1H NMR and X-ray crystallographic analysis of 1,2-bis(4,6-diethylthio-1H-pyrazolo[3,4-d]pyrimidin-1-yl)ethane and its ‘propylene linker’-analog: molecular recognition versus crystal engineering
                                
                                    
                                        作者:Kamlakar Avasthi、Diwan S Rawat、Prakas R Maulik、S Sarkhel、Charlotte K Broder、Judith A.K Howard                                    
                                    
                                        DOI:10.1016/s0040-4039(01)01478-2
                                    
                                    
                                        日期:2001.10
                                    
                                    Proton NMR analysis on newly synthesized 1,2-bis(4,6-diethylthio-1H-pyrazolo[3,4-d]pyrimidin-1-yl)ethane, 2c, and 1,2-bis(4,6-diethylthio-1H-pyazolo[3,4-d]pyrimidin-1-yl)propane, 2d. showed intramolecular stacking in solution. X-Ray crystallography on 2c and 2d. however, confirmed the presence of such intramolecular stacking only in case of the 'propylene linker' compound. 2d. while the 'ethylene linker' compound. 2c. was devoid of it. (C) 2001 Elsevier Science Ltd. All rights reserved.