A new design strategy for efficient electro-optic single-component organic crystals

Polarity of Organic Supramolecular Materials: A Tunable Crystal Property

“…To take full advantage of tunability, molecular bricks should preferably provide E N +0. With respect to both types of interactions # and N, we arrive at a conclusion opposite to what &&Crystal engineering'' claims: van der =aals interactions for a 2D con,nement and one most nonbonding recognition motive can optimize polarity formation in host}guest systems (6). Polarity resulting from individual molecular bricks is a complex physical property of molecular crystals which can systematically be tuned by chemical synthesis.…”

“…Just for simplicity's sake we will discuss polarity formation for G "03 (i"1), although in most crystal structures tensorial properties undergo some reduction by transformation of molecular tensors to the coordinate system of the lattice (13). However, some type of elongated A} }D molecules have the tendency to align axes (6). It is important to emphasize here that we cannot predict G values by our theoretical models.…”

“…7) (9, 16). By other approaches one may introduce steric substituents to the -frame of A} }D molecules with the aim of reducing the tendency for antiparallel packing (6).…”

“…[7] is most accurate for x near to 1 (33). Equation [6] re#ects again the nature of an isomerization reaction, leading to polarity. The driving force for the noncooperative alignment of dipoles is simply E , the fundamental (f ) energy di!erence in polarity formation for E N "0.…”

SYNTHESIS AND X-RAY CRYSTAL STRUCTURE OF THE ASYMMETRIC DITHIADIAZENE BrC6F4NSNSC6H4NO2

“…Perfluorination tends to minimize interactions between these polar chains and so favor the formation of polar acentric structures. 4 As an extension of this work, we have begun an examination of thiazyl chains as π-delocalized spacer groups between donor-acceptor substituted perfluorinated aromatic rings. The extended delocalization is expected to enhance the molecular NLO response.…”