Copper(I) acetylide pi-complexes: Synthesis and structure of cluster compound (MeaH)[Cu9Cl8(C CH2OH)(2)(H2O)(2)] (MeaH(+) is monoethanolammonium cation)

The crystals of the cluster compound (MeaH)[Cu9Cl8(C=CCH2OH)(2)(H2O)(2)] (M eaH(+) is the monoethanolammonium cation HOC2H4NH3+)are prepared by ac elec trochemical synthesis and X-ray structurally studied [DARCh autodiffractome ter, lambda MoKalpha, theta/2 theta scan mode, 1705 unique reflections with F greater than or equal to 4 sigma(F), R = 0.029]. The crystals are monocl inic: space group P2(1)/n, Z = 2, a = 16.472(5), b = 10.624(3), c = 6.812(2 ) Angstrom, gamma = 100.90(3)degrees, V = 1171(1) Angstrom(3). In the compl ex, the C=C group of the C-=CH2OH anion is simultaneously coordinated to fi ve Cu(I) atoms: two copper atoms are re-coordinated by the ethynyl group, w hile the other three metal atoms form Cu-C sigma bonds of the acetylide typ e. This results in the centrosymmetric [Cu-9(C=CCH2OH)(2)] clusters, in whi ch the shortest Cu ... Cu distance is 2.507(4) Angstrom.