Structural Variety and Multiple Isomerism in l-(Dimethylamino)propyl-2-chalcogenolate and 2-(Dimethylamino)propyl-l-chalcogenolate Complexes of Palladium(II) and Platinum(II):Synthesis,Spectroscopy and Structures

摘要

Isomeric dichalcogenides [Me_2NCH(Me)CH_2E]_2 [(N~nE~(**))_2] and [Me_2NCH_2CH(Me)E]_2 [(NnE~*)_2] (E = S,Se,Te) have been obtained by the reactions of NaSH or M'2E2 (M' = Na or K) with Me_2NCH_2CHMeCl.The former reaction affords mainly (NnE**)_2 (E = S) while from the latter mixtures of (NnE**)_2 and (NnE*)_2 [referred to as (N~nE)_2,E = S,Se,Te] were isolated,the ratios in the mixtures depending on the chalcogen.Reactions of (N~nE)Na with [M_2Cl_2(mu-Cl)_2(PR_3)_2] gave complexes [MCl(N~nE)(PR_3)] (M = Pd or Pt).These chiral,mixed-ligand complexes have been characterised by elemental analysis,IR,UV/Vis and NMR (~1H,~(13)C,~(31)P,~(77)Se,~(125)Te,~( 195)Pt) spectroscopy,and,in part,by X-ray structure analysis.The complexes display a typical pattern of mutually trans-oriented neutral (P and N) and anionic (Cl and E) donor atoms in an approximately square-planar environment.In contrast to the platinum(II) analogues,the X-ray structures of the complexes [PdCl(NnE)(PMePh_2)] (E = S or Se) revealed both a conformational isomerism of the five-membered che-late ring and,for Se,the co-crystallisation of complexes with both the NnE* and NnE* * isomeric ligands.The thermal behaviour of some complexes has been investigated.