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 Nsingle bondH ⋯ Odouble bondC 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 N — H ⋯ O = C 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.Instituto de Física La PlataCentro de Química Inorgánic

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 N[sbnd]H ⋯ O[dbnd]C 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 N[sbnd]H ⋯ S[dbnd]C hydrogen bond forming R2 2(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.Fil: Ramos Cairo, Raúl. Universidad de La Habana; CubaFil: Plutín Stevens, Ana María. Universidad de La Habana; CubaFil: Donizeth de Oliveira, Tamires. Universidade Federal do São Carlos; BrasilFil: Batista, Alzir A.. Universidade Federal do São Carlos; BrasilFil: Castellano, Eduardo E.. Universidad de La Habana; CubaFil: Duque, Julio. Universidad de La Habana; CubaFil: Soria, Delia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Fantoni, Adolfo Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Corrêa, Rodrigo S.. Universidade Federal de Ouro Preto; BrasilFil: Erben, Mauricio Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentin

Dynamics of Formation of Binuclear Metal Complexes: A New Cu(I) Compound with N-(2-thiophenecarbonyl)-N’-(3-Cl, 4-F-phenyl)thiourea as Ligand

Herein we report the synthesis and characterization of a new copper(I) complex with triphenylphosphine (PPh3) and N-(2-thiophenecarbonyl)-N’-(3-Cl, 4-F-phenyl)thiourea (HL), as ligands. The complex was characterized by vibrational (FTIR and FT-Raman) and multinuclear (1H, 13C {1H}, 31P{1H}) NMR spectroscopies. The crystalline structure of the complex was determined by single-crystal X-ray diffraction, confirming that a neutral binuclear compound, identified as [Cu(PPh3)(L-κ2-N,μ-S)]2, was obtained. The anionic thiourea ligand coordinates to the metal through the sulfur and nitrogen atoms in an unusual bidentate κ2-N,μ-S coordination mode. The complex is a dimer sited on a crystallographic center of symmetry. Each Cu2(μ-S)2 cation bridges trough the sulfur atoms of two symmetry related thiourea moieties and is also coordinated to the nitrogen atom of the thiourea ligand and the phosphorus atom from PPh3 co-ligand, forming a slightly distorted tetrahedral geometry. An intramolecular N−H⋅⋅⋅O=C hydrogen bond is observed in the anionic ligand, forming a six-membered ring that stabilizes the N−H thioamide group. Hirshfeld surface analysis shows that the molecules are connected by weak intermolecular contacts C⋅⋅⋅C, H⋅⋅⋅C and H⋅⋅⋅H which add to the stability of the crystalline packing. The in vitro cytotoxicity study of the complex indicates that it is more active against human lung carcinoma cells (A549), when compared to the free ligand.Fil: Ramos Cairo, Raúl. Universidad de La Habana; CubaFil: María Plutín, Ana. Universidad de La Habana; CubaFil: Oscar Mocelo Castell, Raúl. Universidad de La Habana; CubaFil: Castellano, Eduardo Ernesto. Universidade de Sao Paulo; BrasilFil: Corrêa, Rodrigo S.. Universidade Federal de Ouro Preto; BrasilFil: Nossa González, Diana Lisseth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Erben, Mauricio Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Regina Cominetti, Marcia. Universidade Federal do São Carlos; BrasilFil: Morais Leite, Celisnolia. Universidade Federal do São Carlos; BrasilFil: Donizeth de Oliveira, Tamires. Universidade Federal do São Carlos; BrasilFil: Batista, Alzir A.. Universidade Federal do São Carlos; Brasi