Comparative studies of the electronic, binding and photophysical properties of a new nona-dentate hemi-cage tripodal HQ pendant trizaza-macrocycle with unfilled, half-filled and completely filled lanthanide ions

Rohini,; Baral, Minati; Kanungo, B. K.

doi:10.1039/c8nj02217h

Cited by 9 publications

(2 citation statements)

References 54 publications

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“…Thus lanthanide compounds are believed to have very little, or almost no covalent nature and thus are held together with a mild omni-directional electrostatic force of attraction. [42] 3.6. Bonding behavior of metal complexes…”

Section: Molecular Geometry Prediction Of Lanthanide Complexesmentioning

confidence: 99%

Development of a Flexible Tripodal Hydroxypyridinone Ligand with Cyclohexane Framework: Complexation, Solution Thermodynamics, Spectroscopic and DFT Studies

2021

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Conformationally flexible ligands of appropriate size and denticity can wrap to a metal ion with high stability. In this perspective, a new tripodal siderophore‐mimic hexadentate chelator, N‐[3,5‐bis[(1‐hydroxy‐6‐oxo‐pyridine‐2‐carbonyl)amino]cyclohexyl]‐1‐hydroxy‐6‐oxo‐pyridine‐2‐carboxamide, (TACH‐1,2‐HOPO), which contains three 1,2‐hydroxypyridinone units attached to a cyclohexane ring through amide linkage at 1,3 and 5 positions, has been designed and synthesized. The characterization of the ligand was carried out through various techniques like FT‐IR, 1H NMR, 13C NMR, ESI‐MS, and electronic spectroscopy. In an aqueous medium, the solution thermodynamics and photophysical properties of the chelator and its La3+, Gd3+, and Lu3+ complexes were determined experimentally as well as theoretically. The pKa values for the ligand were found to be 8.40, 5.74, and 5.39. Formation of lanthanide complexes of type MLH3, MLH2, MLH, ML, and ML.(H2O)x (x=1,2 and 3) was perceived, and the log βmlh for various partially and fully protonated and hydrated lanthanide complexes are reported. Theoretical calculations by DFT supported the experimental results. The experimentally determined protonation constants gave the same trend of ΔG0 values obtained by DFT; also, the theoretically calculated FT‐IR, 1H, 13C NMR, electronic, and excitation spectral data are in covenant with experimental findings. The bonding behavior between the lanthanide ions and the TACH‐1,2‐HOPO explicated by implication of NBO, Morokuma Ziegler energy decomposition analysis (ETS‐NOCV), propose the Ln−L bonds are less covalent with the trend Lu>Gd>La.

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Section: Molecular Geometry Prediction Of Lanthanide Complexesmentioning

confidence: 99%

Development of a Flexible Tripodal Hydroxypyridinone Ligand with Cyclohexane Framework: Complexation, Solution Thermodynamics, Spectroscopic and DFT Studies

2021

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“…In nature, the variety of the amino acid side chains is the key for protein to realize the recognition of small molecules and thereby access the corresponding bio-functions, such as carbohydrate protein [ 1 , 2 , 3 ] and sortase transpeptidases [ 4 , 5 , 6 ]. Inspired by nature, large amount of artificial molecules or complexes were synthesized to structurally or functionally mimic functional protein, for instance, foldamers [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ], macrocycles [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ], cages [ 23 , 24 , 25 , 26 , 27 ], hemicagepodates [ 28 , 29 , 30 , 31 , 32 ], etc. Wherein, macrocycles represent one of the most popular mimics.…”

Section: Introductionmentioning

confidence: 99%

Recognition Site Modifiable Macrocycle: Synthesis, Functional Group Variation and Structural Inspection

Fan

Kong

et al. 2023

Molecules

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Traditional macrocyclic molecules encode recognition sites in their structural backbones, which limits the variation of the recognition sites and thus, would restrict the adjustment of recognition properties. Here, we report a new oligoamide-based macrocycle capable of varying the recognition functional groups by post-synthesis modification on its structural backbone. Through six steps of common reactions, the parent macrocycle (9) can be produced in gram scale with an overall yield of 31%. The post-synthesis modification of 9 to vary the recognition sites are demonstrated by producing four different macrocycles (10–13) with distinct functional groups, 2-methoxyethoxyl (10), hydroxyl (11), carboxyl (12) and amide (13), respectively. The 1H NMR study suggests that the structure of these macrocycles is consistent with our design, i.e., forming hydrogen bonding network at both rims of the macrocyclic backbone. The 1H-1H NOESY NMR study indicates the recognition functional groups are located inside the cavity of macrocycles. At last, a preliminary molecular recognition study shows 10 can recognize n-octyl-β-D-glucopyranoside (14) in chloroform.

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Computational and experimental studies on the effect of conformational flexibility on bonding and photophysics of a triaza-macrocycle tripod

Verma

Baral

Kanungo

2021

J Incl Phenom Macrocycl Chem

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Comparative studies of the electronic, binding and photophysical properties of a new nona-dentate hemi-cage tripodal HQ pendant trizaza-macrocycle with unfilled, half-filled and completely filled lanthanide ions

Abstract: The present paper describes the comparative studies of the electronic, photophysical and binding properties of a new C3-symmetric polydentate ligand and its complexes with 4f0, 4f7, and 4f14 metal ions (La3+, Gd3+, and Lu3+).

Cited by 9 publications

References 54 publications

Development of a Flexible Tripodal Hydroxypyridinone Ligand with Cyclohexane Framework: Complexation, Solution Thermodynamics, Spectroscopic and DFT Studies

Development of a Flexible Tripodal Hydroxypyridinone Ligand with Cyclohexane Framework: Complexation, Solution Thermodynamics, Spectroscopic and DFT Studies

Recognition Site Modifiable Macrocycle: Synthesis, Functional Group Variation and Structural Inspection

Computational and experimental studies on the effect of conformational flexibility on bonding and photophysics of a triaza-macrocycle tripod

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