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Monofunktionelle tetraedrische Zink‐Komplexe L 3 ZnX [L 3 Tris(pyrazolyl)borat]
Author(s) -
Alsfasser Ralf,
Powell Anne K.,
Vahrenkamp Heinrich,
Trofimenko Swiatoslaw
Publication year - 1993
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.19931260320
Subject(s) - chemistry , zinc , tris , medicinal chemistry , hydrolysis , ligand (biochemistry) , stereochemistry , crystal structure , crystallography , organic chemistry , biochemistry , receptor
Monofunctional Tetrahedral Zinc Complexes L 3 ZnX [L 3 Tris(pyrazolyl)borate] The pyrazolyl borates K[HBpz 3 *] (abbreviated KL 3 , pz*3‐phenyl‐, 3‐tolyl‐, 3‐anisyl‐3,5‐diphenyl pyrazolyl) react with zinc salts ZnX 2 (XCl, Br, I, NO 3 ) to form the mononuclear neutral tetrahedral zinc complexes L 3 ZnX ( 1 – 4 ). The corresponding alkylzinc complexes L 3 ZnR ( 5 – 8 ; RMe, Et, t Bu, Ph) result either from L 3 ZnCl and LiR or from ZnEt 2 and KL 3 . These alkylzinc compounds are remarkably stable towards oxidation and hydrolysis. For specific cases the reaction of L 3 ZnR with carboxylic acids is found to yield the carboxylates L 3 ZnOCOR ( 9, 10 ), and likewise with thioacetic acid to yield the thioacetates L 3 ZnSCOMe ( 11 ). Facile cleavage of L 3 ZnR with thiols and selenophenol produces the thiolates L 3 ZnSR ( 12, 13 ) and the selenolates L 3 ZnSePh ( 14 ). The complexes L 3 Zn t Bu which are the most reactive of the alkylzinc compounds are cleaved by H 2 O, H 2 S, NH 3 and various OH and NH compounds with formation of the bis(ligand) complexes Zn(L 3 ) 2 ( 15 ). Crystal structure determinations of one L 3 ZnX complex each for XNO 3 ( 4a ), CH 3 ( 5a ), SCOMe ( 11a ), and SEt ( 12a ) confirm the nature of the compounds and the relation of 4a and 12a to the active centers of zinc‐containing enzymes.