Low Dimensional and Frustrated Antiferromagnetic Interactions in Transition Metal Chloride Complexes with Simple Amine Ligands

This study reports the facile synthesis, crystal structures and magnetic properties of five new Mn, Co and Cu complexes with chloride and simple amine ligands. The four hydrazinium complexes are discrete in nature while the O-methylhydroxylamine phase contains edge-sharing chains bridged by chloride ligands. Investigation of the magnetic properties of these materials reveals that two of these materials, Co(NH3NH2)2(H2O)2Cl4 and Cu(NH2OCH3)2Cl2, exhibit interesting antiferromagnetic properties arising from their low dimensional structures. Co(NH3NH2)2(H2O)2Cl4 appears to exhibit significant 2D magnetic frustration while the magnetic susceptibilities of Cu(NH2OCH3)2Cl2 are well fitted by a one-dimensional chain model. The relationship between the strength of the magnetic coupling observed in these materials and their likely exchange pathways are also discussed

Spectroscopic Identification of Disordered Molecular Cations in Defect Perovskite‐like ALnLn(HCO2_2)(C2_2O4_4)1.5_{1.5} (LnLn = Tb‐Er) Phases

This work reports a new series of A$Ln$(HCO$_2$)(C$_2$O$_4$)$_{1.5}$ (A = [(CH$_3$)$_2$NH$_2$]$^+$ and Ln$^{3+}$ = Tb$^{3+}$-Er$^{3+}$) compounds made solvothermally. These ${Cmce}$ phases combine monovalent and divalent ligands, which enables a scarce combination of A$^+$ and B$^{3+}$ cations in a hybrid perovskite-like compound. The ratio of ligands leads to ordered anion vacancies, which alternate with oxalate linkers along the $c$-axis. The A-site cations are disordered and cannot be identified crystallographically, likely a result of the larger pores of these frameworks compared to the recently reported AEr(HCO$_2$)$_2$(C$_2$O$_4$) phases. Neutron and infrared spectroscopy, supported by elemental composition, enables these cations to be identified as [(CH$_3$)$_2$NH$_2$]$^+$ molecules. Magnetic property measurements suggest these materials have weak antiferromagnetic interactions but remain paramagnetic to 1.8 K

Enhancing the chemical flexibility of hybrid perovskites by introducing divalent ligands

Herein we report the synthesis and structures of [(CH$_3$)$_2$NH$_2$]Er(HCO$_2$)$_2$(C$_2$O$_4$) and [(NH$_2$)$_3$C]Er(HCO$_2$)$_2$(C$_2$O$_4$), in which the inclusion of divalent oxalate ligands allows for the exclusive incorporation of A$^+$ and B$^{3+}$ cations in an ABX$_3$ hybrid perovskite structure for the first time. We rationalise the observed thermal expansion of these materials, including negative thermal expansion, and find evidence for weak antiferromagnetic coupling in [(CH$_3$)$_2$NH$_2$]Er(HCO$_2$)$_2$(C$_2$O$_4$)

Proceedings of the I ndo‐ U.S. bilateral workshop on accelerating botanicals/biologics agent development research for cancer chemoprevention, treatment, and survival

With the evolving evidence of the promise of botanicals/biologics for cancer chemoprevention and treatment, an Indo‐U.S. collaborative Workshop focusing on “Accelerating Botanicals Agent Development Research for Cancer Chemoprevention and Treatment” was conducted at the Moffitt Cancer Center, 29–31 May 2012. Funded by the Indo‐U.S. Science and Technology Forum, a joint initiative of Governments of India and the United States of America and the Moffitt Cancer Center, the overall goals of this workshop were to enhance the knowledge (agents, molecular targets, biomarkers, approaches, target populations, regulatory standards, priorities, resources) of a multinational, multidisciplinary team of researcher's to systematically accelerate the design, to conduct a successful clinical trials to evaluate botanicals/biologics for cancer chemoprevention and treatment, and to achieve efficient translation of these discoveries into the standards for clinical practice that will ultimately impact cancer morbidity and mortality. Expert panelists were drawn from a diverse group of stakeholders, representing the leadership from the National Cancer Institute's Office of Cancer Complementary and Alternative Medicine (OCCAM), NCI Experimental Therapeutics (NExT), Food and Drug Administration, national scientific leadership from India, and a distinguished group of population, basic and clinical scientists from the two countries, including leaders in bioinformatics, social sciences, and biostatisticians. At the end of the workshop, we established four Indo‐U.S. working research collaborative teams focused on identifying and prioritizing agents targeting four cancers that are of priority to both countries. Presented are some of the key proceedings and future goals discussed in the proceedings of this workshop. With the evolving evidence of the promise of botanicals/biologics for cancer chemoprevention and treatment, the proceedings of the Indo‐U.S. collaborative Workshop represent one of the most contemporary issues in Cancer Medicine .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96353/1/cam442.pd

Proceedings of the I ndo‐ U.S. bilateral workshop on accelerating botanicals/biologics agent development research for cancer chemoprevention, treatment, and survival

With the evolving evidence of the promise of botanicals/biologics for cancer chemoprevention and treatment, an Indo‐U.S. collaborative Workshop focusing on “Accelerating Botanicals Agent Development Research for Cancer Chemoprevention and Treatment” was conducted at the Moffitt Cancer Center, 29–31 May 2012. Funded by the Indo‐U.S. Science and Technology Forum, a joint initiative of Governments of India and the United States of America and the Moffitt Cancer Center, the overall goals of this workshop were to enhance the knowledge (agents, molecular targets, biomarkers, approaches, target populations, regulatory standards, priorities, resources) of a multinational, multidisciplinary team of researcher's to systematically accelerate the design, to conduct a successful clinical trials to evaluate botanicals/biologics for cancer chemoprevention and treatment, and to achieve efficient translation of these discoveries into the standards for clinical practice that will ultimately impact cancer morbidity and mortality. Expert panelists were drawn from a diverse group of stakeholders, representing the leadership from the National Cancer Institute's Office of Cancer Complementary and Alternative Medicine (OCCAM), NCI Experimental Therapeutics (NExT), Food and Drug Administration, national scientific leadership from India, and a distinguished group of population, basic and clinical scientists from the two countries, including leaders in bioinformatics, social sciences, and biostatisticians. At the end of the workshop, we established four Indo‐U.S. working research collaborative teams focused on identifying and prioritizing agents targeting four cancers that are of priority to both countries. Presented are some of the key proceedings and future goals discussed in the proceedings of this workshop. With the evolving evidence of the promise of botanicals/biologics for cancer chemoprevention and treatment, the proceedings of the Indo‐U.S. collaborative Workshop represent one of the most contemporary issues in Cancer Medicine .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96353/1/cam442.pd

A New Avenue to Relaxor-like Ferroelectric Behaviour Found by Probing the Structure and Dynamics of [NH3NH2]Mg(HCO2)3

The field of relaxor ferroelectrics has long been dominated by ceramic oxide materials exhibiting large polarisations with temperature and frequency dependence. Intriguingly, the dense metal-organic framework (MOF) [NH3NH2]Mg(HCO2)3 was reported as one of the first coordination frameworks to exhibit relaxor-like properties. This work clarifies the origin of these relaxor-like properties through re-examining its unusual phase transition using neutron single crystal diffraction, along with solid-state NMR and quasielastic neutron scattering studies. This reveals that the phase transition is caused by the partial re-orientation of NH3NH2 within the pores of the framework, from lying in the planes of the channel at lower temperatures to along the channel direction above the transition temperature. The transition occurs via a dynamic process such that the NH3NH2 cations can slowly interconvert between parallel and perpendicular orientations, with an estimated activation energy of 60 kJ mol-1. Furthermore these studies are consistent with proton hopping between the hydrazinium cations oriented along the channel direction via a proton site intermediate. This suggests the ferroelectric properties of [NH3NH2]Mg(HCO2)3 likely driven by a hydrogen bonding mechanism. The relaxor behaviour is proposed to be the result of polar regions, which likely fluctuate due to increased cation dynamics at high temperature. The combination of cation reorientation and proton hopping fully describes this material’s relaxor-like behaviour, suggesting a route to future design of non-oxide-based relaxor ferroelectrics

Lectotypification of Senecio biligulatus W. W. Sm.

A lectotype is designated for Senecio biligulatus W. W. Sm. (Asteraceae)