engleski

Synthesis, characterization and polymerization of aromatic trinitroso compounds

Aromatic C-nitroso compounds have the ability to dimerize reversibly to Z- or E-azodioxides. In solid state, they usually appear as azodioxy dimers or polymers, while in solution nitroso monomer- azodioxide equilibrium is established with monomers being the preferred form at ambient conditions. Especially interesting are compounds with multiple aromatic C-nitroso groups which can be employed as starting molecular building blocks for the design of new 1D, 2D and 3D polymeric azodioxides with desired structures and properties. For example, 1, 4- dinitrosobenzene polymerizes to remarkably stable 1D longchain azodioxy polymer which could be possibly used as organic semiconductor, while polymerization of monomers with tetrahedrally oriented nitroso groups leads to formation of porous 3D diamondoid azodioxy networks. Although the polymerization of suitably designed aromatic C- nitroso compouds undoubtly offers a uniqe pathway to new covalently bonded materials, the main obstacle that must be overcome to reach this goal is that compounds with multiple aromatic C-nitroso groups are not easily prepared. Herein, we focused on the synthesis and characterization of new aromatic trinitroso compounds and their possible self-polymerization to azodioxy networks. Selected target monomeric compounds differ in central unit (benzene, pyridine, triazine and amine) on which three phenyl rings with nitroso functionalities are attached (Fig. 1). Several synthetic approaches were tested and the obtained products were characterized by using different techniques (IR spectroscopy, solution- and solid-state NMR spectroscopy, powder X-ray diffraction and thermogravimetric analysis). The obtained results suggest formation of poorly soluble E-azodioxy oligomers or polymers of relatively good thermal stability. The computational study (binding energies, molecular electrostatic potential values and GCMC simulations) gave further insight into the possible structures of the predicted azodioxy linked porous organic materials and preferred binding modes with N2 and CO2.

aromatic trinitroso compounds ; self-polymerization ; porous organic polymers

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