Synthesis, stereocontrol and structural studies of highly luminescent chiral tris-amidepyridyl-triazacyclononane lanthanide complexes

Abstract

(2014) 'Synthesis, stereocontrol and structural studies of highly luminescent chiral tris-amidepyridyl-triazacyclononane lanthanide complexes. ', Dalton transactions., 43 (14). pp. 5490-5504. Further information on publisher's website:http://dx.doi.org/10.1039/C3DT53000KPublisher's copyright statement: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The configuration of the remote amide chiral moiety determines the helicity of the metal complex in Ln(III) complexes of nonadentate N 6 O 3 ligands based on triazacyclononane. Solution NMR studies revealed the presence of a dominant isomer whose proportion varies from 9:1 to 4:1 from Ce to Yb and X-Ray crystallographic studies at 120K of the Yb and two enantiomeric Eu complexes confirmed the configuration as S-in the major isomer. Global minimisation methods allowed magnetic susceptibility and electronic relaxation times of the lanthanide ions to be estimated by analysis of variable field longitudinal relaxation rate (R 1 ) data sets. A set of four europium complexes, containing different para-substituted pyridinyl-aryl groups, exist as one major isomer (15:1), absorb light strongly via an ICT transition in the range 320 to 355 nm ( = 55 to 65,000 M -1 cm -1 ). The two examples absorbing light at 332 nm, possess overall emission quantum yields of 35 and 37% in aereated water, making these systems as bright as any Eu complex in solution.

Synthesis of meta and para-substituted aromatic sulfonate derivatives of polydentate phenylazaphosphinate ligands: enhancement of the water solubility of emissive europium(iii) EuroTracker® dyes

“…13,15,16 These structural studies also confirmed that the phosphorus-oxygen double bond lies out of the plane of the aryl rings. A simple retrosynthetic analysis suggests the intermediacy of a 2,4,6-trisubstituted pyridine, with a 4-Br group, allowing a Sonogashira coupling reaction to an arylalkyne in a final ligand assembly step.…”

“…the P centres respectively, as deduced by X-ray and CD studies on related systems. [13][14][15][16] OBC 2014 Delbianco 3…”

“…the P centres respectively, as deduced by X-ray and CD studies on related systems. [13][14][15][16] In order to form the C-P bond, a palladium-catalysed reaction was envisaged, allowing insertion of a 2-pyridyl group into the P-H bond of a phenylphosphinic ester, bearing a suitably protected sulfonate group. Following the studies of Miller, 6a the behaviour of the trifluoroethyl and phenylsulfonate esters as protecting groups for the sulfonic acid moiety was examined; each ester was derived from 3 or 4-bromo-phenylsulfonyl chloride (Scheme 1).…”

“…The Eu(III) complexes show good water solubility and possess a brightness, B (340 nm) in water of between 17 and 20 mM -1 cm -1 , making them amongst the most emissive europium complexes in aqueous solution. [13][14][15] …”

Lanthanide light for biology and medical diagnosis

“…For instance, brightness in the range 20 000-30 000 M -1 cm -1 has recently been achieved in aqueous solution for Eu III complexes [22]. Scheme 1.…”