title: Crystallographic evidence of nitrate-pi interactions involving the electron-deficient 1,3,5-triazine ring.
abstract: The reaction of Zn(NO3)2.6H2O or Cu(NO3)2.3H2O with the star-shaped ligand 2,4,6-tris(di-2-picolylamino)[1,3,5]triazine (dipicatriz) in acetonitrile results in the formation of the mono- or trinuclear coordination compounds [Zn(dipicatriz)(NO3)2] (1), [Zn3(dipicatriz)(NO3)6](CH3CN)3 (2), and [Cu3(dipicatriz)(NO3)2(H2O)6](NO3)4 (3), depending on the metal-to-ligand ratios used during the crystallization process. Their crystal structures exhibit unique supramolecular interactions. Compounds 1 and 2 show anion-pi interactions between coordinated nitrate ions and the s-triazine ring. Compound 3 exhibits remarkable interactions between two noncoordinated nitrate anions and the two faces of the electron-deficient heteroaromatic ring, corroborating earlier theoretical investigations in this area. New theoretical investigations have been carried out on nitrate-pi interactions, taking into account the particular position of the anion toward the aromatic ring observed in the crystal structures.
authors.affiliation: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: Palanisamy Uma
authors.initials: PU
authors.lastname: Maheswari
authors.forename: Barbara
authors.initials: B
authors.lastname: Modec
authors.forename: Andrej
authors.initials: A
authors.lastname: Pevec
authors.forename: Bojan
authors.initials: B
authors.lastname: Kozlevcar
authors.forename: Chiara
authors.initials: C
authors.lastname: Massera
authors.forename: Patrick
authors.initials: P
authors.lastname: Gamez
authors.forename: Jan
authors.initials: J
authors.lastname: Reedijk
mesh_terms: D000097:Acetonitriles / Q000378:metabolism; D018360:Crystallography, X-Ray; D004583:Electrons; D006859:Hydrogen / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009566:Nitrates / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D013237:Stereoisomerism; D014227:Triazines / Q000737:chemistry*
chemical_list: D000097:Acetonitriles; D009566:Nitrates; D014227:Triazines; D006859:Hydrogen; D010100:Oxygen; C032159:acetonitrile