Silver Thiolate Nano-sized Molecular Clusters and Their Supramolecular Covalent Frameworks: An Approach Toward Pre-templated Synthesis

A series of seven new complexes including silver-thiolate molecular clusters and their covalent supramolecular frameworks have been assembled from the silver carbide precursor Ag2C2 using a C-2(2-) pre-templated approach. Herein, two prototype clusters Ag-14(SR)(6) and CO3@Ag-m(SR)(10) (R=isopropyl, cyclohexyl or tert-butyl; m=18 or 20) are employed to construct cluster-based metal-organic frameworks of different dimensions. In particular, both new ellipsoidal tetradecanuclear molecular cluster compounds, namely, Ag-14(S-iPr)(6)(CO2CF3)(8).(DMSO)(6) (two polymorphic forms 1, 2) and [Ag-14(S-Cy)(6)(CO2CF3)(8).(DMSO)(4)](DMSO)(3) (3), and a cluster-based metal-organic framework {Ag-3[Ag-14(S-iPr)(6)(CO2CF3)(11)(H2O)(3)CH3OH].(H2O)(2.5)}(n) (4) have been isolated and structurally characterized. Furthermore, increased acidity of the reaction mixture afforded three carboxylate-templated cluster based frameworks: a chain-like compound {[HN(CH3)(2)CO].[CO3@Ag-18(S-tBu)(10)(NO3)(7)(DMF)(4)].DMF}(n) (5), as well as two layer-type compounds, namely, {Ag[CO3@Ag-20(S-iPr)(10)(CO2CF3)(9)(CO2HCF3)(CH3OH)(2)]}(n) (6) and {Ag-2[CO3@Ag-20(S-Cy)(10)(CO2CF3)(10)(CO2HCF3)(2)(H2O)(2)].(H2O)(3.)(CH3OH)(3)}(n) (7) exhibiting sql-net characteristics. It is demonstrated that the C=C2- pre-template, which draws several Ag+ ions together to form the C-2@Ag-n entity, plays an indispensable role in the syntheses of these compounds. Furthermore, covalent linkage of these nano-sized silver thiolate clusters from one- to three-dimensions revealed enormous potential for the future development of silver cluster-based frameworks.