Crystal chemistry of tetraradial species. Part 6. Embarras de richesses: lithium cation coordinated by eight O—H … phenyl bonds

1994 ◽  
Vol 72 (10) ◽  
pp. 2144-2152 ◽  
Author(s):  
Pradip K. Bakshi ◽  
Sergey V. Sereda ◽  
Osvald Knop ◽  
Michael Falk
Keyword(s):  
Hydrogen Bonds ◽  
Variable Temperature ◽  
Detailed Comparison ◽  
Lithium Cation ◽  
3 Dimensional ◽  
Essentially Normal ◽  
Free Ions ◽  
Tetrahedral Angle ◽  
Ft Ir ◽  
Packing Effects

Lithium tetraphenylborate tetrahydrate, [Li(OH2)4]BPh4 (LiTBw; tetragonal, I41/a, a = 27.566(2) Å, c = 12.228(2) Å, Z = 16) is remarkable in that the four H2O molecules coordinating the Li+ ion all form O—H …π hydrogen bonds to the phenyl groups of the anion. LiTBw thus appears to be the first reported example of such an exhaustive O—H …π coordination and can be described as a 3-dimensional, completely H-bonded polymer in which all the H2O hydrogens are bonded to phenyl groups and all the phenyl groups are involved in O—H … phenyl bonds. Six of the O—H … phenyl bonds are essentially normal and two are highly bent, possibly bifurcated. The existence of the H-bonds has been corroborated from variable-temperature FT-ir spectra of weakly deuterated LiTBw. The O—Li—O angles in the LiO4 coordination tetrahedron (of symmetry C1) exhibit large departures from the tetrahedral angle, two of the angles bisected by a quasi-S4 axis being 118.3° and 122.5°, respectively. An ab initio (6-31G*) investigation of the Li(OH2)4+ and Be(OH2)42+ cations has shown that such large O—M—O angles are to be expected even in the free ions and are thus not necessarily the result of packing effects. A detailed comparison with several Li(OH2)4+ and Be(OH2)42+ salts provides a rationale for the observed M(OH2)4n+ (M = Li, Be) geometries.

scholarly journals Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione form 2

2006 ◽  
Vol 62 (7) ◽  
pp. o3046-o3048 ◽  
Author(s):  
Ashley T Hulme ◽  
Philippe Fernandes ◽  
Alastair Florence ◽  
Andrea Johnston ◽  
Kenneth Shankland
Keyword(s):  
Crystal Structure ◽  
Simulated Annealing ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Title Compound ◽  
Variable Temperature ◽  
Polycrystalline Sample ◽  
Asymmetric Unit ◽  
X Ray ◽  
Compound C

A polycrystalline sample of a new polymorph of the title compound, C8H11NO2, was produced during a variable-temperature X-ray powder diffraction study. The crystal structure was solved at 1.67 Å resolution by simulated annealing from laboratory powder data collected at 250 K. Subsequent Rietveld refinement yielded an R wp of 0.070 to 1.54 Å resolution. The structure contains two molecules in the asymmetric unit, which form a C 2 2(8) chain motif via N—H...O hydrogen bonds.

Combined Experimental and CFD Study of a HP Blade Multi-Pass Cooling System

2009 ◽  
Author(s):  
D. Jackson ◽  
P. Ireland ◽  
B. Cheong
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Cooling System ◽  
Detailed Comparison ◽  
Bulk Temperature ◽  
Internal Cooling ◽  
3 Dimensional ◽  
Turbine Cooling ◽  
Cooling Hole ◽  
The Difference

Progress in the computing power available for CFD predictions now means that full geometry, 3 dimensional predictions are now routinely used in internal cooling system design. This paper reports recent work at Rolls-Royce which has compared the flow and htc predictions in a modern HP turbine cooling system to experiments. The triple pass cooling system includes film cooling vents and inclined ribs. The high resolution heat transfer experiments show that different cooling performance features are predicted with different levels of fidelity by the CFD. The research also revealed the sensitivity of the prediction to accurate modelling of the film cooling hole discharge coefficients and a detailed comparison of the authors’ computer predictions to data available in the literature is reported. Mixed bulk temperature is frequently used in the determination of heat transfer coefficient from experimental data. The current CFD data is used to compare the mixed bulk temperature to the duct centreline temperature. The latter is measured experimentally and the effect of the difference between mixed bulk and centreline temperature is considered in detail.

Mono- and dinuclear CuII complexes of the benzyldipicolylamine (BDPA) ligand: crystal structure, synthesis and characterization

2017 ◽  
Vol 73 (11) ◽  
pp. 1024-1029
Author(s):  
Dharmalingam Sivanesan ◽  
Min Hye Youn ◽  
Ki Tae Park ◽  
Hak Joo Kim ◽  
Andrews Nirmala Grace ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Reaction Medium ◽  
Bound Water ◽  
Dinuclear Complex ◽  
Residual Moisture ◽  
Structure Synthesis ◽  
Distorted Octahedral ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Solvent Molecules

The crystal structures of mono- and dinuclear CuII trifluoromethanesulfonate (triflate) complexes with benzyldipicolylamine (BDPA) are described. From equimolar amounts of Cu(triflate)2 and BDPA, a water-bound CuII mononuclear complex, aqua(benzyldipicolylamine-κ3 N,N′,N′′)bis(trifluoromethanesulfonato-κO)copper(II) tetrahydrofuran monosolvate, [Cu(CF3SO3)2(C19H19N3)(H2O)]·C4H8O, (I), and a triflate-bridged CuII dinuclear complex, bis(μ-trifluoromethanesulfonato-κ2 O:O′)bis[(benzyldipicolylamine-κ3 N,N′,N′′)(trifluoromethanesulfonato-κO)copper(II)], [Cu2(CF3SO3)4(C19H19N3)2], were synthesized. The presence of residual moisture in the reaction medium afforded water-bound complex (I), whereas dinuclear complex (II) was synthesized from an anhydrous reaction medium. Single-crystal X-ray structure analysis reveals that the CuII centres adopt slightly distorted octahedral geometries in both complexes. The metal-bound water molecule in (I) is involved in intermolecular O—H...O hydrogen bonds with triflate ligands and tetrahydrofuran solvent molecules. In (II), weak intermolecular C—H...F(triflate) and C—H...O(triflate) hydrogen bonds stabilize the crystal lattice. Complexes (I) and (II) were also characterized fully using FT–IR and UV–Vis spectroscopy, cyclic voltammetry and elemental analysis.

scholarly journals Syntheses, Structures, Magnetic Properties and Antibacterial Activities of Two Copper(II) Azido Complexes with Varied Nuclearities Containing Symmetrical 1,3-Diammine as Chelator

2021 ◽  
Vol 33 (2) ◽  
pp. 359-366
Author(s):  
Habibar Chowdhury ◽  
Chandan Adhikary
Keyword(s):  
Hydrogen Bonds ◽  
Variable Temperature ◽  
Antibacterial Activities ◽  
Metal Centers ◽  
X Ray ◽  
Pyramidal Geometry ◽  
Azide Ion ◽  
3D Network ◽  
Square Pyramidal Geometry ◽  
Dinuclear Structure

Two copper(II) azido complexes of the types mononuclear [Cu(TMEDA)2(N3)2] (1) and dinuclear [Cu(TMEDA)(μ1,1-N3)(N3)]2 (2) [TMEDA = trimethylenediamine; N3 – = azide ion] have been synthesized and characterized. X-ray structural analysis revealed that each copper(II) center in complex 1 adopts a distorted octahedron geometry with a CuN6 chromophore ligated through four N atoms of two different symmetrical TMEDA ligands as bidentate chelator and two N atoms of two terminal azides. In complex 2, each copper(II) center adopts a distorted square pyramidal geometry with a CuN5 chromophore ligated through two N atoms of TMEDA as bidentate chelator and two N atoms of two different azides as μ1,1-N3 bridging mode and one N atom of terminal azide ion. The two copper centers are connected through double μ1,1-N3 bridges affording a dinuclear structure with Cu···Cu separation 3.327(2) Å. In crystalline state, mononuclear units in complex 1 are associated through intermolecular N-H···N and C-H···N hydrogen bonds to form a 2D sheet structure viewed along crystallographic b-axis, whereas dinuclear entities in complex 2 are propagated through intermolecular N-H···N and C-H···N hydrogen bonds to form a 3D network structure viewed along crystallographic a-axis. The Variable-temperature magnetic susceptibility measurement evidenced a dominant antiferromagnetic interaction between the metal centers through μ1,1-azide bridges in complex 2 with J = − 0.40 cm-1. The antibacterial activities of the complexes have also been studied.

Synthesis, spectroscopic (FT–IR and UV–Vis), crystallographic and theoretical studies, and a molecular docking simulation of an imatinib-like template

2019 ◽  
Vol 75 (12) ◽  
pp. 1681-1689
Author(s):  
Rodolfo Moreno-Fuquen ◽  
Kevin Arango-Daraviña ◽  
Esteban Garcia ◽  
Juan-C. Tenorio ◽  
Javier Ellena
Keyword(s):  
Crystal Growth ◽  
Hydrogen Bonds ◽  
Docking Simulation ◽  
Myelogenous Leukemia ◽  
Amino Group ◽  
Protein Residues ◽  
Function Analyzer ◽  
Stretching Vibration ◽  
Donor Acceptor ◽  
Ft Ir

The aim of the present study was to report the crystal structure and spectroscopic, electronic, supramolecular and electrostatic properties of a new polymorph of 4-(pyridin-2-yl)pyrimidin-2-amine (C9H8N4). The compound was synthesized under microwave irradiation. The single-crystal X-ray structure analysis revealed an angle of 13.36 (8)° between the planes of the rings, as well as molecules linked by Nsp 2—H...N hydrogen bonds forming dimers along the crystal. The material was analyzed by FT–IR vibrational spectroscopy, while a computational approach was used to elucidate the vibrational frequency couplings. The existence of Nsp 2—H...N hydrogen bonds in the crystal was confirmed spectroscopically by the IR peaks from the N—H stretching vibration shifting to lower wavenumbers in the solid state relative to those in the gas phase. The supramolecular studies confirmed the formation of centrosymmetric R 2 2(8) rings, which correspond to the formation of dimers that stack parallel to the b direction. Other weak C—H...π interactions, essential for crystal growth, were found. The UV–Vis spectroscopic analysis showed a donor–acceptor process, where the amino group acts as a donor and the pyridine and pyrimidine rings act as acceptors. The reactive sites of the molecule were identified and their quantitative values were defined using the electrostatic potential model proposed in the multifunctional wave function analyzer multiwfn. The calculated interaction energies between pairs of molecules were used to visualize the electrostatic terms as the leading factors against the dispersion factors in the crystal-growth process. The docking results showed that the amino group of the pyrimidine moiety was simultaneously anchored by hydrogen-bonding interactions with the Asp427 and His407 protein residues. This compound could be key for the realization of a series of syntheses of molecules that could be used as possible inhibitors of chronic myelogenous leukemia.

Intramolecular hydrogen bonds in the sulfonamide derivatives of oxamide, dithiooxamide, and biuret. FT-IR and DFT study, AIM and NBO analysis

Tetrahedron ◽  
2010 ◽  
Vol 66 (44) ◽  
pp. 8551-8556 ◽  
Author(s):  
B.A. Shainyan ◽  
N.N. Chipanina ◽  
T.N. Aksamentova ◽  
L.P. Oznobikhina ◽  
G.N. Rosentsveig ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Nbo Analysis ◽  
Dft Study ◽  
Intramolecular Hydrogen Bonds ◽  
Ft Ir ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Aim And Nbo

Variable temperature FT-IR studies on hydrogen adsorption on the zeolite (Mg,Na)-Y

2007 ◽  
Vol 253 (13) ◽  
pp. 5701-5704 ◽  
Author(s):  
C. Otero Areán ◽  
G. Turnes Palomino ◽  
M.R. Llop Carayol
Keyword(s):  
Hydrogen Adsorption ◽  
Variable Temperature ◽  
Ir Studies ◽  
Ft Ir
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