Synthesis, characterization and reactivity of the silylated diphosphites [(R1O)2PO]2SIR2R3 (R1 Me, Et; R2, R3 Me, Ph, H, CHCH2). Crystal structure of [MnBr(CO)3{P(OMe)2O}2SiMe2]

Versatile Phosphite Ligands Based on Silsesquioxane Backbones

“…Mo À P bond lengths of 2.4771(10) ä (Mo À P1) and 2.4509(10) ä (Mo À P2) are in good agreement with the structures reported by Gray et al [29,32] and by Kee and co-workers [30] on Mo complexes containing silyldiphosphites. The phosphorus-oxygen bond lengths of 1.574(3) ä for P1 À O3 and 1.575(3) ä for P2 À O6 are slightly shorter than in the silylphosphite systems (generally above 1.60 ä).…”

“…These values agree reasonably well with other cis-Mo(CO) 4 (phosphite) 2 complexes. [29,30] In the 31 P NMR spectrum of the crude reaction mixture a singlet was observed at d 149.6 ppm together with a minor peak at d 131.3 ppm indicating the small excess of free ligand. To get a confirmation of the actual coordination of the ligand to the molybdenum atom, a crystallographic study was undertaken, since single crystals could be grown by slow diffusion of acetonitrile into a dichloromethane solution of Mo(CO) 4 (3).…”

Electronic Properties of 4,4‘,5,5‘-Tetramethyl-2,2‘-biphosphinine (tmbp) in the Redox Series fac-[Mn(Br)(CO)3(tmbp)], [Mn(CO)3(tmbp)]2, and [Mn(CO)3(tmbp)]-: Crystallographic, Spectroelectrochemical, and DFT Computational Study

“…Thus, Mn-C eq bond distances in 2 (1.848(4) and 1.875(4) Å) are apparently longer than those found in related complexes fac-[Mn(I)(CO) 3 (bpy)] (1.77(2) and 1.80(2) Å) 10 and fac-[Mn(Br)(CO) 3 {((MeO) 2 PO) 2 SiMe 2 }] (1.810(4) and 1.832( 14) Å). 32 The weaker π-back-bonding toward the two equatorial CO ligands in 2 is also evidenced by a shortening of the CO bonds: 1.083(5) and 1.116(5) Å in 2 compared to 1.14( 2) and 1.19( 2) Å in fac-[Mn(I)(CO) 3 (bpy)], and 1.122(18) and 1.148(19) Å in the above diphosphite complex.…”

Silicon based phosphines with P_Si_P, P_C_Si_C_P and P_O_Si_O_P linkages and their coordination chemistry and catalytic applications

“…The facial geometry of the manganese complexes is supported by the three n (CO) bands in the IR spectrum. Further, the structure of one of the complexes ( 64) is confirmed by a singlecrystal X-ray diffraction study [14,15]. Similarly the silylbis(phosphinite), Me 2 Si[OP(tol) 2 ] 2 reacts smoothly with MnBr(CO) 5 at r.t. in toluene to afford the tricarbonyl derivative 68 in good yield [29].…”

“…31 P-NMR investigations have suggested that the nature of the silicon substituents has only a small effect on through-bond electronic induction or hybridization at the phosphorus atoms of the free bis(phosphites). Complexation of these bis(phosphites) to transition metals stabilizes the ligand towards hydrolysis compared with the uncoordinated ligands, which are otherwise highly air and moisture sensitive [15]. Experimental details are given in Table 4.…”