Short-Bite PNP Ligand-Supported Rare Tetranuclear [Cu₄I₄] Clusters: Structural and Photoluminescence Studies

The group 11 metal complexes of two short-bite PNP ligands, C6H5N­{P­(OC6H3(OMe-o)­(C3H5-p))2}2 (1) and C6H5N­{P­(OC6H4C3H5-o)2}2 (2), are described. Ligands 1 and 2 on treatment with copper­(I) halides (CuX, X = Cl, Br, or I) yielded dimeric, tetranuclear complexes of the type [(CuX)4{C6H5N­(PR2)2}] (R = OC6H3(OMe-o)­(C3H5-p), X = Cl (3), Br (5), I (7); R = OC6H3(C3H5-o), X = Cl (4), Br (6), I (8)). The chloro-derivative 3 adopts the common “stair-step” geometry, whereas the bromo- and iodo-derivatives form Cu4 square planes with two tetracoordinating μ4-halides capping the axial positions to give octahedral geometry with two other μ2-halides being in the plane. The iodo-derivative 8 with a very short Cu–Cu distance of 2.568 Å shows photoluminescence in the solid state.本文报道了两种短咬合PNP配体（PNP ligand），即C₆H₅N{P(OC₆H₃(OMe-o)(C₃H₅-p))₂}₂（记为配体1）与C₆H₅N{P(OC₆H₄C₃H₅-o)₂}₂（记为配体2）的第11族金属配合物。将配体1与2与卤化铜(I)（CuX，X=Cl、Br或I）反应，可得到构型为[(CuX)₄{C₆H₅N(PR₂)₂}]的二聚四核配合物：当R=OC₆H₃(OMe-o)(C₃H₅-p)时，X分别为Cl（产物3）、Br（产物5）、I（产物7）；当R=OC₆H₃(C₃H₅-o)时，X分别为Cl（产物4）、Br（产物6）、I（产物8）。氯代衍生物3采用常见的“阶梯状”几何构型，而溴代与碘代衍生物则形成Cu₄正方形平面结构，以两个四配位μ₄-卤化物盖帽轴向位置，构成八面体几何构型，另有两个μ₂-卤化物处于平面内。其中，具有2.568 Å极短Cu-Cu距离的碘代衍生物8在固态下表现出光致发光特性。