STABILIZATION OF A Y-SHAPED CU-I COORDINATION IN [CUPT2(PPH(3))(5)(MU(3)-S)(2)]PF6 BY PT-2 (PPH(3))(4)(MU-S)(2) AND ITS EXPANSION TO A PENTANUCLEAR AGGREGATE[CU(PT-2(PPH(3))(4)(MU(3)-S)(2))(2)] PF6-CENTER-DOT X-RAY CRYSTAL-STRUCTURE OF [CUPT2(PPH(3))(5)(MU(3)-S)(2)]PF6

Addition of Pt-2(PPh(3))(4)(mu-S)(2), 1, to an equimolar quantity of C u(NO3)(PPh(3))(2) gave [CuPt2(PPh(3))(5)(mu(3)-S)(2)]NO3, 2a, which re adily reacted with NH4PF6 giving [CuPt2(PPh(3))(5)(mu(3)-S)(2)]PF6, 2b . Further addition of a molar equivalent of 1 to 2b gave rise to a pen tanuclear {CuPt4} complex of [Cu{Pt-2(PPh(3))(4)(mu(3)-S)(2)}(2)]PF6, 3. Complex 3 was also obtained from the direct 2:1 addition of 1 to [C u(CH3CN)(4)]PF6. Complexes 2 and 3 have been characterized by IR and P -31-{H-1} NMR spectroscopy and in the case of 2b single crystal X-ray crystallography. The geometry of Cu-1 in 2b is three-coordinate and Y- shaped. It represents the first crystallographically characterized mix ed-metal complex of 1 with a trigonal-planar heterometal. The unexpect edly short non-bonding Cu-Pt distances (av. 2.869(4) Angstrom) are ass ociated with a more open {Pt2S2} butterfly core (theta 137.5(5)degrees ). Some theoretical aspects of these geometric peculiarities are discu ssed. Copyright (C) 1996 Elsevier Science Ltd