Large Nonlinear Optical Responses of Dimers Bearing a Donor and Acceptor: Long, Intradimer Multicenter Bonding

Abstract

Unusual long, multicenter dimers bearing a large electron donor and acceptor have been the subject of great interest over the last decades due to their better conducting, superconducting, magnetic, or other physical properties. Twoelectron, multicenter bonding between two interplanar fragments has been recently recognized as a novel and important bonding interaction. Herein, the [TTF][TCNE], [TTF][TCNQ], [TTF][TCNP], and [TTF][TCNB] dimeric species have been studied by quantum mechanics methods with the view of assessing their interactions and first hyperpolarizabilities. It is found that the stabilities of the dimers primarily originate from the electrostatic bonding component. Although to a lesser extent, long, multicenter interactions due to the overlap of the molecular orbitals of the monomers are important also in the stability of these systems. Significantly, a severe hyperpolarizability decrease with changing the acceptor monomers of the dimeric species is qualitatively explained in terms of change in their charge transfer patterns. It indicates that the first hyperpolarizabilities of these dimers can be optimized by controlling their relative acceptor monomers. We believe that these results shall provide important information for further exploration of long, multicenter dimers with versatile and fascinating nonlinear optical properties.

1D versus 2D cocrystals growth via microspacing in-air sublimation

“…Moreover, owing to the synergistic effects of the individual components in cocrystals, new and valuable properties emerge not just from the activity of individual molecules but from their collective arrangement. Thus, cocrystals have attracted extensive attentions in many fields such as organic semiconductors 10,11 , nonlinear optics 12 , ferroelectrics 13,14 , energy transfer systems 15,16 , and energetic materials 17,18 . The co-assembly of multicomponents has been thoroughly investigated in the context of supramolecular chemistry and molecular crystal engineering, where normally the halogen bonds, hydrogen bonds, π–π interactions, charge-transfer (CT) interactions or other noncovalent interactions are in charge of the assembly forces.…”

FALDI‐based decomposition of an atomic interaction line leads to 3D representation of the multicenter nature of interactions

“…Moreover, multiple ligands which can bridge metal–metal bonds—such as chlorine atoms or carbonyl ligands—have been discovered and are well‐known examples of formal M⋅⋅⋅X⋅⋅⋅M multicenter bonds . Relatively recently, unusually long, multicenter bonds between dimers of tetracyanoethylene have attracted a large amount of interest, as well as 4‐center‐2‐electron bonding . Even metallic bonding, consisting of a “sea of delocalized electrons,” has been classified as multicenter bonding …”

Products and Mechanistic Investigations on the Reactions of Hydrazines with Ozone in Gas-Phase

“…The frontier molecular orbitals [24] are often used to reveal the relationship between the electronic and geometric structures and to obtain qualitative information about the optical and electrical properties of molecules. The charges are computed by finding the electron population of each atom (Multiwfn) [25].…”