Mixed anionic and inclusion complexes of nickel(II) with nitroaromatics showing selectivity in oxygen-π interactions

Shankar, Krapa; Baruah, Jubaraj B.

doi:10.1016/j.ica.2016.08.017

Cited by 10 publications

(11 citation statements)

References 60 publications

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“…This interaction causes quenching of fluorescence. [23] Whereas, complex 5 had lower emission than complex 2 but complex 6 and 7 were higher than complex 2 (Figure S13b). These can be easily explained through CÀH…p interactions in 5, which reduce intensity of emissions, whereas bigger anion in these complexes helped to keep tetranuclear cations apart causing enhancement of fluorescence.…”

Section: Resultsmentioning

confidence: 95%

“…Quinone type structure of 2-or 4nitrophenol in solution prevented formation of exciplex by selfinteractions between phenolic and quinonic forms. Generally, p-stacking and anion-p interactions [10] and oxygen…p interactions [23] cause fluorescence quenching. In the structure of nitrophenol containing complexes interactions between nitrophenols with fluorophores were observed hence fluorescence quenching were result of such interactions in solid state.…”

Section: Resultsmentioning

confidence: 99%

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Tetranuclear Cobalt Complexes as Nano-Dimensional Template for Inclusion of Nitrophenols

Shankar

Baruah

2016

ChemistrySelect

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Htea = dianion of triethanolamine, bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) having tetranuclear cations with end to end distance~1.69 nm and~1.62 nm respectively were characterized. These complexes are weakly fluorescent in sol-ution and fluorescence of respective complexes decreases upon interactions with nitrophenols. Complexes from reactions of 1 and 2 with nitrophenols were isolated and structurally characterized. They also show lower fluorescence in solid state than respective parent complex due to oxygen-p interactions. Complex 2 underwent cation exchange to form new tetranuclear oxido cobalt complexes possessing [MCl 4 ] 2À ( M= Zn or Cd) anion.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Tetranuclear Cobalt Complexes as Nano-Dimensional Template for Inclusion of Nitrophenols

Shankar

Baruah

2016

ChemistrySelect

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“…Many nitroaromatic compounds are toxic; 78 hence, their detections at low concentrations by abundant nontoxic metal ions may have utility. 18 Thus, it is necessary to differentiate the ability of detection of nitroaromatic compounds by the nontoxic zinc complex over the cadmium complex as cadmium ions are generally toxic. Furthermore, the zinc–salicylaldimine complex is able to detect nitroaromatics through photoluminescence quenching.…”

Section: Resultsmentioning

confidence: 99%

“…79 The examples of small metal complexes to do so are relatively less. 15−18 The fluorescence active zinc complex 2 as well as the cadmium complex 5 are structurally simple; they are easily synthesized. In an earlier study, we found that self-assembly of a molecular nickel complex was formed by weak interactions of a free pyridine molecule to hold multiple dissimilar nickel complexes.…”

Section: Resultsmentioning

confidence: 99%

Copper(II), Zinc(II), and Cadmium(II) Formylbenzoate Complexes: Reactivity and Emission Properties

2019

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Synthesis, characterization, reactivity, and sensing properties of 4-formylbenzoate complexes of copper(II), zinc(II), and cadmium(II) possessing the 1,10-phenanthroline ancillary ligand are studied. The crystal structures of the (1,10-phenanthroline)bis(4-formylbenzoate)(aqua)copper(II) and (1,10-phenanthroline)bis(4-formylbenzo-ate)zinc(II) and a novel molecular complex comprising an assembly of mononuclear and dinuclear species of (1,10-phenanthroline)bis(4-formylbenzoate)cadmium(II) are reported. These zinc and cadmium complexes are fluorescent; they show differentiable sensitivity to detect three positional isomers of nitroaniline. The mechanism of sensing of nitroanilines by 1,10-phenanthroline and the complexes are studied by fluorescence titrations, photoluminescence decay, and dynamic light scattering. A plausible mechanism showing that 1,10-phenanthroline ligand-based emission quenched by electron transfer from the excited state of 1,10-phenanthroline to nitroaniline is supported by density functional theory calculations. In an anticipation to generate a fluorescent d10-copper(I) formylbenzoate complex by a mild reducing agent such as hydroxylamine hydrochloride for similar sensing of nitroaromatics as that of the d10-zinc and cadmium 4-formylbenzoate complexes, reactivity of d9-copper(II) with hydroxylamine hydrochloride in the presence of 4-formylbenzoic acid and 1,10-phenanthroline is studied. It did not provide the expected copper(I) complex but resulted in stoichiometry-dependent reactions of 4-formylbenzoic acid with hydroxylamine hydrochloride in the presence of copper(II) acetate and 1,10-phenanthroline. Depending on the stoichiometry of reactants, an inclusion complex of bis(1,10-phenanthroline)(chloro)copper(II) chloride with in situ-formed 4-((hydroxyimino)methyl)benzoic acid or copper(II) 4-(hydroxycarbamoyl)benzoate complex was formed. The self-assembly of the inclusion complex has the bis(1,10-phenanthroline)(chloro)copper(II) cation encapsulated in hydrogen-bonded chloride-hydrate assembly with 4-((hydroxyimino)methyl)benzoic acid.

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“…The strength of associations with guests and kinetics of delivery caters to understand transport and delivery of guests. Identification of stable host-assemblies from which guest can be easily removed, [143][144][145][146][147][148] search for new templates for molecular recognitions, [149][150][151][152][153] self-assembling leading to properties such as gelation, 154 will continue to be challenges. Host-guest assemblies with comparable sizes and their recognition of, for example, C 60 as guest included in metal-porphyrin 155,156 for photochemical conversion have future ahead.…”

Section: Outlook and Conclusionmentioning

confidence: 99%

Predominantly ligand guided non-covalently linked assemblies of inorganic complexes and guest inclusions

Baruah

2018

J Chem Sci

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Various non-covalently linked inorganic self-assemblies formed by the supramolecular interacting sites located at the ligands are discussed. The impetus for this rapidly growing topic on the construction of robust assemblies is elucidated by select examples that are associated with interesting structures and properties. The review includes discussion on the stabilization of different assemblies of nucleobases in the non-covalent assemblies of inorganic complexes. The participation of the guest molecules in the formation of self-assemblies with hosts to make extra space or voids for intake of the guest, water-assisted assemblies, changes in the structures guided by cations, and aggregation-induced photoluminescence in the self-assemblies of metal complexes are presented. Fine-tuning of non-covalent self-assemblies of metal complexes by changing ligands or by other components, which modify the guest recognition abilities is elucidated. The discussions are based on selected examples of self-assemblies that use supramolecular features of peripheral part of ligands or ligand of a complex that helps one to identify templates for weak interactions and for molecular recognition.

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Mixed anionic and inclusion complexes of nickel(II) with nitroaromatics showing selectivity in oxygen-π interactions

Cited by 10 publications

References 60 publications

Tetranuclear Cobalt Complexes as Nano-Dimensional Template for Inclusion of Nitrophenols

Tetranuclear Cobalt Complexes as Nano-Dimensional Template for Inclusion of Nitrophenols

Copper(II), Zinc(II), and Cadmium(II) Formylbenzoate Complexes: Reactivity and Emission Properties

Predominantly ligand guided non-covalently linked assemblies of inorganic complexes and guest inclusions

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