Spiral Structure And The Theory Of Optical Activity Of Chiral Molecules

Most of the bimolecules are chiral. In this paper we have investigated the relations, which are the chiral structures or the charge of chiral atom and the other atoms connecting the chiral atom with their optical activity by using theoretical calculation.Material property should be determined by their structure, so the optical activity must has much relation with the structure, and the helical theory denotes the helical structure results in the optical activity, which means the structure are real cause leading to optical activity. Of course, the theory proves this point by much examples, for instance, the helical brass wires also exist optical activity.In this paper, we explore further the relation between the charge of chiral atom and other atom connecting of chiral atom and optical activity under the basis of helical theory. And we have realized the specially relation between the charge of chiral atom and optical activity by the experiment data. Because the charge of atoms distribution can influence the molecule structure, so considering the charge factor can reveal the essence of optical activity caused.Six different configuration of 2-pentanol are obtained through optimized at B3LYP/6-311++G(d,p) and B3LYP/6-311++G(2d,2p) base sets. At the same time, we also get their optical rotation. We discuss the charge of chiral atom and other atoms connecting the chiral atom to influence the optical activity, the mostly experiment data satisfy for our predict; We get the result which the more plus chiral atom charge, bigger bond angle and charge of other atom connecting the chiral atom are good for the optical rotation. As the optical rotation can be determined by many factors, so the least datas can not be explained by the charge factor.We also optimize the neutral, the negative charge state and the plus state of alanine at B3LYP/6-311++G (d, p) and B3LYP/6-311++G (2d,2 p) base set, and obtain the optical rotation at those base sets. And we discuss the difference reasons causing different optical rotation among the three states. The structure, charge and bond angle are considered to show their different optical rotation. And we mainly get the result:the more bond angle, the more contribution to optical rotation.We optimized eight different configurations of propionamide alanine at the B3LYP base set (6-311++G (d, p) and HF 6-311++G (d, p)) and computed their optical rotations. We mainly discuss the two different of propionamide alanine contribution to the molecule. We can get:the more charge of the chiral atom, the more contribution to optical rotation.