2D Poly(arylene vinylene) Covalent Organic Frameworks via Aldol Condensation of Trimethyltriazine

Abstract

Designing structural order in electronically active organic solids remains agreat challenge in the field of materials chemistry.Now,2Dpoly(arylene vinylene)s prepared as highly crystalline covalent organic frameworks (COFs) by basecatalyzeda ldol condensation of trimethyltriazine with aromatic dialdehydes are reported. The synthesized polymers are highly emissive (quantum yield of up to 50 %), as commonly observed in their 1D analogues poly(phenylene vinylene)s.The inherent well-defined porosity (surface area ca. 1000 m 2 g À1 , pore diameter ca. 11 for the terephthaldehyde derived COF-1) and 2D structure of these COFs also present an ew set of properties and are likely responsible for the emission color, which is sensitive to the environment. COF-1 is highly hydrophilic and reveals ad ramatic macroscopic structural reorganization that has not been previously observed in framework materials.

Synthesis of Vinylene‐Linked Two‐Dimensional Conjugated Polymers via the Horner–Wadsworth–Emmons Reaction

“…In particular, sp 2 ‐carbon‐linked (or vinylene‐linked) 2D CPs provide high chemical and thermal stabilities as well as complete π‐conjugation over the whole 2D polymer framework, making these materials highly attractive for various applications, such as in optoelectronics, spintronics, and energy storage [13–15] . Thus far, only Knoevenagel [13–15, 16] and other aldol‐type condensation [17–19] reactions have been reported for the synthesis of crystalline vinylene‐linked 2D CPs. However, Knoevenagel polycondensation provides cyano‐vinylene‐linked 2D CPs in which additional cyano‐groups on the conjugated backbone cause structural twisting due to steric hindrance [20] .…”

Thiophene‐Bridged Donor–Acceptor sp2‐Carbon‐Linked 2D Conjugated Polymers as Photocathodes for Water Reduction

“…[8,17,28] Recently, 2D sp 2 -carbon-linked (or vinylene-linked) conjugated polymers (2D CCPs) have attracted growing attention due to the extended π-conjugation over the whole 2D polymer framework as well as the high chemical stability against acids and bases, in contrast to imine-linked 2D COFs [9,17,19,20] However, most of the reported 2D CCPs are not suitable candidates for PEC applications due to the inefficient light harvesting and consequently large optical energy gaps in the range of 2.2-2.4 eV (Table S5, Supporting Information). [9,[21][22][23][24][25] One promising strategy to regulate the optoelectronic properties of 2D conjugated polymers is the incorporation of donor and acceptor (D-A) conjugated structures, [26] which can be beneficial for PEC applications.…”

A Vinylene‐Bridged Conjugated Covalent Triazine Polymer as a Visible‐Light‐Active Photocatalyst for Degradation of Methylene Blue

“…Porous organic polymers (POPs) are known for their highly tunable structure, engineered optoelectronic properties, metal‐free skeleton, and high physicochemical stabilities. [ 1,2 ] As a kind of POPs, sp 2 carbon bridged polymers, [ 3–13 ] which show conspicuous electrochemical and charge‐transfer properties, [ 3 ] have demonstrated to be robust scaffolds for photocatalysis. The sp 2 carbon bridge, which involves strong CC bond, has higher bond energy (728 kJ mol −1 ) than the polarized CN (352 kJ mol −1 ), CN (602 kJ mol −1 ), and aromatic CC connection (479 kJ mol −1 ).…”

“…The sp 2 carbon bridge, which involves strong CC bond, has higher bond energy (728 kJ mol −1 ) than the polarized CN (352 kJ mol −1 ), CN (602 kJ mol −1 ), and aromatic CC connection (479 kJ mol −1 ). [ 14 ] Thus, the generation of CC bridges hold great promise to build chemically ultrastable polymers through typical coupling methodologies like Knoevenagel reaction [ 3–13 ] or Wittig reaction. [ 15,16 ] To date, most of the reported sp 2 carbon conjugated polymers via Knoevenagel route involves the generation of substituted cyanovinylene bridge [CHC(CN) ].…”

“…[ 3,4,6–9 ] However, the limited tolerance of the electron‐withdrawing cyano groups may damage the chemical stability of the resulting materials. Very recently, a series of unsubstituted vinylene [CHCH] bridged polymers have been constructed by active arylmethyl carbons of 1,3,5‐trimethyl‐2,4,6‐triazine (TMT), [ 10–13 ] and can be termed as sp 2 carbon‐conjugated covalent triazine polymer (sp 2 c‐CTP). On the one hand, the nitrogen atoms in these triazine‐based polymers may act as active sites for redox reaction with its free electron pair and electron‐poor character.…”