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Os(CHF2)Cl(CO)2(PPh3)2 reacts with BCl3 to give the title metallacycle, (4), which is the product of addition of a CHCl-ligand to the benzene ring of ligated triphenylphosphine and further reaction with BCl3 generates the title metallabicyclic complex, (5).

Reaction of the 2-chloro-derivatives of 5-methyl-1,3-thiazole, benzthiazole, and benzoxazole with IrCl(CO)(PMe2Ph)2 affords IrIII complexes which on protonation yield cationic carbene complexes [IrCl2(CO)(PMe2Ph)2(L)]+(L = [graphic omitted], [graphic omitted], [graphic omitted]). Treatment of IrCl(CO)(PMe2Ph)2 with the N-methyl salt of 2-chloro-5-methyl-1,3-thiazole, [Cl[graphic omitted]][BF4], affords the carbene complex [IrCl2(CO)(PMe2Ph)2{[graphic omitted]}][BF4]. Similar oxidative-addition of [Cl[graphic omitted]][BF4] to Pt(PEt3)2(stilbene), Pt(PMePh2)4, PdL4(L = PPh3, PMePh2) or Ni(PPh3)4 gives cationic carbene complexes of PtII, PdII, and NiII. The complex [PtCl{[graphic omitted]}(PEt3)2][BF4] was obtained by treating PtCl([graphic omitted])(PEt3)2 with fluoroboric acid. Some chemical and spectroscopic properties of the new complexes are discussed.

[IrH(CS)(PPh3)3] reacts with 2 equiv. of H2 to give [IrH2(SMe)(PPh3)3], and further reaction with HCl releases MeSH and forms [IrH2Cl(PPh3)3]; a thioformyl complex is a likely intermediate in this process and a stable example of such a compound is [Ir(CHS)Cl2(CO)(PPh3)2] from [IrCl2(CS)(CO)(PPh3)2]+ and NaBH4.

[OsHCl(CS)(PPh3)3] reacts with CO giving a blue thioformyl complex [Os(CHS)Cl(CO)2(PPh3)2]; this is readily methylated on sulphur forming a secondary thiocarbene complex which upon hydrolysis yields a formyl complex, [Os(CHO)Cl(CO)2(PPh3)2].

New carbene complexes of IrI, RhI, MnI, Cr0, and Fe0 have been prepared by reactions of the appropriate carbonylmetal anions with N-methyl- and N-ethyl-2-chloro-4-methylthiazolium tetrafluoroborate and N-methyl-2-chloropyridinium tetrafluoroborate. The anions [Ir(CO)3PPh3]–, [Rh(CO)2(PPh3)2]–, and [Mn(CO)5]– afford cationic carbene complexes, whereas [Cr(CO)5]2– and [Fe(CO)4]2– yield neutral carbene complexes. Treatment of [Mn(CO)5{[graphic omitted]}][BF4] with iodide ion gives a neutral complex [cis-Mnl(CO)4{[graphic omitted]}].The cation [Ir(CO){[graphic omitted]}(PPh3)2]+ reacts with hydrogen to give [IrH2(CO){[graphic omitted]}(PPh3)2]+. The cation also reacts oxidatively to give IrIII complexes with HCl, Cl2, and I2. Lithium chloride or bromide reacts to give [IrH(X)(CO){[graphic omitted]}(PPh3)2][BF4](X = Cl or Br), whereas [Ir(CO){[graphic omitted]H}(PPh3)2][BF4] affords the neutral IrIII species [IrCl3{[graphic omitted]H}(PPh3)2]. Methyl iodide reacts with [Ir(CO){[graphic omitted]}(PPh3)2][BF4] to give [Irl2Me(CO){[graphic omitted]}(PPh3)].Some spectroscopic properties of the new complexes are reported.

Deprotonation of [OsCl(PH2Ph)(CO)2(PPh3)2]+ gives the terminal phosphido-complex, [Os(PHPh)Cl(CO)2(PPh3)2], which has pyramidal geometry at P and associated nucleophilic properties, e.g., protonation and methylation at P, but [Os(PHPh)Cl(CO)2(PPh3)2] also reacts with methoxide to form the zerovalent compound [Os{PH(Ome)Ph}(CO)2(PPh3)2] suggesting the intermediacy of the planar phosphido-complex [Os(PHPh)(CO)2(PPh3)2]+.

Reaction of IrCl (CO)(PPh3)2 with silver perchlorate in various solvents gives [Ir(CO)(solvent)(PPh3)2]ClO4. Crystalline salts have been isolated where solvent = acetonitrile, benzonitrile, and dimethyl sulphoxide. [Ir(CO)(CH3CN)(PPh3)2]+ redily undergoes substitution reactions with carbon monoxide, phosphines, and isocyanides and, the following cations hsve been characterised: [Ir(CO)3(PPh3)2]+, [Ir(CO)(PPh3)3]+, [Ir(CO)(PPh2Me3)]+, [Ir(CO)(PPh2Et)3]+, [Ir(PPh2Me)4]+, [Ir(CO)(Ph2PCHCHPPh2)2]+, [Ir(CO)(p-Tolylisocyanide)(PPh3)2]+ and [Ir(p-tolylisocyanide)3(PPh3)2]+

[IrCl{(NO)(PPh3)2]+, the nitrosyl analogue of IrCl(CO)(PPh3)2 has been prepared by chlorination of [Ir(NO)2-(PPh3)2]+ or by reaction of IrHCl(NO)(PPh3)2 with non-co-ordinating acids. Five-co-ordinate addition products are formed with the neutral ligands CO, PPh3, Ph2PCH2CH2PPh2, Ph2PCHCHPPh2, and P(OPh)3 while the co-ordinating anions (X–), NO2–, Cl– and HS–, form IrX2(NO)(PPh3)2. Hydrolysis of [IrCl(NO)(PPh3)2]+ produces [Ir(OH)(NO)(PPh3)2]+ and this same hydroxo-cation, together with triphenylphosphine oxide, results from the reaction of [IrH(NQ)(PPh3)2]+ with dioxygen. [Ir(OH)(NO)(PPh3)2]+ forms [Ir(OR)(NO)(PPh3)2]+ in alcohols, (R = Et or Prn) and these cations are returned to [IrH(NO)(PPh3)3]+ by the action of hydrogen in the presence of triphenylphosphine. Another member of this four-co-ordinate, d8, nitrosyl cation series, [Ir(CH9)(NO)(PPh3)2]+, was prepared from Ir(CH4)I(NO)(PPh3)2 by reaction with silver ions. The tendency towards five-co-ordination within the series is compared.

OsH(CO)(NO)(PPh3)2 eliminates H2 when treated with acids HY (Y = ClO4, BF4, or PF6) in the presence of CO, forming [Os(NO)(CO)2(PPh3)2]Y; one carbonyl group is easily displaced from this cation by other ligands and an X-ray structure determination of [Os(NO)(CO)2(PPh3)2]ClO4, CH2Cl2 reveals trigonal bipyramidal geometry with a linear nitrosyl group.

The dioxygen complex, Ru(O2)(CO)(CNR)(PPh3)2(R =p-tolyl), reacts with alcohols, R′CH2OH (R′= Me, Et, or Ph) forming Ru(O2CR′)(CHNR)(CO)(PPh3)2; when the bidentate carboxylate group is replaced by iodide the ruthenium hydride RuHI(CO)(CNR)(PPh3)2 results which reacts with acetate with returns of hydride to the isocyanide ligand forming Ru(O2CMe)(CHNR)(CO)(PPh3)2.