Octahedral Cadmium Research Articles

A new monomeric octahedral cadmium(II) complex based on 1,1-bis(3-methyl-4-imidazoline-2-thione)methane ligand with dye adsorption ability

A new cadmium complex with a flexible imidazolinethione ligand has been successfully synthesized. The ligand acts as a bidentate chelating molecule, resulting in the structure being a monomer. In this monomer, cadmium has an octahedral geometry coordinated by four sulfur atoms from two mbit ligands where mbit = 3,3'-methylenebis(1-methyl-1,3-dihydro-2H-imidazole-2-thione) and two oxygen atoms from the DMF molecules. The ClO 4 − anions are uncoordinated and neutralize the positive charge of the cationic complex. The title complex has a good capacity for adsorbing several organic dyes from pollutant solutions.

Exploration of photocatalytic activity of an end-on azide bridged one-dimensional cadmium(II) Schiff base complex for the degradation of organic dye in visible light

A one-dimensional polynuclear end-on azide bridged octahedral cadmium(II) Schiff base complex, [{CdL(μ-1,1-N3)}2Cd(μ-1,1-N3)2·1.76CH3OH]n {HL=2-(3-(dimethylamino)propyliminomethyl)-6-ethoxyphenol} has been synthesized and characterized by single crystal X-ray crystallography. The complex crystallizes in monoclinic space group C2/c with cell dimensions, a=21.4706(8) Å, b=9.9542(4) Å, c=19.3257(7) Å, β=103.7819(11)°. Extended supra-molecular assemblies were generated through weak non-covalent interactions. The energetic features of these interactions have also been studied by means of DFT calculations. The complex exhibits good photoluminescence in DMSO medium. The application of the complex as a photocatalyst for the decomposition of organic dye in visible light has been explored.

A combined experimental and computational study of supramolecular assemblies in two photoluminescent cadmium(II) complexes with halosalicylaldimine Schiff bases

Two new cadmium(II) complexes, [Cd(L1)(OOCCH3)(OH2)] (1), [Cd2(L2)2(μ-1,3-SCN)2(CH3OH)2] (2), have been synthesized using two halosalicylaldimine Schiff bases, HL1 and HL2 {where HL1=2-(2-(ethylamino)ethyliminomethyl)-4-bromophenol, and HL2=2-(2-(dimethylamino)ethyliminomethyl)-4-chlorophenol}, respectively. Both complexes have been characterized by elemental and spectral analysis and their structures have been confirmed by single crystal X-ray diffraction studies. Complex 1 is mononuclear and the cadmium(II) centre is apparently coordinated by a tridentate Schiff base, a water molecule and a bidentate chelating acetate. The acetate group could also be thought of as a single entity occupying just one stereochemical site as evident from the small value of chelate bite angle. Complex 2 is dinuclear and contain octahedral cadmium(II) bridged by double end-to-end thiocyanates. Supramolecular interactions in both complexes were also explored. The theoretical study, carried out using density functional theory (DFT) calculations, is devoted to the analysis of the interesting supramolecular assemblies in the solid state of the structures, paying special attention to hydrogen bonding interactions involving the coordinated solvent molecules.

Multiple crystal forms of N,N'-diacetylchitobiose deacetylase from Pyrococcus furiosus.

Native N,N'-diacetylchitobiose deacetylase from Pyrococcus furiosus (Pf-Dac) and its selenomethionine derivative (Se-Pf-Dac) were crystallized and analyzed in the presence and absence of cadmium ion. The four crystal structures fell into three different crystal-packing groups, with the cadmium-free Pf-Dac and Se-Pf-Dac belonging to the same space group, with homologous unit-cell parameters. The crystal structures in the presence of cadmium contained distorted octahedral cadmium complexes coordinated by three chlorides, two O atoms and an S or Se atom from the N-terminal methionine or selenomethionine, respectively. The N-terminal cadmium complex was involved in crystal contacts between symmetry-related molecules through hydrogen bonding to the N-termini. While all six N-termini of Se-Pf-Dac were involved in cadmium-complex formation, only two of the Pf-Dac N-termini participated in complex formation in the Cd-containing crystal, resulting in different crystal forms. These differences are discussed in light of the higher stability of the Cd-Se bond than the Cd-S bond. This work provides an example of the contribution of cadmium towards determining protein crystal quality and packing depending on the use of the native protein or the selenomethionine derivative.

Formation of three photoluminescent dinuclear cadmium(II) complexes with Cd2O2 cores

Condensation of N,N-dimethyl-1,3-diaminpropane with salicylaldehyde, 3-methoxysalicylaldehyde and 3-ethoxysalicylaldehyde produces three Schiff bases, HL1 [2-(3-(dimethylamino)propylimino)methyl)methoxyphenol], HL2 [2-(3-(dimethylamino)propylimino)methyl)-6-methoxyphenol], and HL3 [2-(3-(dimethylamino)propylimino)methyl)-6-ethoxyphenol], respectively. Addition of cadmium(II) chloride to the methanol solution of the tridentate Schiff base, HL1, produces phenoxo-bridged dinuclear cadmium(II) complex, [Cd2(L1)2(Cl)2] (1). Similarly, addition of cadmium(II) nitrate to the methanol solution of the tetradentate Schiff base, HL3, produces phenoxo-bridged dinuclear cadmium(II) complex, [Cd2(L3)2(NO3)2] (3). On the other hand, [Cd(L2)2Cd(NCO)2] (2), is produced by the addition of cadmium(II) perchlorate into the methanol solution of tetradentate Schiff base, HL2 followed by the addition of sodium cyanate. Structures of the complexes have been confirmed by single crystal X-ray diffraction studies. All complexes are dinuclear with Cd2O2 cores. Complex 1 contains square pyramidal cadmium(II) centres, whereas complexes 2 and 3 contain octahedral cadmium(II) centres. All three complexes show fluorescence.

Surface thermodynamic properties of different-sized nano octahedral cadmium molybdate

A series of nano octahedral CdMoO 4 with different sizes were prepared by reverse-microemulsion method at room temperature, and the constitute, structure and morphology were characterized. Based on the essential difference between thermodynamic properties of nano CdMoO 4 and bulk CdMoO 4 , the equations for acquiring surface thermodynamic properties of nano CdMoO 4 were derived via combining the basic theory of chemical thermodynamics with thermokinetics theory. According to the derived equations, surface thermodynamic functions such as specific surface Gibbs free energy, specific surface enthalpy and specific surface entropy of the prepared nano octahedral CdMoO 4 at 298.15 K were successfully gained by in situ microcalorimetry. Briefly, this work presented an effective and general method to obtain thermodynamic functions of nano materials.

An in vitro antibacterial and antifungal effects of cadmium(II) complexes of hexamethyltetraazacyclotetradecadiene and isomers of its saturated analogue

To evaluate the antibacterial and antifungal effects of cadmium(II) complexes with hexamethyltetraazacyclotetradecadiene ligands. Five coordinated square pyramidal cadmium(II) complexes and six coordinated square octahedral cadmium(II) complexes have been synthesized by interaction of 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene (denoted by L.2HClO4) and C-chiral isomers of its saturated analogue (denoted by 'teta' and 'tetb') with different salts of Cd(2+) ion [e.g. CdI2, Cd(NO3)2·6H2O, CdCl2·2H2O and Cd(ClO4)2·6H2O] in methanolic solution. Complexes of the ligands were investigated for antibacterial activity by disc diffusion method and antifungal effect by poisoned food technique. The newly synthesized cadmium(II) complexes of the ligands were screened as potential antimicrobial agent against a number of medically important bacteria (Staphylococcus aureus, Bacillus cereus, Salmonella typhi, Shigella dysenteriae and Escherichia coli) and against two fungi (Candida albicans and Aspergillus aculeatus). The growth inhibiting activity of the ligands and complexes against bacteria and fungi were compared with the standard antibiotic ampicillin and commercially important antifungal agent, griseofulvin respectively. Among them some of the macrocyclic complexes were found to be more fungitoxic and antibacterial than the reference antifungal drug griseofulvin and antibacterial drug ampicillin respectively. Hexamethyltetraazacyclotetradecadiene ligands and its complexes could be considered as very potential antibacterial and antifungal agent with further investigation.

Synthesis, spectral, crystal structure, thermal behavior, antimicrobial and DNA cleavage potential of two octahedral cadmium complexes: A supramolecular structure

Two new cadmium(II) complexes with the formula of CdL2(NCS)2 and CdL2(N3)2 (in which L is 2,2-dimethyl-N,N′-bis-(3-phenyl-allylidene)-propane-1,3-diamine) have been synthesized and characterized by elemental analysis, molar conductivity measurements, FT/IR, UV–Visible, 1H and 13C NMR spectra and X-ray studies. The crystal structure analysis of CdL2(NCS)2 indicated that it crystallizes in orthorhombic system with space group of Pbca. Two Schiff base ligands are bonded to cadmium(II) ion as N2-donor chelate. Coordination geometry around the cadmium ion was found to be partially distorted octahedron. The Cd–Nimine bond distances are found in the range of 2.363(2)–2.427(2)Å while the Cd–Nisothiocyanate bond distances are 2.287(2)Å and 2.310(2)Å. The existence of C–H⋯π and C–H⋯S interactions in the CdL2(NCS)2 crystal leads to a supramolecular structure in its network. Then cadmium complexes were screened in vitro for their antibacterial and antifungal activities against two Gram-negative and two Gram-positive bacteria and also against Candida albicans as a fungus. Moreover, the compounds were subjected for DNA-cleavage potential by gel electrophoresis method. Finally thermo-gravimetric analysis of the complexes was applied for thermal behavior studies and then some thermo-kinetics activation parameters were evaluated.

Variation in molecular and crystalline architectures of di- and poly-nuclear cadmium(II) complexes on changing the denticity of the blocking ligands

Three cadmium(II) complexes, [Cd(dmpn)(μ-1,1-N3)2]n (1), [Cd(L1)2Cd(N3)2] (2) and [Cd2(L2)2(Cl)2] (3) {where dmpn is a bidentate chelating ligand N,N-dimethyl-1,3-diaminopropane, HL1 is a tetradentate Schiff base 2-((3-(dimethylamino)propylimino)methyl)-6-methoxyphenol and HL2 is a tridentate Schiff base 2-((2-(diethylamino)ethylimino)methyl)phenol}, were prepared and characterised by elemental analysis, IR, UV–Vis 1H NMR and fluorescence spectroscopy, and single crystal X-ray diffraction studies. Complex 1 is polynuclear with double end-on azide bridges. The hydrogen bonding in complex 1 produces a three-dimensional supramolecular network. Complex 2 is dinuclear and contains octahedral cadmium(II) centres. Complex 3 is also dinuclear, but contains square pyramidal cadmium(II) centres. Intramolecular C–H⋯π interactions are present in complex 2. There is no supramolecular interaction in complex 3. The variation in the denticity of the ligands causes changes in the molecular and crystalline architectures of the complexes. All the three complexes show fluorescence.

A 3D Porous Coordination Polymer from Tetrazole Ligand and Cd(II): Crystal Structure, Luminescent Property and Adsorption of Methanol and Water

An unusual tetrazole-based Cd(II) coordination polymer, [Cd(4-tzba)(H2O)]n (tzba = 4-(tetrazolyl)benzenecarboxylic acid) (1), was synthesized by hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. The structure of 1 contains distorted octahedral cadmium centers coordinated by four different tzba2− ligands and a water molecule. All the tzba2− ligands display coordination of type, μ4-κN1:κN3:κN4:κO1, O2, which connects four Cd(II) atoms to form an intricate 3-D network. There are three kinds of apertures in the structure of 1; two helical channels and a hexagonal aperture are observed along different axes. Polymer 1 exhibits selective gas adsorption behavior for methanol, ethanol and water. In addition, 1 shows blue photoluminescence mainly arising from intraligand transitions of the aromatic rings in the tbza2− ligand.

Pyrimidyl-2-selenolates of cadmium and mercury: Synthesis, characterization, structures and their conversion to metal selenide nano-particles

Reactions of [MCl2(tmeda)] (M=Cd or Hg; tmeda=N,N,N′,N′-tetramethylethylenediamine) with NaSeC4H(R-4,6)2N2 (R=H or Me) gave selenolate complexes of the general formula [M{SeC4H(R-4,6)2N2}2(tmeda)n] (M/R/n=Cd/H/1 (1); Cd/Me/1 (2); Hg/H/1 (3) and Hg/Me/0 (4)). The chloro complexes of general formula, [MCl{SeC4H(Me-4,6)2N2}(tmeda)] (M=Cd (6) or Hg (7)) have been synthesized by redistribution reaction of [M{SeC4H(Me-4,6)2N2}2] with MCl2 followed by treatment with tmeda. The complexes have been characterized by elemental analysis, UV–Vis and NMR (1H, 13C, 77Se, 113Cd and 199Hg) spectroscopy. The molecular structures of [Cd{SeC4H(Me-4,6)2N2}2(tmeda)] and [Hg{SeC4H(Me-4,6)2N2}2] were established by single crystal X-ray diffraction. The complex, [Cd{SeC4H(Me-4,6)2N2}2(tmeda)] comprises of an octahedral cadmium atom containing chelating, two SeC4H(4,6-Me)N2 and one tmeda, ligands. The complex, [Hg{SeC4H(Me-4,6)2N2}2] has a linear structure with monodentate selenolate ligand. Thermolysis of [Cd{SeC4H(Me-4,6)2N2}2(tmeda)] and [Hg{SeC4H(Me-4,6)2N2}2] in various coordinating solvents afforded CdSe and HgSe nanoparticles which were characterized by UV–Vis, XRD, SEM, EDX and TEM.

4′-(pyridyl)-2,2′:6′,2″-Terpyridine ligands: discrete metal complexes and their polymeric assemblies as a function of N-pyridyl substitution patterns

The syntheses and structures of a series of Cd(II) and Co(II) complexes of 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine (L1) and 4′-(3-pyridyl)-2,2′:6′,2″-terpyridine (L2) are discussed. In each case, the reaction was carried out in a 1:1 stoichiometry and the terpyridine (tpy) acts as a tridentate chelating ligand. The M:L stoichiometries found in the crystalline products and the structural role played by the 3-pyridyl or 4-pyridyl tpy substituents show subtle differences. On reaction with CdCl2, L1 generates a 1D directional polymer via metal coordination through its 4-pyridyl substituent (1). On reaction with Cd(NO3)2, however, the 4-pyridyl unit of L1 engages in structurally significant H-bonding to a coordinated CH3OH (2). On reaction with CdBr2, L2 forms a discrete 5-coordinate monomeric crystal (3) with dormant 3-pyridyl substituent, whereas reaction with Cd(ClO4)2 produces an intriguing polymeric array (4) {Cd3(L2)4}. This comprises a {Cd(tpy)2}-subunit that engages in a terpyridine embrace and bridges two other octahedral cadmium metal atoms. The reaction of L2 with CoCl2 produces a discrete Co3(L2)2 complex (5) in which two pentavalent {Co(tpy)Cl2} units are connected via a tetrahedrally coordinated cobalt metal centre.

Monomeric pyridyl-2-selenolate complexes of cadmium and mercury: Synthesis, characterization and their conversion to metal selenide nanoparticles

Reactions of [MCl 2(tmeda)] (M = Cd or Hg; tmeda = N,N,N′,N′-tetramethylethylenediamine) with M ′SeC 5H 3(R-3)N (R = H or Me) gave selenolate complexes of the general formula [M{SeC 5H 3(R-3)N} 2(tmeda) n ] (M/R/ n = Cd/H/1 ( 1); Cd/Me/1 ( 2); Hg/H/1 ( 3) and Hg/Me/0 ( 4)). The complexes were characterized by elemental analysis, UV–Vis and NMR ( 1H, 13C, 77Se, 113Cd and 199Hg) spectroscopy. The crystal structures of {SeC 5H 3(Me-3)N} 2, [M(SeC 5H 4N) 2(tmeda)] (M = Cd or Hg) and [Hg{SeC 5H 3(Me-3)N} 2] were established by single crystal X-ray diffraction. The complex, [Cd(SeC 5H 4N) 2(tmeda)] comprises of an octahedral cadmium atom containing three chelating, two SeC 5H 4N and one tmeda, ligands. The corresponding mercury complex adopts a severely distorted tetrahedral configuration defined by the two-monodentate selenolate and chelating tmeda. The complex, [Hg{SeC 5H 3(Me-3)N} 2] has a linear structure with monodentate selenolate ligand. The cadmium complexes undergo a two-step decomposition (TGA) leading to the formation of CdSe. Thermolysis of [Cd{SeC 5H 3(R-3)N} 2(tmeda) n ] in hexadecylamine (HDA)/tri- n-octylphosphineoxide (TOPO) yields CdSe nanoparticles, which were characterized by UV–Vis, XRD, SEM and TEM (in part).

Direct chemical and electrochemical syntheses of coordination compounds of benzazolyl azo ligands

The chelates of 2-hydroxy(aminophenylnaphthyl)-azo-1-alkylbenzimidazoles were obtained from electrochemical (anodic dissolution of zero-valent d-metals) and chemical (from acetates of the same metals) syntheses in methanol. The EXAFS and X-ray single crystal diffraction data revealed the existence of octahedral nickel, zinc, and cadmium complexes containing four five-membered metallocycles with the N4О2 or N6 ligand environments. The formation of five-membered coordination units, non-typical for azo ligands, is explained on the basis of inner-chelate competitive metal binding of ambidentate ligand systems.

Coordination modes of 3-hydroxypicolinic acid (OH-picH): Synthesis and characterization of cadmium(II) complexes: Crystal and molecular structures of [CdX(OH-pic)(OH-picH)(H 2O)] 2 X = Cl −, Br −

Two complexes of 3-hydroxypicolinic acid and cadmium(II) chloride and bromide, namely di-μ-halo-[aqua-(3-hydroxypyridine-2-carboxylato- N, O)(3-hydroxypyridinium-2-carboxylato- O)cadmium(II)], halo = Cl − ( 1), Br − ( 2) have been prepared and characterized by spectroscopic, thermal and X-ray crystallographic methods. The IR and thermal data correlate with the structures of the complexes in the solid state. The vibration bands of diagnostic value are compared to the values of the free acid. The complexes 1 and 2 are isostructural. The molecular structures of complexes 1 and 2 comprise centrosymmetrical dimers formed via di-μ-halide bridges. The distorted octahedral cadmium coordination environment contains two halide atoms, one water molecule and two 3-OH-pic ligands, one bonded to the cadmium ion in a monodentate mode through the carboxylate O atom and the other in the bidentate N, O-chelated mode forming a five-membered chelate ring. An extensive network of the O–H⋯O and N–H⋯O hydrogen bonds are found. From 1H and 13C NMR measurements it was determined that in dimethylformamide solution complexes 1 and 2 do not exist. Cd(OH-pic) 2 is the only compound that was identified instead.

Syntheses and crystal structures of two new coordination polymers of Cd(II) using organic spacer and inorganic-bridging ligands

Two new cadmium (II) complexes [Cd(hmt)(dca)2] n (1) and [Cd3(hmt)2(SeCN)6(H2O)2] n (2) (hmt=hexamethylenetetramine, dca=dicyanamide) have been synthesized and characterized by X-ray single-crystal analysis. The complex 1 is a 2D rectangular grid of octahedral cadmium (II) with CdN6 chromophore where cadmium centers are doubly bridged by dicyanamide and hmt along a-axis, which are interlinked by dicyanamide running along c-axis. Whereas, complex 2 is a 1D chain of octahedral cadmium (II) with a three-leg ladder topology running along a-axis. The Cd(II) centers are doubly bridged through SeCN (infinite rail) along a-axis and singly bridged by hmt (two-step rung) along c-axis, having cadmium centers with CdSe2N3O and CdSe2N4 chromophores. The adjacent chains through H-bonding between coordinated water and hmt, and Se $$\cdots$$ Se interaction are extended to 2D supramolecular architecture.

Experimental Evidence for a Variable First Coordination Shell of the Cadmium(II) Ion in Aqueous, Dimethyl Sulfoxide, and N,N‘-Dimethylpropyleneurea Solution

A combined extended X-ray absorption fine structure (EXAFS) and large angle X-ray scattering (LAXS) investigation has been performed to evaluate the coordination structure of the cadmium(II) ion in aqueous, dimethyl sulfoxide, and N,N'-dimethylpropyleneurea (dmpu) solutions. This approach has singled out the existence of a flexible coordination shell around the cadmium(II) ion in aqueous and dimethyl sulfoxide solutions, whereas a regular octahedral complex is detected in dmpu. The EXAFS and LAXS techniques provide different values of the Cd-O first shell distance (2.27(1) A and 2.302(5) A, respectively) for the hydrated and dimethyl sulfoxide solvated complexes, and this discrepancy is originated by the simultaneous presence of hexa- and heptacoordinated complexes in solution, giving rise to a broad distribution of distances around the ion. These findings demonstrate that, in solution, the cadmium(II) ion forms quite flexible hydration and dimethyl sulfoxide solvate complexes undergoing a solvent exchange with unusually stable seven-coordinated intermediate complexes, and therefore the mean ion-solvent distance is longer in solution than in the solid state. In the dmpu solution, due to the bulkiness of the solvent molecules, the octahedral cadmium(II) solvate is extremely crowded and it is not possible for a seventh ligand to enter the inner-coordination shell. This investigation shows that the combined analysis of the EXAFS and LAXS data allows a reliable determination of the structural properties of electrolyte solutions, also in the presence of flexible coordination shell with a variable number of coordinating molecules.

The R21(6) hydrogen-bonded synthon in neutral urea and metal-bound halide systems

The recurrence of the R21(6) motif between urea and metal bound halides is explored through studies in the CSD, including examples of the closely related thiourea and guanidine-based structures. A series of compounds containing the isomeric pyridyl–urea ligands 1 and 2 attached to trans-dihalide metal units have been prepared and their X-ray crystal structures determined. A hydrogen-bonding motif between the metal-bound halide ligands and the urea groups on the pyridyl ligands is observed in most cases which takes the form of an R21(6) ring. Three copper(II) complexes, [Cu(2)2Cl2]·2MeOH 3, [Cu(2)2Br2(MeOH)] 4 and [Cu(2)2Cl2(EtOH)] 5 all retain this supramolecular synthon despite a changing coordination environment and alteration of the halide ligands. A series of solvates of the complex [Pd(1)2Cl2] (6–8) shows that the R21(6) synthon does not occur in the presence of strongly hydrogen-bond accepting solvents such as DMF (6) and MeCN (7) but is observed in the presence of the hydrogen bond donor solvent methanol (8). The motif also occurs within an octahedral cadmium system [Cd(1)4Cl2]·2H2O·2MeCN 9. In all cases in which the R21(6) synthon is observed chain-like structures form between the metal complexes. Two contrasting structures based around tetrahedral zinc(II) centres [Zn(1)2Cl2] (10) and [Zn(1)2I2]·0.5MeOH (11) do not display the bifurcated synthon, showing instead an R22(8) motif in the case of 10 or no ring-type halide interaction in 11.

Three new thiocyanato-bridged complexes of cadmium(II): syntheses, X-ray crystal structures and thermal properties

Three new thiocyanato-bridged polymers of cadmium(II), [Cd(me4dpt)(SCN)2] n (1) [me4dpt = 3,3′-iminobis(N,N-dimethylpropylamine], [Cd(me2tn)(SCN)2] n (2) (me2tn = N,N′-dimethyl-1,3-propanediamine) and [{amphyH} {Cd(SCN)3}] n (3) (ampyH = 4-aminopyridinium cation), have been synthesized and their molecular structures determined through X-ray crystallography. In Complex 1 each square pyramidal mononuclear fragment is H-bonded (N − H…S) to form a 1D supramolecular chain. Complex 2 is a 1D coordination polymer in which each distorted octahedral cadmium(II) ion is linked with the four bridging thiocyanates and one diamine. The structure of 3 reveals anionic [Cd(SCN)3]− zigzag chains arranged in an approximately hexagonal array with the 4-aminopyridinum cations occupying triangular channels. Each chain is H-bonded (N−H…N) to form a 2D supramolecular network. Upon heating, 1 and 2 melt and transform to transparent solid masses at ambient temperature over a few days. On scratching, these turn to a fine powder. This phenomenon is repeatable. Complex 3 upon heating loses a 4-aminopyridine molecule and transforms to [H][Cd(SCN)3] at ˜ 195°C.

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)Cl2]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(II) acts as a branching centre. [Cd(L)Br2]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)I2]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 °C, ΔH = 29.5 kJ mol−1 for (1); 83–128 °C, ΔH = 22.5 kJ mol−1 for (2) and 91–128 °C, ΔH = 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 ≈ 60%) for several days but exhibit a glass transition upon heating.