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Synthesis and Structures of Homoleptic Methyl‐ and Phenylthiomethylaluminium Complexes [Al(CH 2 SR) 3 ](R = Me, Ph)
Author(s) -
Rüffer Tobias,
Bruhn Clemens,
Rusanov Eduard,
Nordhoff Karsten,
Steinborn Dirk
Publication year - 2002
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 - 10.1002/1521-3749(200202)628:2<421::aid-zaac421>3.0.co;2-q
Subject(s) - homoleptic , chemistry , crystallography , crystal structure , trigonal bipyramidal molecular geometry , ligand (biochemistry) , lone pair , sulfur , stereochemistry , metal , molecule , organic chemistry , biochemistry , receptor
Sulfur‐substituted methylmercury compounds [Hg(CH 2 SR) 2 ]( 1a, R = Me; 1b, R = Ph ) react with aluminium amalgam in refluxing toluene with transmetallation to give homoleptic tris(thiomethyl)aluminium complexes [Al(CH 2 SR) 3 ]( 2a, R = Me; 2b, R = Ph ) (degree of conversion: >80%, isolated yields: 2a 63%, 2b 41%). Their identities were confirmed by NMR spectros‐copy ( 1 H, 13 C) and X‐ray crystal structure analyses. In crystals of compound 2a the aluminium atoms possess a trigonal‐bipyramidal arrangement with the coordination polyhedron defined by three carbon and two sulfur atoms. Two of the three CH 2 SMe ligands are bridging ligands (μ‐η 2 ; 1k C :2k S ), the third one is terminal bound (η 1 ; k C ). The structure is polymeric. Crystals are threaded by helical chains built up of six‐membered Al 2 C 2 S 2 rings. Crystals of 2b are built up of centrosymmetrical dimers with six‐membered Al 2 C 2 S 2 rings having bridging CH 2 SPh ligands (μ‐η 2 ; 1k C :2k S ). On each Al atom two terminal (η 1 ; k C )CH 2 SPh ligands are bound. They exhibit quite different Al‐C‐S angles (116.7(4) and 106.5(3)?). Similar values (114.32115.7? and 109.52109.9?) were found in ab initio calculations of model compounds [{Al(CH 2 SR) 3 } 2 ]( 3a, R=H; 3b, R=Me; 3c, R=CH=CH 2 ). A conformational energy diagram for rotation of one of the terminal CH 2 SH ligand in the parent compound 3a around the Al‐C bond is discussed in terms of repulsive interactions of lone electron pairs of sulfur atoms.