선형 3핵 망간 2차 조립 단위체로 이루어진 1D 기둥을 이용한 미세기공의 금속-유기 골격체

Abstract

A solvothermal reaction of 2,7-naphthalene dicarboxylic acid (H22,7-ndc) with MnCl2• 4H2O in dimethyl formamide (DMF) at 120 ℃ for 5 d gave brown block-shaped crystals. Single-crystal X-ray diffraction analysis revealed that it was a 3D metal-organic framework (MOF), [Mn3(2,7-ndc)3(DMF)2]n, which was built based on a linear trinuclear manganese cluster as a secondary building unit (SBU). The SBU is connected to two adjacent SBUs by two bridging μ2-carboxylates, which leads to an infinite 1D columnar structure. The 1D columns are further connected through the naphthalene moiety of 2,7-ndc to four adjacent 1D columns to form the microporous 3D MOF of pcu network topology with 1D solvent channels along the crystallographic [011] direction. When the solvent molecules in the cavity including some ligated ones were removed from the framework, the metal sites with reduced coordination numbers could be generated within the 1D solvent cavity. The MOF with some exposed metal sites has permanent micropores; however, the MOF with no ligated solvent molecules does not show any permanent porosity.