IMINOQUINONE COORDINATION TO COPPER(I) IN THE [CU(PHENOXBQ)(MU-CL)](2) DIMER

The addition of 2,4,6,8-tetra-tert-butylphenoxazin-1-one (PhenoxBQ) to an acetonitrile solution of CuCl leads to the formation of the [Cu(Ph enoxBQ) (mu-Cl)](2) dimer. Structural characterization on crystals of the dimer obtained by recrystallization from dichloromethane (triclini c, P (1) over bar, a=10.559(1), b=11.914(3), c=13.530(4) Angstrom, alp ha=85.55(2), beta=74.57(2), gamma=75.52(2)degrees V=1588.5(6) Angstrom (3), Z=1, R=0.079) has shown that the coordination geometry about the metals is tetrahedral. The Cu-Cu separation of 2.826(1) Angstrom and t he Cu-Cl lengths of 2.215(3) and 2.289(2) Angstrom are unusually short among chloro-bridged Cu(I) dimers. Addition of PhenoxBQ to CuCl2, res ults in the formation of [Cu(PhenoxBQ)Cl-2](2), also formulated as a d imer on the basis of its magnetic and electrochemical properties. Both dimers show the four-membered redox series that appears characteristi cally for complexes containing two PhenoxBQ or PhenoxSQ ligands. In th e case of [Cu-I(PhenoxBQ)Cl](2) an oxidation at + 1.043 V (versus NHE) has been assigned as the Cu(I)/Cu(II) couple associated with oxidatio n of one metal ion of the dimer.