Heterometallic antimony(V)-zinc and antimony(V)-copper complexes comprising catecholate and diazadiene as redox active centers

1 New bifunctional antimony(V) catecholate Ph 3 Sb(Cat-DAD) with diazadiene group 2 Heterometallic Sb-Zn and Sb-Cu catecholato–1,4-diazabuta-1,3-diene complexes 3 The redox-properties of heterometallic Sb-Zn catecholato-diazadiene complex Triphenylantimony(V) catecholate of the type Ph 3 Sb(Cat-DAD) ( 2 ) based on bifunctional 4-(4-(2,6-diisopropylphenyl)-2,3-dimethyl-1,4-diazabuta-1,3-diene-1-yl)-3,6-di- tert -butyl- o -benzoquinone, Q-DAD, ( 1 ) was applied for a synthesis of new bimetallic antimony(V)-zinc(II) and antimony(V)-copper(I) catecholato-diazadiene complexes Ph 3 Sb(Cat-DAD)ZnI 2 ( 3 ) and Ph 3 Sb(Cat-DAD)Cu 2 Cl 2 ( 4 ), respectively. In Sb(V)-Zn(II) complex 3 , the acceptor properties of a coordinated DAD group decrease (E Red 1/2 = - 0.93 V vs. Ag/AgCl/KCl(sat.) for 3 in contrast to - 0.55 V for 1 ) due to the presence of a more donor catecholate group in the complex 3 as compared to o-quinone in 1 . In the accordance with cyclic voltammetry both redox-active centers (DAD and Cat) in 3 are available for redox transformations. The interaction of 2 with CuCl 2 is accompanied by the oxidation of catecholate centers by Cu(II) in DAD complex and, as a result, complex 4 - a heterometallic Sb(V)-Cu(I) complex - was formed. The crystal structures of 3 •2THF, ( 4 ∙MeCN)•1.5CH 2 Cl 2 and o-quinone 1 have been determined by single-crystal X-ray analysis. Synopsis New antimony(V) catecholate complex bearing 1,4-diazabuta-1,3-diene as an additional redox-active center was synthesized. Complex serves as a source for novel heterometallic compounds with redox-active ligands. Zinc and copper complexes of the type Ph 3 Sb(Cat-DAD)ML have been synthesized and characterized. Synthesis of copper complex is accompanied by redox reaction between Cu(II)-DAD center and triphenylantimony(V) catecholato moiety.