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Hexacoordinated Group‐14 Elements with Phosphorus Donor Ligands: Syntheses and Structures of Me 2 E[C(PMe 2 ) 2 (SiMe 3 )] 2 (E = Si, Ge, Sn)
Author(s) -
Karsch Hans H.,
Deubelly Brigitte,
Keller Ursula,
Bienlein Fritz,
Richter Roland,
Bissinger Peter,
Heckel Maximilian,
Müller Gerhard
Publication year - 1996
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19961290705
Subject(s) - chemistry , stereochemistry , group (periodic table) , crystallography , main group element , crystal structure , carbon group , group 2 organometallic chemistry , x ray crystallography , molecule , transition metal , biochemistry , organic chemistry , catalysis , physics , diffraction , optics
The dimethyl group‐14 element dihalides Me 2 EX 2 (E = Si, Ge, Sn; X = Cl or Br) react with two equivalents of Li[C(P‐Me 2 ) 2 (SiMe 3 )] to give the cis ‐hexacoordinated complexes Me 2 E[C(PMe 2 ) 2 (SiMe 3 )] 2 (E = Si: 2a , E = Ge: 2b , E = Sn: 2c ), which were characterized spectroscopically and by means of X‐ray structure determinations. Whereas 2a and 2b are isotypic and crystallize in the space group P 2 1 / c , 2c crystallizes in the space group C 2/ c with crystallographic C 2 (2) molecular symmetry. In all cases the diphosphanylmethanide ligands bind in an unisobidentate fashion. For compound 2c , this still can be attributed to the trans influence of the methyl group, but in 2a and 2b clearly borderline cases between hexa‐ and tetracoordination are found. Compound 2b (E = Ge) is much more on the side of tetracoordination than 2a , thus underlining the importance of small polarity differences for the actual coordination number achieved in compounds with relatively unpolar bonds.