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1.有机磷化合物的P=O频率在1160—1400厘米~(-1),P=S频率在540—750厘米~(-1)。这些频率都因取代基不同而变化很大,随取代基电负性增大,频率也显著提高。 2.P=O频率与取代基电负性和∑x之间呈良好的直线关系,其经验公式可写为υ_(P=0)=37.5∑x+950.1 利用这式,如果知道某一分子的P=O频率,就可求其取代基的电负性。 3.P=O频率的移位主要是由于取代基诱导效应的作用,使P=O键的力常数发生变化而引起。 4.P=S频率的移位较为复杂。除取代基的诱导效应外,当与P=S键直接相联的是第三或第四周期的硫、氯或溴原子时,这些原子还可能对P=S键产生另一效应,足以提高P=S键强度。
1. P = O organophosphorus compounds in the frequency of 1160-1400 cm -1, P = S frequency of 540-750 cm -1. These frequencies vary greatly depending on the substituents, as the electronegativity of the substituent increases, the frequency is significantly increased. 2.P = O frequency and substituent electronegativity and Σx showed a good linear relationship between the empirical formula can be written as υ_ (P = 0) = 37.5Σx + 950.1 Using this formula, if you know a certain molecule P = O frequency, you can find the electronegativity of the substituent. 3.P = O frequency shift is mainly due to the role of substituent-induced effect, the P = O bond force constant caused by changes. 4.P = S frequency shift is more complicated. In addition to the induction effect of substituents, these atoms may have another effect on the P = S bond when the sulfur, chlorine or bromine atoms of the third or fourth period are directly associated with the P = S bond, P = S key strength.