Zinc acetylacetonate hydrate adducted with nitrogen donor ligands: Synthesis, spectroscopic characterization, and thermal analysis

Brahma, Sanjaya; Shivashankar, S. A.

doi:10.1016/j.molstruc.2015.07.075

Cited by 14 publications

(13 citation statements)

References 41 publications

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“…In the anisothermal region, after a slight particle rearrangement step in the first 60 s, an abrupt shrinkage is observed up to the maximum temperatures applied (100 and 140 °C) for all the samples. At approximatively 200 s, which corresponds to the temperature of 80 °C, ZnAA loses its structural water. − The inflexion point observed in the shrinkage curve (Figure a) may be associated with this phenomenon, as the thermal energy supplied by the evaporation process is consumed by the system . In the case of ZnO-140B, during the 120 min dwell, the sample further densifies at a strain rate (ε̇) of 9.8 × 10 –4 s –1 for approximatively 45 s (Supporting Information, Figure S2).…”

Section: Resultsmentioning

confidence: 99%

“…43,45 The unsintered powder compact (ZnO-RT), composed of a mixture of ZnO and ZnAA powders, has an additional diffraction peak located at 26.6°(inset Figure 3a), a characteristic of the presence of unreacted Zn(acac) 2 •xH 2 O. 41,42 To understand the chemical decomposition of ZnAA during CS, post-mortem Fourier transformed infrared (FTIR) spectroscopy was performed on different samples (Figure 3b). The infrared (IR) bands of the sample ZnO-RT and their assignment are summarized in Table 2.…”

Section: ■ Introductionmentioning

confidence: 99%

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Assessment of the Role of Speciation during Cold Sintering of ZnO Using Chelates

et al. 2021

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Cold sintering (CS) is a chemically driven densification technique enabling a substantial decrease in the sintering temperature of oxides, by several hundreds of degrees Celsius. Although the densification process in CS is known to be mainly driven by pressure solution creep, additional fundamental aspects driving the interfacial chemistry reactions are still a subject of debate. Herein, we focus on the aspect of speciation in the densification process. The densification of zinc oxide (ZnO) by CS using zinc acetylacetonate hydrate (Zn(acac)2·xH2O), a versatile ligand often used as a precursor for ZnO synthesis in wet chemistry, is reported. The successful densification of ZnO using H2O and Zn(acac)2·xH2O confirms the importance of speciation in CS, as ZnO has a very low solubility in pure H2O. The evolution of the system at different stages of sintering and the role of the Zn(acac)2·xH2O species were evaluated.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Assessment of the Role of Speciation during Cold Sintering of ZnO Using Chelates

et al. 2021

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“…For the Zn complex, most of the absorption maxima were almost identical to those of Hopo in keeping with the very similar electrochemical properties ( Figure S7 in the Supplementary Materials ). In keeping with previous reports on [Zn(acac) 2 ] [ 96 , 97 ], we assumed that the absorbing species were the solvent-coordinated complexes [Zn(opo) 2 (solvent) x ] with x = 1 or 2.…”

Section: Resultsmentioning

confidence: 99%

“… a In the case of the Cu and Zn complexes we assume the species [M(opo) 2 (solvent) x ] to be the absorbing species as in the case for [M(acac) 2 (solvent) x ] (x = 1 or 2) [ 84 , 85 , 86 , 96 , 97 ]. …”

Section: Figures Scheme and Tablesmentioning

confidence: 99%

FeIII, CuII and ZnII Complexes of the Rigid 9-Oxido-phenalenone Ligand—Spectroscopy, Electrochemistry, and Cytotoxic Properties

Butsch

Haseloer

Schmitz

et al. 2021

IJMS

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The three complexes [Fe(opo)3], [Cu(opo)2], and [Zn(opo)2] containing the non-innocent anionic ligand opo− (opo− = 9-oxido-phenalenone, Hopo = 9-hydroxyphenalonone) were synthesised from the corresponding acetylacetonates. [Zn(opo)2] was characterised using 1H nuclear magnetic resonance (NMR) spectroscopy, the paramagnetic [Fe(opo)3] and [Cu(opo)2] by electron paramagnetic resonance (EPR) spectroscopy. While the EPR spectra of [Cu(opo)2] and [Cu(acac)2] in dimethylformamide (DMF) solution are very similar, a rather narrow spectrum was observed for [Fe(opo)3] in tetrahydrofuran (THF) solution in contrast to the very broad spectrum of [Fe(acac)3] in THF (Hacac = acetylacetone, 2,4-pentanedione; acac− = acetylacetonate). The narrow, completely isotropic signal of [Fe(opo)3] disagrees with a metal-centred S = 5/2 spin system that is observed in the solid state. We assume spin-delocalisation to the opo ligand in the sense of an opo− to FeIII electron transfer. All compounds show several electrochemical opo-centred reduction waves in the range of −1 to −3 V vs. the ferrocene/ferrocenium couple. However, for CuII and FeIII the very first one-electron reductions are metal-centred. Electronic absorption in the UV to vis range are due to π–π* transitions in the opo core, giving Hopo and [Zn(opo)2] a yellow to orange colour. The structured bands ranging from 400 to 500 for all compounds are assigned to the lowest energy π−π* transitions. They show markedly higher intensities and slight shifts for the CuII (brown) and FeIII (red) complexes and we assume admixing metal contributions (MLCT for CuII, LMCT for FeIII). For both complexes long-wavelength absorptions assignable to d–d transitions were detected. Detailed spectroelectrochemical experiments confirm both the electrochemical and the optical assignments. Hopo and the complexes [Cu(opo)2], [Zn(opo)2], and [Fe(opo)3] show antiproliferative activities against HT-29 (colon cancer) and MCF-7 (breast cancer) cell lines in the range of a few µM, comparable to cisplatin under the same conditions.

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“…The bands at 1452 and 1392 cm −1 can be assigned to the δ CO and ν CH 3 of acac. 30 The combustion of the acac ligands adsorbed on the NiAl-LDH NC induces two exothermic events on the TG curve occurring conjointly with the dehydroxylation of the metal hydroxide slabs and the removal of interlayer anions ( Figure 1D). Due to the departure of adsorbed acac, a higher value of total weight loss (48.5%) is obtained compared to the theoretical value of 37% expected for a Ni 2 Al(OH) 6 Cl•2H 2 O composition.…”

Section: Resultsmentioning

confidence: 99%

Electrochromic Thin Films Based on NiAl Layered Double Hydroxide Nanoclusters for Smart Windows and Low-Power Displays

Koilraj

Takemoto

Tokudome

et al. 2020

ACS Appl. Nano Mater.

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To develop electrochromic thin films for smart windows and low-power displays, homogeneous thin films were produced by spin coating colloidal NiAl layered double hydroxide (LDH) nanocluster solutions on a fluorine-doped tin oxide (FTO) glass substrate. The nano-LDH dispersion was synthesized via a facile one-step epoxide mediated process at room temperature. In situ relative transmittance measurements at 400 nm, recorded during potential scans in cyclic voltammetry or differential pulse chronoamperometry, showed the electrochromic behavior of the homogeneous thin films. The impact of various parameters on the electrochromic properties of the films was detailed, such as the thickness of the film, the nature of the electrolyte, and the presence of electroactive anions. The electrochromic properties, namely, the change in transmittance (ΔT) and the bleaching reversibility, were greatly improved using alkaline metal hydroxide as the electrolyte and in the presence of Fe(CN) 6 4−. The performances that we reached from the deposition of nanoclusters can be advantageously compared to the literature with ΔT = 70% and fast and good reversibility. Upon calcination, the NiAl-LDH film converted into mixed oxides (NiO and NiAl 2 O 4). The higher the calcination temperature, the lower was the ΔT value. The presence of porosity within the thin films, through the introduction of sacrificial polymeric beads and then decomposition at 400°C, was investigated, highlighting an enhancement of the ΔT value attributed to better accessibility to the nickel redox sites.

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Zinc acetylacetonate hydrate adducted with nitrogen donor ligands: Synthesis, spectroscopic characterization, and thermal analysis

Cited by 14 publications

References 41 publications

Assessment of the Role of Speciation during Cold Sintering of ZnO Using Chelates

Assessment of the Role of Speciation during Cold Sintering of ZnO Using Chelates

FeIII, CuII and ZnII Complexes of the Rigid 9-Oxido-phenalenone Ligand—Spectroscopy, Electrochemistry, and Cytotoxic Properties

Electrochromic Thin Films Based on NiAl Layered Double Hydroxide Nanoclusters for Smart Windows and Low-Power Displays

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