Note Stabilization of the (g 4 -COD)Pt-fragment (COD = g 2 ,g 2 -cyclo- octa-1,5-diene) by a bistriazenide: Synthesis and X-ray structural characterization of [(g 4 -COD)Pt(NNN-Ph) 2 C 6 H 4 ], a neutral 1,2-bis(phenyltriazenido)benzene complex of platinum(II) Manfredo Ho ¨ rner a, * , Gelson Manzoni de Oliveira a, * , Julieta Saldanha de Oliveira a , Wagner Magno Teles b,1 , Carlos Alberto Lombardi Filgueiras c , Johannes Beck d a Departamento de Quı ´mica, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil b Departamento de Quı ´mica, ICE, Universidade Federal de, Juiz de Fora, 36036-330 Juiz de Fora, MG, Brazil c Instituto de Quı ´mica, Universidade Federal do Rio de, Janeiro, 21949-900 Rio de Janeiro, RJ, Brazil d Institut fu ¨ r Anorganische Chemie der Rheinischen, Friedrich-Wilhelms-Universita ¨ t, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany Received 1 September 2005; received in revised form 13 September 2005; accepted 13 September 2005 Available online 13 October 2005 Abstract After exchange of Cl against NO 3 by reaction with AgNO 3 [(COD)PtCl 2 ] reacts with the sodium salt of 1,2-bis(phenyltriazene)ben- zene to give [(g 4 -COD)Pt(NNN-Ph) 2 C 6 H 4 ], the first example of a p-fragment of platinum(II) stabilized by two symmetrical triazenide chains. The new complex belongs to the monoclinic space group C2/c and corroborates the ability of the (COD)Pt fragment to be stabilized by bidentate ligands. The odd flying dragon structure of the title compound retains the C 2v symmetry of the free anion 1,2-bis(phenyltriazenide)benzene. Ó 2005 Elsevier B.V. All rights reserved. Keywords: Triazenes; Triazenide-complexes; (COD)Pt-fragment 1. Introduction Organoplatinum(II) complexes [(COD)Pt(R) 2 ] (R = al- kyl or aryl) are well known since decades and have been widely used as precursors for mono- and polynuclear orga- nometallic platinum(II) compounds [1–10]. They are also of interest for the generation of organoplatinum reaction centres on catalyst surfaces for heterogeneous catalysis [11] or as potential precursors for chemical vapour deposi- tion (CVD) of platinum [12]. In contrast, with exception of some classical examples like [(COD)PtCl 2 ] [13], a very small number of complexes is known in which the (COD)Pt fragment is stabilized by an heteroatom. There are only six crystallographically characterized [14–19] examples of compounds with two nitrogen atoms acting as co-ligands, like for example (g 2 ,g 2 -cyclo-octa-1,5-diene)-bis(3,5-bis(tri- fluoromethyl)pyrazole-N)-platinum(II) [14] and (N,N 0 -1, 2-phenylenebis(benzenesulfonamido))(g 2 ,g 2 -cyclo-octa-1,5- diene)-platinum(II) [15]. None of the described examples exhibits a triazene chain as co-ligand. On the basis of their structures and biological activity [20], triazenes are well important and interesting substances. As ligands, the N–N–N moieties – with single or twofold nitrogen chains, neutral or anionic (triazenides) – can act as mono, bidentate or chelate ligands, showing a remarkable ability to support the stereochemical requisites of a wide variety of metal transition complexes [21–23]. 0022-328X/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2005.09.018 * Corresponding authors. Tel.: +55 55 3220 8056; fax: +55 55 3220 8031. E-mail addresses: hoerner@smail.ufsm.br (M. Ho ¨ rner), manzoni@ quimica.ufsm.br (G.M. de Oliveira). 1 In memoriam. www.elsevier.com/locate/jorganchem Journal of Organometallic Chemistry 691 (2006) 251–254