The laccase-catalysed oxidative coupling of substituted aromatic amines is described, extending the scope of laccases towards the production of phenazine and phenoxazinone derivatives.

Three novel bioactive silver-organic networks, namely, the 2D polymer [Ag(μ3-PTA)(chc)]n·n(Hchc)·2nH2O (1), the 3D bioMOF [Ag2(μ3-PTA)2(μ2-chdc)]n·5nH2O (2), and the 2D polymer [Ag2(μ2-PTA)2(μ4-H2chtc)]n·6nH2O (3), were constructed from 1,3,5-triaza-7-phosphaadamantane (PTA) and various flexible cyclohexanecarboxylic acids as building blocks {cyclohexanecarboxylic (Hchc), 1,4-cyclohexanedicarboxylic (H2chdc), and 1,2,4,5-cyclohexanetetracarboxylic (H4chtc) acid, respectively}. The obtained products 1-3 were fully characterized by IR and NMR spectroscopy, ESI-MS(±) spectrometry, elemental and thermogravimetric (TGA) analyses, and single-crystal and powder X-ray diffraction. Their structural diversity originates from distinct coordination modes of cyclohexanecarboxylate moieties as well as from the presence of unconventional N,N,P-tridentate or N,P-bidentate PTA spacers. Topological classification of underlying metal-organic networks was performed, disclosing the hcb, 4,4L28, and a rare fsc-3,4-Pbcn-3 topology in 1, 2, and 3, respectively. Moreover, combination of aqueous solubility (S25°C ≈ 4-6 mg mL(-1)), air stability, and appropriate coordination environments around silver centers favors a release of bioactive Ag(+) ions by 1-3, which thus act as potent antibacterial and antifungal agents against Gram-positive (S. aureus) and Gram-negative (E. coli and P. aeruginosa) bacteria as well as a yeast (C. albicans). The best normalized minimum inhibitory concentrations (normalized MIC) of 10-18 (for bacterial strains) or 57 nmol mL(-1) (for a yeast strain) were achieved. Detailed ESI-MS studies were performed, confirming the relative stability of 1-3 in solution and giving additional insight on the self-assembly formation of polycarboxylate Ag-PTA derivatives and their crystal growth process.

The present work describes the facile synthesis, full characterization, and architectural diversity of three new bioactive silver-organic networks, namely 1D 2), and 3D [Ag 2 (μ 4 -PTA)(μ 4 -mal)] n (3) coordination polymers, generated via a mixed-ligand strategy using PTA (1,3,5-triaza-7-phosphaadamantane) as a main building block and flexible aliphatic dicarboxylic acids (succinic (H 2 suc), adipic (H 2 adip), or malonic (H 2 mal) acids) as an ancillary ligand source. The compounds 1−3 were isolated as moderately air and light stable crystalline solids and were fully characterized by IR and 1 H and 31 P{ 1 H} NMR spectroscopy, elemental analysis, ESI(±)-MS spectrometry, and single-crystal X-ray crystallography. The type of aliphatic dicarboxylate plays a key role in defining the dimensionality and structural and topological features of the resulting networks, which are also driven by the PTA blocks that adopt unconventional N,P-or N 3 ,P-coordination modes. The topological analysis of simplified underlying nets revealed that 1 possesses uninodal 3-connected chains with the SP 1-periodic net (4,4)(0,2) topology, 2 features a uninodal 4-connected layer with the skl topology, and 3 reveals a uninodal 4-connected metal−organic framework with the dia topology. The presence of the crystallization water molecules in polymers 1 and 2 gives rise to the extension of their metal−organic structures into 3D (1) or 2D (2) H-bonded networks that disclose rather rare topologies. All of the obtained silver(I) coordination polymers feature solubility in water (S 25 °C ≈ 3−5 mg mL −1 ) and show significant antibacterial and antifungal activity against the selected strains of Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria and yeast (Candida albicans).

The future widespread production of biomass-derived fuels, chemicals, and materials requires cost-effective processing of sustainable feedstock. The use of imidazole as a solvent for biomass creates a novel approach that helps to accomplish this idea in a green fashion. This work proposes imidazole as a novel solvent for wheat straw pretreatment, which allowed the production of cellulose- and hemicellulose-rich fractions and added-value products from depolymerization of lignin. Various temperatures (110, 140, and 170 °C) and processing times (1, 2, and 4 h) of pretreatment were investigated. Both cellulose and hemicellulose recovery were highly dependent on reaction temperature. The best result for the recovery of cellulose-rich material was obtained at 170 °C for 2 h, achieving 62.4% w·w–1, whereas native wheat straw is composed by only 38.8% w·w–1 cellulose. For the same conditions, optimal results were also obtained regarding the enzymatic hydrolysis yield (99.3% w·w–1 glucan to glucose yield) in cellulose-rich material. This result was possible to be obtained due to morphological and structural changes in cellulose-rich materials accompanied by extensive delignification (up to 92%). The presence of added-value phenolic compounds in recovered imidazole was analyzed by capillary electrophoresis and HPLC-MS. Vanillin and other lignin-based products were identified. Finally, the high purity of recovered imidazole was demonstrated by 1H and 13C NMR.