Organomagnesium Crown Ethers and Their Binding Affinities with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ Ions - a Theoretical Study

Abstract

Novel organomagnesium crown ether molecules have been computationally characterized for the first time using density functional theory (DFT). Monomer units of MgC6 have been used as building blocks. The potential energy surface of the parent elemental composition, MgC6H2, has been extensively explored using both DFT and coupled-cluster methods. It is concluded that the seven-membered ring isomer, 1-magnesacyclohept-4-en-2,6-diyne, is the thermodynamically most stable molecule at all levels. Thus, the latter has been used as the building block for organomagnesium crown ethers. Both alkali (Li+, Na+, and K+) and alkaline-earth (Be2+, Mg2+, and Ca2+) metal ions selective complexes have been theoretically identified. Binding energies (Delta E at 0 K) and thermally corrected Gibbs free energies (Delta G at 298.15 K) have<br>been computed for these metal ions with MgC6-9-crown-3 and MgC6-12-crown-4 to gauge their binding affinities.Novel organomagnesium crown ether molecules have been computationally characterized for the first time using density functional theory (DFT). Monomer units of MgC6 have been used as building blocks. The potential energy surface of the parent elemental composition, MgC6H2, has been extensively explored using both DFT and coupled-cluster methods. It is concluded that the seven-membered ring isomer, 1-magnesacyclohept-4-en-2,6-diyne, is the thermodynamically most stable molecule at all levels. Thus, the latter has been used as the building block for organomagnesium crown ethers. Both alkali (Li+, Na+, and K+) and alkaline-earth (Be2+, Mg2+, and Ca2+) metal ions selective complexes have been theoretically identified. Binding energies (Delta E at 0 K) and thermally corrected Gibbs free energies (Delta G at 298.15 K) have been computed for these metal ions with MgC6-9-crown-3 and MgC6-12-crown-4 to gauge their binding affinities.

Organomagnesium Crown Ethers and Their Binding Affinities with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ Ions – A Theoretical Study

“…[14] The ability of crown ethers to recognize and trap different metal ions depending on the size of the macrocyclic ring, type of the donor atom (N, O, and S and thus hard-soft interactions), and polarity of the medium strengthened their utility in various aspects. [15][16][17][18][19][20] Various isomers of MgC 6 H 2 have been extensively explored by Thimmakondu and co-workers, in a previous theoretical study, using density functional theory (DFT) and coupledcluster methods. [21] The thermodynamically most stable isomer for MgC 6 H 2 was identified to be 1-magnesacyclohept-4-en-2,6diyne.…”