Cobalt(II) complexes with aromatic carboxylates and N-functionalized cyclam bearing 2-pyridylmethyl pendant arms

Novel binuclear Co(II) complexeswithN-functionalized cyclam N,N?,N",N???-tetrakis( 2-pyridylmethyl)tetraazacyclotetradecane (tpmc) and one of the aromatic monoor dicarboxylato ligands (benzoate, phthalate or isophthalate ions) were prepared. They were analyzed and studied by elemental analyses (C, H, N), electrical conductivities, VIS and IR spectroscopy andmagnetic as well as cyclic voltammetric measurements. In [Co2(C6H5COO)2tpmc]ClO4)2.3H2O, the benzoate ligands are most probably coordinated as chelates in the trans-position to each Co(II) and the macrocycle adopts a chair conformation. In the complexes [Co2(Y)tpmc]ClO4)2.zH2O, (Y = phthalate or i-phthalate dianizon, z = 2; 4) it is proposed that the isomeric dicarboxylates are bonded combined as bridges and chelates. The composition and the assumed geometries of the complexes are compared with the, earlier reported, corresponding Cu(II) complexes. Cyclic voltammetry measurements showed that the compounds are electrochemically stable. Dobijeni su novi dinuklearni Co(II) kompleksi sa oktaazamakrociklicnim ligandom N,N?,N",N???-tetrakis-(2-piridilmetil)-1,4,8,11-tetraazaciklotetradekanom (tpmc) i jednim od aromaticnih mono- ili dikarboksilato liganda (benzoatom ftalatom ili izoftalatom). Oni su analizirani i okarakterisani pomocu elementalne analize (C, H, N), elektricne provodqivosti, VIS i IR spektroskopije kao i magnetnih i ciklicno voltametrijskih merewa. U [Co2(C6H5COO)2tpmc]ClO4)2.3H2O, benzoato ligandi su najverovatnije koordinovani bidentatno za svaki Co(II) u trans-polozaju, pri cemu makrociklicni ligand zauzima konformaciju stolice. U kompleksima [Co2(Y)tpmc]ClO4)2.zH2O,, (Y = ftalatni ili izoftalatni dianjon, z = 2; 4) predlozeno je da su izomerni dikarboksilati kombinovano mostovno i helatno koordinovani. Merenja ciklicnom voltametrijom su pokazala da su kompelksi elektrohemijski stabilni.