title: Dirhenium paddlewheel compounds supported by N,N'-dialkylbenzamidinates: synthesis, structures, and photophysical properties.
abstract: Dirhenium(III,III) compounds Re2(DMBA)4Cl2 (1, DMBA=N,N'-dimethylbenzamidinate) and Re2(DEBA)4Cl2 (2, DEBA=N,N'-diethylbenzamidinate) were synthesized via molten reactions between Re2(OAc)4Cl2 and the corresponding amidine. Re2(DMBA)4(NO3)2 (3) was obtained through reacting Re2(DMBA)4Cl2 with AgNO3. Single crystal X-ray diffraction studies revealed that the Re-Re distances in compounds 1-3 are 2.212(1), 2.217(1), and 2.173(1) A, respectively, which are consistent with the presence of a Re-Re quadruple bond. Voltammetric studies revealed that compound 2 exhibits two quasireversible couples, an oxidation and a reduction, and an irreversible reduction, while compound 1 displays irreversible couples at similar potentials. The three complexes exhibit 1deltadelta* absorption as a shoulder at approximately 440 nm (epsilon approximately 1500 M(-1) cm(-1)). Upon excitation of solid samples or CH2Cl2 solutions of 2 with visible light, emission is observed at 824 nm (77 K) and 833 nm (298 K), respectively. The luminescence is assigned as arising from the 3deltadelta* excited state.
authors.affiliation: Department of Chemistry, University of Miami, Coral Gables, Florida 33124, USA.
authors.forename: Michael Q
authors.initials: MQ
authors.lastname: Dequeant
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Bradley
authors.forename: Guo-Lin
authors.initials: GL
authors.lastname: Xu
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Lutterman
authors.forename: Claudia
authors.initials: C
authors.lastname: Turro
authors.forename: Tong
authors.initials: T
authors.lastname: Ren
mesh_terms: D001549:Benzamides / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010777:Photochemistry; D012211:Rhenium / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D001549:Benzamides; D009942:Organometallic Compounds; D012211:Rhenium