Flexibility in co-ordinative behaviour of N-(3-hydroxypropyl)ethane-1,2-diamine toward cadmium(II) halides:: syntheses, crystal structures and solid state thermal studies

One new two-dimensional and two one-dimensional organic/inorganic composite coordination polymers have been synthesised by the reaction of cadmium(II) halides with N-(3-hydroxypropyl) ethane-1,2-diamine (L) and structurally characterised. [Cd(L)Cl-2](n) (1) is a two-dimensional sheet which is built from intersecting zigzag chains and forms a honeycomb like (6,3) net where each octahedral cadmium is linked with two bridging chloride atoms, one pendant chloride atom, two chelated nitrogen atoms of L and an oxygen atom from a neighbouring ligand; each cadmium() acts as a branching centre. [Cd(L) Br-2](n) (2) is a bromo bridged one-dimensional chain in which the non-chelated part of ligand L binds a neighbouring cadmium(II) centre resulting in an alternating array of four- and twelve-membered rings. [Cd( L) I-2](n) (3) is an iodo bridged one-dimensional network of alternating octahedral (CdN4I2) and tetrahedral cadmium(II) (CdI4) centres. Upon heating the complexes exhibit an irreversible endothermic phase transition [95-133 degreesC, DeltaH = 29.5 kJ mol(-1) for (1); 83-128 degreesC, DeltaH = 22.5 kJ mol(-1) for (2) and 91-128 degreesC, DeltaH = 15.5 kJ mol(-1) for (3)] yielding transparent films of CdLCl2 (1a), CdLBr2 (1b) and CdLI2 (1c) respectively. The derived species (1a, 1b and 1c) do not revert on keeping them in a humid atmosphere (relative humidity approximate to60%) for several days but exhibit a glass transition upon heating.