title: Synthesis, X-ray crystal structure, thermal behavior and spectroscopic analysis of 1-(1-naphthoyl)-3-(halo-phenyl)-thioureas complemented with quantum chemical calculations.
abstract: 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.
authors.affiliation: Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan. Electronic address: aamersaeed@yahoo.com.
authors.forename: Aamer
authors.initials: A
authors.lastname: Saeed
authors.affiliation: Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan.
authors.forename: Saba
authors.initials: S
authors.lastname: Ashraf
authors.affiliation: Bio-21 Institute, School of Chemistry, University of Melbourne, Parkville, Victoria 3052, Australia.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
authors.affiliation: CEQUINOR (UNLP, CONICET-CCT La Plata), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 962, 1900 La Plata, Argentina.
authors.forename: Delia B
authors.initials: DB
authors.lastname: Soria
authors.affiliation: CEQUINOR (UNLP, CONICET-CCT La Plata), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 962, 1900 La Plata, Argentina.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Franca
authors.affiliation: CEQUINOR (UNLP, CONICET-CCT La Plata), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 962, 1900 La Plata, Argentina. Electronic address: erben@quimica.unlp.edu.ar.
authors.forename: Mauricio F
authors.initials: MF
authors.lastname: Erben
keywords: Quantum chemical calculations; Thermogravimetry; Thiourea; Vibrational spectroscopy; X-ray crystal structure