Organic materials, crystal engineering

Another major area of CSD-based research is the supramolecular stmctural organization and crystal engineering, and particularly the role of hydrogen bonding in the solid state. Although fhe initial incentive came from biomolecular chemistry, fhe results are equally important for inorganic, organometallic, and polymeric materials. 

Cf. e.g. the reviews on Conformational Polymorphism by J. Berstein in Organic Solid State Chemistry (Ed. G. R. Desiraju), Elsevier Amsterdam 1987, p. 471 or by G. R. Desiraju, Crystal Engineering, Material Science Monographs 54, Elsevier, Amsterdam 1989, p. 285. 

The persistent and distinctive structural features of the GS network effectively reduce crystal engineering to the last remaining (third) dimension. These features prompted our laboratory to synthesize related materials in which the monosulfonate components were replaced with disulfonates. We surmised that this would lead to a two-fold reduction in the amount of space occupied by the organic residues between the GS sheets, creating frameworks... 

G. Desiraju, Crystal Engineering. The Design of Organic Solids, Material Science Monographs, Vol. 54, Elsevier, Amsterdam, 1989. 

The development of chemistry in the last 20 years has revealed a significant shift of interest on the part of theoreticians and experimentalists [1,2]. Earlier, chemists attention was concentrated on atoms and atom-atom bonds. This strategy has been very successful in the creation of new molecules with unusual structures and with new chemical and physical properties. However, two decades ago, the primary objects of chemical studies become intermolecular interactions leading to complex molecular assemblies that exhibit unusual and often unique macro properties. This situation has dominated in all areas of modem chemical science from physical, organic, inorganic, and organometallic chemistry to material science and biochemistry, and has resulted in the formulation of new chemical disciplines supramolecular chemistry and crystal engineering. 

The applicable fundamental concepts of nonlinear integrated optics for SHG were outlined decades ago and can be found in a number of review papers [6-8]. The basic theory as applied to organic materials and polymers is of course unchanged from that for dielectric materials and these papers are still very useful. Some twenty plus years ago, nonlinear integrated optical experiments started to be conducted, but mostly on inorganics and crystals. The specific field of amorphous and semi-ordered organics came when the chemical engineering of nonlinear chromophores was developed. 

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