RESUMEN
We present the photoreaction of newly prepared bis(6,6'-dimethyl-2,2'-bipyridine)(oxalato)rhodium(III) ([Rh(N^N)2(ox)]+) in CD3OD. Photoirradiation of this complex causes the dissociation of ox, followed by the formation of the unprecedented Rh(III) complex with Rh-H and Rh-C s bonds, [Rh(N^N)(C^N)(H)(CD3OD)]+ (C^N = [6,6'-dimethyl-2,2'-bipyridine]-3-yl-κC3,κN1'). This hydride formation and cyclometallation spontaneously proceed owing to the conflict between the steric hindrance arising from the methyl groups of N^N and the driving force for the structural change due to [Rh(N^N)2]+ formation. Although [Rh(N^N)(C^N)(H)(CD3OD)]+ is initially converted to [Rh(N^N)2]+ by photoirradiation, it is immediately regenerated by the rollover cyclometallation of the [Rh(N^N)2]+ complex. [Rh(N^N)(C^N)(H)(CD3OD)]+ undergoes H/D exchange for the H atoms in the Rh-H bond and at the 3, 3'-positions of the N^N ligand during the photoirradiation. DFT calculations predict with reasonable certainty the spontaneous structural change of [Rh(N^N)2]+ to [Rh(N^N)(C^N)(H)(CD3OD)]+ and the subsequent photodriven Rh-C bond rupture leading to the formation of [Rh(N^N)2]+ accompanied by H/D exchange reactions.
RESUMEN
Here, we report a photodynamic therapy (PDT) photosensitizer of Nâ§Câ§N-coordinated Pt(II) complexes: [Pt(L)(solv)]+ (HL = 1,3-(2-dipyridyl)benzene) and [Pt(L)]+@HSA, which is the Pt(II) complex encapsulated in human serum albumin (HSA). The quantum yield of singlet oxygen production for [Pt(L)(solv)]+ is more than 50%, while that for [Pt(L)]+@HSA is much lower. Photoimages of human umbilical vein endothelial cells (HUVECs) treated with the Pt(II) complexes suggest that [Pt(L)(solv)]+ is delocalized in the entire cell after the fast uptake by diffusion and [Pt(L)]+@HSA is taken up by endocytosis and localized on organelles and the cell membrane. [Pt(L)(solv)]+ shows high photocytotoxicity for HUVECs, while [Pt(L)]+@HSA does not show photocytotoxicity.
Asunto(s)
Células Endoteliales de la Vena Umbilical Humana , Fotoquimioterapia , Fármacos Fotosensibilizantes , Humanos , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/síntesis química , Compuestos Organoplatinos/farmacología , Compuestos Organoplatinos/química , Compuestos Organoplatinos/síntesis química , Supervivencia Celular/efectos de los fármacos , Estructura Molecular , Oxígeno Singlete/metabolismo , Albúmina Sérica Humana/química , Albúmina Sérica Humana/metabolismo , Platino (Metal)/química , Platino (Metal)/farmacología , Tensoactivos/química , Tensoactivos/farmacología , Tensoactivos/síntesis química , Complejos de Coordinación/farmacología , Complejos de Coordinación/química , Complejos de Coordinación/síntesis químicaRESUMEN
A chiral platinum(II) complex with a helical Schiff-base [4]helicene ligand exhibits intense red circularly polarized phosphorescence (CPP) with a glum of 0.010 in the dilute solution state. The intense CPP was caused by a change in the electronic transition character based on the induction of the helical structure.