Iron(II)-diimine complexes: solvatochromism and reactivity

Abstract

Reactivity trends are reported for aquation of tris(5-nitro-1,10-phenanthroline)iron(II) in ternary H20-t-BuOHpolyethyleneglycol (PEG400) solvent media. Wavelengths of maximum absorption for the lowest energy chargetransfer band of dicyanobis(2-acetylpyridineoximato)iron(II) are reported for the same series of ternary solvent mixtures. There is no overall correlation of rate constants with wavelength shifts, indicating that solvation effects in the two systems are not directly related.

Derivatives of Bis(2,2′-bipyridyl)dicyanoiron(II) with Long Alkyl Chains − Versatile Solvatochromic Probes that Form Metalloaggregates in Water-Rich Media

“…The plots of ν max (MLCT) for similar inorganic complexes versus the solvent E T values found in the literature typically exhibit two correlation lines, which correspond to hydroxylic and non-hydroxylic solvents. [1,17,18] Such plots for complexes 1Ϫ4 exhibit roughly the same behaviour, but with a novel feature: a third correlation line is observed for nonpolar solvents. This feature is absent from the plots reported in the literature, since the complexes were not soluble in nonpolar solvents.…”

Kinetic, solvation and reactivity studies of iron(II) complexes of monoxime and dioxime ligands

“…The results are reported in Tables 1-3 [10,14]. Acid dissociation of iron(II)-monoxime complexes could be due to iron-nitrogen bond breaking and protonation of the nitrogen atom of the pyridine ring [15] as shown in Scheme 1.…”

Solvatochromism and solvation of transition metal complexes in ternary aqueous solvent media

“…The connection between indications of preferential solvation from solvatochromism and from transfer chemical potentials has been discussed elsewhere [49]. Marked preferential solvation by water has also been deduced from the solvatochromic behaviour of Fe(CN) 2 (acpyox) 2 , where acpyox = 2-acetylpyridineketoximate (C 5 H 4 NÁC(Me)=NO -), in the water-t-BuOH-PEG system [47]. Figure 5 suggests a considerably smaller degree of preferential hydration for [MoO(CN) 3 (phen)] -in the water-1-hexanol-PEG solvent system.…”

“…Water-n-hexane-i-PrOH [45] Mo(CO) 4 (phen) Mo(CO) 4 (fz) 2-Water-n-hexane-i-PrOH b [38] Fe(CN) 5 (Xpy) mWater-1-hexanol-CTAB [9] Fe(CN) 2 (bipy) 2 Water-1-hexanol-CTABwater-1-octanol-DME or PEG [46] Fe(CN) 2 (Rsb) 2 Water-1-hexanol-AOT [30] Fe(CN) 2 (Fsb) 2 Water-1-hexanol-DEGDE [28] Fe(CN) 2 (acpyox) 2 Water-t-BuOH-PGE [47] a Ligand abbreviations : phen 1,10-phenanthroline; fz ferrozine; Xpy 4-(t-butyl)pyridine, 4-(1-butylpentyl)pyridine, or 2-methylpyrazinium; bipy 2,2 0 -bipyridyl; Rsb Schiff base from 2-acetyl pyridine and a long-chain amine, 1-Me(CH 2 ) n NH 2 with n = 11, 15, or 17; Fsb Schiff base from 2-acetylpyridine and 3-fluoro-4-methylaniline; acpyox 2-acetylpyridineketoximate b Also n-BuOH/toluene/water/SDS Fig. 1 Wavelengths of maximum absorption, k max /nm, for the charge-transfer band of Fe(CN) 2 (bipy) 2 in DEGDME-tBuOH-water solvent media Fig.…”

“…References to scattered and isolated earlier articles of solvatochromism in threecomponent solvent systems are collected in Table 1 [9,28,30,38,[45][46][47], while a selection of more recent results is presented and discussed below. This selection has been chosen to provide representative illustrations of systems, results and insights-further information, including precise details of solvent compositions and wavelengths or wavenumbers of maximum absorption for the systems illustrated below, and results for a number of related systems, may be obtained from the author for correspondence.…”