Antiferromagnetic complexes with metal-metal bonds Part XXIX. Synthesis and molecular structures of heterochalcogenide binuclear complex [pi-(CH3C5H4)Cr(mu-SPh)](2)Se and trinuclear mixed-metal cluster [pi-(CH3C5H4)(2)Cr-2(mu-SPh)](mu(3)-S)(mu(3)-Se)Co(CO)(2)

[Cp'Cr(CO)(2)(mu -SPh)](2) (Cp'=pi -CH3C5H4) obtained by the interaction of [Cp'Cr(CO)(3)](2) with Ph2S2 was decarbonylated to [Cp'Cr(CO)(mu -SPh)](2) which reacted with Se powder to give the antiferromagnetic complex [Cp'Cr( mu -SPh)](2)(mu -Se) (mu (eff) reduces from 0.79 down to 0.30 muB in the 29 0-80 K temperature range with exchange parameter - 2J = 552 cm (-1)), chara cterized by X-ray diffraction analysis (Cr-Cr 2.730, Cr-S 2.635, Cr-Se 2.40 1-2.395 Angstrom, Cr-Se-Cr 69.4 degrees). Another route to [Cp'Cr(mu -SPh)] (2)(mu -Se) was the interaction of [Cp'Cr(CO)(3)](2)(mu -Se) with Ph2S2. Tr eatment of [Cp'Cr(mu -SPh)](2)(mu -Se) with Co-2(CO)(8) results in the mixe d-metal heterochalcogenide cluster Cp-2'Cr-2(mu -SPh)(mu (3)-S)(mu (3)-Se)C o(CO)(2) characterized by X-ray analysis (Cr-Cr 2.624, Cr-Co 2.602-2.625, C r-mu (3)-S 2.32, Co-mu (3)-S 2.23, Cr-mu (3)-Se 2.43, Co-mu (3)-Se 2.30, Cr -mu -S-ph 2.32 Angstrom). The cluster is antiferromagnetic (mu (eff) reduce d from 0.73 down to 0.45 muB in the 290-80 K temperature range with exchang e parameter - 2J= 688 cm(-1)). (C) 2000 Published by Elsevier Science B.V. All rights reserved.