Hydrogen-bonded supramolecular architectures and functional material design.

摘要

This dissertation is divided into two parts (I) fundamental crystal engineering and (II) design of functional solids.; The relative stabilities of carboxylic acid and 2-pyridone synthons were examined in organic cocrystals containing these two functionalities. 2-Pyridone synthon was shown to be more robust than carboxylic acid synthon, which was also supported by semi-empirical calculations of their stabilization energy.; Formation of dianions instead of thermodynamically more stable monoanions of dicarboxylic acids in the presence of an organic base was investigated in a series of salts containing various dicarboxylic acids and 2-aminopyridine. Thermodynamic and crystallographic data demonstrated that both pK_a values and hydrogen bond interactions play important roles in the formation of dianions.; The reliability of O-H…N hydrogen bond between pyridine and carboxylic acid groups was probed in organic hydrogen-bonded crystals. It was shown that the N-H…O hydrogen bond was the primary interaction between dicarboxylic acids and oximepyridines, even though a number of different interactions were possible. Therefore, the pyridine-carboxylic acid interaction was shown to be a useful supramolecular synthetic tool.; Monoanions of dicarboxylic acids were used with bi-functional conjugated acids of organic bases to construct layered architectures. Their conjugated acids were able to reliably cross-link chains of anions into infinite 2-D layers, provided that the two hydrogen-bond donors of the bi-functional linker were arranged in opposite directions.; Supramolecular synthetic strategies were used to generate a new type of second-order nonlinear optical materials. Polarizable chromophores were grafted onto rigid 1-D hydrogen-bonded chains of monoanions of dicarboxylic acids through a nuleophilic addition reaction, which generates a chiral center. Crystallographic data showed that the rigid 1-D hydrogen-bonded backbone greatly reduced the orientational freedom of individual chromophores leading to an alignment of all the chromophores on the chain. Semi-empirical calculations and thermal measurements demonstrated that this type of materials have good nonlinear optical response and high thermal stability. It was shown that pure enantiomers of this type of compounds can be resolved by the formation and separation of diastereomeric salts using chiral bases, which guarantee that this type of compounds will crystallize in non-centrosymmetric structures.