Transition-Metal Dependent Cation Disorder in the Chiral Cubic AB(HCO2)3 Metal-Organic Frameworks (A = Li or Na, B = Mn or Co)

This study examines the crystal structures of the AB(HCO2)3 (A = Li or Na and B = Mn or Co) metal-organic frameworks, which we find to adopt a chiral cubic P213 structure. This shows that the Li containing formates are isostructural with their Na analogues, extending the phase stability of this chiral architecture. The Mn containing compounds have a magnetic sublattice similar to ?-Mn, long of interest due to its highly frustrated antiferromagnetic coupling. In contrast the Co formates appear to have partially disordered alkali and transition metal cations, which prevents the formation of a clean ?-Mn-like magnetic sublattice. We have also re-examined the magnetic properties of NaMn(HCO2)3 finding it to be a simple paramagnet down to 2 K with only weak antiferromagnetic coupling

Three Coordination Frameworks with Copper Formate based Low Dimensional Motifs: Synthesis, Structure and Magnetic Properties

In this study we report the synthesis, crystal structures and magnetic properties of three frameworks wherein Cu cations are bridged by formate linkers into one-dimensional motifs. One of these compounds, Cu2(HCO2)3(C3N2H4)4(NO3), contains a ladder motif but remains paramagnetic to 2 K. This is likely because of the longer superexchange pathway along its chains due to the orientation of the Jahn-Teller axis of its Cu cations. In contrast Cu(HCO2)(NO3)(NH3)2 and Cu(HCO2)(ClO4)(NH3)2 feature Cu(HCO2) chains in which the Jahn-Teller axis is oriented perpendicular to the chain direction; these exhibit antiferromagnetic order below 12 and 7 K, respectively. Their magnetic susceptibilities are well fitted by a one-dimensional chain model but further examination of their magnetic properties reveals significant inter-chain magnetic coupling and a lack of spin dynamics. This suggests that these transitions correspond to the emergence of long-range magnetic order, highlighting the importance of detailed studies of frameworks containing low dimensional motifs to gain a deeper understanding of their magnetic behaviour

A Symbiotic Supramolecular Approach to the Design of Novel Amphiphiles with Antibacterial Properties Against MSRA

Herein, we identify Supramolecular Self-associating Amphiphiles (SSAs) as a novel class of antibacterials with activity towards Methicillin-resistant Staphylococcus aureus. Structure-activity relationships have been identified in the solid, solution and gas phases. Finally, we show that when supplied in combination, SSAs exhibit increased antibacterial efficacy against these clinically relevant microbes

Implications of the solubility of trivalent lanthanides in A Al2 O4 (A=Ca, Sr, and Ba) for their role in phosphors

The technique of standard addition in combination with powder X-ray diffraction was used to identify and quantify the amount of Ln3+ segregating into secondary phases from Ln3+ doped alkaline earth aluminates. Results indicate that Ln3+ ions are more soluble in Ca Al2 O4 than Sr Al2 O4 and Ba Al2 O4, with this being rationalized by the structural details of the A sites. These results indicate that the enhancement of the luminescence afterglow obtained by doping A Al2 O4: Eu2+ samples with Ln3+ ions is a result of much lower doping levels than previously thought. © International Centre for Diffraction Data

Phase segregation in mixed Nb-Sb double perovskites Ba2LnNb1-xSbxO6

The phase composition of two series of mixed Nb5+-Sb5+ double perovskites formed between the pairs Ba2EuNbO6-Ba2PrSbO6 and Ba2NdSbO6-Ba2NdNbO6 have been studied using synchrotron X-ray powder diffraction methods. In both series extensive phase segregation is observed demonstrating limited solubility of Sb5+ in these Nb5+ perovskites, irrespective of the precise structures of the double perovskite. Evidence for a monoclinic I2/m phase in the series formed between tetragonal I4/m Ba2EuNbO6 and rhombohedral R over(3, -) Ba2EuNbO6 is presented. It is postulated that this phase segregation is a consequence of competing bonding requirements of the Nb5+ and Sb5+ cations associated with their electronic configurations. © 2007 Elsevier Inc. All rights reserved

Magnetocaloric and Thermal Expansion Property Data for Inorg. Chem. 2022, 61, 12, 4957–4964

This collection contains the raw magnetometry, thermal expansion data and crystallographic information files (CIFs) associated with the publication by Doheny et al (2022) entitled "Investigations of the Magnetocaloric and Thermal Expansion Properties of the Ln3(adipate)4.5(DMF)2 (Ln = Gd–Er) Framework Series"

Structural studies of oxygen deficient lanthanide containing double perovskites

Several double perovskite compounds of the type Ba2NdB�O6-δ (B�=Sn4+, Nb5+ and Sb5+) were synthesised. Room temperature neutron diffraction patterns were obtained in order to determine the precise structure of these compounds. It was found that monoclinic Ba2NdSnO5.5 and Ba2NdNbO6 and rhombohedral Ba2NdSbO6 all featured only out-of-phase tilting. The structures of each of these three compounds revealed consistent overbonding of the Nd3+ cations most likely as a result of the significant size difference between the Nd3+ ions and B� cations. Crown Copyright © 2006

Lanthanide distribution in some doped alkaline earth aluminates and gallates

High-resolution neutron and synchrotron X-ray powder diffraction studies are reported for the six oxides AB2O4 (A=Ca2+, Sr2+ and Ba2+ and B=Al3+ and Ga3+). These oxides all adopt a stuffed tridymite type structure, the precise nature of which depends on both the A- and B-type cations. Bond valence calculations reveal a range of values for the various A-type cations, in all cases at least one site is significantly underbonded. Conversely the tetrahedral B-type sites invariably exhibit unexceptional bond valencies. Attempts to dope the oxides with various lanthanides to the 1% level invariably resulted in some segregation into alternate phases located at the grain boundaries. The identity of the impurity phases is presented and the importance of bond valencies in understanding this segregation is highlighted

Neutron diffraction study of the magnetic structures of manganese succinate Mn(C4H4O4): A complex inorganic-organic framework

The antiferromagnetic structures of the Mn succinate framework, Mn(C 4H4O4), have been determined using neutron diffraction. The structure comprises alternating layers containing chains of edge-sharing Mn (II) O6 octahedra and sheets of corner-sharing Mn (II) O6 octahedra, respectively, with a layer separation of �7.5. At 10 K the edge-sharing MnO6 octahedral chains order antiferromagnetically into a collinear sinusoidal spin structure with a propagation vector k2 = (0,-0.5225,0), in which individual edge-sharing MnO6 chains are ferromagnetically ordered. The sheets of corner-sharing MnO6 octahedra order magnetically at 6 K, adopting the antiferromagnetic structure expected for a square arrangement of cations with a propagation vector k8 = (-1,0,1). The ordering of these sheets at a lower temperature than the chains is consistent with their longer nearest-neighbor superexchange pathway. The magnetic structure of the edge-sharing layers is unaffected by the 6 K phase transition, indicating that the orderings of the two different layers are essentially independent of each other. © 2010 The American Physical Society

Structural phase transitions and crystal chemistry of the series Ba2LnBâ?²O6 (Ln=lanthanide and Bâ?²=Nb5+ or Sb5+)

The structures of 28 compounds in the two series Ba2LnSbO6 and Ba2LnNbO6 have been examined using synchrotron X-ray and in selected cases neutron powder diffraction at, below and above ambient temperature. The antimonate series is found to undergo a sequence of phase transitions from monoclinic to rhombohedral to cubic symmetry with both decreasing ionic radii of the lanthanides and increasing temperature. Compounds in the series Ba2LnNbO6, on the other hand, feature an intermediate tetragonal structure instead of the rhombohedral structure exhibited by the antimonates. This difference in symmetry is thought to be caused by Ï?-bonding in the niobates that is absent in the antimonates. The bonding environments of the cations in these compounds have also been examined with overbonding of the lanthanide and niobium cations being caused by the unusually large B-site cations. © 2006 Elsevier Inc. All rights reserved