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The structural and dynamical behaviors of the cryptophanes bearing molecules as well as their interaction with xenon are studied by using [.sup.1.H] and [.sup.128.Xe] NMR. The host molecules are shown to exist in aqueous solution under different conformations in very slow exchange whereas the cryptophanes in such conformation are unable to complex xenon.

The (super 1)H chemical shift variations are monitored under xenon pressures to determine the noble gas binding constant. The comparison to the exchange experienced by protein protons shows that the exchange between the open and closed conformations of wild-type bacteriophage T4 lysozome is not required for xenon binding.

The combination of different xenon-based NMR methods is used to investigate the hydrophobic cavity of lipid transfer protein from Nicotiana tabacum. The study of (super 129)Xe chemical shifts and relaxation times as a function of the noble gas or protein concentrations provides insight into the affinity of xenon to the protein.

The study of the interaction between xenon and two cryptophane derivatives in organic solution is carried out. The results clearly indicate that in the design of new cage molecules for biosensing, the separation of cryptophane diastereomers is important because their affinity and their properties vis-a-vis could be strongly different.

Longitudinal relaxation times T(sub 1) of laser-polarized xenon in water solutions containing alpha-cylodextrin and wheat nonspecific lipid transfer protein are measured. It reveals that even with an atom of high polarizability, such as xenon, the van der Waals energy is not sufficiently predominant to avoid large amplitude motions of an apolar guest around its average sites.

Research has been conducted on the mononuclear manganese(II) complex. The crystal structure and the electrochemical behavior of this complex in organic medium have been investigated and details are reported.

The structural characterization of stable complexes of pentavalent uranyl synthesized from the reaction of the complex with the bulky amine-phenolate ligand potassium salt [K.sub.2](salan-[super]t[Bu.sub.2]) or the Schiff base ligand potassium salt [K.sub.2](salophen-[super]t[Bu.sun.2]) in pyridine is described. The presence of a back-bonding interaction in the pentavalent uranyl complexes possibly contributed significantly to the observed solution stability of the [U[O.sub.2](salan-[super]t[Bu.sub.2])(py)K] and [U[O.sub.2](salophen-[super]t[Bu.sub.2])(py)K] complexes with respect to disproportionation and hydrolysis.

The mixed-valent diiron(II, III) complexes of unsymmetrical phenolato ligand exchange are studied by Mossbauer spectroscopy and electrochemical techniques. The drastic effects of aqua ligand exchange and deprotonation on the electronic structure and redox potentials of diiron centers are illustrated.

Research has been conducted on dimanganese(II) complexes with unsymmetrical phenol ligand. The authors report that these complexes can react with hydrogen peroxide in acetonitrile solution.

Research has been conducted on unsymmetrical phenol ligand. The authors report that the reactions of this ligand with Mn(OAc) (sub)2 .4H (sub)2 O carried out in the presence of NaOBz lead to dimanganese(II) complexes.

The dimanganese(ll,ll) complexes 1a [Mn[sub 2](L)(OAc)[sub 2](CH[sub 3]OH)](CIO[sub 4]) and lb [Mn2(L)(OBz)[sub 2](H[sub 2]O)](CIO[sub 4]), where HL is the unsymmetrical phenol ligand 2-(bis-(2-pyridylmethyl)aminomethyl)-6-((2-pyridylmethyl)(benzyl)aminomet hyl)4-methylphenol, react with hydrogen peroxide in acetonitrile solution. The disproportionation reaction was monitored by electrospray ionization mass spectrometry (ESI-MS) and EPR and UV-visible spectroscopies. Extensive EPR studies have shown that a species (2) exhibiting a 16-line spectrum at g ∼ 2 persists during catalysis. ESI-MS experiments conducted similarly during catalysis associate 2a with a peak at 729 (791 for 2b) corresponding to the formula [Mn[sup III]Mn[sup IV]V(L)(O)[sub 2](OAc)][sup +] ([Mn[sup III]Mn[sup IV](L)(O)[sub 2](OBz)][sup +] for 2b). At the end of the reaction, it is partly replaced by a species (3) possessing a broad unfeatured signal at g ∼ 2. ESI-MS associates 3a with a peak at 713 (775 for 3b) corresponding to the formula [Mn[sup II]Mn[sup III](L)(O)(OAc)][sup +] ([Mn[sup II]Mn[sup III](L)(O)(OBz)][sup +] for 3b). In the presence of H[sub 2, sup 18]O, these two peaks move to 733 and to 715 indicating the presence of two and one oxo ligands, respectively. When H[sub 2, sup 18]O[sub 2] is used, 2a and 3a are labeled showing that the oxo ligands come from H[sub 2]O[sub 2]. Interestingly, when an equimolar mixture of H[sub 2]O[sub 2] and H[sub 2, sup 18]O[sub 2] is used, only unlabeled and doubly labeled 2a/b are formed, showing that its two oxo ligands come from the same H[sub 2]O[sub 2] molecule. All these experiments lead to attribute the formula [Mn[sup III]Mn[sup IV](L)-(O)[sub 2](OAc)][sup +] to 2a and to 3a the formula [Mn[sup II]Mn[sup III](L)(O)(OAc)][sup +]. Freeze-quench/EPR experiments revealed that 2a appears at 500 ms and that another species with a 6-line spectrum is formed transiently at ca. 100 ms. 2a was prepared by reaction of la with reft-butyl hydroperoxide as shown by EPR and UV-visible spectroscopies and ESI-MS experiments, its structure was studied by X-ray absorption experiments which revealed the presence of two or three O atoms at 1.87 Å and three or two N/O atoms at 2.14 Å. In addition one N atom was found at a longer distance (2.3 Å) and one Mn at 2.63 Å. 2a can be one-electron oxidized at E[sub ½] = 0.91 V[sub NHE] (ΔE[sub ½] = 0.08 V) leading to its Mn[sup IV]Mn[sup IV] analogue. The formation of 2a from la was monitored by UV-visible and X-ray absorption spectroscopies. Both concur to show that an intermediate Mn[sup II]Mn[sup III] species, resembling 4a [Mn[sub 2](L)(OAc)[sub 2](H[sub 2]O)](ClO[sub 4])[sub 2], the one-electron-oxidized form of 1a, is formed initially and transforms into 2a. The structures of the active intermediates 2 and 3 are discussed in light of their: spectroscopic properties, and potential mechanisms are considered and discussed in the context of the biological reaction. [ABSTRACT FROM AUTHOR]

Reactions of the unsymmetrical phenol ligand 2-(bis(2-pyridyimethyl)aminomethyl)-6-((2-pyridylmethyl)(benzyl)aminometh yl)-4-methylphenol with Mn(OAc)[sub 2]·4H[sub 2]O or Mn(H[sub 2]O)[sub 6](ClO[sub 4])[sub 2] in the presence of NaOBz affords the dimanganese(II) complexes 1(CH[sub 3]OH), [Mn[sub 2](L)(OAc)[sub 2](CH[sub 3]OH)](ClO[sub 4]), and 2(H[sub 2]O), [Mn[sub 2](L)(OBz)[sub 2](H[sub 2]O)](ClO[sub 4]), respectively. On the other hand, reaction of the ligand with hydrated manganese(III) acetate furnishes the mixedvalent derivative 3(H[sub 2]O), [Mn[sub 2](L)(OAc)[sub 2](H[sub 2]O)](ClO[sub 4])[sub 2]. The three complexes have been characterized by X-ray crystallography. 1(CH[sub 3]OH) crystallizes in the monoclinic system, space group P2[sub 1]/c, with a = 10.9215(6) Å, b = 20.2318(12) Å, c = 19.1354(12) Å, α = 90°, β = 97.5310(10)°, γ = 90°, V = 4191.7 A³, and Z = 4. 2(H[sub 2]O) crystallizes in the monoclinic system, space group P2[sub 1]/n, with a = 10.9215(6) Å, b = 20.2318(12) Å, c = 19.1354(12) Å, α = 90°, β = 97.5310(10)°, γ = 90°, V = 4191.7 ų, and Z = 4.3(H[sub 2]O) crystallizes in the monoclinic system, space group P2[sub 1]/c, with a = 11.144(6) Å, b = 18.737(10) Å, c = 23.949(13) Å, α = 90°, β = 95.910(10)°, γ = 90°, V-4974(5) ų, and Z = 4. Magnetic measurements revealed that the three compounds exhibit very similar magnetic exchange interactions -J = 4.3(3) cm[sup -1]. They were used to establish tentative magnetostructural correlations which show that for the dimanganese(II) complexes -J decreases when the Mn-O[sub phenoxo] distance increases as expected from orbital overlap considerations. For the dimanganese(II,III) complexes, crystallographic results show that the Mn[sup II]-O[sub phenoxo] and Mn[sup III]-O[sub phenoxo] bond lengths are inversely correlated. An... [ABSTRACT FROM AUTHOR]

Examines the properties of the dinuclear manganese complex. Outcome on the reaction of manganese compounds with ethylamines compounds; X-ray crystallography of the binuclear manganese compounds; Electrochemical behavior of the manganese complex.

Organic materials derived from biomass can constitute a viable option as replacements for inorganic materials in lithium-ion battery electrodes owing to their low production costs, recyclability, and structural diversity. Among them, conjugated carbonyls have become the most promising type of organic electrode material as they present high theoretical capacity, fast reaction kinetics, and quasi-infinite structural diversity. In this letter, we report a new perylene-based all-organic redox battery comprising two aromatic conjugated carbonyl electrode materials, the prelithiated tetra-lithium perylene-3,4,9,10-tetracarboxylate (PTCLi6) as negative electrode material and the poly(N-n-hexyl-3,4,9,10-perylene tetracarboxylic)imide (PTCI) as positive electrode material. The resulting battery shows promising long-term cycling stability up to 200 cycles. In view of the enhanced cycling performances, the two organic materials studied herein are proposed as suitable candidates for the development of new all-organic lithium-ion batteries.

This article describes the study of a linear trimer and three polyarylamines PB1-3 containing a 3,4'-biphenyl ferromagnetic coupler. The synthesis of the model compound (trimer) and the polymers has been presented. The formation of radical cations was studied using electrochemical and optical (UV-vis) methods. The chemical oxidation of these compounds leads to the creation of high-spin states, evidenced by pulsed EPR nutation spectroscopy. A quartet spin state is observed for the trimer model compound, and its J exchange coupling constant has been measured experimentally (J/k = 11.8 K) and compared quantitatively to DFT calculations. Most importantly, quartet and quintet spin states have been formed for PB3 and PB2, respectively. These last two doped polymers thus exhibit the highest spin states observed to date for linear polyarylamine compounds.

This report describes the study of a dimer d 2+ and a linear trimer t 3+ of amminium radical cations coupled by 3,4'-biphenyl spin coupling units. The synthesis of the parent diamine and triamine and their optical and electrochemical properties obtained by UV-visible and cyclic voltammetry are presented. The chemical doping of the parent diamine d and triamine t was performed quantitatively to obtain samples containing the corresponding dimer d 2+ and trimer t 3+ in almost pure high-spin states as evidenced by pulsed EPR nutation spectroscopy. The J coupling constants of the corresponding S = 1 and S = 3/2 spin states were measured (J/k = 135 K) and compared quantitatively to DFT calculations.

Polyarylamine containing meta-para-para-aniline units in the main chain and meta-para-aniline units in the pendant chains was synthesized. The polymer can be oxidized to radical cations in chemical or electrochemical ways. The presence of meta-phenylenes in the polymer chemical structure allows for the ferromagnetic coupling of electronic spins, which leads to the formation of high spin states. Detailed pulsed-EPR study indicates that the S = 2 spin state was reached for the best oxidation level. Quantitative magnetization measurements reveal that the doped polymer contains mainly S = 2 spin states and a fraction of S = 3/2 spin states. The efficiency of the oxidation was determined to be 74%. To the best of our knowledge, this polymer is the first example of a linear doped polyarylamine combining such high spin states with high doping efficiency.