Synthesis and reactivity of cyclometallated platinum (II) compounds containing [C,N,N 0 ] terdentate ligands: Crystal structures of [PtCl{(CH 3 ) 2 N(CH 2 ) 3 NCH(4-ClC 6 H 3 )}], [PtCl{(CH 3 ) 2 N(CH 2 ) 3 NCH(2-ClC 6 H 3 )}] and [PtCl{(CH 3 ) 2 N(CH 2 ) 3 NCH(3-(CH 3 )C 6 H 3 )}] Alejandro Capape ´ a , Margarita Crespo a, * , Jaume Granell a , Merce ` Font-Bardı ´a b , Xavier Solans b a Departament de Quı ´mica Inorga ` nica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain b Departament de CristalÆlografia, Mineralogı ´a i Dipo ` sits Minerals, Universitat de Barcelona, Martı ´ i Franque `s s/n, 08028 Barcelona, Spain Received 22 April 2005; received in revised form 15 June 2005; accepted 16 June 2005 Available online 10 August 2005 Abstract The reaction of compound cis-[PtCl 2 (dmso) 2 ] with ligands RCHN(CH 2 ) 3 NMe 2 (1a–1h) in which R is a phenyl group containing substituents such as Cl, F, Me, NO 2 and MeO produced compounds [PtCl 2 {(CH 3 ) 2 N(CH 2 ) 3 NCHR}] (2), as mixtures of Z and E isomers. When treated with an equimolar amount of sodium acetate in refluxing methanol compounds 2 gave cyclometallated plat- inum compounds 3 containing a terdentate [C,N,N 0 ] ligand. The obtained compounds were fully characterized including structure determinations for compounds 3a, 3b and 3e. The effects of the substituents in the regioselectivity of the cyclometallation reaction and the reactivity of 3a and 3b with mono and bidentate phosphines were also studied. Ó 2005 Elsevier B.V. All rights reserved. Keywords: Platinum; Cyclometallation; Nitrogen ligands 1. Introduction Cyclometallated compounds, in particular those de- rived from nitrogen ligands, have been a topic of interest in the last years as a consequence of the wide range of their potential applications in many areas [1]. Although this field has been widely studied for bidentate [C,N] li- gands, there are less examples of the cyclometallation of potentially terdentate [C,N,N 0 ] ligands, which benefit from a second N-donor atom [2]. In this work, the reactions of ligands RCHN(CH 2 ) 3 - NMe 2 (R being a substituted aryl ring) with cis- [PtCl 2 (dmso) 2 ] are reported. Analogous potentially terdentate imines RCHN(CH 2 ) 2 NMe 2 have been reported to produce intramolecular C–H bond activa- tion via oxidative addition at platinum substrates such as [Pt(dba) 2 ] [3], [Pt 2 Me 4 (l-SMe 2 ) 2 ] [4] or [PtMe 2 (cod)] [5]. Compound [Pt(l-Cl)(g 3 -2Me-C 3 H 4 )] 2 has also been used for the synthesis of terdentate cycloplatinated derivatives [6]. The recent progress in using the platinum (II) complex cis-[PtCl 2 (dmso) 2 ] as an electrophilic cyclo- metalating agent [7] can be attributed to its easy synthe- sis and high stability. In addition, [N,N 0 ] coordination compounds can be isolated as a prior step to the 0022-328X/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2005.06.038 * Corresponding author. Tel.: +34934039132; fax: +34934907725. E-mail address: margarita.crespo@qi.ub.es (M. Crespo). Journal of Organometallic Chemistry 690 (2005) 4309–4318 www.elsevier.com/locate/jorganchem