The adoption of the beryllium acetate structural motif in zinc oxycarbamates, oxythiocarbamates and oxythiophosphinates Mohammad Azad Malik a , Paul OÕBrien a, * , Majid Motevalli b , Isaac Abrahams b a School of Materials and School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK b Centre for Materials Research, Department of Chemistry, Queen Mary, University of London, Mile End Road, London E1 4NS, UK Received 30 March 2005; accepted 24 June 2005 Available online 15 August 2005 Abstract Zn 4 OL 6 (L = S 2 CNEt 2 ,S 2 PEt 2 and OCNEt 2 ) complexes are readily formed by hydrolysis of the mixed alkylzinc-carbamato, thi- ophophinato or thiocabamato (RZnL) compounds. These oxyzinc complexes all adapt a basic beryllium-acetate-like tetrahedral (l 4 - O)Zn 4 core. The coordination of each zinc atom is completed by bridging carbamato, thiocarbamato or thiophosphinato groups. Disorder is observed in the zinc positions for the two sulfur-containing compounds, with zinc atoms disordered over the eight cor- ners of a cube. The geometry of the core (l 4 -O)Zn 4 moiety is compared with ZnO and a number of related complexes. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Zinc; Carbamato; Thiocarbamato; Thiophosphinato; Zinc oxide; Crystal structure 1. Introduction Dithiocarbamates are used in rubber chemistry and technology, inorganic analysis and in agriculture as fun- gicides. Bis(diethyldithiocarbamato)zinc(II) and alkyl- (dialkyldithiocarbamato)zinc(II) have successfully been used to grow thin films and nanoparticles of ZnS using MOCVD and colloidal methods, respectively [1–4]. The structures of bis(diethyldithiocarbamato)zinc(II) [5] bis(dimethyldithiocarbamato)zinc(II) [6] asymmetric bis(dialkyldithiocarbamato)zinc(II) [7] and alkyl(dial- kyldithiocarbamato)zinc(II) [8] have been reported. Dialkylcarbamato complexes have been prepared by various methods including the reaction of metal chlo- rides with carbon dioxide and a secondary amine [9], the elemental metal with carbon dioxide and a second- ary amine [10] and the insertion of carbon dioxide into a M-NR 2 (R = alkyl, M = metal) bond [11]. We have re- ported the synthesis of a series of diseleno- and dithio- carbamato complexes ([RME 2 CNR 0 2 ] 2 , E = S, Se) [8,12–17] via insertion reaction with CS 2 or CSe 2 . The structural chemistry of these compounds is dominated by the formation of dimeric species. The reaction of CO 2 with alkylzincdiethylamides (RZnNEt 2 ) gave unusual tetrameric species such as [(CH 3 ) 2 Zn 4 (O 2 CN(C 2 H 5 ) 2 ) 6 ] [18] and [(CH 3 ) 4 Zn 4 (O 2 CN(C 2 H 5 ) 2 ) 4 ] [19] which on further reaction with tetramethylethylenediamine or pyr- idine gave monomeric [(Me 2 NCH 2 ) 2 Zn(O 2 CN(C 2 H 5 ) 2 ) 2 ] and dimeric [C 5 H 5 NZn 2 Me(O 2 CN– (C 2 H 5 ) 2 ) 3 ] species, respectively [20,21]. Zn 4 O(O 2 CN-(C 2 H 5 ) 2 ) 6 ] [10] was obtained when elemental zinc was reacted with CO 2 / HNEt 2 . This structure was found to exhibit the beryl- lium acetate structural motif [22], with a (l 4 -O)Zn 4 tetrahedron at the core of the molecule. Dithiophosphinates have many important industrial and agricultural applications, including solvent extrac- tion reagents for metals [23], insecticides and pesticides, flotation agents for mineral ores, and additives to lubri- cant oils [24]. Metal complexes of such ligands have the 0277-5387/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2005.06.033 * Corresponding author. Tel.: +44 161 275 4652; fax: +44 161 275 4616. E-mail addresses: azad.malik@man.ac.uk (M.A. Malik), paul. obrien@manchester.ac.uk (P. OÕBrien). www.elsevier.com/locate/poly Polyhedron 25 (2006) 241–250