Alkynyldiphenylphosphine d8 (Pt, Rh, Ir) complexes: Contrasting behavior toward cis-[Pt(C6F5)2(THF) 2]

Inorg. Chem. 2004, 43, 8185−8198

Alkynyldiphenylphosphine d⁸(Pt, Rh, Ir) Complexes: Contrasting

Behavior toward cis-[Pt(C₆F₅)₂(THF)₂]

Jesu´s R. Berenguer,^†Mar´ıa Bernechea,^†Juan Fornie´s,*^,‡Ana Garc´ıa,^†Elena Lalinde,*^,†and

M. Teresa Moreno^†

Departamento de Qu´ımica-Grupo de S´ıntesis Qu´ımica de La Rioja, UA-CSIC, UniVersidad de La

Rioja, 26006, Logron˜o, Spain, and Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de

Materiales de Arago´n, UniVersidad de Zaragoza-Consejo Superior de InVestigaciones Cient´ıficas,

50009 Zaragoza, Spain

Received July 27, 2004

The synthesis and characterization of a series of mononuclear d⁸complexes with at least two P-coordinated

alkynylphosphine ligands and their reactivity toward cis-[Pt(C₆F₅)₂(THF)₂] are reported. The cationic [Pt(C₆F₅)-

(PPh₂CtCPh)₃](CF₃SO₃), 1, [M(COD)(PPh₂CtCPh)₂](ClO₄) (M ) Rh, 2, and Ir, 3), and neutral [Pt(o-C₆H₄E₂)-

(PPh₂C

t

CPh)₂] (E O, 6, and S, 7) complexes have been prepared, and the crystal structures of 1, 2, and

)

7

‚

CH₃COCH₃have been determined by X-ray crystallography. The course of the reactions of the mononuclear

complexes 1 3, 6, and 7 with cis-[Pt(C₆F₅)₂(THF)₂] is strongly influenced by the metal and the ligands. Thus,

treatment of 1 with 1 equiv of cis-[Pt(C₆F₅)₂(THF)₂] gives the double inserted cationic product [Pt(C₆F₅)(S) C-

(Ph) C(PPh₂)C(PPh₂)dC(Ph)(C₆F₅) Pt(C₆F₅)(PPh₂C CPh)](CF₃SO₃) (S THF, H₂O), 8 (S H₂O, X-ray), which

evolves in solution to the mononuclear complex [(C₆F₅)(PPh₂C CPh)Pt C₁₀H₄-1-C₆F₅-4-Ph-2,3- PP (PPh₂)₂](CF₃

−

µ-{

d

}

t

)

t

{

κ

′

}

SO₃), 9 (X-ray), containing a 1-pentafluorophenyl-2,3-bis(diphenylphosphine)-4-phenylnaphthalene ligand, formed

by annulation of a phenyl group and loss of the Pt(C₆F₅) unit. However, analogous reactions using 2 or 3 as

precursors afford mixtures of complexes, from which we have characterized by X-ray crystallography the

alkynylphosphine oxide compound [(C₆F₅)₂Pt(

(3). Complexes 6 and 7, which contain additional potential bridging donor atoms (O, S), react with cis-[Pt(C₆F₅)₂-

(THF)₂] in the appropriate molar ratio (1:1 or 1:2) to give homo- bi- or trinuclear [Pt(PPh₂C CPh)( E-o-C₆H₄E₂)-

P: CPh)Pt(C₆F₅)₂] (E O, 11, and S, 12) and Pt( -o-C₆H₄E₂)( P:

²-PPh₂C ₃κ²EE ²-PPh₂C

CPh)₂}{Pt(C₆F₅)_{2 2}] (E O, 13, and S, 14) complexes. The molecular structure of 14 has been confirmed by

X-ray diffraction, and the cyclic voltammetric behavior of precursor complexes 6 and 7 and polymetallic derivatives

11 14 has been examined.

µ-κO:η tCPh)]₂, 10, in the reaction with the iridium complex

²-PPh₂(O)C

t

µ-κ

(

µ

-

κ

η

t

)

[{

µ

-

′

µ

-

κ

η

t

}

)

−

Introduction

P-C(alkyne) bond cleavage processes, generating acetylide

(CtC) and phosphide (PPh₂) fragments,^16-21which are

frequently involved in subsequent coupling or insertion

reactions,^22-26(iii) the possibility of a variety of interesting

ligand-based couplings^27,28and insertion reactions,^29-36and

(iv) the possible activation of the uncoordinated alkynyl

function upon simple P-coordination toward nucleophilic or

electrophilic attacks.^28,37-39

This work is part of our systematic investigation into

alkynylphosphine-transition metal complexes. Alkynylphos-

phines PPh₂CtCR are polyfunctional ligands which show

versatile behavior in coordination chemistry. Their interest

is due to different factors including (i) the ability of

alkynylphosphine ligands to adopt various coordination

modes,^1-15(ii) the facility with which these ligands undergo

* Authors to whom correspondence should be addressed. E-mail:

elena.lalinde@dq.unirioja.es (E.L.), forniesj@posta.unizar.es (J.F.).

^†Universidad de La Rioja, UA-CSIC.

(3) Louattani, E.; Suades, J. J. Organomet. Chem. 2000, 604, 234.

(4) Bardaj´ı, M.; Laguna, A.; Jones, P. G. Organometallics 2001, 20, 3906.

(5) Louattani, E.; Suades, J. Inorg. Chim. Acta 1999, 291, 207.

(6) Lucas, N. T.; Cifuentes, M. P.; Nguyen, L. T.; Humphrey, M. G. J.

Cluster Sci. 2001, 12, 201.

^‡Universidad de Zaragoza-CSIC.

(1) Went, M. J. Polyhedron 1995, 14, 465.

(2) Baumgartner, T.; Huynh, K.; Schleidt, S.; Lough, A. J.; Manners, I.

Chem.sEur. J. 2002, 8, 4622.

(7) Patel, H. A.; Carty, A. J.; Hota, N. K. J. Organomet. Chem. 1973, 50,

247.

10.1021/ic048987j CCC: $27.50

Published on Web 11/13/2004

Inorganic Chemistry, Vol. 43, No. 25, 2004 8185

Berenguer et al.

Several years ago, Carty and co-workers showed that

diphenyl(phenylethynyl)phosphine complexes cis-[MX(Y)-

(PPh₂CtCPh)₂] [X ) Y ) Cl, I, CF₃, C₆F₅; X(Y) )

o-C₆H₄O₂, Me(Cl)] suffer intramolecular coupling of the

alkynylphosphine ligands on heating to form the bis-

(diphenylphosphino)naphthalene complexes cis-[PtX(Y)-

{o-C₁₆H₁₀(PPh₂)₂}].^27,28With the aim of investigating the

possibility of inducing the alkyne coupling of two P-

coordinated PPh₂CtCR ligands by η²-coordination to a

second metal center, we decided to examine the reactivity

of cis-[MX₂(PPh₂CtCR)₂] (M ) Pt, Pd; X ) Cl, CtCR′,

C₆F₅) toward the platinum or palladium species cis-[M(C₆F₅)₂-

(THF)₂] (M ) Pt, Pd; THF ) tetrahydrofuran). These

reactions strongly depend on the nature of the X and R

groups. Thus, when X is a group which has a tendency to

form bridges between metal centers, it competes with the

η²-bonding capability of the PPh₂CtCR groups to coordinate

the “cis-M(C₆F₅)₂” fragments.^40,41However, when X is a

group with low tendency to form bridges, we have found an

unusual reactivity pattern. Thus, cis-[M(C₆F₅)₂(PPh₂CtCR)₂]

(M ) Pt, Pd; R ) Ph, Tol) react with cis-[Pt(C₆F₅)₂(THF)₂]

to give unusual µ-2,3-bis(diphenylphosphino)-1,3-butadien-

1-yl binuclear complexes {µ-C(R)dC(PPh₂)C(PPh₂)dC(R)-

C₆F₅} formed from initial bis(η²-alkyne) adducts (µ-κP:η²-

PPh₂CtCR)₂(detected at low temperature) through an

unexpectedly easy sequential insertion of both PPh₂CtCR

into a robust Pt-C₆F₅bond.^42,43The overall process is regio-

and stereoselective leading, in the case of cis-[Pt(C₆F₅)₂-

(PPh₂CtCR)(PPh₂CtCtBu)], to a very crowded butadienyl

C(tBu)dC(PPh₂)C(PPh₂)dC(C₆F₅)R backbone, which sta-

bilizes an unprecedented, T-shaped, unsaturated three-

coordinated platinum center in solid state (R ) Tol). In this

context and to study the different factors (metal, charge,

and coligands) that influence the course of this insertion

process, we considered it of interest to prepare novel d⁸

cationic or neutral complexes stabilized by at least two

P-coordinated PPh₂CtCPh ligands and to study their reac-

tivity toward cis-[Pt(C₆F₅)₂(THF)₂]. In this paper we report

the synthesis of novel cationic [Pt(C₆F₅)(PPh₂CtCPh)₃](CF₃-

SO₃) and [M(COD)(PPh₂CtCPh)₂](ClO₄) (M ) Rh, Ir) and

neutral [Pt(o-C₆H₄S₂)(PPh₂CtCPh)₂] derivatives and the

results of their reactions and those of the analogous catecho-

late complex [Pt(o-C₆H₄O₂)(PPh₂CtCPh)₂],²⁸6, with cis-

[Pt(C₆F₅)₂(THF)₂].

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1979, 750.

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Experimental Section

General Considerations. All reactions and manipulations were

carried out under nitrogen atmosphere using Schlenk techniques

and distilled solvents purified by known procedures. IR spectra were

recorded on a Perkin-Elmer FT-IR 1000 spectrometer as Nujol mulls

between polyethylene sheets. NMR spectra were recorded on a

Bruker ARX 300 spectrometer; chemical shifts are reported in ppm

relative to external standards (SiMe₄, CFCl₃, and 85% H₃PO₄), and

coupling constants, in Hz. Elemental analyses were carried out with

a Perkin-Elmer 2400 CHNS/O microanalyzer, and the electrospray

mass spectra, on a HP5989B with interphase API-ES HP 59987A.

Conductivities were measured in acetone solutions (ca. 5 × 10^-4

mol L^-1) using a Crison GLP31 conductimeter. Cyclic voltammetric

studies were performed using an EG&G-283 potenciostat/gal-

vanostat. A standard three-electrode configuration was used, with

platinum working and platinum auxiliary electrodes and a saturated

calomel electrode (SCE reference). All potentials are quoted vs the

ferrocene/ferrocenium couple (Fc/Fc⁺) (used as an internal refer-

ence). Anhydrous CH₂Cl₂was used as solvent under a nitrogen

atmosphere, and 0.1 M (NBu₄)(PF₆) was used as supporting

electrolyte. PPh₂CtCPh,⁴⁴[Pt(µ-Cl)(C₆F₅)(tht)]₂,⁴⁵[M(µ-Cl)-

(20) Cherkas, A. A.; Randall, L. H.; MacLaughlin, S. A.; Mott, G. N.;

Taylor, N. J.; Carty, A. J. Organometallics 1988, 7, 969.

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101, 5422.

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P. J. Am. Chem. Soc. 1998, 120, 3504.

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Organometallics 2000, 19, 54.

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Organometallics 2000, 19, 1522.

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C. Organometallics 2001, 20, 2864.

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8186 Inorganic Chemistry, Vol. 43, No. 25, 2004

Alkynyldiphenylphosphine d⁸(Pt, Rh, Ir) Complexes

(COD)]₂(M ) Rh,⁴⁶Ir⁴⁷), cis-[PtCl₂(DMSO)₂],⁴⁸cis-[Pt(C₆F₅)₂-

(THF)₂],⁴⁹and PPh₂(O)CtCPh⁵⁰were prepared according to

literature methods.

Safety Note. Perchlorate salts with organic ligands are poten-

tially explosiVe. Only small amounts of material should be prepared,

and these should be handled with great caution.

COD], 80.8 [AMXX′, ¹J(C-P) + ³J(C-P) ) 95.9 Hz, ²J(C_R-Rh)

∼ 1 Hz, C_R], 30.7 (s CH₂<, COD).

Synthesis of [Ir(COD)(PPh₂C≡CPh)₂](ClO₄), 3. A suspension

of [Ir(µ-Cl)(COD)]₂(0.100 g, 0.149 mmol) in acetone (20 mL) was

treated with NaClO₄(0.837 g, 5.96 mmol) and PPh₂CtCPh (0.171

g, 0.556 mmol) (molar ratio 1:40:4). The color of the resulting

suspension changed from orange to red, and the mixture was stirred

for 1 h. The solvent was evaporated and the residue treated with

CH₂Cl₂(40 mL). After filtration through Kieselguhr, the filtrate

was evaporated to dryness and the residue treated with diethyl ether

(10 mL) affording a pink solid (3) (0.263 g, 91% yield). Anal. Calcd

for C₄₈ClH₄₂O₄P₂Ir (M_r) 972.48): C, 59.28; H, 4.35. Found: C,

59.17; H, 4.52. Λ_M: 122 Ω^-1‚cm²‚mol^-1. MS ES (+): m/z 873

([M - ClO₄]⁺, 100%). IR (cm^-1): ν(CtC) 2175 s; ν(ClO₄^-) 1094

vs, 623 m. ¹H NMR (CDCl₃, 20 °C, δ): 7.63 (m, 8H), 7.40 (m, 12

H), 7.22 (m, 6H), 7.03 (m, 4H) Ph, 4.50 (s, br, 4H, CHd, COD),

2.38 (m, br, 4H, CH₂<, COD), 2.22 (m, br, 4H, CH₂<, COD).

³¹P{¹H} NMR (CDCl₃, 20 °C, δ): -0.41 (s). ¹³C{¹H} NMR (CDCl₃,

20 °C, δ): 133.6 [“t”, ²J(C-P) + ⁴J(C-P) ) 12.6 Hz; C_o, PPh₂],

132.1 (s, br, C_o, ≡CPh), 131.9 (s, C_p, PPh₂), 130.6 (s, C_p, ≡CPh),

Synthesis of [Pt(C₆F₅)(PPh₂C≡CPh)₃](CF₃SO₃), 1. A yellow

solution of [Pt(µ-Cl)(C₆F₅)(tht)]₂(0.120 g, 0.123 mmol) in acetone

(40 mL) was treated with AgCF₃SO₃(0.0635 g, 0.247 mmol) and

the mixture stirred for 1 h at room temperature and then filtered

through Kieselgurh. To the resulting yellow solution was added

PPh₂CtCPh (0.212 g, 0.741 mmol), and the mixture was stirred

for 1 h. Evaporation to dryness and treatment with EtOH (5 mL)

afforded 1 as a white solid (0.223 g, 66% yield). Anal. Calcd for

C₆₇F₈H₄₅O₃P₃PtS (M_r) 1370.15): C, 58.73; H, 3.31; S, 2.34.

Found: C, 58.64; H, 3.10; S, 2.30. Λ_M: 122 Ω^-1‚cm²‚mol^-1. MS

ES (+): m/z 1220 ([M - TfO]⁺, 27%), 935 ([M - TfO - PPh₂Ct

CPh]⁺, 11%), 766 ([Pt(PPh₂CtCPh)₂]⁺, 36%). IR (cm^-1): ν(Ct

C) 2171 vs; ν(C₆F₅)_Xsens793 s; ν(CF₃SO₃) 1271 s, 1222 m, 1159

s, 1030 m. ¹H NMR (CDCl₃, 20 °C, δ): 7.70 (m, 5H), 7.41 (m, 12

H), 7.28 (m, 22H), 7.00 (d, 4H), 6.78 (d, 2H), Ph. ¹⁹F NMR (CDCl₃,

20 °C, δ): -78.2 (s, 3F, CF₃), -117.3 [dd, ³J(Pt-F_o) ) 262.6 Hz,

2F_o], -158.9 (t, 1F_p), -160.5 (m, 2F_m). ³¹P{¹H} NMR (CDCl₃, 20

1

3

129.0 [AXX′, J(C-P) + J(C-P) ) 63.9 Hz, C_i, PPh₂], 129.1

3

5

[“t”, J(C-P) + J(C-P) ) 11.6 Hz, C_m, PPh₂], 128.4 (s, C_m,

≡CPh), 119.8 (s, C_i, ≡CPh), 109.0 [AXX′, ²J(C-P) + ⁴J(C-P) )

16.1 Hz, C_â], 90.2 [st, J(C-P) ) 11.7 Hz, CHd, COD], 80.2

[AXX′, J(C-P) + J(C-P) ) 107.2 Hz, C_R], 31.3 (s, CH₂<,

COD).

1

°C, δ): -6.3 [d, 2P, J(P-P)_cis) 20 Hz, J(P-Pt) ) 2607 Hz],

1

3

-7.5 [m, br, P trans to C₆F₅, ¹J(P-Pt) ) 2339 Hz]. ¹³C{¹H} NMR

(CDCl₃, 20 °C, δ): 145.1-133.5 (C₆F₅), 134.0 [d, ²J(C-P) ) 12.6

Hz, C_o, PPh₂], 132.4-118.5 (PPh₂, Ph), 111.5 [AXX′, ²J(C-P) +

⁴J(C-P) ) 19.7 Hz, C_â, PPh₂C_R≡C_âPh cis to C₆F₅], 109.9 [d,

²J(C-P) ) 16.1 Hz, C_â, PPh₂CtCPh trans to C₆F₅], 80.5 [dt, ¹J(C-

P) ) 108.7 Hz, ³J(C-P) ) 5.3 Hz, C_R, PPh₂CtCPh trans to C₆F₅],

Synthesis of [Pt(o-C₆H₄O₂)(DMSO)₂], 4. To a solution of

potasium catecholate prepared by the treatment of catechol (0.078

g, 0.708 mmol) and potassium hydroxide (0.0795 g, 1.417 mmol)

in methanol (10 mL) was added cis-[PtCl₂(DMSO)₂] (0.299 g, 0.708

mmol) at room temperature. The initial grayish suspension became

yellow in a few minutes. The mixture was stirred for 4 h, and the

resulting suspension (complex 4) was filtered as a yellow solid

(0.304 g, 93% yield). Anal. Calcd for C₁₀H₁₆O₄PtS₂(M_r) 459.4):

C, 26.14; H, 3.51; S, 13.96. Found: C, 26.03; H, 3.42; S, 13.41.

MS ES (+): m/z 764 ([Pt₂(C₆H₄O₂)₂(DMSO)₂]⁺, 13%), 460 ([M]⁺,

1

3

77.9 [dd, J(C-P) + J(C-P) ) 63.5 Hz, C_R, PPh₂CtCPh cis to

C₆F₅].

Synthesis of [Rh(COD)(PPh₂C≡CPh)₂](ClO₄), 2. A yellow

solution of [Rh(µ-Cl)(COD)]₂(0.500 g, 1.014 mmol) in acetone

(20 mL) was treated with AgClO₄(0.420 g, 2.028 mmol). The

mixture was stirred for 1 h at room temperature and filtered through

Kieselguhr, and the resulting yellow filtrate was treated with

PPh₂CtCPh (1.161 g, 4.056 mmol). Immediately the brown-orange

solution obtained was evaporated to small volume (2 mL). By

addition of diethyl ether (10 mL) and cooling at -20 °C, an orange

microcrystalline solid (2) was obtained (1.220 g, 68% yield). Anal.

Calcd for C₄₈ClH₄₂O₄P₂Rh (M_r) 883.17): C, 65.28; H, 4.79.

Found: C, 64.96; H, 4.64. Λ_M: 116 Ω^-1‚cm²‚mol^-1. MS ES (+):

m/z 783 ([M - ClO₄]⁺, 100%). IR (cm^-1): ν(CtC) 2177 s;

1

100%). IR (cm^-1): ν(SdO) 1144 vs, 1134 vs. H NMR (CDCl₃,

20 °C, δ): 6.69 (m, 2H), 6.59 (m, 2 H) (C₆H₄), 3.53 [s, 12H, CH₃,

³J(H-Pt) ) 17.2 Hz]. ¹³C{¹H} NMR (CDCl₃, 20 °C, δ): 160.3 [s,

C¹(O), C₆H₄O₂], 118.1 (s, C³, C₆H₄O₂), 115.6 [³J(Pt-C) ) 52 Hz,

C², C₆H₄O₂], 44.39 [²J(Pt-C) ) 41.2 Hz, SO(CH₃)₂].

Synthesis of [Pt(o-C₆H₄S₂)(DMSO)₂], 5. cis-[PtCl₂(DMSO)₂]

(1.017 g, 2.408 mmol) was added to a solution of potasium benzene-

1,2-dithiolate (2.649 mmol) prepared with benzene-1,2-dithiol (300

µL, 2.649 mmol) and potassium hydroxide (0.297 g, 5.298 mmol)

in methanol (10 mL) at room temperature. The initial yellow

suspension turned dark gray in a few minutes. After 4 h of stirring,

5 was filtered off as a very dark gray solid (1.124 g, 95% yield).

Anal. Calcd for C₁₀H₁₆O₂PtS₄(M_r) 491.57): C, 24.43; H, 3.28;

S, 26.09. Found: C, 24.33; H, 2.56; S, 25.46. MS ES (+, Na⁺):

m/z 1968 ([4M + 2]⁺, 100%), 1007 ([2M + Na]⁺, 17%), 515 ([M

+ Na]⁺, 60%). IR (cm^-1): ν(SdO) 1157 s, 1126 s. ¹H NMR (HDA,

20 °C, δ): 7.30 (m, 2H), 6.83 (m, 2 H) (C₆H₄), 3.60 [s, 12H, CH₃,

³J(H-Pt) ) 17.3 Hz]. Its low solubility precluded its characteriza-

tion by ¹³C{¹H} NMR spectroscopy.

Synthesis of [Pt(o-C₆H₄O₂)(PPh₂C≡CPh)₂], 6.²⁸The synthesis

of this complex has been previously reported, but we found a

straightforward preparation from 4. A yellow suspension of [Pt(o-

C₆H₄O₂)(DMSO)₂], 4 (0.200 g, 0.436 mmol), in CH₂Cl₂(20 mL)

was treated with PPh₂CtCPh (0.262 g, 0.915 mmol), to give an

orange solution. After 2 h of stirring, the solution was filtered and

evaporated to dryness, and the residue was treated with a mixture

of 1:1 diethyl ether/n-hexane (6 mL), to give a pale-orange solid.

ν(ClO₄^-) 1092 vs, 623 m. H NMR (CDCl₃, 20 °C, δ): 7.67 (m,

1

8H), 7.40 (m, 12 H), 7.21 (m, 6H), 7.03 (m, 4H) Ph, 4.85 (s, br,

4H, CHd, COD), 2.55 (m, br, 4H, CH₂<, COD), 2.41 (m, br, 4H,

1

CH₂<, COD). ³¹P{¹H} NMR (CDCl₃, 20 °C, δ): 8.25 [d, J(P-

Rh) ) 150.1 Hz]. ¹³C{¹H} NMR (CDCl₃, 20 °C, δ): 133.4 [“t”,

4

²J(C-P) + J(C-P) ) 13.3 Hz, C_o, PPh₂], 131.9 (s, C_o, ≡CPh),

1

131.6 (s, br, C_p, PPh₂), 130.4 (s, C_p, ≡CPh), 129.6 [AXX′, J(C-

P) + ³J(C-P) ) 55.2 Hz, C_i, PPh₂], 129.2 [“t”, ³J(C-P) + ⁵J(C-

P) ) 11.2 Hz, C_m, PPh₂], 128.4 (s, C_m, ≡CPh), 120.1 (s, C_i, ≡CPh),

109.1 [“t”, ²J(C-P) + ⁴J(C-P) ) 14.3 Hz, C_â], 101.8 [dt, ¹J(C_R-

2

Rh) ∼ 1 Hz, J(C-P)_cis) 4.9 Hz, J(C-P)_trans) 7.3 Hz, CH),

(45) Uso´n, R.; Fornie´s, J.; Espinet, P.; Alfranca, G. Synth. React. Inorg.

Met. Org. Chem. 1980, 10, 579.

(46) Giordano, G.; Crabtree, R. H. Inorg. Synth. 1990, 28, 88.

(47) Herde, J. L.; Lambert, J. C.; Senoff, C. V. Inorg. Synth. 1974, 15, 18.

(48) Kitching, W.; Moore, C. J.; Doddrell, D. Inorg. Chem. 1970, 9, 541.

(49) Uso´n, R.; Fornie´s, J.; Toma´s, M.; Menjo´n, B. Organometallics 1985,

4, 1912.

(50) Charrier, C.; Chodkiewicz, W.; Cadiot, P. Bull. Soc. Chim. Fr. 1966,

1002.

Inorganic Chemistry, Vol. 43, No. 25, 2004 8187

Berenguer et al.

This solid was recrystallized from CH₂Cl₂/diethyl ether to afford 6

P²)_cis) 14.3 Hz, P³], -5.9 [dd, ¹J(P¹-Pt) ) 2486 Hz, J(P¹-P³)_trans

1

as an orange solid (0.253 g, 66% yield).

¹³C{¹H} NMR (CDCl₃, 20 °C, δ): 162.9 [t, J(C-P) + J(C-

) 362 Hz, J(P¹-P²)_cis) 14 Hz, P¹].

1

3

Synthesis of [(C₆F₅)(PPh₂C≡CPh)Pt{C₁₀H₄-1-C₆F₅-4-Ph-2,3-

κPP′(PPh₂)₂}](CF₃SO₃), 9. cis-[Pt(C₆F₅)₂(THF)₂] (0.081 g, 0.120

mmol) was added to a stirred solution of [Pt(C₆F₅)(PPh₂CtCPh)₃]-

(CF₃SO₃) (0.164 g, 0.120 mmol) in CH₂Cl₂(15 mL) at room

temperature, immediately forming an orange solution. After the

mixture was stirred for 54 h, the resulting black solution was

evaporated to a small volume (≈3 mL). The addition of diethyl

ether (10 mL) gave 9 as a gray solid (0.131 g, 71% yield). After

recrystallization in acetone/n-hexane complex 9 was obtained a light

gray solid (0.08 g, 43% yield). Anal. Calcd for C₇₃F₁₃H₄₅O₃P₃PtS‚

2CH₂Cl₂(M_r) 1705.99): C, 52.80; H, 2.84; S, 1.88. Found: C,

53.26; H, 2.99; S, 2.17. Λ_M: 114 Ω^-1‚cm²‚mol^-1. MS ES (+):

m/z 1387 ([M - TfO]⁺, 100%). IR (cm^-1): ν(CtC) 2174 s;

ν(C₆F₅)_X-sens781 m; ν(C₆F₅-C) 991 m, 989 m; ν(CF₃SO₃) 1275

P) ) 3 Hz, C¹(O), C₆H₄O₂], 133.6 [t, AXX′, J(C-P) + J(C-P)

) 12.8 Hz, C_o, PPh₂], 132.2 (s, C_o, ≡CPh), 131.1 (s, C_p, PPh₂),

130.3 (s, C_p, Ph), 128.9 [AXX′, five line pattern, ¹J(C-P) + ³J(C-

P) ) 59.7 Hz, C_i, PPh₂], 128.3 (m, C_mPPh₂, C_m≡CPh), 120.5 [t,

J(C-P) ) 1.5 Hz, C_i, ≡CPh], 116.2 (s, C³, C₆H₄O_2.), 115.4 [t,

J(C-P) ) 1.5 Hz, ³J(C-Pt) ) 58.6 Hz, C², C₆H₄O₂], 109.0 [AXX′,

2

4

1

²J(C-P) + J(C-P) ) 18.2 Hz, C_â, ≡C_âPh], 79.0 [AXX′, J(C-

3

P) + J(C-P) ) 120.2 Hz, C_R, C_R≡].

Synthesis of [Pt(o-C₆H₄S₂)(PPh₂C≡CPh)₂], 7. A 0.460 g (1.608

mmol) amount of PPh₂CtCPh was added to a black suspension

of [Pt(o-C₆H₄S₂)(DMSO)₂] (5) (0.395 g, 0.804 mmol) in CH₂Cl₂

(20 mL), and the mixture was stirred for 2 h. The resulting black

solution was evaporated to dryness and the residue treated with

diethyl ether (20 mL) to yield a gray solid (0.615 g, 84% yield).

Crystallization at room temperature in aerobic conditions from an

acetone solution gave yellow crystals, containing solvated acetone

7‚CH₃COCH₃, suitable for X-ray diffraction. ¹H and ³¹P NMR

spectra of both samples (gray solid and yellow crystals) are

essentially identical except for the presence of coordinated acetone

in the crystals. Anal. Calcd for C₄₆H₃₄P₂PtS₂‚CH₃COCH₃(M_r)

966.01): C, 60.92; H, 4.17; S, 6.64. Found: C, 60.51; H, 3.97; S,

6.56. MS ES (+): m/z 908 ([M]⁺, 100%). IR (cm^-1): ν(CtC)

1

s, br, 1225 m, 1157 s, br, 1031 s. H NMR (CDCl₃, 20 °C, δ):

7.82-6.30 (m, 38H), 6.24 (d, J ) 7.5 Hz, 2H). ¹⁹F NMR (CDCl₃,

3

20 °C, δ): -78.4 (s, 3F, CF₃), -116.7 [m, J(Pt-F_o) ) 199 Hz,

2F_o], -133.6 [d, J ) 17.4 Hz, 2F_o, C-C₆F₅], -150.0 (t, 1F_p,

C-C₆F₅), -158.4 (t, 1F_p), -159.5 (m, br, 2F_m, C-C₆F₅), -162.0

(m, 2F_m). ³¹P{¹H} NMR (CDCl₃, 20 °C, δ): 48.3 [s, br, ¹J(P²-Pt)

1

) 2196 Hz, P²trans to C₆F₅], 43.1 [dd, J(P³-Pt) ) 2410 Hz,

2

²J(P³-P¹)_trans) 364 Hz, J(P³-P²)_cis) 15.6 Hz, P³], -5.5 [dd,

¹J(P¹-Pt) ) 2566 Hz, ²J(P¹-P³)_trans) 364 Hz, ²J(P¹-P²)_cis) 12.9

Hz, P¹].

1

2176 vs. H NMR (yellow crystals, CDCl₃, 20 °C, δ): 7.82 (m,

Reaction of [Rh(COD)(PPh₂C≡CPh)₂](ClO₄), 2, with cis-[Pt-

(C₆F₅)₂(THF)₂]. cis-[Pt(C₆F₅)₂(THF)₂] (0.076 g, 0.113 mmol) was

added to a stirred solution of [Rh(COD)(PPh₂CtCPh)₂](ClO₄), 2

(0.100 g, 0.113 mmol), in CH₂Cl₂(15 mL) at 20 °C, immediately

forming an orange solution. Monitoring the reaction by multinuclear

NMR spectroscopy in CDCl₃at room temperature revealed the

presence after 10 min of several products containing C-C₆F₅[δ_F

-125.5, -131.3, -138.5, -141.4 (F_o), -152.9, -153.5, -158.1,

-159.8 (F_p)], starting material (2), and cis-[Pt(C₆F₅)₂(PPh₂Ct

CPh)₂]. After 8 h of reaction, the same mixture was observed but

in different proportions. Attempts to obtain a pure insertion product

were unsuccessful.

8H), 7.33 (m), 7.17 (t), 6.98 (d, 24H), 6.70 (m, 2H), Ph, C₆H₄,

1

2.16 (CH₃). ³¹P{¹H} NMR (CDCl₃, 20 °C, δ): -4.7 [s, J(Pt-P)

) 2909 Hz]. ¹³C{¹H} NMR (CDCl₃, 20 °C, δ): 207.0 (CdO,

acetone), 145.8 [AXX′, ¹J(C-P) + ³J(C-P) ) 15.6 Hz, C¹-S,

2

4

C₆H₄S₂], 133.9 [AXX′, five line pattern J(C-P) + J(C-P) )

12.8 Hz, C_o, PPh₂], 132.2 (s, C_o, Ph), 131.0 (s, C_p, PPh₂), 130.1

[AXX′, five line pattern, ¹J(C-P) + ³J(C-P) ) 67.8 Hz, C_ι, PPh₂],

3

130.0 (s, C_p, Ph), 128.2 [t, J(C-P) ∼ 0.5 Hz, J(C-Pt) ∼ 67 Hz,

C², C₆H₄S₂], 128.2 (t, C_mPPh₂, C_mPh), 121.5 (s, br, C³, C₆H₄S₂),

2

120.8 [t, J(C-P) ∼ 1 Hz, C_i, ≡CPh], 108.0 [AXX′, J(C-P) +

⁴J(C-P) ) 16.3 Hz, C_â, ≡C_âPh], 81.1 [d, J(C-P) ) 111.5 Hz,

C_R, C_R≡], 31.0 (s, CH₃, acetone).

Reaction of [Ir(COD)(PPh₂C≡CPh)₂](ClO₄), 3, with cis-[Pt-

(C₆F₅)₂(THF)₂]. A mixture of cis-[Pt(C₆F₅)₂(THF)₂] (0.045 g, 0.067

mmol) and [Ir(COD)(PPh₂CtCPh)₂](ClO₄), 3 (0.065 g, 0.067

mmol), was dissolved at -40 °C in CH₂Cl₂(15 mL), and the

orange-brown solution obtained was layered with n-hexane. Cooling

at -40 °C for 1 week afforded white crystals of [(C₆F₅)₂Pt(µ-κO:

η²-PPh₂(O)CtCPh)]₂, 10, and a dark-brown oil. NMR multinuclear

study of this oil indicates the presence of a very impure insertion

product together with an small amount of 3. ¹⁹F NMR (CDCl₃, 20

°C, δ): -117 to -122 (br, F_o), -124.5 (F_o, C-C₆F₅), -132.2 (F_o,

C-C₆F₅), -153.2 (F_p, C-C₆F₅), -159.5 to -166.5 (F_p, F_m). ³¹P-

{¹H} NMR (CDCl₃, 20 °C, δ): 40.9 [d, J(P-P) ) 18 Hz], 27.9

[d, J(P-P) ) 18 Hz]. Similar results were obtained by monitoring

the reaction at room temperature.

Synthesis of [(C₆F₅)₂Pt(µ-κO:η²-PPh₂(O)C≡CPh)]₂, 10. To a

solution of cis-[Pt(C₆F₅)₂(THF)₂] (0.150 g, 0.223 mmol) in CH₂-

Cl₂was added 0.067 g (0.223 mmol) of PPh₂(O)CtCPh. After 5

min of stirring, a white solid precipitates. The solid was filtered

out (0.15 g, 81% yield). Anal. Calcd for C₃₂F₁₀H₁₅OPPt: C, 46.22;

H, 1.82. Found: C, 46.03; H, 1.90. IR (cm^-1): ν(CtC) 1981 s;

ν(P-O) 1165 s; ν(C₆F₅)_X-sens815 s, 803 s.

Synthesis of [Pt(C₆F₅)(OH₂)µ-{C(Ph)dC(PPh₂)C(PPh₂)d

C(Ph)(C₆F₅)}Pt(C₆F₅)(PPh₂C≡CPh)](CF₃SO₃), 8. cis-[Pt(C₆F₅)₂-

(THF)₂] (0.074 g, 0.110 mmol) was added to a colorless solution

of [Pt(C₆F₅)(PPh₂C≡CPh)₃](CF₃SO₃), 1 (0.150 g, 0.110 mmol), in

CH₂Cl₂(15 mL) at room temperature, immediately forming an

orange solution. After being stirred for 10 min, the solution was

evaporated to small volume (2 mL). The addition of n-hexane (10

mL) gave 8 as an orange solid (0.139 g, 67% yield). Anal. Calcd

for C₇₉F₁₈H₄₅O₃P₃Pt₂S‚0.5H₂O‚0.5THF (M_r)1944.42): C, 50.04;

H, 2.59; S, 1.65. Found: C, 49.99; H, 2.55; S, 1.36. Λ_M: 118

Ω^-1‚cm²‚mol^-1. MS ES (+): m/z 1750 ([M - TfO]⁺, 100%), 1582

([M - TfO - C₆F₅]⁺, 17%), 1387 ([M - TfO - Pt(C₆F₅)]⁺, 38%).

IR (cm^-1): ν(OH) 3604 w; ν(CtC) 2175 vs; ν(C₆F₅) 1519 vs,

1504 s, 1063 s, 980 s, 959 vs, 804 m, 799 m; ν(CF₃SO₃) 1293 (s),

1

1232 (m), 1161 (s), 1030 (s). H NMR (CDCl₃, 20 °C, δ): 9.17

(m, 2H), 7.98 (m, 4H), 7.71-6.43 (m, 35H), 6.10 (br, 2H), 5.35

(d, J ) 7.1 Hz) (aromatics), 3.71 (s, br, OCH₂, THF), 1.82 (s, br,

CH₂, THF), 1.70 (s, H₂O). ¹⁹F NMR (CDCl₃, 20 °C, δ): -78.4 (s,

3

3F, CF₃), -113.9 [m, J(Pt-F_o) ) 230 Hz, 2F_o], -115.6 [m, J-

(Pt-F_o) ∼ 225 Hz, 2F_o], -122.1 (m, br, 1F_oA), -133.3 [d, ⁴J(Pt-

F_o) ∼ 75 Hz, 1F_oA], -153.3 (br, 1F_pA), -158.8 (t, 1F_p), -159.1 (t,

1F_p), -160.3 (m, br, 2F_m), -161.6 (m, 1F_m), -162.5 (m, 1F_m),

-164.1 (m, br, 2F_m). ³¹P{¹H} NMR (CDCl₃, 20 °C, δ): 32.4 [s,

br, ¹J(P²-Pt) ) 2214 Hz, P²trans to C₆F₅], 28.2 [dd, ¹J(P³-Pt) )

Synthesis of [Pt(PPh₂C≡CPh)(µ-κO-o-C₆H₄O₂)(µ-κP:η²-PPh₂-

C≡CPh)Pt(C₆F₅)₂], 11. cis-[Pt(C₆F₅)₂(THF)₂] (0.094 g, 0.140

mmol) was added to an orange solution of [Pt(o-C₆H₄O₂)(PPh₂Ct

CPh)₂] (6) (0.102 g, 0.116 mmol) in CH₂Cl₂(20 mL), and the

2

1

2428 Hz, J(P³-Pt) ) 530 Hz, J(P³-P¹)_trans) 362 Hz, J(P³-

8188 Inorganic Chemistry, Vol. 43, No. 25, 2004

Alkynyldiphenylphosphine d⁸(Pt, Rh, Ir) Complexes

mixture was stirred for 1 h. The solution was treated with charcoal

and filtered through Kieselgurh. The yellow solution obtained was

evaporated to small volume (2 mL) and treated with n-hexane (5

mL) to give 11 as a yellow-brown solid (0.149 g, 85% yield). Anal.

Calcd for C₅₈F₁₀H₃₄O₂P₂Pt₂.CH₂Cl₂(M_r) 1489.95): C, 47.56; H,

2.44. Found: C, 47.71; H, 2.31. MS ES (+): m/z 1405 ([M]⁺,

5%), 766 ([Pt(PPh₂CtCPh)₂]⁺, 35%). IR (cm^-1): ν(CtC) 2175

vs, 1968 s, br; ν(C₆F₅)_Xsens802 vs, br. ¹H NMR (CDCl₃, 20 °C, δ):

8.12 (m, 3H), 7.94 (m, 4H), 7.60-7.12 (m, 20H), 7.03 (d, J ) 7.4

Hz, 1H), 6.96 (d, J ) 7.7 Hz, 1H), 6.74 (d, J ) 7.5 Hz, 2H), 6.55

(d, 1H), 6.48 (t, 1H), 6.30 (t, 1H), (Ph, C₆H₄). ¹⁹F NMR (CDCl₃,

-163.6 (m, br, 4F_m), -164.3 (m, 4F_m). ³¹P{¹H} NMR (CDCl₃, 20

1

3

°C, δ): -1.2 [s, J(Pt-P) ) 3117 Hz, J(Pt-P) ) 43 Hz].

X-ray Crystallography. Table 1 reports details of the structural

analyses for all complexes. Colorless (1, 9, 10) or yellow (2, 8,

14) crystals were obtained by slow diffusion of n-hexane into a

dichloromethane (1, 10, 9, at room temperature), chloroform (2, at

room temperature), tetrahydrofuran (8), or toluene (14) solution of

each compound at -30 °C, while yellow crystals of 7‚acetone were

obtained by leaving an acetone solution of this complex to evaporate

at room temperature. For complexes 1, 9, and 10, 1, 2, and 0.75

molecules of CH₂Cl₂and for complex 8 3 molecules of THF were

found, respectively, in the asymmetric unit. Complex 7 crystallizes

with one molecule of acetone. X-ray intensity data were collected

with a Nonius κCCD area-detector diffractometer, using graphite-

monochromated Mo KR radiation. Images were processed using

the DENZO and SCALEPACK suite of programs,⁵¹carrying out

the absorption correction at this point for complex 2. For the rest

of complexes, the absorption correction was performed using

SORTAV,⁵²except for complex 9 for which an empirical absorption

correction was done using XABS2.⁵³All the structures were solved

by Patterson and Fourier methods using the DIRDIF92 program⁵⁴

and refined by full-matrix least squares on F²with SHELXL-97.⁵⁵

All non-hydrogen atoms were assigned anisotropic displacement

parameters, and all hydrogen atoms were constrained to idealized

geometries fixing isotropic displacement parameters of 1.2 times

the U_isovalue of their attached carbon for the phenyl and methine

hydrogens and 1.5 for the methyl groups. For 14, one phenyl ring

(C(3)-C(8)) was refined as an idealized aromatic ring, and for 1‚

CH₂Cl₂, 8‚3C₄H₈O, and 10‚1.5CH₂Cl₂, one solvent molecule

showed positional disorder and was modeled adequately. For

complexes 1‚CH₂Cl₂, 8‚3C₄H₈O, 9‚2CH₂Cl₂, 10‚1.5CH₂Cl₂, and 14,

residual peaks bigger than 1 e Å^-3close to their respective platinum

atoms have been observed but with no chemical meaning. For

complex 10, three peaks slightly bigger than 1 e Å^-3are also

observed in the vicinity of the solvent.

3

20 °C, δ): -118.7 [m, J(Pt-F_o) ∼ 375 Hz, 3F_o], -119.1 [m, J-

(Pt-F_o) ∼ 310 Hz, 1F_o], -161.5 (t, 1F_p), -162.5 (t, 1F_p), -163.8

(m, 1F_m), -164.9 (m, 1F_m), -165.6 (m, 2F_m). ³¹P{¹H} NMR

(CDCl₃, 20 °C, δ): -2.7 [d, ¹J(Pt-P¹) ) 3404 Hz, J(P¹-P²) ) 27

1

Hz, P¹bridge], -24.8 [d, J(Pt-P²) ) 4056 Hz, P²terminal].

Synthesis of [Pt(PPh₂C≡CPh)(µ-κS-o-C₆H₄S₂)(µ-κP:η²-PPh₂-

C≡CPh)Pt(C₆F₅)₂], 12. This complex was obtained as a grayish

product in a way similar to that for 11 but starting from [Pt(o-

C₆H₄S₂)(PPh₂CtCPh)₂] (7) (0.078 g, 0.086 mmol) and cis-[Pt-

(C₆F₅)₂(THF)₂] (0.058 g, 0.0865 mmol) (0.071 g, 57% yield). Anal.

Calcd for C₅₈F₁₀H₃₄P₂Pt₂S₂‚CH₂Cl₂(M_r) 1522.07): C, 46.56; H,

2.38; S 4.21. Found: C, 46.32; H, 2.15; S 4.20. MS ES (+): m/z

933 ([Pt(C₆F₅)₂(PPh₂CtCPh)₂] - H]⁺, 100%), 909 ([Pt(o-C₆H₄S₂)-

(PPh₂CtCPh)₂(7) + H]⁺, 52%), 668 ([Pt(o-C₆H₄S₂)(C₆F₅)₂] -

H]⁺, 39%). IR (cm^-1): ν(CtC) 2174 vs, 1975 m, br; ν(C₆F₅)_Xsens

1

804 s, 793 s. H NMR (CDCl₃, 20 °C, δ): 7.79 (m, 8H), 7.47-

7.10 (m, 22H), 6.97 (d, J ) 7.4 Hz, 2H) (Ph, C₆H₄), 6.79 (t, 1H),

6.65 (t, 1H) (C₆H₄). ¹⁹F NMR (CDCl₃, 20 °C, δ): -115.5 [m, br,

³J(Pt-F_o) ∼ 415 Hz, 2F_o], -116.8 [dm, ³J(Pt-F_o) ) 385 Hz, 2F_o],

-162.0 (t, 1F_p), -163.3 (t, 1F_p), -164.4 (m, 2F_m), -164.9 (m,

2F_m). ³¹P{¹H} NMR (CDCl₃, 20 °C, δ): 5.0 [d, ¹J(Pt-P¹) ) 2810

1

Hz, J(P¹-P²) ) 29 Hz, P¹bridge], -13.5 [d, J(Pt-P²) ) 3184

Hz, P²terminal].

Synthesis of [{Pt(µ₃-κ²O,O′-o-C₆H₄O₂)(µ-κP:η²-PPh₂C≡CPh)₂}-

{Pt(C₆F₅)₂}₂], 13. To an orange solution of [Pt(o-C₆H₄O₂)(PPh₂Ct

CPh)₂] (6) (0.102 g, 0.117 mmol) in CH₂Cl₂(20 mL) was added

cis-[Pt(C₆F₅)₂(THF)₂] (0.173 g, 0.257 mmol). The color of the

resulting solution changed from orange to yellow-brown. The

mixture was stirred for 2 h and then filtered through Kieselgurh.

The filtrate was concentrated to small volume (2 mL) and treated

with n-hexane (5 mL) to give 13 as a white solid (0.179 g, 80%

yield). Anal. Calcd for C₇₀F₂₀H₃₄O₂P₂Pt₃(M_r) 1934.26): C, 43.47;

H, 1.77. Found: C, 43.68; H, 1.72. MS ES (+): m/z 766 ([Pt-

(PPh₂CtCPh)₂]⁺, 30%), 875 ([6], 10%). IR (cm^-1): ν(CtC) 1968

s, br; ν(C₆F₅)_Xsens799 vs, br. ¹H NMR (CDCl₃, 20 °C, δ): 7.91 (d,

br), 7.62-7.31 (m, 26H) Ph, 6.76 (s, br, 2H), 6.32 (s, br, 2H) C₆H₄.

Results and Discussion

Mononuclear Complexes. The synthesis of mononuclear

complexes is shown in Scheme 1. The cationic tris-

(phosphine)platinum complex [Pt(C₆F₅)(PPh₂CtCPh)₃](CF₃-

SO₃), 1, is isolated as a white solid by removing the chlorine

ligands in [Pt(µ-Cl)(C₆F₅)(tht)]₂(tht ) tetrahydrothiophene)

with AgCF₃SO₃(2 equiv) and subsequent treatment with

PPh₂CtCPh (6 equiv) in acetone (Scheme 1, path i).

Similarly, as shown in Scheme 1, path ii, the cationic

rhodium and iridium derivatives [M(COD)(PPh₂CtCPh)₂]-

(ClO₄) (M ) Rh, 2, and Ir, 3) are obtained as orange (2) or

pink (3) solids from the cationic species [M(COD)(acetone)_x]-

(ClO₄) (M ) Rh, Ir), prepared in situ in acetone (see

Experimental Section for details) with the alkynylphosphine

PPh₂CtCPh (4 equiv).

3

¹⁹F NMR (CDCl₃, 20 °C, δ): -118.2 [m, J(Pt-F_o) ∼ 425 Hz],

-119.3 (m, br), 8F_o, -160.8 (br, 2F_p), -161.4 (t, 2F_p), -164.0

(m, br, 4F_m), -165.0 (m, 4F_m). ³¹P{¹H} NMR (CDCl₃, 20 °C, δ):

1

-10.7 [s, J(Pt-P) ) 3813 Hz].

Synthesis of [{Pt(µ₃-κ²S,S′-o-C₆H₄S₂)(µ-κP:η²-PPh₂C≡CPh)₂}-

{Pt(C₆F₅)₂}₂], 14. By a procedure similar to that described for 13,

[Pt(o-C₆H₄S₂)(PPh₂CtCPh)₂] (7) (0.150 g, 0.165 mmol) and cis-

[Pt(C₆F₅)₂(THF)₂] (0.250 g, 0.371 mmol) gave 14 as a brown solid

(0.320 g, 93% yield). Anal. Calcd for C₇₀F₂₀H₃₄P₂Pt₃S₂(M_r)

1966.35): C, 42.76; H, 1.74; S, 3.26. Found: C, 42.54; H, 1.63;

S, 3.03. MS ES (+): m/z 933 ([Pt(C₆F₅)₂(PPh₂CtCPh)₂] - H]⁺,

100%). IR (cm^-1): ν(CtC) 1978 s, br; ν(C₆F₅)_Xsens806 vs, 794

vs. ¹H NMR (CDCl₃, 20 °C, δ): 7.79 (d, J ) 7.5 Hz, 6H), 7.53-

7.25 (m, 24H) Ph, 7.14 (m, 2H), 6.85 (m, 2H) C₆H₄. ¹⁹F NMR

(CDCl₃, 20 °C, δ): -115.8 [m, ³J(Pt-F_o) ) 388 Hz, 4F_o], -117.8

(51) Otwinowski, Z.; Minor, W. In Methods in Enzymology; Carter, C. V.,

Jr., Sweet, R. M., Eds.; Academic Press: New York, 1997; Vol. 276A,

p 307.

(52) Blessing, R. H. Acta Crystallogr. 1995, A51, 33.

(53) Parkin, S.; Moezzi, B.; Hope, H. J. Appl. Crystallogr. 1995, 28, 53.

(54) Beursken, P. T.; Beursken, G.; Bosman, W. P.; de Gelder, R.; Garc´ıa-

Granda, S.; Gould, R. O.; Smith, J. M. M.; Smykalla, C. The

DIRDIF92 program system; Technical Report of the Crystallography

Laboratory, University of Nijmegen: Nijmegen, The Netherlands,

1992.

(55) Sheldrick, G. M. SHELX-97, a program for the refinement of crystal

structures; University of Go¨ttingen: Go¨ttingen, Germany, 1997.

3

[m, J(Pt-F_o) ) 330 Hz, 4F_o], -161.1 (br, 2F_p), -162.1 (t, 2F_p),

Inorganic Chemistry, Vol. 43, No. 25, 2004 8189

Berenguer et al.

Table 1. Crystallographic Data for Compounds [Pt(C₆F₅)(PPh₂CtCPh)₃](CF₃SO₃)‚CH₂Cl₂, 1‚CH₂Cl₂; [Rh(COD)(PPh₂CtCPh)₂](ClO₄), 2;

[Pt(o-C₆H₄S₂)(PPh₂CtCPh)₂]‚CH₃COCH₃, 7‚CH₃COCH₃; [Pt(C₆F₅)(OH₂)µ-{C(Ph)dC(PPh₂)C(PPh₂)C(PPh₂)dC(Ph)(C₆F₅)}Pt(C₆F₅)-

(PPh₂C≡CPh)](CF₃SO₃)‚3THF; 8‚3THF, [(C₆F₅)(PPh₂CtCPh)Pt{C₁₀H₄-1-C₆F₅-4-Ph-2,3-κPP′(PPh₂)₂}](CF₃SO₃)‚2CH₂Cl₂, 9‚2CH₂Cl₂;

[(C₆F₅)₂Pt(µ-κO:η²-PPh₂(O)CtCPh)]₂‚1.5CH₂Cl₂, 10‚1.5CH₂Cl₂; and [{Pt(µ-κS:S′-o-C₆H₄S₂)(µ-κP:η²-PPh₂CtCPh)₂}₂{Pt(C₆F₅)₂}₂], 14

1‚CH₂Cl₂

2

7‚CH₃COCH₃

8‚3THF

empirical formula

M_w

C₆₈H₄₇Cl₂F₈O₃P₃PtS

1455.02

C₄₈H₄₂ClO₄P₂Rh

883.12

C₄₉H₄₀OP₂PtS₂

965.96

C₉₁H₆₉F₁₈O₇P₃Pt₂S

2131.61

T, K

173(1)

223(1)

173(1)

λ(Μï ΚR), Å

0.710 73

cryst system, space group

triclinic, P1h

0.6 × 0.4 × 0.3

12.4836(2);

99.2020(10)

15.6758(3);

98.6290(10)

16.1148(3);

92.353(2)

monoclinic, P2₁/c

0.35 × 0.25 × 0.10

9.76160(10);

90

20.5301(3);

99.9280(10)

20.6733(3);

90

orthorhombic, Pnca

0.35 × 0.2 × 0.2

10.64900(10);

90

14.82700(10);

90

26.8650(3);

90

4241.79(7); 4

1.513

monoclinic, P2₁/a

0.3 × 0.25 × 0.075

15.66040(10);

90

23.0236(2);

94.44

23.3432(2);

90

8391.38(12); 4

1.687

cryst dimens, mm

a, Å;

R, deg

b, Å;

â, deg

c, Å;

γ, deg

V, Å³; Z

3070.85(10); 2

1.574

2.556

4081.02(9); 4

1.437

0.607

F

_calcd, Mg/m³

abs coeff, mm^-1

F(000)

3.518

1928

3.509

4200

1448

1816

θ range for data collcn, deg

4.09-27.88

-16 e h e 16,

-20 e k e 20,

-21 e l e 21

46 433

1.41-29.85

0 e h e 12,

-26 e k e 0,

-28 e l e 25

9681

4.09-27.87

-13 e h e 14,

-19 e k e 19,

-33 e l e 35

65 350

4.12-26.37

-19 e h e 19,

-28 e k e 28,

-29 e l e 29

103 763

index ranges

reflns collcd

refinement method

full-matrix least-

squares on F²

14 397/2/794

1.035

R1 ) 0.0416,

wR2 ) 0.1007

R1 ) 0.0511,

wR2 ) 0.1059

1.734 and -2.025

full-matrix least-

squares on F²

9681/0/505

1.022

R1 ) 0.0404,

wR2 ) 0.0839

R1 ) 0.0623,

wR2 ) 0.0935

0.784 and -0.656

full-matrix least-

squares on F²

5045/0/251

0.991

R1 ) 0.0253,

wR2 ) 0.0511

R1 ) 0.0432,

wR2 ) 0.0574

0.868 and -0.697

full-matrix least-

squares on F²

17 095/5/1051

1.043

R1 ) 0.0454,

wR2 ) 0.1078

R1 ) 0.0606,

wR2 ) 0.1157

4.790 and -2.304

data/restraints/params

GOF on F^{2 a}

final R indices [I > 2σ(I)]^a

R indices (all data)^a

largest diff peak and hole, e‚Å^-3

9‚2CH₂Cl₂

10‚1.5CH₂Cl₂

14

empirical formula

M_w

C₇₅H₄₈Cl₄F₁₃O₃P₃PtS

1705.99

C_65.5H₃₃Cl₃F₂₀O₂P₂Pt₂

1790.39

C₇₀H₃₄F₂₀P₂Pt₃S₂

1966.30

T, K

173(1)

223(1)

λ(Μï ΚR), Å

0.710 73

cryst system, space group

monoclinic, P2₁/c

0.70 × 0.075 × 0.075

20.1780(3);

90

15.3627(2);

104.3490(10)

23.0999(3);

90

triclinic, P1h

0.4 × 0.25 × 0.2

11.6299(2);

102.8900(10)

12.1801(2);

100.5700(10)

12.2589(2);

99.7760(10)

1623.30(5); 1

1.831

triclinic, P1h

0.42 × 0.20 × 0.15

15.3996(3);

107.1250(10)

15.7509(2);

93.3460(10)

18.5369(4);

109.9680(10)

3974.89(13); 2

1.643

cryst dimens, mm

a, Å;

R, deg

b, Å;

â, deg

c, Å;

γ, deg

V, Å³; Z

6937.32(16); 4

1.633

2.360

F

_calcd, Mg/m³

abs coeff, mm^-1

F(000)

4.579

859

5.441

1860

3384

θ range for data collcn, deg

1.04-25.03

-24 e h e 24,

-18 e k e 18,

-27 e l e 27

55 199

2.22-27.90

-15 e h e 15,

-16 e k e 15,

-16 e l e 16

25 706

4.11-25.68

-18 e h e 18,

-19 e k e 19,

-22 e l e 22

42 871

index ranges

reflns colld

refinement method

full-matrix least-

squares on F²

12 146/0/901

1.049

R1 ) 0.0520,

wR2 ) 0.1490

R1 ) 0.0801,

wR2 ) 0.1822

1.444 and -3.358

full-matrix least-

squares on F²

7694/3/421

1.055

R1 ) 0.0380,

wR2 ) 0.0961

R1 ) 0.0444,

wR2 ) 0.0995

2.637 and -2.709

full-matrix least-

squares on F²

14 635/9/875

1.054

R1 ) 0.0428,

wR2 ) 0.1134

R1 ) 0.0580,

wR2 ) 0.1252

1.222 and -1.719

data/restraints/params

GOF on F^{2 a}

final R indices [I > 2σ(I)]^a

R indices (all data)^a

largest diff peak and hole, e‚Å^-3

2

^aR1 ) Σ(|F_o| - |F_c|)/Σ|F_o|; wR2 ) [Σw(F_o²- F_c)²/ΣwF_o]^1/2; GOF ) Σw(F_o²- F_c)²/(N_obs- N_param)]; w ) [σ²(F_o) + (g₁P)²+ g₂P]^-1; P ) [max(F_o

2

+ 2F_c]/3.

Finally, the neutral platinum derivatives [Pt(o-C₆H₄E₂)-

[Pt(o-C₆H₄O₂)(DMSO)₂], 4, or 1,2-benzenedithiolate [Pt(o-

C₆H₄S₂)(DMSO)₂], 5, complexes (also prepared in this work),

with 2 equiv of the alkynylphosphine (Scheme 1, path iii).

It should be mentioned that the synthesis of complex

(PPh₂CtCPh)₂] (E ) O, 6, and S, 7) are synthesized as pale-

orange (6) or gray (7) solids by displacing the dimethyl

sufoxide (DMSO) ligands from the neutral catecholate

8190 Inorganic Chemistry, Vol. 43, No. 25, 2004

Alkynyldiphenylphosphine d⁸(Pt, Rh, Ir) Complexes

Scheme 1

Table 2. Selected Bond Lengths (Å) and Angles (deg) for Complexes [Pt(C₆F₅)(PPh₂CtCPh)₃](CF₃SO₃)‚CH₂Cl₂, 1‚CH₂Cl₂;

[Rh(COD)(PPh₂CtCPh)₂](ClO₄), 2; and [Pt(o-C₆H₄S₂)(PPh₂CtCPh)₂]‚CH₃COCH₃, 7‚CH₃COCH₃

Complex 1‚CH₂Cl₂

Pt(1)-C(61)

Pt(1)-P(2)

Pt(1)-P(1)

Pt(1)-P(3)

2.084(4)

P(3)-C(1)

P(2)-C(21)

P(1)-C(41)

1.744(4)

1.747(4)

1.750(4)

C(1)-C(2)

C(21)-C(22)

C(41)-C(42)

1.199(6)

1.201(6)

1.191(6)

2.3161(10)

2.3234(10)

2.3288(10)

C(61)-Pt(1)-P(1)

P(2)-Pt(1)-P(1)

C(61)-Pt(1)-P(3)

P(2)-Pt(1)-P(3)

88.75(11)

92.21(4)

86.68(11)

92.26(4)

C(2)-C(1)-P(3)

C(1)-C(2)-C(3)

C(22)-C(21)-P(2)

173.3(4)

178.0(5)

174.8(4)

C(21)-C(22)-C(23)

C(42)-C(41)-P(1)

C(41)-C(42)-C(43)

179.3(5)

172.3(4)

179.4(5)

Complex 2

Rh(1)-C(44)

Rh(1)-C(41)

Rh(1)-C(42)

Rh(1)-C(43)

2.210(3)

2.226(3)

2.232(3)

2.262(3)

Rh(1)-P(2)

Rh(1)-P(1)

P(1)-C(1)

2.2995(7)

2.3337(7)

1.694(3)

P(2)-C(9)

C(1)-C(2)

C(9)-C(10)

1.673(3)

1.168(4)

1.152(4)

C(41,42)-Rh(1)-P(2)

C(43,44)-Rh(1)-P(1)

P(2)-Rh(1)-P(1)

85.93

84.23

98.25(2)

C(1)-P(1)-Rh(1)

C(9)-P(2)-Rh(1)

C(2)-C(1)-P(1)

115.39(11)

109.04(11)

168.1(3)

C(1)-C(2)-C(3)

C(10)-C(9)-P(2)

C(9)-C(10)-C(11)

175.2(3)

176.3(3)

176.1(3)

Complex 7‚ CH₃COCH₃

Pt(1)-P(1)

Pt(1)-S(1)

2.2745(7)

2.3052(7)

P(1)-C(4)

S(1)-C(1)

1.759(3)

1.760(3)

C(1)-C(1a)

C(4)-C(5)

1.393(7)

1.199(4)

P(1a)-Pt(1)-P(1)

P(1)-Pt(1)-S(1)

S(1)-Pt(1)-S(1a)

93.58(4)

88.84(3)

88.79(4)

C(1a)-C(1)-S(1)

C(2)-C(1)-S(1)

121.37(11)

119.7(3)

C(5)-C(4)-P(1)

C(4)-C(5)-C(6)

172.5(3)

177.0(3)

[Pt(o-C₆H₄O₂)(PPh₂CtCPh)₂], 6, has been previously re-

ported,²⁸although in lower yield by reacting directly [PtCl₂-

(PPh₂CtCPh)₂] in CHCl₃with deprotonated catechol in

MeOH. However, in our hands, this procedure yielded a

complex mixture of products (with 6 being the major

component) from which complex 6 can be separated after

repeated crystallizations in very low yield. A solution of [Pt-

(o-C₆H₄S₂)(PPh₂CtCPh)₂], 7, in acetone forms bright yellow

crystals of [Pt(o-C₆H₄S₂)(PPh₂CtCPh)₂]‚CH₃COCH₃(7‚CH₃-

COCH₃) suitable for X-ray diffraction. Despite the different

color of both samples, the only significant difference between

7 and 7‚CH₃COCH₃in their spectroscopic data is the

presence of acetone.

X-ray diffraction. The IR spectra of phosphine complexes

show one ν(CtC) strong absorption in the 2171-2177 cm^-1

region thus confirming the P-coordination mode of the

PPh₂CtCPh ligand.^{2-6,15,40,41,43,56}The bis(alkynylphosphine)

complexes (2, 3, 6, 7) exhibit a singlet phosphorus resonance

(range δ -14.5 to 8.25), downfield shifted with respect to

that of free PPh₂CtCPh (δ -33.55), and as expected, the

tris(alkynylphosphine) complex 1 shows a doublet at δ -6.3,

attributed to the two phosphines mutually trans, and a signal

at δ -7.5, assigned to the phosphine ligand trans to C₆F₅,

which appears as a multiplet due to additional unresolved

coupling to fluorine atoms. The ¹³C{¹H} NMR spectra are

particularly significant. In all complexes, the C_Rcarbon

resonances are shifted upfield (δ 77.9-81.1) with respect

to that of free PPh₂CtCPh (δ(C_R) 86.5), this effect being

similar in cationic or neutral complexes. The acetylenic C_â

carbon resonances lie very close to that of the free ligand

All complexes are air-stable and have been characterized

by the usual analytical and spectroscopic techniques. Ad-

ditionally, the molecular structures of the cationic 1, 2, and

neutral 7‚CH₃COCH₃derivatives have been determined by

Inorganic Chemistry, Vol. 43, No. 25, 2004 8191

Berenguer et al.

Figure 1. Molecular structure of the cation [Pt(C₆F₅)(PPh₂CtCPh)₃]⁺in

1‚CH₂Cl₂. Ellipsoids are drawn at the 50% probability level. Hydrogen

atoms are omitted for clarity.

Figure 2. Molecular structure of the cation [Rh(COD)(PPh₂CtCPh)₂]⁺

in 2. Ellipsoids are drawn at the 50% probability level. Hydrogen atoms

are omitted for clarity.

(δ(C_â) 109.4) but move slightly upfield in complex 1 and

downfield in the rest of complexes. The resulting chemical

shift difference [∆(δ(C_â) - δ(C_R))], which can be related to

the triple bond polarization,^15,16,57is similar in neutral Pt(II)

(30, 6; 26.6, 7) or cationic [Rh(I), 28.3, or Ir(I), 28.6]

complexes, being greatest in the cationic tris(phosphine) Pt-

(II) complex 1 (∆ 29.4 for CtC trans to C₆F₅and 33.6 ppm

for the equivalent CtC fragments cis to C₆F₅).

Although phosphinoalkyne mononuclear complexes of

group 10 metals have been known for more than 30 years,

very few of them have been structurally characterized.^2,27,28,43

Details of the crystallographic determinations for 1, 2, and

7‚CH₃COCH₃are presented in Table 1, and selected bond

distances and angles are given in Table 2. The metal centers

in the cations 1⁺and 2⁺and in the neutral complex 7 (Figures

1-3) are located in slightly distorted square-planar environ-

ments with unexceptional bond lengths (M-C, M-P) and

angles for this type of complex.^58,59The Pt-S distances

[2.3052(7) Å] in 7 are within the range of those observed

for other platinum(II) dithiolate phosphine complexes⁶⁰but

longer than those seen in typical platinum diimine dithiolate

derivatives.^61-66

Figure 3. Molecular structure of 7‚CH₃COCH₃. Ellipsoids are drawn at

the 50% probability level. Hydrogen atoms are omitted for clarity.

The P-C(alkyne) and C_R≡C_âbond lengths are slightly

shorter in the rhodium complex 2 [P-C_R1.694(3), 1.673(3)

Å; C_R≡C_â1.168(4), 1.152(4) Å] than in the platinum

derivatives 1 [1.744(4)-1.750(4) Å; 1.199(6)-1.201(6) Å]

and 7 [1.759(3) Å; 1.199(4) Å]. The two cis-alkynyl entities

in these complexes [P(3) and P(2) on 1] are found staggered,

with torsional angles C_R-P-P′-C_R′of 68.6° [C(1)-P(3)-

P(2)-C(21)] (1), 68.5° (2), and 66.3° (7) and dihedral angles

between both P-C_R-C_â-C_γfragments of 38.80° [P(3)-

C(1)-C(2)-C(3) and P(2)-C(21)-C(22)-C(23)] (1), 56.83°

(2), and 124.60° (7). The separation between the alkyne C_R-

C_Ratoms [3.226 Å C(1)-C(21) (1), 3.403 Å (2), and 3.166

Å (7)] is in keeping with the distances observed in previous

square-planar cis-bis(diphenyl)(alkynylphosphine)platinum-

(II) complexes, in which intramolecular coupling of phos-

phinoalkyne ligands was induced by heating^27,28or by metal

complexation.^42,43,67-69As can be observed in Figure 1, in

the cation 1⁺, the mutually trans P(3) and P(1) P-C≡CR

(56) Fornie´s, J.; Garc´ıa, A.; Go´mez, J.; Lalinde, E.; Moreno, M. T.

Organometallics 2002, 21, 3733.

(57) Louattani, E.; LLedo´s, A.; Suades, J.; Alvarez-Larena, A.; Piniella, J.

F. Organometallics 1995, 14, 1053.

(58) Ara, I.; Berenguer, J. R.; Eguiza´bal, E.; Fornie´s, J.; Lalinde, E.;

Mart´ınez, F. Organometallics 1999, 18, 4344.

(59) Ara, I.; Berenguer, J. R.; Fornie´s, J.; Lalinde, E. Organometallics 1997,

16, 3921.

(60) Bevilacqua, J. M.; Zuleta, J. A.; Eisenberg, R. Inorg. Chem. 1994,

33, 258.

(61) Connick, W. B.; Gray, H. B. J. Am. Chem. Soc. 1997, 119, 11620.

(62) Geary, E. A. M.; Hirata, N.; Clifford, J.; Durrant, J. R.; Parsons, S.;

Dawson, A.; Yellowlees, L. J.; Robertson, N. Dalton Trans. 2003,

3757.

(63) Smucker, B. W.; Hudson, J. M.; Omary, M. A.; Dunbar, K. R. Inorg.

Chem. 2003, 42, 4714.

(64) Bevilacqua, J. M.; Eisenberg, R. Inorg. Chem. 1994, 33, 2913.

(65) Keefer, C. E.; Bereman, R. D.; Purrington, S. T.; Knight, B. W.; Boyle,

P. D. Inorg. Chem. 1999, 38, 2294.

(66) Adams, C. J. J. Chem. Soc., Dalton Trans. 2002, 1545.

8192 Inorganic Chemistry, Vol. 43, No. 25, 2004

Alkynyldiphenylphosphine d⁸(Pt, Rh, Ir) Complexes

Scheme 2

fragments are eclipsed and, curiously, this final disposition

favors the presence of π-stacking interactions involving the

C₆F₅ligand and the C(9-14) and C(55-60) phenyl rings,

the averages of the centroid-centroid distances being 3.495

and 3.905 Å, respectively. It has been previously noted that

C₆H₅/C₆F₅π interactions are attractive and a driving force

in many crystallizations.⁷⁰

¹⁹F NMR spectrum confirms the presence of a static and

typical organic C-C₆F₅group, with the ortho (δ -122.1,

-133.3) and para (-153.3) fluorine resonances up- and

downfield shifted, respectively, relative to the resonances in

cis-[Pt(C₆F₅)₂(THF)₂] (the meta fluorine resonances over-

lapped with the other F_metasignals). The rest of the spectrum

is in agreement with the presence of two nonequivalent but

free rotating C₆F₅ligands. Furthermore, its ³¹P NMR

spectrum exhibits the expected ABM spin system with Pt

satellites. The low-frequency signal [dd, J(P¹-P³) ) 362,

J(P¹-P²) ) 14 Hz], close to the value shown in the precursor

(δ -5.9, 8, vs -6.3, 1), is assigned to the terminal

PPh₂C≡CPh ligand (P¹). The most deshielded signal (δ 32.4),

which appears as a broad singlet, due to long-range unre-

solved coupling to the F_oatoms of the mutually trans C₆F₅

group, and is flanked by one set of platinum satellites [¹J(Pt-

P²) ) 2214 Hz], is assigned to phosphorus P²(trans to C₆F₅).

The resonance at δ 28.2 appears as a doublet of doublets

[J(P³-P¹) ) 362 Hz, J(P³-P²) ) 14.3 Hz] and exhibits two

sets of platinum satellites [¹J(P³-Pt) ) 2428 Hz, ²J(P³-Pt)

) 530 Hz] being therefore assigned to the phosphorus P³

Reactions of Mononuclear Complexes with cis-[Pt-

(C₆F₅)₂(THF)₂]. With the aim of extending the insertion

process described in the Introduction to other systems, we

have examined the reactivity of the mononuclear P-coordi-

nated alkynylphosphine complexes 1-3, 6, and 7 toward cis-

[Pt(C₆F₅)₂(THF)₂]. As is shown in Schemes 2-4, the results

depend on the mononuclear substrate employed. The cationic

complex [Pt(C₆F₅)(PPh₂C≡CPh)₃](CF₃SO₃), 1, reacts with

1 equiv of cis-[Pt(C₆F₅)₂(THF)₂] in CH₂Cl₂at room temper-

ature to immediately give an orange solution, from which

the double inserted cationic product [Pt(C₆F₅)(S)-µ-{C(Ph)d

C(PPh₂)C(PPh₂)dC(Ph)(C₆F₅)}Pt(C₆F₅)(PPh₂CtCPh)](CF₃-

SO₃), 8, is isolated as an orange solid in moderate yield

(Scheme 2i). Although the solid-state crystal structure of

crystals obtained by slow diffusion of n-hexane into a THF

solution of 8 reveals that the complex crystallizes with 3

molecules of THF and that the vacant site created by the

insertion process is occupied by a H₂O molecule, the bulk

material and repeated elemental analysis was in keeping with

the presence of 0.5 molecules of THF and 0.5 of H₂O. It

should be noted that when the reaction is monitored by NMR

spectroscopy at low temperature from -50 to -10 °C, no

intermediates are detected and the product 8 is still not

formed. The formation of inserted derivative 8 occurs initially

at 0 °C, and at 20 °C the reaction is complete. The presence

of the C-C₆F₅unit is confirmed by IR (split bands at ∼1500

and ∼990 cm^-1)^43,71,72and ¹⁹F NMR spectroscopy. Thus, the

1

mutually trans to P¹and to the second Pt center. The H

NMR spectrum shows the presence of H₂O coordinated (δ

1.7 broad), which disappear after the addition of D₂O, and

signals due to THF (3.71 s, br, OCH₂; 1.82 s, br, CH₂),

suggesting that both solvents compete for the vacant

coordination site. Crystals obtained by slow diffusion (-30

°C) of n-hexane into a THF solution of the complex were

suitable for X-ray crystallography (Figure 4 and Tables1 and

3). As can be seen, the 2,3-bis(diphenylphosphanyl)butadi-

enyl ligand, formed by condensation of two of the three

acetylenic fragments of the cationic complex 1 with one of

the C₆F₅groups of cis-[Pt(C₆F₅)₂(THF)₂], bridges the two

platinum centers. The structural disposition is essentially

similar to that previously described by us in the neutral

complex [Pt(C₆F₅)µ-1κC¹(3,4)η:2κ²PP′{C(tBu)dC(PPh₂)-

C(PPh₂)dC(Tol)(C₆F₅)}Pt(C₆F₅)₂],⁴³with the ligand display-

(67) Warner, B. P.; Millar, S. P.; Broene, R. D.; Buchwald, S. L. Science

1995, 269, 814.

(68) Coalter, N. L.; Concolino, T. E.; Streib, W. E.; Hughes, C. G.;

Rheingold, A. L.; Zaleski, J. M. J. Am. Chem. Soc. 2000, 122, 3112.

(69) Schmitt, E. W.; Huffman, J. C.; Zaleski, J. M. Chem. Commun. 2001,

167.

(71) Uso´n, R.; Fornie´s, J.; Espinet, P.; Lalinde, E.; Jones, P. G.; Sheldrick,

G. M. J. Chem. Soc., Dalton Trans. 1982, 2389.

(70) Bauer, E. B.; Hampel, F.; Gladysz, J. A. Organometallics 2003, 22,

5567 and references given therein.

(72) Uso´n, R.; Fornie´s, J.; Espinet, P.; Lalinde, E.; Jones, P. G.; Sheldrick,

G. M. J. Organomet. Chem. 1983, 253, C47.

Inorganic Chemistry, Vol. 43, No. 25, 2004 8193

Berenguer et al.

butadienyl ligand [torsional angle C(42)-C(41)-C(40)-

C(39) 60.1°] fall within the expected range.^42,43The dihedral

angle between Pt(2)-C(39)-C(40) and Pt(2)-C(42)-C(61)

is 58.13°. It is noteworthy that the olefinic CdC(C₆F₅)Ph

fragment is located at the same side as the terminal

alkynylphosphine, and this indicates that the reaction is again

regiospecific with the first insertion taking place in 1 with

the PPh₂CtCPh ligand trans to the C₆F₅group. Curiously,

this acetylenic fragment exhibits the most shielded C_â

resonance (δ 109.9 vs 111.5 in PPh₂CtCPh cis to C₆F₅)

δ-

δ+

and also the least polarized alkyne fragment (M-PC_R≡C_â

-

Ph, ∆C_â-C_R29.4 vs 33.6). Another feature of the insertion

process is that an overall stereoselective cis, cis diinsertion

process has taken place, with the PPh₂and Ph groups

mutually cis in the vinyl unit and in the η²-alkene fragment.

Both cis, trans⁷⁴and cis, cis^75-78diinsertion acetylenic

processes have been previously described. In our system,

the final cis, cis stereoselectivity could be attributed to the

simultaneous coordination of both phosphorus atoms to the

cationic “Pt(C₆F₅)(PPh₂CtCPh)⁺” unit.

Figure 4. View of the molecular structure of the cation [Pt(C₆F₅)(OH₂)µ-

{C(Ph)dC(PPh₂)C(PPh₂)dC(Ph)(C₆F₅)}Pt(C₆F₅)(PPh₂CtCPh)]⁺in 8 show-

ing the connectivity of the atoms.

Table 3. Selected Bond Lengths (Å) and Angles (deg) for

[Pt(C₆F₅)(OH₂)µ-{C(Ph)dC(PPh₂)C(PPh₂)dC(Ph)(C₆F₅)}-

Pt(C₆F₅)(PPh₂CtCPh)](CF₃SO₃)‚3THF, 8‚3THF

As is shown in Scheme 2ii, complex 8 is unstable giving

on standing in CH₂Cl₂solution at room temperature for ca.

50 h a very dark solution from which a novel cationic

naphthalene-based diphenylphosphine mononuclear com-

plex [(C₆F₅)(PPh₂CtCPh)Pt{C₁₀H₄-1-C₆F₅-4-Ph-2,3-κPP′-

(PPh₂)₂}](CF₃SO₃), 9, is isolated. The formation of the

1-pentafluorophenyl-2,3-bis(diphenylphosphine)-4-phenyl-

naphthalene ligand has been previously observed by us in

related neutral diinserted complexes.⁴³As commented in the

Introduction, mononuclear complexes containing the asym-

metric naphthalene diphenylphosphine [C₁₀H₅-1-Ph-2,3-κPP′-

(PPh₂)₂] have been also previously reported by Carty et al.^27,28

However, the coupling reactions were only observed under

very drastic conditions (reflux benzene). An easier coupling

reaction (room temperature) has been recently found in a

cyclic trimer of a neutral Pt-bis(alkynyldiphosphine)-

complex.²The ¹⁹F NMR spectrum of 9 confirms the presence

of only two different sets of resonances, one of them

corresponding to a C-C₆F₅organic entity, and the ³¹P{¹H}

NMR spectrum displays the expected ABM system with

platinum satellites [δ(P²) 48.3 (br), δ(P³) 43.1 (dd), δ(P¹)

-5.5 (dd), J(P¹-P³) ) 364 Hz]. However, from the NMR

data it cannot be unambiguously determined whether the

C-C₆F₅group is in position 1 (syn to the terminal PPh₂Ct

CPh ligand) or in position 4 (anti to the PPh₂CtCPh ligand).

It is immediately apparent from the X-ray diffraction study

of 9 that the C-C₆F₅and the terminal PPh₂CtCPh ligand

are located mutually syn (Figure 5, Tables 1 and 4). The

platinum center exhibits the expected square planar geometry

with the phosphorus atoms [P(2), P(3)] of the formed

1-(pentafluorophenyl)-2,3-bis(diphenylphosphine)-4-phenyl-

naphthalene ligand slightly displaced (0.016 and -0.022 Å)

Pt(1)-C(1)

Pt(1)-P(3)

Pt(1)-P(2)

Pt(1)-P(1)

Pt(2)-C(42)

Pt(2)-C(61)

Pt(2)-O(1)

Pt(2)-C(40)

Pt(2)-C(39)

Pt(2)-C(41)

2.080(5)

2.3032(16)

2.3189(13)

2.3247(15)

1.950(6)

2.020(6)

2.167(4)

2.283(5)

2.288(6)

2.611(6)

P(1)-C(7)

1.757(6)

1.850(6)

1.809(6)

1.190(8)

1.434(8)

1.490(8)

1.520(8)

1.487(8)

1.372(9)

P(2)-C(40)

P(3)-C(41)

C(7)-C(8)

C(39)-C(40)

C(39)-C(55)

C(39)-C(49)

C(40)-C(41)

C(41)-C(42)

C(1)-Pt(1)-P(3)

P(3)-Pt(1)-P(2)

C(1)-Pt(1)-P(1)

P(2)-Pt(1)-P(1)

89.02(16)

87.07(5)

89.48(16)

94.34(5)

C(8)-C(7)-P(1)

C(7)-C(8)-C(9)

176.1(6)

176.4(7)

C(40)-C(39)-C(55) 126.8(5)

C(55)-C(39)-C(49) 112.1(5)

C(39)-C(40)-C(41) 117.4(5)

C(39)-C(40)-P(2) 131.1(5)

C(41)-C(40)-P(2) 109.3(4)

C(42)-C(41)-C(40) 107.0(5)

C(42)-C(41)-P(3) 131.8(5)

C(40)-C(41)-P(3) 120.4(4)

C(41)-C(42)-C(43) 127.4(6)

C(41)-C(42)-Pt(2) 102.2(4)

C(43)-C(42)-Pt(2) 130.3(5)

C(42)-Pt(2)-C(61) 95.6(3)

C(61)-Pt(2)-O(1) 85.7(3)

C(42)-Pt(2)-C(40) 65.3(2)

C(61)-Pt(2)-C(40) 155.4(2)

C(42)-Pt(2)-C(39) 84.4(2)

C(61)-Pt(2)-C(39) 163.7(3)

C(40)-Pt(2)-C(39) 36.56(19)

C(40)-Pt(2)-Pt(1) 106.20(18)

C(41)-P(3)-Pt(1) 105.4(2)

ing a µ-1κC¹(3,4)η:2κ²PP′ bonding mode and acting as a

vinylolefin (σ-η²) ligand to the Pt(2)(C₆F₅)(H₂O) unit. Thus,

Pt(2) coordinates to the C_ipsoof the C₆F₅group and the

butadienyl backbone, which is σ-bonded through C(42) and

η²-bonded through the C(39)-C(40) double bond. The vacant

position, generated by the insertion process, is completed

with a molecule of H₂O. The Pt-O distance [Pt-O 2.167-

(4) Å] is comparable to that found in the binuclear complex

[Pt₂(H₂O)₂Ph₂(ttab)](BAr₄)₂(ttab ) 1,2,4,5-tetrakis(1-N-7-

azaindolyl)benzene, Ar ) 3,5-bis(trifluoromethyl)phenyl,

2.098(8) Å),⁷³and the Pt-C(vinyl) bond length [Pt(2)-C(42)

1.950(6) Å] is rather short in agreement with the low trans

influence of the oxygen donor ligand. The η²-olefin interac-

tion [Pt(2)-C(39),C(40) 2.288(6), 2.283(5) Å] and the

interatomic distances [C(39)-C(40) 1.434(8), C(40)-C(41)

1.487(8), C(41)-C(42) 1.372(9) Å] and angles about the

(74) Pfeffer, M. Pure Appl. Chem. 1992, 64, 335.

(75) Yagyu, T.; Hamada, M.; Osakada, K.; Yamamoto, T. Organometallics

2001, 20, 1087 and references therein.

(76) Vicente, J.; Abad, J. A.; Ferna´ndez de Bobadilla, R.; Jones, P. G.;

Ram´ırez de Arellano, M. C. Organometallics 1996, 15, 24.

(77) Maitlis, P. M. J. Organomet. Chem. 1980, 200, 161.

(78) Kelley, E. A.; Maitlis, P. M. J. Chem. Soc., Dalton Trans. 1979, 167.

(73) Song, D.; Jia, W. L.; Wang, S. Organometallics 2004, 23, 1194.

8194 Inorganic Chemistry, Vol. 43, No. 25, 2004

Alkynyldiphenylphosphine d⁸(Pt, Rh, Ir) Complexes

Table 4. Selected Bond Lengths (Å) and Angles (deg) for

[(C₆F₅)(PPh₂CtCPh)Pt{C₁₀H₄-1-C₆F₅-4-Ph-2,3-κPP′(PPh₂)₂}]-

(CF₃SO₃)‚2CH₂Cl₂, 9‚2CH₂Cl₂

Pt(1)-C(21)

Pt(1)-P(3)

Pt(1)-P(2)

Pt(1)-P(1)

P(2)-C(51)

P(3)-C(52)

C(1)-C(2)

C(51)-C(60)

2.089(7)

C(51)-C(52)

C(52)-C(53)

C(53)-C(54)

C(53)-C(67)

C(54)-C(59)

C(59)-C(60)

C(60)-C(61)

1.432(9)

2.2905(19)

2.2940(18)

2.3333(19)

1.861(7)

1.829(7)

1.193(10)

1.369(10)

1.384(10)

1.433(10)

1.508(10)

1.424(10)

1.435(10)

1.513(9)

C(21)-Pt(1)-P(3) 92.3(2)

P(3)-Pt(1)-P(2) 84.73(6)

C(21)-Pt(1)-P(1) 87.4(2)

P(2)-Pt(1)-P(1) 95.57(6)

C(51)-P(2)-Pt(1)

C(52)-P(3)-Pt(1)

108.4(2)

108.8(2)

C(52)-C(53)-C(67) 123.3(7)

C(51)-C(60)-C(61) 123.7(6)

Pt(µ-κO:η²-PPh₂(O)CtCPh)]₂, 10, are obtained together with

a dark oil (Scheme 3). The NMR spectrum of the dark oil

reveals the presence of a very impure inserted product (see

Experimental Section for details). As was expected, complex

10 is alternatively obtained by reaction of cis-[Pt(C₆F₅)₂-

(THF)₂] with 1 equiv of PPh₂(O)CtCPh. The insolubility

of this complex (10) precludes its characterization by NMR

spectroscopy in solution. However, its IR spectrum reveals

the presence of only one ν(CtC) signal (1981 cm^-1) and

the appearance of a new band in the PdO stretching region

(1165 cm^-1) at lower frequencies than those observed in

PPh₂(O)CtCPh [ν(CtC) 2173, 2156 cm^-1; ν(PdO) 1194

cm^-1], in accordance with the presence of an acetylenic

phosphine oxide coordinated through the oxygen atom and

the acetylenic fragment.^9,79,80

Figure 5. Molecular structure of the cation [(C₆F₅)(PPh₂CtCPh)Pt{C₁₀H₄-

1-C₆F₅-4-Ph-2,3-κPP′(PPh₂)₂}]⁺in 9 with thermal ellipsoids at the 50%

probability level. Hydrogen atoms are omitted for clarity.

from that plane. The bond lengths are in the expected range,

and the slight deviation of the angles from a perfect square-

planar geometry can be explained by steric effects of the

chelating ligand. The naphthalene ring is also planar, and

the dihedral angle with the platinum coordination plane is

only 18.80°.

Attempts to stabilize analogous Rh-Pt or Ir-Pt insertion

products were unsuccessful. Thus, NMR (³¹P and ¹⁹F)

monitoring of the reaction of [Rh(COD)(PPh₂CtCPh)₂]-

(ClO₄), 2, with 1 equiv of cis-[Pt(C₆F₅)₂(THF)₂] in CDCl₃

indicates the presence of a complex mixture, in which

unknown insertion products (C-C₆F₅), cis-[Pt(C₆F₅)₂(PPh₂Ct

CPh)₂], and starting material (2) could be detected after 10

min and even 8 h of reaction. The formation of cis-[Pt(C₆F₅)₂-

(PPh₂CtCPh)₂] clearly indicates that the migration of

phosphine ligands between electronically different metal

centers competes with the insertion process. Unfortunately,

the low stability of the insertion product precluded its

isolation. On the other hand, when a mixture of cis-[Pt-

(C₆F₅)₂(THF)₂] and [Ir(COD)(PPh₂CtCPh)₂](ClO₄), 3 (1:1

molar ratio), in CH₂Cl₂at -30 °C is layered with n-hexane

and kept at -30 °C for 1 week, white crystals of a new

complex, characterized by X-ray crystallography as [(C₆F₅)₂-

As is shown in Figure 6 (see Tables 1 and 5), the two

“Pt(C₆F₅)₂” moieties in 10 are related by an inversion center

and connected by two alkynylphosphine oxides (Pt‚‚‚‚Pt

5.002 Å) which are coordinated acting as 1κO:2η²bridging

ligands. In the resulting central eight-membered dimetalla-

cycle, the atoms C(1^a)-P(1)-O(1) and C(1)-P(1^a)-O(1^a)

are nearly coplanar [maximum deviation 0.099 Å, P(1)] with

the platinum atoms [Pt(1), Pt(1^a)] down and up (1.327 Å),

respectively, from this plane. The η²-platinum-acetylenic

linkage is asymmetric with the Pt-C_Rdistance [2.167(4) Å]

slightly shorter than the corresponding Pt-C_âbond distance

[2.224(4) Å], and the P-C_R-C_â-C_γskeleton shows a

marked deviation from linearity [P(1^a)-C(1)-C(2) 158.4-

(4)°, C(1)-C(2)-C(3) 164.1(4)°]. The P-C(1^a) [1.763(5)

Å] and the P-O [1.496(3) Å] bond lengths and the O-P-C

Scheme 3

Inorganic Chemistry, Vol. 43, No. 25, 2004 8195

Berenguer et al.

(BF₄) was oxidized to an iron vinyldiphenylphosphine oxide⁸¹

and the η²-alkynylphosphine complex [Pt(η²-PPh₂CtCMe)-

(dcpe)] was oxidized in air to the corresponding phosphine

oxide complex [Pt{η²-PPh₂(O)CtCMe}(dcpe)].⁹

To check the possibilities of insertion in other systems,

we have examined the reactions of the catecholate and

dithiolate complexes 6 and 7 with cis-[Pt(C₆F₅)₂(THF)₂] in

1:1 and 1:2 molar ratios. However, the ability of these ligands

(catecholate, dithiolate, and alkynylphosphine) to bridge

metal atoms leads, in this case, to the formation of stable

homo- bi- or trimetallic complexes containing mixed bridges

µ-(o-C₆H₄E₂)/µ-PPh₂CtCPh systems (E ) O, S) (Scheme

4). Reactions of [Pt(o-C₆H₄E₂)(PPh₂CtCPh)₂] (E ) O, 6,

and S, 7) with 1 equiv of cis-[Pt(C₆F₅)₂(THF)₂] in CH₂Cl₂

yield bimetallic derivatives [Pt(PPh₂CtCPh)(µ-κE-o-C₆H₄E₂)-

(µ-κP:η²-PPh₂CtCPh)Pt(C₆F₅)₂] (E ) O, 11, and S, 12) as

yellow-brown (11) or grayish (12) solids in high or moderate

yields. Similar reactions with 2 equiv of cis-[Pt(C₆F₅)₂-

(THF)₂] afford the trimetallic complexes [{Pt(µ₃-κ²EE′-o-

C₆H₄E₂)(µ-κP:η²-PPh₂CtCPh)₂}{Pt(C₆F₅)₂}₂] (E ) O, 13,

and S, 14) as a white 13 (80%) or brown 14 (93%) solid,

respectively. The dimetallic or trimetallic formulation with

the mixed heterobridged (µ-κE-o-C₆H₄E₂)/(µ-κP:η²-PPh₂Ct

CPh) or (µ₃-κ²EE′-o-C₆H₄E₂)/(µ-κP:η²-PPh₂CtCPh)₂sys-

tems has been established by elemental analysis and spec-

troscopic data and confirmed by an X-ray diffraction study

on complex 14. The presence of terminal and bridging

alkynylphosphine groups in these complexes is inferred from

the IR and NMR data. The binuclear complexes (11, 12)

display one broad ν(CtC) absorption, corresponding to the

bridging ligand (1968 cm^-1, 11; 1975 cm^-1, 12), and another

sharp one due to the terminal ligand (2175 cm^-1, 11; 2174

cm^-1, 12). By contrast, the trimetallic complexes 13 and 14

contain only one ν(CtC) broad band in the characteristic

region of κP:η²bridging PPh₂CtCR ligands (1968 cm^-1,

13; 1978 cm^-1, 14). Two different phosphorus resonances

(AX systems) are seen in the ³¹P{¹H} NMR spectra of the

binuclear complexes, confirming the inequivalence of both

PPh₂CtCPh ligands. The low-field resonance (δ -2.7, 11,

and 5.0, 12), significantly deshielded in relation to the

Figure 6. View of the molecular structure of the complex [(C₆F₅)₂Pt(µ-

κO:η²-PPh₂(O)CtCPh)]₂, 10, showing the atom-numbering scheme.

Table 5. Selected Bond Lengths (Å) and Angles (deg) for

[(C₆F₅)₂Pt(µ-κO:η²-PPh₂(O)CtCPh)]₂‚1.5CH₂Cl₂, 10‚1.5CH₂Cl₂

Pt(1)-C(21)

Pt(1)-C(27)

Pt(1)-O(1)

Pt(1)-C(1)

Pt(1)-C(2)

1.979(4)

2.032(4)

2.111(3)

2.167(4)

2.224(4)

P(1)-O(1)

P(1)-C(1^a)

C(1)-C(2)

C(2)-C(3)

1.496(3)

1.763(5)

1.238(6)

1.434(6)

C(21)-Pt(1)-C(27) 88.28(18)

O(1)-P(1)-C(1^a) 111.4(2)

P(1)-O(1)-Pt(1) 148.9(2)

C(2)-C(1)-P(1^a) 158.4(4)

C(27)-Pt(1)-O(1)

C(21)-Pt(1)-C(1)

O(1)-Pt(1)-C(1)

C(21)-Pt(1)-C(2)

O(1)-Pt(1)-C(2)

91.96(15)

92.75(17)

88.86(15)

96.22(17)

82.40(14)

C(2)-C(1)-Pt(1)

C(1)-C(2)-C(3)

C(1)-C(2)-Pt(1)

76.2(3)

164.1(4)

71.1(3)

angle [111.4(2)°] are in the range of those observed in

coordinated alkynylphosphine oxides.^9,79,80

The unexpected formation of an alkynylphosphine oxide

complex starting from the corresponding alkynylphosphine

ligand has been previously reported. For example, [(η⁵-

C₅H₅)Ni]₂(PPh₂(O)C₂CF₃), the first acetylenic phosphine

oxide π complex structurally characterized, was obtained as

one byproduct in the reaction of [(η⁵-C₅H₅)₂Ni] with PPh₂Ct

CCF₃.⁷⁹More recently, a cationic iron P-coordinated (diphe-

nylphosphino)alkyne complex [(C₅H₅)Fe(CO)₂(PPh₂CtCPh)]-

Scheme 4

8196 Inorganic Chemistry, Vol. 43, No. 25, 2004

Alkynyldiphenylphosphine d⁸(Pt, Rh, Ir) Complexes

Table 6. Selected Bond Lengths (Å) and Angles (deg) for

[{Pt(µ-κ²S,S′-o-C₆H₄S₂)(µ-κP:η²-PPh₂CtCPh)₂}{Pt(C₆F₅)₂}₂], 14

Pt(1)-P(2)

Pt(1)-P(1)

Pt(1)-S(1)

Pt(1)-S(2)

Pt(2)-C(47)

Pt(2)-C(53)

Pt(2)-C(21)

Pt(2)-C(22)

Pt(2)-S(2)

Pt(3)-C(59)

Pt(3)-C(65)

2.2799(19) Pt(3)-C(1)

2.2853(16) Pt(3)-C(2)

2.3237(18) Pt(3)-S(1)

2.3307(16) S(1)-C(41)

2.208(7)

2.242(6)

2.3864(16)

1.772(7)

1.762(9)

1.772(7)

1.768(7)

1.234(10)

1.238(9)

1.401(11)

2.042(9)

2.044(7)

2.198(7)

2.250(7)

S(2)-C(46)

P(1)-C(1)

P(2)-C(21)

C(1)-C(2)

2.3854(17) C(21)-C(22)

2.031(7)

2.052(7)

C(41)-C(46)

P(2)-Pt(1)-P(1)

P(1)-Pt(1)-S(1)

P(2)-Pt(1)-S(2)

S(1)-Pt(1)-S(2)

C(47)-Pt(2)-C(53) 86.4(3)

C(53)-Pt(2)-C(21) 101.6(3)

C(53)-Pt(2)-C(22) 90.3(3)

C(47)-Pt(2)-S(2)

C(21)-Pt(2)-S(2)

C(22)-Pt(2)-S(2)

C(59)-Pt(3)-C(65) 86.4(3)

C(65)-Pt(3)-C(1) 102.1(3)

C(65)-Pt(3)-C(2) 91.1(3)

C(59)-Pt(3)-S(1)

C(1)-Pt(3)-S(1)

98.88(7)

86.25(6)

87.19(7)

88.24(7)

C(2)-Pt(3)-S(1)

88.41(17)

C(41)-S(1)-Pt(1) 104.9(3)

C(41)-S(1)-Pt(3) 110.0(2)

Pt(1)-S(1)-Pt(3)

C(46)-S(2)-Pt(1) 104.1(3)

C(46)-S(2)-Pt(2) 110.0(3)

94.56(6)

Figure 7. Molecular structure of [{Pt(µ₃-κ²S,S′-o-C₆H₄S₂)(µ-κP:η²-

PPh₂CtCPh)₂}{Pt(C₆F₅)₂}₂], 14, showing the atom-numbering scheme.

Pt(1)-S(2)-Pt(2)

C(2)-C(1)-P(1)

C(1)-C(2)-C(3)

C(22)-C(21)-P(2) 153.3(6)

C(21)-C(22)-C(23) 164.5(8)

C(42)-C(41)-S(1) 120.2(6)

C(46)-C(41)-S(1) 120.2(6)

C(41)-C(46)-S(2) 122.4(6)

C(45)-C(46)-S(2) 119.3(7)

96.76(6)

156.2(6)

162.0(7)

93.1(2)

78.88(18)

90.17(18)

corresponding precursors (δ -14.5, 6, and -4.7, 7), is

attributed to the P atom of the bridging µ-κP:η²-PPh₂Ct

CPh, and the high-field signal (δ -24.8, 11, and -13.5, 12)

is, therefore, assigned to the terminal P-coordinated ligand.

As expected, a singlet phosphorus resonance (δ(P) -10.7,

13, and -1.2, 14) with ¹⁹⁵Pt satellites is observed in the

trinuclear complexes (13, 14). In agreement with the

formulations shown in Scheme 4, the ¹⁹F NMR spectra reveal

the presence of two nonequivalent and freely rotating C₆F₅

groups (AA′MXX′ systems trans to CtC and trans to S)

except complex 11 in which one of the rings is rigid on the

NMR time scale (see Experimental Section for details). The

aromatic protons of C₆H₄E₂groups are seen as two sym-

metric multiplets in 13 and 14 (δ 6.76/6.32, 13, and 7.14/

6.85, 14), while the more asymmetric binuclear complexes

11 and 12 give rise to one doublet (2H) and two triplets

(1:1 H:H).

The structure of 14 is shown in Figure 7 (relevant data

are summarized in Tables 1 and 6). In this complex, the bis-

[(diphenylphenylethynyl)phosphine] precursor 7 acts as

mixed bis(thiolate/η²-alkyne) tetradentate ligand toward two

“cis-Pt(C₆F₅)₂” fragments in a such way that the thiolate

ligand exhibits a simultaneous chelating and bridging bond-

ing mode. The two sulfur atoms are chelating the Pt(1) atom

and bridging the Pt(2) and Pt(3) centers, resulting in an

homotrinuclear Pt₃assembly with the thiolate ligand coor-

dinated to the three platinum atoms in µ₃-κSS′ form. Very

few structural examples containing a benzenedithiolate ligand

acting as µ₃-κSS′ bridging are presently known.^82-90To our

knowledge, this complex (14) represents the first trimetallic

93.7(2)

78.15(17)

compound in which three metals are linked together by two

mixed thiolate/η²-alkynylphosphine bridging systems. The

dihedral angles between the best square plane around each

platinum center are Pt(1) plane-Pt(2) plane 75.72°, Pt(1)

plane-Pt(3) 79.07°, and Pt(2) plane-Pt(3) 75.05°. The µ₃-

bridging thiolate ligand is nearly planar [dihedral angle

between Pt(1)-S₂and S₂C₆H₄planes is 2.67(0.18)°] and

adopts an anti conformation, with the platinum atoms, Pt

(3) and Pt(2), located down (-2.0620 Å) and up (2.0057 Å)

the Pt(1) coordination plane. The sulfur-platinum bond

lengths are, as expected, slightly greater than that seen in 7.

The Pt(2,3)-C(acetylenic) bond distances [2.198(7)-2.250-

(7) Å] and the distortion from linearity of the acetylenic

fragments are within the expected range. The platinum-

platinum distances exclude any bonding interactions [Pt(1)-

Pt(3) 3.461 Å and Pt(2)-Pt(1) 3.526 Å].

The cyclic voltammetric behavior of the catecholate and

dithiolate complexes (6, 7, 11-14) has been examined, and

the results are summarized in Table 7. The mononuclear

complexes 6 and 7 exhibit two oxidation one-electron-

transfer waves, which, with reference to previous studies,^91-94

are tentatively attributed to ligand-based successive oxida-

tions of the aromatic dianions (L)^2-to the semiquinonate

radical anions (L•)^-and further to the quinones (L)⁰. For

the catecholate mononuclear complex 6, the first oxidation

wave is reversible (∆E ) 222 mV, i_c/i_a) 1.10) while the

second peak at 0.94 V is irreversible. The dithiolate deriva-

tive 7 only gives two irreversible oxidation waves (0.46 and

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Trans. 1993, 1347.

Inorganic Chemistry, Vol. 43, No. 25, 2004 8197

Berenguer et al.

Table 7. Electrochemical Data^a(V) for Catecholate and Dithiolate

Complexes 6, 7, and 11-14

of these compounds toward the labile solvento species cis-

[Pt(C₆F₅)₂(THF)₂] is strongly influenced by the metal, the

charge, and the ligands. Starting from the cationic tris-

(phosphine)platinum complex 1, its reaction with “cis-Pt-

(C₆F₅)₂” induced a regio- and stereoselective cis, cis-

diinsertion process yielding the binuclear σ,π-butadienyl-

diphosphine bridging complex (8) in which the resulting Pt-

(σ,π-butadienyl)(C₆F₅) fragment is stabilized by a solvent

donor molecule (THF, H₂O). This complex 8 is unstable in

solution decomposing with loss of a PtC₆F₅fragment and

yielding a naphthalene-based diphenylphosphine mono-

nuclear complex 9. However, attempts to stabilize related

cationic heterobinuclear Rh/Pt or Ir/Pt products were unsuc-

cessful primarily due to low stability of the resulting products

and the existence of competing phosphine exchange pro-

cesses. Using the iridium complex 3 as precursor we were

only able to isolate the alkynylphosphine oxide diplatinum

complex 10. By contrast, the catecholate (6) or 1,2-

benzenedithiolate (7) derivatives, which contain additional

potential bridging donor atoms (O, S), react with the cis-

[Pt(C₆F₅)₂(THF)₂] complex yielding novel and unprecedented

heterobridged (µ-κE-o-C₆H₄E₂)/(µ-κP:η²-PPh₂CtCPh) bi-

nuclear complexes 11 and 12 or (µ₃-κ²EE′-o-C₆H₄E₂)/(µ-κP:

η²-PPh₂CtCPh)₂trinuclear species 13 and 14. The formation

of complexes 11 and 12 indicates that the η²-bonding

capability of PPh₂CtCPh competes efficiently with the

donor ability of the O or S atoms, since more symmetric

binuclear species with both oxygen or sulfur acting as

bridging centers could have been formed.

1

2

compd

E_pa

6

7

11

12

13

14

-0.06^b(r)

0.46 (irr)

0.39 (qirr)

0.36 (irr)

0.28 (irr)

-

0.94 (irr)

0.97 (irr)

0.94 (irr)

0.83 (irr)

0.94 (irr)

-

^aMeasured in CH₂Cl₂(0.1 M (NBu₄)(PF₆) vs Fc/Fc⁺at 20 °C and a

scan rate of 200 mV s^-1). r ) reversible, irr ) irreversible, and qirr )

b

quasiirreversible. E_1/2of reversible process.

0.97 V). The binuclear and trinuclear catecholate derivatives

11 and 13 also exhibit two anodic responses. The first anodic

peak in 11 is quasiirreversible while the remaining responses

are only poorly defined irreversible patterns. In both com-

plexes, the first wave is anodically shifted (∆ 0.45 V, 11,

and 0.34 V, 13) compared to the precursor which is consistent

with the relative electron deficiency of the bridging catecho-

late ligand upon coordination to the “Pt(C₆F₅)₂” units. In

contrast to this behavior, the trinuclear dithiolate complex

does not give any anodic response and the binuclear

derivative 12 shows a small feature at 0.36 V followed by a

clear one-electron oxidation irreversible wave centered at

0.83 V.

Conclusions

In summary, we report the synthesis and structural

characterization of several cationic or neutral mononuclear

d⁸(Pt, Rh, Ir) P-coordinated alkynylphosphine complexes

1-3, 6, and 7. In these complexes, the ¹³C NMR studies

suggest that the alkyne polarization upon alkyne complex-

ation of PPh₂CtCPh molecules is similar in neutral [Pt(II)]

or cationic [Rh(I), Ir(I)] derivatives. The reactivity pattern

Acknowledgment. This work was supported by the

Spanish Ministerio de Ciencia y Tecnolog´ıa (Project

BQU2002-03997-C02-01, 02) and the Government of La

Rioja (ACPI-2002/08). A.G. wishes to thank the MCYT for

a grant, and M.B. thanks the Government of La Rioja for a

grant.

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Weyhermu¨ller, T.; Wieghardt, K. Angew. Chem., Int. Ed. 2003, 42,

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(93) Pal, S.; Das, D.; Sinha, C.; Kennard, C. H. L. Inorg. Chim. Acta 2001,

313, 21.

Supporting Information Available: Crystallographic data in

CIF format. This material is available free of charge via the Internet

at http://pubs.acs.org.

(94) Rauth, G. K.; Pal, S.; Das, D.; Sinha, C.; Slawin, A. M. Z.; Woollins,

J. D. Polyhedron 2001, 20, 363.

IC048987J

8198 Inorganic Chemistry, Vol. 43, No. 25, 2004

Article Doi

Alkynyldiphenylphosphine d8 (Pt, Rh, Ir) complexes: Contrasting behavior toward cis-[Pt(C6F5)2(THF) 2]

DOI: 10.1021/ic048987j

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Article abstract of DOI:10.1021/ic048987j

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