SYNTHESES, ELECTROCHEMISTRY, AND SPECTROSCOPIC AND MAGNETIC-PROPERTIES OF NEW MONONUCLEAR AND BINUCLEAR COMPLEXES OF VANADIUM(III), VANADIUM(IV), AND VANADIUM(V) CONTAINING THE TRIDENTATE MACROCYCLE 1,4,7-TRIMETHYL-1,4,7-TRIAZACYCLONONANE (L) - CRYSTAL-STRUCTURES OF [L2V2(ACAC)2(MU-O)]I2.2H2O, [L2V2O4(MU-O)].14H2O, AND [L2V2O2(OH)2(MU-O)](CLO4)2

The reaction of LVCl3-dmf (1), where L represents the tridentate ligand l,4,7-trimethyl-l,4,7-triazacyclononane (C9H21N3) and dmf is dimethylformamide, with CF3SO3H yields the very reactive green complex LV(O3SCF3)3(2), which is a useful starting material for the synthesis of a variety of mononuclear and binuclear complexes of vanadium. Thus, 2 reacts under anaerobic conditions with NaSCN affording LV(NCS)3(3) and with NaN3in the presence of air affording LVO(N3)2(4). Hydrolysis of 2 under anaerobic conditions in the presence of NaOCN yields the oxo-bridged, purple binuclear species [L2V2(OCN)4(µ-O)]·2H2O (6) whereas in the presence of O2the reaction yields LVO(NCO)2(5). Hydrolysis of 1 with acetylacetonate (acac) affords upon addition of Nal purple crystals of [L2V2(acac)2(ε-O)]I2-2H2O (7), the structure of which has been determined by X-ray crystallography: space group P21a = 9.078 (6), b = 12.785 (8), c = 16.96 (1) Ϗ; β = 99.93 (5)°; Z = 2. The same reaction carried out in the presence of sodium benzoate affords green crystals of [L2V2(µ-O)(µ-O2CPh)2]I2·H2O (8). Two binuclear complexes of vanadium(V) have also been synthesized: [L2V2O5]-14H2O (9) is synthesized from NH4VO3(or V2O5) and the ligand L in a CH3CN/H2O mixture. 9 is readily protonated in acidic media, yielding yellow crystals of [L2V2O2(OH)2(µ-O)](C1O4)2(10). The crystal structures of 9 and 10 have been determined by X-ray crystallography. Crystal data for 9: space group P21c; a = 10.587 (3), b = 8.608 (2), c = 23.049 (4) Å; β = 115.74 (2)°; Z = 2. Crystal data for 10: space group P21/n; a = 8.762 (3), b = 13.975 (5), c = 11.988 (3) Å; β = 101.23 (3)°; Z = 2. Spectral (UV-vis) and magnetic properties of new complexes are described; the electrochemistry has also been investigated. © 1990, American Chemical Society. All rights reserved.