info:eu-repo/semantics/article
The binuclear dual emitter [Br(CO)3Re(P⋯N)(N⋯P)Re(CO)3Br] (P⋯N): 3-chloro-6-(4-diphenylphosphinyl)butoxypyridazine, a new bridging P,N-bidentate ligand resulting from the ring opening of tetrahydrofuran
Fecha
2017-01Registro en:
Saldías, Marianela; Manzur, Jorge; Palacios, Rodrigo Emiliano; Gomez, María Lorena; de la Fuente, Julio; et al.; The binuclear dual emitter [Br(CO)3Re(P⋯N)(N⋯P)Re(CO)3Br] (P⋯N): 3-chloro-6-(4-diphenylphosphinyl)butoxypyridazine, a new bridging P,N-bidentate ligand resulting from the ring opening of tetrahydrofuran; Royal Society of Chemistry; Dalton Transactions; 46; 5; 1-2017; 1567-1576
1477-9226
CONICET Digital
CONICET
Autor
Saldías, Marianela
Manzur, Jorge
Palacios, Rodrigo Emiliano
Gomez, María Lorena
de la Fuente, Julio
Günther, Germán
Pizarro, Nancy
Vega, Andrés
Resumen
Lithium diphenylphosphide unexpectedly provokes the ring-opening of tetrahydrofuran (THF) and by reaction with 3,6-dichloropyridazine leads to the formation of the ligand 3-chloro-6-(4-diphenylphosphinyl)butoxypyridazine (P⋯N), which was isolated. The reaction of this ligand with the (Re(CO)3(THF)Br)2 dimer yields the novel complex [Br(CO)3Re(μ-3-chloro-6-(4-diphenylphosphinyl)butoxypyridazine)2Re (CO)3Br] (BrRe(P⋯N)(N⋯P)ReBr), which was crystallized in the form of a chloroform solvate, (C46H40Br2Cl2N4O8P2Re2)·(CHCl3). The monoclinic crystal (P21/n) displays a bimetallic cage structure with a symmetry inversion centre in the middle of the rhenium to rhenium line. The molecule shows two oxidation signals occurring at +1.50 V and +1.76 V which were assigned to the ReI /ReII and ReII/ReIII metalcentered couples, respectively, while signals observed at −1.38 V and −1.68 V were assigned to ligand centered reductions. Experimental and DFT/TDDFT results indicate that the UV-Vis absorption maximum of BrRe(P⋯N)(N⋯P)ReBr occurring near 380 nm displays a metal to ligand charge transfer (MLCT) character, which is consistent with CV results. Upon excitation at this wavelength, a weak emission (Φem < 1 × 10−3 ) is observed around 580 nm (in dichloromethane) which decays with two distinct lifetimes τ1 and τ2 of 24 and 4.7 ns, respectively. The prevalence of non-radiative deactivation pathways is consistent with efficient internal conversion induced by the high conformational flexibility of the P⋯N ligand’s long carbon chain. Measurements in a frozen solvent at 77 K, where vibrational deactivation is hindered, show intense emission associated with the 3 MLCT state. These results demonstrate that BrRe(P⋯N)(N⋯P)ReBr preserves the dual emitting nature previously reported for the mononuclear complex RePNBr, with emission associated with π* phenyl and π* pyridazine states.