Interaction of Organoplatinum(II) Complexes with Monovalent Coinage Metal Triflates

The organoplatinum(II) complexes [(NN)PtMe2] and [(NN)PtPh2] (NN = ArNC(Me)C(Me)NAr, Ar = 2,6-dichlorophenyl) can act as donor ligands for copper(I) and silver(I) triflates, affording a series of homo- and heteroleptic complexes which were characterized by X-ray diffraction. [(NN)PtMe2] binds to the coinage metals through short, ligand-unsupported d−d10 contacts that are best described as Pt→M dative bonds (M = Cu, Ag), in which the dz2 orbital of the square-planar Pt(II) center donates electron density to the Lewis-acidic metal. Spectroscopic studies in solution and DFT calculations corroborate this description. [(NN)PtPh2] binds preferentially by η1 or η2 complexation of the ipso carbon atoms of the phenyl groups to the coinage metal, affording homoleptic complexes {[(NN)PtPh2]2M}+{TfO}− in the solid state. The 1:1 adducts of formula {[(NN)PtPh2]M(OTf)}n (M = Cu, n = 1; M = Ag, n = 2) are observed in solution, and a 1:2 adduct of formula {[(NN)PtPh2]Ag2(OTf)2(C6H6)}n was characterized in the solid state, showing that unsupported Pt→M bonds are also accessible for [(NN)PtPh2]. The thermolyses of the complexes [(NN)PtMe2]MOTf in benzene affords moderate yields of [(NN)PtPh2] through an oxidatively induced double C−H activation process.

有机铂(II)配合物[(NN)PtMe2]和[(NN)PtPh2]（NN = ArNC(Me)C(Me)NAr，Ar = 2,6-二氯苯基）可作为铜(I)和银(I)三氟化物的供体配体，形成一系列同配和异配配合物，这些配合物通过X射线衍射进行了表征。[(NN)PtMe2]通过与贵金属的短、非配体支持的d−d10接触与贵金属结合，这种接触最好描述为Pt→M配位键（M = Cu, Ag），其中正方形平面Pt(II)中心的dz2轨道向路易斯酸性的金属捐赠电子密度。溶液中的光谱学研究及DFT计算证实了这一描述。[[(NN)PtPh2]与苯基的间位碳原子通过η1或η2配位优先与贵金属结合，在固态中形成同配配合物{[(NN)PtPh2]2M}+{TfO}−。在溶液中观察到1:1加合物[(NN)PtPh2]M(OTf)n（M = Cu，n = 1；M = Ag，n = 2），在固态中表征了1:2加合物[(NN)PtPh2]Ag2(OTf)2(C6H6)n，表明[(NN)PtPh2]的非配位Pt→M键同样可以形成。在苯中[(NN)PtMe2]MOTf配合物的热分解通过氧化诱导的双C−H活化过程，提供了中等产率的[(NN)PtPh2]。