Synthesis, structural characterization and Hirshfeld surface analysis of copper(I) complexes containing hemilabile-ferrocenylbisphosphine [Fe{C5H4P(C6H4CH2NMe2-o)2}2]

The reactions of ferrocenylbisphosphine, [Fe{C5H4P(C6H4CH2NMe2-o)2}2] (1) comprising dangling amine functionalities with CuX yielded dinuclear complexes [{Cu2(μ-X)2}{Fe(C5H4P(C6H4CH2NMe2-o)2)2}] (2, X = Cl; 3, X = Br; 4 X = I). The reaction of 4 with pyridine affords a binuclear complex, [{Cu2I2(py)2}{Fe(C5H4P(C6H4CH2NMe2-o)2)2}] (5) (py = pyridine) in which each copper atom is tetracoordinated. Similarly, treatment of 4 with 2,2'-bipyridine in 1:1 molar ratio afforded the binuclear complex, [{Cu2I2(2,2′-bipy)}{Fe-(C5H4P(C6H4CH2NMe2-o)2)2}] (6). The equimolar reaction of 3 and 4,4'-bipyridine affords [{Cu2Br2(4,4′-bipy)}2{Fe(C5H4P- (C6H4CH2NMe2-o)2)2}2] (7) in good yield. The complexes 2 and 4 have been structurally characterized; both crystallize in the monoclinic space group with C2/c. In the crystal packing of 2 and 4, the invention-related intermolecular C-H×××X (X = Cl and I) and C-H×××p(ring) interactions are primarily responsible for the crystal packing. A Hirshfeld surface analysis indicates that the most significant contributions to the crystal packing of 2 are from H×××H (81.7%), C×××H/H×××C (12.4%), Cl×××H/H×××Cl (4.3%) contacts, while those for 4 are from H×××H (80.9%), C×××H/H×××C (12.1%), I×××H/H×××I (5.4%) contacts.