Cycloaddition Reactions of the Phosphinidene-Bridged Complex [MoCp(μ-κ:κ,η-PCH)(CO)(η-HMes*)] with Diazoalkanes and Other Heterocumulenes.

The title phosphinidene complex reacted at room temperature with CS and SCNPh to give the phosphanyl derivatives [MoCp{μ-κ:κ,η-P(CS)CH}(CO)(η-HMes*)] and [MoCp{μ-κ:κ,η-P(C(NPh)S)CH}(CO)(η-HMes*)], respectively (Mes* = 2,4,6-CHBu), which result from a [2 + 2] cycloaddition of a C═S bond in the organic reagent to the Mo═P bond of the phosphinidene complex, with further insertion of S into the remaining Mo-P bond, in the CS reaction. The title complex also reacted with diazoalkanes NCRR' at room temperature to give the corresponding phosphaalkene derivatives [MoCp{μ-η:κ,η-P(CRR')CH}(CO)(η-HMes*)] (CRR' = CH, CPh, CH(SiMe)). These products follow from a formal [2 + 1] cycloaddition of the carbene CRR' fragment to the Mo═P bond of the parent compound but were shown to proceed through a [3 + 2] cycloaddition of the diazoalkane molecule, followed by N elimination.

Gold(I) and related heterometallic derivatives of dimolybdenum complexes with asymmetric phosphinidene bridges.

The phosphinidene-bridged complexes [Mo2Cp2(μ-κ(1):κ(1),η(6)-PR*)(CO)2] (1), [Mo2Cp2(μ-κ(1):κ(1),η(4)-PR*)(CO)3] (2), [Mo2Cp(μ-κ(1):κ(1),η(5)-PC5H4)(η(6)-HR*)(CO)2] (3), and [Mo2Cp2(μ-κ(1):κ(1)-PH)(η(6)-HR*)(CO)2] (4) were examined as precursors of heterometallic gold(I) and related derivatives (Cp = η(5)-C5H5, R* = 2,4,6-C6H2(t)Bu3). These complexes reacted with [AuCl(THT)] to give the corresponding derivatives [AuMo2ClCp2(μ-κ(1):κ(1):κ(1),η(6)-PR*)(CO)2], [AuMo2ClCp2(μ-κ(1):κ(1):κ(1),η(4)-PR*)(CO)3] (Au-Mo = 2.8493(6) Å), [AuMo2ClCp(μ-κ(1):κ(1):κ(1),η(5)-PC5H4)(CO)2(η(6)-HR*)], and [AuMo2ClCp2(μ3-PH)(CO)2(η(6)-HR*)] formally resulting from the addition of an acceptor AuCl moiety to the short Mo-P bond of the parent substrates almost perpendicular to the corresponding Mo2P plane.

Dimolybdenum cyclopentadienyl complexes with bridging chalcogenophosphinidene ligands.

The reactions of the phosphinidene-bridged complex [Mo(2)Cp(2)(μ-PH)(η(6)-HMes*)(CO)(2)] (1), the arylphosphinidene complexes [Mo(2)Cp(2)(μ-κ(1):κ(1),η(6)-PMes*)(CO)(2)] (2), [Mo(2)Cp(2)(μ-κ(1):κ(1),η(4)-PMes*)(CO)(3)] (3), [Mo(2)Cp(2)(μ-κ(1):κ(1),η(4)-PMes*)(CO)(2)(CN(t)Bu)] (4), and the cyclopentadienylidene-phosphinidene complex [Mo(2)Cp(μ-κ(1):κ(1),η(5)-PC(5)H(4))(η(6)-HMes*)(CO)(2)] (5) toward different sources of chalcogen atoms were investigated (Mes* = 2,4,6-C(6)H(2)(t)Bu(3); Cp = η(5)-C(5)H(5)). The bare elements were appropriate sources in all cases except for oxygen, in which case dimethyldioxirane gave the best results. Complex 1 reacted with the mentioned chalcogen sources at low temperature, to give the corresponding chalcogenophosphinidene derivatives [Mo(2)Cp(2){μ-κ(2)(P,Z):κ(1)(P)-ZPH}(η(6)-HMes*)(CO)(2)] (Z = O, S, Se, Te; P-Se = 2.

A thiophosphinidene complex as a vehicle in phosphinidene transmetalation: easy formation and cleavage of a P-S bond.

A method for the generation of transition metal-phosphorus multiple bonds has been developed using the reactions of a novel thiophosphinidene-bridged dimolybdenum complex with different metal carbonyls. The overall process could be considered as a transmetalation of the phosphinidene ligand involving the activation of P-S and P-Mo bonds.

Aurophilic self-assembly of a Mo4Au2 phosphinidene complex with an unprecedented H-shaped planar metal core.

The isomers [Mo2Cp2(mu-kappa(1):kappa(1),eta(6)-PR*)(CO)2] (1) and [Mo2Cp(mu-kappa(1):kappa(1),eta(5)-PC5H4)(CO)2(eta(6)-HR*)] (2) (Cp = eta(5)-C5H5; R* = 2,4,6-C6H2(t)Bu3) react with [AuCl(THT)] and with the cation [Au(THT)2](+) (THT = tetrahydrothiophene) to give phosphinidene-bridged Mo2Au complexes resulting from the addition of an AuCl or Au(THT)(+) electrophile to their multiple P-Mo bonds. Removal of the Cl(-) or THT ligand from these derivatives causes a dimerization of the trinuclear structures to give the cationic derivative [{AuMo2Cp(mu3-kappa(1):kappa(1):kappa(1),eta(5)-PC5H4)(CO)2(eta(6)-HR*)}2](2+), which displays a novel H-shaped metal core held by strong Mo-Au dative bonds [2.768(1) A] and an aurophilic interaction [Au-Au = 3.

Carbene- and carbyne-like behavior of the Mo-P multiple bond in a dimolybdenum complex inducing trigonal-pyramidal coordination of a phosphinidene ligand.

The phosphinidene complex [Mo2Cp(micro-kappa1:kappa1,eta5-PC5H4)(CO)2(eta6-R*H)] (2; Cp = eta5-C5H5; R* = 2,4,6-C6H2tBu3) has substantially different Mo-P bonds and displays a high reactivity located at the short Mo-P bond. Sideways cycloaddition or addition processes are observed toward RCCR, HCl, and [Fe2(CO)9], to give respectively metallacyclobutene and arylphosphide-bridged and heterometallic phosphinidene-bridged derivatives, a behavior reminiscent of the nucleophilic mononuclear phosphinidene complexes (carbene-like behavior), which is in good agreement with the ground-state electronic structure of 2 derived from density functional theory calculations. However, the reaction of 2 with [Co2(CO)8] implies the addition of two cobalt fragments to its short Mo-P bond and thus reveals a carbyne-like behavior of compound 2.