低碘化物

According to the H NMRstudy, it was found that the protons on the cyclopentadienyl ring of 〓 were not splitted, but when one proton on the cyclopentadienylring was substituted by methyl, that is in〓 complexes, thefour protons on the ring were splitted into four groups,the 〓 between the onesignal and the others is large, the total splitting is over 2ppm. The splittings werealso affected by the halides linked with the titanium, they increase according to theorder of CI, Br, I. By the study of the 〓 Sn NMR, it is found that the chemicalshifts of 〓 are present in low field. It is assume that the large space strain causesthe angles of the tin linked with ligands deviate from the normal tetrahedral anglesresults low field shift for 〓Sn. And by MS study,there were no molecular ions for 〓 complexes in the spectra. However, for 〓 when X=CI,Br,NCO and Ar is tolyl or phenyl group,there were molecular ions,but theirabundances were very small,and no that for the iodide was found.

钛上的卤素对茂环氢的裂分也有影响，依〓，Br，I顺序，卤素对茂环氢的裂分依次加大；通过对〓的研究发现，以上这些化合物〓的化学位移都出现在低场，认为大的空间张力造成的锡的键角偏离正常的锡的四面体键角是造成〓化学位移出现在低场的原因；对这些化合物质谱的研究发现，〓系列化合物得不到分子离子峰，而〓系列的化合物，当X=〓，NCO和苯环上不带取代基或只带甲基时，则出现分子离子峰，但丰度很低，而相应的碘化物和其它化合物则没出现分子离子峰。

Methods IO(superscript - subscript 3) was prepared by quantitative oxidation of bromine water, with the excessive bromine removed with formic acid. In the presence of excessive iodide, I(superscript -) would be oxidized by I(superscript - subscript 3) to form 3 times of I(superscript - subscript 3) in mol, displaying maximal absorption at 286nm in ultraviolet zone and a slightly low apex at 345nm.ε286=1.3×10^5 Lmol^(-1)cm^(-1),ε345=8.1×10^4 Lmol^(-1)cm^(-1), with both showing high sensitivity.

利用溴水定量氧化I生成IO(上标-下标 3)，再用甲酸除去过量的溴，IO(上标-下标 3)在过量碘化物存在下氧化I产生3倍摩尔量的I(上标-下标 3)，在紫外光区的286nm具有最大吸收，并在345nm处另有一略低的吸收峰，ε286=1.3×10^5 Lmol^(-1)cm^(-1)，ε345=8.1×10^4 Lmol^(-1)cm^(-1)，均具有很高的灵敏度。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。