Synthesis and crystal structures of zinc(II) coordination polymers of trimethylenedipyridine (tmdp), 4-nitrobenzoic (Hnba) and 4-biphenylcarboxylic acid (Hbiphen) for adsorptive removal of methyl orange from aqueous solution

Two novel Zn(II) coordination polymers (CPs), [Zn(nba)2(tmdp)]n (1) and [Zn(biphen)2(tmdp)]n (2), were synthesised by reacting Zn(NO3)2·6H2O and 4,4′-trimethylenedipyridine (tmdp) with corresponding carboxylates: 4-nitrobenzoic (Hnba) and 4-biphenylcarboxylic acid (Hbiphen). Their structures were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Compounds 1 and 2 are one-dimensional CPs with the zinc(II) carboxylate units bridged through the N-donor spacer ligand. The zinc (II) atom adopts a tetrahedral arrangement in 1 and 2 coordinated by two nitrogen atoms from two tmdp ligand molecules and two deprotonated oxygen atoms from two carboxylate ligand molecules. The adsorption capacities of MO in this study was found to be 546.31 mg/g and 22.67 mg/g for 1 and 2, respectively. DFT studies confirmed that adsorption is primarily due to π-π stacking and electrostatic interactions between MO and 1. It is noteworthy that binding energy (BE) values for 1 (-74.14 KJ/mol) and 2 (-61.11 KJ/mol) correlate reasonably well with the observed adsorption capacities of MO. The study demonstrated that 1 has higher adsorption efficiency in comparison to 2 and could be an effective and easily reusable adsorbent for the removal of MO from wastewater

Intimate partner abuse: wife beating among civil servants in Ibadan, Nigeria

Wife beating is one of the most common forms of violence against women by husbands or other intimate male partners. Although violence against women is pervasive, there are only few studies documenting the magnitude of the problem especially among the working class. The civil service comprises of persons from all socio-economic levels and different backgrounds. They act in advisory capacity and assist those responsible for making state policy. Thus, 431 civil servants of the Oyo State government service were interviewed using a 44-item self-administered questionnaire. Results revealed that prevalence of wife beating was 31.3%. Ninety one (42.5%) men had been perpetrators, while 44 (23.5%) women had been victims. Consuming alcohol and growing up in an environment where parents fight publicly were significantly associated (p < 0.05) with men beating their wives; while being young, unmarried and a parental background of fighting was significantly associated with women being beaten (p < 0.05). Female respondents justified reasons for various types of domestic violence, including beating, more than the males (p < 0.05). Younger respondents had significantly worse attitudes (p < 0.05), while married and educated respondents had better attitude (p < 0.05). “Not wanting the children to suffer” (60.7%) and “hoping that partner will change” (28.8%) were reasons given for remaining in abusive relationships. There is an urgent need for education of the women on their rights, sensitisation of the men on gender-based violence and punishment for perpetrators. Supportive care and counselling services should also be provided for victims of violence. African Journal of Reproductive Health Vol. 9(2) 2005: 54-6

Photocatalytic degradation of methylene blue using sunlight-powered coordination polymers constructed from a tetracarboxylate linker

Here, we report the preparation of three coordination polymers - [Mn2(btec)]n, 1; [Ce2(H2btec)(btec)(H2O)2]n, 2; and [Fe(Hbtec)(H2O)2]n 3 from 1,2,4,5-benzenetetracarboxylic acid (H4btec). Physicochemical characterization of the coordination polymers were undertaken using microanalysis, X-ray crystallography, FTIR, PXRD, TGA/DSC, and UV/visible spectrophotometry to confirm the identities of the compounds. The Mn(II) centres in 1 exhibit octahedral geometry coordinated by six oxygen atoms and crystallizes in the monoclinic space group I2/m. In 2, Ce(III) centres adopt tricapped trigonal prism geometry, coordinated by three btec4-, three from H2btec2- and the oxygen from one coordinated water molecule. It crystallizes in the triclinic space group P . 3 is composed of an Hbtec ion and two water molecules coordinated to the Fe (III) ion. The band gaps of 1, 2, and 3 are 2.87, 3.10, and 3.61 eV, respectively, while their hydrogen peroxide-assisted efficiencies for the photodegradation of methylene blue are 91, 94, and 100 % respectively. An active species trapping experiment showed that an increase in hydroxy radicals (•OH) explains the enhanced efficiencies and provide an insight into the mechanism of the photodegradation of methylene blue by the photocatalysts. Efficiencies of mixtures of 2/H2O2 and 3/H2O2 reduced only slightly over five cycles of use and PXRD data revealed that 2 and 3 were chemically stable over the three cycles. Overall, the coordination polymers could serve as potential candidates for industrial-scale methylene blue degradation in the aqueous phase

Calcium coordination compounds of anionic forms of hydrogen dipicolinate and quinolinate : synthesis, characterization, crystal structures and DFT studies

Two calcium coordination compounds [Ca(2,6-Hpdc)2(H2O)2] 1 and [Ca2(2,3-pdc)2(H2O)6]n 2 (where 2,6-H2pdc = 2,6-pyridinedicarboxylic acid and 2,3-H2pdc = 2,3-pyridinedicarboxylic acid) were grown at room temperature. The compounds were characterized using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, powder X-ray diffraction and single crystal X-ray crystallographic analysis. The structures of both compounds are stabilized by a network of hydrogen bonds arising from coordinated water molecules and carboxylate groups. Computational analysis revealed that compound 1 has a large energy gap (9.221 eV), suggesting high excitation energies and chemical hardness making it a better electron acceptor while compound 2 displayed a smaller energy gap (5.156 eV), which is indicative of a softer molecule with better polarizability and reactivity

A zinc-based coordination polymer as adsorbent for removal of trichlorophenol from aqueous solution : synthesis, sorption and DFT studies

[Zn(hba)2(tmdp)]n (1), a Zn-coordination polymer (CP), prepared by the reaction of Zn(NO3)2•6H2O, 4-hydroxybenzoic acid (Hhba) and 4,4’- trimethylenedipyridine (tmdp) was reported. The compound was characterised, using CHN, single crystal and powder X-ray diffraction analysis, FT-IR, and TGA techniques. It exhibits a square pyramidal geometry, with the zinc (II) atom coordinated to two nitrogen atoms from two tmdp ligand molecules and to three oxygen atoms from two hba molecules. The zinc (II) carboxylate units are bridged through the N-donor spacer ligand, thereby giving rise to a one-dimensional CP. PXRD analysis confirmed the purity of the bulk of (1). Compound (1) presented an adsorption capacity of 207.8 mg/g for the removal of 2,4,6-trichlorophenol (TCP) from aqueous solution. The adsorption mechanism is governed by π-π stacking and electrostatic interactions, as obtained from DFT studies. The feasibility and exothermic nature of the adsorption process is indicated by the negative binding energy obtained

Synthesis, structural and DFT investigation of Zn(nba) 2 (meim) 2 for adsorptive removal of eosin yellow dye from aqueous solution

A novel Zn(II) mixed‐ligand complex, Zn(nba)2(meim)2 (1), synthesized from Zn(NO3)2.6H2O, nitrobenzoic acid (Hnba) and 1‐methylimidazole (meim) is reported. The complex was characterized by elemental analysis, FT‐IR, powder and single crystal X‐ray crystallography and TGA/DSC. 1 exhibits a tetrahedral geometry for Zn(II), which is coordinated to two carboxylate oxygen atoms from two nba anions and two imidazole nitrogen atoms from two meim molecules. Thermal analysis shows the stability of 1 up to 260 °C. The adsorption of eosin yellow (EY) dye on 1 was investigated. The adsorption capacity of 1 for EY amounted to 65.32 mg/g, fitting best into Langmuir isotherm and pseudo second order kinetic models. From DFT studies, it was determined that adsorption is predominantly due to electrostatic, hydrogen bonding and π‐π interactions

Biosynthesis of Functional Silver Nanoparticles Using Callus and Hairy Root Cultures of <i>Aristolochia manshuriensis</i>

This study delves into the novel utilization of Aristolochia manshuriensis cultured cells for extracellular silver nanoparticles (AgNPs) synthesis without the need for additional substances. The presence of elemental silver has been verified using energy-dispersive X-ray spectroscopy, while distinct surface plasmon resonance peaks were revealed by UV-Vis spectra. Transmission and scanning electron microscopy indicated that the AgNPs, ranging in size from 10 to 40 nm, exhibited a spherical morphology. Fourier-transform infrared analysis validated the abilty of A. manshuriensis extract components to serve as both reducing and capping agents for metal ions. In the context of cytotoxicity on embryonic fibroblast (NIH 3T3) and mouse neuroblastoma (N2A) cells, AgNPs demonstrated varying effects. Specifically, nanoparticles derived from callus cultures exhibited an IC50 of 2.8 µg/mL, effectively inhibiting N2A growth, whereas AgNPs sourced from hairy roots only achieved this only at concentrations of 50 µg/mL and above. Notably, all studied AgNPs’ treatment-induced cytotoxicity in fibroblast cells, yielding IC50 values ranging from 7.2 to 36.3 µg/mL. Furthermore, the findings unveiled the efficacy of the synthesized AgNPs against pathogenic microorganisms impacting both plants and animals, including Agrobacterium rhizogenes, A. tumefaciens, Bacillus subtilis, and Escherichia coli. These findings underscore the effectiveness of biotechnological methodologies in offering advanced and enhanced green nanotechnology alternatives for generating nanoparticles with applications in combating cancer and infectious disorders