Tetrakis(diisopropyl amide) substituted norbornadiene and quadricyclane are highly barium selective ligands

Abstract

Tetrakis(diisopropyl amide) substituted norbornadiene and quadricyclane derivatives were investigated for their extraction and transport capabilities with alkaline earth metal cations. Both amides exhibited a remarkably high preference of Ba 2+ over any other alkali metal or alkaline earth cation. The binding geometries were determined by quantum chemical DFT calculations.

Photodeactivation paths in norbornadiene

“…[8] and [9]. It should be pointed out that the reaction has other new fields of application, besides energy storage, such as creating molecular switches or photochromic chemosensors and carriers for metal cations . Theoretical investigations of norbornadiene photoisomerization have been restricted to the determination of strain energy in different norbornadiene/quadricyclane derivatives, as predicted by the DFT calculations of the reaction enthalpies.…”

“…It should be pointed out that the reaction has other new fields of application, besides energy storage, such as creating molecular switches [10,11] or photochromic chemosensors and carriers for metal cations. [12] Theoretical investigations of norbornadiene photoisomerization have been restricted to the determination of strain energy [13] in different norbornadiene/ quadricyclane derivatives, as predicted by the DFT calculations of the reaction enthalpies. Furthermore, a barrier for the conversion between norbornadiene and quadricyclane cation radicals has been calculated at the PMP4//MP2/6-31G* and CCSD(T)// MP2/6-31G* levels of theory.…”

7-Isopropylidene-N2,N3,N5,N6-tetramethoxy-N2,N3,N5,N6-tetramethylbicyclo[2.2.1]hepta-2,5-diene-2,3,5,6-tetracarboxamide

“…For background to this work, see: Winkler et al (2003aWinkler et al ( , 2012. For the structure of 7-isopropylidenenorborna-2,5-diene-2,3,5,6-tetracarboxylic acid tetrakis(diethylamide), see: Winkler et al (2003b).…”

“…The tertiary tetra amides of norbornadiene and quadricyclane are interesting compounds because of their ability to form stable complexes with alkali and alkaline earth metal cations. (Winkler et al, 2003a;Winkler et al, 2012) To enable further synthetic modifications, the tetrakis(N,O-dimethylhydroxyl amide) was synthesized. For the identification of this compound, a structure determination was performed.…”

Alkaline and alkaline earth metals

“…124 The characterisation of Ba trichloroacetate adduct compounds has been reported and tetrakis(diisopropylamide)-substituted norbornadiene and quadricyclane have been reported as highly selective ligands for the same alkaline earth metal. 125,126 A calcium-catalysed reduction of propargylic alcohols and ethers has been accomplished by using triethylsilane as a nucleophilic hydride source. 127 A cationic calcium hydride cluster stabilised by cyclen-derived macrocyclic ligands has been described and shown to be active for the hydrosilylation of alkenes.…”