126925-92-6Relevant articles and documents
S-H Bond activation in H2S and thiols by [RhMn(CO)4(Ph2PCH2PPh2) 2]. Compounds containing terminal or bridging sulfhydryl and thiolato groups
Wang, Li-Sheng,McDonald, Robert,Cowie, Martin
, p. 3735 - 3744 (2008/10/08)
The complex [RhMn(CO)4(dppm)2] (dppm = Ph2PCH2PPh2) reacts with H2S and thiols to yield the products [RhMn(SR)(CO)3(μ-H)(dppm)2] (R = H, Et, Ph), containing terminal sulfhydryl or thiolato groups bound to Rh and a bridging hydride ligand. The sulfhydryl species loses H2 over the period of several days and scavenges CO to yield [RhMn(CO)4(μ-S)(dppm)2]. This sulfide-bridged product can be protonated or alkylated to give the cationic species [RhMn(CO)4(μ-SR)(dppm)2]+ (R = H, CH3, CH2SiMe3), containing bridging sulfhydryl or thiolato groups. The bridging sulfhydryl group in [RhMn(CO)4(μ-SH)(dppm)2]+ undergoes a Michael-type addition to alkynes to yield [RhMn(CO)4(μ-SC(R)=C(H)R′)(dppm)2]+ (R = H, R′ = C(O)Me; R = R′ = CO2Me) in which the unsaturated thiolato group bridges the metals. With hexafluoro-2-butyne, an analogous reaction occurs to yield the related species [RhMn(SC(CF3)=C(H)CF3)(CO)4(dppm) 2]+, but in this case the thiolato group is terminally bound to Rh. The structure of [RhMn(CO)4(μ-S)(dppm)2] has been determined by X-ray crystallography. This compound crystallizes in the monoclinic space group P21/n, with a = 12.419(4) A?, b = 25.735(2) A?, c = 16.464(2) A?, β = 97.70(2)°, V = 5215(3) A?, and Z = 4, and has refined to R = 0.055 and Rw = 0.071 on the basis of 5865 unique observations and 598 parameters varied. This compound shows a semibridging carbonyl group which is primarily bound to Mn (Mn-C(2) = 1.959(5) A?, Rh-C(2) = 2.214(5) A?), in line with the small Rh-C coupling of 8 Hz observed in the 13C NMR for this carbonyl.
A convenient general route to a series of diphosphine-bridged heterobinuclear complexes that contain rhodium and structures of the mixed-valent complexes [RhM(CO)4(Ph2PCH2PPh2)2] (M = Mn, Re)
Antonelli, David M.,Cowie, Martin
, p. 1818 - 1826 (2008/10/08)
A convenient route to a series of dppm-bridged complexes has been developed in which the chloride anion in [RhCl(dppm)2] is displaced by a metal carbonylate anion. This metathesis reaction is accompanied by unwinding of one or both of the chelating dppm groups to adopt a bridging arrangement and by loss of one carbonyl group. In the compounds [RhCo(CO)3(dppm)2], [RhMH(CO)3(dppm)2] (M = Fe, Ru, Os), [RhM(CO)4(dppm)2] (M = Mn, Re), and [RhMH(CO)4(dppm)2] (M = Cr, W), both diphosphines adopt a bridging arrangement, whereas in [RhFeCp(CO)(dppm)2] and [RhMoCp(CO)2(dppm)2] only one dppm group bridges the metals while one remains chelating on rhodium. The structures of [RhM(CO)4(dppm)2] (M = Mn (5), Re (6)) have been determined by X-ray methods. The coordination geometries at Mn and Re are not octahedral, but instead (ignoring the Rh atoms), the [M(CO)3L2] (L = one end of dppm unit) moieties have trigonal-bipyramidal geometries, suggesting that a M(-I) formulation is appropriate. This [M(CO)3L2]- fragment then functions as a pseudohalide, forming a dative M→Rh bond and giving the Rh center a square-planar arrangement consistent with a Rh(+I) formulation. The resulting M-Rh bond lengths are 2.8428 (8) ? (M = Mn) and 2.7919 (6) ? (M = Re). Compound 5 crystallizes in the triclinic space group P1 with a = 10.897 (2) ?, b = 11.046 (2) ?, c = 11.700 (2) ?, α = 68.14 (1)°, β = 67.48 (1)°, γ = 87.69 (1)°, V = 1198.7 (4) ?3, and Z = 1 and was refined to R = 0.054 and Rw = 0.082. Compound 6 crystallizes together with one THF molecule in the monoclinic space group P21/c with a = 12.963 (4) ?, b = 19.883 (3) ?, c = 11.277 (2) ?, β = 99.12 (2)°, V = 2870 (2) ?3, and Z = 2 and was refined to R = 0.053 and Rw = 0.088. Both compounds occupy a crystallographic inversion center so the metal carbonyl fragments are disordered, although this disorder, in reality, is readily handled crystallographically, with only two carbonyl carbons having two sets of half-occupancy positions and each metal position being composed of one half-occupancy rhodium atom and one half-occupancy manganese or rhenium atom.
