title: Ruthenium porphyrins with axial π-conjugated arylamide and arylimide ligands.
abstract: A series of ruthenium porphyrins [Ru(IV)(por)(NHY)2] and [Ru(VI)(por)(NY)2] bearing axially coordinated π-conjugated arylamide and arylimide ligands, respectively, have been synthesized. The crystal structures of [Ru(IV)(tmp)(NHY)2] (tmp = 5,10,15,20-tetramesitylporphyrinato(2-)) with Y = 4'-methoxy-biphenyl-4-yl (Ar-Ar-p-OMe), 4'-chloro-biphenyl-4-yl (Ar-Ar-p-Cl), and 9,9-dibutyl-fluoren-2-yl (Ar^Ar) show axial Ru-N(arylamide) distances of 1.978(4), 1.971(6), and 1.985(13) Å, respectively. [Ru(IV)(tmp)(NH{Ar^Ar})2] is an example of metalloporphyrins that bind an arylamide ligand featuring a co-planar biphenyl unit. The [Ru(IV)(por)(NHY)2] complexes show a quasi-reversible reduction couple or irreversible reduction wave attributed to Ru(IV)→Ru(III) with Epc from -1.06 to -1.40 V versus Cp2Fe(+/0) and an irreversible oxidation wave with Epa from -0.04 to 0.19 V versus Cp2Fe(+/0). Reaction of the [Ru(IV)(por)(NHY)2] with bromine afforded [Ru(IV)(por)(NHY)Br]. PhI(OAc)2 oxidation of the [Ru(IV)(por)(NHY)2] gave [Ru(VI)(por)(NY)2]; the latter can be prepared from reaction of [Ru(II)(por)(CO)] with aryl azides N3Y. The crystal structure of [Ru(VI)(tmp)(N{Ar-Ar-p-OMe})2] features Ru-N(arylimide) distances of 1.824(5) and 1.829(5) Å. Alkene aziridination and C-H amination catalyzed by "[Ru(II)(tmp)(CO)]+π-conjugated aryl azides", or mediated by [Ru(VI)(por)(NY)2] with Y = biphenyl-4-yl (Ar-Ar) and Ar-Ar-p-Cl, gave aziridines and amines in moderate yields. The electronic structure of [Ru(VI)(por)(NY)2] was examined by DFT calculations.
authors: Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong (P. R. China).
authors: Siu-Man
authors: SM
authors: Law
authors: Daqing
authors: D
authors: Chen
authors: Sharon Lai-Fung
authors: SL
authors: Chan
authors: Xiangguo
authors: X
authors: Guan
authors: Wai-Man
authors: WM
authors: Tsui
authors: Jie-Sheng
authors: JS
authors: Huang
authors: Nianyong
authors: N
authors: Zhu
authors: Chi-Ming
authors: CM
authors: Che
keywords: N ligands; metal-amide complexes; metal-imide complexes; porphyrinoids; ruthenium