- Ferrocene amphiphilic D-π-A dyes: Synthesis, redox behavior and determination of band gaps
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We report the synthesis of a series of ferrocene amphiphilic donor-π-acceptor dyes, with the general formula (Fc-CHCH-HetNC16H33)+ X- [where: Fc behaves as the donor group, a double bond as the π bridge, and 2-,4-pyridinium and 4-quinolinium as the potent acceptor groups (2a-b and 4, X = Br- or BF4-)], in good overall yields. Together with their neutral counterparts (6a-b and 7), the photophysical and electrochemical properties of these compounds were investigated by means of UV-Vis spectroscopy and cyclic voltammetry. The optical and electrochemical band gaps of these dyes were calculated, which indicated that 4 has the lowest bandgap value. Time-dependent DFT calculations indicate that the lowest energy absorption band displayed for these compounds has mainly metal-to-ligand charge transfer character, with the HOMO-LUMO electronic transition being the main contribution.
- López-Mayorga,Sandoval-Chávez,Carreón-Castro,Ugalde-Saldívar,Cortés-Guzmán,López-Cortés,Ortega-Alfaro
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- β-CD assisted aqueous dissolution of cetylpicolinium dichromates (CPDC)—Evolution of a class of green water compatible lipopathic Cr(VI) oxidants
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Water-insoluble lipopathic dichromates have been successfully solubilized in aqueous phase by the entrapment of their hydrophobic tails in β-cyclodextrin (β-CD) non-polar cavity. Aqueous solubility of α-, β-, and γ- cetylpicolinium dichromate (CPDC) molecules, synthesized in our lab, has been studied to find their suitability for Cr(VI) oxidation purposes in water medium. The analysis of phase solubility shows the existence of a Bs type curve and its significance has been fully deciphered through dynamic light scattering (DLS) analysis. The limiting concentration of β-CD up to which it can induce 1:1 host-guest complexation with the CPDC entities, has been determined and the stoichiometry has been confirmed from Job's plot. The binding constant and complexation efficiency of the β-CD-CPDC complexes have been determined and temperature effect on these parameters has been discussed through thermodynamic calculations. Analyses of viscosity variation of the aqueous solutions of the complexes have been done and correlated with the solubilization phenomenon.
- Priyadarshini, Supriya,Guru, Partha Sarathi,Dash, Sukalyan
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- Wide-Antimicrobial Spectrum of Picolinium Salts
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Nosocomial infections, which greatly increase morbidity among hospitalized patients, together with growing antibiotic resistance still encourage many researchers to search for novel antimicrobial compounds. Picolinium salts with different lengths of alkyl chains (C12, C14, C16) were prepared by Menshutkin-like reaction and evaluated with respect to their biological activity, i.e., lipophilicity and critical micellar concentration. Picolinium salts with C14 and C16 side chains achieved similar or even better results when in terms of antimicrobial efficacy than benzalkoniums; notably, their fungicidal efficiency was substantially more potent. The position of the methyl substituent on the aromatic ring does not seem to affect antimicrobial activity, in contrast to the effect of length of the N-alkyl chain. Concurrently, picolinium salts exhibited satisfactory low cytotoxicity against mammalian cells, i.e., lower than that of benzalkonium compounds, which are considered as safe.
- Benkova, Marketa,Dolezal, Rafael,Gunde-Cimerman, Nina,Kuca, Kamil,Malinak, David,Marek, Jan,Prchal, Lukas,Salajkova, Sarka,Sep?íc, Kristina,Sleha, Radek,Soukup, Ondrej
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