摘要
文章分为三部分 :第一部分 ,描述通过四圆衍射仪 ,利用X射线单晶衍射法 ,所测得的芳砜CH3CONHC6 H4SO2 R(R =CH3,CH2 CONH2 ,CH2 CH2 OH)的晶体及分子结构结果 ;第二部分 ,对分子内键角和键长的测试结果进行分析 ,证明了甲砜分子内超共轭效应的存在 ,解释了甲砜分子红外吸收的特异性是由甲砜基团内超共轭效应引起的 ,找到了认证甲砜的红外特征峰 ,并揭示了超共轭效应的某些特性 ;第三部分 ,描述芳砜的合成 ,晶体的制备 。
A branched absorption peak with medium intensity at (970±20) cm -1 appears only in the infrared spectra of methylsulfones.The below mentioned aromaticsulfones are chosen to reveal the specificity.Crystal and molecular parameters of CH 3CONH C 6H 4 SO 2R(R= CH 3, CH 2CH 2OH) CH 2CONH 2, ,are determined by application of single crystal diffraction of X ray through Nicolet R3M/E diffracometer.The existence of hyperconjugation and its natures in group SO 2CH 3 ,confirmed by further analyses on the parameters,result in the specificity of IR absorption of the group,which is proved characteristic and can be used to identify methylsulfones. The first part describes the detection results,ascertains their crystal and molecular structures,and shows that the aromaticsulfone exists as cross linking multi molecules when R= CH 2CONH 2 or as double molecules when R= CH 2CH 2OH because of H bonds. The second part covers analyses on their molecular structures.The analyses demonstrate the hyperconjugation between σ S C and π S C in group SO 2CH 3. Two σ C H hyperconjugate with π S O .The strength of hyperconjugated bond CH decreases and its length tends longer.Due to the effect,the bond SC is not a pure single bond σ,but one which possesses a certain degree of a double bond.Its IR wave number,between those of σ S C and π S C ,attributes to the medium branched peak at (970±20) cm -1 .The peak branch reflects two groups of the most stable hyperconjugating conformational isomers.The hyperconjugation is weakened by the substitution of one non H group for one H atom in SO 2CH 3 and if the non H group does not conjugate with π S O ,the absorption at (970±20) cm -1 disappears as a characteristic peak.The intensity of absorption at (970±20) cm -1 conforms to the intensity of hyperconjugation between π S O and its adjacent σ C H . The third part introduces syntheses of the products,crystal preparations and their detections through X ray diffraction.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2000年第1期31-39,共9页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金资助项目
关键词
甲砜
晶体结构
超共轭效应
红外特征峰
芳砜
Hyperconjugation, Methylsulfones, Characteristic Infrared Absorption, Crystal Structure, Molecular Structure
