Synthese von Coil-Rod-Coil-Blockcopolymeren und Synthese "haariger" MOFs

Brokmann L. Synthese von Coil-Rod-Coil-Blockcopolymeren und Synthese "haariger" MOFs. Bielefeld: Universität Bielefeld; 2019

High Efficiency Platinum Acetylide Nonlinear Absorption Chromophores Covalently Linked to Poly(methyl methacrylate)

Shelton AH, Price RS, Brokmann L, Dettlaff B, Schanze KS. High Efficiency Platinum Acetylide Nonlinear Absorption Chromophores Covalently Linked to Poly(methyl methacrylate). Acs Applied Materials & Interfaces. 2013;5(16):7867-7874.We report three platinum acetylide acrylate monomers containing known two-photon absorption (TPA) chromophores and their covalent incorporation into polymers via free radical polymerization with methyl methacrylate. The photophysical properties of the platinum acetylide monomers and resulting poly(methyl methacrylate) (PMMA) copolymers were investigated to determine if the one- and two-photon photophysical properties of the chromophores were maintained in the copolymers. The photophysical properties of the series of copolymers were studied in solution and solid state with minimum shifts exhibited in the ground state absorption, photoluminescence, and triplet-triplet transient absorption spectra. The polymer films displayed markedly stronger phosphorescence and longer triplet excited state lifetimes than the polymers in solution or the monomers. The incorporation of the platinum acetylide chromophores into the PMMA copolymers allows the materials to be cast as thin films or into free-standing monoliths. Films with similar to 3.6 mu m in thickness and monoliths with 1 mm path length were fabricated and examined. The nonlinear absorption responses of the polymers in solution were measured via the nanosecond z-scan method, and the solid state polymer monoliths were measured via nonlinear transmittance. Both measurements indicate that the polymers exhibited strong transmittance attenuation at input pulse energies exceeding 100 mu J

Postsynthetic Modification of Metal-Organic Frameworks through Nitrile Oxide-Alkyne Cycloaddition

von Zons T, Brokmann L, Lippke J, et al. Postsynthetic Modification of Metal-Organic Frameworks through Nitrile Oxide-Alkyne Cycloaddition. INORGANIC CHEMISTRY. 2018;57(6):3348-3359.Postsynthetic modification of metal-organic frameworks is an important method to tailor their properties. We report on the nitrile oxide-alkyne cycloaddition (NOAC) as a modification tool, a reaction requiring neither strained alkynes nor a catalyst. This is demonstrated with the reaction of nitrile oxides with PEPEP-PIZOF-15 and-19 at room temperature. PIZOF-15 and-19 are porous Zr-based MOFs (BET surface areas 1740 and 960 m(2) g(-1), respectively) consisting of two mutually interpenetrating UiO-type frameworks with linkers of the type -O2C[PE-P(R-1,R-2)-EP]CO2- (P, phenylene; E, ethynylene; and R-2, side chains at the central benzene ring with R-1 = R-2 = OCH2C CH or R-1 = OCH2C CH and R-2 = O(CH2CH2O)(3)Me). Their syntheses, using benzoic acid as a modulator, and their characterization are reported herein. The propargyloxy (OCH2C CH) side chains contain the ethyne moieties needed for NOAC. Formation of nitrile oxides through oxidation of oximes in aqueous ethanolic solution in the presence of PEPEP-PIZOF-15 and -19 resulted in the reaction of 96-100% of the ethyne moieties to give isoxazoles. Thereby the framework was preserved. The type of nitrile oxide RCNO was greatly varied with R being isopentyl, tolyl, 2-pyridyl, and pentafluorophenyl. A detailed NMR spectroscopic investigation showed the formation of the 3,5-disubstituted isoxazole to be clearly favored (>96%) over that of the constitutional isomeric 3,4-disubstituted isoxazole, except for one example

High Efficiency Platinum Acetylide Nonlinear Absorption Chromophores Covalently Linked to Poly(methyl methacrylate)

We report three platinum acetylide acrylate monomers containing known two-photon absorption (TPA) chromophores and their covalent incorporation into polymers via free radical polymerization with methyl methacrylate. The photophysical properties of the platinum acetylide monomers and resulting poly­(methyl methacrylate) (PMMA) copolymers were investigated to determine if the one- and two-photon photophysical properties of the chromophores were maintained in the copolymers. The photophysical properties of the series of copolymers were studied in solution and solid state with minimum shifts exhibited in the ground state absorption, photoluminescence, and triplet–triplet transient absorption spectra. The polymer films displayed markedly stronger phosphorescence and longer triplet excited state lifetimes than the polymers in solution or the monomers. The incorporation of the platinum acetylide chromophores into the PMMA copolymers allows the materials to be cast as thin films or into free-standing monoliths. Films with ∼3.6 μm in thickness and monoliths with 1 mm path length were fabricated and examined. The nonlinear absorption responses of the polymers in solution were measured via the nanosecond <i>z</i>-scan method, and the solid state polymer monoliths were measured via nonlinear transmittance. Both measurements indicate that the polymers exhibited strong transmittance attenuation at input pulse energies exceeding 100 μJ

Postsynthetic Modification of Metal–Organic Frameworks through Nitrile Oxide–Alkyne Cycloaddition

Postsynthetic modification of metal–organic frameworks is an important method to tailor their properties. We report on the nitrile oxide–alkyne cycloaddition (NOAC) as a modification tool, a reaction requiring neither strained alkynes nor a catalyst. This is demonstrated with the reaction of nitrile oxides with PEPEP-PIZOF-15 and -19 at room temperature. PIZOF-15 and -19 are porous Zr-based MOFs (BET surface areas 1740 and 960 m² g^–1, respectively) consisting of two mutually interpenetrating UiO-type frameworks with linkers of the type ^–O₂C­[PE-P­(R¹,R²)-EP]­CO₂^– (P, phenylene; E, ethynylene; R¹ and R², side chains at the central benzene ring with R¹ = R² = OCH₂CCH or R¹ = OCH₂CCH and R² = O­(CH₂CH₂O)₃Me). Their syntheses, using benzoic acid as a modulator, and their characterization are reported herein. The propargyloxy (OCH₂CCH) side chains contain the ethyne moieties needed for NOAC. Formation of nitrile oxides through oxidation of oximes in aqueous ethanolic solution in the presence of PEPEP-PIZOF-15 and -19 resulted in the reaction of 96–100% of the ethyne moieties to give isoxazoles. Thereby the framework was preserved. The type of nitrile oxide RCNO was greatly varied with R being isopentyl, tolyl, 2-pyridyl, and pentafluorophenyl. A detailed NMR spectroscopic investigation showed the formation of the 3,5-disubstituted isoxazole to be clearly favored (≥96%) over that of the constitutional isomeric 3,4-disubstituted isoxazole, except for one example