Dihedral Angle Research Articles

Crystal structure and Hirshfeld surface analysis of 6,6'-dimethyl-2,2'-bi-pyridine-1,1'-diium tetra-chlorido-cobaltate(II).

In the title mol-ecular salt, (C12H14N2)[CoCl4], the dihedral angle between the pyridine rings of the cation is 52.46 (9)° and the N-C-C-N torsion angle is -128.78 (14)°, indicating that the ring nitro-gen atoms are in anti-clinal conformation. The Cl-Co-Cl bond angles in the anion span the range 105.46 (3)-117.91 (2)°. In the extended structure, the cations and anions are linked by cation-to-anion N-H⋯Cl and C-H⋯Cl inter-actions, facilitating the formation of R 4 4(18) and R 4 4(20) ring motifs. Furthermore, the crystal structure features weak anion-to-cation Cl⋯π inter-actions [Cl⋯π = 3.4891 (12) and 3.5465 (12) Å]. Hirshfeld two-dimensional fingerprint plots revealed that the most significant inter-actions are Cl⋯H/H⋯Cl (45.5%), H⋯H (29.0%), Cl⋯C/C⋯Cl (7.8%), Cl⋯N/N⋯Cl (3.5%), Cl⋯Cl (1.4) and Co⋯H (1%) contacts.

Syntheses and X-ray Structure of N-(Benzothiazol-2-yl)-3-chlorobenzamide

The reaction of 3-chloro-benzoyl chloride and 2-aminobenzothiazole in the presence of potassium thiocyanate yielded a yellowish solid C15H10ClN3OS2 (1). Reaction of 1 with cobalt chloride yield a yellowish solid C14H11ClN2O2S (2) which gives crystal suitable for X-ray analyses. The compounds were characterized by elemental analyses FTIR spectroscopy and melting point measurement. Compound 2 crystallizes in the triclinic space group Pī with the following parameters: a = 7.0299(2) Å b = 7.0466(2) Å c = 14.5490(2) Å a = 103.844(3)° β = 92.929(2)° g = 107.291(3) V = 662.33(4) Å3 Z= 2 R1 = 0.030 wR2 = 0.034. The asymmetric unit of (2) consists of one molecule in which the 3-chloro phenyl moiety and the benzothiazole-2-yl moiety form a dihedral angle of 6.417(4)°. An intramolecular O—H···O hydrogen bond occurs. In the crystal O—H···N and N—H···O hydrogen bonds link the molecules forming layers parallel to the ac plane.

Stabilizing Bifurcated Hydrogen Bond in 8-Aminoquinoline Appended Peptides.

The hydrogen bonding interaction between an amide N-H and the amide N of the preceding residue is prevalent in proline-containing proteins and peptides. However, the N-H⋅⋅⋅N hydrogen bonding interaction is rare in non-prolyl natural peptides due to restricted dihedral angles. Herein, we stabilize this type of interaction in 8-aminoquinoline appended non-prolyl peptides through bifurcated N⋅⋅⋅H⋅⋅⋅N hydrogen bond. The 8-aminoquinoline-incorporated model peptides 2 a-i were designed, synthesized, and the crystal structures of 2 a-c and 2 i were solved. Analysis of crystal data reveals that the amide N-H of aminoquinoline is involved in bifurcated hydrogen bonding interaction with the nitrogen of the preceding amino acid residue and the nitrogen in quinoline. Analysis of crystal packing, Hirshfeld surface and fingerprint plots confirms that the intermolecular O⋅⋅⋅H contacts significantly contribute to stabilizing bifurcated N⋅⋅⋅H⋅⋅⋅N hydrogen bonding interaction. Furthermore, NMR experiments and CD spectroscopy were conducted to examine the preferred conformation in solution, and the data corroborate with the crystal structure conformation.

Long-chain alkyl groups enhance the water-repellent properties of short-chain perfluoroalkyl compounds: An experimental and computer simulation study

The polymers composed of long-chain stearyl acrylate (SA) and short-chain (perfluorohexyl) ethyl methacrylate (FA) were synthesized using the emulsion polymerization technique. Cotton fabric was then coated with these polymers to act as a water-repellent agent. Surface wetting properties of the coated cotton fabric were tested. In a peculiar manner, the water repellency of the coatings did not improve with the increase of the perfluorohexyl group. Therefore, the polymer's crystallization behaviors and melting temperature were assessed through differential scanning calorimetry (DSC) and computer simulation. A computer simulation was employed to analyze the density, surface energy, element distribution, chain arrangement, bond order parameter, and surface images of the polymer film. The results suggest that water repellency is not directly related to the film's surface energy but rather depends on the element proportion, bond angle distribution, and dihedral angle torsion energy. The key points will serve as invaluable indicators for the development of a highly efficient water-repellent coating with a low proportion of fluorine and provide a more sustainable solution for water-repellent applications.

Modification of the N-methyl-4,5-diazacarbazole D-π-A with a π-conjugated bridge to enhance excited-state properties for superior utilization in green energy applications: A theoretical approach

In organic photovoltaic technology, tailoring the acceptor or donor unit to enhance intramolecular charge transfer is a well-known approach, however, the effect of modifying conjugated bridge units is an underdeveloped phenomenon. In this study, this approach has been focused, where a series of conjugated bridges including, a) electron-excessive heterocycles, b) electron-deficient heterocycles, and c) short-chain unsaturated hydrocarbons have been substituted from thiophene bridge-containing D-π-A; N-methyl-4,5-diazacarbazole (donor) and bay-annulated indigo (acceptor) molecule. This quantum chemical study aims to investigate the effect of various types of π-conjugated bridges on the electronic structure and solar cell activity of already reported material. The selected π-conjugated bridges include electron-excessive (furan, pyrrole, & thiophene) and electro-deficient (diazine, tetrazine, & pyridine) heterocycles, and short-chain hydrocarbons (ethylene & ethyne). The optimized structural parameters e.g., dihedral angles (θ), distortion energies (Edis), & bond distances (d), and electronic behaviour i.e., Frontier Molecular Orbitals (FMO), Electrostatic Potentials (ESP), Density of States (DOS) spectra, dipole moments (μ), and absorption spectra of the hypothetically designed molecules are estimated using density functional theory calculations. The solar cell proficiency is investigated with transition dipole moment (μT), reorganization energy (RE), Transition density matrix (TDM), exciton binding energy (Eb), and open circuit voltage (Voc). Our finding encompassed that our designed D-π-A molecules show significant improvement in their electronic behaviour, especially when the thiophene bridge of the reference molecule is substituted with the excess electron heterocycles, especially pyrrole. The HOMO-LUMO gap of this particular molecule (MPy) is reduced to 2.07 eV, resulting in the significant charge transfer between donor and acceptor units (0.15 e-). Moreover, the results of RE, TDM, Eb, and Voc also support the high solar cell efficiency of pyrrole-containing molecules.

Conformational Analysis of Trifluoroacetyl Triflate, CF3C(O)OSO2CF3: Experimental Vibrational and DFT Investigation

The conformations of trifluoroacetyl triflate, CF3C(O)OSO2CF3, were investigated through experimental vibrational methods (gas-phase FTIR, liquid-phase Raman, and Ar matrix FTIR spectroscopy) and density functional theory (DFT) calculations. A potential energy surface was computed using the B3P86/6-31+g(d) approximation as a function of the dihedral angles τ1 = CC−OS and τ2 = CO−SC. The surface reveals three minima, which were further optimized using the B3LYP method with various basis sets (6-31++G(d), 6-311++G(d), tzvp, and cc-pvtz). The global minimum corresponds to a syn–anti conformer (the C=O double-bound syn with respect the O−S single bond and the C−O single bond anti with respect to S−C single bond). The other two minima represent enantiomeric syn–gauche forms. The Ar matrix FTIR spectrum exhibited clear evidence of the presence of two conformers. Furthermore, the randomization process observed following broadband UV–visible irradiation facilitated the identification of the IR absorption of each conformer. Based on the Ar matrix FTIR experiments, the vapour phase of trifluoroacetyl triflate at room temperature was composed of approximately 60–70% of the syn–anti conformer and 30–40% of the syn–gauche form.

Femoral anteversion linked to the inability to squat: Analysis of CT images in the patient and control groups.

Many patients who cannot squat well in a neutral toe position can only squat in an excessively out-toeing position. This excessive out-toeing squat is thought to be caused by rotational problems of the lower extremities. In this study, we aimed to identify the cause for the inability to squat by measuring and comparing femoral and tibial torsion between an excessive out-toeing squat patient group and a control group representing the general population. Between 2008 and 2022, a patient group comprising 50 lower extremities with excessive out-toeing squats was established. A control group representing the general population was selected from patients aged 0 to 29 years, who underwent lower-extremity CT angiography between 2012 and 2022, using the Clinical Data Warehouse with exclusion criteria applied. A total of 94 lower extremities were included in the control group. The femoral torsional angle (FTA) and tibial torsional angle (TTA) of both groups were measured and compared using Student t test. Additionally, 30 each of those with the highest and lowest 30 FTA values were selected from the patient and control groups, and the TTA was compared between the high- and low-FTA groups using Student t test. The mean FTA was 0.34° (SD, 11.11°) in the patient group and 10.14° (SD, 11.85°) in the control group, with a mean difference of 9.8° and P < .001. The mean TTA was 27.95° (SD, 7.82°) in the patient group and 32.67 ° (SD, 7.58°) in the control group, with a mean difference of 4.72° (P = .001). The mean TTA was 34.3° (SD, 7.72°) in the high-FTA group and 28.17° (SD, 8.35°) in the low-FTA group, with a mean difference of 6.13° (P = .005). Patients with excessive out-toeing squat showed lower FTA and TTA values than the general population. Furthermore, although a correlation between FTA and TTA was not established through Pearson correlation analysis, a tendency was observed where a decrease in FTA was associated with a decrease in TTA. Based on these results, decreased FTA was demonstrated to be one of the major causes of excessive out-toeing squats.

Computational study on metal-free dye-sensitized solar cells utilizing heterocyclic derivative π-spacers with open and fused rings: Design and analysis of D-π-A-π-A dye sensitizers

A series of metal-free dye-sensitized solar cells featuring a D-π-A-π-A configuration is devised, employing various heterocyclic derivative π-spacers in both open and fused configurations. Employing DFT and TD-DFT methods, the optoelectronic and photovoltaic characteristics of the dye are scrutinized. To evaluate the impact of diverse heterocyclic spacers, structural parameters such as distance and dihedral angle, alongside thermodynamic metrics including electron injection efficiency (ΔGinject), regeneration efficiency (ΔGreg), light harvesting efficiency (LHE), open-circuit photovoltage (VOC), and short-circuit current density (JSC) are assessed. Results indicate that selected dyes with open and fused configurations of heterocyclic π-spacers such as O-CNC-2, O-CNN-4, O-NNC-7, O-NNN-8, F-NNC-2, and F-NNN-1 exhibited superior electron density distribution, higher ΔGinject, lower ΔGreg, elevated VOC, and JSC compared to their counterparts based on open configurations. These D-π-A-π-A dyes can emerge as promising candidates for future applications in solar cells.

Crystal structures of 1,1'-bis-(carb-oxy-meth-yl)-4,4'-bipyridinium derivatives.

The crystal structures of 2-[1'-(carb-oxy-meth-yl)-4,4'-bi-pyridine-1,1'-diium-1-yl]acetate tetra-fluoro-borate, C14H13N2O4 +·BF4 - or (Hbcbpy)(BF4), and neutral 1,1'-bis-(carboxyl-atometh-yl)-4,4'-bi-pyridine-1,1'-diium (bcbpy), C14H20N2O8, are reported. The asymmetric unit of the (Hbcbpy)(BF4) consists of a Hbcbpy+ monocation, a BF4 - anion, and one-half of a water mol-ecule. The BF4 - anion is disordered. Two pyridinium rings of the Hbcbpy+ monocation are twisted at a torsion angle of 30.3 (2)° with respect to each other. The Hbcbpy monocation contains a carb-oxy-lic acid group and a deprotonated carboxyl-ate group. Both groups exhibit both a long and a short C-O bond. The cations are linked by inter-molecular hydrogen-bonding inter-actions between the carb-oxy-lic acid and the deprotonated carboxyl-ate group to give one-dimensional zigzag chains. The asymmetric unit of the neutral bcbpy consists of one-half of the bcbpy and two water mol-ecules. In contrast to the Hbcbpy+ monocation, the neutral bcbpy mol-ecule contains two pyridinium rings that are coplanar with each other and a carboxyl-ate group with similar C-O bond lengths. The mol-ecules are connected by inter-molecular hydrogen-bonding inter-actions between water mol-ecules and carboxyl-ate groups, forming a three-dimensional hydrogen-bonding network.

Java Script Programs for Calculation of Dihedral Angles with Manifold Equations

Java Script programs for calculation dihedral angles from NMR data with manifold equations of 3-Sphere approach: rectangle, Villarceau circles of cyclide (Torus – Dupin Cyclide), polar equations, Euler-Conic. Manifolds are curves or surface in higher dimension used for calculation of dihedral angles under wave character of NMR data, carbon and/or proton chemical shift δ&amp;lt;sub&amp;gt;Xn&amp;lt;/sub&amp;gt;[ppm] and vicinal coupling constant &amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;&amp;lt;I&amp;gt;J&amp;lt;/I&amp;gt;&amp;lt;sub&amp;gt;HnHn+1&amp;lt;/sub&amp;gt;[Hz]. 3-Sphere approach for calculation of the dihedral angles from NMR data in four steps: 1. Prediction, or more exactly calculation of the dihedral angles from vicinal coupling constant with trigonometric equations, 2. Calculation of the dihedral angles from manifold equations; 3. Building units from angle calculated with one of the manifold equations; 4. Calculation the vicinal coupling constant of the manifold dihedral angle. In this paper are presented Java Script programs of step 2 and from step 3 only the Java Script program for calculation of seven sets angles. The bond distances l&amp;lt;sub&amp;gt;CnCn+1&amp;lt;/sub&amp;gt;[A&amp;lt;sup&amp;gt;0&amp;lt;/sup&amp;gt;] between two atoms of carbon are under different polar equations (&amp;lt;i&amp;gt;i.e.&amp;lt;/i&amp;gt; limaçons or cardioid, rose or lemniscale), our expectation was to find different manifold equations for calculation the best angle, differences are smaller but can be find sometimes a preferred one for a vicinal coupling constant. 3-Sphere approach has the advantages of calculation from vicinal angle or/and chemical shift the dihedral angle, tetrahedral angle and the bond distance l&amp;lt;sub&amp;gt;CnCn+1&amp;lt;/sub&amp;gt;[A&amp;lt;sup&amp;gt;0&amp;lt;/sup&amp;gt;], with application on conformational and configurational analysis.

Hybridization makes the difference: [2Oxa.2Oxa.2Oxa] a sp2-Carbon dominated Lehn-type cryptand - Prediction of ion selectivity by quantum chemical calculations. XVIII

Substituting the O-C2H4-O-moiety of [2.2.2] by the O2CCO2-core of oxalic acid leads to the new Lehn-type cryptand [M ⊂ 2Oxa.2Oxa.2Oxa]m+. We explored by quantum chemical methods (B3LYP/LANL2DZp) the complexation behaviour and compared it with the original cryptand [2.2.2]. The cryptands [2Oxa.2Oxa.2Oxa] and [2.2.2] exhibit the same ion selectivity against alkaline and alkaline earth metal cation (K+ followed by Rb+; Ba2+ preferred over Sr2+). The exchange of the OC2H4O-moiety by the O2CCO2-moiety (the subsequent exchange of sp3- by sp2-carbon atoms) makes [2Oxa.2Oxa.2Oxa] less flexible in the OCCO-diether angle as [2.2.2]. This rigidity results in higher complexation energies for [M ⊂ 2Oxa.2Oxa.2Oxa]m+ and that the twisting of the dihedral angle CN…NC improves the nesting of the guest cations in the cryptand [2Oxa.2Oxa.2Oxa].

Unraveling the role of non-planarity of free base porphyrins in intermolecular hydrogen bonding interactions with phenols

Three different types of meso‑substituted freebase porphyrins (H2TTP, H2TMP and H2DDMP) with varied number and nature of electron donating groups (-CH3 and –OCH3) were synthesized. The molecular interactions of the porphyrins with different phenol derivative were explored using single crystal X-ray, NMR and their affinity by varied spectroscopic techniques. All three freebase porphyrins undergo strong intermolecular interactions with 2,4,6-trinitrophenol (TNP) and crystallized in a triclinic crystal system with iso-structural behaviour. The crystal lattices are stabilized through intermolecular hydrogen bonding interactions (N–H∙∙∙O and C–H∙∙∙O) and electrostatic interactions. Increases in the non-planarity of freebase porphyrins enhance the reactivity which results in the formation of picrate anions with 1:2 adduct formation by proton transfer process. The role of weak intermolecular interactions was analysed and quantified through Hirshfeld surface and finger print analysis. DFT studies revealed that the electron-donating effect of the methoxy group plays a major role in decreasing HOMO-LUMO gap and in-plane co-operation through the decrease in the dihedral angles. The electron density at bond critical points follows the order H2TTP.2TNP>H2TMP.2TNP>H2DDMP.2TNP. Absorption and emission studies showed that dramatic changes in the Soret and Q-band pattern and the binding constants were altered with different phenols of varied pKa. The stabilization of molecular adducts were analyzed in correlation with 1H- NMR study to reveal the involvement of the hydrogen bonding.

Neighbor effect on conformational spaces of alanine residue in azapeptides

The conformational properties of Alanine (Ala) residue have been investigated to understand protein folding and develop force fields. In this work, we examined the neighbor effect on the conformational spaces of Ala residue using model azapeptides, Ac-Ala-azaGly-NHMe (3, AaG), and Ac-azaGly-Ala-NHMe (4, aGA1). Ramachandran energy maps were generated by scanning (φ, ψ) dihedral angles of the Ala residues in models with the fixed dihedral angles (φ = ±90°, ψ = ±0° or ±180°) of azaGly residue using LCgau-BOP and LCgau-BOP + LRD functionals in the gas and water phases. The integral-equation-formalism polarizable continuum model (IEF-PCM) and a solvation model density (SMD) were employed to mimic the solvation effect. The most favorable conformation of Ala residue in azapeptide models is found as the polyproline II (βP), inverse γ-turn (γ′), β-sheet (βS), right-handed helix (αR), or left-handed helix (αL) depending on the conformation of neighbor azaGly residue in isolated form. Solvation methods exhibit that the Ala residue favors the βP, δR, and αR conformations regardless of its position in azapeptides 3 and 4 in water. Azapeptide 5, Ac-azaGly-Ala-NH2 (aGA2), was synthesized to evaluate the theoretical results. The X-ray structure showed that azaGly residue adopts the polyproline II (βP) and Ala residue adopts the right-handed helical (αR) structure in aGA2. The conformational preferences of aGA2 and the dimer structure of aGA2 based on the X-ray structure were examined to assess the performance of DFT functionals. In addition, the local minima of azapeptide 6, Ac-Phe-azaGly-NH2 (FaG), were compared with the previous experimental results. SMD/LCgau-BOP + LRD methods agreed well with the reported experimental results. The results suggest the importance of weak dispersion interactions, neighbor effect, and solvent influence in the conformational preferences of Ala residue in model azapeptides.

The effect of halides on Cd(II)-based metal coordination complexes with indazole and benzimidazole skeletons: Crystal structure, Hirshfeld surface analysis and properties

A set of Cd(II)-based metal coordination complexes with indazole and benzimidazole scaffolds, namely, [Cd(IZBI)Cl2]n·H2O (1) [Cd(IZBI)Br2]n·H2O (2) [Cd(IZBI)I2]·H2O (3) (IZBI stands for 3-(1H-benzimidazol-2-yl)-1H-indazole), were obtained through solvothermal reaction conditions. They have been structurally characterized by elemental analysis, single-crystal X-ray diffraction and IR spectra. Single-crystal X-ray diffraction analysis reveals that complexes 1–3 show one-dimensional polymeric, dimeric and mono-nucleic features, respectively, which indicates that the halide anions affect the final structure of metal coordination complexes. The luminescent maximal peaks can be observed 448, 456 and 462 nm for complexes 1–3, respectively. Compared with the emission peak of IZBI, there exist bathochromic phenomena for metal coordination complexes 1–3, where the red-shifted values can be observed to be 46, 54 and 60 nm, respectively. The order of the photoluminescent emission peaks is summarized as the following: 3 > 2 > 1. The single-crystal X-ray diffraction analysis shows that it occurs the order of the dihedral angles between the pyrazole and imidazole rings (3 < 2 < 1). The Hirshfeld analysis demonstrates that there is a positive correlation between the sequence of H∙∙∙C/C∙∙∙H intermolecular contacts and the dihedral angles formed between the pyrazole and imidazole rings, which is negative correlation with the positions of the luminescent maxima. Additionally, the thermostable behaviors of these complexes were inspected in detail.

Transition Radiation on a Conducting Target Shaped as a Right Dihedral Angle

Transition Radiation on a Conducting Target Shaped as a Right Dihedral Angle

Design of a Fourier-transform spectrometer for detector characterization on CMB polarization telescope

We present the design of a Fourier-transform spectrometer (FTS) tailored for operation within the frequency range of 75 GHz to 300 GHz, offering a spectral resolution surpassing 2 GHz. This FTS can be used for characterizing detectors on a Cosmic Microwave Background (CMB) Polarization Telescope for the observation of CMB B-mode polarization. The FTS instrument is divided into the primary part, housing a Martin-Puplett interferometer (MPI) module, and the coupled part, which incorporates a beam expanding module and a beam steering module. An in-depth performance analysis focusing on the MPI module, involving considerations such as the orientation of the beam splitter, dihedral angle of the roof-top mirrors, and positioning uncertainty of the scanning mirror, has been conducted by using a simulation tool. Results indicate that the spectral characteristic remains unaffected by variations in the Reflection/Transmission ratio of the beam splitter, with any deviation from the 1:1 ratio uniformly decreasing intensity. The impact of dihedral angle errors of roof-top mirrors (below 0.02 degrees) and positioning uncertainty in the scanning mirror (lower than 3 × 10-3 mm) on the system performance is acceptable for the design of the FTS. The beam expanding module is capable of enlarging the output beam of the MPI module to roughly a 150 mm-radius. The beam steering module allows for directional adjustments within the range of +17 degrees to -17 degrees relative to the normal of the target plane. Preliminary testing on the MPI prototype reveals a spectral resolution of 1.5 GHz for the measured frequency.

Nonlinear characteristics of torsional stiffness of a coilable mast with triangular section

With numerous applications coilable masts in high-precision astronomical observations, such as X-ray source observations, it is important to investigate mast stiffness. To date, there have been many studies on the bending stiffness of coilable masts, but few studies on their torsional stiffness, especially regarding the nonlinear characteristics of torsional stiffness of coilable masts under large torsional deformation. In this paper, a nonlinear analysis method is presented to examine the torsional stiffness of coilable masts with triangular sections. Based on the second-order bending buckling hypothesis of battens under large torsion deformation, the nonlinear relationship between torsional torque and torsional angle is obtained by analyzing torsional deformation and force of coilable masts. This method is used to analyze the torsional stiffness nonlinearity of a certain type of coilable mast which will be used in a practical application in the future and the results are verified by simulation and testing. The comparison results show that the error is within the acceptable range, which proves the effectiveness of the proposed method.

Carotid Dolichoarteriopathies: A Comprehensive Overview

Carotid dolichoarteriopathies (CDA) represent a group of morphological abnormalities, with changes in the geometry and tortuosity of the carotid arteries. They were described in 1925 for the first time and were classified in three types according to the angle of torsion, in tortuosity (angle &gt; 90°), coiling (S-shaped curve or loop) and kinking (angle &lt; 90°). The pathophysiology of CDA is controversial and includes congenital mechanisms, genetic factors, connective tissue diseases, acquired mechanisms which can be associated with but not dependent on cardiovascular risk factors, and anomalies of the cervical spine. CDA have been associated with different cardiovascular and cerebrovascular events secondary to hemodynamic abnormalities, thromboembolism and cerebrovascular insufficiency and ischemia. However, the evidence is limited and for some authors they are more of a curiosity than a real predictor of ischemic events. Other studies support the clinical value of the diagnosis and follow-up of CDA and their understanding not only by internists, cardiologists and neurologists, but also by surgeons and otolaryngologists. Several authors proposed different therapeutic strategies to correct CDA, including surgical procedures. However, the indications and management approaches are controversial, and further randomized, multicenter, prospective studies are required to determine the most appropriate course of action. Until then, imaging techniques remain the basis for the etiologic diagnosis of cerebrovascular adverse events when all other causes have been excluded, and close clinical monitoring and follow-up of patients remain key strategies for the prevention of secondary events.

2-(Pyridin-4-yl)-2,3-di-hydro-1H-naphtho-[1,8-de][1,3,2]di-aza-borinine.

The title compound, C15H12BN3, is a type of di-aza-borinane featuring substitution at 1, 2, and 3 positions in the nitro-gen-boron six-membered heterocycle. It is comprised of two almost planar units, the pyridyl ring and the Bdan (dan = 1,8-di-aminona-phtho) group, which subtend a dihedral angle of 24.57 (5)°. In the crystal, the mol-ecules are linked into R 4 4(28) hydrogen-bonding networks around the fourfold inversion axis, giving cyclic tetra-mers. The mol-ecules form columnar stacks along the c axis.

Crystal structure of 1-(1,3-benzothiazol-2-yl)-3-(4-bromobenzoyl)thiourea

The chemical reaction of 4-bromobenzoylchloride and 2-aminothiazole in the presence of potassium thiocyanate yielded a white solid formulated as C15H10BrN3OS2, which consists of 4-bromobenzamido and 2-benzothiazolyl moieties connected by a thiourea group. The 4-bromobenzamido and 2-benzothiazolyl moieties are in a trans conformtion (sometimes also called s-trans due to the single bond) with respect to the N—C bond. The dihedral angle between the mean planes of the 4-bromophenyl and the 2-benzothiazolyl units is 10.45 (11)°. The thiourea moiety, —C—NH—C(=S) —NH— fragment forms a dihedral angle of 8.64 (12)° with the 4-bromophenyl ring and is almost coplanar with the 2-benzothiazolyl moiety, with a dihedral angle of 1.94 (11)°. The molecular structure is stabilized by intramolecular N—H...O hydrogen bonds, resulting in the formation of an S(6) ring. In the crystal, pairs of adjacent molecules interact via intermolecular hydrogen bonds of type C—H...N, C—H...S and N—H...S, resulting in molecular layers parallel to the ac plane.