Synthesis, X-Ray crystallography and HF/DFT analysis of N(diethylcarbamothioyl) furan-2-carboxamide, analyzed by experimental and theoretical methods

Abstract

Reaction of freshly prepared furanoyl isothiocyanate (2) with diethyl amine afforded N-(diethylcarbamothioyl)furan-2-carboxamide (3) in an excellent yield and purity. The furanoyl isothiocyanate (2) was, in turn, obtained by a reaction between furanoyl chloride (1) with potassium thiocyanate. The structure of 3 was deduced by spectroscopic data and elemental analysis and corroborated by single crystal X-ray crystallography. The crystal data indicated that the furan ring is almost coplanar with the aminocarbamothioyl moiety in 3, facilitating an intra-molecular hydrogen bond between oxygen of the furan ring and NH of thiourea group. Detailed analysis of intermolecular interactions in the crystal was performed by applying the Hirshfeld surface method, indicating that crystal packing is facilitated (up to 55%) by an intermolecular hydrogen bonding between NH on one molecule and the carbonyl oxygen on the other. Finally, quantum chemical analysis of 3 was conducted using ab initio (6-311+G**) and density functional (B3LYP/6-311+G**) models for determination of electrochemical properties of the title compound. Both the Hartree Fock (HF) and density functional theory (DFT) predicted identical 3D structure for 3, which matches closely with the X-Ray Crystal structure. The NBO analyses, molecular electrostatic potential (MEP) and total density of states (DOS) are accomplished along with other the electrochemical properties of 3 including ionization potential (I), electron affinity (A), chemical hardness (η), electronic chemical potential (μ) and electrophilicity (ω).