Aromatic Dicarboxylate Research Articles

Heterogeneous intercalated metal-organic framework active materials for fast-charging non-aqueous Li-ion capacitors

Intercalated metal-organic frameworks (iMOFs) based on aromatic dicarboxylate are appealing negative electrode active materials for Li-based electrochemical energy storage devices. They store Li ions at approximately 0.8 V vs. Li/Li+ and, thus, avoid Li metal plating during cell operation. However, their fast-charging capability is limited. Here, to circumvent this issue, we propose iMOFs with multi-aromatic units selected using machine learning and synthesized via solution spray drying. A naphthalene-based multivariate material with nanometric thickness allows the reversible storage of Li-ions in non-aqueous Li metal cell configuration reaching 85% capacity retention at 400 mA g−1 (i.e., 30 min for full charge) and 20 °C compared to cycling at 20 mA g−1 (i.e., 10 h for full charge). The same material, tested in combination with an activated carbon-based positive electrode, enables a discharge capacity retention of about 91% after 1000 cycles at 0.15 mA cm−2 (i.e., 2 h for full charge) and 20 °C. We elucidate the charge storage mechanism and demonstrate that during Li intercalation, the distorted crystal structure promotes electron delocalization by controlling the frame vibration. As a result, a phase transition suppresses phase separation, thus, benefitting the electrode’s fast charging behavior.

Copper(II) and zinc(II) complexes bridged by benzenoid aromatic oxocarbon and dicarboxylate dianions

A novel series of Cu(II) and Zn(II) complexes were constructed through the bridging croconate (C5O5)2−, squarate (C4O4)2− and 2,5-pyridine-dicarboxylate (Py2,5-dc)2− dianions. These include pent- [Cu5(epdmpy)4(C5O5)2(H2O)6](ClO4)6‧12H2O (1) and tri-nuclear [Cu3(bepza)2(Py2,5-dc)2(ClO4)2(H2O)2]‧2H2O (4), dinuclear [Zn2(MeDPA)2(C4O4)(H2O)4](ClO4)2 (7), and 1-D- coordination polymers (CPs) catena-{[Cu2(bpzpy)2(C5O5)](ClO4)2‧MeOH} (2) and catena-{[Zn(4,4′-bipy)(H2O)4](C5O5)(H2O)} (6) as well as the mononuclear [Cu(HBph2,2′-dc)(pmdien)]ClO4 (5) have been synthesized and spectroscopically characterized as well as by single crystal X-ray crystallography. The reaction of aqueous solution Cu(ClO4)2, pymeea and C5O52− resulted in the unprecedently bis(oxalato) [Cu2(Pymeea)2(C2O4)(ClO4)2(H2O)2] (3). In these complexes, (C5O5)2−, squarate (C4O4)2− and (Py2,5-dc)2− ligands display a variety of coordination bonding modes. In complexes 1 and 2 the croconato is binding as 1,2-bidentate-3-monodentate but in addition 5-mono-dentate semi-coordinate bonding was detected for 2, whereas in 6 as counter dianion. The bonding mode in the squarato 7 was achieved through the trans μ1,3-mono-dentate. In the di-carboxylato compounds, only five-membered chelate ring was formed in 5via one of the carboxylate groups, whereas in 4 bridging was conducted through a mono-carboxylate and five-membered chelate ring including the second carboxylate and pyridyl nitrogen. In complexes 1–5 and 7, hydrogen bonds of type OH⋯O and/or NH⋯O are connecting the complex cations with the perchlorate anions/ligands to generate different dimensional supramolecular network structures, whereas in 6, the 3D network was formed through hydrogen bonding between the coordinated aqua and lattice water molecules. Non-covalent ring⋯ring interactions were also observed between pyridyl rings in complexes 1, 6 and 7, and between pyrazolyl rings as well as pyridyl ring in 2.

Efficient ruthenium-catalyzed hydrogenation of aromatic dicarboxylates supported by a 1-phenylethylamine-based P,N,N-ligand

The ruthenium-catalyzed hydrogenation of aromatic dicarboxylates supported by a 1-phenylethylamine-derived P,N,N-pincer ligand has been developed. The newly developed catalytic system displayed high efficiency to the hydrogenation of aromatic dicarboxylates with broad substrate scope and high functional group tolerance. The hydrogenation led to the formation of a variety of 1,2-, 1,3- and 1,4-benzenedimethanols as well as heteroaromatic dimethanols in good to high yields. The synthetic utility of the hydrogenation is highlighted by a gram-scale preparation of 1,4-benzenedimethanol at a low catalyst loading and the synthesis of pyrethroid hygienic insecticide heptafluthrin.

Supramolecular chemistry of two new bis(1,2,3-triazolyl)pyridine macrocycles: metal complexation, self-assembly and anion binding.

Two new macrocycles containing the bis(1,2,3-triazolyl)pyridine (btp) motif were prepared in high yields from a btp diazide precursor (1). Solution 1H NMR studies show that this diazide undergoes self-assembly with divalent transition metal ions to form ML2 complexes with pendant azide groups, apparently suitable for conversion into metal-templated catenanes; however attempts to form these catenanes were unsuccessful. Instead a new macrocycle containing two btp motifs was prepared, which forms a nanotube structure in the solid state. Reduction of the azide groups to amines followed by amide bond formation was used to convert 1 into macrocycle 8 containing btp and isophthalamide functionalities. This macrocycle binds halide and oxalate anions in acetonitrile solely through the isophthalamide motif, and binds aromatic dicarboxylates very strongly through both the isophthalamide amide donors and the btp triazole donors. The macrocycle was complexed with Pd(II) and the resulting complexes were shown to bind strongly to halide anions. The solid state structures of [Pd·8·X]BF4 (X = Cl-, Br-, I-) were investigated by X-ray crystallography, which showed that [Pd·8·Br] forms an unusual "chain of dimers" structure assembled by metal complexation, N-H⋯Br- hydrogen bonding and short Pd⋯Pd contacts.

Reduction of Aromatic Dimethyl Ene-Dicarboxylates to Dimethyl Succinates with Titanium Ylides

Background: Generally, it was assumed that Tebbe- and Takai-reagents are useful for methenylation reactions. Objective: Applying these reagents to aromatic ene dicarboxylates, unexpectedly the reduction of double bonds was achieved. There is, however, a different behaviour of both reagents. Takai-reagent yields reduction while Tebbe-reagent prefers isomerisation. Methods: A selective and unique method has been shown to reduce a double bond of ene-dicarboxylates while both carboxylic groups are not affected at all. In addition, this method is easy and very cheap using Takai-reagent. Results: If isomerisation is to be carried out, without any reduction of a double bond, Tebbe-reagent can be applied. To our knowledge, such reactions have not been published yet. Conclusion: We have shown a selective methodology to reduce aromatic ene-dicarboxylates with titanium ylides.

Structural basis of terephthalate recognition by solute binding protein TphC

Biological degradation of Polyethylene terephthalate (PET) plastic and assimilation of the corresponding monomers ethylene glycol and terephthalate (TPA) into central metabolism offers an attractive route for bio-based molecular recycling and bioremediation applications. A key step is the cellular uptake of the non-permeable TPA into bacterial cells which has been shown to be dependent upon the presence of the key tphC gene. However, little is known from a biochemical and structural perspective about the encoded solute binding protein, TphC. Here, we report the biochemical and structural characterisation of TphC in both open and TPA-bound closed conformations. This analysis demonstrates the narrow ligand specificity of TphC towards aromatic para-substituted dicarboxylates, such as TPA and closely related analogues. Further phylogenetic and genomic context analysis of the tph genes reveals homologous operons as a genetic resource for future biotechnological and metabolic engineering efforts towards circular plastic bio-economy solutions.

Fluorescent Supramolecular Organic Frameworks Constructed by Amidinium-Carboxylate Salt Bridges.

We report here a set of fluorescent supramolecular organic frameworks (SOFs) that incorporate aggregation-induced emission (AIE) units within their frameworks. The fluorescent SOFs of this study were constructed by linking the tetraphenylethylene (TPE)-based tetra(amidinium) cation TPE4+ and aromatic dicarboxylate anions through amidinium-carboxylate salt bridges. The resulting self-assembled structures are characterized by fluorescence quantum yields in the range of 4.6∼14 %. This emissive behavior is ascribed to a combination of electrostatic interactions and hydrogen bonds that operate in concert to impede motions that would otherwise lead to excited state energy dissipation. Single-crystal X-ray diffraction analyses revealed that the length of the dicarboxylate anion bridges has a considerable impact on the structural features of the resulting frameworks. Nevertheless, all SOFs prepared in the context of the present study were found to display emissive features characteristic of TPE-based AIE luminogens with only a modest dependence on the structural specifics being seen. The SOFs reported here could be reversibly "broken up" and "reformed" in response to acid/base stimuli. This reversible structural behavior is consistent with their SOF nature.

Pb2+-Containing Metal-Organic Rotaxane Frameworks (MORFs).

The metal-organic rotaxane framework (MORF) structures with the advantage of mechanically interlocking molecules (MIMs) have attracted intense interest from the chemical community. In this study, a set of MORFs (i.e., MORF-Pb-1 and MORF-Pb-2) are constructed using Pb2+, a tetraimidazolium macrocycle (Texas-sized molecular box; 14+), and aromatic dicarboxylate (p-phthalate dianions (PTADAs; 2) or 2,6-naphthalene dicarboxylate dianions (3)) via a one-pot three-layer diffusion protocol. In particular, an unusual Pb…Pb weak interaction was shown in MORF-Pb-1 (charactered with distance of 3.656 Å).

Stepwise Introduction of Flexibility into Aromatic Dicarboxylates Forming Uranyl Ion Coordination Polymers: a Comparison of 2‐Carboxyphenylacetate and 1,2‐Phenylenediacetate

Abstract2‐Carboxyphenylacetate (cpa2−) and 1,2‐phenylenediacetate (1,2‐pda2−) have been reacted with uranyl cations under solvo‐hydrothermal conditions to generate six homo‐ or heterometallic complexes. Both [UO2(cpa)] (1) and [UO2(cpa)(phen)] (2), where phen is 1,10‐phenanthroline, crystallize as monoperiodic coordination polymers. [Ni(bipy)3][(UO2)2(cpa)3]⋅2.5H2O (3), is a diperiodic network with the hcb topology, in which the hexagonal cells distort to accommodate the counterions. [UO2(cpa)2Ni(R,S‐Me6cyclam)] (4) crystallizes as a heterometallic diperiodic network in which uranyl dicarboxylate chains are assembled by bridging NiII cations. While [dmaepH2][(UO2)2(1,2‐pda)3]⋅3H2O (5), where dmaep is 1,4‐bis(2′‐dimethylaminoethyl)piperazine, is a diperiodic hcb network, [QH]2[(UO2)2(1,2‐pda)3]⋅3CH3CN (6), where Q is quinuclidine, is the first example of a triperiodic framework in the uranyl–phenylenediacetate family, its topological type being bto. The complex involving the related ligand 1,4‐phenylenediacetate (1,4‐pda2–), [QH]2[(UO2)2(1,4‐pda)3]⋅2CH3CN (7), is a daisy‐chain‐like monoperiodic polymer. These and previously reported results are discussed in terms of ligand flexibility and ability to form large chelate rings.

Low-Resistance Mechanism of Nanoflake Crystalline Aromatic Dicarboxylates with Selective Defects for Safe and Fast Charging Negative Electrodes

Low resistance of Li-intercalated negative electrodes is important for the safe and fast charging required for large-scale batteries. Here, we demonstrated that nanosized two-dimensional crystalline aromatic dicarboxylate negative electrode materials synthesized via spray drying exhibit low internal resistances at approximately 0.7 V vs Li/Li+, while retaining flat potential profiles. The spray-dried sample with a hollow structure is crushed into nanoflakes during ink preparation for electrode coating and forms a uniform and highly dispersed electrode structure. The charge-discharge evaluation indicates that the nanoflake sample showed smaller charge-discharge polarization than the bulk sample with stable cycling characteristics, resulting in significant high-rate property enhancement. Charge-transfer resistance of the nanoflake sample exhibits the lowest value (ca. 2.2 Ω cm2) among those reported for existing intercalation electrodes (5.2 to 235 Ω cm2). In comparison of the negative electrodes, the estimated maximum current density without Li deposition (ca. 316 mA cm-2) is more than 1 order of magnitude higher than that for currently used graphite (ca. 11 mA cm-2) and is also higher than those for high-rate oxides (137-298 mA cm-2). The resistance-crystal correlation using multiple regression analysis predictions and its verification reveal that this low resistance is owing to an improved Li acceptability associated with selective structural defects induced by the loss of incorporated crystallized water during drying. The crystal plane exposed by the selective structural defects is perpendicular to electronic and ionic conduction directions inside the solid, resulting in improved kinetics. Therefore, the proposed negative electrode allows safe and fast charging, with easy scale-up and sustainable resources.

2D MOFs with Ni(II), Cu(II), and Co(II) as Efficient Oxygen Evolution Electrocatalysts: Rationalization of Catalytic Performance vs Structure of the MOFs and Potential of the Redox Couples.

Earth-abundant transition-metal-based metal-organic frameworks (MOFs) are of immense interest for the development of efficient and durable heterogeneous water splitting electrocatalysts. This repot explores the design of two-dimensional (2D) MOFs with redox-active metal centers (Ni(II), Co(II), and Cu(II)) containing two types of electron-rich linkers such as bis(5-azabenzimidazole), linear L1 and angular L2, and aromatic dicarboxylates. The electron-rich linkers are considered to stabilize the higher oxidation state of the redox-active metal centers in the course of the electrocatalytic oxygen evolution reaction (OER) process. The 2D MOFs of L1 and L2 with Co(II) (1 and 3) and Ni(II) (2 and 4) have been produced via the conventional hydrothermal synthesis, while the MOFs of Cu(II) (Cu@1 and Cu@3) are obtained by the postsynthetic transmetallation reaction of MOFs 1 and 3. The electrocatalytic OER activities of the six MOFs have been studied to explore the influence of the redox potential of the transition-metal quasi-reversible couples and the coordination environment around the redox-active metal centers in the electrocatalytic activity. The lowest overpotential of 370 mV exhibited by MOF 2 with the highest current density and TOF value indicates the importance of the presence of coordinated water molecules and the lowest redox potential value of the most favorable quasi-reversible couple Ni+2/Ni+3. These catalysts exhibit a remarkable stability up to 1000 OER cycles. These studies pave the way for the design of MOF materials toward the development of a promising heterogeneous OER electrocatalyst.

Construction of highly water-stable fluorinated 2D coordination polymers with various N, N’-donors: Syntheses, crystal structures and photoluminescence properties

Four new 2D coordination polymers (CPs) of Cd(II), [Cd(tfbdc)(bpy)(H2O)2]n (1) [Cd(tfbdc)(bpe)(H2O)2]n (2), [Cd(tfbdc)(4bpdb)(H2O)2]n (3), and [Cd(tfbdc)(3bpdb)(H2O)2]n (4) (where, tfbdc ​= ​2,3,5,6-tetrafluoro-1,4-benzenedicarboxylate, bpy ​= ​4,4’-bipyridine, bpe ​= ​1,2-bis(4-pyridyl)ethylene, 4bpdb ​= ​1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene), and 3bpdb ​= ​1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene) were successfully synthesized by room temperature self-assembly of Cd(II), tfbdc2− and the N, N’-bipyridine linkers. All four CPs were thoroughly characterized by single-crystal X-ray diffraction and other physicochemical studies. Structural analysis revealed that CPs 1–4 feature a 2D network structure which is further extended to 3D supramolecular framework via intermolecular (O–H⋯O) hydrogen bonding interactions between the hydrogens of the coordinated water molecule and the free carboxylate oxygen of tfbdc2− dianion. Further, the use of various ancillary bipyridine linkers has resulted in the 2D networks 1–4 with different pore sizes. Interestingly, 1–4 exhibit water stability owing to the presence of fluorinated aromatic dicarboxylate ligand and also, photoluminescence emission attributed to intra-ligand and/or ligand-to-ligand charge transfer transitions.

Three luminescent Cd(II) coordination polymers containing aromatic dicarboxylate and flexible bis(benzimidazole) ligands as highly sensitive and selective sensors for detection of Cr2O72– oxoanions in water

Three Cd(II) coordination polymers (CPs), {[Cd(TCPA)(L)]·H2O}n (1), {[Cd(1,2-BDC)(L)]·H2O}n (2) and [Cd2(1,3-BDC)2(L)(H2O)2]n (3) (H2TCPA = 2,3,5,6-tetrachloroterephthalic acid, 1,2-H2BDC = 1,2-benzenedicarboxylic acid and 1,3-H2BDC = 1,3-benzenedicarboxylic acid, L = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)propane) were hydrothermally synthesized and characterized. 1 features a 2D {44} structure, which constructs a 3D supramolecular structure through π-π stacking interactions. 2 shows a 1D ladder-like chain which is additional extended into a 3D supramolecular network via π-π stacking interactions. 3 retains a 2D (3,4)-connected 3,4L83 net which can be broadened into a 3D supramolecular framework by OH···O hydrogen bonds. Both 1, 2 and 3 could serve as efficient probes for detecting of Cr2O72– anions with high quenching efficiency (Ksv) values (7820 M−1, 9460 M−1 and 20018 M−1 for 1, 2 and 3, separately) and low detection limit (0.42 μM, 0.37 μM and 0.15 μM for 1, 2 and 3, respectively).

Aromatic dicarboxylate incorporated new di- and tetranuclear cobalt(II) complexes: Synthetic and structural aspects, and evaluation of properties and catalytic activity

The synthetic and structural aspects as well as evaluation of magnetic properties and catalytic activity toward aerial oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylbenzoquinone of three new, two di- and one tetranuclear cobalt(II) complexes, [Co2(cpdp)(Hphth)]∙5H2O (1), [Co2(cpdp)(Hisophth)] (2) and [Co4(cpdp)2(terephth)]∙4.5CH3OH·5.5H2O (3), based on a symmetrical multidentate ligand, N,N'-Bis[2-carboxybenzomethyl]-N,N'-Bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol (H3cpdp) in combination with exogeneous aromatic dicarboxylic acids, such as phthalic acid (H2phth), isophthalic acid (H2isophth) and terephthalic acid (H2terephth) are reported. All three coordination complexes are characterized by microanalysis, solution electrical conductivity, FTIR, UV–Vis, mass spectrometry and cyclic voltammetry, including single crystal X-ray diffraction studies of 1 and 3. Structural studies reveal that complexes 1, 2 and 3 are comprised of [CoII2(µ-Hphth)], [CoII2(µ-Hisophth)] and [CoII4(µ4-terephth)] cores, respectively, linked by symmetrical ligand, cpdp3−. In the present complexes, the cobalt(II) ions are penta-coordinated exhibiting trigonal bipyramidal/square pyramidal geometry that is substantially distorted. In fact, tetranuclear complex 3 can be viewed as a “dimer-of-dimers” formed by self-assembly of two [CoII2(cpdp)]+ units absolutely bridged by one μ4:η1:η1:η1:η1 terephthalate group. Magnetic susceptibility studies show that the cobalt(II) ions in 1 and 3 are coupled antiferromagnetically, with J values of −13.7(1) and −13.4(2) cm−1, respectively. The catalytic activity of all three complexes has been investigated toward aerial oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylbenzoquinone. Kinetic data analysis following Michaelis-Menten treatment discloses that the catecholase-like activity of the complexes is influenced by the flexibility of the ligand cpdp3− that maintains the favourable metal-metal cooperativity and also by the geometry around the metal centers. To the best of our knowledge, to date very few di- and tetranuclear cobalt(II) complexes have been found in the literature to manifest the catecholase-like activity.

The effects of the coordination orientation and steric hindrance of ligands on the structural diversity of Pb(II) coordination polymers

Five new lead(II) coordination polymers, [Pb(L)]n (1), [Pb3(L)3]n·4nH2O (2), [Pb2(L)(1,2-bdc)]n·nH2O (3), [Pb2(L)(1,3-bdc)]n·nH2O (4) and [Pb4(L)2(1,4-bdc)2(H2O)2]n·2nH2O (5) (H2L = 4′-(4-carboxyphenyl)-6′-carboxycalte-2,2′-bipyridine, H2(1,2-bdc) = benzene-1,2-dicarboxylic acid, H2(1,3-bdc) = benzene-1,3-dicarboxylic acid and H2(1,4-bdc) = benzene-1,4-dicarboxylic acid) were prepared under hydrothermal conditions. Compound 1 shows a 2D ladder single-layer with the hcb topology. Compound 2 presents a 2D ladder double-layer, which shows a 3-connected hcb topology. Compound 3 exhibits a 1D loop chain based on [Pb4(COO)6] tetranuclear units. Compound 4 displays a (3,4)-connected 3D framework with 3,4T10 topology consisting of [Pb2O2] units. Compound 5 exhibits a self-penetrating 3D network based on [Pb4(COO)2] units, which features an intriguing new topological net. The structural diversity of 1–5 gives some insights that the pH value and coordination orientations of aromatic dicarboxylates play significant roles in construction of coordination polymers. Meanwhile, the hemi-directed or holo-directed coordination geometries depend on coordination numbers of Pb(II) ions. Furthermore, tetrel bonds enhance the structural stability of these Pb(II) coordination polymers.

Towards Building Blocks for Supramolecular Architectures Based on Azacryptates.

In this work, we report the synthesis of a new bis(tris(2-aminoethyl)amine) azacryptand L with triphenyl spacers. The binding properties of its dicopper complex for aromatic dicarboxylate anions (as TBA salts) were investigated, with the aim to obtain potential building blocks for supramolecular structures like rotaxanes and pseudo-rotaxanes. As expected, UV-Vis and emission studies of [Cu2L]4+ in water/acetonitrile mixture (pH = 7) showed a high affinity for biphenyl-4,4′-dicarboxylate (dfc2−), with a binding constant of 5.46 log units, due to the best match of the anion bite with the Cu(II)-Cu(II) distance in the cage’s cavity. Compared to other similar bistren cages, the difference of the affinity of [Cu2L]4+ for the tested anions was not so pronounced: conformational changes of L seem to promote a good interaction with both long (e.g., dfc2−) and short anions (e.g., terephthalate). The good affinity of [Cu2L]4+ for these dicarboxylates, together with hydrophobic interactions within the cage’s cavity, may promote the self-assembly of a stable 1:1 complex in water mixture. These results represent a good starting point for the application of these molecular systems as building units for the design of new supramolecular architectures based on non-covalent interactions, which could be of interest in all fields related to supramolecular devices.

Phase Transition Mechanism for Crystalline Aromatic Dicarboxylate in Li+ Intercalation

Crystalline aromatic dicarboxylate, also known as intercalated metal–organic frameworks, electrodes can be used in sustainable lithium-ion batteries owing to their low resource risks and eco-friend...

Structures and luminescent properties of two Tb(III) coordination polymers with aromatic dicarboxylates

Two Tb(III) coordination polymers with ligands of two kinds of dicarboxylates were synthesized under hydrothermal conditions. The molecular formulas of the complexes were as follows: {[Tb2(3,5-pdc)(3,4-pdc)2(H2O)4]·2H2O}n (1) and [Tb(1,4-bdc)0.5(3,4-pdc)(H2O)2]n (2) (3,5-H2pdc = 3,5-pyridinedicarboxylic acid; 3,4-H2pdc = 3,4-pyridinedicarboxylic acid; 1,4-H2bdc = 1,4-benzenedicarboxylic acid). The two complexes were characterized by elemental analyses and IR spectra. And the structures of the two complexes were tested by X-ray single crystal diffraction. The crystal structures show 3,4-pdc coordinated with Tb(III) by oxygen atoms on the carboxyl groups. They connected the lanthanide ions to form 1D chain or 2D layer. 3,5-Pdc and 1,4-bdc ligands were both connectors in the complexes. They connected the 1D chain or 2D layer to further form 2D layer or 3D framework. The complexes emitted the green characteristic fluorescence of Tb(III) with the excitations of UV-rays. The absolute quantum yields (Фabs) of luminescence for the two Tb(III) complexes were also tested and the values of Фabs (1) and Фabs (2) were 42% (λex = 297 nm) and 53% (λex = 295 nm), respectively. The testing results of fluorescence lifetime showed the 5D4 excited states for the two complexes all had long lifetime and they were 0.819 and 0.901 ms, respectively.

Functionalized Aromatic Dicarboxylate Ligands in Uranyl-Organic Assemblies: The Cases of Carboxycinnamate and 1,2-/1,3-Phenylenedioxydiacetate.

2-Carboxycinnamic acid (ccnH2) and the isomeric 1,2- and 1,3-phenylenedioxydiacetic acids (1,2- and 1,3-pddaH2) have been used to synthesize eight uranyl ion complexes under solvo-hydrothermal conditions. In the four complexes [PPh4]2[UO2(ccn)(NO3)]2 (1), [PPh4]2[UO2(ccn)(dibf)]2 (2), [UO2(ccn)(bipy)]2 (3), and [Ni(R,S-Me6cyclam)][UO2(ccn)(HCOO)]2 (4), the ccn2- dianion retains a nearly planar geometry, which favors the formation of the centrosymmetric [UO2(ccn)]2 dimeric unit. Additional terminal ligands, either neutral (bipy = 2,2'-bipyridine) or anionic (nitrate, dibf- = 1,3-dihydro-3-oxo-1-isobenzofuranacetate, and formate, the two latter formed in situ), complete the uranyl coordination sphere, leading in all cases to discrete, dinuclear species. Sodium(I) bonding to the carboxylate/ether O4 site of the 1,2-pdda2- dianion in the two complexes [UO2Na(1,2-pdda)(OH)] (5) and [(UO2)2Na2(1,2-pdda)2(C2O4)] (6) results in this ligand being planar. Further lateral coordination to uranyl and sodium bonding to a uranyl oxo group allow formation of heterometallic diperiodic networks containing monoperiodic uranyl-only subunits. In the absence of Na+ cations, 1,2-pdda2- adopts a conformation in which one carboxylate group is tilted out of the ligand plane in [UO2(1,2-pdda)2Ni(cyclam)] (7) and diaxial carboxylato bonding to nickel(II) unites uranyl-only monoperiodic subunits into a diperiodic network. The 1,3-pdda2- ligand in [UO2(1,3-pdda)(H2O)] (8) is also nonplanar with one tilted carboxylate group, and the bridging bidentate nature of both carboxylate groups allows formation of a triperiodic framework in which both metal and ligand are four-coordinated nodes. While the emission spectra of complexes 1 and 5 display the vibronic progression considered typical of uranyl ion, those of complexes 2, 4, and 8 show broad emission bands which in the case of complex 4 completely replace the uranyl emission and which appear to be ligand-centered. The low energy of these broad bands can be rationalized in terms of the close association of certain ligand pairs within the structures.

Tribute to Michel Armand: from Rocking Chair – Li-ion to Solid-State Lithium Batteries

Professor Michel Armand is one of the world's leading scientists in the R&D of modern energy storage systems. His scientific works have been devoted to the concepts and technologies of today's batteries, in particular, mastering research on electrodes and electrolytes. With respect to innovative discoveries, Michel had several scientific breakthroughs from the description of the solid-solution electrode and rocking-chair battery to the applications of novel materials utilized in all-solid-state batteries (SSBs); these refer to Li-ion, Na-ion, Li-S, and Li-air cells. At a young age, he formalized the concept of electrochemical intercalation and fabricated the first SSB with sodium-intercalated graphite as the electrode in 1972. Subsequently, he led the use of solid polymer electrolytes and developed lithium-metal-polymer batteries with vanadium oxide as the cathode in 1978. Michel successfully conducted research in new salts topics based on delocalized anions of the sulfonimide family in 1986; his research areas included 1) organic electrode materials, i.e., innovations in redox-active organics, which included poly quinones and aromatic dicarboxylates, and 2) carbon “nano painting” process that has made LiFePO4@C the safest cathode in 2002. Because Michel has co-authored over 500 publications and many patents, it is impractical to fully review his outstanding contributions in electrochemistry in this work. This work is limited to a few of his contributions pertaining to the evolution of electrochemical energy storage. We further discussed different routes envisioned for further progress in rechargeable batteries.