Unusual bond lengths, conformations, and ligand exchange rates in B12 models with the bis(salicylidene)-o-phenylenediamine equatorial ligand

Abstract

J. Am. Chem. Soc.sequence, the energy for ionization of the iron ion in these complexes is dramatically lowered, thus rendering more accessible the iron(1V) oxidation state. The d-orbital energy levels must be directly related to the inductive effect of the axial u-bonded group. This assumption is strengthened by the fact that half-wave potentials of +0.25 and +0.39 V are observed for (OEP)Fe(n-C4Hg) and (C I ,TPP) Fe(n-C4Hg), re~pectively,~~ compared to potentials of +0.48 V for oxidation of (OEP)Fe(C6Hs) and +0.61 V for oxidation of (TPP)Fe (C,H,).The half-wave potential of the second oxidation appears to be insensitive to the nature of the axial ligand. This electron transfer takes place at E,, = +1.43 V in CH2C12 or El,? = +1.52 V in DME, 0.1 M TBA(PF,), for (TPP)Fe(C6HS) while the oxidation half-wave potential for (TPP)FeX occurs at Ellz = +1.40 V in CH2CI2, 0.1 M TBA(C104) (where X stands for an anionic halide or p~eudohalide).~~ These observations suggest that the first oxidation of (P)Fe(C&) effectively occurs at the metal center.The electronic absorption spectra of the one-electron oxidized species obtained are in agreement with the above statement. For

Crystal structure of (E)-1-(2-chlorophenyl)-N-(4-chlorophenyl)methanimine, C13H9Cl2N

“…Schi -bases have been of great interest for many years because of their wide application in metal coordination chemistry as important classes of ligands and higher bioactivity [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. In order to search for new Schi -bases, the title compound was synthesized and its crystal structure determined.…”

Crystal structure of 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4- methylphenol, C14H14N2O

“…[7], models of reaction centersofmetalloenzymes [8],and nonlinearoptical materials [9].Here we designed and synthesized anew Schiff base named2 -((E)-(6-methylpyridin-2-ylimino)methyl)-4-methylphenol. Thecrystal structure of the title compound is only built up by the C 14 H 14 N 2 Omolecules, in which all bond lengths are in normalr anges.…”

Crystal structure of 3,3′-[2,2′-(1,2-ethylenedioxy)dibenzylmethylimino] bis(acetophenone oxime), C32H30N4O4

“…Oxime-type chelating compounds and their derivatives have drawn much attention in the last few decades because these compounds cana ccommodate one, two or more metal centers and form homo-and heteronuclearmetal complexes with interesting properties [1][2][3][4], such as excellent catalytic activity for epoxidation and aziridination [5].Inaddition, they arealso used as models for reaction centers in metalloenzymes [6],non-linear optical materials [7],a nd molecular recognition and biological activity [8]. …”