The Role of Substituents in the Molecular and Crystal Structure of 1-(Adamantane-1-carbonyl)-3-(mono)- and 3,3-(di) Substituted) Thioureas

SAEED, AAMER; FLORKE, ULRICH; ERBEN, MAURICIO FEDERICO

JOURNAL OF MOLECULAR STRUCTURE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 1065 p. 150 - 159

0022-2860

Three novel 1-(adamantane-1-carbonyl) thioureas were synthesized by the reaction of adamantyl isothiocyante with corresponding amines and fully characterized by spectroscopy methods. Two isomeric species, i.e. 1-(adamantane-1-carbonyl)-3-(3-nitrophenyl)thiourea (1) and 1-(adamantane-1-carbonyl)- 3-(4-nitrophenyl)thiourea (2), are structurally characterized and a third related compound, namely 1-(adamantane-1-carbonyl)-3,3-(methyl-phenyl)thiourea (3) has been also included for assessing the role of the nitrogen substitution on the structural properties. As determined by X-ray analysis, compounds 1 and 2 exhibit the S conformation with the C=O and C=S double bonds in a pseudo-antiperiplanar orientation, whereas the U form is found for compound 3. These conformational features are mainly dictated by the substitution degree on the thiourea core and the ability of forming an intra-molecular N-H···O=C hydrogen bond for mono-substituted analogues 1 and 2. These dissimilar interactions affect the vibrational properties, which have been determined by infrared and Raman spectroscopies and quantumchemical calculations at the B3LYP/6-311++G** level of approximation.