Synthesis and crystal structures of 2,3,12,13-tetraalkoxy-21,23-dithiaporphyrins and 2,3-dialkoxy-21-monothiaporphyrins

Performance enhancement of a dye-sensitized solar cell by peripheral aromatic and heteroaromatic functionalization in di-branched organic sensitizers

Suppression of back reaction and enhanced photoinduced intramolecular electron transfer through peripheral functionalization of triphenylamino based dibranched donor–acceptor dyes.

Tuning Thiophene-Based Phenothiazines for Stable Photocatalytic Hydrogen Production

Dibranched donor-(π-acceptor)2 dyes, where phenothiazine is the donor core, cyanoacrylic acid is the acceptor/anchoring group, and π is represented by mono- and poly-cyclic simple and fused thiophene derivatives, were tested as photosensitizers in the photocatalytic production of H2 , in combination with a Pt/TiO2 catalyst. The optical and electrochemical properties of the dyes were investigated, showing that careful design of the thiophene-based π spacer afforded enhanced optical properties. In the H2 production over 20 h, the new thiophene-based sensitizers revealed improved stability after longer irradiation times and enhanced performances, in terms of H2 production rates and light-to-fuel efficiencies, after an initial activation period, which were for the first time associated with enhanced stability under photocatalytic production of H2 and the absence of critical dye degradation.

Colorimetric “naked eye” detection of CN−, F−, CH3COO−and H2PO4−ions by highly nonplanar electron deficient perhaloporphyrins

Highly nonplanar electron deficient perhaloporphyrins were utilized for the detection of basic anions such as CN⁻, F⁻, CH₃COO⁻and H₂PO₄⁻viaanion induced deprotonation. These sensors can be reusable without loss of their sensing ability.

Polyacryloyl hydrazide: an efficient, simple, and cost effective precursor to a range of functional materials through hydrazide based click reactions

Preparation and studies of ion exchangeable epoxy resins, stimuli responsive hydrogels, and polymer-dye conjugates have been accomplished through hydrazide based click reactions using polyacryloyl hydrazide (PAH) as the precursor. A convenient synthesis of PAH with quantitative functionality was achieved by treatment of polymethyl acrylate with hydrazine hydrate in the presence of tetra-n-butyl ammonium bromide. PAH was cured with bisphenol A diglycidyl ether (BADGE) at 60 °C to form transparent resins with superior mechanical properties (tensile strength = 2-40 MPa, Young's modulus = 3.3-1043 MPa, and ultimate elongation = 9-75%) compared to the conventional resins prepared using triethylene tetramine. The resins exhibited higher ion exchange capacities (1.2-6.3 mmol/g) compared to the commercial AHA ammonium-type (Tokuyama Co., Japan) membranes. An azo dye with aldehyde functionality was covalently attached to PAH through hydrazone linkage, and the dye labeled PAH exhibited colorimetric sensing ability for base and acids up to micromolar concentration. The swelling of the PAH based hydrogel varied in the range 4-450% depending on the pH and temperature of the medium. The hydrogels gradually released 30% of the original encapsulated dye in a period of 200 h. PAH-hydroxy naphthaldehyde conjugate released 75% of the original loading in ∼11 days at 37 °C and pH 5.0 through cleavage of the -CONHN═C- linkage. The study depicts the versatility of PAH as a precursor and inspires synthesis of a range of new materials based on PAH in the future.

Polyacryloyl hydrazide based injectable & stimuli responsive hydrogels with tunable properties

The synthesis and characterization of a series of injectable and stimuli responsive hydrogels based on polyacryloyl hydrazide have been accomplished using dimethyl 2,2′-thiodiacetate, acrylic acid, diethyl malonate and polyethylene glycol diacrylate as cross-linkers through a chemical or dual cross-linking pathway.