Stable Silicon(0) Compound with a Si=Si Double Bond

• Published in: Science (American Association for the Advancement of Science) Vol. 321; no. 5892; pp. 1069 - 1071
• Main Authors: Wang, Yuzhong, Xie, Yaoming, Wei, Pingrong, King, R. Bruce, Schaefer, Henry F. III, von R. Schleyer, Paul, Robinson, Gregory H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 22.08.2008; The American Association for the Advancement of Science
• Subjects: Atoms; Carbenes; Chemical bonding; Chemical bonds; Chemistry; Condensed matter: structure, mechanical and thermal properties; Crystal binding; cohesive energy; Crystalline state (including molecular motions in solids); Exact sciences and technology; Hexanes; Ligands; Metals; Molecular orbitals; Molecules; Nuclear magnetic resonance; Oxidation; Physics; Silicon; Structure of solids and liquids; crystallography; Double bonds; Frontier orbital; Molecular structure; Silicon complexes; Density functional method; Carbenes; Bond lengths
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1160768

Dative, or nonoxidative, ligand coordination is common in transition metal complexes; however, this bonding motif is rare in compounds of main group elements in the formal oxidation state of zero. Here, we report that the potassium graphite reduction of the neutral hypervalent silicon-carbene complex L:SiCl₄ {where L: is:C[N(2,6-Pri₂-C₆H₃)CH]₂ and Pri is isopropyl} produces L:(Cl)Si-Si(Cl):L, a carbene-stabilized bis-silylene, and L:Si=Si:L, a carbene-stabilized diatomic silicon molecule with the Si atoms in the formal oxidation state of zero. The Si-Si bond distance of 2.2294 ± 0.0011 (standard deviation) angstroms in L:Si=Si:L is consistent with a Si=Si double bond. Complementary computational studies confirm the nature of the bonding in L:(Cl)Si-Si(Cl):L and L:Si=Si:L.