نتایج جستجو برای: double bond
تعداد نتایج: 306165 فیلتر نتایج به سال:
In the title salt, C6H14NO(+)·C2H5SO4 (-), the C-N bond lengths in the cation are 1.2981 (14), 1.4658 (14) and 1.4707 (15) Å, indicating double- and single-bond character, respectively. The C-O bond length of 1.3157 (13) Å shows double-bond character, indicating charge delocalization within the NCO plane of the iminium ion. In the crystal, C-H⋯O hydrogen bonds between H atoms of the cations and...
The syntheses and structures of copper(i) chalcogenone complexes are described. The homoleptic mononuclear copper(i) complexes [(IPr[double bond, length as m-dash]E)2Cu]ClO4, IPr[double bond, length as m-dash]E, 1,3-bis(2,6-diisopropylphenyl)imidazoline-2-thione (1) and 1,3-bis(2,6-diisopropylphenyl)imidazoline-2-selone (2); [(IMes[double bond, length as m-dash]E)2Cu]ClO4, IMes[double bond, len...
The mol-ecular conformation of the title compound, C(18)H(18)O(5), is stabilized by a strong intra-molecular hydrogen bond between the hydroxyl and carbonyl groups. The C=C double bond displays an E configuration while the carbonyl group shows an S-cis configuration relative to the double bond. The dihedral angle between the two rings is 15.0 (1)°.
Double bond locations in fatty acids can be determined from characteristic charge-remote fragmentation patterns of alkali metal-adducted fatty acids following high energy collision activated dissociation (CAD). With low energy CAD, several chemical derivatization methods, including ozonization, epoxidation, and hydroxylation, have been used to generate characteristic fragments. However, high en...
BACKGROUND Bond strength of adhesive layer can absorb unwanted stresses of polymerization shrinkage in composite resin restorations; increased microshear bond strength can prevent failure of restoration materials, the purpose of this study was to evaluate the effect of adhesive layers on microshear bond strength of nanocomposite resin to dentin. MATERIAL AND METHODS Two different types of adh...
Electrostatic (through-space) and covalent (through-bond) contributions to couplings involving the C[double bond]O and C[bond]N vibrational stretching modes of the amide group in the alpha-helix and the parallel and antiparallel beta-sheet structures of alanine polypeptides are analyzed. Coupling constants computed at the density functional theory level are compared with the transition dipole c...
The Schiff base mol-ecule of the title compound, C(15)H(14)N(2)O(4)·C(3)H(7)NO, adopts a trans configuration with respect to the C=N double bond; the Schiff base itself is nearly planar (r.m.s. deviation 0.20 Å). The amido N atom is a hydrogen-bond donor to the dimethyl-formamide solvate mol-ecule. One of the hydr-oxy groups forms an intra-molecular hydrogen bond to the N atom of the C=N double...
The recently developed [P. Piecuch and M. Wloch, J. Chem. Phys. 123, 224105 (2005)] size-extensive left eigenstate completely renormalized (CR) coupled-cluster (CC) singles (S), doubles (D), and noniterative triples (T) approach, termed CR-CC(2,3) and abbreviated in this paper as CCL, is compared with the full configuration interaction (FCI) method for all possible types of single bond-breaking...
دست یابی به سیل ایده آل در ترمیم های کامپوزیتی یکی از مهمترین اهداف دندانپزشکی ترمیمی در سالهای اخیر بوده است. بررسی نفوذ رنگ رایج ترین شیوه مطالعه ریز نشت است. این روش از ارزیابی سه بعدی حساسیت کمتری دارد. به دلیل فقدان مطالعات ارزیابی ریزنشت کامپوزیت ها به روشfluid filtration در دندان های شیری، در این تحقیق بر آن شدیم تا میزان ریزنشت باندینگهایself etch و total etchرا در دندان های شیری به روش...
abstract the influence of cation?? and anion?? interactions on the strength and nature of n…h hydrogen bond has been investigated by quantum chemical calculations in s-triazine…3hf complex. ab initio calculations were performed at mp2/6-311++g(d,p) level of theory. the natural bond orbital (nbo) analysis and the bader’s quantum theory of atoms in molecules (aim) were also used to elucidate t...
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