Formation, crystal structure and coordination chemistry of Mn(III)(eospz)(SH) [oespz(2-)] =2,3,7,8,12,13,17,28-octakis(ethylsupfanyl)-5,10,15,20-tetraazaporphyrinate dianion] complexe

Reaction of [Mn(oespz)] [oespz(2-) = 2,3,7,8,12,13,17, 18-octakis(ethylsulfanyl)-5, IO, 15,20-tetraazaporphyrinate dianion (porphyrazinate)] with CS, and, subsequently, with THF, afforded the hydrogensulfido(1 -)manganese(Iu) ethylsulfanylporphyrazinate [ln(oespz)(SK)], in high yield. The S-H stretching absorptions are not observed in the IR spectrum of the complex, whereas a peak at delta 10.3 (vs. SiMe4) ascribed to the hydrogensulfido proton resonance, is observed in the H-1 NMR spectrum. The complex was shown to be isostructural with [M(oespz)Cl] (M = Fe or Mn) by X-ray crystallography. The crystal packing of the complex consists of slipped stacks of dimeric units with the monomers positioned in a trans fashion with respect to the Mn-S-apical bond. Magnetic data are consistent with weakly antiferromagnetically coupled high spin (S = 2) manganese(III) centers. A possible pathway to the oxidative addition of CS, to the manganese(II) center has been proposed. In CHCl3 [Mn(oespz)(SH)] reacts reversibly through the axial hydrosulfido ligand with the sterically hindered base 2,4,6-trimethylpyridine, whereas the complex co-ordinates 1-methylimidazole reversibly on the vacant site of manganese. Treatment of the complex with 1-methylimidazole in benzene leads to a Mn-III-Mn-II redox process, as deduced from the UV/VIS spectra.