【作者】 刘买利； 常旭红； 何水祥； 杜文虎；

【Author】 Liu Maili Chang Xuhong He Shuiyang* Du Wenhu *Instrumental Annalysis Research Center Department of Chemistry Northwest University,Xi’an,710069

【机构】 西北大学分析测试研究中心； 西北大学化学系；

【摘要】 本文应用1H和13C-NMR法研究了精氨酸(ARG.)及其稀土钕(Nd)配合物的波谱形为。ARG.为市售样品,在水溶液中与酸钕混和搅拌、析出晶态样品。样品用D2O溶解用于NMR测定(Bruker AC-80 NMR,5 mm样品管,1H和13C-NMR的工作频率分别为80.13和20.15MHz)。配合物1H和13C-NMR谱的归属较为直接,采用了常规的同核单频去偶(1H)和2D-异核相关方法。对于ARG.由于H2和H5、H3和H4的化学位移极为接近,给C3和C4归属带来了一些麻烦,其它几个C核的共振位置则较易确定。比较ARG.及其配合物中对应核的化学位移,证实只有酸基参与了配位键的生成,而胍基和α-氮基并未参与成键。形成配合物所引起的屏蔽和去屏蔽作用,沿6键交替变化,并且随着远离成键中逐渐减小C1(10.6 PPM),C2(-3.5 PPM),C3(3.9 PPM),C4(0.4 PPM),C5(0.3 PPM),C6(-0.1 PPM)。在杂环化合物质子化反应中亦观察到了类似的传递现象。对质子的影响都表现为去屏蔽作用,而且每靠近成键中心一个CH2,其化学位移的增加值越扩大一倍,这可以理解为形成配合物对质子的去屏蔽作用主要是通过空间传递的。在质子谱中没有观察到NH2(1)峰的存在,这显然是因为NH2(1)较活泼而与溶剂中的D发生了交换。更多还原

【Abstract】 The NMR spectroscopic properties of Arg.(Argunine)and its Nd complex were studied on a Bruker AC-80 NMR machine with operating frequences of 80.13 & 20.15 MHz for 1H & 13C respectively and 5mm double probe.The Arg Nd complex was crystallized from aqueous solution of Arg.and Nd(NO3)3. The samples were solved in D20 for NMR measurement.The 1H and 13C NMR spectrum assignment of the complex is straight forward by the homonuclear single frequence decoupling and heteronucear chemical shifts correlation experiment.The assignment of C3 and CA are difficult because the chemical shifts of H2 and H5,H3 and H4 are identical for Arg.. The formation of the complex was improved by the shielding and deshielding on C1(10.6 PPM),C2(-3.5 PPM),C3(3.9 PPM), CA(0.4 PPM),C5(0.3 PPM)and C6(-0.1 PPM),which is transfered through the band in the alternation way,and is similar as observed in the protonation of hetercycles.It seams that the -COOH group is the only one to form the complex,and there is no evidence that the -NH-C;NH(NH2)& 2-NH2 groups are involed.In contrast with 13C,formation of the complex causes the deshielding on all of the alkane proton,also interesting,the effect is tranafered through space and reduced about two times every -CH2- unit further away from the center of the complex.更多还原