Crystal structures and Hirshfeld surface analysis of (cat)2[FeIII(η3-dipic)(NCS)3] and (cat)[FeIII(η3-dipic)(H2O)(NCS)2] (dipic = dipicolinate)

Abstract

Crystal and molecular structures of black (cat)2[FeIII(η3-dipic)(NCS)3] (cat = C9H7NH; C10H9NH); (HNC10H8NH)[FeIII(dipic)(NCS)3], and (C6H7NH)[FeIII(η3-dipic)(H2O)(NCS)2] (dipic pyridine-2,6-dicarboxylate (−2); C9H7NH = quinolinium; C10H9NH = 3-methylisoquinolinium; HNC10H8NH = 4,4-bipyridinium; C6H7NH = 2-picolinium) were determinated. These complexes crystallized in monoclinic crystal class. Each Fe(III) atom is six coordinated. The octahedron is build up unsymmetrically, one half side is creates by terdentate dipic–1O,2N,3O ligand and the other half by three monodentate (NCS)3 or (NCS)2(H2O) donor ligands. The terdentate dipic–1O,2N,3O ligand forms a pair of five-membered metallocyclic rings with the common central 2N atom of pyridine (1OC22NC23O) with the mean value of O–Fe–N bite angles of 75.5°. The mean value of trans1O–Fe–3O bond angles is 150.8° in complexes with an inner coordination spheres FeO2N4 and FeO3N3. The mean value of sum of all three ((Fe–1O) + (Fe–2N) + (Fe–3O)) bond distances is 6.217 Å (FeO2N4) and 6.183 Å (FeO3N3). The opposite side in FeO2N4 is created by three monodentate NCS groups with the sum of Fe–N(x3) bond distances of 6.050 Å and in the FeO3N3 two NCS groups with water create opposite side with the sum of (Fe–N(x2) + Fe–O) bond distances of 6.183 Å. One polymorph of complex (C10H9NH)2[FeIII(dipic)(NCS)3] contains two crystallographically independent molecules differ mostly by degree of distortion in Fe–L bond distances and L–Fe–L bond angles and are examples of distortion isomerism. The data of the complexes are compare and discuses with the data of familiar iron(III) complexes. The intermolecular interactions of all compounds are studied by Hirshfeld surface analysis.