Observation of the influence of dipolar and spin frustration effects on the magnetocaloric properties of a trigonal prismatic {Gd-7} molecular nanomagnet

Pineda EM, Lorusso G, Zangana KH, et al. Observation of the influence of dipolar and spin frustration effects on the magnetocaloric properties of a trigonal prismatic {Gd-7} molecular nanomagnet. CHEMICAL SCIENCE. 2016;7(8):4891-4895.We report the synthesis and structure of a molecular {Gd-7} cage of the formula ((Pr2NH2)-Pr-i)(6)[Gd-7(mu(3)-OH)(3)(CO3)(6)((O2CBu)-Bu-t)(12)] which has crystallographic C-3h symmetry. Low temperature specific heat and adiabatic demagnetization experiments (the latter achieving temperatures below 100 mK), lead to the observation of the effects of both intramolecular dipolar interactions and geometric spin frustration. The dipolar interaction leads to a massive rearrangement of energy levels such that specific heat and entropy below 2 K are strongly modified while magnetic susceptibility and magnetization above 2 K are not affected. The consequences of these phenomena for low temperature magnetocaloric applications are discussed

Synthesis, Crystal Structures, and Magnetic Properties of Lanthanide (III) Amino-Phosphonate Complexes

Two isostructural lanthanide amino-phosphonate complexes [Ln10(μ3-OH)3(µ-OH)(CO3)2(O2CtBu)15(O3PC6H10NH2)3(O3PC6H10NH3)2(H2O)2][Et2NH2] (Ln = Gd(III), 1 and Tb(III), 2) have been obtained through reflux reactions of lanthanide pivalates with, a functionalized phosphonate, (1-amino-1-cyclohexyl)phosphonic acid and diethylamine (Et2NH) in acetonitrile (MeCN) at 90 °C. Both compounds have been characterized with elemental analysis, single-crystal X-ray diffraction methods, and magnetic measurements. The molecular structure of compounds 1 and 2 reveal two highly unsymmetrical complexes comprising ten lanthanide metal centers, where the lanthanide metal ion centers in the cages are linked through pivalate units and further interconnected by CPO3 tetrahedra to build the crystal structure. The magnetic behavior of 1 and 2 was investigated between ambient temperature and ca. 2 K, the magnetic measurements for compound 1 suggests antiferromagnetic interactions between the Gd(III) metal ion centers at low temperatures. The large number of isotropic Gd(III) ions comprising 1 makes it a candidate for magnetocaloric applications, thus the magnetocaloric properties of this molecular cage were investigated indirectly through isothermal magnetisation curves. The magnetic entropy change was found to be 34.5 J kg−1K−1, making 1 a plausible candidate in magnetic cooling applications

CCDC 1051263: Experimental Crystal Structure Determination

Related Article: Karzan H. Zangana, Eufemio Moreno Pineda, Richard E. P. Winpenny|2015|Dalton Trans.|44|12522|doi:10.1039/C5DT01786

CCDC 1051264: Experimental Crystal Structure Determination

Related Article: Karzan H. Zangana, Eufemio Moreno Pineda, Richard E. P. Winpenny|2015|Dalton Trans.|44|12522|doi:10.1039/C5DT01786

Simplified, fast, and efficient microwave assisted chemical recycling of poly (ethylene terephthalate) waste

The widespread adoption of chemical recycling of poly (ethylene terephthalate) (PET) is hampered by long reaction times, high energy consumption and the use of metal catalysts that are either toxic or cost prohibitive for industrial use. Herein, we report a simple PET glycolytic process that combines an environmentally friendly and cheap heterogenous catalyst, calcium oxide (CaO) with microwave irradiation to obtain the monomer bis(2-hydroxyethyl) terephthalate (BHET), which can be easily separated by crystallisation. After the process optimisation, depolymerisation of PET waste was achieved in 3.5 min under atmospheric pressure, to obtain highly crystalline BHET with a yield of 75%. To our knowledge, this is the fastest heterogeneous glycolytic process reported in the literature to-date, using a cheap and eco- friendly catalyst. Moreover, by using a heterogenous catalyst and avoiding the need for product precipitation by water addition, CaO and ethylene glycol materials were separated and reused, thus validating this protocol as a potential green and scalable route for PET recycling

CCDC 953480: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures

Octametallic 4f-phosphonate horseshoes

Zangana KH, Pineda EM, Schnack J, Winpenny REP. Octametallic 4f-phosphonate horseshoes. Dalton Transactions. 2013;42(39):14045-14048.Three octanuclear phosphonate clusters, formulated as [Ln(8)((O3PBu)-Bu-t)(6)(mu(3)-OH)(2)(H2O)(2)((HOBu)-Bu-i)((O2CBu)-Bu-t)(12)]((NH3Pr)-Pr-i)(2) (Ln = Gd, Dy and Tb), were synthesised by refluxing a mixture of pivalic acid ((HO2CBu)-Bu-t), Ln(NO3)(3)center dot 6H(2)O, tert-Butyl phosphonic acid ((H2O3PBu)-Bu-t) and isopropylamine ((PrNH2)-Pr-i) in isobutyl alcohol (BuOH)-Bu-i

Supplementary information files for: Simplified, fast, and efficient microwave assisted chemical recycling of poly (ethylene terephthalate) waste

Supplementary files for article: Simplified, fast, and efficient microwave assisted chemical recycling of poly (ethylene terephthalate) waste  The widespread adoption of chemical recycling of poly (ethylene terephthalate) (PET) is hampered by long reaction times, high energy consumption and the use of metal catalysts that are either toxic or cost prohibitive for industrial use. Herein, we report a simple PET glycolytic process that combines an environmentally friendly and cheap heterogenous catalyst, calcium oxide (CaO) with microwave irradiation to obtain the monomer bis(2-hydroxyethyl) terephthalate (BHET), which can be easily separated by crystallisation. After the process optimisation, depolymerisation of PET waste was achieved in 3.5 min under atmospheric pressure, to obtain highly crystalline BHET with a yield of 75%. To our knowledge, this is the fastest heterogeneous glycolytic process reported in the literature to-date, using a cheap and eco- friendly catalyst. Moreover, by using a heterogenous catalyst and avoiding the need for product precipitation by water addition, CaO and ethylene glycol materials were separated and reused, thus validating this protocol as a potential green and scalable route for PET recycling. </p