Characterization, spectroscopic properties and crystal structure of a tetraaza[14]annulene manganese(III) complex

The manganese(III) complex of tmtaa, (H(2)tmtaa = 7,16-dihydro-6,8, 15,17-t etramethyldibenzo[b,i][ 1,4,8,11]tetraazacyclotetradecine); was prepared by a ligand exchange reaction and characterized by mass, infrared and electro nic spectra as well as DSC measurement. The crystal structure has been dete rmined by X-ray single crystal diffraction. There are two crystallographica lly independent molecules of Mn(tmtaa)NCS in the asymmetric unit and one in dependent solvent molecule (acetonitrile). The coordination around the mang anese(III) is essentially a five-coordinate square pyramidal configuration with one nitrogen atom of an anionic NCS and four nitrogen atoms of a diani onic tmtaa. The average bond distances of Mn-N for tmtaa are 1.969(6) and 1 .961(3) Angstrom, respectively, while the distances of the manganese to the nitrogen of NCS are 2.094(8) and 2.086(8) Angstrom, respectively. The mang anese(III) is displaced by 0.402 and 0.388 Angstrom, respectively, from the N-4 donor plane.