Optimization of molecular geometry of meta-substituted benzoic acids and their anions by gradient CNDO/2 method

1983 ◽  
Vol 48 (4) ◽  
pp. 1019-1029 ◽  
Author(s):  
Stanislav Böhm ◽  
Josef Kuthan
Keyword(s):  
Degrees Of Freedom ◽  
Molecular Geometry ◽  
Published Data ◽  
Benzoic Acids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Substituted Benzoic Acids

32 conformers of meta-substituted benzoic acids I and the corresponding anions II have been optimized with respect to all geometrical degrees of freedom by the title semiempirical MO approach. The calculated geometry characteristics are compared with some published data obtained by means of X-ray diffraction.

Optimization of molecular geometry of para-substituted benzoic acids and their anions by means of gradient CNDO/2 method

1982 ◽  
Vol 47 (12) ◽  
pp. 3393-3404 ◽  
Author(s):  
Stanislav Böhm ◽  
Josef Kuthan
Keyword(s):  
Diffraction Data ◽  
Molecular Geometry ◽  
Benzoic Acids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Substituted Benzoic Acids

21 conformers of benzoic acids I and corresponding anions II have been optimized by the title semiempirical MO approach. The calculated geometry characteristics are confronted systematically with X-ray diffraction data, and quality of the calculated parameters is critically evaluated.

Molecular Cocrystals of Carboxylic Acids. XXVI Adducts of the Amino-Substituted Benzoic Acids with Nitroaromatic Lewis Bases: the Influence of Associative Polyfunctional Substituents on Self-Assembly of Molecules in Cocrystallization Processes

1997 ◽  
Vol 50 (10) ◽  
pp. 977 ◽  
Author(s):  
Daniel E. Lynch ◽  
Graham Smith ◽  
Karl A. Byriel ◽  
Colin H. L. Kennard
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Self Assembly ◽  
Benzoic Acids ◽  
Aminobenzoic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lewis Bases ◽  
Aminobenzoic Acids ◽  
Substituted Benzoic Acids

A series of molecular adducts of the isomeric aminobenzoic acids with the nitro-substituted Lewis bases 2-chloro-5-nitropyridine, 5-nitroquinoline and 5-nitroisoquinoline has been prepared and characterized by using infrared spectroscopy and X-ray powder diffraction, and in four cases by single-crystal X-ray diffraction methods. These four compounds are the adducts of 3-aminobenzoic acid with 5-nitroquinoline [(C7H7NO2)(C9H6N2O2)], 4-aminobenzoic acid with 5-nitroquinoline [(C7H7NO2)2(C9H6N2O2)], 2-aminobenzoic acid with 5-nitroisoquinoline [(C7H7NO2)(C9H6N2O2)] and 4-aminobenzoic acid with 5-nitroisoquinoline [(C7H7N2O2)(C9H6N2O2)]. Other compounds described are the (1 : 1) adducts of 4-aminobenzoic acid with 2-chloro-5-nitropyridine, and 2-aminobenzoic acid with 5-nitroquinoline. All adducts involve hydrogen-bonding network associations while in none of the examples is any proton transfer involved.

Molecular Cocrystals of Carboxylic Acids. XIII. Spectral Characterization of the Adducts of Triphenylphosphine Oxide With Substituted Benzoic Acids and the Crystal Structures of the 1 : 1 Adducts With 2,4,6-Trinitrobenzoic Acid and 3,5-Dinitrobenzoic Acid

1993 ◽  
Vol 46 (10) ◽  
pp. 1535 ◽  
Author(s):  
DE Lynch ◽  
G Smith ◽  
NJ Calos ◽  
CHL Kennard ◽  
AK Whittaker ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Triphenylphosphine Oxide ◽  
Benzoic Acids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Proton ◽  
Phosphoryl Oxygen ◽  
Substituted Benzoic Acids ◽  
Convenient Technique

The 1:1 adducts of triphenylphosphine oxide with the 2-, 3- and 4-nitro-, 3,5-dinitro-, and 2,4,6-trinitro-substituted benzoic acids have been prepared, and characterized by infrared and 31P n.m.r. spectroscopy. The crystal structures of two of these adducts, (triphenylphosphine oxide-3,5-dinitrobenzoic acid) and ( triphenylphosphine oxide-2,4,6-trinitrobenzoic acid), have been determined by X-ray diffraction. In all examples, the presence of single directed hydrogen bonds between the phosphoryl oxygen and the carboxylic acid proton is confirmed. For the X-ray structures, the O…O distances are 2.54(4) and 2.55(1)Ǻ respectively. Solid-state 31P n.m.r. spectroscopy has also proved a convenient technique for the detection of the presence of a single conformational adduct type in cocrystals.

Designing Linear Hydrogen-Bonded Arrays by Using Substituted Charge-Transfer Complexes. The Crystal Structure of the 1 : 1 Adduct of Indole-2-carboxylic Acid with 3,5-Dinitrobenzoic Acid

1998 ◽  
Vol 51 (11) ◽  
pp. 1019 ◽  
Author(s):  
Daniel E. Lynch ◽  
Graham Smith ◽  
Karl A. Byriel ◽  
Colin H. L. Kennard
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Second Harmonic ◽  
Charge Transfer Complexes ◽  
Benzoic Acids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Linear Optical Properties ◽  
Substituted Benzoic Acids ◽  
Indole 3 Acetic Acid

Five adducts consisting of carboxylic acid-substituted indoles with nitro-substituted benzoic acids have been synthesized and tested for second-order non-linear optical properties. These were indole-2-carboxylic acid with 2,4-dinitrobenzoic acid (1), 3,5-dinitrobenzoic acid (2), and 2,4,6-trinitrobenzoic acid (3), and indole-3-acetic acid with 3,5-dinitrobenzoic acid (4), and 2,4,6-trinitrobenzoic acid (5). Compound (2) produced clear, yellow crystals (space group P -1 with a 6·8400(7), b 15·150(2), c 16·097(2) Å, α 84·911(9), β 87·088(10), γ 77·865(9)°, Z 4) which allowed the structure to be determined by X-ray diffraction. Of the five adducts, compounds (3) and (5) gave second harmonic intensities of 0·15 and 0·16 times respectively that of a urea standard.

Molecular Cocrystals of Carboxylic Acids. XXI. The Role of Secondary Group Interactions in Adduct Formation Between 2-Aminopyrimidine and Substituted Benzoic Acids: the Crystal Structures of the Adducts With o-Phthalic Acid, o-Nitrobenzoic Acid, o-Aminobenzoic Acid and m-Aminobenzoic Acid

1995 ◽  
Vol 48 (6) ◽  
pp. 1151 ◽  
Author(s):  
G Smith ◽  
JM Gentner ◽  
DE Lynch ◽  
KA Byriel ◽  
CHL Kennard
Keyword(s):  
Phthalic Acid ◽  
Adduct Formation ◽  
Benzoic Acids ◽  
Aminobenzoic Acid ◽  
X Ray Diffraction ◽  
Group Interactions ◽  
X Ray ◽  
Nitrobenzoic Acid ◽  
Substituted Benzoic Acids

The crystalline adducts of 2-aminopyrimidine (2-ap) with a series of mainly ortho-substituted benzoic acids, o-phthalic acid ( opht ) [(2-ap)( opht )] (1), 2-nitrobenzoic acid (2-nba) [(2-ap)(2-bna)2] (2), 2-aminobenzoic acid (2-aba) [(2-aba) [(2-ap)(2-aba)2] (3) and 3-aminobenzoic acid (3-aba) [(2-ap)(3-aba)] (4) have been prepared and their hydrogen-bonding motifs characterized by using single-crystal X-ray diffraction. The role of substituent groups in secondary associations with cocrystal formation is considered for the 2-aminopyrimidine system.

scholarly journals Pressure-induced Jahn-Teller Switch in the Homoleptic Hybrid Perovskite [(CH3)2NH2]Cu(HCOO)3: Orbital Reordering by Unconventional Degrees of Freedom

2021 ◽  
Author(s):  
Rebecca Scatena ◽  
Michał Andrzejewski ◽  
Roger D Johnson ◽  
Piero Macchi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Coordination Polymer ◽  
Degrees Of Freedom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite ◽  
Jahn Teller

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...

scholarly journals Emergent long-range magnetic order in ultrathin (111)-oriented LaNiO3 films

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Margaret M. Kane ◽  
Arturas Vailionis ◽  
Lauren J. Riddiford ◽  
Apurva Mehta ◽  
Alpha T. N’Diaye ◽  
...  
Keyword(s):  
Long Range ◽  
Degrees Of Freedom ◽  
Magnetic Order ◽  
Magnetic Ordering ◽  
Anomalous Hall Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Range Magnetic Order ◽  
Film Substrate ◽  
Long Range Magnetic Order

AbstractThe emergence of ferromagnetism in materials where the bulk phase does not show any magnetic order demonstrates that atomically precise films can stabilize distinct ground states and expands the phase space for the discovery of materials. Here, the emergence of long-range magnetic order is reported in ultrathin (111) LaNiO3 (LNO) films, where bulk LNO is paramagnetic, and the origins of this phase are explained. Transport and structural studies of LNO(111) films indicate that NiO6 octahedral distortions stabilize a magnetic insulating phase at the film/substrate interface and result in a thickness-dependent metal–insulator transition at t = 8 unit cells. Away from this interface, distortions relax and bulk-like conduction is regained. Synchrotron x-ray diffraction and dynamical x-ray diffraction simulations confirm a corresponding out-of-plane unit-cell expansion at the interface of all films. X-ray absorption spectroscopy reveals that distortion stabilizes an increased concentration of Ni2+ ions. Evidence of long-range magnetic order is found in anomalous Hall effect and magnetoresistance measurements, likely due to ferromagnetic superexchange interactions among Ni2+–Ni3+ ions. Together, these results indicate that long-range magnetic ordering and metallicity in LNO(111) films emerges from a balance among the spin, charge, lattice, and orbital degrees of freedom.

The Molecular Geometry of Diastereoisomeric Bis[α-(9-anthryl)ethyl] Ethers

1985 ◽  
Vol 38 (9) ◽  
pp. 1417 ◽  
Author(s):  
H Becker ◽  
VA Patrick ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Least Squares ◽  
Dihedral Angle ◽  
Molecular Geometry ◽  
Dihedral Angles ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Meso Form ◽  
Aromatic Systems

The crystal structures of racemic bis [α-(9-anthryl)] ether and its meso form have been determined by single-crystal X-ray diffraction methods at 295 K, being refined by least squares to residuals of 0.053 and 0.041 for 1868 and 3568 independent 'observed' reflections respectively. Crystals of the racemate are orthorhombic, Pcab, a 23.07(1), b 19.85(2), c 10.241(8) Ǻ, Z 8. Crystals of the meso form are triclinic, Pī , a 19.032(12), b 14.207(11), c 9.451(8) Ǻ, α 79.46(6), β 89.68(6), γ 68.97(5)°, Z 4. In the racemate , the dihedral angle between the methyl groups along the ether bonds is 12°, and the short axes of the anthracene moieties lie at an angle of about 120°. In the meso compound, for the two molecules the dihedral angles between the methyl groups along the ether bonds are 90 and 93°, the angle between the two anthracene moieties is 90°, and the interplanar angles between the partly overlapping aromatic systems are 46 and 43°.

X-Ray Diffraction and Reflectometry Investigation of Interdiffusion In Sputtered Niobium-Tungsten Bilayers

1999 ◽  
Vol 562 ◽  
Author(s):  
U. Welzel ◽  
P. Lamparter ◽  
E. J. Mittemeijer
Keyword(s):  
Diffusion Coefficients ◽  
Low Temperatures ◽  
Qualitative Evaluation ◽  
Diffraction Line ◽  
Published Data ◽  
Concentration Profiles ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray

ABSTRACTInterdiffusion in sputtered niobium(45nm)-tungsten(45nm) bilayers upon annealing at low temperatures (T<1000K) has been investigated using X-ray reflectometry and diffraction. The accompanying changes in macrostress and microstructure have been characterized by applying the X-ray diffraction sin2ψ T method and by qualitative evaluation of the diffraction line broadening, respectively. Annealing causes, besides interdiffusion, changes of macrostress and decrease of microstructural imperfection. Concentration profiles corresponding to diffusion lengths of only a few nanometers were determined by simulation of the measured reflectivity patterns. The values obtained for the diffusion coefficients are compared with corresponding values obtained by extrapolation from published data for bulk materials at much higher temperatures.

Crystal structure of Tetracyclo[5,3,1,12,6,04,9]dodecane (iceane)

1977 ◽  
Vol 30 (8) ◽  
pp. 1837 ◽  
Author(s):  
DPG Hamon ◽  
CL Raston ◽  
GF Taylor ◽  
JN Varghese ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rigid Body ◽  
Least Squares ◽  
Title Compound ◽  
Molecular Geometry ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Hexagonal Close Packed

The crystal structure of the title compound, C12H18, has been determined at 295 K by X-ray diffraction and refined by full-matrix least squares to a residual of 0.049 for 216 ?observed? reflections; molecular geometry has been corrected for the effects of thermal motion using a rigid body approximation. Crystals are hexagonal, P63/m, a = 6.582(1), c = 11.843(3) Ǻ, Z = 2, the molecules occupying a hexagonal close- packed array.

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