SCSC Transformation of Heterobimetallic 2D MOF to Homometallic 2D MOF via Solvent-Assisted Removal of Second Metal Component: An Add-and-Remove Strategy.

Constructing high-dimensional metal-organic framework (MOF) materials that cannot be reached by direct methods is demanding. We herein report the construction of a two-dimensional (2D) copper(I) iodide MOF via an add-and-remove strategy of a second metal component (HgI2). The networking reaction of an O2S2-macrocycle (L) with CuI via a bridging exocyclic coordination under the direct condition was unsatisfactory because of its one-dimensional (1D) product {[(μ4-Cu3I3)(L)2]·2CH3CN·CH2Cl2}n (1) with low yield. Alternatively, the self-assembly of L with a mixture of CuI and HgI2 allows the generation of a 2D heterobimetallic Cu(I)/Hg(II)-MOF {[Cu2(μ-Hg2I4)(L)2(CH3CN)2I2]·toluene}n (2, brick wall) cross-linked by μ-Hg2I4 square dimers via the bridging exocoordination mode. When the crystals of 2 were immersed in methanol, the crystals were converted to a desired 2D Cu(I)-MOF [(μ4-Cu2I2)(L)2]n (3, square grid) by the replacement of the cross-linker μ-Hg2I4 with μ4-Cu2I2 via the solvent-assisted etching. Interestingly, this 2D-[1D]*-2D conversion process that proceeds in an SCSC mode is completed by the dimerization of open coordinating site CuI* to form a μ4-Cu2I2 node (2CuI* → Cu2I2), preserving the 2D dimensionality. The conversion process is discussed based on PXRD, EDX, AFM, TGA, and NMR data.