نتایج جستجو برای: type ii halogenhalogen contacts are halogen bonds
تعداد نتایج: 6157948 فیلتر نتایج به سال:
Six novel halogen-bonded cocrystals of 1,3,5-triiodo-2,4,6-trifluorobenzene with three structural isomers benzoylpyridine have been synthesized mechanochemically and by crystallization from solution, five which were structurally characterized. In four cocrystals, is a ditopic halogen-bond acceptor participating in halogen bonding both pyridine nitrogen carbonyl oxygen atoms, while one cocrystal...
We report a new spectroscopic fingerprint of intermolecular contacts in halogen bond-driven self-assembling aggregates and a precise determination of intermolecular NI distances in microcrystalline samples.
The mol-ecular structure of the title compound, C7H10Br2O4, confirms the meso (2R,6S) configuration. In the crystal, mol-ecules are linked by pairs of O-H⋯O=C hydrogen bonds between their terminal carboxyl groups in an R 2 (2)(8) motif, forming extended chains that propagate parallel to the c axis. Adjacent chains are linked by C=O⋯Br halogen bonds.
The chelate effect of a tridentate receptor is exploited to determine halogen bonding association constants that vary by several orders of magnitude, including interactions of weak donors for which thermodynamic data were not previously available. Free energy relationships with computed and experimental properties hold over this wide range of donors. The strengths of iodine- and bromine-based h...
DFT calculations reveal that halogen bonds and 3c-4e make a difference in the metal-iodylarene chemistry.
Chiral phase transitions were studied in a self-assembled 2,6-dibromoanthraquinones supramolecular system prepared on Au(111) using scanning tunneling microscopy. As the molecules were deposited at about 150 K, they formed heterochiral chevron structures (a racemate) consisting of two alternating prochiral molecular rows. When the as-deposited sample was warmed to 300 K followed by cooling to 8...
The nature of halogen bonding in 128 complexes was investigated using advanced quantum mechanical calculations. First, isolated halogen donors were studied and their σ-holes were described in terms of size and magnitude. Later, both partners in the complex were considered and their interaction was described in terms of DFT-SAPT decomposition. The whole set of complexes under study was split int...
Infinite chains connected by N-H...N hydrogen bonding form the primary packing motif in two closely related 4-nitroimidazole derivatives, viz. 5-bromo-2-methyl-4-nitro-1H-imidazole, C(4)H(4)BrN(3)O(2), (I), and 2-methyl-4-nitro-1H-imidazole-5-carbonitrile, C(5)H(4)N(4)O(2), (II). These chains are almost identical, even though in (II) there are two symmetry-independent molecules in the asymmetri...
Results from ab initio electronic structure theory calculations on model systems allow for the detailed comparison of tunneling through covalently bonded contacts, hydrogen bonds, and van der Waals contacts. Considerable geometrical sensitivity as well as an exponential distance dependence of the tunneling is observed for tunneling through various nonbonded contacts. However, the fundamental re...
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