Crystal transformation in Mn(II) metal-organic frameworks based on a one-dimensional chain precursor

The solvothermal reaction of Mn(II) salts and 5-((4'-(tetrazol-5 ''-yl)benzyl)oxy)isophthalic acid (H3L) affords an Mn(II) based coordination polymer Mn(H2L)(2)(H2O)(2) (1), which possesses a one-dimensional (1D) chain structure. Using 1 as the precursor, three Mn(II) metal-organic frameworks, Mn3L2(2,2'-bpy) (2)center dot 5H(2)O (2), Mn3L2(H2O)(4) (3), and Mn4L2(HL)(H2O)(5)center dot 0.5H(2)O (4), with three-dimensional (3D) networks can be obtained by different strategies of crystal transformation. Upon introduction of 2,2'-bipyridine (2,2'-bpy) as the ligand and 2,2'-biquinoline-4,4'-dicarboxylic acid as the structural-directing agent, 1 undergoes irreversible crystal transformation into 2 and 3, respectively, and 1 can be transformed into 4 by increasing the reaction temperature. Interestingly, the irreversible structural transformation of 3 into 2 can be carried out by adding a 2,2'-bpy ligand. Notably, after the removal of coordinated water molecules, 1 and 3 exhibit good catalytic performance for the cyanosilylation reaction even at 0 degrees C.

Automated summary

The solvothermal reaction of Mn(II) salts and 5-((4'-(tetrazol-5 ''-yl)benzyl)oxy)isophthalic acid (H3L) leads to the formation of Mn(II) based coordination polymer with a one-dimensional chain structure, which can further transform into three different Mn(II) metal-organic frameworks with three-dimensional networks. These materials exhibit good catalytic performance.