Albert Escuer, Ramon Vicente, Sujit B Kumar, Xavier Solans and Mercé Font-Bardía
The trinuclear compound [Ni2(µ-CO3)(dmpd)4(H2 O)][Ni(dmpd)2(H2O)2][ClO4 ]4·H2O was obtained from the reaction of basic solutions of nickel(II) perchlorate and 2,2-dimethylpropane-1,3-diamine (dmpd) with atmospheric CO2. It crystallises in the orthorhombic system, space group Pcab, with a = 18.634(10), b = 25.447(8), c = 25.598(4) Å, Z = 8, R = 0.0437. The three nickel atoms show octahedral co-ordination with three different environments, Ni(CO3-O,O′)(dmpd)2, Ni(CO3-O″)(dmpd)2(H2O) and Ni(dmpd)2(H2O)2. The carbonate anion acts as a bridge between two nickel ions whereas the [Ni(dmpd)2(H2O)2]2+ subunit is linked by hydrogen bonds to the dinuclear group. The dinuclear [Ni2(µ-CO3)(dmpd)4(H2O)] 2+ subunit shows a moderately weak antiferromagnetic coupling with a J value of -7.8 cm-1. The tridentate co-ordination mode found in the carbonate ligand has not previously been reported for nickel. Its magnetic behaviour is discussed.