Utilizing Steric Bulk to Stabilize Molybdenum Aminogermylyne and Aminogermylene Complexes

Abstract

Two extremely bulky bis(aryl)amines, HN(Ar*)(Ph) (HLPh) and HN(Ar*)(Mes) (HLMes) (Ar* = C6H2{C(H)Ph2}2Me-2,6,4; Mes = mesityl), have been prepared by palladium-catalyzed cross-coupling reactions and structurally characterized. These have been utilized in the preparation of the amido-germanium(II) chlorides, [LPhGeCl] and [LMesGeCl]. Reactions of these, and the known complex, [L′GeCl] (L′ = −N(Ar*)(SiMe3)), with Na[CpMo(CO)3] have afforded the first examples of structurally characterized two-coordinate molybdenum substituted germylenes, [Cp(CO)3MoGeN(Ar*)(R)] (R = SiMe3 or Ph). The former readily eliminates a molecule of CO when heated or irradiated with UV light to give an unprecedented amino-germylyne complex, [Cp(CO)2MoGeN(Ar*)(SiMe3)]. The spectroscopic and structural data for this complex, in combination with the results of computational studies, show that this compound is best viewed as having a bent Mo–Ge “triple” bond, with little multiple bond character to its Ge–N interaction. Computational studies have also indicated that the Mo–Ge–N bending in the complex is due to the extreme steric bulk of its amido substituent.

Two-coordinate group 14 element(ii) hydrides as reagents for the facile, and sometimes reversible, hydrogermylation/hydrostannylation of unactivated alkenes and alkynes

“…Recently, we have utilised extremely bulky amide ligands, developed in our group, 15 to kinetically stabilise amido/hydrido-digermenes, e.g. [L † (H)Ge Ge(H)L † ] 1 (L † = –N(Ar † ) (SiPr i 3 ); Ar † = C 6 H 2 {C(H)Ph 2 } 2 Pr i -2,6,4), 16 and isomeric dimeric hydrido-bridged stannylenes, e.g.…”

Synthese und Hydrierung schwerer Homologe eines Rhodium‐Carbins: [(Me3P)2(Ph3P)Rh≡E‐Ar*] (E=Sn, Pb)

“…In den Koordinationsverbindungen 3 und 7 sind zwei Tr iphenylphosphane und zwei Hydridliganden quadratisch planar cis-koordiniert, wobei der Fall des Zinnderivates leicht kürzere Rh-P-und Rh-H-Abstände aufweist. Die Rh-P-Abstände [2.2741(7)-2.2897(9) ]l iegen im Bereich von quadratisch planar koordinierten (Ph 3 P) 2 Rh(I)-Fragmenten, welche von closo-Boraten über BH-Wechselwirkungen oder von Cp 2 WH 2 durch Hydridkoordination stabilisiert sind [2.2192(6)-2.2391 (6) ]. [13] Die Position der Hydride in 3 und 7 wurden den Differenz-Fourierkarten entnommen und mit festgelegten Abständen verfeinert.…”

Extremely bulky amide ligands in main group chemistry

“…78 Remarkably, increasing the steric bulk of the amide ligand does not lead to the formation of the monomeric species, but instead yields i Pr 3 Si(Ar † )NGeGeN(Ar † )Si i Pr 3 (123), which unlike 114 features a Ge-Ge multiple bond. 15), which unlike the m-terphenyl analogue 94 77,96 The germaniumcentred free radical formed from the positive muon irradiation of 113 has been investigated by muon spin spectroscopy. The Ge-Ge distance for 123 is 2.3568(3) Å -more than 0.35 Å shorter than that in 114.…”