Synthesis of Vinylene-Linked Two-Dimensional Conjugated Polymers via the Horner-Wadsworth-Emmons Reaction
In this work, we demonstrate the first synthesis of vinylene-linked 2D CPs, namely, 2D poly(phenylenequinoxalinevinylene)s 2D-PPQV1 and 2D-PPQV2, via the Horner–Wadsworth–Emmons (HWE) reaction of C2-symmetric 1,4-bis(diethylphosphonomethyl)benzene or 4,4′-bis(diethylphosphonomethyl)biphenyl with C3-symmetric 2,3,8,9,14,15-hexa(4-formylphenyl)diquinoxalino[2,3-a:2′,3′-c]phenazine as monomers. Density functional theory (DFT) simulations unveil the crucial role of the initial reversible C−C single bond formation for the synthesis of crystalline 2D CPs. Powder X-ray diffraction (PXRD) studies and nitrogen adsorption-desorption measurements demonstrate the formation of proclaimed crystalline, dual-pore structures with surface areas of up to 440 m2 g−1. More importantly, the optoelectronic properties of the obtained 2D-PPQV1 (Eg=2.2 eV) and 2D-PPQV2 (Eg=2.2 eV) are compared with those of cyano-vinylene-linked 2D-CN-PPQV1 (Eg=2.4 eV) produced by the Knoevenagel reaction and imine-linked 2D COF analog (2D-C=N-PPQV1, Eg=2.3 eV), unambiguously proving the superior conjugation of the vinylene-linked 2D CPs using the HWE reaction.
Synthesis of Vinylene-Linked Two-Dimensional Conjugated Polymers via the Horner-Wadsworth-Emmons Reaction
In this work, we demonstrate the first synthesis of vinylene-linked 2D CPs, namely, 2D poly(phenylenequinoxalinevinylene)s 2D-PPQV1 and 2D-PPQV2, via the Horner–Wadsworth–Emmons (HWE) reaction of C2-symmetric 1,4-bis(diethylphosphonomethyl)benzene or 4,4′-bis(diethylphosphonomethyl)biphenyl with C3-symmetric 2,3,8,9,14,15-hexa(4-formylphenyl)diquinoxalino[2,3-a:2′,3′-c]phenazine as monomers. Density functional theory (DFT) simulations unveil the crucial role of the initial reversible C−C single bond formation for the synthesis of crystalline 2D CPs. Powder X-ray diffraction (PXRD) studies and nitrogen adsorption-desorption measurements demonstrate the formation of proclaimed crystalline, dual-pore structures with surface areas of up to 440 m2 g−1. More importantly, the optoelectronic properties of the obtained 2D-PPQV1 (Eg=2.2 eV) and 2D-PPQV2 (Eg=2.2 eV) are compared with those of cyano-vinylene-linked 2D-CN-PPQV1 (Eg=2.4 eV) produced by the Knoevenagel reaction and imine-linked 2D COF analog (2D-C=N-PPQV1, Eg=2.3 eV), unambiguously proving the superior conjugation of the vinylene-linked 2D CPs using the HWE reaction.
