Two heterometallic complexes with a new macrocyclic oxamido complex ligand

A new macrocyclic oxamido-nickle(II) complex Na2NiL was synthesized. L denotes the doubly deprotonated forms of (13Z, 19Z)-16-methyl-6,7-dioxo-5,6,7,8-tetrahydrotriben-zo[b,f,l][1,4,8,11]tetraazacyclotetradecine- 13,20-dicarboxylate. Based on the complex ligand Ni(L2–), two heterometallic complexes [Ca2(NiL)2(H2O)8] · 10H2O (I) and [Co(NiL)2(H2O)2][Co(H2O)6] · 2.8H2O (II) were prepared. X-ray single crystal analyses (CCDC nos. 914618 (I), 914616 (II)) revealed that [Ca2(NiL)2(H2O)8] in I is a molecular box and the trinuclear complex anion [Co(NiL)2(H2O)2]2–in II is centrosymmetric. Thermogravimetric analyses showed that I exhibited moderately good stability and Co(II) catalyzed the thermal decomposition of II.