Synthesis of rhenacyclopentadienes and eta(2):eta(2)-diyne complexes from a labile dirhenium carbonyl and pi-conjugated 1,7-octadiynes: Structural and photophysical characterization

Author(s)

Cardozo, Claudia ^[1] ; Mendoza, Axel ^[1] ; Farias, Gabriela ^[1] ; Barboza Formiga, Andre Luiz ^[2] ; Pena, Deisy ^[1] ; Fuentes, Franmerly ^[1] ; Arce, Alejandro ^[1] ; Otero, Yomaira ^[1]

Affiliation

^[1] Inst Venezolano Invest Cient, Ctr Quim, Apartado 21827, Caracas 1020A - Venezuela

^[2] Univ Estadual Campinas, Inst Chem, POB 6154, BR-13083970 Campinas, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF ORGANOMETALLIC CHEMISTRY; v. 881, p. 34-44, FEB 15 2019.
• Web of Science Citations: 0

Abstract

A series of dirhenium carbonyl compounds containing pi-conjugated diyne ligands and symmetrical 2,5-bis(aryl)rhenacyclopentadienes has been synthesized by reaction of {[}Re-2(CO)(8)(CH3CN)(2)] and 1,8bis(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 {[}Re-2(CO)(7)(mu-eta(1):eta(1):eta(2):eta(2)-C16H14S2)] (1a), {[}Re-2(CO)(6)(CH3CN)(mu-eta(1):eta(1):eta(2):eta(2)-C16H14S2)] (2a) and {[}Re-2(CO)(6)(CH3CN)(mu-eta(1):eta(1):eta(2):eta(2)-C26H20N2)] (2c) are described. DFT calculations were used to evaluate the proposed geometries for the two eta(2):eta(2)-diyne complexes {[}Re-2(CO)(6)(CH3CN)(2)(mu-eta(2):eta(2)-C18H16N2)] (3b), {[}Re-2(CO)(6)(CH3CN)(2)(eta(2):eta(2)-C26H20N2)] (4c), and the rhenacyclopentadiene {[}Re-2(CO)(6)(CH3CN)(mu-eta(1):eta(1):eta(2):eta(C36H26)-C-2)] (2d). The photophysical properties of all complexes were assessed, in that they exhibited fluorescence between 408 and 599 nm with quantum yields of Phi(f) = 0.02-0.09. An exceptional fluorescence quantum yield of Phi(f) = 0.64 was found for {[}Re-2(CO)(6)(CH3CN)(2)(eta(2):eta(2)-C26H20N2)] (4c), which has been attributed to its rigid chelate structure. This work represents the second example of fluorescent 2,5-bis(aryl)rhenaclyclopendadienes reported up to date. (c) 2018 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 14/50906-9 - INCT 2014: in Functional Complex Materials
• Grantee: Fernando Galembeck
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/22127-2 - Development of novel materials strategic for integrated analytical devices
• Grantee: Lauro Tatsuo Kubota
• Support Opportunities: Research Projects - Thematic Grants