[1,10]-Phenanthrolin-2-yl Ketones and Their Coordination Chemistry

Abstract

A synthetic protocol involving the Friedländer reaction of 8-amino-7-quinolinecarbaldehyde followed by potassium dichromate oxidation was applied to 2,3,4-pentanetrione-3-oxime and 1-(pyrid-2'-yl)propane-1,2-dione-1-oxime to provide the ligands di-(phenathrolin-2-yl)-methanone (1) and phenanthrolin-2-yl-pyrid-2-yl-methanone (8), respectively. Ligand 1 complexed as a planar tetradentate with Pd(II) to form [Pd(1)](BF4)2 and with Ru(II) and two 4-substituted pyridines (4-R-py) to form [Ru(1)(4-R-py)2](PF6)2 where R = CF3, CH3, and Me2N. With [Ru(bpy)2Cl2], the dinuclear complex [(bpy)2Ru(1)Ru(bpy)2](PF6)4 was formed (bpy = 2,2'-bipyridine). Ligand 8 afforded the homoleptic Ru(II) complex [Ru(8)2](PF6)2, as well as the heteroleptic complex [Ru(8)(tpy)](PF6)2 (tpy = 2,2';6,2''-terpyridine). The ligands and complexes were characterized by their NMR and IR spectra, as well as an X-ray structure determination of [Ru(1)(4-CH3-py)2](PF6)2. Electrochemical analysis indicated metal-based oxidation and ligand-based reduction that was consistent with results from electronic absorption spectra. The complexes [Ru(1)(4-R-py)2](PF6)2 were sensitive to the 4-substituent on the axial pyridine: electron donor groups facilitated the oxidation while electron-withdrawing groups impeded it.

Iron Complexes of Square Planar Tetradentate Polypyridyl-Type Ligands as Catalysts for Water Oxidation

“…In surveying the literature, we find only a very few systems with a similar geometry. These are mainly bis-phenanthrolines linked at their 2-position with either a carbonyl group 15 or a tertiary amine. Following a reported procedure, we prepared the known diphen amine (dpa) 16 in order to compare its metal binding properties to ppq.…”

Synthesis and spectroscopic and electrochemical properties of new ligand 1,3-bis(4′-methyl-2,2′-bipyridin-4-yl)propan-2-one and its ruthenium(II) complexes

“…When introduced the Ru(II) units to L, the bipyridyl ring stretching shifted from the low frequency (1595 cm À1 ) to higher ones (1619 cm À1 ) as the result of the increasing of the coordinated bipyridyl units. As reported, the substituent group joined to the carbonyl group could distort the sp 2 nature of the carbonyl group, leading a lower C-O bond order [8]. However, all of the carbonyl group stretching bands of the Ru(II) L complexes locates at 1722 cm À1 , indicating that the Ru(II) moieties does not affect the character of the carbonyl group of L. Herein, there is small interaction between the Ru(II) moieties and the carbonyl group of the bridging ligand.…”

New Series of Ruthenium(II) and Osmium(II) Complexes Showing Solid-State Phosphorescence in Far-Visible and Near-Infrared

“…All calculations were carried out using Gaussian 03. 23 Electronic configurations of 3 MLCT and 3 MC dd states were calculated following the literature methodology. 16,24 The 3 MLCT state geometry was obtained by geometry optimization along the triplet-state potential energy surface (PES) using the X-ray crystal structure as the initial geometry.…”