Sun, Qiangsheng;Jin, Ke;Huang, Yuhui;Guo, Jia;Rungrotmongkol, Thanyada;Maitarad, Phornphimon;Wang, Changchun published 《Influence of conformational change of chain unit on the intrinsic negative thermal expansion of polymers》 in 2021. The article was appeared in 《Chinese Chemical Letters》. They have made some progress in their research.Name: 3-(4-Aminophenoxy)aniline The article mentions the following:
Neg. thermal expansion (NTE) behavior has roused wide interest for the control of thermomech. properties of functional materials. Although NTE behaviors have been found in kinds of compounds, it remains challenging for polymers to achieve intrinsic NTE property. In this work, we systematically studied the conformational change of dibenzocyclooctadiene (DBCOD) derivatives between chair (C) and twist-boat (TB) forms based on d.-functional theory calculations, and found clear evidence of the relationship between the structure of DBCOD units and the thermal contraction behavior of the related polymers. In order to obtain the polymer with NTE property, two conditions should be met for the thermal contracting DBCOD related units as follows: (i) the TB conformation can turn into C conformation as the temperature increases, and (ii) the volume of C conformation is smaller than that of TB conformation. This rule should offer a guidance to exploration of the new intrinsic NTE polymers in the future. To complete the study, the researchers used 3-(4-Aminophenoxy)aniline (cas: 2657-87-6) .
3-(4-Aminophenoxy)aniline is one of ethers-buliding-blocks. Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. Name: 3-(4-Aminophenoxy)aniline The bonding of oxygen in ethers, alcohols, and water is similar. In the language of valence bond theory, the hybridization at oxygen is sp3.
Reference:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem