Synthesis and characterization of cyclometallated palladium(II) and platinum(II) complexes with amide-thiolate ligands

The redox reaction of bis(2-benzamidophenyl) disulfide (H₂L-LH₂) with [Pd(PPh₃)₄] in a 1:1 ratio gave mononuclear and dinuclear palladium(II) complexes with 2-benzamidobenzenethiolate (H₂L⁻), [Pd(H₂L-S)₂(PPh₃)₂] (1) and [Pd₂(H₂L-S)₂ (μ-H₂L-S)₂(PPh₃)₂] (2). A similar reaction with [Pt(PPh₃)₄] produced only the corresponding mononuclear platinum(II) complex, [Pt(H₂L-S)₂(PPh₃)₂] (3). Treatment of these complexes with KOH led to the formation of cyclometallated palladium(II) and platinum(II) complexes, [Pd(L-C,N,S)(PPh₃)]⁻ ([4]⁻) and [Pt(L-C,N,S) (PPh₃)]⁻ ([5]⁻). The molecular structures of 2, 3 and [4]⁻ were determined by X-ray crystallography.     

Enthalpies of reaction of bis(triphenylphosphine)(trans-stilbene)platinum(0) with diphenylcyclopropenone and benzocyclobutenedione

Enthalpies, ΔH(1) ?94.8 ± 6.0 and ΔH(6) ?57.1 ± 5.1 kJ mol^?1, of the following reactions have been measured calorimetrically [Pt(trans-stilbene)(PPh₃)₂](s) + dpcp(g) → (PPh₃)₂Pt(dpcb)(s) + trans-stilbene(g) (1) [Pt(trans-stilbene)(PPh₃)₂](s) + bcbd(g) → (PPh₃)₂Pt(bcpd)(s) + trans-stilbene (g) (6) where dpcp is diphenylcyclopropenone, (PPh₃)₂Pt(dpcb) is (1,1-bistriphenylphosphine)platinadiphenylcyclobutenone, (PPh₃)₂$\text{PtC(Ph)C(Ph)C}$O, bcbd is benzocyclobutene-1,2-dione and (PPh₃)₂Pt(bcpd) is (1,1-bistriphenylphosphine)platinabenzocyclopentanedione,

. It is concluded that the five-membered platinacyclo ring system in (PPh₃)₂Pt(dpcb) is not heavily strained.     

Synthesis of ylideplatinum(II) complexes via α-functionalised alkylplatinum(II) intermediates and some comparative data on palladium(II) complexes; X-ray structure of trans-[Pt(CH2PEt3)I(PEt3)2]I

The reaction of [Pt(PEt₃)₃] with CH₂I₂ affords trans-[Pt(CH₂PEt₃)I(PEt₃)₂]I and is believed to proceed via the α-functionalised alkyl cis-[Pt(CH₂I)I(PEt₃)₂], because similar ylides are obtained from cis- or trans-[PT(CH₂X)(PPh₃)₂X] (XCl, Br, or I) with PR₃ (PEt₃, PBu₃ⁿ, PMePh₂, PEtPh₂, or PPh₃); cis-[Pd(CH₂I)-I(PPh₃)₂] does not react with excess PPh₃, but with PEt₃ yields trans-[Pd(CH₂PEt₃)I(PPh₃)₂]I; the X-ray structure of trans-[Pt(CH₂PEt₃)I(PEt₃)₂]I (current R = 0.045) shows PtP(1) 2.332(7), PtP(2) 2.341(8), PtC 2.08(2), and PtI 2.666(2) Å, and angles (a) C(1)PtI, P(1), P(2): 176.9(8), 91.6(6), 93.4(6), (b) IPtP(1), P(2): 87.1(2), 88.5(2), and (c) P(1)P(2), 166.8(3), and (d) PtC(1)P(3), 118(1)°.     

Synthesis,structure and spectroscopic properties of some thiosemicarbazone complexes of platinum

Reaction of salicyldehyde thosemicarbazone (H₂L¹), 2-hydroxyacetophenone thiosemicarbazone (H₂L²) and 2-hydroxynapthaldehyde thiosemicarbazone (H₂L³) (general abbreviation H₂L, where H₂ stands for the two dissociable protons, one phenolic proton and one hydrazinic proton) with K₂[PtCl₄] afforded a family of polymeric complexes of type [{Pt(L)}_n]. Reaction of the polymeric species with two monodentate ligands (D), viz. triphenylphosphine (PPh₃) and 4-picoline (pic), yielded complexes of the type [Pt(L)(D)]. These mixed-ligand complexes were also obtained from the reaction of the thiosemicarbazones with [Pt(PPh₃)₂Cl₂] and [Pt(pic)₂Cl₂]. The crystal structure of [Pt(PPh₃)(L²)] has been determined. The thiosemicarbazone ligands are coordinated, via dissociation of the two protons, as dianionic tridentate O,N,S-donors. The [Pt(L)(D)] complexes show characteristic ¹H NMR spectra and intense absorptions in the visible and ultraviolet region. They also fluoresce in the visible region at ambient temperature.     

Coordination chemistry of sulfines : I. Synthesis and characterization of the complexes Pt(PPh3)2(XYCSO) (X,Y = aryl,S-aryl,S-alkyl,Cl). Coordination via the CS-π-bond

Reactions of Pt(PPh₃)₄ with the sulfines, XYCSO, (X, Y = aryl, S-aryl, S-alkyl, Cl) yield coordination compounds of the type Pt(PPh₃)₂(XYCSO). Infrared, ³¹P and ¹H NMR spectra reveal that in all cases the sulfine ligand is coordinated side-on via the CS π-bond (Pt—η²-CS). Reactions of Pt(PPh₃)₄ with either the E- or Z-isomer of (p-CH₃C₆H₄)(CH₃S)CSO yields the corresponding E- or Z-coordination compound, Pt(PPh₃)₂[E-(p-CH₃C₆H₄)(CH₃S)CSO] or Pt(PPh₃)₂[Z-(p-CH₃C₆H₄)(CH₃S)CSO], indicating that the configuration of the sulfine ligand is retained upon coordination to the Pt(PPh₃)₂ unit. The compounds Pt(PPh₃)₂(XYCSO), containing reactive CX and/or CY bonds (X, Y = S-aryl, S-alkyl, Cl), undergo a rearrangement in solution to give complexes of the type PtX(PPh₃)₂(YCSO).     

Organoplumbio complexes of platinum(II)

The complex [Pt(C₂H₄)(PPh₃)₂] reacts with Pb₂Ph₆ to give cis-[PtPh(Pb₂Ph₅)(PPh₃)₂]; this decomposes in solution to cis-[PtPh(PbPh₃)(PPh₃)₂], which may also be obtained from the ethylene complex and PbPh₄. Lead compounds PbPhMe₃ and PbPh₃Br also give products of insertion into PbPh bonds, but PbMe₃Cl gives cis- and trans-[PtCl(PbMe₃)(PPh₃)₂]. The complex trans-[Pt(PbPh₃)₂(PEt₃)₂] reacts with 1,2-bis(diphenylphosphino)ethane (DPPE) to give [Pt(PbPh₃)₂(DPPE)] which readily decomposes in dichloromethane in presence of PEt₃ to give [Pt(PbPh₃)(PEt₃)(DPPE)]Cl and [PtPh(PEt₃)(DPPE)]Cl. The complex trans-[PtCl(PbPh₃)(PEt₃)₂] was detected in the products of reactions between trans-[PtCl₂(PEt₃)₂] and trans-[Pt(PbPh₃)₂(PEt₃)₂] or less than 2 moles of LiPbPh₃; it was not detected in the mixture after treatment of trans -[Pt(PbPh₃)₂(PEt₃)₂] with HCl. In contrast to an earlier report, we were unable to detect lead-containing complexes in the products of the reaction between trans-[PtHCl(PPh₃)₂] and Ph₃PbNO₃. The complexes and their decomposition products were identified by ^pre31P-{¹H} NMR spectroscopy.     

The synthesis,characterisation and crystal structure of [Pt3(PPh3)2(CNC6H3Me2)6](PF6)2; a linear trinuclear cluster of platinum

[Pt₂(PPh₃)₂(CN-xylyl)₄]²⁺ (CN-xylyl = 2,6-dimethylphenyl isocyanide) and [Pt₃(PPh₃)₂(CN-xylyl)₆]²⁺ have been synthesized by reaction of [Pt(PPh₃)₂(C₂H₄)] with either [Pt(PPh₃)₂Cl₂] and CN-xylyl or [Pt(CN-xylyl)₄]²⁺. The products have been characterised by ³¹P{¹H} and ¹⁹⁵Pt{¹H} NMR spectroscopy, and a single crystal X-ray diffraction study of the trinuclear compound has demonstrated that the skeletal atoms are linear.     

Haloalkyl complexes of the transition metals: IV. The formation of a cationic ylide complex of platinum(II) from a chloromethylplatinum(II) complex and the crystal structures of cis-[Pt(CH2PPh3)X(PPh3)2]I (X = Cl or I)

The reactions of Pt(PPH₃)₄ and Pt(C₂H₄)(PPh₃)₂ with CH₂ClI have been investigated. The product of the reaction of Pt(PPh₃)₄ with CH₂ClI is the cationic ylide complex cis-[Pt(CH₂PPh₃)Cl(PPh₃)2][I], whereas the reaction of Pt(C₂H₄)-(PPh₃)₂ gives the oxidative addition product Pt(CH₂Cl)I(PPh₃)₂. Reaction of cis- or trans-Pt(CH₂Cl)I(PPh₃)₂] with PPh₃ gives the complex cis-[Pt(CH₂PPh₃)-Cl(PPh₃)₂][I]. The structures of the complexes cis-[Pt(CH₂PPh₃X(PPh₃)₂][I] (where X = Cl or I) have been determined by X-ray crystallography. Both complexes crystalize in the monoclinic space group P2₁/n. For X = Cl a 1388.6(7), b 2026.7(10), c 1823.9(9) pm, β 96.51(2)° and R converged to 0.075 for 3542 observed reflections; structural parameters Pt-Cl 240(1), Pt-C(3) 212(2), Pt-P(2) (trans to Cl) 235(1) and Pt-P(1) (trans to CH₂PPh₃) 233(1) pm; Cl-Pt-C(3) 86.9(5), C(3)-Pt-P(2) 91.8(5), P(2)-Pt-P(1) 97.0(2) and P(1)-Pt-Cl 85.1(2)°. For X = I, a 1379.4(7), b 2044.4(10), c 1840.0(9) pm, β 96.09(2)° and R converged to 0.071 for 4333 observed reflections; structural parameters Pt-I 266(1), Pt-C(3) 212(2), Pt-P(2) (trans to I) 226(1) and Pt-P(1) (trans to CH₂PPh₃ 233(1) pm; I-Pt-C(3) 87.2(5), C(3)-Pt-P(2) 91.5(5), P(2)-Pt-P(1) 96.5(2) and P(1)-Pt-I 85.6(1)°. Some other complexes of the type cis-[Pt(CH₂PPh₃)X(PPh₃)₂]Y are also described.     

Metal catalysed Brooke rearrangement of 3-Halo-1-(trimethylsilyl) propan-2-one (Halo = Cl or Br)

The complexes [IrH(CO)(PPh₃)₃], trans-[IrCI(CO)- (PPh₃)₂], [RhH(PPh₃)₄], [Pd(PPh₃)₄], [Pt(trans-stilbene)(PPh₃)₂] and [Pt(η³-CH₂-COCH₂)-(PPh₃)₂] catalyse the rearrangement of Me₃SiCH₂C(O)CH₂Cl to CH₂?C(OSiMe₃)-CH₂Cl.     

Synthesis and redistribution reactions of asymmetric σ-arylplatinum(II) complexes containing 4,7-phenanthroline

The mononuclear σ-aryl complexes of the type trans-[Pt(σ-C₆H₄R)(4,7-phen)(PPh₃)₂]OTf (R=4-CO₂Si^tBuPh₂, 4-CONHMe, 3-CO₂Si^tBuPh₂, 3-CONHMe; OTf=trifluoromethanesulfonate) containing a monodentate 4,7-phenanthroline (4,7-phen) ligand were prepared by an oxidative addition reaction of an aryl iodide with Pt(PPh₃)₄ to yield the key iodoplatinum(II) precursors trans-[PtI(σ-C₆H₄R)(PPh₃)₂], followed by halogen metathesis with one equivalent of 4,7-phen. The reaction of trans-[Pt(σ-C₆H₄R)(4,7-phen)(PPh₃)₂]OTf with labile complexes of the type trans-[Pt(OTf)L₂(σ-C₆H₄R′)] (L=PEt₃, R′=H; L=PPh₃, R′=4-CO₂Si^tBuPh₂, 3-CO₂Si^tBuPh₂, 3-CONHMe) afforded the asymmetric dinuclear complexes of the type trans-[Pt(σ-C₆H₄R)L₂(μ-4,7-phen)Pt(σ-C₆H₄R′)L′₂](OTf) ₂ (L=PPh₃, R=4-CO₂Si^tBuPh₂, L′=PEt₃, R′=H; L=L′=PPh₃, R=4-CONHMe, R′=4-CO₂Si^tBuPh₂; R=4-CO₂Si^tBuPh₂, R′=3-CONHMe; R=3-CONHMe, R′=3-CO₂Si^tBuPh₂) in which the 4,7-phen acts as a bridging bidentate ligand. The novel dinuclear species undergo an unusual redistribution reaction that is essentially thermoneutral at 298 K. The exchange process involves facile cleavage of a Pt-N bond and the rapid exchange of trans-[PtL₂(σ-aryl)] units in the equilibrium mixture.     

Pseudoelementverbindungen. XI. [1] Untersuchungen zum Komplexbildungsverhalten von Cyanamidonitrat [NO2NCN]−

Pseudoelement Compounds. XI. [1] Investigations on the Coordination Behaviour of Cyanamidonitrate [NO₂NCN]^? With the ionic, potentially ambidentate ligand cyanamidonitrate complexes of the types [MX(PPh₃)₃], [MX(PPh₃)₂]₂ (M?Cu^I, Ag^I) and trans-[Pt(H)X(PPh₃)₂] (X^??[NO₂NCN]^?) are introduced. The new compounds are characterized by ¹H NMR, ³¹P NMR, and IR spectroscopy. The crystal structures of [Cu(NO₂NCN)(PPh₃)₂]₂ and [Ag(NO₂NCN)(PPh₃)₂]₂ are reported. In the complexes [MX(PPh₃)₃] and trans-[Pt(H)X(PPh₃)₂] cyanamidonitrate is unidentately coordinated through the nitrile group end-on. In the dimeric complexes [MX(PPh₃)₂]₂ the anion acts bidentately as a bridging ligand. Surprisingly, both coordinative bonds are formed through nitrogen atoms of the NCN group.     

Metal-thiophen derivatives. Organometallic compounds of palladium and platinum

Thienylmercury(II)chloride reacts with [Pd(PPh₃)₂Cl₂], [Pd(PPh₃)₄] and [Pt(PPh₃)₄] to afford new compounds containing a metal-2-thienyl linkage. The compound [Pd(PPh₃)₂(2-C₄H₃S)Cl] probably has trans stereochemistry.2-Bromothiophen undergoes oxidative addition with [Pd(PPh₃)₄] and [Pt(PPh₃)₄], probably via a radical mechanism. With [Pd(CO)(PPh₃)₃], a carbonyl inserted product is obtained. The bromo-metal(II) complexes have trans stereochemistry. The course of the reaction between 3-methyl-2-bromothiophen and Pd(PPh₃)₄ is more complex. Thus, there is evidence of some cis bromopalladium(II) compounds amongst the products, also there is good evidence to support the view that some isomerisation of 3-methyl-2-thienyl to 4-methyl-2-thienyl occurs during the reaction, thus giving greater molar quantities of [Pd(PPh₃)₂(4-CH₃-2-C₄H₂S)Br] than can be accounted for from any initial 4-methyl-2-bromothiophen impurity.The metallation of the thiophen ring, probably in the 4-position, with palladium(II) is described for 3-theylidene-4-methylaniline.     

Trifluoromethylselenato(0) and trifluoromethyltellurato(0) complexes of platinum(II)

The series of cis/trans-trifluoromethylselenato complexes [Pt(SeCF₃)_2 − xCl_x(PPh₃)₂] (x = 0, 1) was identified by NMR spectroscopic methods. While in acetonitrile solution spectra are dominated by the resonances of the cis derivatives, those of pure cis-[Pt(SeCF₃)₂(PPh₃)₂] indicate cis-trans-isomerisation in CH₂Cl₂ solution. In contrast, exchange reactions of cis-[PtCl₂(PPh₃)₂] and [NMe₄]TeCF₃ only gave evidence for cis isomers. Molecular structures of cis- and trans-[Pt(SeCF₃)₂(PPh₃)₂] and cis-[Pt(TeCF₃)₂(PPh₃)₂] are discussed in comparison with related compounds.     

Oxidative addition and insertion reactions of cyclic alkyne-platinum(0) complexes

The reactions of various alkyne-platinum(0) complexes with methyl iodide and with iodine have been studied. The 3-hexyne complex Pt(C₂H₅C₂C₂H₅)(PPh₃)₂ gives alkyne-free oxidative addition products PtI(CH₃) (PPh₃)₂ and PtI₂ (PPh₃)₂ exclusively. In contrast, the strained cyclic alkyne complexes Pt(C₆H₈)(PPh₃)₂, Pt(C₇H₁₀)(PPh₃)₂, Pt(C₆H₈) (dppe) and Pt(C₇H₁₀) (dppe)¹ react with methyl iodide to give mainly 2-methylcycloalkenyiplatinum(II) complexes, e.g. PtI(C₆H₈CH₃) (PPh₃)₂, formed by electrophilic attack on the metal-alkyne bond. Iodine reacts similarly with Pt(C₆H₈) (PPh₃)₂ and Pt(C₇H₁₀) (PPh₃)₂ to give 2-iodocycloalkenylplatinum(II) complexes but, in the case of the corresponding dppe complexes, PtI₂(dppe) is the main product. The insertion reaction of methyl iodide with Pt(C₆H₈)(PPh₃)₂ proceeds via an oxidative addition intermediate PtI(CH₃) (C₆H₈) (PPh₃)₂ which can be isolated. Trifluoromethyl iodide reacts with Pt(C₆H₈)(PPh₃)₂ to give a 2-iodocyclohexenyl complex Pt(CF₃) (C₆H₈I) (PPh₃)₂ and with Pt(C₇H₁₀) (PPh₃)₂ to give PtI(CF₃) (PPh₃)₂. ³¹P NMR data are given and discussed.     

The effect of tin(II) chloride on the liquid-liquid extraction of tetrachloroplatinate(II) ions by triphenylphosphine in dichloromethane

The effect of tin(II) chloride on the extraction of tetrachloroplatinate(II) in 1.0–1.5 M HCl into dichloromethane with triphenylphosphine (TPP) is described. Tin(II) chloride dramatically increases the rate and efficiency of platinum extraction. The percentage of platinum extracted depends in a complicated way on the time allowed for extraction, the Pt:Sn(II) ratio, the Pt:TPP ratio, and to a lesser extent to the hydrochloric acid concentration. Tin is initially extracted into the organic phase, probably as [Pt(SnCl₃)Cl(PPh₃)₂], but is subsequently back-extracted into the aqueous phase, as a result of the relatively slow disproportionation reaction: [Pt(SnCl₃)Cl(PPh₃)₂]_org + cl^? ? [Pt(PPh₃)₂Cl₂]_org + SnCl^?₃.     

The platinum—carbon bond strength in Pt(PPh3)2(Cl)(CPhCHPh)

The enthalpies of the reactions 1 and 2 have been determined as ΔH = Pt(PPh₃)₂(CPhCPh)_cryst. + HCl_g → Pt(PPh₃)₂(Cl)(CPhCHPh)_cryst. (1) Pt(PPh₃)₂(CPhCPh)_cryst. + 2HCl_g → cis-Pt(PPh₃)₂Cl_2cryst. + trans-CHPhCHPh_g (2) ?90.2 ± 6 and ΔH = ?139.0 ± 16 kJ mol^?1, respectively; dissociation energies of bonds involving platinum are expressed by the relationship: 41 kJ mol^?1 + D(Pt-tolane) = 2D(PtCPhCHPh) = {D₁(PtCl) + D₂(PtCl)} ?350 kJ mol^?1     

Reactions involving transition metals : XIX. Some reactions of perfluoronorbornadiene with low valent transition metal complexes

Perfluoronorbornadiene reacts with the compounds [M(PPh₃)₄] (M = Pt, Pd) and [IrCl(CO)(PMePh₂)₂] to give the adducts [(C₇F₈)M(PPh₃)₂] and [(C₇F₈)IrCl(CO)(PMePh₂)₂] in which one of the double bonds is coordinated to the metal atom. The platinum complex reacts further with [Pt(PPh₃)₄] to give [(C₇F₈){Pt(PPh₃)₂}₂] having both double bonds coordinated to a Pt atom. The carbonylmetal anions [M^?] react to form the mono-substitution products [(C₇F₇)M] (M = Mn(CO)₅, Re(CO)₅, Ir(CO)₂(PPh₃)₂, Rh(CO)₂(PPh₃)₂), but the use of an excess of [Fe(CO)₂(η-C₅H₆)]^? leads to substitution of one fluorine atom on each of the double bonds. The complex having M = Mn(CO)₅ reacts with [Pt(PPh₃)₄] to afford the derivative [(C₇F₇){Mn(CO)₄(PPh₃)}{Pt(PPh₃)₂}], and the compound where M = Ir(CO)₂(PPh₃)₂ undergoes an oxidative addition reaction with acetyl chloride. Oxidative coupling products have been isolated on UV irradiation of a mixture of perfluoronorbornadiene and [Fe(η⁴-CH₂CRCHCH₂)(CO)₃] (R = H, Me), and under similar conditions the reaction with Fe(CO)₅ affords [(C₇F₈)Fe(CO)₄] in very low yield.     

Organometallic formate complexes of platinum(II)

The compounds trans-[Pt(OCHO)R(PPh₃)₂] (R = C₆Cl₅; 2,3,4,6-C₆HCl₄; 2,3,4,5-C₆HCl₄; 2,5-C₆H₃Cl₂) have been prepared by treatment of [PtIR(PPh₃)₂] with AgClO₄ followed by reaction with NaOCHO in methanol. The cis isomers have been obtained by the direct reaction of HCO₂H with compounds containing PtHg bonds. For these and the analogous compounds containing C₆F₅ ligands, the dependence of J(³¹P¹⁹⁵Pt) on R has been studied, and the effects of cis-R shown to be in the opposite direction from those of trans-R ligands.     

Fulvene—platinum complexes: x-ray crystal structure of [Pt(η2-C5H4CPh2)(PPh3)2]

Bis(cycloocta-1,5-diene)platinum reacts with 2,3,4,5-tetraphenylfulvene to afford the complex [Pt(η²-CH₂C₅Ph₄)(cod)] (cod  C₈H₁₂) in which the metal atom is coordinated to the exo-cyclic double bond of the fulvene. Related compounds [Pt(η²-CH₂C₅Ph₄L₂] (L  PPh₃, PMePh₂, PMe₂Ph, AsPh₃ or CNBu^t have also been prepared and characterised. Reaction of the complexes [Pt(C₂H₄)₂(L)] (L  P(cyclo-C₆H₁₁)₃, PPh₃ or AsPh₃) with 2,3,4,5-tetraphenylfulvene yields the compounds [Pt(C₂H₄)(η²-CH₂C₅PH₄)(L)]. NMR data for the new species are reported and discussed. 6,6-Diphenylfulvene reacts with [Pt(cod)₂] and PPh₃ ($\text{1}\text{2}$ mol ratio) to give the complex [Pt(η²-C₅H₄CPh₂)-(PPh₃)₂] in which the metal atom is bonded to carbon atoms C(2) and C(3) of the fulvene ring. This was established by an X-ray diffraction study. Crystals are monoclinic, space group P2₁/n, with Z  4 in a unit cell of dimensions a  13.761(4), b  21.653(13), c  17.395(6) Å, β,  104.46(2)°. The structure has been solved and refined to R  0.064 (R′  0.064) for 3139 independent diffracted intensifies measured at room temperature. The platinum atom is in a trigonal environment formed by the two ligated phosphorus atoms and the CC bond of the fulvene which is elongated to 1.52(3) Å. The c₅ fulvene ring is planar, and makes an angle of 108° with the coordination plane around the platinum. In this plane the metal atom is slightly asymmetrically bonded with PtC 2.15(2) and 2.24(2) Å, and PtP 2.280(6) and 2.301(6) Å.     

REACTIONS OF CARBONYLSULPHIDE WITH [Rh(PPh3)3CI] AND [Pt(PPh3)3]

Abstract

Activation of small inorganic molecules (H₂, N₂, O₂, CO, NO, CO₂, SO₂, CS₂) by the complexes of transition metal ions like Rh(I), Ir(I), Pt(O) and Ru(II) have gained considerable interest during the last decade.^1–8 Because of the similarity of CO₂ and CS₂ molecules with COS, one would expect COS to form complexes with the transition metal ions analogous to those of CO₂ and CS₂. In addition, COS being susceptible to decomposition into CO and S, could also form carbonyl complexes. Until now, the only reaction of COS that has been successfully carried out is with [Pt(PPh₃)₃] which resulted in the formation of [Pt(COS)(PPh₃)₂] and [Pt₂S(CO) (PPh₃)₃]. ^8,9 It will, therefore, be interesting to study further the reactions of COS with the complexes of transition metal ions. The results of a preliminary study of such reactions with [Rh(PPh₃)₃Cl] and [Pt(PPh₃)₃] are reported in this communication.