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Novel Hexacoordinate Diorganosilanes with Salen‐Type Ligands: Molecular Structure versus 29 Si NMR Chemical Shifts
Author(s) -
Wagler Jörg,
Böhme Uwe,
Brendler Erica,
Blaurock Steffen,
Roewer Gerhard
Publication year - 2005
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200500076
Subject(s) - hexacoordinate , chemistry , octahedron , ligand (biochemistry) , coordination sphere , crystallography , atom (system on chip) , stereochemistry , nmr spectra database , chemical shift , silicon , crystal structure , spectral line , biochemistry , physics , receptor , embedded system , organic chemistry , astronomy , computer science
Starting from diorganodichlorosilanes and the tetradentate salen‐type ligand 1 o ‐HO‐ p ‐OMe‐C 6 H 3 ‐C(Ph)=N‐(CH 2 ) 2 ‐N=C(Ph)‐C 6 H 3 ‐ p ‐OMe‐ o ‐OH eight hexacoordinate diorganosilanes RR′Si[ o ‐O‐ p ‐OMe‐C 6 H 3 ‐C(Ph)=N‐(CH 2 ) 2 ‐N=C(Ph)‐C 6 H 3 ‐ p ‐OMe‐ o ‐O] [R, R′= Ph, Me ( 2a ); Ph, Et ( 2b ); Ph, Cy ( 2c ); Vi, Me ( 2d ); Ph, Vi ( 2e ); Ph, Ph ( 2f ); Me, Me ( 2g ); ‐(CH 2 ) 3 ‐ ( 3 )] were synthesized. In all these complexes the silicon atom is situated in a distorted octahedral coordination sphere. The organic substituents at the Si atom in 2a, 2b, 2e, 2f, and 2g are trans ‐positioned. Referring to the almost planar coordination sphere provided by the tetradentate azomethine ligand in complexes 2a ‐ 2g , the mer‐fac ‐configuration, i.e. an all‐cis arrangement of the O, C and N donor atoms in 3 , is especially remarkable. As proven by 29 Si CP/MAS spectra as well as Si chemical shift tensor calculations, in compounds 2a, 2f and 2g the silicon atom is most shielded in the direction of the axially arranged Si‐C bonds.