Improved synthesis of functionalized mesogenic 2,6-bisbenzimidazolylpyridine ligands

McKenzie, Blayne M.; Miller, Adriane K.; Wojtecki, Rudy J.; Johnson, J. Casey; Burke, Kelly A.; Tzeng, Karis A.; Mather, Patrick T.; Rowan, Stuart J.

doi:10.1016/j.tet.2008.05.075

Cited by 32 publications

(33 citation statements)

References 52 publications

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“…creasings ize R = H( L4) < R = CH 3 (L5) < R = CH 2 CH 3 (L6)t o preventa ny infiltrationo fi nner-spheres olventm olecules and/ or counter-anions into the core of the target [Ln(Lk) 3 ] 3 + triple helices.T he syntheses of the bis-benzimidazolpyridine series (bisbzimpy: L4-L6)r ely on the well-established two-stepr eductive Philips-modified reactiono fa ctivatedd ipicolinic acid 7 with substituted ortho-nitroaminophenyl derivatives 5a-c. [32] The synthesis of L4,w hich used commercially available 5a, was reported previously. [28,30] Analogous 5-methyl derivatives 5b and the 5-ethyl derivative 5c can be obtained easily by aryl nucleophilic substitution of adapted ortho-bromo-nitrophenyls 1 and 4, [33] thus leadingt oligands L5 and L6 (Scheme 3).…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic Programming of Erbium(III) Coordination Complexes for Dual Visible/Near‐Infrared Luminescence

Golesorkhi

Guénée

Nozary

et al. 2018

Chemistry A European J

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Intrigued by the unexpected room-temperature dual visible/near-infrared (NIR) luminescence observed for fast-relaxing erbium complexes embedded in triple-stranded helicates, in this contribution, we explore a series of six tridentate N-donor receptors L4-L9 with variable aromaticities and alkyl substituents to extricate the stereoelectronic features responsible for such scarce optical signatures. Detailed solid-state (X-ray diffraction, differential scanning calorimetry, optical spectroscopy) and solution (speciations and thermodynamic stabilities, spectrophotometry, NMR and optical spectroscopy) studies of mononuclear unsaturated [Er(Lk) ] and saturated triple-helical [Er(Lk) ] model complexes reveal that the stereoelectronic changes induced by the organic ligands affect inter- and intramolecular interactions to such an extent that 1) melting temperatures in solids, 2) the affinity for trivalent erbium in solution, and 3) optical properties in luminescent complexes can be rationally varied and controlled. With this toolkit in hand, mononuclear erbium complexes with low stabilities displaying only NIR emission can be transformed into molecular-based dual Er-centered visible/NIR emitters operating at room temperature in both solid and solution states.

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Section: Resultsmentioning

confidence: 99%

Thermodynamic Programming of Erbium(III) Coordination Complexes for Dual Visible/Near‐Infrared Luminescence

Golesorkhi

Guénée

Nozary

et al. 2018

Chemistry A European J

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“…The synthesis of the BIP ligand was accomplished in two steps following established literature protocols. The methoxy‐protected BIP ligand was prepared by a one‐pot process similar to the protocol developed by McKenzie et al, where Na 2 S 2 O 4 is used in the final step to reduce the NO 2 group to amine to effect transformation to the bisbenzimidazole ( 5 ). Initial attempts to deprotect the methoxy groups with BBr 3 led to the formation of a bis‐bromomethyl product rather than the desired bis‐hydroxymethyl ( 6 ).…”

Section: Resultsmentioning

confidence: 99%

Metallo‐supramolecular Crosslinked Polyurethanes

Lambeth

Morgan

Savage

et al. 2019

J Polym Sci B Polym Phys

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The effects of incorporating metal‐binding ligands as chain extenders in polyurethane elastomers were investigated. Segmented polyurethanes based on 2 kDa poly(tetramethylene oxide) (PTMO) and 4,4‐methylenebis(cyclohexyl isocyanate) were polymerized using a two‐step process in which 2,6‐bis(1‐ethyl‐5‐(methoxymethyl)‐1H‐benzo[d]imidazol‐2‐yl)pyridine was added as a chain extender. The resulting polyurethanes were then metallated using stoichiometric amounts of Zn(II) metal salts with different counterions. The resulting metallopolymers have substantially improved Young's moduli, increased failure stress, and improved thermomechanical behavior. The materials were microphase‐separated into anisotropic hard domains within a PTMO matrix. Simultaneous small‐angle X‐ray scattering and tensile testing revealed the minority hard segment domains remain relatively intact during elongation, likely due to the strength of the metal–ligand complex. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1744–1757

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“…Chart 1 shows the three known reference ligands HR1-HR3 [23,29]. New 2,4,6-trisubstituted pyridine P2 was obtained by monooxidation of bis-methanol 3 (itself prepared from chelidamic acid in three multi-gram steps by modified literature procedures [5][6][7][30][31][32]) with SeO 2 in dioxane (Scheme 3) [12]. Until now, only one report described an analogue of P2 as a by-product of bis-oxidation of a substituted bis-methanol-pyridine by SeO 2 [33].…”

Section: Resultsmentioning

confidence: 99%

Synthesis and spectroscopy of anionic tridentate benzimidazole-pyridine carboxylate and tetrazolate chromophore ligands

Shavaleev

Eliseeva

2015

Inorganica Chimica Acta

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Improved synthesis of functionalized mesogenic 2,6-bisbenzimidazolylpyridine ligands

Cited by 32 publications

References 52 publications

Thermodynamic Programming of Erbium(III) Coordination Complexes for Dual Visible/Near‐Infrared Luminescence

Thermodynamic Programming of Erbium(III) Coordination Complexes for Dual Visible/Near‐Infrared Luminescence

Metallo‐supramolecular Crosslinked Polyurethanes

Synthesis and spectroscopy of anionic tridentate benzimidazole-pyridine carboxylate and tetrazolate chromophore ligands

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