Metal carbonyls reaction with phosphites

Basolo and co-workers recently studied CO substitution in [V(CO)6], which is the only stable homoleptic metal carbonyl radical. With phosphine and phosphite nucleophiles (L) reaction (1) follows a strictly second-order... 

The relative amounts of the products depend on irradiation time, and the formation of the bis (triphenyl phosphite) chromium complex may be almost completely avoided by following the reaction with thin layer chromatography. The diastereoisomers are air stable and reasonably soluble in most organic solvents. Their infrared spectra exhibit a metal carbonyl band at 1925 cm 1 (i>co ester at 1729 cm"1) and a metal thiocarbonyl band at 1925 cm"1 (CH2C12 solution). The NMR spectra. I 5ch3 at 1.87 ppm 5co3CH3 at 3.77 ppm II 6ch3 at 1.77... 

Under more severe conditions, mononuclear products can be obtained from the reaction of Group V ligands with second- and third-row metal carbonyl clusters. Ru3(CO)i2 reacts with L at 140°C to produce Ru(C0)sL2 [L = PPhs, PBus, P(OPh)3] (326, 327). Similar reactions occur with Os3(CO)i2 (46), Ru3(CO)g(PPh3)3, and Os3(CO)9(PPh3)3 (326). Ir4(CO)i2 produces Ir2(C0)4Lg with trialkyl and triaryl phosphites (386). It is reported that Rh4(CO)i2 and Rhe(CO)i6 react with Ph3P to form Rh4(CO)io(PPh3)2, which subsequently decomposes to Rh2(CO)4(PPh3)4 (88). 

Thermal Substitution.—Carbonyl substitutions in Group VI metal carbonyls occur predominantly by dissociative pathways, associative pathways also contributing when the more nucleophilic incoming ligands are considered. The kinetics of the reaction of [W(CO)3(CS)(phen)] with ligands L (phosphines or phosphites) to give [W(CO)3(CS)L(phen)] show first- and second-order terms... 

Mixed Ligand Carbonyls.—General. Solvent and structural effects on reactivities of metal carbonyl halides towards carbon monoxide replacement have been probed for manganese, iron, and ruthenium compounds. The compounds were MnX(CO>5, where X == Br or I, RuX(CO)2(/i -C6H6), where X = Cl or Br, and FeX(CO)2(/i -C3H5), where X = Br or I. The displacing nucleophiles were triphenylphosphine or triphenyl phosphite the solvents were n-octane, xylene, di-n-butyl ether, or nitrobenzene. Kinetic parameters for some of these reactions, with some earlier values for related systems for comparison, are listed in Table 1. The main conclusion... 

In case of heterobimetallic Ir/Rh analogs, reaction of [RhIr(CH3)(CO)3(dppm)2]OTf 127 with several phosphines and phosphites yields the carbonyl-substitution product [RhIr(CH3)(PR3)(CO)2(dppm)2]OTf 128, in which the added phosphine and the Me ligands are coordinated to Ir. At —80°C, an intermediate in this reaction, [RhIr(CH3)(PR3)(CO)3(dppm)2]OTf 129, is observed with PR3 bound to Rh. Similar reactions with the dicarbonyl compound [RhIr(CH3)(CO)2(dppm)2]OTf 130 suggest that attack occurs directly at Ir in this case. The structure of 129 is slightly different in solution, having the carbonyls both terminally bound one to each metal in solution, but having one bridging in the solid. ... 

Iridium(I) dithiocarbamate complexes have been the subject of a paper by Duckett and co-workers (1451). Reaction of NaS2CNEt2 with [lr(cod)(p-Cl)]2 gives [lr(S2CNEt2)(cod)] from which a range of carbonyl, phosphine, and phosphite complexes are readily prepared via displacement of the diolefin, some of which exhibit luminescence in fluid solution at room temperature. Benzene solutions of [lr(S2CNEt2) P(OPh)3 2] are unstable and result in slow formation of the ortho-metalated iridium(lll) hydride, [IrH(S2CNEt2) P(0Ph)3 P(0Ph)20CeH4 ] (Eq. 140), characterized by a hydride resonance at 8 -16.02. 

Alternatively, acyliron complexes can be obtained in a two-step sequence either from dicarbonyl(cyclopentadienyl)ferrates or from dicarbonyl(cyclopentadienyl)iron halides via alkyl-Fp complexes. The first method makes use of the nucleophilicity of [CpFe(CO)2] anions. Their reaction with alkyl halides provides alkyl-Fp complexes that, upon treatment with phosphanes or phosphites, undergo a migratory insertion of a carbonyl ligand into the metal-alkyl bond leading to an acyliron complex (Scheme 4-38). " ... 

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