Photochemical Reaction of Mo(CO)₆ with Et₂GeH₂: NMR and DFT Studies of Reaction Products; Crystal Structure of a Novel Complex [{Mo(μ-η²-H−GeEt₂)(CO)₄}₂]

Abstract

The photochemical reaction of Mo(CO) 6 with the diethylgermane Et 2 GeH 2 leads to the formation of several new complexes, which were detected by IR and 1 H and 13 C NMR spectroscopy. From the mixture of compounds, a binuclear complex, [{Mo(μ-η 2 -H-GeEt 2 )(CO) 4 } 2 ], was isolated in crystalline form, and its molecular structure was established by single-crystal X-ray diffraction studies. The agostic hydride ligand of the Mo( μ-η 2 -H-GeEt 2 ) group was located in the structure at a chemically reasonable position between the Mo and Ge atoms of the Mo-Ge bond of the bridging germyl ligand, and its presence was confirmed by 1 H NMR spectroscopy due to a proton resonance at δ = -7.86. Two dihydride complexes were identified by 1 H and 13 C NMR spectroscopy, due to their differing thermal behavior. A DFT study of the structural properties of possible reaction products was performed.

Strength of Si–H ⋯ B charge-inverted hydrogen bonds in 1-silacyclopent-2-enes and 1-silacyclohex-2-enes

“…All calculations have been performed utilizing the PBE0 [37][38][39] exchange-correlation functional of density functional theory and the 6-311G(d,p) basis set [40,41]. It was shown that PBE0 gives reasonable molecular structures [12,42] as well as electronic densities [43,44]. On the other hand, the 6-311G(d,p) basis set is of valence triple zeta quality and, additionally, includes polarization functions for all atoms.…”

Intercepting low oxidation state main group hydrides with a nucleophilic N-heterocyclic olefin

“…Overall, the structure of the GeH 2 adduct 5 is similar to its tin congener 4 (Fig. S4, ESIw), with a canted transoid arrangement of the C(7)-C(6)-Ge-W unit [torsion angle = 146.45 (14) 17 and IPrÁGeH 2 ÁBH 3 [2.011(2) A ˚]. 3 The proximal C(6)-C(7) bond length was 1.463(3) A ˚and lies within the range expected for a C-C single bond; as in 4, the endocyclic C(7) center in the Ge adduct was planar [angle sum = 360.0(3)1].…”

Carbonyl Complexes of Molybdenum and their Catalytic Activity

“…Recently, the ability of photochemically generated coordinatively unsaturated carbonyl complexes of molybdenum(0) to activate the Ge-H -bond of germanes has been discovered and taken advantage of in the hydrogermylation of norbornadiene [80,81]. In photochemical reaction of Mo(CO) 6 , [Mo(CO) 4 (nbd)], or [Mo(CO) 4 (cod)] with Et 3 GeH, the 2 -coordination of the Ge-H bond to the molybdenum atom was detected by 1 H NMR spectra, due to characteristic high-field resonance in the region from -6 to -8 ppm.…”

“…Carbonyl complexes of molybdenum are of great utility owing to their applications as precursors for the generation of true catalysts for such reactions as metathesis , metathesis polymerization and oligomerization [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56], radical reactions [57][58][59][60][61][62][63][64][65], hydrogenation [66][67][68][69][70][71][72][73][74], hydrosilylation [75][76][77][78][79], hydrogermylation [80,81], hydrostannation [82][83][84][85][86][87]…”

“…In that way the coordinated alkene or alkyne can be transformed to a carbene ligand [8-25, 45, 46, 50]. The activation of a -bond (H H, H C, H Si, H Ge, H Sn) of a substrate such as dihydrogen [66][67][68][69], silane [75][76][77][78], germane [80][81], stannane [82], or aromatic hydrocarbon molecules is a key step in the catalytic transformation of such molecules. Recent investigations of molybdenum carbonyl complexes have revealed novel types of their reactivity toward unsaturated organic compounds, e.g.…”