The absorption and fluorescence spectra at different excitation wavelengths of the recently reported rhenium carbonyl complexes [Re2(µ:3-C12H10N2)(CO)8 (1), [Re2(µ-H)(µ:3-C12H9N2)(CO)7 (2) and [Re2(µ-H)(µ:5-C12H9N2)(CO)6 (3) have been studied and compared between them with the aim to evaluate their potential as molecular switches and charge transfer species. Their photostability in dichloromethane solutions (aerobic conditions) under UV-A and UV-B light irradiation, and photoinduced charge transfer reactions with tetrazolium blue were analyzed. The redox properties of complexes 1-3 have been examined by cyclic voltammetry: the behavior of complexes 1 and 3 is very similar, giving quasi-reversible oxidation-reduction processes, while for 2 a totally irreversible oxidation-reduction process was observed.

A new tetranuclear rhenium derivative [Re2(CO)8(C14H10N4)Re2(CO)8] was obtained from the reaction of [Re2(CO)8(CH3CN)2] and 2,3-bis(2-pyridyl)pyrazine. The ligand behaves as an 8e-donor bridge between two Re(CO)3 moieties through two σ,σ′-N,N′ interactions.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Treatment of trans-1,2-bis(2-pyridyl)ethene (C12H10N2) with the labile cluster [Os-3(CO)(10)(CH3CN)(2)] in refluxing THF generated the products: [Os-2(mu:eta(4)-C12H10N2)(CO)(6)] (1) and [Os-3(mu:eta(4)-C12H10N2)(CO)(10)] (2). When the reaction is carried out in refluxing acetonitrile the products [Os-3(mu-H)(2)(mu(3):eta(3)-C12H10N2)(CO)(8)] (3), [Os-3(mu-H)(mu(3):eta(4)-C12H9N2)(CO)(8)] (4) and {Os-3(mu-CO)(mu(3):eta(3)-C12H10N2)(CO)(8)} (5) are obtained in addition to compounds 1 and 2. The X-ray structures for 1, 3 and 4 are reported. We have established that both pyridine nitrogen atoms are co-ordinated in all five complexes. I and 2 contain the ligand incorporated in a doubly-bridging manner, and for clusters 3, 4 and 5 hydrogen atom transfer at the central ethene group has lead to bridging alkylidene and vinyl systems within triply-bridging ligands. (C) 2004 Elsevier B.V. All rights reserved.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The reaction of the labile compound [Re-2(CO)(8)(CH3CN)(2)] with trans-1,2-bis(2-pyridyl)ethene (C12H10N2) at room temperature in tetrahydrofuran affords the compounds [Re-2(mu:eta(3)-C12H10N2)(CO)(8)] (1) and the oxidative addition product [Re-2(mu-H)(mu:eta(3)- C12H9N2)(CO)(7)] (2). When the reaction is carried out at temperatures of refluxing tetrahydrofuran, besides compounds 1 and 2, the oxidative addition product [Re-2(mu-H)(mu:eta(4)-C12H9N2)(CO)(6)] (3), the insertion product [Re-2(mu:eta(4)-C12H10N2)(CO)(8)] (4) and [Re-2(mu:eta(6)-C14H18N4)(CO)(6)] (5) are obtained. Compound 5 contains the organic ligand rtct-tetrakis(2-pyridyl)cyclobutandiyl which is derived from a [2 + 2] cycloaddition of 1,2-bis(2-pyridyl)ethene mediated by its coordination to the bimetallic framework. The molecular structures of 1, 2, 4 and 5 were confirmed by X-ray crystallographic studies. (C) 2004 Elsevier B.V. All rights reserved.