Hydroxamate based transition metal-organic coordination polymers with semiconductive properties

In addtion to carboxylate and N-donor linkers, hydroxamates are a kind of new emerging ligand to form coordination polymers. However, owing to the difficulty in controlling reversible formation of strong...

Slight ligand modifications within multitopic linear hydroxamates promotes connectivity differences in Cu(ii) 1-D coordination polymers

Two novel hydroxamic acids have been used in constructing two 1-D coordination polymers. Slight structural differences promote connectivity changes upon Cu(ii) metalation as rationalised using DFT calculations and Hirschfeld surface analysis.

Mono- and ditopic hydroxamate ligands towards discrete and extended network architectures

A family of mono- and ditopic hydroxamic acids has been employed in the synthesis and structural and physical characterisation of discrete (0D) and (1- and 2-D) extended network coordination complexes. Examples of the latter include the 1-D coordination polymer {[Zn(ii)(L₃H)₂]·2MeOH}_n (5; L₃H₂ = 2-(methylamino)phenylhydroxamic acid) and the 2-D extended network {[Cu(ii)(L₂H)(H₂O)(NO₃)]·H₂O}_n (5; L₂H₂ = 4-amino-2-(acetoxy)phenylhydroxamic acid). The 12-MC-4 metallacrown [Cu(ii)₅(L₄H)₄(MeOH)₂(NO₃)₂]·3H₂O·4MeOH (7) represents the first metal complex constructed using the novel ligand N-hydroxy-2-[(2-hydroxy-3-methoxybenzyl)amino]benzamide (L₄H₃). Variable temperature magnetic susceptibility studies confirm strong antiferromagnetic exchange between the Cu(ii) centres in 7. Coordination polymer 5 shows photoluminescence in the blue region (λ_PL∼ 421-450 nm) with a bathochromic shift of the emission (∼15-30 nm) from solution to the solid state.

Low temperature heat capacity, standard entropy, standard enthalpy and magnetic property: a new 1D CuII coordination polymer incorporating tetrazole-1-acetic acid and p-nitrobenzoic acid

A new 1D Cu^II coordination polymer, formulated as {[Cu(TZA)(PNA)]·H₂O}_n (1) (HTZA = tetrazole-1-acetic acid, HPNA = p-nitrobenzoic acid), was synthesized and structurally characterized. Thermogravimetric analysis demonstrated that the main frame of 1 exhibited good thermostability up to 473 K. The non-isothermal kinetics for the first exothermic process of 1 were studied by Kissinger and Ozawa methods. The magnetic study revealed that 1 possessed antiferromagnetic exchange interactions between Cu^II ions through the carboxyl-bridge. The low-temperature (1.9 to 300 K) heat capacity of 1 was measured using the heat-capacity option of a Quantum Design Physical Property Measurement System (PPMS). In addition, the thermodynamic functions in the experimental temperature range were derived by fitting the heat-capacity data to a series of theoretical and empirical models. The standard entropy and standard enthalpy of 1 were respectively calculated to be 411.37 ± 4.11 J mol^-1 K^-1 and 60.21 ± 0.60 kJ mol^-1.