Crystallographic evidence of nitrate-pi interactions involving the electron-deficient 1,3,5-triazine ring.
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.
Maheswari
Palanisamy Uma
PU
Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
Modec
Barbara
B
Pevec
Andrej
A
Kozlevcar
Bojan
B
Massera
Chiara
C
Gamez
Patrick
P
Reedijk
Jan
J
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*
D000097:Acetonitriles; D009566:Nitrates; D014227:Triazines; D006859:Hydrogen; D010100:Oxygen; C032159:acetonitrile