The crystal and molecular structures of the N,N’-diisopropylbutyramide (DIPIBA) and N,N-dicyclohexylacetamide (DCA) complexes [Th(NCS) 4(DIPIBA) 3] and [Th(NCS) 2Cl 2(DCA) 3

Abstract

The X-ray crystal structures of [Th(NCS) 4(DIPIBA) 3] ( 1) [DIPIBA Me 2CH CON(CHMe 2) 2] and [Th(NCS) 2Cl 2(DCA) 3]( 2) [DCA MeCON(cycloC 6H 11) 2] have been determined from three-dimensional X-ray diffraction data. The different steric constraints of the ligand are not sufficient for different coordination geometries. In 1 and 2 the coordination polyhedron about the seven-coordinate thorium atom is a pentagonal bipyramid geometry which is becoming rather common for thorium(IV) compounds. In these compounds two chlorine ( 2) and two thiocyanate ( 1) anions are in axial positions with a significant shortening of the axial Th—NCS bonds with respect to the equatorial ones, while in the equatorial plane a neutral ligand lies between two anionic ligands, the remaining coordination positions being occupied by two other neutral ligands. The average bonding distances are Th O = 2.34(1)Å, Th N ax = 2.42(1) and Th N eq = 2.46(1)Åin 1, and Th O = 2.357(5), Th N eq = 2.479(6) and Th Cl ax = 2.695(3)Åin 2.