Tetracoordinated Manganese(III) Alkylcorrolates. Spectroscopic Studies and the Crystal and Molecular Structure of (7,13-Dimethyl-2,3,8,12,17,18-hexaethylcorrolato)manganese(III).

(2,3,7,8,12,13,17,18-Octamethylcorrolato)manganese(III), [Mn(OMC)], has been characterized by several physical measurements. In the presence of nitrogenous bases the complex exists as a valence tautomer [Mn(II)(OMC(*+))] as demonstrated by (1)H NMR and EPR. Complete resonance assignment in the NMR spectrum has been achieved by systematic substitution of the peripheral substituents. The crystal structure of the first example of a tetracoordinated tetrapyrrolic macrocycle Mn(III) complex, (7,13-dimethyl-2,3,8,12,17,18-hexamethylcorrolato)manganese(III), [Mn-7,13-Me(2)-HEC)], is also reported. Crystal data with Cu Kalpha (lambda = 1.541 78 Å) at 293 K are as follows: C(33)H(39)MnN(4), a = 4.671(2) Å, b = 28.31(2) Å, c = 20.882(6) Å, beta = 94.60(3) degrees, V = 2753(2) Å(3), Z = 4, monoclinic, space group P2(1)/n, 4088 data, R1 = 0.0563 for 4088 observed reflections with I > 2sigma(I). The analysis reveals a high degree of planarity of the macrocycle and the existence of strong overlap between the pi systems with the formation of an infinite stack of molecules.