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 σ-aryl ruthenium( III ) complexes [Ru(L ~(1–4) )(PPh _(3) ) _(2) Cl] ( 1–4 ) (where L ~(1) H _(2) = N -(quinolin-8-yl)benzamide for 1 , L ~(2) H _(2) = 4-chloro- N -(quinolin-8-yl)benzamide for 2 , L ~(3) H _(2) = 4-nitro- N -(quinolin-8-yl)benzamide for 3 , L ~(4) H _(2) = 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(NO _(2) L ~(1–4) )(PPh _(3) ) _(2) (NO)](ClO _(4) ) ( 1a–4a ) (where NO _(2) L ~(1) H _(2) = N -(5-nitroquinolin-8-yl)benzamide for 1a , NO _(2) L ~(2) H _(2) = 4-chloro- N -(5-nitroquinolin-8-yl)benzamide for 2a , NO _(2) L ~(3) H _(2) = 4-nitro- N -(5-nitroquinolin-8-yl)benzamide for 3a , NO _(2) L ~(4) H _(2) = 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 ortho metallation was scrutinized. The coordinated NO molecule was found to be photolabile under visible and UV light.