Copper and copper-manganese 1D coordination polymers: Synthesis optimization, crystal structure and preliminary studies as catalysts for Baylis-Hillman reactions

This work reports the influence of experimental parameters (pH and counter-ion) in the synthesis of the 1D coordination polymer [Cu(IDA)(H2O)(2)](n). (IDA = iminodiacetate), named here Cu-IDA. Copper-manganese bimetallic coordination polymers were also obtained by isomorphic replacement into Cu-IDA structure, with different molar ratio of Cu2+ and Mn2+ ions, denoted here as Cu/Mn-IDA (0.9/0.1; 0.7/0.3 and 0.5/0.5). New coordination polymers are isostructural to Cu-IDA and amounts of manganese atoms inserted into crystalline structure were evaluated by single-crystal X-ray diffraction and Rietveld refinement. All coordination polymers obtained were also characterized by infrared absorption spectroscopy and thermogravimetric analysis. Homometallic and bimetallic compounds were evaluated as catalysts for Baylis-Hillman reaction with yields and reaction times comparable or superior to those in the literature. Compounds containing manganese cations shows higher catalytic performance, especially Cu/Mn-IDA (0.9/0.1) with yield 91% in 5 h of reaction. Results also indicate an important role played by the metallic centre in the catalytic mechanism.

Automated summary

This study investigated the influence of experimental parameters on the synthesis of coordination polymers and prepared copper-manganese bimetallic coordination polymers by isomorphic replacement. Compounds containing manganese cations showed higher catalytic performance, with Cu/Mn-IDA (0.9/0.1) demonstrating a yield of 91% in 5 hours of reaction. The metallic center was found to play an important role in the catalytic mechanism.