SYNTHESIS AND CRYSTAL-STRUCTURES OF [CU-2(MU-(PH(2)P)(2)PY)(3)][PF6](2) AND CU-2(MU-(PH(2)P)(2)PY)(2)(ETA(2)-BIPY)(2)][PF6](2) [(PH(2)P)(2)PY=2,6-BIS(DIPHENYLPHOSPHINO)PYRIDINE, BIPY=2,2'-BIPYRIDINE]

Treatment of [Cu(MeCN)(4)]PF6 in acetonitrile with 2,6-bis(diphenylpho sphino)pyridine [(Ph(2)P)(2)py] afforded a colourless crystalline mate rial characterised as [Cu-2{mu-(Ph(2)P)(2)py}(3)][PF6](2). An X-ray di ffraction study confirmed that the three ligands bridge the two copper atoms bonding solely through the phosphorus atoms, each copper being trigonally coordinated; a cavity thus exists in the centre of the dinu clear dication bounded by the nitrogen donor atoms, the Cu...Cu distan ce and the diameter of the cavity being 4.744(2) and ca 4.9 Angstrom, respectively. Measurements of the solution emission spectra of [Cu-2{m u-(Ph(2)P)(2)py}(3)][PF6](2), in the presence and absence of Cu+ and A g+ ions suggest that these ions are trapped in the cavity on their add ition to an acetonitrile solution of the complex. Addition of (Ph(2)P) (2)py to [Cu(eta(2)-bipy)(MeCN)(2)]PF6 (bipy = 2,2'-bipyridyl) in acet one afforded a yellow crystalline solid characterised as u-2{mu-(Ph(2) P)(2)py}(2)(eta(2)-bipy)(2)][PF6](2). A crystal structure determinatio n revealed that the two copper atoms are bridged by the two (Ph(2)P)(2 )py ligands bonding solely through the phosphorus atoms, with the irre gular tetrahedral coordination at each copper being completed by the n itrogen atoms of the chelating bipyridyl ligands. The Cu...Cu distance is 6.806(2) Angstrom. Copyright (C) 1996 Elsevier Science Ltd