Electrochromism of dinitrobenzoyl-derivatised polypyrrole films deposited on ITO/glass electrodes

Poly[(R)-(-)-3-(1-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate] films of various thicknesses were galvanostatically deposited on ITO/glass electrodes using different deposition charges (Q_dep), and their electrochromic properties were investigated. Depending on the Q_dep employed, the polymeric films presented green-yellow or green-brown colours in the reduced state (λ_max at 350 nm and shoulder at 390 nm) and a blue-grey colour in the oxidised state (λ_max at 460 nm) with high absorption in the near infrared region (λ_max > 800 nm). Whilst films deposited with a Q_dep of 40 mC cm⁻² presented the highest chromatic contrast (20%), films with a Q_dep of 50 mC cm⁻² exhibited greater stability to redox cycling (ca. 350 cycles), high coulombic efficiency (>73%) and good optical memory in the reduced state (E = 0.0 V).     

Electrochemical polymerisation of thiophene derivative induced by Lewis acid: Electrosynthesis of poly[(R)-(−)-2-(3′-thienyl)ethyl-(3′,5″-dinitrobenzoyl)-α-phenylglycinate]

Films of poly[(R)-(−)-2-(3′-thienyl)ethyl-(3′,5″-dinitrobenzoyl)-α-phenylglycinate] were deposited on ITO electrodes by potentiodynamic, potentiostatic and galvanostatic methods using a (C₄H₉)₄NBF₄/CH₃CN electrolyte system containing 20% boron trifluoride diethyl etherate. Polymerisation occurred as a charge dependent process at a potential of 1.4 V vs. Ag/Ag⁺(CH₃CN). The surface morphologies of the films so-formed were examined using atomic force microscopy. The film deposited by the galvanostatic method displayed more homogeneous grain geometry and a larger superficial area than those formed by the other methods. Cyclic voltammetry revealed a well defined redox couple at the anodic region, attributable to polymer p-doping, and a poorly defined redox pair at the cathodic region, attributable to the reduction of the nitro group. The polymeric films obtained were yellow in colour (λ_max 425 nm) in the reduced state and light blue (λ_max 745 nm) in the oxidised state.     

取代苯基膦酸的合成

成功地合成了三个未见报道的取代苯基膦酸，并对其合成工艺进行了研讨，为噻唑偶氮膦酸型显色剂的合成提供了有关键中间体。     

Dependence of antimicrobial properties on site-selective arrangement and concentration of bioactive Cu2+ ions in tricalcium phosphate

Cu-doped solid solutions Ca_10.5–xCu_x(PO₄)₇ with β-Ca₃(PO₄)₂ (β-TCP) structure were synthesized using high-temperature solid-state synthesis. Correctly characterizing the location of Cu²⁺ in the structure is important for a correct understanding of the biological properties formation. The limit of Ca_10.5–xCu_x(PO₄)₇ solid solutions without impurity phases was found at x = 1.5. The crystal-chemical analysis reveals that the Cu²⁺ ions cannot be located in the M4 site of the β-TCP-type structure due to the very distorted environment. The Cu²⁺ ions preferably occupy the M5 site (x ≤ 1.00) and then located in the M3 and M2 sites (x > 1.00). The chemical composition, local environment, and structural features of Ca_10.5–xCu_x(PO₄)₇ phosphates were investigated by a complex of methods. The antibacterial properties were studied on one fungus (C. albicans) and four bacteria (E. coli, E. faecalis S. aureus and P. aeruginosa). Biocompatibility tests were performed on human bone marrow mesenchymal stem cells (hMSCs). The biological response of the Cu²⁺ strongly depends on the occupied ion position and its concentration. The concentration-dependent behavior of the bacteria growth inhibition was observed, and the sample with x = 1.33 exhibits the highest activity between single-phase samples. Further increasing of bacteria growth inhibition is attributed to Ca₃Cu₃(PO₄)₄ impurity phase. Also, antimicrobial properties depend on the Cu²⁺ location in the β-TCP crystal structure in accordance with ion release behavior. The Cu²⁺ location in the large M3 polyhedra leads to a noticeable increase in ion release. Biocompatibility assays on hMSCs showed the absence of cytotoxicity in direct and indirect contact for single-phase samples. In the biphasic sample the presence of impurity Ca₃Cu₃(PO₄)₄ phosphate at 2 wt% causes a cytotoxicity effect. Thus, phase purity plays a critical role in understanding the regularities of bioactive properties formation. This work can be an initial basis for further investigations of the site-selective arrangement of bioactive ions, such as Cu²⁺ and other similar ions, in the β-TCP structure to enhance biological potential.