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Transition Metal Complexes with Sulfur Ligands, Part 119 . Synthesis of Water Soluble Fe and Ru Complexes with Novel Multidentate Thioether Thiolate Ligands Containing Carboxylate Substituents
Author(s) -
Sellmann Dieter,
Becker Thomas,
Knoch Falk
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.19961290507
Subject(s) - chemistry , thioether , diastereomer , denticity , alkylation , ligand (biochemistry) , medicinal chemistry , transition metal , stereochemistry , carboxylate , dithiol , metal , organic chemistry , catalysis , biochemistry , receptor
In search of water soluble transition metal complexes with sulfur dominated coordination spheres that model key reactions of nitrogenases, the benzenedithiol derivatives ‘CO 2 HS 2 ’‐H 2 ( 1 ) and ‘CO 2 Me‐S 2 ’‐H 2 ( 2 ) were synthesized as precursors for multidentate sulfur ligands. The template alkylation of 2 by C 2 H 4 Br 2 at [Fe(CO) 2 ] fragments yielded a mixture of two diastereomeric C 2 symmetrical [Fe(CO) 2 (‘CO 2 Me‐S 4 ’)] complexes ( 4a and 4b ), which were separated by crystallization. The hydrolysis of the mixture of the diastereomers 4a and 4b led to the isomerically pure tetradentate thioether thiol ligand ‘CO 2 Me‐S 4 ’‐H 2 ( 5 ) proving the regioselectivity of the template alkylation of the asymmetrical dithiol 2 . The C 1 symmetrical [Fe(‘CO 2 Me‐S 2 ’) 2 ] 2‐ anion is an intermediate of the template alkylation and was isolated as (AsPh 4 ) 2 [Fe(‘CO 2 Me‐S 2 ’ 2 ] ( 11 ), 4a, 5 and 11 were characterized by X‐ray structural analysis. Saponification of the methyl ester groups of 5 yielded ‘CO 2 H‐S 4 ’‐H 2 ( 7 ). Treatment of 7 with FeCl 2 · 4 H 2 O in the presence of CO and LiOMe gave a mixture of two C 2 symmetrical and water soluble diastereomers of Li 2 [Fe(CO) 2 (‘CO 2 ‐S 4 ’)] ( 8 ). Upon treatment with [RuCl 2 (PPh 3 ) 3 ] 7 yielded isomerically pure [Ru(PPh 3 ) 2 ‐(‘CO 2 H‐S 4 ’)] ( 9 ). 9 also exhibits C 2 symmetry and could be reversibly deprotonated to form the water soluble complex K 2 [Ru(PPh 3 ) 2 (‘CO 2 ‐S 4 ’)] ( 10 ). Treatment of (NBu 4 ) 2 (‘CO 2 MeS 2 ’) with “Ru(NO)Cl 3 ” led to isomerically pure (NBu 4 )[Ru(NO)(‘CO 2 Me‐S 2 ’) 2 ] ( 12 ).