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            C NMR study of paramagnetic chiral macrocyclic lanthanide complexes

Lisowski, Jerzy

doi:10.1002/(sici)1097-458x(199904)37:4<287::aid-mrc455>3.0.co;2-#

Cited by 36 publications

(2 citation statements)

References 30 publications

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“…39 In the presence of a lanthanide metal ion template, with either amine, [2+2]-lanthanide complexes are formed, and these have been studied extensively. [40][41][42][43][44][45][46] Additionally, the isolated meso-[2+2], incorporating both R,Rand S,S-cyclohexyl moieties, can be reacted with excess CdCl2 to afford rearrangement into a [6+6]cadmium complex. 47,48 As such, 2,6-diformylpyridine is a simple building block that can be exploited with a degree of control to create a complex dynamic combinatorial library or to isolate specific species.…”

Section: Introductionmentioning

confidence: 99%

Dynamic and solid-state behaviour of bromoisotrianglimine

Scholes,

Kershaw-Cook,

Szczypiński

et al. 2023

Preprint

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Solid-state materials formed from discrete imine macrocycles have potential in industrial separations, but dynamic behaviour during both synthesis and crystallisation makes them challenging to exploit. Here, we explore opportunities for structural control by investigating the dynamic nature of a C-5 brominated isotrianglimine in solution and under crystallisation conditions. In solution, the equilibrium between the [3+3] and the less reported [2+2] macrocycle was investigated, and both macrocycles were fully characterised. Solvent templating during crystallisation was used to form new packing motifs for the [3+3] macrocycle and an unreported [4+4] macrocycle. Finally, chiral self-sorting was used to demonstrate how crystallisation conditions can not only influence packing arrangements but also shift the macrocycle equilibrium to yield new structures. This work thus exemplifies three strategies for exploiting dynamic behaviour to form isotrianglimine materials, and highlights the importance of understanding the dynamic behaviour of a system when designing and crystallising functional materials formed using dynamic covalent chemistry.

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Section: Introductionmentioning

confidence: 99%

Dynamic and solid-state behaviour of bromoisotrianglimine

Scholes,

Kershaw-Cook,

Szczypiński

et al. 2023

Preprint

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“…Whitesides and Lewis introduced the tris(camphorato) europium(III) complex as the first chiral lanthanide shift reagent. 20 On the other hand, more elaborate lanthanide complexes with chiral crown ether derivatives, 21,22 a chiral macrocyclic nitrogendonor ligand, 23 and pendant aminocyclodextrin hosts 24,25 were devised. Aqueous lanthanide(III) shift reagents were also extensively developed by using multidentate amine derivative ligands [7][8][9][10][11][12][13][14][15][16][17][18] and simple bidentate α-hydroxycarboxylates 19 and L-tartarate.…”

Section: Introductionmentioning

confidence: 99%

Enantiomeric NMR signal separation behavior and mechanism of samarium(III) and neodymium(III) complexes with (S,S)‐ethylenediamine‐N,N'‐disuccinate

2017

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Enantiomeric H and C NMR signal separation behaviors of various α-amino acids and DL-tartarate were investigated by using the samarium(III) and neodymium(III) complexes with (S,S)-ethylenediamine-N,N'-disuccinate as chiral shift reagents. A relatively smaller concentration ratio of the lanthanide(III) complex to substrates was suitable for the neodymium(III) complex compared with the samarium(III) one, striking a balance between relatively greater signal separation and broadening. To clarify the difference in the signal separation behavior, the chemical shifts of β-protons for fully bound D- and L-alanine (δ (D) and δ (L)) and their adduct formation constants (Ks) were obtained for both metal complexes. Preference for D-alanine was similarly observed for both complexes, while it was revealed that the difference between the δ (D) and δ (L) values is the significant factor to determine the enantiomeric signal separation. The neodymium(III) and samarium(III) complexes can be used complementarily for higher and smaller concentration ranges of substrates, respectively, because the neodymium(III) complex gives the larger difference between the δ (D) and δ (L) values with greater signal broadening compared to the samarium(III) complex.

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