bonds opposite to Irꢀ
/
3
H, Irꢀ
/
sp -C, or Irꢀ
/
P in cis-octahedral [Ir(PMe ) -
3 4
ꢂ
(
H)(X)] cations (Xꢀ
/
CH OH, OH, OCH , SH) [31ꢃ
/
3
3
2
3
CO) Mn(CO) PMe ] (5), accompanied by unidentified
2
3
3
3
3]. Large thermal motion of the carbon atoms (see
CH3
bond to an uncorrected value of 2.04(2) A. Corrected for
riding motion [34], the IrꢀC bond length was calculated
by-products. In a more straightforward fashion, hetero-
binuclear complex 5 is obtained by a salt elimination
reaction occurring between [Rh(PMe ) ]Cl [13] and
Section 2) caused unrealistic shortening of the Irꢀ
/
˚
3
4
/
˚
˚
Na[Mn(CO) ] (Scheme 2).
5
[
29] as 2.11(2) A, close to the 2.123(6)ꢃ
/
2.192(7) A
3
sp -C) in other six-coordinate
The molecular structure of the 34 VE complex 5 (Fig.
) reveals two coordinatively saturated metal centers
observed for d(Irꢀ
PMe -substituted alkyl iridium(III) complexes [32,35ꢃ
/
2
/
3
linked by a doubly carbonyl-bridged metalꢀ
/
metal bond.
The four-membered RhC Mn metallaheterocycle is
2
folded along the Rhꢀ/Mn vector, the dihedral angle
between the two Rh(m-CO)Mn planes being 122.4(3)8.
The coordination geometries about manganese and
rhodium are approximately octahedral (Mn) and close
to square-pyramidal (Rh), if metalꢀ
ignored. Due to the strong trans influence of carbonyl
ligands, the RhꢀPMe bonds facing the CO bridges in
the basal plane of the pyramid are considerably elon-
/metal bonding is
/
3
Fig. 1. Molecular structure of 3 showing the twofold disorder of the
C
5
H
5
ring (H atoms of Cp and PMe
3
ligands omitted). Selected
interatomic distances (A) and angles (8) for cation: IrꢀP1, 2.347(4); Irꢀ
P2, 2.341(4); IrꢀP3, 2.342(4); IrꢀP4, 2.354(4); IrꢀC21, 2.04(2); IrꢀH,
.6 (H position calculated and fixed [30]). P1ꢀIrꢀP2, 161.35(15); P1ꢀ
IrꢀP3, 95.59(14); P1ꢀIrꢀP4, 96.60(15); P2ꢀIrꢀP3, 94.01(15); P2ꢀIrꢀ
P4, 97.68(15); P3ꢀIrꢀP4, 97.95(16); P1ꢀIrꢀC21, 87.1(7); P2ꢀIrꢀC21,
0.7(6); P3ꢀIrꢀC21, 169.6(7); P4ꢀIrꢀC21, 91.6(7); P1ꢀIrꢀH1, 83(2);
P2ꢀIrꢀH1, 82(1); P3ꢀIrꢀH1, 85(2); P4ꢀIrꢀH1, 177(2); C21ꢀIrꢀH1,
5(2). Anion: MoꢀC1, 1.95(2), MoꢀC2, 1.89(2); MoꢀC3, 1.88(2); C1ꢀ
O1, 1.19(2), C2ꢀO2, 1.22(2), C3ꢀO3, 1.20(2); Moꢀ ꢀ ꢀcentroid(C4ꢀC8),
.11(2); Moꢀ ꢀ ꢀcentroid(C4aꢀC8a), 2.08(2). C1ꢀMoꢀC2, 87.6(7); C1ꢀ
MoꢀC3, 85.1(7); C2ꢀMoꢀC3, 91.0(6); MoꢀC1ꢀO1, 175.8(14); Mnꢀ
C2ꢀO2, 177.2(13); MnꢀC3ꢀO3, 173.9(15).
˚
/
/
/
/
/
/
1
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
8
/
/
/
/
/
/
/
/
/
/
/
/
/
/
8
/
/
/
/
Scheme 2. Formation of [(Me
3
P)
3
2 3 3
Rh(m-CO) Mn(CO) PMe ].
/
/
/
2
/
/
/
/
1
/
/
/
/
/
/
pK
[Mn(CO)
a
(MeCN, 25 8C)ꢀ
/
19.4, 15.1, 13.9, and 8.4 for [CpFe(CO)
2
H],
/
/
/
5
H], [CpMo(CO)
3
H], and [Co(CO) H], respectively [3].
4

82
L. Dahlenburg, R. Hache / Inorganica Chimica Acta 350 (2003) 77ꢃ85
/
ꢂ
When the [Rh(PMe ) ] cation was combined with
3
4
ꢁ
[
CpFe(CO)2] in place of [Mn(CO)5]ꢁ as a substituting
nucleophile, heterobimetallic [(Me P) Rh(m-CO) Fe(P-
3
2
2
Me )Cp] (6) was produced as a result of metalꢀ
/
metal
bond formation, phosphine loss and partial transfer of
3
PMe from rhodium to iron (Scheme 3). A perspective
3
view of the molecule is given in Fig. 3. The Rh(m-
CO) Fe core possesses a butterfly conformation with a
2
Rh(m-CO)Fe interplanar dihedral angle of 157.3(2)8.
Although most of the differences in the Mꢀ
/
m-CO
C2, 2.014(3); Feꢀ
C2, 1.925(3) A) can savely be allotted
separations (Rhꢀ
/
C1, 1.996(3); Rhꢀ
/
/
˚
C1, 1.869(3); Feꢀ
/
to the smaller size of the iron atom, there appears to be
some asymmetry in the carbonyl bridges to such an
extent that the CO ligand bonded through C1 interacts
stronger with Fe than with Rh, while the opposite is true
for the carbonyl group linked to the two metals via C2.
Fig. 2. Molecular structure of 5 showing the rotational disorder of one
rhodium-bonded PMe ligand (H atoms omitted). Selected bond
lengths (A) and angles (8): RhꢀMn, 2.6695(14); RhꢀP2, 2.415(2);
RhꢀP3, 2.324(2); RhꢀP4, 2.413(2); RhꢀC1, 1.984(6); RhꢀC2,
.011(8); MnꢀP1, 2.312(2); MnꢀC1, 2.045(6); MnꢀC2, 2.076(8);
MnꢀC3; 1.798(8); MnꢀC4, 1.790(8); MnꢀC5, 1.796(8); C1ꢀO1,
.204(6); C2ꢀO2, 1.190(8); C3ꢀO3, 1.172(8); C4ꢀ
O5, 1.163(8). P2ꢀRhꢀP3, 97.54(7); P2ꢀRhꢀP4, 99.91(7); P3ꢀ
RhꢀC1, 86.0(2); P2ꢀRhꢀC2, 162.7(2); P3ꢀRhꢀ
RhꢀC2, 98.1(2); P4ꢀRhꢀC1, 157.6(2); P4ꢀRhꢀ
MnꢀC1, 82.9(2); P1ꢀMnꢀC2, 83.1(2); P1ꢀMnꢀ
78.8(2); P1ꢀMnꢀC4, 89.2(2); P1ꢀMnꢀC5, 91.2(2); C1ꢀMnꢀ
1.0(3); C1ꢀMnꢀC3, 97.7(3); C1ꢀMnꢀC4, 90.4(3); C1ꢀMnꢀ
68.1(3); C2ꢀMnꢀC3, 98.2(3); C2ꢀMnꢀC4, 169.1(3); C2ꢀMnꢀ
8.1(3); C3ꢀMnꢀC4, 89.6(3); C3ꢀMnꢀC5, 88.5(3); C4ꢀMnꢀ
9.8(3); RhꢀC1ꢀMn, 83.0(2); RhꢀC2ꢀMn, 81.5(3); RhꢀC1ꢀ
38.7(5); RhꢀC2ꢀO2, 139.6(5); MnꢀC1ꢀO1, 138.3(4); MnꢀC2ꢀ
38.8(5); MnꢀC3ꢀO3, 170.6(6); MnꢀC4ꢀO4, 179.3(7); MnꢀC5ꢀ
77.1(6).
3
This finding arises from the larger Feꢀ
142.1(2)8, compared with the value of 134.9(2)8 mea-
sured for RhꢀC1ꢀO1 and, by similar reasoning, from
the smaller angle FeꢀC2ꢀO2, 135.5(2)8, set against the
RhꢀC2ꢀO2 angle of 141.9(2)8. In full agreement with
this view, the Rhꢀ
slightly longer than the Rhꢀ
/
C1ꢀ
/
O1 angle,
˚
/
/
/
/
/
/
2
/
/
/
/
/
/
/
/
/
/
/
1
/
/
/
O4, 1.160(7); C5ꢀ
/
/
/
/
/
/
/
/
Rhꢀ
/
P4,
˚
/
P1 bond trans to C2, 2.3160(9) A, is
P2 linkage opposite C1
2.3023(10) A). The complex may therefore be looked
upon as a [15ꢂ17]-electron compound composed of a 15
VE {Rh(PMe ) CO} fragment and a 17 VE {CpFe(P-
1
9
8
1
8
1
8
9
1
1
1
01.15(6); P2ꢀ
9.5(2); P3ꢀ
4.3(2); P1ꢀ
/
/
/
/
/
/
C1,
C2,
C3,
C2,
C5,
C5,
C5,
/
/
/
/
/
/
/
/
/
/
/
/
/
˚
(
/
/
/
/
/
/
/
/
/
/
/
/
/
3
2
/
/
/
/
/
/
/
/
/
/
/
/
Me )CO} moiety, both tied together by a Rhꢀ
3
/
Fe single
/
/
/
/
/
/
O1,
O2,
O5,
bond. Within the P RhC framework, the four-coordi-
2
2
/
/
/
/
/
/
nate surroundings of the formal 16-electron metal center
RhꢀFe bonding neglected) deviates considerably from
planarity, as evidenced from the angle between the
normals to the two planes defined by the P1ꢀRhꢀP2
/
/
/
/
/
/
(
/
˚
gated (2.413(2) and 2.415(2) A) in comparison with the
/
/
distance between rhodium and the apically coordinated
˚
Mn
phosphine (2.324(2) A). The length of the Rhꢀ
/
˚
linkage, 2.669(1) A, is almost identical with that
measured for
[Cp(i-Pr P)Rh(m-CO)(m-Cꢁ
/
3
˚
CH )Mn(CO)Cp] (2.667(1) A) [41]. In contrast to the
2
latter complex and also at variance with
[
(C Me )Rh(CO)(m-CO) Mn(CO)Cp] [42], featuring dis-
/
5
5
2
tinctly unsymmetric Rh(m-CX) Mn frameworks (Xꢀ
O,
CH ) as a consequence of the different 18/16 valence
2
2
electron configurations of the two metal atoms, the
bridging carbonyl ligands of 5 are arranged in an
essentially symmetric fashion. Thus, the angles Rhꢀ
/
Cꢀ
139.6(5) A, are identical
within experimental error, and the values obtained for
/
˚
O and Mnꢀ
/
Cꢀ
/
O, 138.3(4)ꢃ
/
˚
d(Mnꢀm-CO), 2.045(6) and 2.076(8) A, differ only
/
slightly from the corresponding distances between the
˚
m-CO groups and rhodium, 1.984(6) and 2.011(8) A. We,
therefore, regard [(Me P) Rh(m-CO) Mn(CO) PMe ] as
3
3
2
3
3
a covalently bonded heterometallic complex with a [17ꢂ
/
1
7]-electron configuration rather than an [18ꢂ
/
16]-
electron species with the metals linked by 180
/
16 VE
]ꢂ and [Ir(PMe ]ꢂ cations with
3 4 3 4
Scheme 3. Reactions of [Rh(PMe ) )
ꢁ
donor bonds of order one [41,42].
[CpM(CO)
2
]
(MꢀFe, Ru).
/

L. Dahlenburg, R. Hache / Inorganica Chimica Acta 350 (2003) 77ꢃ
/85
83
membered IrC M rings which adopt distinctly folded
2
conformations (dihedral angle between the two Ir(m-
CO)M planes, 133.0(2)8 in 7 and 127.7(2)8 in 8,
respectively). As evidenced from the metalꢀm-CO dis-
/
tances and angles given in the legends to Figs. 4 and 5,
the CO bridges show an only small degree of asymme-
try, being slightly bent toward the iron and, respectively,
ruthenium center. Disregarding the bond to Fe or Ru,
the coordination geometry about iridium can be ap-
proximated by a distorted square pyramid with the
phosphorus atoms P1 and P3 and the carbon atoms of
the CO bridges in basal positions. In line with the
bonding pattern displayed by [(Me P) Rh(m-CO) -
3
3
2
Mn(CO) PMe ] (vide supra), the lengths of the Irꢀ
/
3
3
PMe linkages opposite the trans bond-weakening
carbonyl ligands are considerably longer than the
bond between iridium and the phosphine located in
3
˚
Fig. 3. Molecular structure of 6. Selected interatomic distances (A)
and angles (8): RhꢀFe, 2.5748(6); RhꢀP1, 2.3160(9); RhꢀP2,
.3023(10); RhꢀC1, 1.996(3); RhꢀC2, 2.014(3); FeꢀP3, 2.1695(11);
FeꢀC1, 1.869(3); FeꢀC2, 1.925(3); Feꢀ ꢀ ꢀcentroid(C3ꢀC7), 1.736(4).
P1ꢀRhꢀP2, 98.68(3); P1ꢀRhꢀC1, 86.16(9); P1ꢀRhꢀC2, 160.84(11);
P2ꢀRhꢀC1, 151.47(11); P2ꢀRhꢀC2, 92.45(10); P3ꢀFeꢀC1, 89.09(11);
P3ꢀFeꢀC2, 88.52(11); P3ꢀFeꢀ ꢀ ꢀcentroid(C3ꢀC7), 125.2(2); C1ꢀFeꢀ
C2, 98.42(13); Feꢀ ꢀ ꢀcentroid(C3ꢀC7), 123.4(2); C2ꢀ
C1ꢀ
C7), 122.7(2); RhꢀC1ꢀFe, 82.97(12); RhꢀC2ꢀFe,
C1ꢀO1, 134.9(2); RhꢀC2ꢀO2, 141.9(2); FeꢀC1ꢀO1,
C2ꢀO2, 135.5(2).
/
/
/
the apex of the pyramid: d(Irꢀ
/
P1) and d(Irꢀ
/
P3),
˚
P2), 2.270(2) A for both
2
/
/
/
˚
2
.345(1)ꢃ
/
2.351(2) A; d(Irꢀ
/
/
/
/
/
/
/
/
/
/
compounds. The Irꢀ
/
Fe separation found for 7,
/
/
/
/
/
/
˚
2.6470(7) A, matches the range from 2.5672(9) to
/
/
/
/
/
/
˚
2.7178(9) A reported for several other carbonyl-bridged
/
/
/
dinuclear IrFe complexes [48ꢃ
molecule 8, 2.735(1) A, is much shorter than the
/
50]. The Irꢀ
/
Ru bond in
Feꢀ ꢀ ꢀcentroid(C3ꢀ
/
/
/
/
/
˚
8
2.06(13); Rhꢀ
/
/
/
/
/
/
˚
2.8892(9) A recently reported [51] for
142.1(2); Feꢀ
/
/
2.8091(3)ꢃ
/
[
IrH(CO)(m-Ph PCH PPh ) (m-CO)Ru(CO) ] and two
2
2
2 2
2
related cations, [Ir(CO)(m-Ph PCH PPh ) (m-CO)(m-
2
2
2 2
and C1ꢀ
/
Rhꢀ
/
C2 fragments, 32.6(2)8, which is much
ꢂ
CH )Ru(CO) ] and [Me PIr(CO)(m-Ph PCH PPh ) -
2
2
3
2
2
2 2
larger than the limiting value of 08 for planar coordina-
ꢂ
(
m-CH )Ru(CO) ] , but compares reasonably well with
2
2
˚
Fe distance, 2.5748(6) A,
tion. A comparison of the Rhꢀ
/
with previous data is difficult, since there are only few
structurally characterized RhFe heterobimetallics con-
taining carbonyl-bridged but otherwise unsupported
Rhꢀ
length determined for 5 is much shorter than the Rhꢀ
separations in [(Ph PC H PPh )Rh(m-C H )(m-CO)Fe-
/
Fe linkages. In any case, the metalꢀ
/
metal bond
/Fe
2
2
4
2
7
7
˚
CO) ] (2.762(2) A [43]) and also significantly shorter
2
(
t
than the bonds found in [(Me P) Rh(m-PBu )(m-
3
2
2
˚
CO)Fe(CO) PMe ] (2.665(1) A [44]), [(Ph P)Rh(CO){m-
2
3
3
˚
A
P(C H -cyclo) }(m-CO)Fe(CO) (PPh ) ] (2.660(1)
6
11
2
2
3 2
[
45]), or [(RC H )Fe(m-Ph PCH PPh )(m-CO) RhX ]
5
4
2
2
2
2
2
˚
Fe), 2.612 A
(
[
Rꢀ
/
H, CH ; Xꢀ
/
Cl, I; average d(Rhꢀ
/
3
46,47]), even though in the latter cases metalꢀ
/metal
bonding is supported by bridging mono- or bidentate
phosphorus ligands in addition to CO.
In compound 6 the iron atom achieves a formal 18-
electron state, while rhodium rests in a coordinatively
unsaturated 16-electron environment. The coordina-
˚
Fig. 4. Molecular structure of 7. Selected interatomic distances (A)
and angles (8): IrꢀFe, 2.6470(7); IrꢀP1, 2.3445(12); IrꢀP2, 2.2699(12);
IrꢀP3, 2.3462(12); IrꢀC1, 2.037(4); IrꢀC2, 2.044(4); FeꢀP4,
.1651(16); FeꢀC1, 1.921(4); FeꢀC2, 1.927(4); Feꢀ ꢀ ꢀcentroid(C3ꢀ
C7), 1.745(5). P1ꢀIrꢀP2, 98.72(4); P1ꢀIrꢀP3, 94.89(4); P2ꢀIrꢀP3,
101.89(4); P1ꢀIrꢀC1, 160.80(12); P1ꢀIrꢀC2, 84.12(12); P2ꢀIrꢀ
Irꢀ Irꢀ Irꢀ
49.71(13); P4ꢀ C1, 85.76(14); P4ꢀ
/
/
/
/
/
/
/
tively saturated [17ꢂ17]-electron analogs of RhMn
/
2
/
/
/
complex 5 with both the Group 9 and the Group 8
/
/
/
/
/
/
metal in the 18-electron state, [(Me P) Ir(m-CO) M(P-
/
/
/
/
/
/
C1,
3
3
2
9
1
8.80(13); P2ꢀ
/
/
C2, 108.19(13); P3ꢀ
/
/
C1, 89.13(12); P3ꢀ
/
/
C2,
Me )Cp], where Mꢀ
/
Fe (7) or Ru (8), were isolated if
Ir(PMe ) ]Cl [12] and the respective carbonyl metalate
3
/
Feꢀ
/
/
Feꢀ
/
C2, 83.57(14); P4ꢀ
/
[
3
4
Feꢀ ꢀ ꢀcentroid(C3ꢀ
Feꢀ ꢀ ꢀcentroid(C3ꢀ
IrꢀC1ꢀFe, 83.9(2); Irꢀ
O2, 139.3(3); FeꢀC1ꢀO1, 135.9(3); Feꢀ
/
C7),
122.1(2);
C1ꢀ
/
Feꢀ
/
C2,
89.3(2);
C7), 131.9(2);
O1, 140.1(3); IrꢀC2ꢀ
O2, 136.7(3).
C1ꢀ
/
were allowed to interact in 1:1 stoichiometry in THF.
The basic structural feature of the two isostructural
/
C7), 128.7(2); C2ꢀ
C2ꢀFe, 83.5(2); Irꢀ
C2ꢀ
/
Feꢀ ꢀ ꢀcentroid(C3ꢀ
/
/
/
/
/
/
C1ꢀ
/
/
/
complexes is a central Ir(m-CO) M core with four-
/
/
/
/
2

84
L. Dahlenburg, R. Hache / Inorganica Chimica Acta 350 (2003) 77ꢃ85
/
bination with [Mn(CO) H] but rather affords
5
[
(Me P) Rh(m-CO) Mn(CO) PMe ] as a result of meth-
/
3
3
2
3
3
ane ejection accompanied by metalꢀ
tion. An important difference between the observed
[
[
metal bond forma-
ꢂ
Ir(PMe ) (H)(CH )]
cation and the presumed
Rh(PMe ) (H)(CH )] complex is that the former is
3
4
3
ꢂ
3
3
3
saturated (18 VE) while the latter is unsaturated (16
VE). Reductive elimination frequently requires initial
dissociation of a s-donor ligand. Hence, the proclivity
of the alkyl(hydrido)rhodium(III) complex to release
methane most probably originates from its coordinative
unsaturation, which is expected to increase the rate of
elimination [53]. A more direct route to [(Me P) Rh(m-
3
3
CO) Mn(CO) PMe ] involves the salt elimination reac-
2
3
3
tion of [Rh(PMe ) ]Cl with Na[Mn(CO) ]. Formation of
3
4
5
doubly carbonyl-bridged metalꢀ
/
metal bonds and partial
transfer of trimethylphosphine from rhodium or iridium
to the heterometal giving [(Me P) M(m-CO) M?(P-
3
n
2
˚
Fig. 5. Molecular structure of 8. Selected interatomic distances (A)
and angles (8): IrꢀRu, 2.7348(14); IrꢀP1, 2.347(2); IrꢀP2, 2.270(2); Irꢀ
P3, 2.351(2); IrꢀC1, 2.033(6); IrꢀC2, 2.037(6); RuꢀP4, 2.253(2); Ruꢀ
C1, 2.032(6); RuꢀC2, 2.049(6); Ruꢀ ꢀ ꢀcentroid(C3ꢀC7), 1.935(7). P1ꢀ
IrꢀP2, 99.72(6); P1ꢀIrꢀP3, 95.21(6); P2ꢀIrꢀP3, 102.87(7); P1ꢀIrꢀC1,
60.1(2); P1ꢀIrꢀC2, 84.0(2); P2ꢀIrꢀC1, 98.4(2); P2ꢀIrꢀC2, 104.5(2);
P3ꢀIrꢀC1, 88.8(2); P3ꢀIrꢀC2, 152.4(2); P4ꢀRuꢀC1, 83.8(2); P4ꢀRuꢀ
C2, 82.3(2); P4ꢀRuꢀ ꢀ ꢀcentroid(C3ꢀC7), 122.4(3); C1ꢀRuꢀC2, 83.2(2);
C1ꢀRuꢀ ꢀ ꢀcentroid(C3ꢀC7), 131.6(3); C2ꢀRuꢀ ꢀ ꢀcentroid(C3ꢀC7),
35.3(3); IrꢀC1ꢀRu, 84.6(2); IrꢀC2ꢀRu, 84.0(2); IrꢀC1ꢀ
40.2(4); IrꢀC2ꢀO2, 140.0(5); RuꢀC1ꢀO1, 135.1(4); RuꢀC2ꢀ
35.8(5).
(
PMe )Cp] with nꢀ
/
2 (Mꢀ
/
Rh; M?ꢀ
/
Fe) or 3 (MꢀIr;
/
3
/
/
/
/
M?ꢀ
substitution reactions carried out between tetrakis(tri-
methylphosphine)rhodium and iridium cations
and carbonyl(cyclopentadienyl)ferrate
/Fe, Ru) are also common features of several
/
/
/
/
/
/
/
/
/
/
/
/
/
/
ꢀ
/
1
/
/
/
/
/
/
ꢂ
[
M(PMe ) ]
3 4
/
/
/
/
/
/
/
/
ꢁ
and ꢀruthenate anions [CpM?(CO) ] .
/
2
/
/
/
/
/
/
/
/
1
1
1
/
/
/
/
/
/
O1,
/
/
/
/
/
/
O2,
5. Supplementary material
Crystallographic data (excluding structure factors) for
the structural analyses have been deposited at the
˚
distances of 2.6985(7) and 2.7727(9) A, previously found
for the Ir(m-CO)Ru building blocks of two tetranuclear
Cambridge Crystallographic Data Centre CCDC Nos.
1/2C H ), 183057 (6), 183058 (7),
6 14
IrRu clusters [52].
3
1
83055 (3), 183056 (5×
/
and 183059 (8). Copies of the data can be obtained free
of charge on application to The Director, CCDC, 12
4
. Discussion
Union Road, Cambridge CB2 1EZ, UK (fax: ꢂ
/
44-
1223-336-033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
This study has shown that [Ir(PMe ) CH ] as an
3
4
3
electron-rich methyliridium(I) compound interacts with
a number of transition metal hydrides in a similar way
as previously observed for [Ir{(t-BuP(CH CH -
Acknowledgements
2
2
CH PPh ) }Cl] [10], yielding ionic cis-alkyl(hydrido)ir-
2
2 2
ꢁ
idium(III) products, [Ir(PMe ) (H)(CH )]X (X ꢀ
/
Financial support from the Fonds der Chemischen
Industrie (Frankfurt/Main) is gratefully acknowledged.
We are also indebted to Degussa AG (Hanau) for
several generous gifts of rhodium and iridium salts.
Diffractions intensities were measured by Dr. F. Knoch
and Dr. G. Liehr of this institute.
3
4
3
ꢁ
5 4 3
ꢁ
ꢁ
[
Mn(CO) ] , [Co(CO) ] , [CpMo(CO) ] , [CpFe-
ꢁ
(
dium(I). In these reactions, the hydrido complexes
CO) ] ) by oxidative addition of a proton to iri-
2
behave as acids [2,3], similar to HCl or HBF , which
4
on combination with [Ir{t-BuP(CH CH CH PPh ) }Cl]
2
2
2
2 2
or [Ir(PMe ) CH ] afford [Ir{t-BuP(CH CH CH -
2
3
4
3
2
2
PPh ) }(H)(Cl)]Cl [10] and [Ir(PMe ) (H)(CH )]BF
4
2
2
3 4
3
[
product [Ir(PMe ) (H)(CH )] as a cis hydridomethyl
14], respectively. The existence of the oxidative addition
ꢂ
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3
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a comment of one of the referees, pointing out that it is quite
[
27] G.M. Sheldrick, SHELX-97*
/
Program for the Refinement of
Crystal Structures from Diffraction Data (release 97-2), Univer-
likely that reductive elimination is more favorable for
[Rh(PMe
of the coordinative unsaturation of the former.
3 3 3 3 4 3
) (H)(CH ) (H)(CH )] because
)]ꢂ than for [Ir(PMe
ꢂ
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