Syntheses, crystal structures and thermal properties of 3D coordination polymers assembled from 1,4,5,8-naphthalenetetracarboxylic acid

Two new coordination polymers based on 1,4,5,8-naphthalenetetracarboxylate (ntc) has been prepared by hydrothermal methods. Their crystal structures have been determined from synchrotron powder X-ray diffraction data. Ca2(C14H4O8)(H2O)2, CPO-13, is built around infinite chains of seven coordinated calcium atoms. Zn2(C14H4O8)(H2O)2, CPO-14, is isostructural with Mn2(C14H4O8)(H2O)2, and is built around infinite chains of corner sharing Zn octahedra. Crystal data for CPO-13: Triclinic space group P-1  , with a=5.820a=5.820, b=6.759b=6.759, c=10.168 Åc=10.168 Å, α=72.32°α=72.32°, β=86.09°β=86.09°, γ=107.74°γ=107.74°, V=357.310 Å3V=357.310 Å3 and Z=1Z=1. Crystal data for CPO-14: Orthorhombic space group Pbam  , with a=9.773a=9.773, b=7.060b=7.060, c=9.879 Åc=9.879 Å, V=681.729 Å3V=681.729 Å3 and Z=2Z=2. The thermal properties were investigated for both compounds. An unusual anisotropic thermal expansion for CPO-14 is caused by the carboxylate groups of the ntc anions gradually bending away from each other.

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