Search results for "Molecule"
showing 10 items of 5162 documents
Slow Relaxation of the Magnetization in a {Co <sup>III</sup>Mn <sup>III</sup>} Heterometallic Brick-Wall Network
2021
The use of the cyanide-bearing dicobalt(III) complex (PPh 4 ) 2 [Co 2 III (m-2,5-dpp)(CN) 8 ] as a metalloligand towards [Mn(salen)(H 2 O)]ClO 4 afforded the heterobimetallic two-dimensional compound of formula [{Mn III (salen)} 2 {(m-NC) 4 Co 2 III (m-2,5-dpp)(CN) 4 }] n (1) [PPh 4 + = teraphenylphosphonium cation, 2,5-dpp = 2,5-bis(2-pyridyl)pyrazine and H 2 salen = N,N’ -ethylenebis(salicylideneimine)] whose structure has been determined by single crystal X-ray diffraction. Compound 1 exhibits a neutral brick-wall structure, where each [Co 2 III (m-2,5-dpp)(CN) 8 ] 2- unit adopts a tetrakis-monodentate bridging mode towards four {Mn III (salen)} + fragments through four of its eight cyan…
ChemInform Abstract: 4,4,4′,4′,7,7′-Hexamethyl-2,2′-spirobichroman.
2010
The title compound, C23H28O2, was obtained from the reaction of acetone with meta-cresol. The molecular structure consists of two identical subunits which are nearly perpendicular to each other. The oxygen-containing rings are not planar and the molecule is chiral. The crystal structure consists of chains of molecules of the same chirality arranged along the [010] axis.
1-Chloro-1,1-difluoro-N-(4-methoxyphenyl)-3-(pyrrolidin-2-ylidene)propan-2-imine
2000
In the title compound, C(14)H(15)ClF(2)N(2)O, the Z configuration has been confirmed. The molecular structure shows an intramolecular N-H.N hydrogen bond [H.N 2.04 (6), N.N 2.709 (6) A and N-H.N 124 (5) degrees ]. This interaction could be responsible for the Z configuration.
Effect of structural parameters on the polarizabilities of methanol clusters: a hirshfeld study
2008
The polarizabilities of fifty methanol clusters (CH3OH)n, n = 1 to 12, were calculated at the B3LYP/6-311++G** level of theory and partitioned into molecular contributions using the Hirshfeld-I method. The resulting molecular polarizabilities were found to be determined by the polarizabilities of the two parts of the molecule, the hydrophilic hydroxyl group and the hydrophobic methyl group, each exhibiting a different dependency upon the local environment. The polarizability of the hydroxyl group was found to be dependent on the number, type, and strength of the hydrogen bonds a methanol molecule makes, whereas the polarizability of the methyl groups is mostly influenced by sterical hindran…
Chemical transformations of a crystalline coordination polymer: a multi-stage solid–vapour reaction manifold
2013
In its crystal structure the one-dimensional coordination polymer [Ag4(O2C(CF2)2CF3)4(TMP)3]n (1) (TMP = 2,3,5,6-tetramethylpyrazine) adopts a zig-zag arrangement in which pairs of silver(I) centres bridged by two fluorocarboxylate ligands are linked alternately via one or two neutral TMP ligands. This material can reversibly absorb/desorb small alcohols (ROH) in single-crystal-to-single-crystal transformations, despite the lack of porosity in the crystals, to yield a related material of formula [Ag4(O2C(CF2)2CF3)4(TMP)3(ROH)2]n (1-ROH). The absorption process includes coordination of the alcohol to silver(I) centres and, in the process, insertion of the alcohol into one-quarter of the Ag–O…
Bonding Trends in Lewis Acid Adducts of S4N4 — X-Ray Structure of TeCl4×S4N4.
2006
Tetrasulfur tetranitride and tellurium tetrachloride react in dichloromethane to form a 1:1 adduct TeCl4·S4N4 (1). The crystal structure of 1 shows that TeCl4 is bonded to the S4N4 ring through a Te–N linkage. As a consequence, the transannular S···S bonds in S4N4 are broken and the molecule assumes an open, monocyclic conformation. The Te–N bond of 2.16(1) A is slightly longer than the single bond. The S–N bonds span a range of 1.55(1)–1.67(1) A. The adduct 1 was also characterized by mass spectrometry and Raman spectroscopy. The bonding and spectroscopic properties of 1 are compared by DFT calculations at the B3PW91/(RLC ECP) level of theory with those of BF3·S4N4 (2), SO3·S4N4 (3), AsF5·…
Synthesis, characterization and crystal structure of 2-dicyanomethylene-1,3-bis(ferrocenylmethyl)-1,3-diazolidine
1993
By reaction of N,N′-ethylenebis(ferrocenylmethylamine)1 with tetracyanoethylene in dichloromethane the yellow compound 2-dicyanomethylene-1,3-bis(ferrocenylmethyl)-1,3-diazolidine 2 can be isolated. The single-crystal structure of 2 has been determined. It crystallizes in the non-centrosymmetric trigonal space group P3221, a= 12.255(2), c= 13.831(7)A, Z= 3. Refinement of the atomic parameters by least-squares techniques gave a final R factor of 0.038 (R′= 0.034) for 1782 observed reflections having I > 2.5δ(I). Anomalous values of the bond distances and the vinyl carbon chemical shift in the 13C NMR spectrum of 2 are explained on the basis of a polarization due to a combination of the elect…
NMR Solution Conformation of the Proposed Recombin Like Structure D(CCGCGG)2
1997
Long repeated stretches of d(CCG) trinucleotide are the crucial mutation of gen that causes hereditary form of mental retardation (fragile X-syndrome). Moreover, the alternating (CG) dinucleotide is one of the candidates for Z-DNA conformation. Both sequences are part of the hexanucleotide d(CCGCGG)2- d(CCGCGG)2 forms different crystals depending on the crystallisation conditions. In one of these forms, the central alternating tetramer has a Z-DNA conformation, while the initial cytosine swings out and forms a Watson-Crick base-pair with the terminal guanine of a symmetry-related molecule. In this communication a detailed comparison between solid and solution spatial conformation by NMR of …
Molecular modeling of intercalation complexes of antitumor active 9-aminoacridine and a [d, e]-anellated isoquinoline derivative with base paired deo…
1996
Intercalators are molecules capable of sliding between DNA base pairs without breaking up the hydrogen bonds between the DNA bases. On the basis of molecular mechanics calculations structural, models of B-DNA tetranucleotide intercalation complexes of some cytostatic active 9-aminoacridines and of a [d, e]-anellated isoquinoline derivative are presented. The drug complexes are stabilized by energetically favouredvan der Waals interactions and by selective hydrogen bonds between the side chains of the drugs and the DNA bases. Semiempirical quantum chemistry calculations revealed that the chromophoric system of the intercalators is able to form π,π-charge-transfer interactions with the purine…
Interaction of antimutagenic 1,4-dihydropyridine AV-153-Na with DNA and DNA-damaging molecules and its impact on DNA repair activity
2017
1,4-dihydropyridines (1,4-DHP) possess important biochemical and pharmacological properties, including antioxidant and antimutagenic activities. Interaction of some 1,4-DHP with DNA was recently reported. AV-153-Na, an antimutagenic and DNA-repair-enhancing compound appeared to be able to interact with DNA by intercalation. The aim of the current study was to characterize DNA’s capacity for the binding of AV-153-Na, and using different approaches, to test intracellular distribution of the compound, to test the ability of the compound to scavenge peroxynitrite and hydroxyl radical and to assess the ability of the compound to modify the activity of DNA repair enzymes. The DNA binding activity…