Dianion of pyrrole-2-N-(o-hydroxyphenyl)carbaldimine as an interesting tridentate (ONN) ligand system in hypercoordinate silicon complexes

摘要

The tridentate title ligand was found to act as an (NeqNaxOeq) = (N-amide,N-imine,O-phenolate) ligand as well as an (NaxNeqOax) ligand in pentacoordinate silicon complexes depending on the substituents at the Si atom. Its two notably different coordination modes in (NeqNaxOeq)Si(CH2)(3) and (NaxNeqOax)SiPhMe were studied with X-ray structure analysis as well as Si-29 CP/MAS NMR spectroscopy together with quantum chemical calculations of geometry and NMR chemical shielding tensors.