Alkynyl and Phosphonyl Substituted Nucleobases: A Case of Thermally Induced Conformational Polymorphism
作者:K. C. Kumara Swamy、Srinivasarao Allu、Venu Srinivas、E. Balaraman、K. V. P. Pavan Kumar
DOI:10.1021/cg101737x
日期:2011.6.1
Substituted nucleobases with alkynyl and phosphonyl groups wire investigated in the context of supramolecular interactions and possible use toward synthesis of nucleoside phosphonic acids (NPAs). The adeninyl compound (adeninyl-N-9)-CH2CH2CH2CH2C CH exhibits conformational polymorphism as revealed by X-ray structures determined at 200 and 298 K. Interestingly, in the compound (adeninyl-N-9)-(CH2)(15)CH3, the long aliphatic carbon chain does not show disorder. A rather unusual bending of alkyl chain, likely due to C center dot center dot center dot O interactions, is observed in the case of the thymine compound (thyminyl)-CH2CH2CH2C CH that possesses a terminal alkyne group. The, powerful hydrogen bond acceptor property of the phosphoryl oxygen (P=O) does not perturb (unless assisted by other hydrogen Bonding partners) the :homo base-pairing in the structures of most of the phosphonyl substituted nucleobases studied.