Site-specific orthometallation via C-H bond activation and syntheses of ruthenium(III) organometallics: studies on nitric oxide (NO) reactivity and photorelease of coordinated NO

摘要

A new family of sigma-aryl ruthenium(III) complexes [Ru(L1-4)(PPh3)(2)Cl] (1-4) (where (LH2)-H-1 = N-(quinolin-8-yl) benzamide for 1, (LH2)-H-2 = 4-chloro-N-(quinolin-8-yl) benzamide for 2, (LH2)-H-3 = 4-nitro-N-(quinolin-8-yl) benzamide for 3, (LH2)-H-4 = 3-nitro-N-(quinolin-8-yl) benzamide for 4 and H = dissociable protons) derived from bidentate ligands having amide bonds was synthesized through C-H bond activation. These organometallic ruthenium(III) complexes were treated with nitric oxide (NO) to afford the nitrosyl complexes [Ru(NO2L1 4)(PPh3)(2)(NO)](ClO4) (1a-4a) (where (NO2LH2)-H-1 = N-(5-nitroquinolin-8-yl) benzamide for 1a, (NO2LH2)-H-2 = 4-chloro-N-(5-nitroquinolin-8-yl) benzamide for 2a, (NO2LH2)-H-3 = 4-nitro-N-(5-nitroquinolin-8-yl) benzamide for 3a, (NO2LH2)-H-4 = 3-nitro-N-(5-nitroquinolin-8-yl) benzamide for 4a and H = dissociable protons). All ruthenium complexes were characterized by various spectroscopic techniques. An X-ray crystallographic study afforded the molecular structure of complex 4a and the site-specific orthometallation was scrutinized. The coordinated NO molecule was found to be photolabile under visible and UV light.