HETEROPOLYMETALLIC COMPLEXES OF 1,1'-BIS (DIPHENYLPHOSPHINO)FERROCENE, DPPF .8. X-RAY CRYSTAL-STRUCTURE OF COPPER(I) DIMER [MU-DPPF)(CU(DPPF))2](CLO4)2

The dimeric Cu(I) complex [(mu-dppf)(Cu(dppf))2](ClO4)2, where dppf is Fe(eta5-C5H4)P(C6H5)2)2, has been characterized by single-crystal X-ray crystallography. The complex crystallizes in the triclinic space group P1 (no. 2) with unit cell parameters a = 21.852(5), b = 18.063(5), c = 14.867(5) angstrom, alpha = 114.32(3), beta = 109.87(3), gamma = 82.84(3)-degrees. The structure was refined to R = 5.40% based on 5562 observed reflections. Two crystallographically independent, structurally equivalent, units were observed in the structure. The structure consists of the centrosymmetric dimeric [(mu-dppf) (Cu(dppf))2]2+ cations and ClO4- anions. The copper atoms are three-coordinate being trigonally bonded to one chelating and one bridging ligand. The P-Cu-P bond angles for the chelating dppf ligand are 11 1. 1(2)-degrees and 11 1.3(2)-degrees, while the P-Cu-P angles linking different dppf molecules range from 123.9(2) to 124.2(2)-degrees. Cu-P bond distances fall within normal ranges lying between 2.265(5) and 2.285(4) angstrom, with the values for the chelating dppf being slightly larger than those observed for the bridging ligand. The cyclopentadienyl rings are exactly staggered and parallel, and the P atoms 180' opposed in the bridging dppf, while the rings maintain an approximately staggered configuration and are inclined by 1.6-degrees to each other with the P atoms being 39.5-degrees apart in the chelating ligand. A steric control of the stereochemistry of the monomer fragment of the dimer complex is suggested.