Oxidative addition reaction of o-quinones to triphenylantimony: novel triphenylantimony catecholate complexes Vladimir K. Cherkasov, Ekaterina V. Grunova, Andrey I. PoddelÕsky * , Georgy K. Fukin, Yury A. Kurskii, Ludmila G. Abakumova, Gleb A. Abakumov G. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Laboratory of the Chemistry of Organoelemental Compounds, 49 Tropinina Street, 603950 Nizhny Novgorod, Russia Received 15 September 2004; accepted 22 November 2004 Available online 7 February 2005 Abstract New catecholate Sb(V) complexes triphenyl(3,6-di-tert-butylcatecholato)antimony(V) Ph 3 Sb(3,6-DBCat) (1) and triphenyl(per- chloroxanthrenecatecholato)antimony(V) Ph 3 Sb( OX Cat Cl )(2) were synthesized by the oxidative addition reaction of corresponding o-quinones (3,6-di-tert-butyl-o-benzoquinone and perchloroxanthrenequinone-2,3) with triphenylantimony. Catecholates 1 and 2 can alternatively be synthesized by reacting the appropriate thallium catecholate with triphenylantimony dichloride. The oxidative addition reaction of an equimolar ratio of 4,4 0 -di-(3-methyl-6-tert-butyl-o-benzoquinone) and triphenylantimony yielded 4-(2- methyl-5-tert-butyl-cyclohexadien-1,5-dion-3,4-yl)-(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V) Ph 3 Sb(Cat-Q) (3); in the case of a 1:2 molar ratio, complex 4,4 0 -di-[(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V)] Ph 3 Sb(Cat-Cat)SbPh 3 (4) resulted. Complexes 1–4 were characterized by IR- and 1 H NMR spectroscopy. Molecular structures of 1, 2 and 4 were determined by X-ray crystallography to be a distorted tetragonal-pyramidal. Ó 2004 Elsevier B.V. All rights reserved. Keywords: Antimony; o-Quinones; Catecholates; Oxidative addition; X-ray diffraction 1. Introduction The chemistry of Sb(V) catecholate complexes is very interesting but little has been published in this field of antimony chemistry. Related scientific literature has shown some methods for preparation of Sb(V) catecho- lates. The reaction of triphenylantimony dichloride and pyrocatechol in the presence of ammonia yielded the partially hydrated product – triphenylantimony catecho- late hemihydrate [Ph 3 Sb(o-O 2 C 6 H 4 )] 2 ÆH 2 O [1]. As Holmes et al. [2] have reported, the reaction of Ph 3 SbCl 2 with naphthalenediol in the presence of Et 3 N leads to the isolation of the six-coordinated hypervalent anionic stiborane [Ph 3 Sb(Cl)(o-O 2 C 10 H 6 )][Et 3 NH]. The same authors synthesized Ph 3 Sb(o-O 2 C 6 H 3 -4-NO 2 ) by the same way from Ph 3 SbCl 2 with 4-nitrocatechol in the presence of Et 3 N [3]. The oxidation of elemental anti- mony by the o-quinones o-O 2 C 6 Y 4 (Y = Cl or Br) in diethyl ether yields the unusual antimony(V) products Sb(o-O 2 C 6 Y 4 ) 2.5 ÆnEt 2 O (Y = Cl, n = 1.5, Y = Br, n = 1) [4]. Authors [4] also have synthesized antimony(III) derivatives Sb(Cat)X (Cat is the substituted catecholate dianion) by the reactions of the same quinones and 3,5- di-tert-butyl-o-benzoquinone with Sb(0) and 0.5X 2 (X = Br or I). The six-coordinate antimony(V) catecho- late complexes of R 3 Sb(Cat)L species reported in [5] were synthesized by the oxidation of R 3 Sb (R = Ph, Me) with tert-butylhydroperoxide in the presence of pyrocatechol and neutral donor ligands L (Py, DMSO 0022-328X/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2004.11.049 * Corresponding author. Tel.: +7(8312)127682; fax: +7(8312)127497. E-mail address: aip@imoc.sinn.ru (A.I. PoddelÕsky). Journal of Organometallic Chemistry 690 (2005) 1273–1281 www.elsevier.com/locate/jorganchem