نتایج جستجو برای: axial and equatorial position
تعداد نتایج: 16855566 فیلتر نتایج به سال:
The conformational behaviors of 2,3-bis(methylthio)-1,4-dioxane (1), 2,3-bis(methylthio)-1,4-dithiane (2) and 2,3-bis(methylthio)-1,4-diselenane (3) have been analyzed by means ofhybrid-density functional theory (B3LYP/Def2-TZVPP) based method and NBO interpretation.B3LYP/Def2-TZVPP results showed that the axial conformations of compounds 1-3 are morestable than their equatorial conformations. ...
NBO analysis, hybrid density functional theory (B3LYP/6-311+G**) and ab initio molecular orbital (HF/6-311+G**) based methods were used to study the anomeric effects (AE), electrostatic interactions, dipole-dipole interactions and steric repulsion effects on the conformational properties of 2-methoxy- (1), 2-methylthio- (2), 2-methylseleno- (3), 2-fluoro- (4), 2-chloro- (5) and 2-bromocyclohexa...
In the title compound, C23H25ClO4, the cyclo-hexane ring adopts a chair conformation with the 4-meth-oxy-phenyl substituent in an axial position and the chloro-(4-meth-oxy-phen-yl)methyl substituent in an equatorial position. The packing features inversion dimers formed by pairs of C-H⋯O contacts and strands along [100] and [010] established by further C-H⋯O and C-H⋯Cl contacts, respectively.
The electronic structure of some idealized PH5 geometries of D3h, C4v, and C, symmetries is analyzed. Each geometry is characterized by a low-lying nodeless orbital, three singly noded orbitals close in energy, and a high-lying doubly noded nonbonding orbital. The latter orbital is the only one significantly stabilized by the inclusion of 3d orbitals in the P basis set and also determines the r...
The six-membered thio-pyran ring in the title compound, C(26)H(24)S, adopts a boat conformation, with the S atom displaced by 0.478 (2) Å and the 3-methyl-ene C atom by 0.644 (2) Å from the plane of the other four sp(2)-hydridized C atoms. The methyl group on the methyl-ene carbon lies in a pseudo-equatorial position and the phenyl ring in a pseudo-axial position.
The six-membered thio-pyran ring in the title compound, C(24)H(19)BrS, adopts an approximate envelope conformation, with the S atom displaced by 0.26 (1) Å and the 2-methyl-ene C atom by -0.54 (1) Å from the plane of the other four sp(2)-hydridized C atoms. The methyl substituent on the methyl-ene carbon lies in a pseudo-axial position with the phenyl ring in a pseudo-equatorial position.
In the title compound, C(19)H(24)O(4), the six-membered lactone ring adopts an envelope conformation with the tert-butoxy-carbonyl and isopropyl substituents in axial positions, and the phenyl group in an equatorial position. In the crystal structure, weak inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers.
nbo analysis and density functional theory (dft: b3lyp/6-311+g**) based method were used to study the impacts of the anomeric effects (ae) on the conformational properties of 2-methoxy-1,2,4,5-tetrahydro-benzo[d]oxepine (1), -thiepine (2) and -selenepine (3). the gibbs free energy difference (geq–gax) values (i.e. δgeq-ax) at 298.15 k and 1 atm between the axial and equatorial conformations inc...
In the title compound, [Cu(C(7)H(4)N(3)O(2))(2)(C(3)H(7)NO)], the Cu(II) atom is five-coordinated in a distorted square-pyramidal geometry, with the N atoms in equatorial positions and the dimethyl-formamide O atom in an axial position. The dihedral angle between adjacent benzene rings is 70.33 (12)°.
The addition of an aqueous solution diketopiperazine cyclo(Pro-Xxx) (Xxx: amino acid residue) to (?)-epigallocatechin-3-O-gallate (EGCg) led precipitation the complex EGCg and cyclo(Pro-Xxx). molecular capture abilities using were evaluated by ratio amount included in precipitates with that total used. Stronger hydrophobicity side chain residue a higher ability. Furthermore, ability decreased w...
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