2794-60-7Relevant articles and documents
Pyridyldiimine macrocyclic ligands: Influences of template ion, linker length and imine substitution on ligand synthesis, structure and redox properties
Thierer, Laura M.,Wang, Qiuran,Brooks, Sam H.,Cui, Peng,Qi, Jia,Gau, Michael R.,Manor, Brian C.,Carroll, Patrick J.,Tomson, Neil C.
, (2021)
A series of 2,6-diiminopyridine-derived macrocyclic ligands have been synthesized via [2 + 2] condensation around alkaline earth metal triflate salts. The inclusion of a tert-butyl group at the 4-position of the pyridine ring of the macrocyclic synthons results in macrocyclic complexes that are soluble in common organic solvents, thereby enabling a systematic comparison of the physical properties of the complexes by NMR spectroscopy, mass spectrometry, solution-phase UV–Vis spectroscopy, cyclic voltammetry and single-crystal X-ray crystallography. Solid-state structures determined crystallographically demonstrate increased twisting in the ligand, concurrent with either a decrease in ion size or an increase in macrocycle ring size (18, 20, or 22 membered rings). The degree of folding and twisting within the macrocycle can be quantified using parameters derived from the Npyr-M-Npyr bond angle and the relative orientation of the pyridinediimine (PDI) and pyridinedialdimine (PDAI) fragments to each other within the solid state structures. Cyclic voltammetry and UV–Vis spectroscopy were used to compare the relative energies of the imine π* orbital of the redox active PDI and PDAI components in the macrocycle when coordinated to redox inactive metals. Both methods indicate the change from a methyl to hydrogen substitution on the imine carbon lowers the energy of the ligand π* system.
A Novel High-yield Route to Organic Derivatives of Group 2 Metals; X-Ray Structure of 4(py)14>*py (OTf = OSO2CF3) and NMR Spectral Characterisation of (R = SiMe3)
Frankland, Andrew D.,Hitchcock, Peter B.,Lappert, Michael F.,Lawless, Gerard A.
, p. 2435 - 2436 (1994)
Treatment of M(OTf)2 with 2 MOAr or 2 MNR2 (M = Na or K, Ar = C6H2But2-2,6-Me-4; R = SiMe3) in thf at 0 deg C affords 4, (M = Sr 5 or Ba 6), (M = Ca 7 or Sr 8) or 9; the new compounds 1-3 have been characterised by their NMR spectra in pyridine, and the pyridine adduct of 3 also by X-ray diffraction: crystalline 2-OTf)2(μ-OTf)2(μ3-OTf)4(py)14>*py 10 is unique among metal triflates in having three different bonding modes for the -OTf ligand.
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Hedwig, G. R.,Parker, A. J.
, p. 6589 - 6593 (1974)
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Molecular recognition of barbiturates by a metalloreceptor
Doorn, Arie R. van,Rushton, David J.,Straaten-Nijenhuis, Wilma F. van,Verboom, Willem,Reinhoudt, David N.
, p. 421 - 426 (2007/10/02)
Metallomacrocycle 2, possessing an immobilized Lewis-acidic uranyl cation, was synthesized by reaction of aldehyde 9 with 1,2-cis-cyclohexanediamine in the presence of Ba(2+) as a template cation and subsequent transmetallation with UO2(2+).Docking experiments with barbituric acid revealed that a -(CH2)6- spacer between the salen-uranyl and 2,6-diamidopyridine moieties of 2 is optimal.According to 1H-NMR titration experiments, the barbituric acid complex of 2 is up to 2.7 kcal*mol-1 more stable than the complexes with five disubstituted derivatives.The flux of barbbituric acid through a supported liquid membrane is enhanced 3.7 times by carrier 2 mediated transport.
