TY - JOUR
T1 - Molecular structure and conformational dynamics of 3,12-dichloro-5,14-diphenyl-7,9a,16,18a-tetrazadibenzo[a,l]pentacene-9,18-dione
AU - Kovalevsky, A. Yu
AU - Shishkin, O. V.
AU - Ronova, I. A.
AU - Ponomarev, I. I.
AU - Lindeman, S. V.
AU - Volkova, Yu A.
PY - 1997/11
Y1 - 1997/11
N2 - The X-ray study of 3,12-dichloro-5,14-diphenyl-7,9a,16,18a-tetrazadibenzo(a,l)pentacene-9,18-dione (1), a model compound for a novel class of thermostable polyheteroarylenes, polyquinoquinazolones, has been carried out. The nonsymmetric flattened structure of the molecule observed is a result of intermolecular interactions. It was established using quantum-chemical calculations by the semiempirical AM1 method that the annelation of the 1,6-dihydropyrimidinone ring by aromatic cycles results in increasing the conformational flexibility of the dihydrocycle due to weakening the conjugation between the carbonyl group and the remaining π-system of the molecule. It was shown by X-ray study and quantum-chemical calculations that protonation of 1 results in a substantial change in the molecular structure due to the large contribution of the 1,4-dihydro tautomeric form to the structure of the 1,6-dihydropyrimidinone ring. A tendency for the conformational flexibility of the heterocycle to increase upon protonation was revealed.
AB - The X-ray study of 3,12-dichloro-5,14-diphenyl-7,9a,16,18a-tetrazadibenzo(a,l)pentacene-9,18-dione (1), a model compound for a novel class of thermostable polyheteroarylenes, polyquinoquinazolones, has been carried out. The nonsymmetric flattened structure of the molecule observed is a result of intermolecular interactions. It was established using quantum-chemical calculations by the semiempirical AM1 method that the annelation of the 1,6-dihydropyrimidinone ring by aromatic cycles results in increasing the conformational flexibility of the dihydrocycle due to weakening the conjugation between the carbonyl group and the remaining π-system of the molecule. It was shown by X-ray study and quantum-chemical calculations that protonation of 1 results in a substantial change in the molecular structure due to the large contribution of the 1,4-dihydro tautomeric form to the structure of the 1,6-dihydropyrimidinone ring. A tendency for the conformational flexibility of the heterocycle to increase upon protonation was revealed.
KW - 5,14-diphenyl-3,12-dichloro-7,9a,16,18a-tetrazadibenzo[a,l]pentacene-9,18-dione
KW - AM1
KW - Conformational analysis
KW - Molecular structure
UR - http://www.scopus.com/inward/record.url?scp=0031320108&partnerID=8YFLogxK
U2 - 10.1007/BF02503775
DO - 10.1007/BF02503775
M3 - Article
AN - SCOPUS:0031320108
SN - 1066-5285
VL - 46
SP - 1866
EP - 1874
JO - Russian Chemical Bulletin
JF - Russian Chemical Bulletin
IS - 11
ER -