Triaryl‐1,3,5‐triazinane‐2,4,6‐triones (Isocyanurates) Peripherally Functionalized by Donor Groups: Synthesis and Study of Their Linear and Nonlinear Optical Properties

Abstract

The linear optical (LO) and nonlinear optical (NLO) properties of a series of isocyanurates functionalized by donor arms at the periphery are reported herein. These octupolar derivatives were obtained in a straightforward way from commercial isocyanate derivatives and were fully characterized. Although several of these compounds are known, those that exhibited the largest NLO activities are all new compounds. In terms of second-order activity, several of these derivatives exhibit remarkable activity/transparency tradeoffs. In terms of third-order activity, the longer derivatives with the stronger donor groups (X = NH(2), NMe(2), or NPh(2)) were shown to possess significant two-photon absorption cross sections. These strongly luminescent derivatives exhibit two-photon absorption cross sections up to 410 GM. DFT computations were also conducted to unravel their electronic structures and to rationalize their NLO properties. To our knowledge, the present study is the first concerned with the nonlinear optical properties of these original cyclotrimers.

Triarylisocyanurate‐Based Fluorescent Two‐Photon Absorbers

“…Regarding the fluorene‐containing derivatives 3 , 4‐H , 4‐NPh 2 and 13 , these measurements reveal similar trends between these molecules to those previously established between 1‐X and 2‐X relatives (Figure ) . Thus, extension of the π ‐manifold on the three peripheral branches red‐shifts the lowest absorption band.…”

“…The new cyclotrimer 3 was isolated in one step from commercial 2‐fluorenyl isocyanate in good yields (53 %) by catalytic cyclotrimerisation following a workup previously used by some of us (Scheme ) …”

“…Sonogashira coupling reactions were used each time, starting either from the tri(4‐bromophenyl)‐isocyanurate precursor 1‐Br (route A) or from the triyne precursor 6 (route B) . When the corresponding arylalkyne is easily available, route A should be favored over route B, because the precursor 6 is obtained in two steps from the precursor 1‐Br in only 37 % yield, whereas 1‐Br is conveniently obtained at the gram scale in one step (88 % yield) from commercial 4‐bromophenyl isocyanate via a catalytic cyclotrimerisation …”

“…We could previously show that isocyanurates with extended arms, such as 2‐X (Scheme ) can be fluorescent and constitute fairly good two‐photons absorbers when functionalized by electron‐releasing X substituents . In order to gain more insight into the structural modifications that can simultaneously favour fluorescence and 2PA, we have now synthesized and studied new derivatives presenting related structures.…”

Tunable molecular configuration for significant enhancement of two-photon absorption based on novel octupolar benzoimidazole derivatives

“…Atomic basis sets were applied numerically in terms of a double numerical plus polarization (DNP) function (including a polarized d-function for all non-hydrogen atoms and p-function for all hydrogen atoms and a global orbital cutoff of 4.4Å was employed [20]. The size of the DNP basis set is comparable to , but the DNP is more accurate than the corresponding Gaussian basis set [21].…”