title: Intramolecular hydrogen bonding stabilizes the nuclearity of complexes. A comparative study based on the H-carborane and Me-carborane framework.
abstract: New dinuclear carboranylcarboxylate-bridged and mononuclear copper(ii) compounds containing the 1-CO2H-2-H-1,2-closo-C2B10H10 carborane ligand () have been synthesized from the previously synthesized dinuclear compound [Cu2(μ-L)4(THF)2], . Reaction of with CuSO4 in THF leads to the dinuclear compound [Cu2(μ-L)4(THF)2], . The reaction of with different terminal pyridyl ligands leads to the formation of a series of structurally analogous complexes by substitution of the terminal ligand THF (Lt = py, ; p-CF3-py, ; p-CH3-py, ), which maintain the structural Cu2(μ-O2CR)4 core in most of the cases except for o-(CH3)2-py where a mononuclear compound () is exclusively obtained. In the case of and , other dinuclear compounds [Cu2(L)4(Lt)4], and are obtained in lower yield. These compounds have been characterized using analytical, spectroscopic (NMR, IR, UV-visible) and electrochemical techniques (CV, DPV). X-ray analysis revealed a paddle-wheel structure for the main dinuclear compounds with a square-pyramidal geometry around each copper ion and the carboranylcarboxylate ions bridging two copper atoms in syn-syn mode. In the case of and there are two carboranylcarboxylate ions bridging the copper atoms in syn-anti mode whereas the other two adopt a monodentate coordination mode. The mononuclear complex obtained with the o-(CH3)-py ligand presents a square-planar structure, in which the carboranylcarboxylate ligand adoptsmonodentate coordination. The effect of the substituent group on the cluster of the carboranylcarboxylate ligands on the reactivity of compound is also discussed.
authors.affiliation: Departament de Química and Serveis Tècnics de Recerca, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Spain. marisa.romero@udg.edu.
authors.forename: Mònica
authors.initials: M
authors.lastname: Fontanet
authors.forename: Montserrat
authors.initials: M
authors.lastname: Rodríguez
authors.forename: Xavier
authors.initials: X
authors.lastname: Fontrodona
authors.forename: Isabel
authors.initials: I
authors.lastname: Romero
authors.forename: Clara
authors.initials: C
authors.lastname: Viñas
authors.forename: Francesc
authors.initials: F
authors.lastname: Teixidor