2,4-Dimethyl-1,3-thiazole-5-carboxylic acid: an X-ray structural study at 100 K and Hirshfeld surface analysis.

The crystal structure of the title thiazolecarboxylic acid derivative, C(6)H(7)NO(2)S, (I), has been determined from single-crystal X-ray analysis at 100 K. In the crystal packing, an interplay of O-H···N and C-H···O hydrogen bonds connects the molecules to form C(6)R(2)(2)(8) polymeric chains, which are further linked via weak C-H···O hydrogen bonds into a two-dimensional supramolecular framework. The relative contributions of different interactions to the Hirshfeld surface in (I) and a few related thiazolecarboxylic acid derivatives indicate that the H···H, N···H and O···H contacts can account for about 50-70% of the total Hirshfeld surface area in this class of compound.

Synthesis of selenoxo peptides and oligoselenoxo peptides employing LiAlHSeH.

Synthesis of selenoxo peptides by the treatment of N(α)-protected peptide esters with a combination of PCl(5) and LiAlHSeH is delineated. The method is simple, high-yielding, and free from racemization. Thus obtained selenoxo peptides are used as units for N-terminal chain extension through N(α)-deprotection/coupling to yield peptide-selenoxo peptide hybrids.

A new half-condensed Schiff base compound: highly selective and sensitive pH-responsive fluorescent sensor.

A new probe, 3-[(3-benzyloxypyridin-2-ylimino)methyl]-2-hydroxy-5-methylbenzaldehyde (1-H) behaves as a highly selective fluorescent pH sensor in a Britton-Robinson buffer at 25 °C. The pH titrations show a 250-fold increase in fluorescence intensity within the pH range of 4.2 to 8.

Molecular dynamics study and electronic structure evolution of a DNA duplex d(CCCGATCGGG)2.

The molecular dynamics simulations and electronic structure evolution of a A-DNA decamer, d(CCCGATCGGG)(2), in the presence and absence of [Co(NH(3))(6)](3+) ions have been investigated. In both cases, the results of 2.5 ns MD simulation indicate a A-DNA→B-DNA transition.

A highly selective fluorescent chemosensor for zinc ion and imaging application in living cells.

A new 2,6-bis(5,6-dihydrobenzo[4,5]imidazo[1,2-c]quinazolin-6-yl)-4-methylphenol (1) serves as a highly selective and sensitive fluorescent probe for Zn(2+) in a HEPES buffer (50 mM, DMSO:water = 1:9 (v/v), pH = 7.2) at 25 °C. The increase in fluorescence in the presence of Zn(2+) is accounted for by the formation of dinuclear Zn(2+) complex [Zn(2)(C(35)H(25)N(6)O)(OH)(NO(3))(2)(H(2)O)] (2), characterized by X-ray crystallography.

4-(3,5-Dimethyl-1H-pyrazol-4-ylmethyl)-3,5-dimethyl-1H-pyrazol-2-ium dihydrogen phosphate: a combined X-ray and DFT study.

The molecular structure of the title salt, C(11)H(17)N(4)(+).H(2)PO(4)(-), has been determined from single-crystal X-ray analysis and compared with the structure calculated by density functional theory (DFT) at the BLYP level. The crystal packing in the title compound is stabilized primarily by intermolecular N-H.

2,2'-Diazinodimethylidyne)di-o-phenyl-ene) dibenzoate.

The title compound, C(28)H(20)N(2)O(4), was synthesized by the reaction of 2-(hydrazonometh-yl)phenyl benzoate with iodine. The mol-ecule possesses a crystallographically imposed center of symmetry at the mid-point of the hydrazine N-N bond. The substituents at the ends of the C=N bonds adopt an E,E configuration.

Dimethyl 6-methoxy-4abeta-methyl-9-oxo-1,2,3,4,4a,9,10,10abeta-octahydrophenanthrene-1,1-dicarboxylate.

In the title tricyclic keto-diester, C(20)H(24)O(6), a potential intermediate in the synthesis of bioactive podocarpic acid, the outer cyclohexane ring (in a chair conformation) is cis fused to the central cyclohexanone ring (in a half-chair conformation). The conformational analysis of the compound, investigated by semi-empirical quantum mechanical AM1 calculations, shows a good agreement with the X-ray structure, except for the orientation of the methyl, methoxyphenyl and methoxycarbonyl substituents.

(1SR,2RS,5RS,6SR,8RS)-7,7-Dimethyltricyclo[6.2.1.0(1,6)]undecane-2,5,6-triol: a supramolecular framework built from O-H...O hydrogen bonds.

In the title compound, C(13)H(22)O(3), the asymmetric unit has two independent molecules linked by a strong O-H...