Premium
Evidence for stereoelectronic effects in the N—C—N group of 8,10,12‐triaza‐1‐azoniatetracyclo[8.3.1.1 8,12 .0 2,7 ]pentadecane 4‐nitrophenolate 4‐nitrophenol monosolvate from the protonation of aminal (2 R ,7 R )‐1,8,10,12‐tetraazatetracyclo[8.3.1.1 8,12 .0 2,7 ]pentadecane: X‐ray and natural bond orbital analysis
Author(s) -
Rivera Augusto,
Uribe Juan Manuel,
RíosMotta Jaime,
Osorio Hector Jairo,
Bolte Michael
Publication year - 2015
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229615004829
Subject(s) - natural bond orbital , chemistry , crystallography , hydrogen bond , lone pair , anomeric effect , stereochemistry , bond order , single bond , antibonding molecular orbital , bond length , crystal structure , molecule , computational chemistry , density functional theory , atomic orbital , group (periodic table) , anomer , organic chemistry , physics , quantum mechanics , electron
The title molecular salt, C 11 H 21 N 4 + ·C 6 H 4 NO 3 − ·C 6 H 5 NO 3 , (II), crystallizes with two independent three‐component aggregates in the asymmetric unit. In the cations, the cyclohexane rings fused to the cage azaadamantane systems both adopt a chair conformation. In the crystal structure, the aggregates are connected by C—H...O hydrogen bonds, forming a supramolecular unit enclosing an R 4 4 (24) ring motif. These units are linked via C—H...O and C—H...N hydrogen bonds, forming a three‐dimensional network. Even hydrogen‐bond formation to one of the N atoms is enough to induce structural stereoelectronic effects in the normal donor→acceptor direction. The C—N bond distances provide structural evidence for a strong anomeric effect. The structure also displays O—H...O and N—H...O hydrogen bonding. Geometric optimization and natural bond orbital (NBO) analysis of (II) were undertaken by utilizing DFT/B3LYP with the 6‐31+G(d,p) basis set. NBO second‐order perturbation theory calculations indicate donor–acceptor interactions between nitrogen lone pairs and the antibonding orbital of the C—C and C—N bonds for the protonated polyamine, in agreement with the occurrence of bond‐length and bond‐angle changes within the aminal cage structure.