Four configurationally and conformationally related Zn（II） complexes with a tridentate ligand namely, N-（2-pyridylmethyl）-phenylalanine （Hpmpa）, have been synthesized by hydrothermal reactions. [Zn（L-α-pmpa）2·HaO] 1： orthorhombic, space group P21212 with a = 15.1091（7）, b = 16.2417（8）, c = 5.9972（3） A, V= 1471.70（12）A^3, Z = 2, Mr = 593.97, Dc = 1.340 g/cm^3,μ = 0.879 mm^-1, F（000） = 620, Rint= 0.0205, R = 0.0450 and wR = 0.1578 for 3102 observed reflections with I 〉 2σ（I）; [Zn（D-α-pmpa）2·2H2O] 2： orthorhombic, space group P21212 with a = 15.1023（6）, b = 16.2516（7）, c = 6.0024（2）A, V= 1473.21（10）A^3, Z = 2, Mr = 611.98, Dc = 1.380 g/cm^3,μ = 0.882 mm^-1, F（000） = 640, Rint= 0.0337, R = 0.0484 and wR = 0.1435 for 2408 observed reflections with I 〉 2σ（I）; [Zn（L-β-pmpa）2] 3： monoclinic, space group C2/c with a = 27.8667（5）, b = 5.60350（10）, c = 19.9636（2）A β = 120：2210（10）°, V = 2693.66（7）A^3, Z = 4, Mr = 575.95, De= 1.420 g/cm^3,μ = 0.955 mm^-1, F（000） = 1200, Rint= 0.0345, R = 0.0358 and wR = 0.1135 for 2251 observed reflections with I 〉 2σ（I）; and [Zn（D-β-pmpa）2] 4. They are all mononuclear discrete structures. The influence of temperature and pH on the conformation of structures has been investigated. Moreover, the photoluminescent properties of compounds 1 and 3 are also reported.
Two coordination polymers have been synthesized from cpg/4,4＇-bipy/metal ions reaction system, [Zn（cpg）（4,4＇-bipy）0.5（H2O）]·H2O 1 and [Cd（cpg）（4,4＇-bipy）0.5（H2O）2]·H2O 2. X- ray analyses show that different coordination geometries of zinc and cadmium ions lead to similar ladder structures （tetra-for zinc ion and hexa- for cadmium ion）, in which all the flexible cpg molecules exist as single conformations of anti-form.
