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Basically, preparation techniques of nonlinear optical coordination polymers (CPs) rely on introducing noncentrosymmetric crystal structure, i.e. which is devoid of mirror symmetry element. The first is using the enantiomerically pure linking compounds or relies on induction on noncentrosymmetry using chiral auxiliary compounds such as catalysts, additives, solvents as well as template species. The other approach relies on the spontaneous breaking symmetry, which originates from the spontaneous self-assembly of achiral linkers, without the use of chiral organic ligands or other chiral reagents.   please visit for more datils 

https://www.mediafire.com/file/vzkp2uzrgulgwab/article_1.pdf