Synthesis and structural characterization of neutral hexacoordinate silicon(IV) complexes containing salophen and thiocyanato-N ligands

Abstract

The reaction of the H2salophen ligand, 2,2′-((1E,1′E)-(1,2-phenylenebis(azanylylidene))bis (methanylylidene))diphenol, with one molar equivalent of Si(NCS)4, MeSi(NCS)3 (13), or HMeSi(NCS)2 afforded neutral hexacoordinate silicon complexes, which have an-NCS bi-functionality (complex 1) and mono-functionality (complex 14). The reaction of Si(NCS)4 with the H2salophen-type ligand1,1′-((1E,1′E)-(1,2-phenylenebis(azanylylidene))bis(methanylylidene)) bis(naphthalen-2-ol) (H2Noph), afforded the hexacoordinate silicon complex 15, which has an-NCS bi-functionality. Single-crystal X-ray structural and elemental analyses were used to characterize and confirm the structure of the starting material 13 and complexes 1, 14, and 15. The complexes were characterized in solution by 1H, 13C, and silicon-29 nuclear magnetic resonance (29Si NMR) and in the solid state by 29Si cross-polarization/magic angle spinning (CP/MAS) NMR. Because of the poor solubility of complex 1, it was only possible to characterize it in the solid state by 13C and 29Si CP/MAS NMR and in solution by 1H NMR.

Keywords

• 29si nmr spectroscopy
• coordination chemistry
• crystal structure
• hexacoordinate silicon
• salophen ligand
• thiocyanato-n ligands