Rational Assembly of Three-component Coordination Polymers as Heterogeneous Catalysts for CO2 Cycloaddition and Cyanosilylation Reactions

Four new coordination polymers based on 5-(((1H-imidazol-2-yl)methyl)amino) isophthalic acid (H3L) and auxiliary ligands (1,10-phenanthroline, 2,2 '-bipyridine, and 4,4 '-bipyridine), namely, {[Zn(HL)(phen)(H2O)] & sdot; 2H(2)O}(n) (CP 1), {[Ni(HL)(phen)(H2O)]}(n) (CP 2), {[Ni(HL)(2,2 '-bpy)(H2O)] & sdot; 2H(2)O}(n) (CP 3) and {[Cd(HL)(4,4 '-bpy)(0.5)(H2O)] & sdot; 2H(2)O}(n) (CP 4) were rationally assembled. Furthermore, these four CPs were screened as heterogeneous catalysts for CO2 cycloaddition and cyanosilylation reactions under mild conditions. The catalytic experiments showed that CP 1 had the better catalytic performance, excellent substrate tolerance and recyclability for the above two reactions. It is speculated that the excellent activity of CP 1 may be due to the open Lewis base site and the Lewis acidic characteristics of the zinc (II) center. After five cycles, the catalytic activities of CP 1 did not significantly decrease, and the structures remained unchanged. Therefore, the CP 1 was considered efficient and stable heterogeneous catalysts for above the two reactions.