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1.
RSC Adv ; 14(25): 18011-18063, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38847003

RESUMO

Acyl thioureas represent a privileged moiety with vast potential applicability across diverse fields, making them the subject of extensive research efforts. The inherent flexibility of thiourea facilitates the synthesis of a wide range of core structures with diverse functionalities and properties. The distinctive presence of hard and soft donor sites renders acyl thioureas inclined to act as versatile ligands, thereby engendering a diverse array of metal complexes incorporating acyl thiourea as a pivotal ligand. Extensive investigations into the synthesized acyl thioureas and their derivatives have culminated in the elucidation of their substantial potential across a spectrum of applications, spanning biological activities, materials chemistry, catalysis, and beyond. This literature review represents a continuation of our ongoing endeavor to compile comprehensive data on research endeavors concerning acyl thioureas over the past two years.

2.
BMC Chem ; 17(1): 97, 2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37580804

RESUMO

Energetic heterocycles, including pyridines, triazoles, and tetrazoles, exhibit greater density, heats of formation, and oxygen balance compared to their carbocyclic counterparts, making them a promising approach for synthesizing novel bis-tetrazole acetamides. Synthesized compounds A-F, some of which feature a chlorine atom attached to the phenyl ring, serve as valuable synthons for aryl coupling reactions. Analysis via 1H-NMR and 13C-NMR spectroscopy, as well as density functional considerations through B3LYP functional correlation with 6-311 + + G(d) and 6-31G(d) basis set, revealed the observed LUMO/HOMO energies and charge transfer within the molecule. Additionally, the dipole moment, chemical hardness, softness, ionization potential, local reactivity potential via Fukui indices and thermodynamic properties (entropy, enthalpy, and Gibbs free energy) of the molecule were calculated through density functional theory studies. In addition, Molecular Docking studies were conducted to investigate the anti-cancer potential of synthesized heterocyclic compounds against caspase 3, NF-KAPPA-B and P53 protein. Molecular docking analysis demonstrated a potent interaction between 2,2'-(5,5'-(1,4-phenylene)bis(1H-tetrazole-5,1-diyl))bis-N-(2,4-dinitrophenyl) acetamides (6d) and TP53 and NF-KAPPA-B with binding energies of - 11.8 kJ/mol and - 10.9 kJ/mol for TP53 and NF-KAPPA-B, respectively. Similarly, 2,2'-(5,5'-(1,4-phenylene)bis(1H-tetrazole-5,1-diyl))bis-N-(2-chlorophenyl) acetamides (6f) exhibited a strong interaction with caspase-3 with binding energy of -10.0 kJ/mol, indicating their potential as therapeutic agents against these proteins. Furthermore, the findings of current study was further strengthen by 100 ns molecular dynamics (MD) simulations. Finally, theoretical studies of oxygen balance and nitrogen percentage suggest that these molecules can be utilized as energetic materials.

3.
Phys Chem Chem Phys ; 25(13): 9394-9403, 2023 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-36928872

RESUMO

Phenyl and pentafluorophenyl trifluorothioacetate, CF3C(O)SC6H5 and CF3C(O)SC6F5, were prepared by condensation of CF3C(O)Cl and the corresponding mercaptan RSH under vacuum conditions. The compounds were isolated and properly characterized by using infrared spectroscopy, UV-Vis, multinuclear NMR spectroscopy techniques and by mass spectrometry. The crystal structures have been determined for both CF3C(O)SC6H5 and according to the best of our knowledge the not yet reported in the literature CF3C(O)SC6F5 species. The conformational preferences of the three title species were also determined by means of FTIR spectroscopy. In the case of CF3C(O)OC6F5, the FTIR spectrum was also measured in an Ar-matrix and a subsequent photochemical study was performed. The main stable photoproduct found, beside CO, was the ether C6F5OCF3. Quantum-chemical calculations were used to determine the conformational preferences and complement the experimental structure parameters as well as to interpret the UV-Vis spectra determined for the three species under study. As a result of all these experimental determinations complemented with computational calculations, it can be affirmed that the title compounds present a single syn conformation in the analyzed phases (syn with respect to the CO double bond and the opposite C-chalcogen single bond). This finding reconfirms the syn conformational transferability found so far for both thioesters and esters, a result that is closely related to the properties of these families in biological processes.

4.
RSC Adv ; 12(20): 12710-12745, 2022 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-35496330

RESUMO

The interest in acyl thioureas has continually been escalating owing to their extensive applications in diverse fields, such as synthetic precursors of new heterocycles, pharmacological and materials science, and technology. These scaffolds exhibit a wide variety of biological activities such as antitumor, enzyme inhibitory, anti-bacterial, anti-fungal, and anti-malarial activities and find utilization as chemosensors, adhesives, flame retardants, thermal stabilizers, antioxidants, polymers and organocatalysts. In addition, the synthesis, and applications of coordination complexes of these ligands have also been overviewed. The current review is a continuation of our previous efforts in this area, focusing on the recent advancements during the period 2017 to present.

5.
J Chem Crystallogr ; 52(3): 345-358, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35291441

RESUMO

Hybrid moieties of ethynylated-thiourea, Th1 and Th2 have been synthesised via the addition reaction between ethynyl derivatives and 4-tert-butylbenzoyl isothiocyanate in acetone, and were characterised by selected spectroscopic methods (i.e., 1H and 13C NMR, UV-visible, FT-IR) and elemental analysis. Thermogravimetric analysis indicated that Th1 and Th2 were relatively stable up to ca. 210 °C. Single-crystal X-ray diffraction was used to identify the crystal structure of Th2 in which the centre of 1-acyl thiourea moiety (-C(O)NHC(S)NH) exhibits S conformation. The Hirshfeld surface analysis has allowed visualizing the crystal packing, which is characterised by the prolonged intermolecular N-H⋯O = C and N-H⋯S = C hydrogen-bonding interactions within Th2 molecule. Electrochemical data of both compounds correspondingly exhibit irreversible redox potential processes. Besides, frontier molecular orbitals and Natural Bond Orbital population analysis were computed at the B3LYP/6-31G (d, p) level of approximation, suggesting strong delocalization of the electronic density through a conjugated π-system involving the ethynyl-phenyl and thiourea groups. Graphical Abstract: Figure of molecular structure for acyl thiourea-ethynyl derivative. Two derivatives of acyl thiourea-ethynyl were synthesised and characterised by selected spectroscopic methods such as 1H and 13C NMR, UV-visible, FT-IR, elemental, thermal, electrochemical, X-ray diffraction, and density functional theory (DFT) calculation for molecular orbitals and natural bond orbital population analysis.

6.
Heliyon ; 7(9): e08042, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34611565

RESUMO

Solventless cyclocondensation of 2-aminothiophenol with thiourea afforded the benzo[d]oxazole-2-thiol (3a) capable of existing also in the tautomeric form benzo[d]oxazole-2(3H)-thione (3b). Acylation with methyl chloroacetate in dry ethanol in absence of any base or catalyst selectively afforded the S-substituted ester 2-(methoxycarbonylmethylthio)benzo[d]oxazole (4a) in preference to the corresponding N-substituted ester N-(methoxycarbonylmethyl)thioxobenzoxazole (4b). Quantum chemical calculations were conducted to determine the conformational landscape and NBO population analysis showed the strong electronic delocalization via resonance interactions on the 2-mercaptobenzaxazole group. The anomeric effect and the occurrence of a 1,4-S···O intramolecular interactions suggest the relevance of chalcogen bonding in the conformational preference. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (33.2%), H⋯O/O⋯H (19.9%) and H⋯C/C⋯H (17.8%) interactions. Hydrogen bonding and van der Waals interactions are the dominant interactions in the crystal packing. Computational chemistry indicates that in the crystal, the C-H⋯O hydrogen-bond energy is 44.8 kJ mol-1.

7.
J Mol Model ; 27(10): 296, 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34557964

RESUMO

The title compound is a new pyrazolone derivative which was synthesized starting from p-sulphophenyl-3-methyl-5-pyrazolone (1) by nitrosation at low temperature to afford the corresponding p-sulphophenyl-3-methyl-4-nitroso-5-pyrazolone which can exist both in nitroso (2a) and oxime tautomeric forms (2b). Reduction of the latter using zinc with hydrochloric acid furnished the 4-amino-p-sulphophenyl-3-methyl-5-pyrazolone (3). The diazotization of (3) under careful control of temperature and pH afforded the p-sulphophenyl-3-methyl-5-pyrazolone diazonium salt (4) which was re-crystallized from acidified ethanol to afford crystal suitable for X-ray studies. UV-visible spectrum and cyclic voltammetric studies were also carried out indicating λmax at 420 nm and HOMO-LUMMO energy gap was also calculated (Eg) of 2.95 eV. The molecular and crystal structures of the compound were clarified by single crystal X-ray diffraction indicated that it crystallizes as the sodium salt in the triclinic space group P -1, with the 4-azo-pyrazolone and the sulphophenyl groups being nearly coplanar. To get an insight to the intermolecular interactions in the crystal, a Hirshfeld surface analysis was also carried out.

8.
Acta Crystallogr E Crystallogr Commun ; 76(Pt 2): 148-154, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32071738

RESUMO

The reaction of N-phenyl-1-(pyridin-2-yl)methanimine with copper chloride dihydrate produced the title neutral complex, [CuCl2(C12H10N2)(H2O)]·H2O. The CuII ion is five-coordinated in a distorted square-pyramidal geometry, in which the two N atoms of the bidentate Schiff base, as well as one chloro and a water mol-ecule, form the irregular base of the pyramidal structure. Meanwhile, the apical chloride ligand inter-acts through a strong hydrogen bond with a water mol-ecule of crystallization. In the crystal, mol-ecules are arranged in pairs, forming a stacking of symmetrical cyclic dimers that inter-act in turn through strong hydrogen bonds between the chloride ligands and both the coordinated and the crystallization water mol-ecules. The mol-ecular and electronic structures of the complex were also studied in detail using EPR (continuous and pulsed), FT-IR and Raman spectroscopy, as well as magnetization measurements. Likewise, Hirshfeld surface analysis was used to investigate the inter-molecular inter-actions in the crystal packing.

9.
J Phys Chem A ; 123(31): 6674-6682, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31294991

RESUMO

Synchrotron-based total ion yield and photoelectron-photoion-coincidence spectra have been applied to investigate the electronic structure and the dissociative ionization of gaseous O,S-dimethyl xanthate, CH3OC(S)SCH3, in the shallow-core S 2p region. The spectral assignment and the electronic structure are interpreted in terms of the most stable synperiplanar conformer in the Cs symmetry point group. The use of tunable synchrotron radiation allows for a selective excitation of sulfur atoms at different photon energy values, including resonance transitions and ionization around the S 2p level. The fragmentation patterns show that the title molecule is well suited as a laboratory precursor of ionic species found in the interstellar medium, especially formyl and thioformyl cations, HCO+ and HCS+, respectively.

10.
Molecules ; 24(8)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999646

RESUMO

A series of symmetrical salicylaldehyde-bishydrazine azo molecules, 5a-5h, have been synthesized, characterized by 1H-NMR and 13C-NMR, and evaluated for their in vitro α-glucosidase and α-amylase inhibitory activities. All the synthesized compounds efficiently inhibited both enzymes. Compound 5g was the most potent derivative in the series, and powerfully inhibited both α-glucosidase and α-amylase. The IC50 of 5g against α-glucosidase was 0.35917 ± 0.0189 µM (standard acarbose IC50 = 6.109 ± 0.329 µM), and the IC50 value of 5g against α-amylase was 0.4379 ± 0.0423 µM (standard acarbose IC50 = 33.178 ± 2.392 µM). The Lineweaver-Burk plot indicated that compound 5g is a competitive inhibitor of α-glucosidase. The binding interactions of the most active analogues were confirmed through molecular docking studies. Docking studies showed that 5g interacts with the residues Trp690, Asp548, Arg425, and Glu426, which form hydrogen bonds to 5g with distances of 2.05, 2.20, 2.10 and 2.18 Å, respectively. All compounds showed high mutagenic and tumorigenic behaviors, and only 5e showed irritant properties. In addition, all the derivatives showed good antioxidant activities. The pharmacokinetic evaluation also revealed promising results.


Assuntos
Inibidores de Glicosídeo Hidrolases , Simulação de Acoplamento Molecular , alfa-Amilases/antagonistas & inibidores , alfa-Amilases/química , alfa-Glucosidases/química , Animais , Inibidores de Glicosídeo Hidrolases/síntese química , Inibidores de Glicosídeo Hidrolases/química , Estrutura Molecular , Suínos
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 210: 222-229, 2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30458390

RESUMO

Four related stannadithiane compounds containing different endocyclic functional groups -including ether (1), diether (2), lactone (3), and spirolactone (4)- were prepared. The conformational landscape has been fully determined for the 8-membered representative (compound 1) resulting in a distorted crown form with the butyl chains adopting an extended conformation. The infrared and Raman spectra of stannadithiane species have been measured and interpreted, aided by quantum chemical calculations and potential energy surface analysis. Special attention has been devoted to the analysis of the vibrational features of the heterocyclic moieties. The characteristic νas(SnS) and νs(SnS) stretching modes of the SnS2endo-cyclic group were clearly observed in the Raman spectra at around 340 and 315 cm-1, respectively. The exo-cyclic ν(SnC) stretching modes were found near 590 and 565 cm-1 for the antisymmetric and symmetric motions, respectively. Thermal behavior for compounds 2-4 has been determined by thermogravimetric methods.

12.
J Phys Chem A ; 122(51): 9842-9850, 2018 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-30466259

RESUMO

The photoexcitation, photoionization, and photofragmentation of gaseous CF3CF2C(O)OH were studied by means of synchrotron radiation in the valence and inner energy regions. Photofragmentation events were detected from 11.7 eV through formation of COH+, C2F4+, and the parent species M+. Because the vertical ionization potential has been reported at 11.94 eV, the starting energy used in this study, 11.7 eV, falls just inside of the tail of the ionization band in the photoelectron spectra. Information from the total ion yield spectra around the C 1s, O 1s, and F 1s ionization potentials allows the energies at which different resonance transitions take place in the molecule to be determined. These transitions have been assigned by comparison with the results of the analysis of similar compounds. In the inner energy region, both kinetic energy release (KER) values and the slope and shape of double coincidence islands obtained from photoelectron-photoion-photoion coincidence (PEPIPICO) spectra allow different photofragmentation mechanisms to be elucidated.

13.
Eur J Med Chem ; 156: 461-478, 2018 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-30015078

RESUMO

In the present work we report the synthesis of new aryl pyrazole derivatives using 1,3-dicarbonyl motifs. The reaction was proceeded by the cyclization of pentane-2,4-dione (1a), 3-chloropentane-2,4-dione (1b) or ethyl 3-oxobutanoate (1c) with different aryl hydrazines. The products, which can be regarded as 1H-pyrazol-1-yl-one analogues (3a-f, 3g-o, 4a-c, 5a-b) and represent drug like molecules along with well-developed structure-activity relationships, were obtained in good to excellent yield. The structures of synthesized compounds were charcterized on the basis of FT-IR, 1H NMR, 13C NMR and mass spectroscopic data. Considering alkaline phosphatases (APs), nucleotide pyrophosphatases/phosphodiesterases (NPPs) and nucleoside triphosphate diphosphohydrolase as the molecular targets, the effects of these synthesized compounds were investigated on different isozymes of APs, NPPs and NTPDases. The data revealed that the synthesized compounds inhibited both enzymes but most of them inhibited tissue non-specific alkaline phosphatase (TNAP) more selectively. The antitumor activity results indicated that the synthesized derivatives have strong inhibitory effects on the growth of selected cell lines from different tissues such as breast, bone marrow and cervix (MCF-7, K-562 and Hela) but with varying intensities. Moreover the binding mode of interactions were explained on the basis of molecular docking and in-silico studies.


Assuntos
Fosfatase Alcalina/antagonistas & inibidores , Antineoplásicos/farmacologia , Inibidores Enzimáticos/farmacologia , Pirazóis/farmacologia , Pirofosfatases/antagonistas & inibidores , Fosfatase Alcalina/metabolismo , Antineoplásicos/química , Linhagem Celular Tumoral , Inibidores Enzimáticos/química , Humanos , Simulação de Acoplamento Molecular , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Inibidores de Fosfodiesterase/química , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/metabolismo , Pirazóis/química , Pirofosfatases/metabolismo , Relação Estrutura-Atividade
14.
Bioorg Chem ; 79: 293-300, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29793142

RESUMO

Aryl pyrazoles are well recognized class of heterocyclic compounds found in several commercially available drugs. Owing to their significance in medicinal chemistry, in this current account we have synthesized a series of suitably substituted aryl pyrazole by employing Suzuki cross-coupling reaction. All compounds were evaluated for inhibition of mushroom tyrosinase enzyme both in vitro and in silico. Compound 3f (IC50 = 1.568 ±â€¯0.01 µM) showed relatively better potential compared to reference kojic acid (IC50 = 16.051 ±â€¯1.27 µM). A comparative docking studies showed that compound 3f have maximum binding affinity against mushroom tyrosinase (PDBID: 2Y9X) with binding energy value (-6.90 kcal/mol) as compared to Kojic acid. The 4-methoxy group in compound 3f shows 100% interaction with Cu. Compound 3f displayed hydrogen binding interaction with His61 and His94 at distance of 1.71 and 1.74 Šwhich might be responsible for higher activity compared to Kojic acid.


Assuntos
Agaricales/enzimologia , Inibidores Enzimáticos/farmacologia , Simulação de Acoplamento Molecular , Monofenol Mono-Oxigenase/antagonistas & inibidores , Pirazóis/farmacologia , Pironas/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Cinética , Estrutura Molecular , Monofenol Mono-Oxigenase/metabolismo , Pirazóis/síntese química , Pirazóis/química , Pironas/química , Relação Estrutura-Atividade
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 198: 290-296, 2018 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-29558728

RESUMO

Two closely related hybrid species containing both, thiazolyl and coumarin groups, were synthesized by using two different one-pot procedures from a common precursor. The reaction of α-bromoacetylcoumarin with thioacetamide in methanol furnished 3­(2­methylthiazol­4­yl)­2H­chromen­2­one (2), whereas refluxing α­bromoacetylcoumarin with potassium thiocyanate in ethanol afforded 3­(2­ethoxythiazol­4­yl)­2H­chromen­2­one (3). Both derivatives were fully characterized by spectroscopic methods, elemental analysis and X-ray diffraction studies. Intramolecular C4H⋯N and C5'H⋯OC hydrogen bonds between the heterocycles determine the conformational behavior. The co-planarity of the coumarin and thiazolyl rings favors the occurrence of two remote orbital interactions involving the oxygen and nitrogen lone pairs and the corresponding σ*CH electron acceptor, as demonstrated by Natural Bond Orbital population analysis. The 2-substitution of the thiazol­4­yl group has little effect on the molecular structures but causes significant differences in the crystal packing of the two compounds.

16.
J Phys Chem A ; 121(48): 9201-9210, 2017 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-29096437

RESUMO

Both photoelectron spectroscopy (PES) data and PhotoElectron-PhotoIon-Coincidence (PEPICO) spectra obtained from a synchrotron facility have been used to examine the electronic structure and the dissociative ionization of halomethyl thiocyantes in the valence and shallow-core S 2p and Cl 2p regions. Two simple and closely related molecules, namely, CCl3SCN and CCl2FSCN, have been analyzed to assess the role of halogen substitution in the electronic properties of thiocyanates. The assignment of the He(I) photoelectron spectra has been achieved with the help of quantum chemical calculations at the outer-valence Green's function (OVGF) level of approximation. The first ionization energies observed at 10.55 and 10.78 eV for CCl3SCN and CCl2FSCN, respectively, are assigned to ionization processes from the sulfur lone pair orbital [n(S)]. When these molecules are compared with CX3SCN (X = H, Cl, F) species, a linear relationship between the vertical first ionization energy and electronegativity of CX3 group is observed. Irradiation of CCl3SCN and CCl2FSCN with photons in the valence energy regions leads to the formation of CCl2X+ and CClXSCN+ ions (X = Cl or F). Additionally, the achievement of the fragmentation patterns and the total ion yield spectra obtained from the PEPICO data in the S 2p and Cl 2p regions and several dissociation channels can be inferred for the core-excited species by using the triple coincidence PEPIPICO (PhotoElectron-PhotoIon-PhotoIon-Coincidence) spectra.

17.
Artigo em Inglês | MEDLINE | ID: mdl-28063310

RESUMO

1-Acyl thioureas [R1C(O)NHC(S)NR2R3] are shown to display conformational flexibility depending on the degree of substitution at the nitrogen atom. The conformational landscape and structural features for two closely related thioureas having R1=2-furoyl have been studied. The un-substituted 2-furoyl thiourea (I) and its dimethyl analogue, i.e. 1-(2-furoyl)-3,3-dimethyl thiourea (II), have been synthesized and fully characterized by spectroscopic (FT-IR, 1H and 13C NMR) and elemental analysis. According to single crystal X-ray diffraction analysis, compounds I and II crystallize in the monoclinic space group P21/c. In the compound I, the trans-cis geometry of the almost planar thiourea unit is stabilized by intramolecular NH⋯OC hydrogen bond between the H atom of the cis thioamide and the carbonyl O atom. In compound II, however, the acyl thiourea group is non-planar, in good agreement with the potential energy curve computed at the B3LYP/6-31+G(d,p) level of approximation. Centrosymmetric dimers generated by intermolecular NH⋯SC hydrogen bond forming R22(8) motif are present in the crystals. Intermolecular interactions have been rationalized in terms of topological partitions of the electron distributions and Hirshfeld surface analysis, which showed the occurrence of S⋯H, O⋯H and H⋯H contacts that display an important role to crystal packing stabilization of both thiourea derivatives.

18.
Artigo em Inglês | MEDLINE | ID: mdl-27070529

RESUMO

The title paper [1] reports a study on the spectroscopic and physicochemical properties of 1-(5-methyl- [1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol (MTPN) based on experimental and theoretical data. The latter ones are based on the computed molecular structure for a rather unusual conformer. Here, after a careful analysis of the conformational space of MTPN, the most stable conformation was determined for the molecule isolated in a vacuum, which results to be 21.9kJ/mol more stable than the conformer reported previously. Our study also includes the closely related species 1-(5-trifluoromethyl- [1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol (FMTPN). An intramolecular OH⋯N hydrogen bond determines the conformational behavior of the [1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol group as demonstrated by Natural Bond Orbital population analysis.


Assuntos
Ligação de Hidrogênio , Modelos Moleculares , Conformação Molecular , Espectroscopia de Infravermelho com Transformada de Fourier , Vibração
19.
Chemphyschem ; 17(10): 1463-7, 2016 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-26865044

RESUMO

Trichloromethyl thiocyanate, CCl3 SCN, was structurally studied in both the gas and crystal phases by means of gas electron diffraction (GED) and single-crystal X-ray diffraction (XRD), respectively. Both experimental studies and quantum chemical calculations indicate a staggered orientation of the CCl3 group relative to the SCN group. This conclusion is supported by the similarity of the C-SCN bond length to that of the anti-structure of CH2 ClSCN (Berrueta Martínez et al. Phys. Chem. Chem. Phys. 2015, 17, 15805-15812). Bond lengths and angles are similar for gas and crystal CCl3 SCN structures; however, the crystal structure presents different intermolecular interactions. These include halogen and chalcogen type interactions, the geometry of which was studied. Characteristic C-Y⋅⋅⋅N angles (Y=Cl or S) close to 180° provide evidence for typical σ-hole interactions along the halogen/chalcogen-carbon bond in N⋅⋅⋅Cl and N⋅⋅⋅S, intermolecular units.

20.
Spectrochim Acta A Mol Biomol Spectrosc ; 157: 138-145, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26761413

RESUMO

The 2-(phenyl-hydrazono)-succinic acid dimethyl ester compound was synthesized by reacting phenylhydrazine with dimethylacetylene dicarboxylate at room temperature and characterized by elemental analysis, infrared, Raman, (1)H and (13)C NMR spectroscopies and mass spectrometry. Its solid state structure was determined by X-ray diffraction methods. The X-ray structure determination corroborates that the molecule is present in the crystal as the hydrazone tautomer, probably favored by a strong intramolecular N-H···O=C hydrogen bond occurring between the carbonyl (-C=O) and the hydrazone -C=N-NH- groups. A substantial fragment of the molecular skeleton is planar due to an extended π-bonding delocalization. The topological analysis of the electron densities (Atom in Molecule, AIM) allows characterization of intramolecular N-H···O interaction, that can be classified as a resonant assisted hydrogen bond (RAHB). Moreover, the Natural Bond Orbital population analysis confirms that a strong hyperconjugative lpO1→σ*(N2-H) remote interaction between the C2=O1 and N2-H groups takes place. Periodic system electron density and topological analysis have been applied to characterize the intermolecular interactions in the crystal. Weak intermolecular interactions determine the crystal packing, and the prevalence of non-directional dispersive contributions are inferred on topological grounds. The IR spectrum of the crystalline compound was investigated by means of density functional theory calculations carried out with periodic boundary conditions on the crystal, showing excellent agreement between theory and the experiments. The vibrational assignment is complemented with the analysis of the Raman spectrum.

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