Topic
Xanthene
About: Xanthene is a research topic. Over the lifetime, 2132 publications have been published within this topic receiving 34803 citations. The topic is also known as: Xanthene & dibenzo[a,e]pyran.
Papers published on a yearly basis
Papers
More filters
TL;DR: The hexa-coordinated chelate complexes of the type [Ru(CO)2Cl2(P-P)](1a,b) [where P-P = 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene(a) and [bis(2-diphensylphphosphinophenyl)ether(b)] have been synthesized by reacting the polymeric precursor [Ru[CO] 2Cl2]n with the ligands in 1:1 molar ratio RE
29 citations
TL;DR: The adsorption capacities of the crystals for the dyes were found to depend on both charge and hydrophobicity of the dye, reflecting the heterogeneous character of the lysozyme pore surface.
Abstract: Adsorption characteristics of cross-linked lysozyme crystals of different morphologies (tetragonal, orthorhombic, triclinic and monoclinic) were examined using four anionic dyes (fluorescein, eosin, erythrosin, and rose bengal), one zwitterionic dye (rhodamine B), and one cationic dye (rhodamine 6G). The adsorption isotherms were of the Langmuir type for all examined systems with the exception of rhodamine B adsorption by monoclinic crystals. The weakest adsorption was observed for the cationic dye, rhodamine B, whereas dianionic dyes, eosin, rose bengal, and erythrosin were strongly adsorbed on the protein surface. The adsorption capacities of the crystals for the dyes were found to depend on both charge and hydrophobicity of the dye, reflecting the heterogeneous character of the lysozyme pore surface. The adsorption affinity of the crystals for the dyes was a function of the dyes' hydrophobicity. Furthermore, the crystal morphology was identified as an additional factor determining capacity and affinity for dye adsorption. Differences between crystals prepared in the presence of the same precipitant were lower than between morphologies prepared with different precipitants.
29 citations
TL;DR: In this article, it was shown that at low temperatures the reac-tion with aromatic aldehydes stops at methane-bi-snaphthol derivatives and hindered aliphatical dehydes does not proceed at all.
Abstract: at low temperatures. However, we foundthat xanthene derivatives have been producedinstead. Further investigations showed that unhin-dered aliphatic aldehydes react with 2-naphthol togive xanthene derivatives. In the case of isobutyral-dehyde (2-methylpropanal) no reaction wasobserved with 2-naphthol. Preparation of alkyl oraryl derivatives of xanthene at relatively high tem-peratures shows that these are thermodynamicallystable compounds. The main question, whichremains, is that why at low temperatures the reac-tion with aromatic aldehydes stops at methanebi-snaphthol derivatives and hindered aliphaticaldehydes does not proceed at all. Probably, stabil-ity of the carbocation and the bulkiness of the alde-hydes are two key factors governing the reactionfate. In the case of aromatic aldehydes the carboca-tion is very stable and has the opportunity to reactwith another molecule of 2-naphthol, but its Rgroup is too bulky to permit the dehydration step toproceed. The carbocation formed from an aldehydesuch as 2-methylpropanal suffers from both itsmuch less stability and the bulkiness of R.CALCULATIONSTo have some idea of molecular shapes, wereverted to semi-empirical calculations. Molecularorbital calculations were performed by MMX-forcefield implemented in PCMODEL, and AMl calcu-lations were run using MOPAC6.0 program.
29 citations
TL;DR: It was observed that the halogen substituents increased the hydrophilicity and photodynamic activity, consistent with the cytotoxic experiments, and the lowest dipole moment and highest molecular volume of RB corroborate with its highest hydrophobicity due to heavy atom substituent like halogens, while the halogens did not affect expressively the electronic features at all.
Abstract: The aim of this study is to assess the insights of molecular properties of the xanthene dyes [fluorescein (FL), Rose Bengal (RB), erythrosin B (EB), and eosin Y (EY)] to correlate systematically their photodynamic efficiency as well as their phototoxicity against a carcinoma cell line. The phototoxicity was evaluated by comparing the values of the medium inhibitory concentration (IC50) upon HEp-2 cells with the xanthene corresponding photodynamic activity using the uric acid as a chemical dosimeter and their octanol-water partition coefficient (). RB was the more cytotoxic dye against HEp-2 cell line and the most efficient photosensitizer in causing photoxidation of uric acid; nevertheless it was the only one characterized as being hydrophobic among the xanthenes studied here. On the other hand, it was observed that the halogen substituents increased the hydrophilicity and photodynamic activity, consistent with the cytotoxic experiments. Furthermore, the reactivity index parameters, electric dipole moment, molecular volume, and the frontier orbitals were also obtained by the Density Functional Theory (DFT). The lowest dipole moment and highest molecular volume of RB corroborate with its highest hydrophobicity due to heavy atom substituents like halogens, while the halogen substituents did not affect expressively the electronic features at all.
28 citations
TL;DR: In this paper, high-soluble fluorescent fluorescein and rhodamine dyes were synthesized through amidification of their carboxylic acid functionality with original di- or tri-sulfonated amino linkers derived from taurine or α-Sulfo-β-alanine.
28 citations