Temperature-induced Sn(Ⅱ) supramolecular isomeric frameworks as promising heterogeneous catalysts for cyanosilylation of aldehydes

Two novel Sn(Ⅱ) supramolecular isomeric frameworks,with the identical formula of {(NH2Me2)2[Sn(BDC)(SO4)]}n,Sn-CP-1-α(1) and Sn-CP-1-β(2)(H2BDC=terephthalic acid) were synthesized under solvothermal condition and fully characterized by single crystal X-ray diffraction(SCXRD),Fourier transform infrared spectroscopy(FTIR),ultraviolet-visible spectroscopy(UVVis),elemental analyses,and thermogravimetric analysis(TGA).Interestingly,the structures of 1 and 2 are governed by the temperature of the reaction,suggesting a temperature-induced supramolecular isomerism.The supramolecular isomers are primarily caused by the different bridging alignments of SO42–.Compounds 1 and 2 display 2 D layer and 3 D framework with different topologies,non-interpenetrated 44-sql and two-fold interpenetrated 4-connected dia topology,respectively.Due to Lewis acid properties of coordinatively unsaturated Sn(Ⅱ) sites in CPs,they have been utilized as heterogeneous catalyst for the cyanosilylation of aldehydes with an excellent conversion yield over 99% under solvent-free conditions.

Bottom-up construction of mesoporous supramolecular isomers based on a Pd_(3)L_(6) triangular prism as templates for shape specific aggregation of polyiodide

Bottom-up construction of highly complex architecture from simple components remains one of the long-standing challenges in chemistry.Herein two supramolecular isomers based on large trigonal prismatic Pd_(3)L^(1)_(6)building block are reported.Significantly,they can be controllably obtained by adjusting the solute concentration during crystal growth.Specifically,the square shape crystals,α-[Pd_(3)L^(1)_(6)](PF_(6))_(12)in the cubic system with I143 m space group,can be isolated from a high-concentration solution of Pd_(3)L^(1)_(6).Interestingly,a mesoporous cage assembled from eight Pd_(3)L^(1)_(6)units with a diameter of 24Åis observed in the crystal structure.For the low-concentration solution of Pd_(3)L^(1)_(6),the rectangular shape crystalsβ-[Pd_(3)L^(1)_(6)](PF_(6))_(12)are obtained,which crystallize in the hexagonal system with P 63/m space group,and display two-dimension packing pattern and one-dimension mesoporous channels(diameter ca.22Å)along the c axis.Moreover,the two supramolecular isomers were used as nanoporous reactors to induce the specific formation of polyiodides with different compositions and shapes as evidenced from single crystal X-ray diffraction studies.These findings provide a reference in targeting functional crystalline mesoporous supramolecular materials from a single complex building unit.