Synthesis and coordination behavior of planar-chiral ferrocene alkenylphosphines

Inorg. Chem. 2006, 45, 8785−8798

Synthesis and Coordination Behavior of Planar-Chiral Ferrocene

Alkenylphosphines

Petr Sˇteˇpnicˇka* and Ivana C´ısarˇova´

Department of Inorganic Chemistry, Faculty of Science, Charles UniVersity in Prague,

HlaVoVa 2030, 12840 Prague, Czech Republic

Received July 11, 2006

A series of planar-chiral ferrocene alkenylphosphines, (S_p)-2-(diphenylphosphino)-1-vinylferrocene (2), (S_p)-2-

(diphenylphosphino)-1-(prop-1-en-1-yl)ferrocene (3; as a mixture of Z and E isomers in ca. 5:1 ratio), and (E,S_p)-

2-(diphenylphosphino)-1-(2-phenylethen-1-yl)ferrocene ((E)-4), was obtained by Wittig and Horner

Emmons reactions from the common precursor, (S_p)-2-(diphenylphosphino)ferrocene-1-carboxaldehyde (1).

Coordination properties of these novel ferrocene donors were studied in their palladium(II) and tungsten(0) carbonyl

complexes. The reaction between 2 and [ Pd( 2- (dimethylamino)methyl- phenyl-

-Cl)(L^NC₂] (5, L^NCC¹)

gave the bridge-cleavage product [PdCl(L^NC)(2- P)] (6) while the reaction with [Pd(L^NC)(MeCN)₂]ClO₄(7) yielded

the cationic bis(chelate) [Pd(L^NC)(2- ²κP)]ClO₄(8). Chelate complexes of the type [W(CO)₄(L- ²κP)] (9 with L

2; (Z/E)-10 with L

(Z/E)-3) were obtained by reacting [W(CO)₄(cod)] (cod ) η^{2 2}-cycloocta-1,5-diene) with the

appropriate phosphinoalkene in refluxing toluene while a similar reaction with (E)-4 yielded mixtures of [W(CO)₅-

(4- P)] ((E)-11) and [W(CO)₄(4-

²κP)] ((E)-12). All compounds were characterized by spectral methods (multinuclear

−Wadsworth−

−

{

µ

)

}

)

{

κN}

κ

η

:

η

:

)

:η

κ

η :

NMR, IR, MS, and CD), and the structures of 1, 2, 8, 9, (Z/E)-10, and (E)-11 were corroborated by X-ray diffraction

analysis. Ligands 2 and (E)-4 as well as their complexes 6, 8, 9, (E)-11, and (E)-12 were further studied by

electrochemical methods.

Introduction

area remaining largely a virgin field, which markedly

contrasts with the number of functionalized vinylferrocenes

already known. For instance, racemic vinylferrocenes bearing

an additional functional group in position 2 of the ferrocene

unit (see Chart 1, structure A; Y ) Cl, C(O)Ph, C(OH)Ph₂,

C(O)NHPh) were prepared as early as 1971 by base-induced

elimination from the respective (2-ferrocenylethyl)ammo-

nium salts.²More recent examples include predominantly

synthetic intermediates occurring en route to other ferrocene

derivatives. Thus, (S_p)-2-formyl-1-vinylferrocene (A, Y )

CHO) and its related hydroxymethyl compounds [A, Y )

CH₂OH and CH₂OSiMe₂(t-Bu)] were synthesized and further

utilized in the synthesis of conjugated alkenes [A; Y )

(CHdCH)_n(C₆H₄NO₂-4), n ) 1-3] with an aim of preparing

new materials for nonlinear optics.³Pyridyl-substituted

vinylferrocenes (A, Y ) 2-chloropyrid-3-yl and 2-vinylpyrid-

3-yl) were used as precursors to ferroceno-fused (iso)-

quinolines,⁴while (S_p)-1-vinylferrocene-2-carboxylic acid (A,

Multidentate ferrocene phosphines proved successful as

both versatile ligands in the common laboratory praxis and

efficient catalyst components at industrial scale.¹Their

chemistry, however, is still strongly dominated by com-

pounds combining the “standard” donor groups, i.e., by

ligands of the PP, PN, and PO types; only little attention

has been paid to coordination chemistry and catalysis with

compounds bearing another soft donor group in addition to

the phosphine moiety.^1d

This is particularly the case of ferrocene ligands that

combine the usual donor groups with potentially π-donating

functionalities such as alkenyl groups that still represent an

* To whom correspondence should be addressed. E-mail: stepnic@

natur.cuni.cz.

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Catalysis in Metallocenes-Synthesis, ReactiVity, Applications; Togni,

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10.1021/ic061278g CCC: $33.50

Published on Web 08/30/2006

Inorganic Chemistry, Vol. 45, No. 21, 2006 8785

Sˇteˇpnicˇka and C´ısarˇova´

rocene (Chart 1, E)¹¹and the related alkynyl-phosphine

sulfide, 1′-(diphenylthiophosphoryl)-1-ethynylferrocene (Chart

1, F).¹²As a next step in exploring the chemistry of

ferrocene-based P/π-donors, we turnedsin view of the well-

established chemistry of ortho-alkenyl-substituted triphenyl-

phosphines¹³sto planar-chiral 2-(diphenylphosphino)-1-alk-

enylferrocenes. In this contribution we report about the

preparation of several enantiopure phosphinoferrocenes

substituted by various alkenyl groups and their coordination

behavior in palladium(II) and tungsten-carbonyl complexes.

We also describe the solid-state structures and electrochemi-

cal properties of the obtained compounds.

Chart 1

Y ) CO₂H) and its carbamate (A, Y ) NHC(O)OCH₂Ph)

represent the key intermediates in the synthesis of chiral

phosphinoamine and amidinato ligands.⁵Finally, N-substi-

tuted amides of (R_p)-1-vinylferrocene-2-carboxylic acid that

are accessible by sparteine-mediated diastereoselective ortho-

metalation of FcC(O)NEt(CMe₂Ph) followed by vinylation

of carboxaldehyde intermediates [A, Y ) C(O)NHR and

C(O)NR₂] were further converted to planar-chiral, phosphino-

substituted ferrocene lactones.⁶Yet another example in which

two potentially π-donating groups are combined is 2-ethinyl-

1-vinylferrocene (A, Y ) CtCH).⁷

Phosphorus-substituted vinylferrocenes, which were not

mentioned in the above list, were also synthesized either

unintentionally or served just as reaction intermediates. The

representative examples are (R_p)-2-(diphenylphosphino)-

1′,2′,3′,4′,5′-pentamethyl-1-vinylferrocene (Chart 1, B), which

was obtained from heating (S,R_p)-2-(diphenylphosphino)-

1′,2′,3′,4′,5′-pentamethyl-1-(1-(dimethylamino)ethyl)ferro-

cene with acetic anhydride,⁸and (R_p)-2-(diphenylphosphinoyl)-

1-vinylferrocene (Chart 1, C), which served as a precursor

to planar-only chiral (R_p)-1-diphenylphosphino-2-ethylfer-

rocene.⁹The related diphosphine, 2,1′-bis(diphenylphos-

phino)-1-vinylferrocene (Chart 1, D), is also known and was

employed in the preparation of polymer-supported palladium

catalyst.¹⁰However, there has been as yet no systematic

investigation into the donor properties of these potentially

interesting molecules.

Results and Discussion

Preparation and Structural Characterization of the

Ligands.¹⁴Vinyl phosphine 2¹⁵was synthesized by Wittig

vinylation from (S_p)-2-(diphenylphosphino)-1-ferrocenecar-

boxaldehyde¹⁶(1; Scheme 1). Purification by column chro-

matography followed by crystallization from heptane af-

forded the compound as an air-stable, rusty brown crystalline

solid in a very good yield.

(11) Sˇteˇpnicˇka, P.; C´ısaˇrova´, I. Collect. Czech. Chem. Commun. 2006, 71,

215-236.

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2871.

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A.; Johnson, R. N.; Tomkins, I. B. Inorg. Chem. 1974, 13, 346-350.

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M. L. J. Organomet. Chem. 1986, 314, 323-331. (j) Bennett, M. A.;

Chiraratvatana, C.; Robertson, G. B. Organometallics 1988, 7, 1394-

1402. (k) Bennett, M. A.; Chiraratvatana, C.; Robertson, G. B.;

Tooptakong, U. Organometallics 1988, 7, 1403-1409. (l) Cavell, K.

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Pritchard, R. G. J. Chem. Soc., Dalton Trans. 2000, 2287-2294. (2-

Ph₂PC₆H₄)CH₂CHdCH₂(II): (n) Interrante, L. V.; Bennett, M. A.;

Nyholm, R. S. Inorg. Chem. 1966, 5, 2212-2217. (o) Bennett, M.

A.; Kneen, W. R.; Nyholm, R. S. Inorg. Chem. 1968, 7, 556-560. I

and II: (p) Bennett, M. A.; Kneen, W. R., Nyholm, R. S. J.

Organomet. Chem. 1971, 26, 293-303. I, (2-Ph₂PC₆H₄)CHdCHMe,

and II: (q) Interrante, L. V.; Nelson, G. V. Inorg. Chem. 1968, 7,

2059-2064. II and (2-Ph₂PC₆H₄)CH(Me)CHdCH₂: (r) Bennett, M.

A.; Kneen, W. R.; Nyholm, R. S. Inorg. Chem. 1968, 7, 552-556.

(2-Ph₂PC₆H₄)(CH₂)₃CHdCH₂: (s) Bennett, M. A.; Kouwenhoven, H.

W.; Lewis, J.; Nyholm, R. S. J. Chem. Soc. 1964, 4570-4577. P(C₆H₄-

CHdCH₂-2)₃and PhP(C₆H₄CHdCH₂-2)₂: (t) Hall, D. I.; Nyholm, R.

S. J. Chem. Soc., Chem. Commun. 1970, 488-4879. (u) Nyholm, R.

S.; Hall, D. I. J. Chem. Soc. A 1971, 1491-1493. (v) Hall, D. I.;

Nyholm, R. S. J. Chem. Soc., Dalton Trans. 1972, 804-809. I and

(2-Ph₂PC₆H₄)CHdCHPh: (w) Bennett, M. A.; Kapoor, P. N. J.

Organomet. Chem. 1987, 336, 257-269. Ph₂PCH₂SiMe₂(CHdCH₂):

(x) Alyea, E. C.; Meehan, P. R.; Ferguson, G.; Kannan, S. Polyhedron

1997, 16, 3479-3481.

We have recently reported about the synthesis and

coordination behavior of 1′-(diphenylphosphino)-1-vinylfer-

(5) Bertogg, A.; Togni, A. Organometallics 2006, 25, 622-630.

(6) Metallinos, C.; Szillat, H.; Taylor, N. J.; Snieckus, V. AdV. Synth.

Catal. 2003, 345, 370-382.

(7) (a) Bunz, U. H. F. J. Organomet. Chem. 1995, 494, C8-C11.

Examples of FcCHdCHR alkenes (R ) Me or Ph) substituted in

position 2 of the ferrocene unit are even less common. See, e.g.: (b)

Toma, Sˇ.; Kaluzayova, E. Chem. ZVesti 1969, 23, 540-552. (c)

Benedikt, M.; Schlo¨gl, K. Monatsh. Chem. 1978, 109, 805-822. (d)

Izumi, T.; Endo, K.; Saito, O.; Shimizu, I.; Maemura, M.; Kasahara,

A. Bull. Chem. Soc. Jpn. 1978, 51, 663-664.

(8) Abbenhuis, H. C. L.; Burckhardt, U.; Gramlich, V.; Togni, A.; Albinati,

A.; Mu¨ller, B. Organometallics 1994, 13, 4481-4493.

(9) Hayashi, T.; Mise, T.; Fukushima, M.; Kagotani, M.; Nagashima, N.;

Hamada, Y.; Matsumoto, A.; Kawakami, S.; Konishi, M.; Yamamoto,

K.; Kumada, M. Bull. Chem. Soc. Jpn. 1980, 53, 1138-1151.

(10) (a) Stille, J. K.; Su, H.; Hill, D. H.; Schneider, P.; Tanaka, M.;

Morrison, D. L.; Hegedus, L. S. Organometallics 1991, 10, 1993-

2000. This diphosphine was also obtained a side product from the

attempted synthesis of a chiral, azacrown-substituted ferrocenyldiphos-

phine: (b) Landis, C. R.; Sawyer, R. A.; Somsook, E. Organometallics

2000, 19, 994-1002. A related 1,1′-bis(alkenyl)-2,2′-diphosphine as

a precursor for chiral ferrocene diphosphine can be found in: (c) Kang,

J.; Lee, J. H.; Choi, J. S. Tetrahedron: Asymmetry 2001, 12, 33-35.

(14) Since all compounds are (S_p)-chiral, the descriptor specifying chirality

at the 1,2-disubstituted cyclopentadienyl plane is omitted for clarity.

(15) The isomer (R_p)-2 has been already mentioned in the literature as a

side product from diastereoselective synthesis of tetracyclic precursors

to vinblastine using (S,R_p)-1-[2-(diphenylphosphino)ferrocenyl]ethyl

acetate as a chiral auxiliary. For reference, see: Kuehne, M. E.;

Bandarage, U. K. J. Org. Chem. 1996, 61, 1175-1179.

(16) (a) Riant, O.; Samuel, O.; Kagan, H. B. J. Am. Chem. Soc. 1993, 115,

5835-5836. (b) Riant, O.; Samuel, O.; Flessner, T.; Taudien, S.;

Kagan, H. B. J. Org. Chem. 1997, 62, 6733-6745.

8786 Inorganic Chemistry, Vol. 45, No. 21, 2006

Ferrocene Alkenylphosphines

Scheme 1. Preparation of the Ligands

Figure 1. View of molecule 1 in the crystal structure of 1 showing

displacement ellipsoids at the 30% probability level. Selected geometric

parameters for molecule 1 [molecule 2]: C(1)-C(23) 1.455(3) [C(31)-

C(53) 1.463(2)], C(23)-O(1) 1.215(3) [C(53)-O(2) 1.219(2)], P(1)-C(2)

1.821(2) [P(2)-C(32) 1.817(2)], P(1)-C(11) 1.840(2) [P(2)-C(41) 1.836-

(2)], P(1)-C(17) 1.836(2) [P(2)-C(47) 1.835(2)] Å; C(2)-C(1)-C(23)

125.7(2) [C(32)-C(31)-C(53) 125.8(2)], C(1)-C(23)-O(1) 125.0(2)

[C(31)-C(53)-O(2) 123.4(1)]°; torsion angles C(23)-C(1)-C(2)-P(1)

7.1(3) [C(53)-C(31)-C(32)-P(2) 14.9(2)]°.

The prop-1-en-1-yl analogue, compound 3, was prepared

similarly. In this case, however, the Wittig reaction with the

in situ generated ylide Ph₃PdCHMe afforded a mixture of

double-bond configurational isomers with the Z-isomer

dominating (the (Z)-3:(E)-3 ratio as determined by NMR was

ca. 5:1). This isomer ratio is in accordance with the

stereochemical outcome usually observed for reactions with

triphenylphosphine-based Wittig reagents^17,18which, in turn,

indicates that the proximal phosphino group represents no

pronounced stereochemical bias for the course the alkenyl-

ation reactions involving aldehyde 1. Attempts to separate

the isomers by chromatography or crystallization failed due

to their similar solubility and retention characteristics. To

circumvent similar difficulties with isomer separation, the

2-phenyleth-1-en-1-yl derivative was prepared by Horner-

Wadsworth-Emmons reaction (HWE)^18,19(Scheme 1). Again,

in agreement with the stereoselectivity of the HWE olefi-

nation,¹⁸the respective phosphinoalkene 4 was isolated

exclusively as the E-isomer after chromatography and

crystallization from heptane.

Phosphinoalkenes 2-4 were characterized by the standard

analytical methods, and the solid-state structures of 1 and 2

were determined by single-crystal X-ray diffraction. The

formulation of 2-4 is in accordance with their spectral and

analytical data. In ¹H and ¹³C NMR spectra, the compounds

exhibit characteristic signals due to 1,2-disubstituted fer-

rocene framework and vinyl group (2) or 1,2-disubstituted

double bonds ((Z/E)-3 and (E)-4). The phosphine substituents

give rise to signals at δ_P≈ -21 in ³¹P NMR spectra.

The solid-state structures of 1 and 2 are shown in Figures

1 and 2, respectively, along with the relevant structural

parameters. The structures fully corroborate the expected

ones including absolute configuration at the disubstituted

cyclopentadienyl plane. The geometry of the (diphenylphos-

phino)ferrocenyl moieties in both compounds is very similar

and quite regular. In both cases, the carbon substituents

Figure 2. The molecular structure of (S_p)-2. Displacement ellipsoids are

shown at the 30% probability level. Selected geometric parameters: C(1)-

C(23) 1.463(2), C(23)-C(24) 1.323(3), P-C(2) 1.817(2), P-C(11) 1.838-

(2), P-C(17) 1.837(2) Å; C(2)-C(1)-C(23) 125.6(2), C(1)-C(23)-C(24)

126.4(2), P-C(2)-C(1) 123.5(1), C-P-C angles 98.68(7)-102.30(7)°;

torsion angle C(23)-C(1)-C(2)-P -3.4(2)°; ferrocene unit Fe-Cg(1)

1.6478(7), Fe-Cg(2) 1.6596(8) Å, Cp(1),Cp(2) 1.9(1)°. Definitions: Cp-

(1) [Cp(2)] are the cyclopentadienyl rings C(1-5) [C(6-10)]; Cg(1,2)

denote their respective centroids.

(aldehyde or vinyl group) are directed outward the phosphino

substituent while remaining nearly parallel with their parent

cyclopentadienyl ring, thus allowing for an efficient conjuga-

tion. This can be demonstrated by the angles subtended by

the CdO or CdC bonds and the Cp1 planes of 0.6(2)° for

molecule 1 [3.2(1)° for molecule 2] in 1 and 7.4(2)° in 2,

and further by the torsion angles C(2)-C(1)-C(23)-O(1)

-179.6(2)° [C(32)-C(32)-C(53)-O(2) 175.5(2)°] for the

aldehyde and C(2)-C(1)-C(23)-C(24) of -171.1(2)° for

2. Bond lengths within the carbon substituents are similar

to those in respectively Ph₂PfcCHO (fc ) ferrocene-1,1′-

diyl; CdO 1.213(4) Å)²⁰and Ph₂P(S)fcCHdCH₂(CdC

1.314(3) Å)¹¹or 1′,1′′′-divinylbiferrocene (CdC 1.300(7) Å).²¹

(17) Wittig, G.; Scho¨llkopf, U. Chem. Ber. 1954, 87, 1318-1330 and

references therein.

(18) Maryanoff, B. E.; Reitz, A. B. Chem. ReV. 1989, 89, 863-927.

(19) (a) Horner, L.; Hoffmann, H.; Wippel, J. H. G.; Klahre, G. Chem.

Ber. 1959, 92, 2499-2505. (b) Wadsworth, W. S., Jr.; Emmons, W.

D. J. Am. Chem. Soc. 1961, 83, 1733-1738. (c) Wadsworth, W. S.,

Jr. Org. React. 1977, 25, 73-253.

Inorganic Chemistry, Vol. 45, No. 21, 2006 8787

Sˇteˇpnicˇka and C´ısarˇova´

Scheme 2

Palladium Complexes with Ligand 2. The donor ability

of the simplest representative 2 was first studied in reactions

with palladium(II) complexes bearing ortho-metalated N,N-

benzylamine as a supporting ligand. Quite expectedly,

cleavage of halide bridges in the dinuclear complex 5 gave

complex 6 featuring 2 as a P-monodentate phosphine.

Chelate coordination was achieved upon changing the

palladium precursor to the cationic bis(acetonitrile) complex

7²²or, alternatively, by halide removal from 6 with silver(I)

perchlorate (Scheme 2).

The coordination of 2 via the phosphorus atom is clearly

manifested by low-field ³¹P NMR shifts (cf. the coordination

shifts, ∆ ) δ(complex) - δ(ligand), ∆_P(6) ) +52.7 and

∆_P(8) ) +51.3). On the contrary, the interaction between

the ligand vinyl moiety and the palladium center is difficult

to decide on from NMR spectra only since they exhibit no

significant changes for the double bond resonances. For

instance, the ¹³C NMR signals of the vinyl groups in 2, 6,

and 8 are found in narrow ranges of 100.93-112.36 (dCH₂)

and 132.24-134.15 (dCH) (cf. the data for the tungsten

complexes below). The ferrocene signals are little informative

also [see, e.g., δ_Cfor the phosphine/vinyl-bearing cyclopen-

tadienyl carbon atoms: 75.89/88.79 (2), 72.41/87.76 (6), and

n.o./90.25 (8)]. Likewise, the NMR signals due to the 2-

{(dimethylamino)methyl}phenyl (L^NC) ligands in 6 and 8 are

observed at similar positions but with differences between

chemical shifts of the diastereotopic NCH₂and NMe₂protons

larger in 8 that in 6 (6/8: ∆δ(NCH₂) 0.04/0.43, ∆δ(NMe₂)

0.20/0.95). The ⁴J_PHand ³J_PCcoupling constants for the NCH₂

and NMe₂groups^22,23allow one to formulate complexes 6

and 8 as having trans-P-N geometry. ESI mass spectra of

6 and 8 show prominent ions at m/z 636 attributable to [Pd-

(L^NC)(2)]⁺formed by either loss of chloride (6) or dissocia-

tion (8).

Figure 3. CD (top) and UV-vis spectra (bottom, 1 mm optical path) of

ligand 2 (dashed line) and its palladium(II) complexes 6 (solid line) and 8

(dotted line). For the latter case, the inset shows an expansion of the long-

wavelength region (1 cm optical path; i.e., 10-fold in the A-axis). The spectra

were recorded in methanol (1 mM solutions and 1 cm/1 mm optical paths

for the UV-vis spectra; roughly similar but varying concentrations for

individual compounds for the CD spectra).

CD spectra of free ligand 2 are strikingly different from

those of its palladium complexes 6 and 8 (Figure 3). At first

sight, the spectra could have been interpreted as belonging

to compounds with the opposite configuration at the stereo-

genic element (see, e.g., opposite signs of the Cotton effect

at around 475 nm). However, since the CD spectra reflect

the same planar chirality at the ferrocene unit, the reason

for the different response should be sought in the shift of

the electronic absorption bands upon coordination. This

assumption is supported by UV-vis spectra (Figure 3),

which are very similar for both palladium complexes but

differ markedly from that of 2.²⁴The presented results clearly

indicate that CD spectra of similar systems should be

interpreted with caution to avoid confusing conclusions.

The crystal structure of 8 was determined by X-ray

diffraction analysis. The molecular structure of the cation

(20) Sˇteˇpnicˇka, P.; Basˇe, T. Inorg. Chem. Commun. 2001, 4, 682-687.

(21) Dong, T.-Y.; Hwang, M.-Y.; Hsu, T.-L.; Schei, C.-C.; Yeh, S.-K. Inorg.

Chem. 1990, 29, 80-84.

(24) The similarity of the UV-vis and CD spectra of 6 and 8 may also

suggest similar species to be involved, formed by dissociation of 6

(at least partial) in the polar solvent (methanol). This explanation

cannot be simply ruled out albeit NMR data (∆_P) 52.7 in CD₃OD)

stand against it.

(22) Sˇteˇpnicˇka, P.; Lamacˇ, M.; C´ısaˇrova´, I. Polyhedron 2004, 23, 921-

928.

(23) Sˇteˇpnicˇka, P.; C´ısaˇrova´, I. Organometallics 2003, 22, 1728-1740.

8788 Inorganic Chemistry, Vol. 45, No. 21, 2006

Ferrocene Alkenylphosphines

ferrocene phosphines.^22,23As indicated by the ring-puckering

parameters²⁵(Q₂) 0.442(3) Å, φ₂) 222.7(4)°), the

palladacycle adopts an envelope conformation. The phenyl

ring C(25-30) which is a part of the cycle is rotated from

the plane comprising the Pd, P, N, and C(25) atoms (PdL₃)

by 19.8(1)°.

Structurally more interesting features can be seen within

phosphinoalkene part, where steric strain imposed by the

chelate coordination leads to deformation of both the

coordination sphere around palladium(II) and the ligand

molecule. The η²-coordinated double bond is tilted with

respect to the PdL₃plane at an angle of 69.8(2)°, and

consequently, the C(23)-Pd-C(25) and C(24)-Pd-C(25)

angles differ by as much as 20°. In addition, the double bond

coordinates to the palladium atom somewhat asymmetri-

cally: the Pd-C(23,24) bond lengths differ by about 0.15

Å and the center of the double bond (or Cg(3)) is shifted

with respect to the projection of the Pd-C(25) bond in the

trans position. Notably, the coordination causes only a negli-

gible elongation of the double bond (by only ca. 1% with

respect to uncoordinated 2). Indeed, this is in accordance

with the NMR data but contrasts with the structure of

[Pd{(2-Ph₂PC₆H₄)CHdCH₂-η²:κP}{(2-Ph₂PC₆H₄)CHd

CH₂-κP}], where the difference between the coordinated and

free double bond lengths amounts to 0.094 Å (or relatively

7%).^13k,26

Figure 4. Side (top) and top (bottom) views with respect to the

coordination plane of the complex cation [Pd(L^NC)(2-η²:κP)]⁺in 8.

Displacement ellipsoids are shown with 30% probability.

The coordination further changes the conformation of the

ligand. The C(23)-C(24) bond in 8 is rotated respect to the

Cp1 plane at an angle of 43.1(2)° (compare the torsion angle

C(2)-C(1)-C(23)-C(24) ) -52.5(4)° with that in unco-

ordinated 2), and simultaneously, the whole vinylphosphine

moiety becomes more compact via closure of the C(1)-

C(23)-C(24) and C(1)-C(2)-P angles (both by ca. 3°). The

C(23) atom binds symmetrically to the Cp1 ring, but the

C(2)-P bond is inclined toward the vinyl moiety: whereas

the difference of the C(2,5)-C(1)-C(23) angles is below

3°, that between C(3,1)-C(2)-P approaches 12°. In addition,

the donor atoms are bent from their parent cyclopentadienyl

plane (the perpendicular distances for the P and C(23) atoms

to the Cp1 plane are respectively 0.194(1) and 0.117(4) Å)

though without significant torsion at the C(1)-C(2) bond

(torsion angle C(23)-C(1)-C(2)-P is -4.8(4)°). The whole

ferrocene unit is rotated with respect to the PdL₃plane as

exemplified by the dihedral angle 27.5(2)° between the PdL₃

and Cp1 planes.

Table 1. Selected Interatomic Distances (Å) and Angles (deg) for 8^a,b

Pd-P

2.2729(6) P-C(2)

1.794(3)

1.823(3)

1.818(3)

1.481(5)

1.458(4)

1.502(4)

1.498(4)

Pd-N

2.150(2)

2.307(3)

2.477(3)

2.324(3)

2.022(3)

1.340(4)

1.470(4)

P-C(11)

Pd-Cg(3)

Pd-C(23)

Pd-C(24)

Pd-C(25)

C(23)-C(24)

C(1)-C(23)

P-C(17)

N-C(31)

N-C(32)

N-C(33)

C(26)-C(31)

P-Pd-Cg(3)

P-Pd-C(25)

N-Pd-Cg(3)

N-Pd-C(25)

N-C(31)-C(26)

87.89(8)

96.54(7)

95.1(1)

81.6(1)

108.4(3)

C(1)-C(23)-C(24) 123.3(2)

C(2)-C(1)-C(23)

C(5)-C(1)-C(23)

C(1)-C(2)-P

125.0(2)

127.6(2)

120.2(2)

131.9(2)

153.4(1)

C(3)-C(2)-P

C(24)-Pd-C(25)

C(23)-Pd-C(25) 173.71(9)

Fe-Cg(1)

Fe-Cg(2)

1.641(1)

1.654(2)

Cp(1),Cp(2)

4.5(2)

^aDefinitions are as follows. Ring planes: Cp(1), C(1-5); Cp(2), C(6-

10); Cg(1) and Cg(2) are the respective ring centroids. Cg(3) denotes the

midpoint of the η²-coordinated double bond C(23)dC(24). ^bStructural data

for the perchlorate counterion: Cl-O(1) 1.439(3), Cl-O(2) 1.445(3), Cl-

O(3) 1.428(3), Cl-O(4) 1.440(3) Å; O-Cl-O angles 108.9(2)-110.1(2)°.

Preparation and Structures of Tungsten(0) Carbonyls

Complexes with 2-4. The reaction between equimolar

amounts of 2 and [W(cod)(CO)₄] (cod ) η:²η²-cycloocta-

in the structure of 8 is shown in Figure 4, and the selected

structural data are given in Table 1. The structure confirms

the expected chelate coordination of the phosphinoalkene as

well as the trans-P-N disposition of the donors. To describe

the coordination geometry, we take the midpoint of the η²-

double bond (or Cg(3)) as the ligating site. Then, the

interligand angles span the range 81.6(1)-96.54(7)° with the

angles within both chelate rings being more acute that the

remaining ones. The Pd-X bonds length (X ) P, N, and

C(25)) as well as the geometry of the five-membered

palladacycle compare favorably with those observed for

related, structurally characterized complexes featuring other

(25) Cremer, D.; Pople, J. A. J. Am. Chem. Soc. 1975, 97, 1354-1358.

Ideal envelope conformation requires φ₂) 216°. N.B. The ring

puckering parameters should be considered informative only because

of the different bond lengths within the metallacycle.

(26) A closer look at the geometry of Pd(η²-RCHdCH₂) moieties in the

Cambridge Structural Database (CSD; 35 structures) revealed that there

is no pronounced correlation between the coordination distance (Pd-

Cg) and the CdC bond length. This is probably because an influence

of the double bond substituent (R) on the double bond length is

comparable with that of coordination. Nevertheless, the bond lengths

observed for 8 are in accordance with mean values from CSD.

Source: Cambridge Structural Database version 5.27 of Nov 2005

with updates of Jan 2006.

Inorganic Chemistry, Vol. 45, No. 21, 2006 8789

Sˇteˇpnicˇka and C´ısarˇova´

Scheme 3

limited stirring). Compounds (E)-11 and (E)-12 were sepa-

rated by column chromatography on silica gel. The former,

faster eluting complex was isolated as an orange solid which

was subsequently crystallized from heptane to yield (E)-11

as well-developed, red crystals, while the slightly more polar

(E)-12 was obtained in the form of an orange-yellow foam

possessing a strong tendency to adsorb reaction solvents.

The complexes could be clearly distinguished on the basis

of elemental analyses and NMR and IR spectra. Besides,

the structure of (E)-11 was independently corroborated by

1

X-ray diffraction analysis. In H and ¹³C NMR spectra,

complex (E)-11 shows the CHdCH resonances within the

usual double bond region (δ_C124.74 and 128.32),³⁰while

the spectra of its chelate counterpart (E)-12 display the same

signals at significantly higher fields (cf. δ_C75.38 and 86.53).

The ¹³C NMR spectra are also indicative of the carbonyl-

substitution pattern: compound (E)-11 exerts a pair of

1,5-diene) in refluxing toluene gave air-stable, crystalline

complex [W(CO)₄(2)] (9) in 91% isolated yield (Scheme 3).²⁷

The bidentate coordination of the phosphinoalkene (η²:κP)

in 9 was clearly inferred from NMR spectra and further

2

doublets due to four cis (δ_C197.73, J_PC) 7 Hz) and one

2

trans (δ_C198.97, J_PC) 22 Hz) tungsten-bonded carbonyl

ligands, while (E)-12 shows four well-separated, phosphorus-

coupled doublets with characteristic ¹⁸³W satellites between

δ_Pca. 201 and 213 in a pattern similar to that for 9. The

coordination shift observed in ³¹P NMR spectra for chelate

complex (E)-12 (∆_P) 46.6, ¹J_WP) 293 Hz) is much larger

1

corroborated by single-crystal X-ray diffraction. In H and

¹³C NMR spectra, the coordination is reflected mainly by a

considerable high-field shift of the double bond resonances,

the respective values being ∆_H(dCH) ) 0.55, ∆_C(dCH₂)

) 47.8, and ∆_C(dCH) ) 51.3. By contrast, the phosphine

resonance appears at a significantly lower field (∆_P) 45.0)

flanked with ¹⁸³W satellites (¹J_WP) 249 Hz).²⁸In IR spectra,

complex 9 shows characteristic strong carbonyl stretching

bands: a sharp band at 2022 cm^-1and broad, composite

bands at around 1920 and 1870 cm^-1.

1

than for (E)-11 (∆_P) 32.8, J_WP) 246 Hz), which is in

accordance with bidentate coordination of (E)-4 in the for-

mer case. The observed shifts are significantly larger than

those observed in [W(CO)₅(dppf-κP)], [(µ-dppf-1κP,2κP′)-

{W(CO)₅}₂] (both ∆_P) 28.5), and [W(CO)₄(dppf-κP,P′)]

(35.6; dppf ) 1,1′-bis(diphenylphosphino)ferrocene)³¹and

for the pair [W(CO)₅(Ph₂PfcSMe-κP)] (27.9) and [W(CO)₄-

(Ph₂PfcSMe-κ²S,P)] (36.3).^32,33In IR spectra of (E)-11 and

(E)-12, the major difference is in the positions of the highest

energy ν(CtO) band (2069 vs 2022 cm^-1).

Crystal Structures of 9, (Z/E)-10, and (E)-11. The

molecular structure of 9 as determined by single-crystal

X-ray diffraction is shown in Figure 5, and the relevant

structural parameters are collected in Table 2. The octahe-

dral coordination geometry at tungsten is rather asym-

metric as regards the metal-donor distances (W-P and

Replacing 2 with (Z/E)-3 in the above reaction leads to a

mixture of analogous chelate complexes, (Z/E)-10 (Scheme

3). Again, the isomers cannot be separated by conventional

methods because of their similar rentention and solubility

properties (see the crystal structure below). NMR spectra of

the reaction mixture recorded prior to chromatography or

crystallization indicate that the complexation reaction leaves

the original isomer ratio unaltered.

A similar reaction between (E)-4 and [W(cod)(CO)₄] is

more complicated, giving mixtures of two major products

(E)-11 and (E)-12 that differ by the coordination of the

phosphinoalkene and the number of ancillary carbonyl

ligands (Scheme 3). It is noteworthy that the product ratio

changes upon varying the reaction conditions. As expected,

higher temperatures and extended reaction times favor the

chelate complex (E)-12 while the formation of complex (E)-

11 requiring one CO molecule from the “reaction environ-

ment”²⁹is clearly facilitated at lower temperatures and under

stationary conditions (i.e., when no or only moderate

refluxing is maintained under static atmosphere and with

(29) The substitution reactions with [W(CO)₄(cod)] at elevated temperature

were always accompanied by a partial decomposition resulting into a

formation of dark insoluble materials. Decomposing carbonyl com-

plexes are the most likely source of free CO.

(30) The observed changes in the ¹H and ¹³C chemical shifts as compared

to uncoordinated (E)-4 can be attributed to electron density changes

at the double bond induced by donation from the conjugated

phosphorus substituent and an influence of the {W(CO)₅} moiety.

(31) Gan, K.-S.; Hor, T. S. A. 1,1′-Bis(diphenylphosphino)ferrocene-

Coordination Chemistry, Organic Syntheses, and Catalysis. In Fer-

rocenes-Homogeneous Catalysis, Organic Synthesis, Materials Sci-

ence; Togni, A., Hayashi, T., Eds.; VCH: Weinheim, Germany, 1995;

Chapter 1.2, pp 3-18.

(32) Gibson, V. C.; Long, N. J.; White, A. J. P.; Williams, C. K.; Williams,

D. J.; Fontani, M.; Zanello, P. J. Chem. Soc., Dalton Trans. 2002,

3280-3289.

(27) (a) In an attempt to prepare [W(CO)₅(2-κP)] we reacted equimolar

amounts of [W(CO)₅(MeCN)]^27band 2 in diethyl ether/heptane.

However, NMR analysis showed that no reaction took place at room

temperature after 24 h. (b) Koelle, U. J. Organomet. Chem. 1977,

133, 53-58.

(33) See also the coordination shifts observed for [W(CO)₅(L-κP)]

complexes featuring 1′-functionalized ferrocene phosphines: ∆_P28.4

for L ) Ph₂PfcCHO^20,33aand 28.5 for L ) Ph₂PfcCO₂H.^33b,c(a) Meca,

L.; Dvorˇa´k, D.; Ludv´ık, J.; C´ısarˇova´, I.; Sˇteˇpnicˇka, P. Organometallics

2004, 23, 2541-2551. (b) Podlaha, J.; Sˇteˇpnicˇka, P.; C´ısarˇova´, I.;

Ludv´ık, J. Organometallics 1996, 15, 543-550. (c) Lukesˇova´, L.;

Ludv´ık, J.; C´ısarˇova´, I.; Sˇteˇpnicˇka, P. Collect. Czech. Chem. Commun.

2000, 65, 1897-1910.

(28) Pregosin, P. S.; Kunz, R. W. ³¹P and C NMR Spectra of Transition

Metal Phosphine Complexes in NMR Basic Principles and Progress;

Diehl P., Fluck, E., Kosfeld, R., Eds.; Springer: Berlin, 1979; Vol.

16, Section G, pp 99-102 and references therein.

8790 Inorganic Chemistry, Vol. 45, No. 21, 2006

Ferrocene Alkenylphosphines

Further, the coordination causes lengthening of the double

bond (0.06 Å or 4.5% vs 2). To conform steric demands of

the central atom, the double bond is rotated from the Cp1

plane by as much as 64.2(3)° pointing away from the

ferrocene unit (cf. the C(2)-C(1)-C(23)-C(24) torsion

angle of -78.5(5)°). Similarly to 8, the P and C(23) atoms

are displaced above the Cp1 plane by 0.194(1) and 0.117(4)

Å, respectively, and the phosphorus atom is strongly inclined

toward the vinyl group (compare C(3)-C(2)-P 134.0(3)°

vs C(1)-C(2)-P 117.7(3)°). The W-C(23,24) distances

differ by only about 0.03 Å, and the geometry of the whole

“W(η²-CdC)” is similar to those in [W(CO)₃{(E)-(Ph₂-

PC₆H₄-2)CHdCHCH₂(C₆H₄PPh₂-2)-η²:κ²P,P′}] (W-C 2.403-

(8) and 2.387(9)/CdC 1.36(1) Å)³⁶and [W(O)Cl₂(PMe₂Ph)-

{CH₂dCHCH₂P(O)Ph₂)-η²:κO}] (2.210(6) and 2.228(6)/

1.415(8) Å)³⁷and W(CO)₅complexes with cyclic alkenes,

[W(CO)₅(η²-coe)] (coe ) cyclooctene; 2.451(5) and 2.425-

(4)/1.384(6) Å)³⁸and [W(CO)₅(η²-nbe)] (nbe ) norbornene;

2.50(2) and 2.51(2)/1.37(3) Å).³⁹

Figure 5. View of the molecular structure of 9. Displacement ellipsoids

enclose 30% probability.

Table 2. Selected Interatomic Distances (Å) and Angles (deg) for 9^a

For compound (Z/E)-10, the structural analysis clearly

confirmed the tendency of both isomeric forms to cocrys-

tallize. The alkenyl side chain appears statistically disordered,

being contributed from E- and Z-parts in about 1:3 ratio.

Furthermore, the structure suffers from a disorder at the

phenyl rings which both occupy two positions with nearly

equal abundance. As the disorder lowers the overall precision

of the structure determination (albeit without making the

structural data ambiguous), the structural data will be

discussed only briefly here.⁴⁰

The structure of (Z/E)-10 is shown in Figure 6 together

with the relevant structural data [see also Figure S1 (Sup-

porting Information)]. The coordination polyhedron around

tungsten is quite regular: the P-W-CO angles differ by

less than 3° from octahedral ones while the OC-W-CO

angles reflect bending of the W-C(34)-O(34) arm between

W-P

2.5328(9) W-C(31)

2.455(4) W-C(32)

2.427(4) W-C(33)

1.382(6) W-C(34)

1.488(6) C(31)-O(1)

1.801(4) C(32)-O(2)

1.837(4) C(33)-O(3)

1.835(4) C(34)-O(4)

1.646(2) Fe-Cg(2)

1.997(4)

2.046(4)

1.976(4)

2.033(4)

1.152(5)

1.129(5)

1.156(5)

1.146(5)

1.655(2)

W-C(23)

W-C(24)

C(23)-C(24)

C(1)-C(23)

C(2)-P

P-C(11)

P-C(17)

Fe-Cg(1)

Cp(1),Cp(2)

C(1)-C(23)-C(24) 119.3(4)

C(2)-C(1)-C(23) 126.6(4)

C(1)-C(2)-P

P-W-C(31)

P-W-C(32)

P-W-C(33)

P-W-C(34)

3.2(2)

P-W-Cg(3)

P-W-C(23)

P-W-C(24)

W-CtO

85.6(1)

79.5(1)

92.2(1)

173.6(4)-177.3(3)

117.7(3)

169.0(1)

93.6(1)

98.0(1)

85.3(1)

Cg(3)-W-C(31) 87.0(2)

Cg(3)-W-C(32) 92.6(2)

Cg(3)-W-C(33) 174.1(2)

Cg(3)-W-C(34) 98.8(2)

^aDefinitions are as follows. Ring planes: Cp(1), C(1-5); Cp(2), C(6-

10); Cg(1) and Cg(2) are the respective ring centroids. Cg(3) is the midpoint

of the η²-coordinated double bond C(23)dC(24).

(36) Bennett, M. A.; Corlett, S.; Robertson, G. B.; Steffen, W. L. Aust. J.

Chem. 1980, 33, 1261-1273.

W-{η²-C(23)dC(24)} vs four shorter W-CO bonds);

however, the interligand angles do not deviate much from

octahedral ones. The highest albeit still rather minor angular

deformation is observed for the W-C(34)-O(4) arm (angle

at C(34) ) 173.6(4)°), which is directed away from the

ferrocene unit and toward the phosphine substituent, obvi-

ously due to intramolecular steric interactions. In accordance

with the better donating ability (and a lower π-acceptor

power) of the alkene and phosphine donors as compared with

the carbonyls, the W-C(31,33) are slightly shorter than the

W-C(32,34) bonds while the respective C-O bond lengths

follow the opposite but less pronounced trend. The W-P

distance of 2.5328(9) Å corresponds to those in [W(CO)₅-

(dppf-κP)] (2.563(2) Å),³⁴[(OC)₅WdC(NEt₂)fcPPh₂W(CO)₅]

(2.545(1) Å),^33aand ferrocene chelates [W(CO)₄(Ph₂PfcSMe-

κ²S,P)] (2.538(1) Å)³²and [W(CO)₄(Ph₂PfcC(Y)-κ²C¹,P)] (Y

) OMe, 2.550(6) Å;³⁵Y ) NEt₂, 2.5391(9) Å^33a).

(37) Brock, S. L.; Mayer, J. M. Inorg. Chem. 1991, 30, 2138-2143.

(38) Grevels, F.-W.; Jacke, J.; Klotzbu¨cher, W. E.; Mark, F.; Skibbe, V.;

Schaffner, K.; Angermund, K.; Kru¨ger, C.; Lehmann, C. W.; O¨ zkar,

S. Organometallics 1999, 18, 3278-3293.

(39) Go´rski, M.; Kochel, A.; Szyman˜ska-Buzar, T. Organometallics 2004,

23, 3037-3046.

(40) Crystallographic data: brown fragment from the reaction batch (0.04

× 0.07 × 0.14 mm³); tetragonal, space group P4₁2₁2 (No. 92); a )

b ) 10.7034(4), c ) 46.411(2) Å; T ) 150(2) K; Z ) 8; V ) 5317.0-

(4) Å³; D ) 1.764 g mL^-1; µ(Mo KR) ) 4.962 mm^-1(corrected for

absorption; transmission factor range, 0.445-0.708). Oxford KM4

CCD diffractometer: 29 441 diffractions (θ e 26.6°) merged to 5509

unique of which 3987 were regarded as observed (I > 2σ(I); R_int

4.17%). Final R-indices: R ) 4.44 and wR ) 4.92% (all data), R )

2.67% (observed data). Residual electron density: 0.68, -0.50 e Å^-3

)

.

CCDC: deposition no. 604813. The structure was solved and refined

as indicated in Experimental Section with the following restraints: The

different alkenyl moieties were refined as two independent contributing

parts with the C(23) pivot atom. C(24a,b) and C(25a,b) were refined

isotropically, the trans-component having fixed C(23)-C(24b) and

C(24b)-C(25b) bond lengths. The refinement resulted in (E):(Z)

occupancies in ca. 1:3 ratio. Phenyl ring carbons were refined over

two positions with isotropic displacement parameters and geometry

constrained to an ideal hexagon (C-C ) 1.39 Å; the refinement

converged to nearly 50:50 occupancies for both rings). In addition,

several atom pairs from the complementary moieties were included

in the model as having identical displacement parameters. All hydrogen

atoms were included in calculated positions and refined using the riding

model.

(34) Phang, L.-T.; Au-Yeung, S. C. F.; Hor, T. S. A.; Khoo, S. B.; Zhou,

Z.-Y.; Mak, T. C. W. J. Chem. Soc., Dalton Trans. 1993, 165-172.

(35) Butler, I. R.; Cullen, W. R.; Einstein, F. W. B.; Willis, A. C.

Organometallics 1985, 4, 603-604.

Inorganic Chemistry, Vol. 45, No. 21, 2006 8791

Sˇteˇpnicˇka and C´ısarˇova´

Figure 7. View of molecule 1 in the structure of (E)-11 showing

displacement ellipsoids at the 30% probability level. Only one orientation

of the disordered cyclopentadienyl ring is shown for clarity. Note: the

labeling scheme for molecule 2 is similar with the first digit in the respective

atom label changed to two.

Figure 6. View of the molecular structure of (Z/E)-10. For clarity, the Z

(solid line, “a”) and E (dashed line, “b”) alkenyl sidearms are shown without

bonds to tungsten and only the pivotal atoms from both disordered phenyl

rings are included. Displacement ellipsoids are scaled to the 20% probability

level. Selected data: W-P 2.520(1), W-C(23) 2.482(4), W-C(24a) 2.560-

(9), W-C(24b) 2.42(2), W-C(31) 1.963(6), W-C(32) 1.995(6), W-C(33)

1.969(6), W-C(34) 2.007(5), C(23)-C(24a) 1.33(1), C(23)-C(24b) 1.37

(constrained), C(24a)-C(25a) 1.48(1), C(24b)-C(25b) 1.55 (constrained)

Å; P-W-C(31) 176.4(2), P-W-C(32) 92.5(2), P-W-C(33) 92.5(2),

P-W-C(34) 92.8(1), C(31)-W-C(32) 89.1(3), C(31)-W-C(33) 90.8-

(2), C(31)-W-C(34) 86.0(2), C(32)-W-C(33) 87.4(2), C(32)-W-C(34)

171.4(2), C(33)-W-C(34) 85.7(2), C(1)-C(23)-C(24a) 125.1(6), C(1)-

C(23)-C(24b) 106.5(9), C(23)-C(24a)-C(25a) 120.4(7), C(23)-C(24b)-

C(25b) 128(2)°. For alternative drawings, see the Supporting Information.

while the C(n11)-P-C(n17) angles appear practically

bisected by the same planes. The C(n23)-C(n24) double

bonds show lengths similar to that in (E)-stilbene (1.334 Å

at 150 K)^42,43and exhibit no notable torsion attributable to

their trans-disposed substituents (the C(n01)-C(n23)-

C(n24)-C(n25) dihedral angles are -176.2(4)° [-175.6-

(4)°]). However, the whole â-styryl groups are located above

the Cp1 plane and the phenyl and Cp1 rings are far from

coplanar. This can be demonstrated by the distances of the

C(n24) atoms from the Cp1 planes of 0.396(4) Å [0.278(4)

Å] and the dihedral angles between the phenyl and Cp1

planes of 44.3(2)° [41.9(2)°].

Electrochemistry. Electrochemical behavior was studied

by cyclic voltammetry on a stationary platinum disk and

voltammetry on a rotating platinum disk electrode (RDE) in

dichloromethane solutions containing the analyte (ca. 5 ×

10^-4M) and 0.1 M Bu₄NPF₆as the supporting electrolyte.

The potentials observed for ligands 2 and (E)-4 and their

tungsten complexes (9, (E)-11, and (E)-12) in the anodic

region given relative to ferrocene/ferrocenium reference are

summarized in Table 4.

Phosphinoalkene 2 undergoes a diffusion-controlled, one-

electron reversible oxidation at 0.11 V attributable to the

ferrocene/ferrocenium couple (Figure 8d). The position of

this wave, indicating a less easy oxidation of 2 than that of

ferrocene itself, corresponds with a prevailing electron-

accepting nature of the ferrocene substituents (σ_P(PPh₂) )

0.19, σ_P(CHdCH₂) ) -0.04).⁴⁴On going from 2 to chelate

complex 9, the ferrocene/ferrocenium wave shifts by 320

mV anodically, which clearly points to an electron density

lowering at the ferrocene unit upon formation of the dative

the C(31) and C(33) atoms, clearly attributable to steric

interactions with the ferrocene unit (see above). Unlike 9,

however, complex (Z/E)-10 shows very similar W-CO bond

lengths. Interestingly, the structure allows for a comparison

of the geometry of the W(η²-CdC) moieties that involve

double bonds with the opposite configuration. The moieties

seem to differ mainly from steric reasons. Having the

ferrocene-bonded carbon C(23) as a common pivot [W-C(23)

2.482(4) Å], the individual double bonds diverge so that the

distance from tungsten of the C(24) carbon is larger for the

Z-configured double bond, where one can expect an increased

crowding due to the methyl substitutent [W-C(24a) is 2.560-

(9) while W-C(24b) is 2.42(2) Å; cf. C(24a)‚‚‚C(24b) 0.53-

(2) Å and see Figure S2].

The X-ray diffraction analysis of (E)-11 (Figure 7, Table

3) showed the compound to crystallize with two independent

molecules in the asymmetric unit, differing only slightly in

mutual orientation of the flexible molecular parts (“Ph₂PW-

(CO)₅”). The coordination polyhedrons around tungsten atoms

in both structurally independent molecules are again very

regular except that the W-P distances are longer that the

bonds to the five carbonyls. Similarly to 9, the donating

ability of the phosphine group is reflected by relative short-

ening of the W-C(n35) bonds (n ) 1 and 2; trans influence)

but has virtually no effect on the C-O bond lengths.

Coordination of the phosphinoalkene as a simple phos-

phine in (E)-11 is clearly reflected on the overall molecular

geometry: the bulky ferrocene “substitutents” (Ph₂PW(CO)₅

and (E)-CHdCHPh) are rotated away from each other to

relieve their possible steric interactions. The W-P bonds

are nearly parallel with the Cp1 planes 4.8(2)° [4.3(2)°]⁴¹

(41) The numerical values are given as follows: molecule 1 [molecule 2].

Where appropriate, we use generally defined parameters with variable

indexes (n ) 1 for molecule 1, n ) 2 for molecule 2).

(42) The bond distance was retrieved from the Cambridge Structural

Database. For the original reference, see: Harada J.; Ogawa, K. J.

Am. Chem. Soc. 2001, 123, 10884-10888.

(43) Complex [PhCtW(η⁵-C₅HPh₄){(E)-(Ph₂PC₆H₄-2)CHdCHPh-η²:κP)]

where a similar (styryl)phosphine coordinates as an η²:κP-chelate

shows the CdC bond length of 1.450(7) Å: Cairns, G. A.; Carr, N.;

Green, M.; Mahon, M. M. Chem. Commun. 1996, 2431-2432.

(44) Hansch, C.; Leo, A.; Taft, R. W. Chem. ReV. 1991, 91, 165-195.

8792 Inorganic Chemistry, Vol. 45, No. 21, 2006

Ferrocene Alkenylphosphines

Table 3. Selected Interatomic Distances (Å) and Angles (deg) for (E)-11^a

param

molecule 1 (n ) 1)

molecule 2 (n ) 2)

param

molecule 1 (n ) 1)

molecule 2 (n ) 2)

W(n)-P(n)

2.562(1)

2.044(5)

1.138(7)

2.039(4)

1.141(5)

2.034(4)

1.147(5)

2.054(5)

1.141(6)

1.994(5)

1.145(6)

178.1(1)

2.547(1)

2.048(5)

1.151(6)

2.048(4)

1.138(5)

2.044(4)

1.139(5)

2.040(4)

1.143(5)

1.985(4)

1.161(5)

175.0(1)

P-C(n02)

1.820(4)

1.832(4)

1.835(4)

1.464(6)

1.329(6)

1.461(6)

123.7(4)

127.5(4)

129.3(4)

1.817(4)

1.843(4)

1.825(4)

1.460(6)

1.323(6)

1.475(6)

127.3(4)

125.1(4)

127.1(4)

W(n)-C(n31)

P-C(n11)

C(n31)-O(n31)

W(n)-C(n32)

P-C(n17)

C(n01)-C(n23)

C(n23)-C(n24)

C(n24)-C(n25)

C(n01)-C(n23)-C(n24)

C(n23)-C(n24)-C(n25)

C(n02)-C(n01)-C(n23)

Fe(n)-Cg(n1)

C(n32)-O(n32)

W(n)-C(n33)

C(n33)-O(n33)

W(n)-C(n34)

C(n34)-O(n34)

W(n)-C(n35)

1.638(2)

1.673(3)/1.608(2)

5.6(3)/6.6(3)

1.644(2)

1.663(1)/1.675(1)

4.0(2)/6.5(2)

C(n35)-O(n35)

Fe(n)-Cg(n2)^c

P(n)-W(n)-C(n35)^b

Cp(n1),Cp(n2)^c

^aDefinitions of the ring planes: Cp(n1), C(n01-n05); Cp(n2), C(n06-n10) [Cg(n1) and Cg(n2) are the respective ring centroids]; Ph(n1), C(n25-n30).

^bOther ligand angles: P(1)-W(1)-C(13m) 88.9(1)-94.0(1)°, P(2)-W(2)-C(23m) 90.4(1)-93.2(1)°, m ) 1-4. Other angles: W(1)-C(13l)-O(13l) 176.0(4)-

178.7(3)°, W(2)-C(23l)-O(23l) 175.4(4)-178.0(4)°, l ) 1-5. ^cValues for two refined positions of the disordered cyclopentadienyl ring are given.

Table 4. Cyclic Voltammteric Data for Ligands 2 and 4 and Their

The presence of the W(CO)₄moiety in 9 is further

reflected by an additional wave at 0.83 V (E_pa) due to a

Tungsten-Carbonyl Complexes^a

compd

E°′(I) (V)

∆E_p(I) (mV)

E°′(II) (V)

∆E_p(II) (mV)

tungsten-centered oxidation. The height of the wave is about

double that of the first oxidation, indicating a two-electron

process.⁴⁶The oxidation is irreversible at all scan rates

employed (up to 500 mV s^-1). However, it remains diffusion

controlled as established by linear dependence of the anodic

peak current (i_pa) on the square root of the scan rate (V; i_pa

V^1/2)⁴⁷and, above all, does not affect the preceding

ferrocene/ferrocenium oxidation. Such a redox response

parallels the behavior of [W(CO)₆], which is oxidized at

platinum electrode in a diffusion-controlled, irreversible

bielectronic process (ECE mechanism) at around 1.13 V (in

MeCN solution).⁴⁸Complexes [W(CO)₅(L-κP)] mentioned

above undergo similar oxidation at higher potentials: L )

FcPPh₂(0.97 V; Fc ) ferrocenyl) and Ph₂PfcCO₂H (0.98

V), which again corresponds with a replacement of two

carbonyls with less π-accepting “donors” in 9.⁴⁹

2

4

9

0.11

80

90

80

70

80

0.085

0.230

0.235

0.22

0.83^b

1.07^b

0.70

(E)-11

(E)-12

80

^aThe potentials are given relative to ferrocene/ferrocenium. E°′ is the

formal redox potential determined from cyclic voltammetry performed on

dichloromethane solutions containing ca. 5 × 10^-4M analyte and 0.1 M

Bu₄NPF₆at 100 mV/s scan rate. E°′ ) 1/2(E_pa+ E_pc), where E_paand E_pc

denote the anodic and cathodic peak potentials, respectively. For all

reversible redox processes, the E°′ values were identical with the half-wave

potentials (E_1/2) determined from voltammetry at Pt-RDE (see Experimental

Section). Separation of the cyclovoltammetric peak potentials, ∆E_p, is

defined as follows: ∆E_p) E_pa- E_pc. ^bIrreversible vawe. E_pais given.

The series involving ligand (E)-4 is more complete (Figure

8a-c). Similarly to 2, compound (E)-4 undergoes reversible

ferrocene-centered oxidation. In accordance with the overall

substituent effect (σ_P(CHdCHPh) ) -0.07),⁴⁴the observed

redox potential is very slightly lower than for 2. Oxidation

pattern observed for the pentacarbonyl complex (E)-11 is

analogous to the behavior of its [W(CO)₅(L-κP)] counterparts

(see above) in that it undergoes a reversible oxidation at the

ferrocene unit followed by irreversible multielectron, tungsten-

centered oxidation at ca. 1.07 V. Finally, compound (E)-12

follows the oxidation sequence observed for 9 (though at

lower potentials) with only exception in that the second

oxidation shows clear signs of electrochemical quasi-

(45) Kotz, J. C.; Nivert, C. L., Lieber, J. M.; Reed, R. C. J. Organomet.

Chem. 1975, 91, 87-95.

(46) The same applies to voltammetric waves observed at Pt-RDE.

(47) The anodic peak current (E_pa) shifts slightly to higher potentials upon

raising the scan rate.

(48) (a) Pickett, C. J.; Pletcher, D. J. Chem. Soc., Dalton Trans. 1975,

879-886. The E_pvalue was recalculated from the original reference

(E_p) +1.53 V vs SCE in MeCN containing 0.2 M Bu₄NBF₄) taking

E°′(ferrocene/ferrocenium) ) 0.40 V as obtained in acetonitrile with

0.1 M Bu₄NPF₆. For a reference, see: (b) Connelly, N. G.; Geiger, E.

Chem. ReV. 1996, 96, 877-910.

(49) Under similar conditions, complex [W(CO)₅(dppf-κP)] shows two

successive oxidation at 0.34 V (ferrocene/ferrocenium, reversible) and

1.00 V (W-centered, irreversible) but with similar peak currents: Ohs,

A. C.; Rheingold, A. L.; Shaw, M. J.; Nataro, C. Organometallics

2004, 23, 4655-4660.

Figure 8. Cyclic voltammograms in anodic region for (E)-4 (a), 10 (b),

(E)-11 (c), 2 (d), 6 (e), and 8 (f) as recorded on a platinum disk electrode

at the scan rate 100 mV s^-1. For conditions, see Table 4. For (E)-11, an

asterisk indicates a minor return peak attributable to adsorption or

decomposition products.

bonds. The magnitude of the coordination shift is strikingly

higher than that observed for P-monodentate ferrocene

ligands: [W(CO)₅(L-κP)], where L ) FcPPh₂(190 mV)⁴⁵

and Ph₂PfcCO₂H (180 mV),^33cwhich can be ascribed to

coordination of 2 as a bidentate chelating donor.

Inorganic Chemistry, Vol. 45, No. 21, 2006 8793

Sˇteˇpnicˇka and C´ısarˇova´

reversibility: while the oxidation appears fully irreversible

at 20 mV/s (the ratio of the peak currents, i_pc/i_pa) 0), an

increase of the scan rate results in an increase of the i_pc/i_pa

ratio up to values close to unity at 500 mV/s. Such behavior

is very likely invoked by chemical complications associated

with the electrochemical oxidation that (relatively slowly)

consume the electrogenerated species. Remarkably, the

irreversibility of the metal-centered oxidation in (E)-11 or

(E)-12 does not influence the redox response of the ferrocene/

ferrocenium couple.

carbonyl complexes, the ferrocene alkenylphosphines coor-

dinate as P-monodentate or η²:κP-chelating donors, similarly

to their organic counterparts. A conversion of monodentate

2 into its chelate form was established for the pair of

palladium(II) complexes 6 and 8. The structural data col-

lected indicate that coordination in either mode is facilitated

by flexibility of the donor groups attached to the rigid

ferrocene scaffold. Further studies on the reactivity of

ferrocene alkenylphosphines are currently under way.

Experimental Section

The redox behavior of palladium complexes 6 and 8 is

markedly different from the tungsten complexes. Compound

8 shows only single oxidation within the experimentally

accessible region (E°′ ) 0.43 V; Figure 8f). The wave can

be ascribed one-electron, reversible oxidation at the ferrocene

moiety and occurs shifted by 320 mV anodically as compared

with uncoordinated 2 (Figure 8d).⁵⁰As shown in Figure 8e,

the anodic pattern observed for 6 is more complicated. In

the anodic region, the complex first undergoes a diffusion-

controlled reversible, one-electron oxidation at 0.155 V,

clearly attributable to ferrocene-centered oxidation. In ac-

cordance with 6 being a neutral complex that possesses an

additional (chloride) ligand, the wave is shifted by only +45

mV vs 2. At higher potentials, the monooxidized species

undergoes two successive, well-separated oxidations at 0.43

V (∆E_p) 60 mV) and 0.69 V (∆E_pca. 80 mV).⁵¹Since the

second oxidation is found at exactly the same position as

the only wave observed for 8, one can assume some chemical

reactions following the prior ferrocene oxidation to generate

another electroactive species, possibly similar to 8.

General Comments. Unless noted otherwise, the syntheses were

performed under an argon atmosphere and with an exclusion of

the direct daylight. Tetrahydrofuran (THF) was distilled from

potassium-benzophenone ketyl. Toluene, diethyl ether, and hexane

were dried over sodium or potassium metals and distilled. Dichlo-

romethane was predried with anhydrous potassium carbonate and

then distilled from calcium hydride. Compounds 1,¹⁶5,⁵³and 7²²

were synthesized by the literature procedures. Other chemicals and

solvents were used as received from commercial sources (Fluka,

Aldrich; solvents from Lach-Ner). The reported yields are not

optimized.

NMR spectra were measured on a Varian UNITY Inova 400

spectrometer (¹H, 399.95; ¹³C, 100.58; ³¹P, 161.90 MHz) at 298

K. Chemical shifts (δ/ppm) are given relative to internal tetra-

methylsilane (¹H and ¹³C) or an external 85% aqueous H₃PO₄(³¹P).

IR spectra were recorded on an FT IR Nicolet Magna 760

instrument in the range of 400-4000 cm^-1. Mass spectra were

obtained on a Varian 3400/Finnigan MAT INCOS (GC-EI MS) or

ZAB-SEQ VG Analytical (direct inlet EI, FAB and HR MS

analyses) spectrometers. Electrospray (ESI) mass spectra were

recorded for methanol solutions on a Bruker Esquire 3000

spectrometer. CD spectra were obtained on a JASCO J-810

spectrometer (methanol solutions: c ) 1.34 mM for 2, 0.78 mM

for 6, and 0.75 mM for 8) while UV-vis spectra were recorded in

the same solvent on a Unicam UV 300 spectrometer (c ) 1.0 mM,

l ) 1, and 10 mm). Melting points were determined on a Kofler

apparatus and are uncorrected.

Electrochemical measurements were performed on a multipur-

pose polarograph PA3 interfaced to a model 4103 XY recorded

(Laboratorn´ı prˇ´ıstroje, Prague) at room temperature using a standard

three-electrode cell: rotating or stationary platinum disk working

electrode (1 mm diameter), platinum sheet auxiliary electrode, and

saturated calomel electrode (SCE) reference electrode, separated

from the analyzed solution by a salt bridge filled with 0.1 M Bu₄-

NPF₆in dichloromethane. The samples were dissolved in dichlo-

romethane (Merck, p.a.) to give ca. 5 × 10^-4M concentration of

the analyte and 0.1 M Bu₄NPF₆(supporting electrolyte; Fluka,

purissimum for electrochemistry). The samples were deaerated with

argon prior to the measurement and then kept under an argon blan-

ket. Cyclic voltammograms were recorded at stationary platinum

disk electrode (scan rates 20-500 mV/s), while the voltammograms

were obtained at rotating disk electrode (500 rpm, scan rates 10-

100 mV/s). Note: the redox potentials in Table 4 and text are given

relative to ferrocene/ferrocenium reference whereas Figure 8 shows

the curves “as recorded”, i.e., with SCE as the reference.

Concluding Remarks

Ferrocene-based, planar-chiral alkenylphosphines 2-4 are

accessible conveniently and in very good yields by olefina-

tion of the chiral phosphinoaldehyde 1. Depending on the

alkenylation procedure, the compounds can be obtained as

double bond configurational isomers; however, methods

leading to isomer mixtures should be avoided due to

difficulties with isomer separation. The alkenylphosphines

represent the first organometallic analogues⁵²to the known

organic alkenyl-substituted triphenylphosphines.¹³As dem-

onstrated for the series of palladium(II) and tungsten(0)-

(50) The potential shift is similar to that observed for the pair dppf/[PdCl₂-

(dppf)] as determined in 1,2-C₂H₄Cl₂(E_pa) 0.64 V/E°′ ) 1.03 V vs

SCE)^50aand MeCN solutions (E_pa) 0.51 V/E°′ ) 0.88 V vs SCE).^50b

(a) Corain, B.; Longato, B.; Favero, G.; Ajo´, D.; Pilloni, G.; Russo,

U.; Kreissl, F. R. Inorg. Chim. Acta 1989, 18, 583-590. (b)

Housecroft, C. E.; Owen, S. M.; Raithby, P. R.; Shayjk, B. A. M.

Organometallics 1990, 9, 1617-1623.

(51) The observed pattern does not change significantly with the scan rate

(20-500 mV/s) or upon repeated cycling. When the sample is scanned

with switching potential set before the second oxidation, the first wave

is observed with full reversibility (i_pa

ν

^1/2, i_pa/i_pc≈ 1). Cycling in

the whole accessible anodic region (i.e. with the switching pontential

set after the third oxidation wave) lowers the reversibility of the first

wave as indicated by i_pa> i_pc. In the voltammogram recorded at RDE,

the wave due to the ferrocene oxidation exerts the normal sigmoidal

shape and a height corresponding to one electron exchanged while

the third oxidation is observed as a tilted irreversible wave of

approximately half-height of the first wave. The second wave from

cyclic voltammogram is not reflected at all in the voltammogram at

RDE.

(52) It is noteworthy that planar-chiral arene-tricarabonylchromium(0)

complexes, [Cr(CO)₃(η⁶-C₆H₄(X-1)(PPh₂-2))], where X ) CHdCH₂

and CH₂CHdCH₂, were reported. However, no coordination study

was made. Christian, P. W. N.; Gil, R.; Mun˜iz-Ferna´ndez, K.; Thomas,

S. E.; Wierzchleyski, A. T. J. Chem. Soc., Chem. Commun. 1994,

1569-1570.

(53) Cope, A. C.; Friedrich, E. C. J. Am. Chem. Soc. 1968, 90, 909-913.

8794 Inorganic Chemistry, Vol. 45, No. 21, 2006

Ferrocene Alkenylphosphines

Preparation of (S_p)-2-(Diphenylphosphino)-1-vinylferrocene

(2). Butyllithium (2.2 mL, 2.5 M in hexanes, 5.5 mmol) was slowly

introduced to a stirred suspension of [PPh₃Me]Br (2.146 g, 6.0

mmol) in THF (50 mL) with cooling in an ice bath. The white

phosphonium salt dissolved almost completely to give an orange

solution, which later turned to bright yellow. After stirring of the

solution at 0 °C for 30 min, a solution of (S_p)-2-(diphenylphos-

phino)ferrocenecarboxaldehyde (1; 1.995 g, 5.0 mmol) in THF (25

mL) was added to the formed ylide and the cooling bath was

removed. The reaction mixture was stirred for another 6 h at room

temperature and then quenched by addition of saturated aqueous

NaHCO₃and stirring for another 15 min. The orange organic phase

was separated, washed successively with saturated aqueous NaHCO₃

and NaCl solutions, dried over MgSO₄, and evaporated under

reduced pressure. The oily residue was purified by column

chromatography (silica gel, 1:2 hexane-diethyl ether). The major

band of the product is eluted first, followed by a minor band of the

respective phosphine oxide. Evaporation of the first fraction under

vacuum (finally at 0.1 Torr for 1 h) gave the phosphinoalkene as

an amber oil, which was immediately dissolved in hot heptane.

Subsequent crystallization of the solution at room temperature and

then at -18 °C gave analytically pure 2 as a rusty brown crystalline

solid, which was isolated by suction. Yield: 1.750 g (88%).

solid, which was isolated by decantation and dried under vacuum.

Yield: 235 mg (57%). The product was shown NMR spectroscop-

ically to be a mixture of double bond isomers, (Z)-3 and (E)-3, in

ca. 5:1 ratio. Attempts to fully separate the double-bond isomers

by either chromatography or crystallization failed.

HR MS (EI): calcd for C₂₅H₂₃⁵⁶FeP, 410.0887; found 410.0899.

3

Major isomer, (Z)-3: ¹H NMR (CDCl₃) δ 1.79 (dd, J_HH) 7.1,

⁴J_HH) 1.7 Hz, 3 H, Me), 3.67 (m, 1 H, C₅H₃), 4.03 (s, 5 H, C₅H₅),

3

4.33 (apparent t, 1 H, C₅H₃), 4.70 (m, 1 H, C₅H₃), 5.58 (dq, J_HH

3

4

) 11.4, 7.1 Hz, 1 H, dCHMe), 6.43 (ddq, J_HH) 11.4, J_HH

≈

⁴J_PH≈ 1.7 Hz, 1 H, CHdCHMe), 7.07-7.59 (m, 10 H, PPh₂);

³¹P{¹H} NMR (CDCl₃) δ -20.8. Minor isomer, (E)-3: ¹H NMR

(CDCl₃) δ 1.69 (dd, ³J_HH) 6.6, ⁴J_HH) 1.7 Hz, 3 H, Me), 3.68 (m,

1 H, C₅H₃), 4.00 (s, 5 H, C₅H₅), 4.28 (apparent t, 1 H, C₅H₃), 4.66

(m, 1 H, C₅H₃), 5.86 (ddq, ³J_HH) 15.6, ⁵J_PH) 1.1, ³J_HH) 6.6 Hz,

1 H, dCHMe), 6.39 (ddq, J_HH) 15.6, J_HH≈ J_PH≈ 1.7 Hz, 1

H, CHdCHMe), 7.07-7.59 (m, 10 H, PPh₂); ³¹P{¹H} NMR

(CDCl₃): δ -21.2.

3

4

Preparation of (E,S_p)-2-(Diphenylphosphino)-1-(2-phenylethen-

1-yl)ferrocene ((E)-4). Butyllithium (0.8 mL 2.5 M in hexanes,

2.0 mmol) was added to a solution of PhCH₂P(O)(OEt)₂(0.65 mL,

3.1 mmol) in THF (25 mL) with cooling to -78 °C and the resulting

mixture stirred for 30 min. A solution of 1 (402 mg. 1.0 mmol) in

THF (25 mL) was introduced, the cooling bath was removed, and

the mixture stirred for 90 min at room temperature and, finally,

slowly brought to 60 °C and stirred at this temperature overnight.

The reaction was terminated by addition of saturated aqueous NaCl

solution and the mixture diluted with diethyl ether. The organic

layer was separated, washed with brine, dried (MgSO₄), and

evaporated under vacuum. The brown residue was purified by

column chromatography on silica gel with hexane-diethyl ether

(4:1). The first orange band was collected and evaporated. The solid

residue was dissolved in hot heptane (15 mL) and the solution

filtered while warm and crystallized at -18 °C to give a brown

crystalline solid. The separated product was filtered off, washed

with a little pentane, and dried under vacuum. Yield of (E)-4: 286

mg (61%), rusty brown crystalline solid.

1

Mp: 140-141 °C (heptane). H NMR (CDCl₃): δ 3.71 (dt, 1

H, C₅H₃), 4.02 (s, 5 H, C₅H₅), 4.33 (dt, 1 H, C₅H₃), 4.73 (dt, 1 H,

3

2

C₅H₃), 5.03 (dd, J_HH) 10.8, J_HH) 1.5 Hz, 1 H, dCH₂), 5.38

3

2

(dt, J_HH) 17.5, J_HH≈ J_PH≈ 1.5 Hz, 1 H, dCH₂), 6.07 (ddd,

³J_HH) 10.8, 17.5, J_PH) 2.2 Hz, 1 H, dCH), 7.11-7.59 (m, 10 H,

PPh₂). ¹³C{¹H} NMR (CDCl₃): δ 67.71 (d, J_PC) 3 Hz, CH of

C₅H₃), 70.02 (CH of C₅H₃), 70.34 (C₅H₅), 71.98 (d, J_PC) 4 Hz,

1

2

CH of C₅H₃), 75.56 (d, J_PC) 9 Hz, CP of C₅H₃), 88.79 (d, J_PC

) 21 Hz, CCHdCH₂of C₅H₃), 112.36 (d, J_PC≈ 2 Hz, dCH₂),

127.72, 128.06 (d, J_PC) 6 Hz), 128.12 (d, J_PC) 8 Hz), 129.14,

132.00 (d, J_PC) 18 Hz) (CH of PPh₂); 132.24 (d, J_PC) 12 Hz,

dCH), 135.16 (d, J_PC) 21 Hz, CH of PPh₂), 137.13 (d, ¹J_PC) 9

Hz), 139.72 (d, J_PC) 9 Hz) (2 × C_ipsoof PPh₂). ³¹P{¹H} NMR

1

(CDCl₃): δ -21.3 (s). IR (Nujol): ν/cm^-11631 (w), 1614 (m),

1585 (w) ν(CdC); 1310 (m), 1246 (m), 1167 (s), 1105 (m), 1037

(m), 1002 (m), 988 (m), 900 (s), 827 (s), 811 (s), 745 (vs), 697

(vs), 624 (m), 573 (m), 508 (m), 476 (s), 454 (s). EI MS [m/z

(relative abundance)]: 397 (27), 396 (M^+•, 100), 395 (18), 394

(7), 331 (22, [M - C₅H₅]⁺), 329 (10), 319 ([M - Ph]⁺, 7), 288

(19), 275 (12), 252 (16), 226 (5), 198 (6), 197 (9), 196 (14), 183

(11), 176 (17), 171 (6), 170 (7), 165 (19), 152 (10), 151 (6), 133

(8), 121 ([C₅H₅Fe]⁺, 28), 120 (7), 56 (Fe, 28). [R]_D) +343 (c )

0.50, CHCl₃). Anal. Calcd for C₂₄H₂₁FeP: C, 72.75; H, 5.34.

Found: C, 72.50; H, 5.37.

¹H NMR (CDCl₃): δ 3.84 (m, 1 H, C₅H₃), 4.06 (s, 5 H, C₅H₅),

3

4.43 (apparent t, 1 H, C₅H₃), 4.88 (m, 1 H, C₅H₃), 6.77 (dd, J_HH

) 16.2, J_PC≈ 1 Hz, CHd), 7.13-7.64 (m, 16 H, Ph, PPh₂and

CHd). ¹³C{¹H} NMR (CDCl₃): δ 67.45 (d, J_PC) 4 H, CH of

C₅H₃), 70.33 (C₅H₅), 70.46 (s, CH of C₅H₃), 72.37 (d, J_PC) 4 H,

CH of C₅H₃), 76.12 (d, ¹J_PC) 9 H, CP of C₅H₃), 88.71 (d, ²J_PC

)

21 H, CCHdCH of C₅H₃), 125.40 (d, ³J_PC) 12 Hz, CHdCHPh),

125.98 (CH of Ph), 126.85 (CH of Ph or PPh₂), 126.97 (d, ⁴J_PC

2 Hz, CHdCHPh), 127.75 (CH of Ph or PPh₂), 128.11 (d, J_PC

)

6 Hz), 128.18 (d, J_PC) 7 Hz) (2 × CH of Ph); 128.54 (CH of Ph),

129.22 (CH of Ph or PPh₂), 132.02 (d, J_PC) 18 Hz), 135.21 (d,

Preparation of (S_p)-2-(Diphenylphosphino)-1-(prop-1-en-1-

yl)ferrocenes ((Z/E)-3). Butyllithium (0.6 mL 2.5 M in hexanes,

1.5 mmol) was added dropwise to a suspension of [PPh₃Et]Br (0.559

g, 1.5 mmol) in dry THF (30 mL) at 0 °C. Nearly all the white

phosphonium salt dissolved to give an orange solution, which was

stirred 0 °C for another 15 min and then treated with a solution of

1 (398 mg, 1.0 mmol) in THF (20 mL). The mixture was stirred

for 30 min at 0 °C and overnight at 60 °C (temperature in bath).

Then, it was quenched by addition of saturated aqueous NaCl

solution and diluted with diethyl ether. The organic layer was

separated, washed with brine, dried (MgSO₄), and evaporated under

vacuum. The orange brown oily residue was purified by column

chromatography on silica gel using hexane-diethyl ether (10:1)

as the eluent. The first orange band was collected and evaporated.

The residue was dissolved in warm heptane (8 mL) and the solution

filtered and crystallized at -18 °C to give rusty brown crystalline

1

J_PC) 21 Hz) (2 × CH of PPh₂); 137.17 (d, J_PC) 9 Hz, C_ipsoof

PPh₂), 137.72 (C_ipsoof Ph), 139.74 (d, ¹J_PC) 10 Hz, C_ipsoof PPh₂).

³¹P{¹H} NMR (CDCl₃): δ -21.7 (s). IR (Nujol) (ν/cm^-1): 1633

(m), 1598 (w), 1584 (m); 1250 (m), 1202 (m), 1164 (s), 1107 (m),

1096 (m), 1070 (m), 1039 (m), 1003 (m), 956 (s), 819 9s), 740

(vs), 694 (vs), 588 (m), 526 (m), 511 (s), 487 (s), 479 (s), 462 (s),

444 (m), 430 (m). MS (EI) [m/z (relative abundance)]: 474 (16),

473 (34), 472 (M^+•), 407 (6), 405 (5), 165 (6), 121 (7, [C₅H₅Fe]⁺).

HR MS (EI): calcd for C₃₀H₂₅⁵⁶FeP, 472.1043; found 472.1051.

Anal. Calcd for C₃₀H₂₅FeP: C, 76.28; H, 5.34. Found: C, 76.17;

H, 5.18.

Preparation of [SP-4-4]-Chloro[2-{(dimethylamino-KN)meth-

yl}phenyl-KC¹][(S_p)-2-(diphenylphosphino-KP)-1-vinylferrocene]-

palladium(II) (6). Bis(µ-chloro)bis{[2-(dimethylamino-κN)phenyl-

κC¹]palladium(II)} (5; 56 mg, 0.1 mmol) and 2 (80 mg, 0.2 mmol),

Inorganic Chemistry, Vol. 45, No. 21, 2006 8795

Sˇteˇpnicˇka and C´ısarˇova´

1

were dissolved in dichloromethane (2 mL). The clear orange

reaction solution was stirred for 1 h at room temperature and then

evaporated under vacuum to give an orange foam, which was

extracted with heptane (25 mL). The extract was filtered while hot,

allowed to cool to room temperature, and then stored at -18 °C

overnight. The separated material was filtered off, washed with

pentane, and dried under vacuum. Yield of 6: 84 mg (62%), orange

powdery solid. Note: the crude product obtained by evaporation

of the reaction mixture is essentially pure but typically contains

traces of the solvent.

125.28 (d, J_PC) 59 Hz, C_ipsoof PPh₂), 126.69 (d, J_PC) 7 Hz,

CH of C₆H₄), 126.90 (CH of C₆H₄), 128.49 (d, J_PC) 11 Hz, CH

of PPh₂), 129.62 (d, J_PC) 11 Hz, CH of PPh₂), 131.38 (d, ¹J_PC

)

49 Hz, C_ipsoof PPh₂), 131.88 (d, J_PC) 2 Hz, CH of PPh₂), 132.21

(d, J_PC) 12 Hz, CH of PPh₂), 132.42 (d, J_PC) 2 Hz, CH of PPh₂),

133.21 (dCH), 135.33 (d, J_PC) 12 Hz, CH of PPh₂), 138.88 (d,

J_PC) 12 Hz, CH of C₆H₄), 148.14 (d, J_PC) 2 Hz, C_ipsoof C₆H₄),

151.53 (d, J_PC≈ 1 Hz, C_ipsoof C₆H₄); the signal due to C-PPh₂at

C₅H₃was not found. ³¹P{¹H} NMR (CDCl₃): δ +30.0 (s). IR

(Nujol) (ν/cm^-1) 1579 (w), 1570 (m), 1229 (m), 1172 (w), ν₃(ClO₄)

1107-1084 (vs, composite); 1000 (m), 940 (m), 844 (s), 746 (s),

698 (m), ν₄(ClO₄) 623 (s); 560 (w), 527 (m), 517 (m), 496 (m),

472 (m), 455 (m). ESI+ MS: m/z 636 ([C₃₃H₃₃⁵⁶Fe¹⁴N³¹P¹⁰⁶Pd]⁺,

the cation; experimental and calculated isotopic patterns agree).

Anal. Calcd for C₃₃H₃₃ClFeNO₄PPd: C, 53.83; H, 4.52; N, 1.90.

Found: C, 53.58; H, 4.58; N, 1.83.

¹H NMR (CDCl₃): δ 2.80 (d, ⁴J_PH) 2.5 Hz, 3 H, NMe₂), 2.84

4

2

4

(d, J_PH) 2.6 Hz, 3 H, NMe₂), 3.94 (dd, J_HH) 13.3, J_PH) 2.7

Hz, 1 H, NCH₂), 4.14 (dd, ²J_HH) 13.3, ⁴J_PH) 2.1 Hz, 1 H, NCH₂),

4.20 (s, 5 H, C₅H₅), 4.51 (br apparent t, 1 H, C₅H₃), 4.79 (dt, J )

2.6, ca. 1.2 Hz, 1 H, C₅H₃), 4.82 (m, 1 H, C₅H₃), 4.89 (dd, ³J_HH

)

2

3

2

10.8, J_HH) 1.7 Hz, 1 H, dCH₂), 5.35 (dd, J_HH) 17.3, J_HH

1.7 Hz, 1 H, dCH₂), 6.30-6.39 (m, 2 H, C₆H₄), 6.60 (dd, ³J_HH

Conversion of 6 to 8. An NMR Study. A solution of silver(I)

perchlorate (6.3 mg, 30 mol) in dry acetonitrile (0.5 mL) was added

to a dichloromethane solution of 6 (17.0 mg, 25 µmol in 1 mL),

causing immediate separation of an off-white precipitate (AgCl).

The mixture was stirred in the dark for 30 min, filtered, and

evaporated. The residue was extracted with dichloromethane (ca.

3 mL), the extract diluted with hexane (ca. 1 mL), and the mixture

filtered to remove silver salts. After evaporation of the filtrate, the

17.3, 10.8 Hz, 1 H, CHd), 6.75-6.96 (m, 2 H, C₆H₄), 7.27-7.85

(m, 10 H, PPh₂). ¹³C{¹H) NMR (CDCl₃): δ 50.03, 50.64 (2 × d,

³J_PC) 2 Hz, NMe₂); 69.22 (d, J_PC) 6 Hz, CH of C₅H₃), 70.19 (d,

1

J_PC) 9 Hz, CH of C₅H₃), 71.40 (C₅H₅), 72.41 (d, J_PC) 49 Hz,

C-P of C₅H₃), 73.42 (d, ³J_PC) 3 Hz, NCH₂), 78.35 (d, J_PC) 15

2

Hz, CH of C₅H₃), 87.76 (d, J_PC) 8 Hz, C-CHdCH₂of C₅H₃),

113.18 (dCH₂), 121.99, 123.45 (2 × CH of C₆H₄); 124.70 (d, J_PC

) 6 Hz, CH of C₆H₄), 127.50 (d, J_PC) 11 Hz, CH of PPh₂), 127.56

(d, J_PC) 13 Hz, CH of PPh₂), 129.96, 130.27 (2 × d, J_PC) 11

residue was dissolved in CDCl₃and analyzed by H, ¹³C, and ³¹P

NMR spectroscopy. The spectra clearly showed an exclusive

formation of 8.

1

Hz, CH of PPh₂); 132.36, 133.72 (2 × d, J_PC) 52 Hz, C_ipsoof

PPh₂); 134.15 (dCH), 134.49, 135.21 (2 × d, J_PC) 12 Hz, CH of

PPh₂); 137.97 (d, J_PC) 11 Hz, CH of C₆H₄), 147.69 (d, J_PC) 2

Hz, C_ipsoof C₆H₄), 152.58 (d, J_PC) 1 Hz, C_ipsoof C₆H₄). ³¹P{¹H)

NMR (CDCl₃): δ +31.4 (s). IR (Nujol) (ν/cm^-1): ν(CdC) 1668

(s); 1579 (w), 1297 (m), 1160 (m), 1098 (m), 1026 (w), 999 (w),

972 (w), 934 (w), 844 (m), 827 (m), 742 (s), 695 (s), 519 (m), 496

Preparation of Tetracarbonyl[(S_p)-2-(diphenylphosphino-KP)-

1-(η²-vinyl)ferrocene]tungsten(0) (9). Toluene (8 mL) was added

to solid [W(cod)(CO)₄] (81 mg, 0.20 mmol) and 2 (80 mg, 0.20

mmol), and the mixture was heated at gentle reflux for 3 h. The

solid educts quickly dissolved to give a clear orange solution. Then,

the reaction solution was cooled to room temperature and filtered

through a short silica gel column (elution with toluene) to remove

decomposition products. The orange eluate was evaporated under

reduced pressure to give an oily residue, which was immediately

extracted with hot heptane. The extract was filtered while hot and

allowed to crystallize at room temperature and then at 0 °C

overnight to yield 9 as orange needles, which were isolated by

suction and dried under vacuum. Yield: 126 mg (91%).

(m), 489 (m), 471 (m). ESI+ MS: m/z 636 ([C₃₃H₃₃⁵⁶Fe¹⁴N³¹P¹⁰⁶

-

Pd]⁺≡ [M - Cl]⁺; experimental isotopic pattern fits the theoretical

one). Anal. Calcd for C₃₃H₃₃ClFeNPPd: C, 58.95; H, 4.95; N, 2.08.

Found: C, 58.76; H, 4.93; N, 1.79.

Preparation of [SP-4-2]-[2-{(Dimethylamino-KN)methyl}-

phenyl-KC¹][(S_p)-2-(diphenylphosphino-KP)-1-(η²-vinyl)ferrocene]-

palladium(II) Perchlorate (8). Bis(acetonitrile)[2-(dimethylamino-

κN)phenyl-κC¹]palladium(II) perchlorate (7; 85 mg, 0.20 mmol)

and 2 (80 mg, 0.2 mmol) were dissolved in chloroform (3 mL).

After being stirring in the dark for 3 h, the reaction solution was

filtered and slowly precipitated with hexane. The mixture was

allowed to stand at 0 °C for 3 h, and the separated solid was filtered

off, washed with diethyl ether, and dried under vacuum. The yield

of 8 is essentially quantitative; however, the product retains the

solvents. An analytical sample of 8 in the form of dark red brown

crystals was obtained by recrystallization from dichoromethane-

diethyl ether.

¹H NMR (CDCl₃): δ 3.21 (ddd, ³J_HH) 13.4, J_PH) 2.1, ²J_HH

≈

0.5 Hz, 1 H, dCH₂), 3.72 (ddd, ³J_HH) 9.0, J_PH) 3.3, ²J_HH≈ 0.5

Hz, 1 H, dCH₂), 3.89 (s, 5 H, C₅H₅), 4.17 (m, 1 H, C₅H₃), 4.52

3

(dt, 1 H, C₅H₃), 4.64 (apparent t, 1 H, C₅H₃), 5.52 (dd, J_HH

)

13.4, 9.0 Hz, 1 H, dCH), 7.02-7.89 (m, 10 H, PPh₂). ¹³C{¹H}

NMR (CDCl₃): δ 64.61 (dCH₂), 67.51 (CH of C₅H₃), 69.12 (d,

J_PC) 11 Hz, CH of C₅H₃), 70.27 (C₅H₅), 74.74 (d, J_PC) 4 Hz,

CH of C₅H₃), 80.69 (d, ¹J_PC) 44 Hz, CP of C₅H₃), 80.96 (dCH),

102.03 (d, ²J_PC) 35 Hz, CCHdCH₂of C₅H₃), 128.16 (d, J_PC) 9

Hz), 128.41 (d, J_PC) 10 Hz), 128.81 (d, J_PC) 2 Hz), 129.81 (d,

J_PC) 11 Hz), 130.87 (d, J_PC) 2 Hz), 134.26 (d, J_PC) 13 Hz) (6

¹H NMR (CDCl₃): δ 2.70 (d, ⁴J_PH) 2.2 Hz, 3 H, NMe₂), 3.13

4

2

4

1

(d, J_PH) 3.7 Hz, 3 H, NMe₂), 3.79 (dd, J_HH) 13.7, J_PH) 3.9

Hz, 1 H, NCH₂), 3.98 (apparent qi, J ≈ 1.4 Hz, 1 H, C₅H₃), 4.31

(s, 5 H, C₅H₅), 4.71 (td, J ) 2.6, 0.6 Hz, 1 H, C₅H₃), 4.74 (br d,

× CH of PPh₂); 135.04 (d, J_PC) 48 Hz), 140.62 (d, J_PC) 43

2

Hz) (2 × C_ipsoof PPh₂); 199.62 (d, J_PC) 7 Hz), 203.57 (d, J_PC

2

) 32 Hz), 206.45 (d, J_PC) 8 Hz), 210.27 (d, J_PC) 5 Hz) (Ct

O). ³¹P{¹H} NMR (CDCl₃): δ +23.7 (s with ¹⁸³W satellites, ¹J_WP

) 249 Hz). IR (Nujol): (ν/cm^-1): ν(CtO) 2022 (vs), 1915-1930

(vs composite), 1874 (vs); 1308 (w), 1217 (m), 1183 (w), 1164

(w), 1096 (m), 1033 (m), 1000 (m), 917 (m), 857 (w), 830 (m),

815 (w), 747 (s), 692 (s), 602 (s), 570 (s), 512 (s), 502 (w), 484

(s), 763 (m), 438 (m). MS (EI): m/z (relative abundance) 682 (38,

M^+•), 664 (7, [M - CO]⁺), 636 (1, [M - 2CO]⁺), 608 (21, [M -

3CO]⁺), 580 (65, [M - 4CO]⁺), 502 (33), 500 (33), 474 (7), 445

(8), 424 (15), 396 (100, 1^+.), 369 (12), 331 (19), 288 (13), 275 (9),

²J_HH≈ 13.4 Hz, 1 H, NCH₂), 5.12 (br d, J_HH) 16.5 Hz, 1 H,

3

dCH₂), 5.12 (dt, J ) 2.4, 1.2 Hz, 1 H, C₅H₃), 5.28 (br dd, ³J_HH

)

9.6, J ≈ 1.3 Hz, 1 H, dCH₂), 6.73-7.23 (m, 4 H, C₆H₄), 7.33 (dd,

³J_HH) 16.5, 9.6 Hz, 1 H, CHd), 7.40-7.69 (m, 10 H, PPh₂). ¹³C-

3

{¹H} NMR (CDCl₃): δ 49.91 (d, J_PC) 2 Hz, NMe₂), 52.58 (d,

³J_PC≈ 2 Hz, NMe₂), 71.05 (CH of C₅H₃; δ_H3.98), 71.80 (C₅H₅),

73.00 (d, J_PC) 3 Hz, CH of C₅H₃; δ_H5.12), ca. 73.0 (br, NCH₂),

2

75.58 (d, J_PC) 7 Hz, CH of C₅H₃; δ_H4.71), 90.25 (d, J_PC) 21

Hz, C-CHdCH₂of C₅H₃), 100.93 (dCH₂), 124.11 (CH of C₆H₄),

8796 Inorganic Chemistry, Vol. 45, No. 21, 2006

Ferrocene Alkenylphosphines

252 (10), 196 (7), 133 (9), 121 (24, [C₅H₅Fe]⁺), 108 (7), 78 (17),

56 (27, Fe⁺). HR MS (EI): calcd for C₂₈H₂₁⁵⁶FeO₄P¹⁸⁴W, 692.0036;

found 692.0057. [R]_D) -302 (c ) 0.51, CHCl₃). Anal. Calcd for

C₂₈H₂₁FeO₄PW: C, 48.59; H, 3.06. Found: C, 48.55; H, 3.08.

Synthesis of Tungsten Carbonyl Complexes with (Z/E)-3. The

reaction was performed similarly to the preparation of 9. [W(cod)-

(CO)₄] (82 mg, 0.20 mmol) and (Z/E)-3 (84 mg, 0.20 mmol) in

toluene (8 mL) were heated at reflux for 3 h. The reaction solution

was filtered trough a short silica gel column, eluting with toluene.

The yellow eluate was evaporated to give the crude product as an

orange gummy residue with the characteristic smell of the liberated

cyclooctadiene. This material was purified by column chromatog-

raphy (silica gel, 10:1 hexane-diethyl ether). The first yellow band

containing mostly impurities was discarded (ca. 15 mg). The second,

major yellow band was evaporated to give and yellow-orange foam

(ca. 120 mg), which was dissolved in boiling heptane (5 mL). The

solution was treated with a little charcoal and filtered while hot

and allowed to crystallize at 0 °C. The separated crystalline product

was washed with pentane and dried under vacuum. Yield: 62 mg

(44%), rusty brown crystalline solid. The product is a mixture of

(Z)-10 and (E)-10 isomers in ca. 5:1 ratio.

yellow fraction gave compound (E)-12 as a bright orange amor-

phous solid (ca. 35 mg, 23%). Note: the product distribution can

be shifted in favor of the chelate complex by increasing the reaction

temperature and time. For instance, heating the same educt mixture

at reflux temperature for 3 h gave a mixture containing (E)-12 (ca.

90%) and (E)-11 (ca. 10%). Chromatographic purification of the

product mixture was rather tedious due to similar retention

characteristics of its components.

Analytical Data for Pentacarbonyl[(E,S_p)-2-(diphenylphos-

phino-κP)-1-(2-phenylethen-1-yl)ferrocene]tungsten(0) ((E)-11).

¹H NMR (CDCl₃): δ 4.28 (s, 5 H, C₅H₅), 4.41 (m, 1 H, C₅H₃),

4.66 (m, 1 H, C₅H₃), 4.98 (m, 1 H, C₅H₃), 6.30 and 6.61 (2 × d,

³J_HH) 16.0 Hz, CHdCH), 6.99-7.81 (m, 15 H, Ph and PPh₂).

¹³C{¹H} NMR (CDCl₃): δ 69.42 (d, J_PC) 4 Hz), 70.48 (d, J_PC

)

1

9 Hz) (2 × CH of C₅H₃); 71.12 (C₅H₅), 77.59 (d, J_PC) 40 Hz,

2

CP of C₅H₃), 77.79 (d, J_PC) 18 Hz, CH of C₅H₃), 86.77 (d, J_PC

) 4 Hz, CCHdCH of C₅H₃), 124.74 (d, J_PC≈ 1 Hz, CHdCHPh;

correlation with δ_H6.30), 125.94, 127.13 (2 × CH of Ph); 128.17

(d, J_PC) 10 Hz, CH of PPh₂), 128.32 (CHdCHPh; correlation

with δ_H6.61), 128.36 (d, J_PC) 10 Hz, CH of PPh₂), 128.50 (CH

of Ph), 129.76 (d, J_PC) 2 Hz), 130.36 (d, J_PC) 2 Hz), 132.08 (d,

J_PC) 12 Hz), 133.27 (d, J_PC) 12 Hz) (4 × CH of PPh₂); 135.82

MS (EI): m/z (relative abundance) 706 (23, M^+•), 678 (10, [M

- CO]⁺), 650 (3, [M - 2CO]⁺), 622 (15, [M - 3CO]⁺), 594 (37,

[M - 4CO]⁺), 514 (13), 438 (15), 490 (11), 410 (100, 3^+•), 395

(19, [3 - Me]⁺), 183 (14), 121 (30, [C₅H₅Fe]⁺). HR MS (EI): calcd

for C₂₉H₂₃⁵⁶FeO₄P¹⁸⁴W, 706.0193; found 706.0210.

1

(d, J_PC) 41 Hz), 136.51 (d, J_PC) 43 Hz) (2 × C_ipsoof PPh₂);

137.13 (C_ipsoof Ph), 197.73 (d, J_PC) 7 Hz, ¹⁸³W satellites, J_WC

2

1

) 126 Hz, CtO cis-P), 198.97 (d, J_PC) 22 Hz, ¹⁸³W satellites

2

not detected, CtO trans-P). ³¹P{¹H} NMR (CDCl₃): δ +11.1 (s

with ¹⁸³W satellites, J_WP) 246 Hz). IR (Nujol) (ν/cm^-1): ν(Ct

1

NMR Data for Tetracarbonyl[(Z,S_p)-2-(diphenylphosphino-

1

O) 2069 (vs), 1989 (m), ca. 1880-1955 (vs, br composite); 1311

(w), 1248 (w), 1159 (m), 1149 (m), 1108 (m), 1093 (m), 1000 (m),

984 (w), 957 (m), 824 (m), 762 (m), 751 (s), 745 (s), 707 (m), 696

(s), 598 (vs), 579 (vs), 562 (m), 510 (m), 485 (s), 466 (s), 452 (m).

HR MS (FAB): calcd for C₃₅H₂₆⁵⁶FeO₅P¹⁸⁴W ([M + H]⁺),

797.0377; found 768.0352. Anal. Calcd for C₃₅H₂₅FeO₅PW: C,

52.79; H, 3.16. Found: C, 52.57; H, 3.14.

κP)-1-(η(1,2)-prop-1-en-1-yl)ferrocene ]tungsten(0), (Z)-10. H

3

NMR (CDCl₃): δ 1.71 (dd, J_HH) 6.2, J_PH) 1.0 Hz, 3 H, Me),

3.87 (s, 5 H, C₅H₅), 4.36 (dt, 1 H, C₅H₃), 4.43 (dt, 1 H, C₅H₃),

3

4.73 (t, 1 H, C₅H₃), 4.90 (ddq, J_HH) 9.4 Hz, J_PH≈ 0.5, J_HH

)

≈

3

6.2 Hz, 1 H, CHdCHMe), 5.77 (br “dd”, J_HH) 9.4 Hz, J_PH

1.0 Hz, 1 H, CHdCHMe), 7.10-7.92 (m, 10 H, PPh₂). ¹³C{¹H}

NMR (CDCl₃): δ 16.90 (Me), 68.75, 68.99 (d, J_PC) 12 Hz) (2 ×

CH of C₅H₃); 70.41 (C₅H₅), 75.29 (d, J_PC) 4 Hz, CH of C₅H₃),

Analytical Data for Tetracarbonyl[(E,S_p)-2-(diphenylphos-

phino-κP)-1-(η(1,2)-2-phenylethen-1-yl)ferrocene]tungsten(0) ((E)-

1

84.58 (CHdCHMe), 86.94 (d, J_PC) 43 Hz, CP of C₅H₃), 89.49

(CHdCHMe), 97.17 (d, ²J_PC) 37 Hz, CCHdCH of C₅H₃), 128.08

(d, J_PC) 10 Hz), 128.40 (d, J_PC) 10 Hz), 128.71 (d, J_PC) 2 Hz),

1

12). H NMR (CDCl₃): δ 3.93 (s, 5 H, C₅H₅), 4.23 (br s, 1 H,

C₅H₃), 4.52 (m, 1 H, C₅H₃), 4.66 (m, 1 H, C₅H₃), 4.79 (dd, ³J_HH

)

13.1, ⁴J_PH) 1.2 Hz, 1 H, CHdCHPh), 5.89 (dd, ³J_HH) 13.1, ⁵J_PH

) 0.9 Hz, 1 H, CHdCHPh), 7.06-7.85 (m 15 H, Ph and PPh₂).

¹³C{¹H} NMR (CDCl₃): δ 67.54, 69.39 (d, J_PC) 12 Hz) (2 × CH

of C₅H₃); 70.32 (C₅H₅), 74.91 (d, J_PC) 4 Hz, CH of C₅H₃), 75.38

130.27 (d, J_PC) 11 Hz), 130.63 (d, J_PC) 2 Hz), 134.04 (d, J_PC

)

1

13 Hz) (6 × CH of PPh₂); 136.64 (d, J_PC) 47 Hz), 139.80 (d,

¹J_PC) 44 Hz) (2 × C_ipsoof PPh₂); 201.12 (d, ¹J_PC) 7 Hz), 204.83

1

(d, J_PC) 29 Hz), 205.63 (d, J_PC) 8 Hz), 209.83 (d, J_PC) 5

Hz) (4 × CtO). ³¹P{¹H} NMR (CDCl₃): δ +24.9 (s with ¹⁸³W

1

(CHdCHPh), 80.20 (d, J_PC) 44 Hz, CP of C₅H₃), 86.53 (CHd

1

2

satellites, J_WP) 249 Hz).

CHPh), 103.15 (d, J_PC) 38 Hz, CCHdCH of C₅H₃), 125.10,

127.01 (2 × CH of Ph); 128.30 (d, J_PC) 9 Hz, CH of PPh₂), 128.37

NMR Data for Tetracarbonyl[(E,S_p)-2-(diphenylphosphino-

κP)-1-(η(1,2)-prop-1-en-1-yl)ferrocene ]tungsten(0), (E)-10. ³¹P-

{¹H} NMR (CDCl₃): δ +24.4 (s, ¹⁸³W satellites not read).

Preparation of Tungsten Carbonyl Complexes with (E)-4.

[W(cod)(CO)₄] (82 mg, 0.20 mmol) and (E)-4 (95 mg, 0.20 mmol)

in toluene (8 mL) were heated at 100 °C (temperature in the bath)

in the dark for 2 h. The reaction mixture was cooled to room

temperature and filtered through a short silica gel column (elution

with toluene). The orange eluate was evaporated under reduced

pressure to give an orange-red oil (ca. 124 mg, smell of the liberated

cyclooctadiene was clearly detectable), which was subsequently

purified by column chromatography on silica gel. Eluting with 10:1

hexane-diethyl ether gave three fractions, followed by a small band

due to a brown material (probably decomposition products). The

first, very minor, yellow band was discarded. The second yellow

band was evaporated to give an orange glassy solid (65 mg) whose

subsequent crystallization from heptane (3 mL) afforded analytically

pure (E)-11 as well-developed, dark ruby red crystals, which were

isolated by suction (46 mg, 28%). Finally, evaporation of the third

(CH of Ph), 128.42 (d, J_PC) 12 Hz), 128.92 (d, J_PC) 1 Hz),

129.89 (d, J_PC) 11 Hz), 130.90 (d, J_PC) 2 Hz), 134.18 (d, J_PC

)

1

13 Hz) (5 × CH of PPh₂); 134.98 (d, J_PC) 48 Hz), 140.70 (d,

¹J_PC) 43 Hz) (2 × C_ipsoof PPh₂); 141.19 (C_ipsoof Ph), 201.79 (d,

²J_PC) 5 Hz, ¹⁸³W satellites, ¹J_WC) 124 Hz), 203.14 (d, ²J_PC) 33

Hz, ¹⁸³W satellites, ¹J_WC) 154 Hz), 206.51 (d, ²J_PC) 8 Hz, ¹⁸³

W

satellites, ¹J_WC) 123 Hz), 212.47 (d, ²J_PC) 5 Hz, ¹⁸³W satellites,

¹J_WC) 151 Hz) (4 × CtO). ³¹P{¹H} NMR (CDCl₃): δ +24.9 (s

1

with ¹⁸³W satellites, J_WP) 293 Hz). IR (Nujol) (ν/cm^-1): ν(Ct

O) 2022 (vs), 1870-1945 (vs, br composite); 1306 (w), 1253 (m),

1215 (m), 1158 (m), 1098 (s), 1076 (m), 1027 (m), 1001 (m), 826

(s), 749 (s), 739 (s), 693 (vs), 601 (s), 576 (s), 520 (vs), 506 (m),

484 (s), 462 (s). MS (EI): m/z (relative abundance) 768 (3, M^+•),

740 (2, [M - CO]⁺), 712 (5, [M - 2CO]⁺), 686 (3, [M - 3CO]⁺),

658 (3, [M - 4CO]⁺), 576 (3), 438 (15), 472 (100, 4^+•). HR MS

(EI): calcd for C₃₄H₂₅⁵⁶FeO₄P¹⁸⁴W, 768.0349; found, 768.0355.

X-ray Crystallography. Single crystals suitable for X-ray dif-

fraction analysis were selected from the reaction batch (1, red prism,

Inorganic Chemistry, Vol. 45, No. 21, 2006 8797

Sˇteˇpnicˇka and C´ısarˇova´

Table 5. Crystallographic Data and Data Collection and Structure Refinement Parameters for 1, 2, 8, 9, and (E)-11

param

formula

M_r(g mol^-1

1

2

8

9

(E)-11

C₂₃H₁₉FeOP

398.20

C₂₄H₂₁FeP

396.23

C₃₃H₃₃ClFeNO₄PPd

736.27

C₂₈H₂₁FeO₄PW

652.12

C₃₅H₂₅FeO₅PW

796.22

)

cryst system

space group

a (Å)

b (Å)

c (Å)

monoclinic

P2₁(No. 4)

8.4927(1)

17.2736(2)

13.0060(1)

103.6854(6)

1853.81(3)

4

orthorhombic

P2₁2₁2₁(No. 19)

10.5452(2)

12.9788(2)

13.8939(2)

monoclinic

P2₁(No. 4)

9.0782(2)

14.3355(2)

12.4391(2)

105.508(1)

1559.89(5)

2

orthorhombic

P2₁2₁2₁(No. 19)

10.0170(1)

11.4879(2)

21.2688(4)

orthorhombic

P2₁2₁2₁(No. 19)

12.915(1)

13.742(2)

34.841(1)

â (deg)

V (Å³)

Z

1901.58(5)

4

1.384

2447.49(7)

4

1.878

6184(1)

8

1.711

D (g mL^-1

)

1.427

0.908

1.568

1.216

µ(Mo KR) (mm^-1

)

0.881

5.388

4.280

T^a

0.710-0.886

0.705-0.939

0.495-0.755

34 771^e

5595/5318

5.45

0.349-0.555

83 405^g

12 848/10 627

4.13

f

reflcn tot.

54 311^e

30 254^e

4345/4192

3.80

27 206^e

unique/obsd^breflcns

8482/8257

3.58

7035/6630

3.64

R

_int(%)^c

no. of params

434

2.43

2.56, 5.94

-0.019(7)

0.52, -0.41

604808

235

2.22

2.38, 5.32

0.00(1)

0.23, -0.25

604809

393

2.65

3.05, 5.76

-0.03(1)

0.56, -0.49

604810

328

2.27

2.58, 4.95

-0.019(6)

1.09, -1.05

604811

707

2.65

3.99, 4.76

-0.022(4)

1.18, -0.64

604812

R (obsd reflcns) (%)^d

R, wR (all data) (%)^d

Flack’s param

∆F (e Å^-3

)

CCDC deposition no.

c

2

^aThe range of transmission coefficients. ^bReflections with I_o> 2σ(I_o). R_int) ∑|F_o- F_o(mean)|/∑F_o, where F_o(mean) is the average intensity for

symmetry-equivalent diffractions. ^dR ) ∑||F_o| - |F_c||/∑|F_o|, wR ) [∑{w(F_o- F_c)²}/∑w(F_o)²]^1/2

.

^e2θ e 55°. ^fNot corrected. ^g2θ e 53°.

2

0.20 × 0.30 × 0.50 mm³) or were grown by crystallization from

hot heptane (2, red-brown prism, 0.20 × 0.25 × 0.38 mm³;

9, orange bar, 0.06 × 0.13 × 0.30 mm³; (E)-11, deep red frag-

ment, 0.06 × 0.13 × 0.23 mm³) or from dichloromethane-diethyl

ether (8, rusty brown plate; 0.05 × 0.15 × 0.38 mm³). Full-set

diffraction data ((h(k(l) were collected on Nonius KappaCCD

(1, 2, 8, 9) and Oxford KM4 CCD ((E)-11) diffractometers

equipped with Cryostream Cooler (Oxford Cryosystems) and

Oxford Cryojet (Oxford Instruments), respectively, at 150(2) K

using graphite-monochromatized Mo KR radiation (λ ) 0.710 73

Å). The data for 8, 9, and (E)-11 were corrected for absorption

(8 and 9, a Gaussian method based on the indexed crystal shape;

(E)-11, an analytical method). Relevant crystallographic data are

given in Table 5.

The structures were solved by direct methods (SIR97⁵⁴) and

refined by weighted full-matrix least squares on F²(SHELXL97⁵⁵).

Final geometric calculations were carried out with a recent version

of Platon program.⁵⁶All non-hydrogen atoms were freely refined

with anisotropic thermal motion parameters. Hydrogen atoms were

included in the calculated positions and refined using the “riding”

model.

Crystallographic data for all structures excluding the structure

factors have been deposited with the Cambridge Crystallographic

Data Centre (see the Supporting Information paragraph).

Acknowledgment. Financial support for this study was

provided by the Czech Science Foundation (Grant No. GA

CR 203/05/0276). We thank Professor Jiˇr´ı Ludv´ık for

providing access to the electrochemical apparatus and Helena

Dlouha´ for recording CD spectra.

Supporting Information Available: Complete crystallographic

data (excluding the structure factors) as CIF files and alternative

views of (Z/E)-10 (Figures S1 and S2). This material is available

free of charge via the Internet at http://pubs.acs.org. Alternatively,

the crystallographic data can be obtained via www.ccdc.cam.ac.uk/

conts/retrieving.html or from the Cambridge Crystallographic Data

Center, 12 Union Road, Cambridge CB21EZ, U.K. (fax, +44 1223-

336-033; e-mail, deposit@ccdc.cam.ac.uk). The deposition numbers

are given in Table 5.

IC061278G

(55) Sheldrick, G. M. SHELXL97. Program for Crystal Structure Refine-

ment from Diffraction Data; University of Go¨ttingen: Go¨ttingen,

Germany, 1997.

(56) Spek, A. L. Platon-A multipurpose crystallographic tool. Available

via the Internet at http://www.cryst.chem.uu.nl/platon/.

(54) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G. L.; Giaco-

vazzo, C.; Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.; Spagna,

R. J. Appl. Crystallogr. 1999, 32, 115-119.

8798 Inorganic Chemistry, Vol. 45, No. 21, 2006

Article Doi

Synthesis and coordination behavior of planar-chiral ferrocene alkenylphosphines

DOI: 10.1021/ic061278g

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Article abstract of DOI:10.1021/ic061278g

Full text of DOI:10.1021/ic061278g

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