Heteropolynuclear Pt(II)–M(I) Clusters with a C∧N∧C Biscyclometalated Ligand

Abstract

The mononuclear complex [(EtO2C-C∧N∧C)Pt(dmpyz)] (1) (dmpyz = 2,5-dimethylpyrazine) has been synthesized by reaction of [(EtO2C-C∧N∧C)Pt(dmso)] (A) with dmpyz in a 1:1 molar ratio in dichloromethane. Complex 1 is the precursor for preparing the homodinuclear complex [{(EtO2C-C∧N∧C)Pt}2(μ-dmpyz)] (2) and the heterotrinuclear clusters [{(EtO2C-C∧N∧C)Pt(dmpyz)}2M]X (M = Cu, X = PF6 (3); M = Ag, X = BF4 (4)). Compounds 1, 2, and 4 were studied by X-ray diffraction methods. In the crystal packing of 1 and 2, the molecules display short intermolecular π···π contacts, which control the solid-state emissive behavior. X-ray study on 4 shows two [Pt2Ag] sandwich-type clusters in the asymmetric unit, both with the two square-planar “(R-CNC)Pt(dmpyz)” moieties stabilized by two Pt → Ag donor–acceptor bonds as well as by η1- and η2-Ag–C interactions. Intramolecular π–π contacts were found between the pyridine rings of the CNC ligands within the same Pt2Ag cluster. 1H and 195Pt NMR studies confirm that the Pt2M cluster...