Novel organically linked ZnII hydrogenselenite coordination polymers: synthesis, characterization, and efficient TiO2 photosensitization for enhanced photocatalytic hydrogen production.

This study focused on the solvothermal synthesis, characterization, and photocatalytic activities of two novel coordination polymers, namely [Zn(µ-HSeO3)2(bipy)]n (1) and [Zn(µ-HSeO3)2(phen)]n (2). These compounds represent the first organically linked ZnII hydrogenselenite coordination polymers. The synthesis of compounds 1 and 2 involved the addition of 2,2'-bipyridine and 1,10-phenanthroline, respectively, to SeO2 and ZnO in methanol as the solvent. The novel hydrogenselenite compounds were thoroughly characterized using spectroscopic and crystallographic methods. The photocatalytic solids (TiO2-1A and TiO2-2A) were prepared by immobilizing compounds 1-2 onto TiO2 through the sol-gel approach. These photocatalysts were then evaluated for hydrogen evolution via water splitting using a 300 W Hg/Xe lamp as the irradiation source. Among the newly synthesized photocatalytic materials, TiO2-1A demonstrated auspicious photocatalytic performance for hydrogen gas production. Its catalytic activity overcame the observed for the pure solid support TiO2 and Degussa P25 (commercial titania), making compound 1 a particularly attractive TiO2 photosensitizer. Additionally, TiO2-1A exhibited superior photocatalytic activity compared to TiO2-2A. The latter performed better than freshly prepared TiO2, approaching that of Degussa P25. These findings highlight the potential of compound 1 as an effective photosensitizer for TiO2-based photocatalysis, making it a promising candidate for applications in clean energy generation, specifically in hydrogen production by water splitting.

Synthesis, crystal structure and Hirshfeld analysis of trans-bis-{(2E)-N-phenyl-2-[(2E)-3-phenyl-2-propen-1-yl-idene]hydrazinecarbo-thio-amidato-κ2N1,S}palladium(II).

The reaction of (2E)-N-phenyl-2-[(2E)-3-phenyl-2-propen-1-yl-idene]hydra-zine-carbo-thio-amide (common name: cinnamaldehyde-4-phenyl-thio-semi-carbazone) deprotonated with NaOH in ethanol with an ethano-lic suspension of PdII chloride in a 2:1 molar ratio yielded the title compound, [Pd(C16H14N3S)2]. The anionic ligands act as metal chelators, κ2 N 1 S-donors, forming five-membered rings with a trans-configuration. The PdII ion is fourfold coordinated in a slightly distorted square-planar geometry. For each ligand, one H⋯S and one H⋯N intra-molecular inter-actions are observed, with S(5) and S(6) graph-set motifs. Concerning the H⋯S inter-actions, the coordination sphere resembles a hydrogen-bonded macrocyclic environment-type. In the crystal, the complexes are linked via pairs of H⋯S inter-actions, with graph-set motif R 2 2(8), and building a mono-periodic hydrogen-bonded ribbon along [001]. The Hirshfeld surface analysis indicates that the major contributions for the crystal cohesion are: H⋯H (45.3%), H⋯C/C⋯H (28.0%), H⋯S/S⋯H (8.0%) and H⋯N/N⋯H (7.4%).

2-{1-[(6R,S)-3,5,5,6,8,8-Hexamethyl-5,6,7,8-tetra-hydro-naphthalen-2-yl]ethyl-idene}-N-methyl-hydrazinecarbo-thioamide.

The reaction between a racemic mixture of (R,S)-fixolide and 4-methyl-thio-semicarbazide in ethanol with a 1:1 stoichiometric ratio and catalysed with HCl, yielded the title compound, C20H31N3S [common name: (R,S)-fixolide 4-methyl-thio-semicarbazone]. There is one crystallographically independent mol-ecule in the asymmetric unit, which is disordered over the aliphatic ring [site-occupancy ratio = 0.667 (13):0.333 (13)]. The disorder includes the chiral C atom, the neighbouring methyl-ene group and the methyl H atoms of the methyl group bonded to the chiral C atom. The maximum deviations from the mean plane through the disordered aliphatic ring amount to 0.328 (6) and -0.334 (6) Š[r.m.s.d. = 0.2061 Å], and -0.3677 (12) and 0.3380 (12) Š[r.m.s.d. = 0.2198 Å] for the two different sites. Both fragments show a half-chair conformation. Additionally, the N-N-C(=S)-N entity is approximately planar, with the maximum deviation from the mean plane through the selected atoms being 0.0135 (18) Š[r.m.s.d. = 0.0100 Å]. The mol-ecule is not planar due to the dihedral angle between the thio-semicarbazone entity and the aromatic ring, which amounts to 51.8 (1)°, and due to the sp 3-hybridized carbon atoms of the fixolide fragment. In the crystal, the mol-ecules are connected by H⋯S inter-actions with graph-set motif C(4), forming a mono-periodic hydrogen-bonded ribbon along [100]. The Hirshfeld surface analysis suggests that the major contributions for the crystal cohesion are [(R,S)-isomers considered separately] H⋯H (75.7%), H⋯S/S⋯H (11.6%), H⋯C/C⋯H (8.3% and H⋯N/N⋯H (4.4% for both of them).

Synthesis, crystal structure and Hirshfeld analysis of trans-bis-(2-{1-[(6R,S)-3,5,5,6,8,8-hexa-methyl-5,6,7,8-tetra-hydronaphthalen-2-yl]ethyl-idene}-N-methyl-hydrazinecarbo-thio-amidato-κ2N2,S)palladium(II) ethanol monosolvate.

The reaction between the (R,S)-fixolide 4-methyl-thio-semicarbazone and PdII chloride yielded the title compound, [Pd(C20H30N3S)2]·C2H6O {common name: trans-bis-[(R,S)-fixolide 4-methyl-thio-semicarbazonato-κ2 N 2 S]palladium(II) ethanol monosolvate}. The asymmetric unit of the title compound consists of one bis-thio-semicarbazonato PdII complex and one ethanol solvent mol-ecule. The thio-semicarbazononato ligands act as metal chelators with a trans configuration in a distorted square-planar geometry. A C-H⋯S intra-molecular inter-action, with graph-set motif S(6), is observed and the coordination sphere resembles a hydrogen-bonded macrocyclic environment. Additionally, one C-H⋯Pd anagostic inter-action can be suggested. Each ligand is disordered over the aliphatic ring, which adopts a half-chair conformation, and two methyl groups [s.o.f. = 0.624 (2):0.376 (2)]. The disorder includes the chiral carbon atoms and, remarkably, one ligand has the (R)-isomer with the highest s.o.f. value atoms, while the other one shows the opposite, the atoms with the highest s.o.f. value are associated with the (S)-isomer. The N-N-C(=S)-N fragments of the ligands are approximately planar, with the maximum deviations from the mean plane through the selected atoms being 0.0567 (1) and -0.0307 (8) Š(r.m.s.d. = 0.0403 and 0.0269 Å) and the dihedral angle with the respective aromatic rings amount to 46.68 (5) and 50.66 (4)°. In the crystal, the complexes are linked via pairs of N-H⋯S inter-actions, with graph-set motif R 2 2(8), into centrosymmetric dimers. The dimers are further connected by centrosymmetric pairs of ethanol mol-ecules, building mono-periodic hydrogen-bonded ribbons along [011]. The Hirshfeld surface analysis indicates that the major contributions for the crystal cohesion are [atoms with highest/lowest s.o.f.s considered separately]: H⋯H (81.6/82.0%), H⋯C/C⋯H (6.5/6.4%), H⋯N/N⋯H (5.2/5.0%) and H⋯S/S⋯H (5.0/4.9%).

Vermicomposting of cow manure: Effect of time on earthworm biomass and chemical, physical, and biological properties of vermicompost.

Vermicomposting is a biological process for efficient cattle manure treatment, but the vermicomposting time determines the quality of the vermicompost. The objective of this study was to evaluate the effect of cattle manure vermicomposting time on earthworm biomass and the changes in physical, chemical, and biological in properties of the vermicompost. The cattle manure was inoculated with Eisenia andrei earthworms and conducted vermicomposting for 0, 15, 30, 45, 60, and 120 days. The analysis of 44 chemical, physical, and biological properties allowed the vermicomposting process to be divided into initial (<45 days) and final (45-120 days) phases. The initial phase was characterized by high microbial activity and the final by high physical-chemical transformation of the vermicompost and an increase in earthworm density. The organic matter aromaticity increased until the 45th day, subsequently decreasing. Although 30 d of vermicompost are sufficient to obtain a high-quality organic fertilizer, 120 d are necessary for producing matrices.

One- and two-dimensional PbII compounds resulting from reaction of PbBr2 and Pb(SCN)2 with pyrimidine-2-thione.

Pyrimidine-2-thione (HSpym) reacts with lead(II) thiocyanate and lead(II) bromide in N,N-dimethylformamide (DMF) to form poly[(µ-isothiocyanato-κ2N:S)(µ4-pyrimidine-2-thiolato-κ6N1,S:S:S:S,N3)lead(II)], [Pb(C4H3N2S)(NCS)]n or [Pb(Spym)(NCS)]n, (I), and the polymeric one-dimensional (1D) compound catena-poly[[µ4-bromido-di-µ-bromido-(µ-pyrimidine-2-thiolato-κ3N1,S:S)(µ-pyrimidine-2-thione-κ3N1,S:S)dilead(II)] N,N-dimethylformamide monosolvate], {[Pb2Br3(C4H3N2S)(C4H4N2S)]·C3H7NO}n or {[Pb2Br3(Spym)(HSpym)]·DMF}n, (IIa), respectively. Poly[µ4-bromido-di-µ3-bromido-(µ-pyrimidine-2-thiolato-κ3N1,S:S)(µ-pyrimidine-2-thione-κ3N1,S:S)dilead(II)], [Pb2Br3(C4H3N2S)(C4H4N2S)]n or [Pb2Br3(Spym)(HSpym)]n, (IIb), could be obtained as a mixture with (IIa) when using a lesser amount of solvent. In the crystal structures of the pseudohalide/halide PbII stable compounds, coordination of anionic and neutral HSpym has been observed. Both Spym- (in the thiolate tautomeric form) and NCS- ligands were responsible for the two-dimensional (2D) arrangement in (I). The Br- ligands establish the 1D polymeric arrangement in (IIa). Eight-coordinated metal centres have been observed in both compounds, when considering the Pb...S and Pb...Br interactions. Both compounds were characterized by FT-IR and diffuse reflectance spectroscopies, as well as by powder X-ray diffraction. Compound (IIa) and its desolvated version (IIb) represent the first structurally characterized PbII compounds containing neutral HSpym and anionic Spym- ligands. After a prolonged time in solution, (IIa) is converted to another compound due to complete deprotonation of HSpym. The structural characterization of (I) and (II) suggests HSpym as a good candidate for the removal of PbII ions from solutions containing thiocyanate or bromide ions.

Synthesis, crystal structure and Hirshfeld analysis of a crystalline compound comprising a 1/1 mixture of 1-[(1R,4S)- and 1-[(1S,4R)-1,7,7-trimethyl-2-oxobi-cyclo[2.2.1]heptan-3-yl-idene]hydrazinecarbo-thio-amide.

The equimolar reaction between a racemic mixture of (R)- and (S)-camphorquinone with thio-semicarbazide yielded the title compound, C11H17N3OS [common name: (R)- and (S)-camphor thio-semicarbazone], which maintains the chirality of the methyl-ated chiral carbon atoms and crystallizes in the centrosymmetric space group C2/c. There are two mol-ecules in general positions in the asymmetric unit, one of them being the (1R)-camphor thio-semicarbazone isomer and the second the (1S)- isomer. In the crystal, the mol-ecular units are linked by C-H⋯S, N-H⋯O and N-H⋯S inter-actions, building a tape-like structure parallel to the (01) plane, generating R 2 1(7) and R 2 2(8) graph-set motifs for the H⋯S inter-actions. The Hirshfeld surface analysis indicates that the major contributions for crystal cohesion are from H⋯H (55.00%), H⋯S (22.00%), H⋯N (8.90%) and H⋯O (8.40%) inter-actions.

Neutral 4-phenyl-1-[phenyl(pyridin-2-yl)methylidene]semicarbazide and its salt forms with inorganic anions.

Semicarbazones can exist in two tautomeric forms. In the solid state, they are found in the keto form. This work presents the synthesis, structures and spectroscopic characterization (IR and NMR spectroscopy) of four such compounds, namely the neutral molecule 4-phenyl-1-[phenyl(pyridin-2-yl)methylidene]semicarbazide, C19H16N4O, (I), abbreviated as HBzPyS, and three different hydrated salts, namely the chloride dihydrate, C19H17N4O+·Cl-·2H2O, (II), the nitrate dihydrate, C19H17N4O+·NO3-·2H2O, (III), and the thiocyanate 2.5-hydrate, C19H17N4O+·SCN-·2.5H2O, (IV), of 2-[phenyl({[(phenylcarbamoyl)amino]imino})methyl]pyridinium, abbreviated as [H2BzPyS]+·X-·nH2O, with X = Cl- and n = 2 for (II), X = NO3- and n = 2 for (III), and X = SCN- and n = 2.5 for (IV), showing the influence of the anionic form in the intermolecular interactions. Water molecules and counter-ions (chloride or nitrate) are involved in the formation of a two-dimensional arrangement by the establishment of hydrogen bonds with the N-H groups of the cation, stabilizing the E isomers in the solid state. The neutral HBzPyS molecule crystallized as the E isomer due to the existence of weak π-π interactions between pairs of molecules. The calculated IR spectrum of the hydrated [H2BzPyS]+ cation is in good agreement with the experimental results.