Synthesis, Properties, and Crystal Structures of a Series of Dinuclear Manganese(III) Complexes with 1,5-Bis(salicylideneamino)-3-pentanol and Various Anions: Formation of a Tetranuclear Manganese(III) Complex

Abstract

μ-Alkoxo-bridged dinuclear and tetranuclear manganese(III) complexes with 1,5-bis(salicylideneamino)-3-pentanol (H3L), [Mn2(L)(CH3O)Cl2(CH3OH)2] (1), [Mn2(L)(CH3O)(CH3COO)(CH3OH)2]X (X = Br (2), I (3)), [Mn2(L)(CH3O)(CH3COO)(CH3OH)Y] (Y = NCS (4), N3 (5), ClO4 (6)), [Mn2(L)(CH3O)(NCO)2(H2O)2] (7), and [Mn4(L)2(O)2(CH3COO)2]·4H2O·2CH3OH (8) have been prepared and characterized by infrared and electronic spectra, magnetic susceptibilities, and cyclic voltammetry. The molecular structures of 1–5, 7, and 8 were determined by the single-crystal X-ray structure analyses. All the complexes except for 8 have a similar structure, where Cl−, CH3COO−, N3−, NCS−, CH3OH, or H2O is incorporated into the fifth or sixth coordination site on the Mn2(L)(CH3O) plane. The structure of 8, is a tetramer consisting of two Mn2(L)(O)(CH3COO) dimeric units held together through the oxo ions and the phenoxo-oxygen atoms of L. The spectral and magnetic properties were discussed in relation to the crystal structures.

New dimanganese(III) complexes of pentadentate (N2O3) Schiff base ligands with the [Mn2(μ-OAc)(μ-OR)2]3+ core: Synthesis, characterization and mechanistic studies of H2O2 disproportionation

“…3) was obtained with the following parameters: J = À13.1 cm À1 , g = 1.90 and p = 0.2%. The calculated exchange parameter J falls in the range observed for other dialkoxo bridged diMn III complexes with short MnÁ Á ÁMn distances (2.98-3.00 Å ) [18,19,27,[34][35][36][37] that allow direct overlap between the d xy orbitals.…”

A new, dinuclear high spin manganese(III) complex with bridging phenoxy and methoxy groups. Structure and magnetic properties

“…The presence of two non-parallel Jahn-Teller axes is a very unusual structural feature for dinuclear Mn III complexes where a parallel orientation has been observed for a number of complexes related to 2 [27][28][29]. However, a similar type of Jahn-Teller axes orientation was reported for the tetranuclear complex [Mn 4 (L(O) 2 OAc) 2 ] AE 4H 2 O AE MeOH (where LH 2 = 1,5-bis(salisylideneamino)-3-pentanol) [30]. Calculating the least squares planes for the equatorial O 3 N donor set on respective metal atom shows that the equatorial coordination around Mn1 is more distorted than that around Mn2.…”

Tetranuclear manganese (III) salicylaldoxime ensemble

“…The elucidation of the crystal structures of oxygen-evolving photosystem II from Thermosynechococcus elongatus at 3.8 Å resolution by Zouni et al [5] and Thermosynechococcus vulcanus at 3.7 Å resolution by Kamiya and Shen [6], respectively, indicated that a tetranuclear manganese center is at the heart of the water splitting reaction, triggered efforts toward the synthesis of structural and functional analogues of the oxygen-evolving complex. The three general classes of tetranuclear manganese complexes with variable oxidation states which are synthesized are (i) the [Mn 4 (l 3 -O) 2 ] core using the carboxylate aggregate developed by Christou and Hendrickson [7][8][9] (ii) the [Mn 4 (L) 2 (O) 2 (CH 3 COO) 2 ] core where L = the schiff base ligands 2,6-bis(salicylideneaminomethyl)-4-methylphenol or 1,5-bis-(salicylideneamino)-3-pentanol or 2,6-bis(N-(4-imidazolylethyl)iminomethyl]-4-methylphenol reported by Mikuriya et al [10][11][12][13] and (iii) the inorganic analogues of M 2+ (12-crown-4) such as Mn(II)[Mn(III)-salicylhydroximate] 4 described by Pecoraro et al [14,15] In all the above cases the Mn 4 (III) aggregate is formed with the participation of ancillary bridging ligands such as acetato-, benzoato-, etc. Herein we report the X-ray structure of a neutral tetranuclear Mn(III) cluster containing The article was accepted and intended for the Special issue but was left out due to a production error.…”