Synthesis and Characterization of Dimethylbis(2-pyridyl)borate Nickel(II) Complexes: Unimolecular Square-Planar to Square-Planar Rotation around Nickel(II)

The syntheses of novel dimethylbis­(2-pyridyl)­borate nickel­(II) complexes <b>4</b> and <b>6</b> are reported. These complexes were unambiguously characterized by X-ray analysis. In dichloromethane solvent, complex <b>4</b> undergoes a unique square-planar to square-planar rotation around the nickel­(II) center, for which activation parameters of Δ<i>H</i>^⧧ = 12.2(1) kcal mol^–1 and Δ<i>S</i>^⧧ = 0.8(5) eu were measured via NMR inversion recovery experiments. Complex <b>4</b> was also observed to isomerize via a relatively slow ring flip: Δ<i>H</i>^⧧ = 15.0(2) kcal mol^–1; and Δ<i>S</i>^⧧ = −4.2(7) eu. DFT studies support the experimentally measured rotation activation energy (cf. calculated Δ<i>H</i>^⧧ = 11.1 kcal mol^–1) as well as the presence of a high-energy triplet intermediate (Δ<i>H</i> = 8.8 kcal mol^–1)

The Chemistry of CO2 Capture in an Amine-Functionalized Metal-Organic Framework under Dry and Humid Conditions.

The use of two primary alkylamine functionalities covalently tethered to the linkers of IRMOF-74-III results in a material that can uptake CO2 at low pressures through a chemisorption mechanism. In contrast to other primary amine-functionalized solid adsorbents that uptake CO2 primarily as ammonium carbamates, we observe using solid state NMR that the major chemisorption product for this material is carbamic acid. The equilibrium of reaction products also shifts to ammonium carbamate when water vapor is present; a new finding that has impact on control of the chemistry of CO2 capture in MOF materials and one that highlights the importance of geometric constraints and the mediating role of water within the pores of MOFs

The chemistry of CO2 capture in an amine-functionalized metal-organic framework under dry and humid conditions

The use of two primary alkylamine functionalities covalently tethered to the linkers of IRMOF-74-III results in a material that can uptake CO2 at low pressures through a chemisorption mechanism. In contrast to other primary amine-functionalized solid adsorbents that uptake CO2 primarily as ammonium carbamates, we observe using solid state NMR that the major chemisorption product for this material is carbamic acid. The equilibrium of reaction products also shifts to ammonium carbamate when water vapor is present; a new finding that has impact on control of the chemistry of CO2 capture in MOF materials and one that highlights the importance of geometric constraints and the mediating role of water within the pores of MOFs.Fil: Flaig, Robinson W.. University of California at Berkeley; Estados UnidosFil: Osborn Popp, Thomas M.. University of California at Berkeley; Estados UnidosFil: Fracaroli, Alejandro Matías. University of California at Berkeley; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Kapustin, Eugene A.. University of California at Berkeley; Estados UnidosFil: Kalmutzki, Markus J.. University of California at Berkeley; Estados UnidosFil: Altamimi, Rashid M.. King Abdulaziz City for Science and Technology; Arabia SauditaFil: Fathieh, Farhad. University of California at Berkeley; Estados UnidosFil: Reimer, Jeffrey A.. University of California at Berkeley; Estados Unidos. Lawrence Berkeley National Laboratory; Estados UnidosFil: Yaghi, Omar M.. University of California at Berkeley; Estados Unidos. King Abdulaziz City for Science and Technology; Arabia Saudit

Carbon Dioxide Capture Chemistry of Amino Acid Functionalized Metal-Organic Frameworks in Humid Flue Gas

Metal-organic framework-808 has been functionalized with 11 amino acids (AA) to produce a series of MOF-808-AA structures. The adsorption of CO2 under flue gas conditions revealed that glycine- and DL-lysine-functionalized MOF-808 (MOF-808-Gly and -DL-Lys) have the highest uptake capacities. Enhanced CO2 capture performance in the presence of water was observed and studied using single-component sorption isotherms, CO2/H2O binary isotherm, and dynamic breakthrough measurements. The key to the favorable performance was uncovered by deciphering the mechanism of CO2 capture in the pores and attributed to the formation of bicarbonate as evidenced by 13C and 15N solid-state nuclear magnetic resonance spectroscopy studies. Based on these results, we examined the performance of MOF-808-Gly in simulated coal flue gas conditions and found that it is possible to capture and release CO2 by vacuum swing adsorption. MOF-808-Gly was cycled at least 80 times with full retention of performance. This study significantly advances our understanding of CO2 chemistry in MOFs by revealing how strongly bound amine moieties to the MOF backbone create the chemistry and environment within the pores, leading to the binding and release of CO2 under mild conditions without application of heat

The Chemistry of CO₂ Capture in an Amine-Functionalized Metal–Organic Framework under Dry and Humid Conditions

The use of two primary alkylamine functionalities covalently tethered to the linkers of IRMOF-74-III results in a material that can uptake CO₂ at low pressures through a chemisorption mechanism. In contrast to other primary amine-functionalized solid adsorbents that uptake CO₂ primarily as ammonium carbamates, we observe using solid state NMR that the major chemisorption product for this material is carbamic acid. The equilibrium of reaction products also shifts to ammonium carbamate when water vapor is present; a new finding that has impact on control of the chemistry of CO₂ capture in MOF materials and one that highlights the importance of geometric constraints and the mediating role of water within the pores of MOFs