Normal coordinate analysis and crystal structure of N,N-dimethyl-N'-(2-chloro-benzoyl)thiourea

Understanding the conformational changes and molecular structure of furoyl thioureas upon substitution

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.

Synthesis, X-ray crystal structure, thermal behavior and spectroscopic analysis of 1-(1-naphthoyl)-3-(halo-phenyl)-thioureas complemented with quantum chemical calculations

Two novel 1-(1-naphthoyl)-3-(halo-phenyl) substituted thioureas, namely 1-(1-naphthoyl)-3-(2,4-di-fluoro-phenyl)-thiourea (1) and 1-(1-naphthoyl)-3-(3-chloro-4-fluoro-phenyl)-thiourea (2), were synthesized and fully characterized. The X-ray crystal and molecular structures have been determined resulting in a planar acylthiourea group, with the C=O and C=S adopting a pseudo-antiperiplanar conformation. An intramolecular N-H⋯O=C hydrogen bond occurs between the thioamide and carbonyl groups. The crystal packing of both compounds is characterized by extended intermolecular N-H⋯S=C and N-H⋯O=C hydrogen-bonding interactions involving the acylthiourea moiety. Compound 2 is further stabilized by π-stacking between adjacent naphthalene and phenyl rings. The thermal behavior, as well as the vibrational properties, studied by infrared and Raman spectroscopy data complemented by quantum chemical calculations at the B3PW91/6-311++G(d,p) support the formation of these intra- and intermolecular hydrogen bonds. Furthermore, the UV-Vis spectrum is interpreted in terms of TD-DFT quantum chemical calculations with the shapes of the simulated absorption spectra in good accordance with the experimental data.

Intra- and intermolecular hydrogen bonding and conformation in 1-acyl thioureas: an experimental and theoretical approach on 1-(2-chlorobenzoyl)thiourea

The vibrational analysis (FT-IR and FT-Raman) for the new 1-(2-chlorobenzoyl)thiourea species suggests that strong intramolecular interactions affect the conformational properties. The X-ray structure determination corroborates that an intramolecular N-H⋯OC hydrogen bond occurs between the carbonyl (-CO) and thioamide (-NH2) groups. Moreover, periodic system electron density and topological analysis have been applied to characterize the intermolecular interactions in the crystal. Extended N-H⋯SC hydrogen-bonding networks between both the thioamide (N-H) and carbamide (NH2) groups and the thiocarbonyl bond (CS) determine the crystal packing. The Natural Bond Orbital (NBO) population analysis demonstrates that strong hyperconjugative remote interactions are responsible for both, intra and intermolecular interactions. The Atom in Molecule (AIM) results also show that the N-H⋯Cl intramolecular hydrogen bond between the 2-Cl-phenyl ring and the amide group characterized in the free molecule changes to an N⋯Cl interaction as a consequence of crystal packing.

Palladium(II) complexes of OS donor N-(di(butyl/phenyl)carbamothioyl)benzamide and their antiamoebic activity

Two promising palladium(II) compounds of general formula, cis-[Pd(L-O,S)2] [where HL-O,S = N-(di(butyl/phenyl)carbamothioyl)benzamide] as metal based antiamoebic drug candidates, have been synthesized. Both complexes are characterized in the solid state by FT-IR spectroscopy, TGA and single crystal X-ray study, as well as in solution by other spectroscopic techniques such as (1)H and (13)C NMR, and UV-visible. All these studies confirm the coordination of ligands through oxygen and sulphur atoms upon thioenolization induced delocalization. Complexes adopt cis-configuration in the solid state. Both the complexes and their respective ligands were screened in vitro for antiamoebic activity against HM1:1MSS strain of Entamoeba histolytica by microdilution method and cell viability in response to drugs was checked by using MTT assay. The IC50 values in the range 0.30-0.80 μM for ligands as well as complexes compared to 1.40 for metronidazole along with their similar inhibitory effect on cell viability of HEK293 cells like metronidazole make them promising future antiamoebic drugs.

Synthesis and Characterization of Novel Thiourea Derivatives and Their Nickel and Copper Complexes

New benzoyl thiourea derivatives and their nickel and copper complexes were synthesized. The structure of the synthesized compounds were confirmed by elemental analysis, FT-IR, and1H NMR techniques. Four of the synthesized compounds are analyzed by X-ray single crystal diffraction technique. WhereasN,N-dimethyl-N′-(4-fluorobenzoyl)thiourea,N,N-diethyl-N′-(4-fluorobenzoyl)thiourea, andN,N-di-n-butyl-N′-(4-fluorobenzoyl) thiourea crystallize in the monoclinic system,bis(N,N-di-n-propyl-N′-(4-fluorobenzoyl)thioureato) nickel(II) complex crystallizes in the triclinic system. These ligand molecules form dimers through strong intermolecular hydrogen bonds such as N–H⋯S, C–H⋯O, and N–H⋯O. Moreover, there are different types of intramolecular interactions in the crystal structures.Bis(N,N-dimethyl-N′-(4-fluorobenzoyl)thioureato) nickel(II) complex has a nearly square-planar coordination. The distance of nickel atom from the best plane through the coordination sphere is 0.029 Å.

An Efficient One-Pot Synthesis of bis-1-(aroyl)-3-(aryl)thiourea

A three-component and one-pot reaction between 2,6-diaminopyridine or 1,2-diaminobenzene and ammonium thiocyanate with the subsequent addition of an aroyl chloride afforded the bis-1-(aroyl)-3-(aryl)thiourea in excellent yields. It was important to make the thiocyanate derivatives first and then to use those to prepare the thiourea derivatives.

1-Benzoyl-3,3-bis-(2-methyl-prop-yl)thio-urea

The title compound, C₁₆H₂₄N₂OS, is twisted about the central N(H)—C bond with the C—N—C—S torsion angle being 119.6 (3)°. The carbonyl O and thione S atoms are directed to opposite sides of the mol­ecule, a conformation that allows for the formation of a linear supra­molecular chain comprising alternating eight-membered {⋯HNCS}₂ and 14-membered {⋯HCNCNCO}₂ synthons.

The molecular structure and vibrational spectra of N-(2,2-diphenylacetyl)-N'-(naphthalen-1yl)-thiourea by Hartree-Fock and density functional methods

N-(2,2-Diphenylacetyl)-N'-(naphthalen-1yl)-thiourea (PANT) has been synthesized and characterized by elemental analysis, IR spectroscopy and (1)H NMR spectroscopy. The crystal and molecular structure of the title compound has been determined from single crystal X-ray diffraction data. It crystallizes in the triclinic space group P-1, Z=2 with a=10.284(2)A, b=10.790(2)A, c=11.305(2)A, alpha=64.92(3) degrees , beta=89.88(3) degrees , gamma=62.99(3) degrees , V=983.7(3)A(3) and D(calc)=1.339Mg/m(3). The molecular structure, vibrational frequencies and infrared intensities of PANT were calculated by the Hartree-Fock and density functional theory methods (BLYP and B3LYP) using the 6-31G* basis set. The calculated geometric parameters were compared to the corresponding X-ray structure of the title compound. We obtained 22 stable conformers for the title compound; however Conformer 1 is approximately 9.53kcal/mol more stable than Conformer 22. The comparison of the theoretical and experimental geometry of the title compound shows that the X-ray parameters fairly well reproduce the geometry of Conformer 17. The harmonic vibrations computed for this compound by the B3LYP/6-31G* method are in good agreement with the observed IR spectral data. Theoretical vibrational spectra of the title compound were interpreted by means of PEDs using the VEDA 4 program. A general better performance of the investigated methods was calculated by PAVF 1.0 program.

Synthesis and characterization of N-(Arylcarbamothioyl)-cyclohexanecarboxamide derivatives: the crystal structure of N-(naphthalen-1-ylcarbamothioyl)cyclohexanecarboxamide

A number of N-(arylcarbamothioyl)cyclohexanecarboxamide derivatives (aryl substituents: phenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, o-tolyl, p-tolyl, 3-methoxyphenyl, 4-methoxyphenyl and naphthalen-1yl) have been synthesized. The compounds obtained were characterized by elemental analyses, IR spectroscopy and ¹H-NMR spectroscopy. N-(naphthalen-1-ylcarbamothioyl)cyclohexanecarboxamide, H₂L⁹, was also characterized by a single crystal X-ray diffraction study. This compound, C₁₈H₂₀N₂OS, crystallizes in the triclinic space group Pī, with Z = 2, and unit cell parameters a = 6.9921(14) Å, b = 11.002(2) Å, c = 12.381(3) Å, α = 113.28(3)°, β = 99.38(3)°, and γ = 101.85(3)°. The cyclohexane ring adopts a chair conformation. The molecular conformation of the compound is stabilized by an intramolecular (N2-H2•••O1) hydrogen bond which forms a pseudo-six-membered ring.

4-Bromo-N-(di-n-propyl-carbamothioyl)-benzamide

The synthesis of the title compound, C₁₄H₁₉BrN₂OS, involves the reaction of 4-bromo­benzoyl chloride with potassium thio­cyanate in acetone followed by condensation of the resulting 4-bromo­benzoyl isothio­cyanate with di-n-propyl­amine. Typical thio­urea carbonyl and thio­carbonyl double bonds, as well as shortened C—N bonds, are observed in the title compound. The short C—N bond lengths in the centre of the mol­ecule reveal the effects of resonance in this part of the mol­ecule. The asymmetric unit of the title compound contains two crystallographically independent mol­ecules, A and B. There is very little difference between the bond lengths and angles of these mol­ecules. In mol­ecule B, one di-n-propyl group is twisted in a −anti­periplanar conformation with C—C—C—H = −179.1 (3)° and the other adopts a −synclinal conformation with C—C—C—H = −56.7 (4)°; in mol­ecule A the two di-n-propyl groups are twisted in + and −anti­periplanar conformations, with C—C—C—H = −179.9 (3) and 178.2 (3)°, respectively. In the crystal, the mol­ecules are linked into dimeric pairs via pairs of N—H⋯S hydrogen bonds.

4-Bromo-N-(diethyl-carbamothio-yl)-benzamide

The synthesis of the title compound, C₁₂H₁₅BrN₂OS, involves the reaction of 4-bromo­benzoyl chloride with potassium thio­cyanate in dry acetone, followed by condensation of 4-bromo­benzoyl isothio­cyanate with diethyl­amine. The carbonyl and thio­carbonyl bond lengths indicate that these correspond to double bonds. The short C—N bond lengths reveal the effects of resonance in this part of the mol­ecule. The conformation of the mol­ecule with respect to the thio­carbonyl and carbonyl units is twisted, with torsion angles of −5.7 (3) and 87.2 (2)°. The N atom of the diethyl­amine group is sp²-hybridized: the sum of the angles around the N atom is 359.97 (14)°. The two diethyl groups are twisted in + and − anti­periplanar conformations with angles of −179.89 and 179.92°. In the crystal structure, the mol­ecules form infinite chains via an inter­molecular N—H⋯O inter­action.

Antimicrobial activity of some thiourea derivatives and their nickel and copper complexes

Five thiourea derivative ligands and their Ni(2+) and Cu(2+) complexes have been synthesized. The compounds were screened for their in vitro anti-bacterial activity using Gram-positive bacteria (two different standard strains of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pyogenes, Bacillus cereus) and Gram-negative bacteria (Esherichia coli, Pseudomonas aeruginosa, Enterobacter cloacae, Proteus vulgaris, Enterobacter aerogenes) and in vitro anti-yeast activity (Candida albicans, Candida krusei, Candida glabrata, Candida tropicalis, Candida parapsilosis). The minimum inhibitory concentration was determined for all ligands and their complexes. In vitro anti-yeast activity of both ligands and their metal complexes is greater than their in vitro anti-bacterial activity. The effect of the structure of the investigated compounds on the antimicrobial activity is discussed.

4-Chloro-N-[N-(6-methyl-2-pyrid-yl)car-bamo-thio-yl]benzamide

In the title compound, C(14)H(12)ClN(3)OS, the short exocyclic N-C bond lengths indicate resonance in the thiourea part of the mol-ecule. The title compound is stabilized by an intra-molecular N-H⋯N hydrogen bond, which results in the formation of a six-membered ring. In addition, it shows a synperiplanar conformation between the thio-carbonyl group and the pyridine group. Inter-molecular N-H⋯S and C-H⋯O inter-actions are also present.

The molecular structure and vibrational spectra of 2-chloro-N-(diethylcarbamothioyl)benzamide by Hartree-Fock and density functional methods

2-Chloro-N-(diethylcarbamothioyl)benzamide (C(12)H(15)ClN(2)OS) has been synthesized and characterized by elemental analysis and IR spectroscopy. The crystal and molecular structure of the title compound has been determined from single crystal X-ray diffraction data. It crystallizes in the orthorhombic space group Pbca, Z=8 with a=9.581(3)A, b=9.992(3)A, c=26.640(8)A, V=2550.5(13)A(3) and D(calc)=1.410 Mg/m(3). The molecular geometry and vibrational frequencies of 2-chloro-N-(diethylcarbamothioyl)benzamide in the ground state have been calculated using the Hartree-Fock and density functional using Becke's three-parameter hybrid method with the Lee, Yang and Parr correlation functional (B3LYP) methods with 3-21G and 6-31G(d) basis sets. The calculated geometric parameters were compared to the corresponding X-ray structure of the title compound. The raw B3LYP frequencies approximate the experimental data much better than the results of Hartree-Fock. The scaled B3LYP/6-31G(d) results were more reliable than those obtained using the B3LYP/3-21G method with the mean absolute deviation about 13.7 cm(-1). On the basis of the comparison between calculated and experimental results, assignments of fundamental vibrational modes were examined.