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Direct mixing (de novo) and Solvent Assisted Ligand Exchange (SALE) are the main methods used for the synthesis of Mixed-Linker Zeolitic Imidazolate Frameworks (ML-ZIFs). ML-ZIFs with combined –NO2 and –Br/–Cl functionalities were prepared via both synthetic routes. Thereafter the CO2 uptake of the ML-ZIFs were compared, as well as their abilities to fixate CO2 with epoxide substrates. The de novo synthesis resulted in ML-ZIFs with SOD topologies, 60: 40 (–NO2: –Br/–Cl) functionality ratios, higher porosities, better thermal stability and higher CO2 uptake than equivalent SALE products. SALE resulted in smaller ML-ZIF crystallites, only ~ 10% incorporation of –Br/–Cl functionalized imidazolate linkers, and phase change during activation. ML-ZIF-7Cl, obtained from direct mixing, resulted in the highest CO2 uptake (90 cm3 g−1), in line with its higher porosity. ML-ZIF-7Cl, in combination with tetrabutylammonium bromide (TBAB), showed a high catalytic activity (TOF of 446 h−1) for the fixation of CO2 with propylene oxide and was reusable for up to 4 cycles without loss in activity. Graphical Abstract

This study presents the simultaneous exfoliation and modification of heterostructured copper oxide incorporated sulfur doped graphitic carbon nitride (CuO@S-doped g-C3N4) nanocomposites synthesized via chemical precipitation and pyrolysis techniques.

The metal centres of nano-ZIF-8(Zn) and nano-ZIF-67(Co) were partially exchanged with titanium centres to form bimetallic nZIF-8(Zn/Ti) (52% Ti4+) and nZIF-67(Co/Ti) (38% Ti4+) respectively, for enhanced photocatalytic performance. A morphological and structural analysis by SEM, EDS-Mapping and PXRD showed that the particle size, distribution, and the structural integrity of the Sodalite frameworks of the parent ZIFs were retained during the exchange process to form the new bimetallic Ti-ZIFs. FTIR confirmed that no additional chemical bonds were formed during the process. XPS binding energies confirmed the preservation of the Zn(II), Co(II) and Ti(IV) oxidation states, as well as the Ti-content, consistent with ICP-OES and EDS measurements. The Ti-exchanged ZIFs showed higher activity during the photocatalytic oxidation of hydroquinone in comparison with their parent ZIFs. Their kinetic rates were nearly five times faster than those of the parent ZIFs, with the first-order rate constants k = 0.189 min-1 for nZIF-8(Zn/Ti) and k = 0.139 min-1 for nZIF-67(Co/Ti). These catalysts are efficient, stable, and reusable for three photocatalytic cycles without a significant loss of catalytic activity.

Metal–organic frameworks (MOFs) are a class of materials that are increasingly used for the detection and separation of gases. This article presents the influence of gamma radiation on the dielectric properties of a LDPE/ZIF-8 composite that can be used for the production of gas sensors and massive gas absorbers. A low-density polyethylene (LDPE)–microsized zeolitic imidazolate framework-8 (ZIF-8) composite, obtained by melt mixing (95/5 weight ratio), was gamma-irradiated at room temperature to different absorbed doses up to 300 kGy. Infrared spectroscopy and optical microscopy confirmed the degradation of the ZIF-8 due to the gamma irradiation. The AC conductivity (admittance) of the samples was studied in the frequency range of 24 Hz − 120 kHz and a temperature range 200–350 K. The composite showed larger admittance components relative to the admittance components of pure LDPE; the conductance of the samples increased almost linearly with increasing irradiation dose. On the other hand, the change in dielectric permittivity of the LDPE and the composite due to irradiation was weak and showed nonlinear behavior with increasing radiation dose.

The water-soluble ionic gold(I) complex [Au(PPh(2)CH(2)CH(2)PPh(2))(2)]Cl possesses at least ten times stronger antineoplastic activity than the water-soluble neutral silver(I) carboxylates [AgO(2)C(CH(2)OCH(2))(n)H], 1, (n=1), 2 (n=2), or 3 (n=3) even though Au(I) and Ag(I) are isoelectronic d(10) metals lying one above the other in the periodic table of the elements. In this study we determined the cytotoxicity of the stable water-soluble gold(I) carboxylates [(Ph(3)P)AuO(2)C(CH(2)OCH(2))(n)H], 4 (n=1), 5 (n=2) and 6 (n=3) to compare the intrinsic antineoplastic activity of gold(I) and silver(I) under conditions where different complex charges do not influence the result.The cytotoxicity of carboxylato gold complexes 4-6 towards the HeLa (human cervix epithelioid) cancer cell line ATCC CCL-2, resting lymphocytes and phytohaemagglutinin(PHA)-stimulated lymphocytes were determined. Cell survival was measured by means of the colorimetric 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide (MTT) assay.The IC(50) values of 4-6 from six experiments causing 50% cell growth inhibition were essentially constant; values ranged between 0.50 and 0.82 μmol dm(-3). Drug activity was thus independent of the carboxylato ligand chain length. Metal complexes 4-6 were at least one order of magnitude more cytotoxic towards the HeLa cancer cell line than the silver carboxylates 1-3 and were almost as cytotoxic as [Au(PPh(2)CH(2)CH(2)PPh(2))(2)]Cl and cisplatin [(H(3)N)(2)PtCl(2)]. Complexes 4-6 were also 2-5 times more toxic against PHA-stimulated lymphocyte cultures than to HeLa cancer cell.Unlike for the silver complexes 1-3, no meaningful drug activity-structural relationship exists for the gold(I) d(10) carboxylates 4-6. Gold(I) complexes in neutral and charged form are intrinsically more cytotoxic than silver(I) against the HeLa cancer cell line.