Syntheses and structural characterization of dicopper(I) bis(diphenylphosphino)acetylene complexes containing tricyclic, cyclic and linear frameworks

The complexes [Cu2(dppa)3(CH3CN)2][BF4]2 (1) and Cu2(dppa)3(O3SCF3)2 (2) have been prepared in good yields by treating [Cu(MeCN)4][BF4] and [Cu(MeCN)4][O3SCF3], respectively, with Ph2PCtriple bond; length of mdashCPPh2 (abbreviated as dppa) at room temperature. The reaction of 1 with di-2-pyridyl ketone (abbreviated as dpyk) produces [Cu2(dppa)2(dpyk)2][BF4]2 (3), and with 1,1′-bis(diphenylphosphino)ferrocene (abbreviated as dppf) produces [Cu2(dppa)(dppf)2][BF4]2 (4). The molecular structures of 1–4 have been determined by an X-ray diffraction study. Compounds 1 and 2 form a helical Cu2(dppa)3 metallatricycle, compounds 3 forms a Cu2(dppa)2 metallacycle, and compound 4 contains a linear Cu2(dppa) skeleton.