SYNTHESIS AND CRYSTAL-STRUCTURE OF THE CO MPLEX MN(III)(BZACEN)(NCS)

The complex [N,N'-ethylenebis(1-phenyl-3-imino-1-butanonato] Mn(III). thiocyanate has been synthesized. The title compound Mn(III)(bzacen)(N CS) crystallizes in the triclinic system,space group <(P)over bar 1>, with parameters: a = 1.0702(3) nm, b = 1.2343(2) nm, c = 0.8999(2) nm, alpha = 93.74(2)degrees, beta = 97.09(2)degrees, gamma = 109.07(2)deg rees, V = 1.1078(9) nm(3), D-c = 1.377 g . cm(-3), Z = 2, F (000) = 47 6, mu = 6.85 cm(-1). The final R value is 0.052 for 3205 observed refl ections with I greater than or equal to 4 sigma(I). The coordination g eometry around Mn atom is distorted square pyramidal,the basal plane c onsisting oi two nitrogen atoms and two oxygen atoms from the Schiff b ase ligand bzacen(2-), while axial site is occupied by a nitrogen atom from NCS- group. The packing of the molecules leaves empty channels r unning through the crystal along the c axis. The shifts of nu(C=N,)nu( C=O) and nu(C=C) to lower frequencies in IR and Raman spectra indicate that the ligand bzacen(2-) has been coordinated to Mn atom through it s nitrogen and oxygen atoms. The lines observed at 462 cm(-1) and 399 cm(-1) in Raman spectrum are assigned to Mn-O and Mn-N vibrations, res pectively. There are pi similar to pi transition, d similar to pi* ch arge-transfer transitions and d similar to d transition in electronic spectrum. The current potential curve in acetontrile reveals that Mn (III) is in stable valence state. The electronic structure was studied by the EHMO calculation.