A Tetranuclear Mixed-Valence Manganese Complex of a Diimine Ligand Derived from 1,4-Diformyl-2,3-dihydroxybenzene: Synthesis, Structure, and Magnetic Properties

2009 ◽  
Vol 62 (9) ◽  
pp. 1119 ◽  
Author(s):  
Humphrey L. C. Feltham ◽  
Rodolphe Clérac ◽  
Sally Brooker
Keyword(s):  
Mixed Valence ◽  
Manganese Ions ◽  
One Pot ◽  
X Ray ◽  
Magnetic Analysis ◽  
Diimine Ligand ◽  
Jahn Teller ◽  
Planar Array ◽  
Ground Spin State

An acyclic hexadentate diimine ligand, H4L1, was prepared in situ in methanol by the condensation of 1,4-diformyl-2,3-dihydroxybenzene (1) with 2-aminoethanol, and complexed directly with two equivalents of MnII(OAc)2·4H2O or MnIII(OAc)3·2H2O, or with one equivalent of each. All three of these one-pot reactions gave the mixed-valent tetrametallic complex [MnII2MnIII2(L1)2(OAc)2(solvents)4], [2(solvents)4]. An X-ray crystal structure determination on [2(MeOH)4]·2MeOH revealed a centre of inversion in the middle of the complex. The four metal ions are in an almost planar array, sandwiched by two offset ligands which provide all of the equatorial donors, with the axial sites occupied by acetate ions and methanol molecules. The two manganese(II) ions are seven coordinate and centrally located, whereas the two manganese(III) ions are Jahn–Teller elongated octahedra and are located in the outer sites. Magnetic analysis of an air-dried sample, [2(MeOH)2(H2O)2]·3H2O, showed that weak antiferromagnetic interactions between the manganese ions dominate, resulting in a low ground spin state.

scholarly journals Pressure-induced Jahn-Teller Switch in the Homoleptic Hybrid Perovskite [(CH3)2NH2]Cu(HCOO)3: Orbital Reordering by Unconventional Degrees of Freedom

2021 ◽  
Author(s):  
Rebecca Scatena ◽  
Michał Andrzejewski ◽  
Roger D Johnson ◽  
Piero Macchi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Coordination Polymer ◽  
Degrees Of Freedom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite ◽  
Jahn Teller

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...

Zirconium complexes of a cyclopentadienyl-amido ligand with a pendant amine donor via amine and alkane elimination

1996 ◽  
Vol 74 (9) ◽  
pp. 1696-1703 ◽  
Author(s):  
Ying Mu ◽  
Warren E. Piers ◽  
Donald C. MacQuarrie ◽  
Michael J. Zaworotko
Keyword(s):  
Lewis Acids ◽  
Methyl Chloride ◽  
Monoclinic Space Group ◽  
One Pot ◽  
Amido Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Zirconium Complexes ◽  
Alkane Elimination

Zirconium complexes of the multidentate ligand CpHNMeSiN(H)R (SiNR = -SiMe2N-t-butyl; NMe = -CH2CH2NMe2, 1) were prepared and characterized via amine and alkane elimination procedures. Reaction of 1 with Zr(NMe2)4 gave a mixture of bis-amido complexes 2 in which the ligand was 1,2 and 1,3 substituted. This mixture was converted to the analogous dichlorides 3 using Me2NH•HCl and 1,3-3 was purified at this stage; alternatively, 1,3-3 was obtained in one pot from 1 and Zr(NMe2)4 in ≈70% yield. Conversion of 1,3-3 to dimethyl compound (CpNMeSiNR)Zr(CH3)2, 1,3-4, was accomplished via reaction of the dichloride with methyllithium; methide abstraction with the Lewis acids B(C6F5)3 and [Ph3C]+[B(C6F5)4]− generated the cationic alkyls [(CpNMeSiNR)Zr(CH3)]+[R′B(C6F5)3]− (R′ = CH3, 6a; C6F6, 6b), which were characterized by NMR spectroscopy. Zirconium complexes containing 1 ligated as its 1,2 isomer were obtained from alkane elimination reactions between 1 and in situ prepared RnZrCl4−n (R = CH3, n = 3; R = CH2SiMe3, n = 2). 1,2-3 and the methyl chloride complex 1,2-(CpNMeSiNR)Zr(CH3)Cl, 5, were obtained in 18 and 30% yield, respectively. Complex 5 was characterized by X-ray crystallography (monoclinic, space group P21/a, a = 9.6951(10) Å, b = 14.3794(16) Å, c = 14.364(3) Å, V = 1990.3(5) Å3, Z = 4, R = 0.046, Rw = 0.041.) Key words: amine elimination, Cp-amido, zirconium complexes.

scholarly journals Poly (N-Methyl Aniline)-Li Nanocomposite as an Electrolyte for Rechargeable Battery: In-situ Recipe

2020 ◽  
Vol 170 ◽  
pp. 01018
Author(s):  
Nishigandh Pande ◽  
Adinath Jambhale ◽  
Dipika Jaspal ◽  
Jalinder Ambekar ◽  
Himanshu Patil
Keyword(s):  
Cost Effective ◽  
Rechargeable Battery ◽  
Discharge Process ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
In Situ Method ◽  
Mechanism Of Interaction ◽  
Uv Visible

The synthesis of cost-effective and safe polymeric nanocomposite materials has been a subject of interest and study for material science researchers. Poly (N-Methyl Aniline) –Li nanocomposite has been synthesized by a one-pot in-situ method and has been explored as an electrolyte in the battery. Poly (N-Methyl Aniline)-Li nanocomposite prepared, has been characterized by UV-visible, FTIR, FE-SEM, X-ray diffraction techniques. A mechanism of interaction of lithiumion with nitrogen at the imine site has been proposed. The charge-discharge process of poly (N-Methyl Aniline) –Li nanocomposite, when used in the battery, has been discussed.

Probing Molten Salt Flux Reactions Using Time-Resolved in Situ High-Temperature Powder X-ray Diffraction:  A New Synthesis Route to the Mixed-Valence NaTi2O4

2004 ◽  
Vol 16 (6) ◽  
pp. 1153-1159 ◽  
Author(s):  
Margret J. Geselbracht ◽  
Liam D. Noailles ◽  
Lien T. Ngo ◽  
Jessica H. Pikul ◽  
Richard I. Walton ◽  
...  
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Mixed Valence ◽  
Salt Flux ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Synthesis Route ◽  
New Synthesis

Insight into growth of Au–Pt bimetallic nanoparticles: anin situXAS study

2017 ◽  
Vol 24 (4) ◽  
pp. 825-835 ◽  
Author(s):  
Chandrani Nayak ◽  
D. Bhattacharyya ◽  
K. Bhattacharyya ◽  
A. K. Tripathi ◽  
R. D. Bapat ◽  
...  
Keyword(s):  
Bimetallic Nanoparticles ◽  
Energy Dispersive ◽  
Core Shell ◽  
One Pot ◽  
X Ray ◽  
The Core ◽  
One Pot Synthesis ◽  
X Ray Absorption ◽  
Insight Into

Au–Pt bimetallic nanoparticles have been synthesized through a one-pot synthesis route from their respective chloride precursors using block copolymer as a stabilizer. Growth of the nanoparticles has been studied by simultaneousin situmeasurement of X-ray absorption spectroscopy (XAS) and UV–Vis spectroscopy at the energy-dispersive EXAFS beamline (BL-08) at Indus-2 SRS at RRCAT, Indore, India.In situXAS spectra, comprising both X-ray near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) parts, have been measured simultaneously at the Au and PtL3-edges. While the XANES spectra of the precursors provide real-time information on the reduction process, the EXAFS spectra reveal the structure of the clusters formed in the intermediate stages of growth. This insight into the formation process throws light on how the difference in the reduction potential of the two precursors could be used to obtain the core–shell-type configuration of a bimetallic alloy in a one-pot synthesis method. The core–shell-type structure of the nanoparticles has also been confirmed byex situenergy-dispersive spectroscopy line-scan and X-ray photoelectron spectroscopy measurements within situion etching on fully formed nanoparticles.

Synthesis, characterization, X-ray structure, and mixed-valence states of trans-dichlorotin(IV)-5,10,15,20-tetraferrocenylporphyrin

2011 ◽  
Vol 15 (07n08) ◽  
pp. 612-621 ◽  
Author(s):  
Pavlo V. Solntsev ◽  
Ben D. Neisen ◽  
Jared R. Sabin ◽  
Nikolay N. Gerasimchuk ◽  
Victor N. Nemykin
Keyword(s):  
Density Functional ◽  
Mixed Valence ◽  
Nir Spectroscopy ◽  
Density Functional Theory Calculations ◽  
Chemical Oxidation ◽  
Functional Theory ◽  
X Ray ◽  
Valence States ◽  
In Trans

Reaction between H2TFcP (TFcP2- is a dianion of 5,10,15,20-tetraferrocenylporphyrin) with tin(II) chloride results in formation of the trans- Cl2SnTFcP complex, which was characterized by UV-vis, MCD, 1H and 13C NMR, and APCI MS methods. X-ray single crystal analysis was used to determine the structure of the target compound. Crystallography reveals a very unusual α,α,β,β-conformation of the ferrocene groups and largely planar structure of the porphyrin macrocycle. Density functional theory calculations predict that the HOMO in trans- Cl2SnTFcP is predominantly ferrocene centered, while LUMO is primarily localized over the porphyrin core. Redox properties of the trans- Cl2SnTFcP complex were investigated using electrochemical (CV and DPV), spectroelectrochemical, and chemical oxidation approaches. Electrochemical experiments conducted in low-polarity solvent using non-coordinating electrolyte reveal the sequential oxidation of ferrocene substituents along with porphyrin-based single-electron oxidation and reduction processes. The first ferrocene oxidation process is separated by 130 mV from the next three ferrocene based oxidations, which are more closely spaced. Mixed-valence [trans- Cl2SnTFcP]+ was generated in situ by spectroelectrochemical and chemical oxidation approaches and characterized by UV-vis-NIR spectroscopy.

In situ Synchrotron X-ray Studies on Novel Mn Oxide Spinel Cathodes for Li-ion Batteries: Influence of Other Transition Elements

1998 ◽  
Vol 548 ◽  
Author(s):  
S. Mukerjee ◽  
X. Q. Yang ◽  
X. Sun ◽  
S. J. Lee ◽  
J. Mcbreen ◽  
...  
Keyword(s):  
Transition Element ◽  
Cycle Life ◽  
Partial Substitution ◽  
Exact Nature ◽  
Transition Elements ◽  
Potential Region ◽  
X Ray ◽  
Jahn Teller ◽  
Oxide Spinel

ABSTRACTPartial substitution of Mn in lithium manganese oxide spinel materials by Cu and Ni greatly affects the electrochemistry and the cycle life characteristics of the cathode. Substitution with either metal or a combination of both shortens the 4.2 V plateau associated with the conversion of Mn3+ to Mn4+. A higher voltage plateau associated with oxidation of the substituted transition element is also observed. These substituent also significantly alter the onset of Jahn Teller distortions in the 3 V plateau. Synchrotron based in situ x-ray absorption (XAS) is used to determine the exact nature of the oxidation state changes in order to explain the overall capacities at the different voltage plateaus. Synchrotron based in situ x-ray diffraction (XRD) studies on LiCu0.5Mn1.504 shows single phase behavior in the 4-5 V region and a good cycle life. Lower cycle life characteristics for LiNi0.5Mn1.504 and LiNi0.25Cu0.25Mn1.504 are accounted for on the basis of several phase coexistence in this potential region. In the 3 V plateau however, the LiCu0.5Mn1.504 shows onset of the Jahn Teller distortions, in contrast to the LiNi0.5Mn1.504 and LNi0.25Cu0.25WMn1.504.

scholarly journals Probing Molten Salt Flux Reactions Using Time-Resolved in situ High-Temperature Powder X-Ray Diffraction: A New Synthesis Route to the Mixed-Valence NaTi2O4.

ChemInform ◽  
2004 ◽  
Vol 35 (23) ◽  
Author(s):  
Margret J. Geselbracht ◽  
Liam D. Noailles ◽  
Lien T. Ngo ◽  
Jessica H. Pikul ◽  
Richard I. Walton ◽  
...  
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Mixed Valence ◽  
Salt Flux ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Synthesis Route ◽  
New Synthesis

scholarly journals A one-pot multistep cyclization yielding thiadiazoloimidazole derivatives

2014 ◽  
Vol 10 ◽  
pp. 2989-2996 ◽  
Author(s):  
Debabrata Samanta ◽  
Anup Rana ◽  
Jan W Bats ◽  
Michael Schmittel
Keyword(s):  
Single Crystal ◽  
Mechanism Of Formation ◽  
One Pot ◽  
X Ray ◽  
Dft Computations ◽  
Methanesulfonyl Chloride ◽  
Intramolecular Reaction ◽  
Synthetic Procedure

A versatile synthetic procedure is described to prepare the benzimidazole-fused 1,2,4-thiadiazoles 2a–c via a methanesulfonyl chloride initiated multistep cyclization involving the intramolecular reaction of an in-situ generated carbodiimide with a thiourea unit. The structure of the intricate heterocycle 2a was confirmed by single-crystal X-ray analysis and its mechanism of formation supported by DFT computations.

In Situ XAFS of the LixNi0.8Co0.2O2 Cathode for Lithium-Ion Batteries

1999 ◽  
Vol 590 ◽  
Author(s):  
A. J. Kropf ◽  
C. S. Johnson
Keyword(s):  
Lithium Ion ◽  
Edge Structure ◽  
X Ray ◽  
Metal Metal ◽  
Jahn Teller ◽  
A Cell ◽  
X Ray Absorption ◽  
Content Range ◽  
Li Content

ABSTRACTThe layered LiNi0.8AsCo0.2O2 system is being considered as a new cathode material for the lithium-ion battery. Compared with LiCoO2, the standard cathode formulation, it possesses improved electrochemical performance at a projected lower cost. In situ x-ray absorption fine-structure spectroscopy (XAFS) measurements were conducted on a cell cycled at a moderate rate and normal Li-ion operating voltages (3.0-4.1 V). The XAFS data collected at the Ni and Co edges approximately every 30 min. revealed details about the response of the cathode to Li insertion and extraction. These measurements on the LixNi0.8AsCo0.2O2 cathode (0.29<×<0.78) demonstrated the excellent reversibility of the cathode's short-range structure. However, the Co and Ni atoms behaved differently in response to Li insertion. This study corroborates previous work that explains the XAFS of the Ni atoms in terms of a Ni3+ Jahn-Teller ion. An analysis of the metal-metal distances suggests, contrary to a qualitative analysis of the x-ray absorption near-edge structure (XANES), that the Co3+ is oxidized to the maximum extent possible (within the Li content range of this experiment) at x = 0.47 ± 0.04, and further oxidation occurs at the Ni site.

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