Syntheses and structural analysis of the sterically encumbered germanes (o-ButC6H4)3GeX (X = Br, H, Cl, OH), (o-ButC6H4)2GeBr2, and Mes2GeH2: distortions arising from the presence of an ortho-tert-butyl substituent

Four new ortho-tert-butylphenyl substituted germanes (o-ButC6H4)3GeX (X = Br (1), H (2), Cl (3), or OH (4)) have been prepared and structurally characterized. The structures of 1–4 have been obtained and the ortho-tert-butyl substituents were found to be oriented in the same direction as the Ge–X bond in each molecule. The presence of these bulky substituents results in distortions in 1–4 from the ideal tetrahedral geometry, which was assessed by an examination of the Cipso–Ge–Cipso–Cortho torsion angles within these four compounds. The two diaryl-substituted germanes (o-ButC6H4)2GeBr2 (5) and Mes2GeH2 (6) have also been prepared and structurally characterized, and the absence of a third sterically encumbering aryl group alleviates a significant amount of structural strain in these compounds versus their triaryl-substituted analogues.

Graphical abstractThe four sterically encumbered germanes (o-ButC6H4)3GeX (X = Br, H, Cl, or OH) have been prepared and structurally characterized. The effects of the o-But groups on the geometry at germanium have been investigated. The diaryl-substituted compounds (o-ButC6H4)2GeBr2 and Mes2GeH2 have also been structurally characterized.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights►Triaryl germanes containing a bulky ortho-But group have been synthesized and structurally characterized. ►These molecules are distorted from the ideal tetrahedral geometry and the degree of their distortions has been assessed. ►Two sterically encumbered diaryl germanes have also been prepared and structurally characterized. ►The steric strain in the diaryl germanes is significantly diminished relative to the triaryl germanes.