Phthalate ligand has been extensively studied as a multifunctional ligand
for supramolecular compounds [1]. In new nickel(II) compound [Ni(1,2-
bdc)2(H2O)4](PipH2)(H2O)8 (1) each Ni(II) centre is coordinated with one O atom
of two residues of 1,2-bdc (Ni–O5=2.048, Ni–O9=2.044 Å) and four O atoms
of water molecules (Ni–O1=2.088, Ni–O2=2.048, Ni–O3=2.108 Ni–O2=2.067
Å). Structure is completed by uncoordinated protonated piperazine molecule
and 8 water molecules (Fig.1). Compound 1 shows the system of expected
intramolecular H-bonds and further the discrete units are held together by

intermolecular N-H…O(water) and N-H…O(carboxylate) hydrogen bonds forming
a 2D-network. The centro symmetric solvate water molecules form T4(2)6(2)
[2] H-bonded tapes situated in inner voids Fig.1. Packing diagram of 1. (Fig.2). The O
atoms of the water molecules form planar 4-membered rings and the 6-membered
rings display a chain conformation. C o m p o u n d 1 Fig.2. H-bonded water tape in 1. shows a potential use for gas storage due to its porosity. Unfortunately removing of water molecules results to the loss of crystal structure what was demonstrated by TGA and XPD analyses of 1 and its dehydrated form.
Acknowledgement. This work was supported by CRDF-MRDA (No. MTFP-04)
and INTAS (No.03-51-4532) grants.
1. S.G. Baca, et al. Inorg.Chim.Acta, 357, 2004, P. 3419-3429.
2. L. Infantes, S. Motherwell Cryst. Eng. Comm., 4(75), 2002, P. 454–461.