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Comparative chemistry of isolable divalent compounds of silicon, germanium, and tin
Author(s) -
Kira Mitsuo,
Ishida Shintaro,
Iwamoto Takeaki
Publication year - 2004
Publication title -
the chemical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.61
H-Index - 78
eISSN - 1528-0691
pISSN - 1527-8999
DOI - 10.1002/tcr.20019
Subject(s) - chemistry , carbon group , steric effects , main group element , divalent , trimethylsilyl , ligand (biochemistry) , silylene , germanium , crystallography , substituent , tin , monomer , molecular orbital , stereochemistry , group (periodic table) , molecule , silicon , medicinal chemistry , transition metal , organic chemistry , biochemistry , polymer , receptor , catalysis
Recent studies of the synthesis, structures, spectroscopic properties, and reactions of a series of isolable metallylenes (R 2 E:, E = Si ( 1 ), Ge ( 2 ), and Sn ( 3 ); R 2 = 1,1,4,4‐tetrakis(trimethylsilyl)butane‐1,4‐diyl) are summarized. Because these group‐14 metallylenes bear the same helmet‐like ligand, a straightforward discussion of the element‐dependence of the intrinsic properties of the group‐14 element divalent compounds is possible. All these metallylenes were monomeric both in solution and in the solid state, indicating the effective steric protection by the ligand against dimerization. A small σπ conjugation between CSi(substituent) σ orbitals and the vacant n p z orbitals of divalent atoms in R 2 E: exists and the extent decreases in the order E = Si > Ge > Sn, as evidenced by UV‐vis and NMR spectroscopies and X‐ray crystallography. However, the extent of the σπ conjugation in metallylenes 1–3 was much smaller than the electron‐donating effects of neighboring nitrogen atoms in known stable cyclic diamino‐substituted metallylenes, and hence metallylenes 1–3 are regarded as the least electronically perturbed. Comparative studies of the unique reactions among these metallylenes are also discussed. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 243–253; 2004: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20019