XAPHENYLCYCLOHEXASILOXANEHEXAOLATO)-HEXACOPPER(II) DIMETHYLFORMAMIDE SOLVATE

The sandwich-like title complex, hexakis(dimethylformamide)-1 kappa O, 2 kappa O,3 kappa O,4 kappa O,5 kappa O,6 kappa O-bis[2,4,6,8,10,12-he xaphenylsiloxane-2, 4, 6, 8, 10, 12-hexaolato (6-)-1:2 kappa(2)O(1),2: 3 kappa(2)O(2),3:4 kappa(2)O(3),4:5 kappa(2)O(4),5:6 kappa(2)O(6)]-hex acopper(II) tetrakis (dimethylformamide) solvate, [Cu-6(C3H7NO)(6){(C6 H5)(6)O12Si6}(2)].4C(3)H(7)NO, is comprised of two regular crown-shape d macrocyclic hexadentate organosiloxanolate ligands chelating a flat Cu-6 hexagon, as in the ethanol-solvated analogue investigated previou sly. The title complex has a more distorted shape than the trigonal et hanol-solvated analogue, being slightly side-oblated, but still contai ns a large empty inner channel accessible by small molecules (the diam eter of the free cross-section being about 2.5 Angstrom). Each Cu-II i on has a square-pyramidal coordination comprised of four basal siloxan olate O atoms and an apical dimethylformamide (DMFA) molecule (coordin ated through its carbonyl group). The average bond lengths are Cu-O(Si ) 1.964(11) and Cu-O(DMFA) 2.215(10) Angstrom. The structure contains four additional DMFA molecules per complex unit, linked by weak C-H .. . O hydrogen bonds. Unexpectedly, the C=O bond length is longer [1.248 (10) and 1.255(9) Angstrom] in the uncoordinated DMFA molecules than i n the coordinated molecules [1.214-1.227(7) Angstrom].