The reaction of CoX2 (X = Cl, Br, NO3) with KTp(Ph2) in tetrahydrofuran (THF) yields the half-sandwich compounds [Tp(Ph2)CoX] (X = Cl 1, Br 2, NO3 3). The reaction of [Tp(Ph2)CoBr] with NaX (X = N3, NO2) or potassium thiocyanate (KNCS) permits isolation of [Tp(Ph2)CoX] (X = N3 4, NCS 5, NO2 6). In contrast, the reaction of cobalt(II) acetate with KTp(Ph2) yields [Tp(Ph2)CO(OAc)(Hpz(Ph2))] 7 as a result of B-N bond cleavage. Subsequent reaction of 7 with a range of beta-diketones in the presence of NaOMe produces the beta-diketonate complexes, [Tp(Ph2)Co(beta-diketonate)] (beta-diketonate = acac 8, hfac 9, dbm 10, tmhd 11). IR spectroscopy suggests that the Tp(Ph2) ligands are kappa3-coordinated and that the beta3-diketonate ligands adopt a bidentate coordination mode. Electronic spectra are consistent with four- or five-coordinate species in solution. X-Ray crystallographic studies of 7 reveal an intermediate five-coordinate cobalt centre with a hydrogen bonding interaction between the pyrazole hydrogen and the acetate carbonyl oxygen. The molecular structures of 9 and 10 show cobalt centres with square pyramidal coordination geometries and kappa2-coordinated beta-diketonate ligands. Cyclic voltammetric studies of 6 reveal irreversible one-electron reduction to Co(I). However, the beta-diketonate complexes, 8, 10 and 11 undergo irreversible one-electron oxidation. The redox potential and reversibility increases as the steric bulk of the substituent on the beta-diketonate ligand increases.

An anion-controlled synthesis of a new three-dimensional (3D) “racemate”, an enantiomorphic twofold interpenetrated 3D zinc­(II) coordination polymer containing bridging glutarate (glu) and 4,4′-bipyridine (4,4′-bipy) ligands, {[Zn4(H2O)2(4,4′-bipy)4(glu)3]­(NO3)2} n , 1 (P21/c), with ligand substitution-induced single-crystal-to-single-crystal (SCSC) transformation and photocatalysis for dye degradation was studied. The influence of a counteranion in zinc­(II) starting materials and synthetic techniques upon the phase formation were explored. The complex 1 was successfully synthesized from zinc­(II) nitrate salt via microwave-assisted techniques as well as the conventional hydrothermal technique, whereas the employment of zinc­(II) acetate or sulfate salt yielded a two-dimensional coordination polymer, [Zn­(4,4′-bipy)­(glu)] n , 2 (P1̅), and the use of zinc­(II) chloride led to a one-dimensional (1D) zigzag chain, [Zn­(4,4′-bipy)­Cl2] n 3 (C2/c). The synthetic-method-dependent formation was illustrated as the microwave-assisted techniques and conventional hydrothermal technique enabled the formation of crystalline-phase pure 1, while the sonochemical synthesis provided mixed crystalline-phases of 1 and 2. In the structure of 1, the 4,4′-bipy ligand links dinuclear Zn­(II) building units into 1D chains along the [1̅01] direction. The glu2– ligand acts as tethering linkers expanding the structure into a cationic 3D coordination polymer that interpenetrates with its enantiomer to give a 3D solid-state “racemate”. Powder X-ray diffraction revealed that the ligand substitution-induced SCSC transformation of the twofold interpenetrated 3D framework, 1 (P21/c), which was triggered by chloride, led to a 1D zigzag chain, 3 (C2/c), whereas the bromide-triggered reaction led to a mixed crystalline phase between the isostructural 1D zigzag chain, [Zn­(4,4′-bipy)­Br2] n , 4 (C2/c), and its polymorph, [Zn­(4,4′-bipy)­Br2] n , 5 (P212121). The photocatalysis for the methyl orange degradation of 1 was studied.

Lanna painting is a unique type of painting in many temples in the Northern Thai region. Similar to most mural paintings, they usually decay over time partly due to the activity of microbes. This study aimed to investigate the microorganisms from two Lanna masterpiece paintings in two temples that differ in the numbers of visitors using both culture-dependent and -independent approaches. The microorganisms isolated from the murals were also tested for the biodeterioration activities including discoloration, acid production and calcium precipitation. Most microorganisms extracted from the paintings were able to discolor the paints, but only fungi were able to discolor, produce acids and precipitate calcium. The microorganism communities, diversity and functional prediction were also investigated using the culture-independent method. The diversity of microorganisms and functional prediction were different between the two temples. Gammaproteobacteria was the predominant group of bacteria in both temples. However, the fungal communities were different between the two temples as Aspergillus was the most abundant genus in the site with higher number of visitors [Buak Krok Luang temple (BK)]. Conversely, mural paintings at Tha Kham temple (TK) were dominated by the Neodevriesia genera. We noticed that a high number of visitors (Buak Krok Luang) was correlated with microbial contamination from humans while the microbial community at Tha Kham temple had a higher proportion of saprotrophs. These results could be applied to formulate a strategy to mitigate the amount of tourists as well as manage microorganism to slow down the biodeterioration process.

A new cationic rectangular zinc(II) metal−organic framework (MOF) containing flexible chainlike bridging glutarate (glu) and rigid rodlike 4,4′-bipyridine (4,4′-bipy) ligands with an encapsulated perchlorate counteranion, {[Zn 3 (4,4′bipy) 4 (glu) 2 ](ClO 4 ) 2 } n (1; P1̅ ), was studied. Complex 1 has been successfully synthesized from the zinc(II) perchlorate salt by using microwave-heating techniques. In the crystal structure of 1, 4,4′-bipy ligands link trinuclear octahedral Zn(II) building units into rectanglular two-dimensional sheets. The glu 2− ligands with anti−anti conformation expand the structure into a cationic rectangular 3D MOF with two crystallographically related perchlorate (ClO 4 − ) counteranions encapsulated in a rectangular {Zn 3 (4,4′-bipy) 4 (glu) 2 } 2+ structure as a template of the structure. X-ray diffraction revealed the octahedral to tetrahedral (Zn oct − Zn tet ) conversion upon a ligand-substitution-induced single-crystal to single-crystal (SCSC) transformation of the octahedral Zn oct MOF 1 (P1̅ ); triggering by chloride led to a the 1D-zigzag chain [Zn tet (4,4′-bipy)Cl 2 ] n (2; C2/c), triggering by bromide led to a mixed crystalline phase between the isostructural 1D-zigzag chain [Zn tet (4,4′-bipy)Br 2 ] n (3;C2/c) and its polymorph, [Zn tet (4,4′bipy)Br 2 ] n (4; P2 1 2 1 2 1 ), and triggering by iodide led to a 3D-framework [Zn tet (glu)] n (5; P2 1 /c). The time-dependent bromidetriggered SCSC transformation was revealed by X-ray diffraction. Photocatalysis for methyl orange degradation of 1 showed that the degradation efficiency reached 14.15% within 300 min under UV-C irradiation.

Single-component ZnO nanoparticles, synthesized by a simple synthetic method, exhibit appreciable piezo-enhanced photocatalytic activities, representing an alternative to other complex systems.