Synthesis of rhenacyclopentadienes and η2:η2-diyne complexes from a labile dirhenium carbonyl and π-conjugated 1,7-octadiynes: Structural and photophysical characterization

Publication date: Available online 4 December 2018Source: Journal of Organometallic ChemistryAuthor(s): Claudia Cardozo, Axel Mendoza, Gabriela Farías, André Luiz Barboza Formiga, Deisy Peña, Franmerly Fuentes, Alejandro Arce, Yomaira OteroAbstractA series of dirhenium carbonyl compounds containing π-conjugated diyne ligands and symmetrical 2,5-bis(aryl)rhenacyclopentadienes has been synthesized by reaction of [Re2(CO)8(CH3CN)2] and 1,8-bis(aryl)-1,7-octadiyne derivatives [aryl = 2-thienyl (a), 2-pyridyl (b), 2-quinolyl (c) and 9-phenanthrenyl (d)]. We found that diyne ligands undergo coordination to the labile rhenium dinuclear in bridging or chelate modes, however, the formation of metallacyclopentadiene complexes was favorably observed. All products were fully characterized by IR, NMR, ESI-MS, UV–Vis and fluorescence spectroscopy. Single-crystal structures of three new 2,5-bis(aryl)rhenacyclopentadienes [Re2(CO)7(μ-η1:η1:η2:η2-C16H14S2)] (1a), [Re2(CO)6(CH3CN)(μ-η1:η1:η2:η2-C16H14S2)] (2a) and [Re2(CO)6(CH3CN)(μ-η1:η1:η2:η2-C26H20N2)] (2c) are described. DFT calculations were used to evaluate the proposed geometries for the two η2:η2-diyne complexes [Re2(CO)6(CH3CN)2(μ-η2:η2-C18H16N2)] (3b), [Re2(CO)6(CH3CN)2(η2:η2-C26H20N2)] (4c), and the rhenacyclopentadiene [Re2(CO)6(CH3CN)(μ-η1:η1:η2:η2-C36H26)] (2d). The photophysical properties of all complexes were assessed, in that they exhibited fluorescence between 408 and 599 nm with quantu...

Source: Journal of Organometallic Chemistry - December 5, 2018 Category: Chemistry Source Type: research