Strategies to Achieve Stable Manganese Oxyfluorides by Tuning the Reactivity of Pure Molecular Fluorine.

Thanks to their high initial electrochemical properties and broad compositional flexibility, lithium-rich disordered rocksalt cathode-active materials including high-performance manganese-only materials appear as a potential replacement to the cobalt-based current market leader "NMC" material. The main issue with these materials is their lack of stability. However, recent works have identified bulk fluorination as a potential solution to stabilize these compounds. There is, however, a clear lack of diversity in fluorination agents used to synthesize these disordered rocksalts, as most publications used LiF, a very stable compound. To achieve manganese-only materials, manganese oxyfluorides represent promising precursors, but the literature reports only MnO3F and Mn2O2F9, which are both unstable and hazardous. The present study develops several strategies for synthesis and a tailored characterization methodology to explore the chemical space of direct fluorination of manganese oxide MnO with molecular fluorine and shows how to tune its reactivity to achieve a range of novel, safe, and finely tunable manganese oxyfluorides of general formula MnOFx, with x going from 0 to 1 synthesized via a fluorine insertion mechanism.

Facile Preparation of Chloride-Conducting Membranes: First Step towards a Room-Temperature Solid-State Chloride-Ion Battery.

Three types of chloride-conducting membranes based on polyvinyl chloride, commercial gelatin, and polyvinyldifluoride-hexafluoropolymer are introduced in this report. The polymers are mixed with chloride-containing salts, such as tetrabutylammonium chloride, and cast to form membranes. We studied the structural properties, thermal stability, and electrochemical response of the membranes to understand chloride migration and transport. Finally, the membranes are tested in a prototype solid-state chloride-ion battery setup. The feasibility of the membranes for their potential use in anion batteries is discussed.

Simple One-Pot Syntheses and Characterizations of Free Fluoride- and Bifluoride-Containing Polymers Soluble in Non-Aqueous Solvents.

One of the problems that arise with bifluoride- or fluoride-containing compounds is their poor solubility in non-aqueous solvents. We report herein a facile one-pot synthesis and the chemical analysis of fluoride/bifluoride-containing polymers, which are soluble in MeCN. Different polymers, such as Polyvinylacetate or Polyethylene imine and saccharides, such as maltodextrin, were complexed with ammonium (bi)fluoride using hydrogen bonds to form the desired (bi)fluoride-containing compounds. The newly formed hydrogen bonding (bi)fluoride-doped polymer matrices were analyzed using infrared and nuclear magnetic resonance spectroscopies, and X-ray diffraction. The promising materials also underwent impedance spectroscopy, conductivity measurements and preliminary tests as electrolytes for room temperature fluoride ion batteries along with an analysis of their performance.

CFA-2 and CFA-3 (Coordination Framework Augsburg University-2 and -3); novel MOFs assembled from trinuclear Cu(I)/Ag(I) secondary building units and 3,3',5,5'-tetraphenyl-bipyrazolate ligands.

The syntheses of H2-phbpz, [Cu2(phbpz)]·2DEF·MeOH (CFA-2) and [Ag2(phbpz)] (CFA-3) (H2-phbpz = 3,3',5,5'-tetraphenyl-1H,1'H-4,4'-bipyrazole) compounds and their crystal structures are described. The Cu(I) containing metal-organic framework CFA-2 crystallizes in the tetragonal crystal system, within space group I4(1)/a (no. 88) and the following unit cell parameters: a = 30.835(14), c = 29.306(7) Å, V = 27 865(19) Å(3). CFA-2 features a flexible 3-D three-connected two-fold interpenetrated porous structure constructed of triangular Cu(I) subunits. Upon exposure to different kinds of liquids (MeOH, EtOH, DMF, DEF) CFA-2 shows pronounced breathing effects. CFA-3 crystallizes in the monoclinic crystal system, within space group P2(1)/c (no. 14) and the following unit cell parameters: a = 16.3399(3), b = 32.7506(4), c = 16.2624(3) Å, ß = 107.382(2)°, V = 8305.3(2) Å(3). In contrast to the former compound, CFA-3 features a layered 2-D three-connected structure constructed from triangular Ag(i) subunits. Both compounds are characterized by elemental and thermogravimetric analyses, single crystal structure analysis and X-ray powder diffraction, FTIR- and fluorescence spectroscopy. Preliminary results on oxygen activation in CFA-2 are presented and potential improvements in terms of framework robustness and catalytic efficiency are discussed.

Bis[(1,10-phenanthroline-κ(2)N,N')bis-(triphenyl-phosphane-κP)copper(I)] nona-deca-oxidohexa-molybdate(VI).

The title compound, [Cu(C(12)H(8)N(2))(C(18)H(15)P)(2)](2)[Mo(6)O(19)], was obtained by co-crystallization of the mixed-ligand copper complex cation (1,10-phenanthroline)bis-(triphenyl-phos-phane)copper(I), [Cu(phen)(PPh(3))(2)](+), with the Lindquist polyanion [Mo(6)O(19)](2-). The asymmetric unit consists of half a Lindquist anion and one [Cu(phen)(PPh(3))(2)](+) cationic complex. In the cation, there are intra-molecular π-π inter-actions [centroid-centroid distances = 3.617 (2) and 3.7272 (18) Å]. This inorganic-organic adduct is connected by C-H⋯O hydrogen bonds, forming a two dimensional network lying in the ab plane. These networks are connected by C-H⋯π inter-actions into a three-dimensional structure.

Bis(chlorido)(dimethyl-sulfoxide-κO)barium(II).

The title compound, [BaCl(2)(C(2)H(6)SO)], forms a Ba(6)Cl(9) cluster in which the BaCl(2) units are connected via dimethyl-sulfoxide (DMSO) and chloride bridges. The central Cl atom of the Ba(6)Cl(9) cluster is located on a threefold inversion axis and is coordinated octa-hedrally to six barium cations. In the crystal, the clusters are arranged in rows, which are inter-connected by the DMSO mol-ecules, forming a three-dimensional network.

Poly[di-µ-glycinato-copper(II)]: a two-dimensional coordination polymer.

The title coordination polymer, [Cu(C(2)H(4)NO(2))(2)](n), is two-dimensional and consists of a distorted octa-hedral copper coordination polyhedron with two bidentate glycine ligands chelating the metal through the O and N atoms in a trans-square-planar configuration. The two axial coordination sites are occupied by carbonyl O atoms of neighbouring glycine mol-ecules. The Cu-O distances for the axial O atoms [2.648 (2) and 2.837 (2) Å] are considerably longer than both the Cu-O [1.9475 (17) and 1.9483 (18) Å] and Cu-N [1.988 (2) and 1.948 (2) Å] distances in the equatorial plane, which indicates a strong Jahn-Teller effect. In the crystal, the two-dimensional networks are arranged parallel to (001) and are linked via N-H⋯O hydrogen bonds, forming a three-dimensional arrangement.

From alkaline earth ion aggregates via transition metal coordination polymer networks towards heterometallic single source precursors for oxidic materials.

Heterometallic oxides are used as materials in many applications, e.g. from ferroelectrics to superconductors. Making these compounds usually requires high temperatures and long reaction times. Molecular precursors may contribute to render their processing shorter and accessible at lower temperatures, thus cheaper in energy and time. In this review article, different approaches toward oxide materials will be shown, starting with homometallic clusters and coordination polymers and highlighting recent results with heterometallic single source precursors. On the way to the latter, we came across many exciting results which themselves allowed applications in different fields. This work will give an overview on how these fields were brought together for the current mixed metallic compounds as precursors for heterometallic oxides.

Bis(2-amino-4-methyl-pyridinium) trans-diaqua-bis-(pyrazine-2,3-dicarboxyl-ato)cuprate(II) hexa-hydrate.

The title compound, (C(6)H(9)N(2))(2)[Cu(C(6)H(2)N(2)O(4))(2)(H(2)O)(2)]·6H(2)O, consists of a mononuclear trans-[Cu(pzdc)(2)(H(2)O)(2)](2-) dianion (pzdc is pyrazine-2,3-dicarboxyl-ate) and two [ampyH](+) cations (ampy is 2-amino-4-methyl-pyridine) with six water mol-ecules of solvation. The Cu(II) atom is hexa-coordinated by two pzdc groups and two water mol-ecules. The coordinated water mol-ecules are in trans-diaxial positions and the pzdc dianion acts as a bidentate ligand through an O atom of the carboxyl-ate group and the N atom of the pyrazine ring. There are diverse hydrogen-bonding inter-actions, such as N-H⋯O and O-H⋯O contacts, which lead to the formation of a three-dimensional supra-molecular architecture.

Multitopic ligand design: a concept for single-source precursors.

The multitopic ligand O,O'-bisnicotinic acid tetraethylene glycol, L, was designed for the coordination of two distinct types of metal ions. In this work, we describe how the O-donor part of L is used to coordinate to alkaline earth metal ions and that the N-donor atoms of L bind to group 11 elements. This makes L a suitable ligand for the combination of both metal ion types within the same compound. This concept will be exemplified by highlighting the pure Ca(2+) complexes, a Cu(+)-coordination polymer network, as well as the mixed-metal compound, which can be used as a single-source precursor for mixed-metal oxide materials.