A new route to polyoxometalates via mechanochemistry.

Mechanochemistry offers a new route to polyoxometalates (POMs) under mild conditions. The molybdenum isoPOM heptamolybdate and the molybdenum heteroPOMs of the Strandberg- and Keggin-type could be achieved from grinding together molybdenum oxide, potassium or ammonium carbonate and phosphate. The reactions were controlled by the stoichiometric ratio of the starting materials and the liquid used, with reaction times between 30 min and 3 h. In situ investigations of the syntheses reveal the formation of intermediates during the reactions. Their identification helps explaining the mechanism of formation of the intermediates as well as the final POMs.

Metastability and Seeding Effects in the Mechanochemical Hybrid Lead(II) Iodide Formation.

The mechanism for the mechanochemical synthesis of (C(NH2 )3 )3 PbI5 3 and (C(NH2 )3 )4 PbI6 4 and their conversion into each other is presented. We investigated the synthesis of 3 at different frequencies and energies using in situ powder X-ray diffraction. By splitting the reaction into single parts we could prove that the formation of 3 is simply dependent on the energy and mixing speed. The nucleation of 4 instead is slightly negative dependent on the energy but dependent on the mixing speed, while its growth is mostly independent of any influence. We were able to influence the reaction pathways by seeding the mixture with a small amount of powdery 4. The formation of 4 is very likely an auto-catalytic process. 3 instead is metastable. It can be stabilized by energy, which beside mechanochemistry can also be achieved by temperature. The results showcases the complex nature of mechanochemical reactions.

Monitoring polymer-assisted mechanochemical cocrystallisation through in situ X-ray powder diffraction.

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the investigation of polymer-assisted grinding reactions using in situ X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of the polymer additive used.

Insight into the Mechanochemical Synthesis and Structural Evolution of Hybrid Organic-Inorganic Guanidinium Lead(II) Iodides.

The in situ investigations of the mechanochemical synthesis of four hybrid organic-inorganic lead(II) iodides with the formula (C(NH2 )3 )n PbI2+n (n=1, 2, 3, and 4) are presented. Synchrotron X-ray diffraction data show that the four guanidinium lead(II) iodides easily convert into each other. Although the end product is dictated by the initial stoichiometry, complex pathways were found with different behaviors of the compounds in terms of nucleation, growth, and intermediate formation. This appears to be linked to the respective structural features of the different compounds, especially the connectivity of the inorganic framework and the strength of ionic interactions. High-temperature studies were conducted on compounds 1, 3, and 4 to reveal the new phases 1-II, 3-II, and 3-III. Unknown structures were solved from single-crystal analysis and powder X-ray diffraction.

Warming up for mechanosynthesis - temperature development in ball mills during synthesis.

We present a first direct measurement of the temperature during milling combined with in situ Raman spectroscopy monitoring. The data reveal a low temperature increase due to the mechanical impact and clear temperature increases as a consequence of the reaction heat. Based on the data, temperature rises as postulated in the magma plasma and hot spot theory can be excluded for soft matter milling syntheses.

The crystallisation of copper(ii) phenylphosphonates.

The crystal structures and syntheses of four different copper(ii) phenylphosphonates, the monophenylphosphonates α-, ß-, and γ-Cu(O3PC6H5)·H2O (α-CuPhPmH (1) ß-CuPhPmH (2) and γ-CuPhPmH (3)), and the diphosphonate Cu(HO3PC6H5)2·H2O (CuPhP2mH (4)), are presented. The compounds were synthesized from solution at room temperature, at elevated temperature, under hydrothermal conditions, and mechanochemical conditions. The structures of α-CuPhPmH (1) and CuPhP2mH (4) were solved from powder X-ray diffraction data. The structure of ß-CuPhPmH (2) was solved by single crystal X-ray analysis. The structures were validated by extended X-ray absorption fine structure (EXAFS) and DTA analyses. Disorder of the crystal structure was elucidated by electron diffraction. The relationship between the compounds and their reaction pathways were investigated by in situ synchrotron measurements.

The structure and in situ synthesis investigation of isomorphic mononuclear molecular metal phenylphosphonates.

We describe a fast and effective synthesis for molecular metal phosphonates. Isomorphic compounds [M(ii)(HO3PPh)2(H2O3PPh)2(H2O)2] (M = Mn (1), Co (2), Ni (3); Ph = C6H5) were obtained by grinding. The complexes are mononuclear compounds containing neutral and monodeprotonated phenylphosphonic acid and water as ligands. The crystal structures were determined using powder X-ray diffraction (PXRD) data and validated by extended X-ray absorption fine structure (EXAFS) data. Combined synchrotron XRD measurements and Raman spectroscopy were conducted for investigating the reactions in situ. Based on these data, the intermediates were characterized and the formation mechanism was derived.

Direct in†situ investigation of milling reactions using combined X-ray diffraction and Raman spectroscopy.

The combination of two analytical methods including time-resolved in situ X-ray diffraction (XRD) and Raman spectroscopy provides a new opportunity for a detailed analysis of the key mechanisms of milling reactions. To prove the general applicability of our setup, we investigated the mechanochemical synthesis of four archetypical model compounds, ranging from 3D frameworks through layered structures to organic molecular compounds. The reaction mechanism for each model compound could be elucidated. The results clearly show the unique advantage of the combination of XRD and Raman spectroscopy because of the different information content and dynamic range of both individual methods. The specific combination allows to study milling processes comprehensively on the level of the molecular and crystalline structures and thus obtaining reliable data for mechanistic studies.

Guías de práctica clínica de la Sociedad Española de Cardiología en pruebas de esfuerzo / Guidelines of the Spanish Society of Cardiology for clinical practice in exercise testing

La mayor parte de las pruebas de esfuerzo se realizan a pacientes adultos con cardiopatía isquémica en estudio o ya conocida. En los últimos años se ha producido la incorporación de las técnicas de imagen en este campo, mejorando así la información aportada por la prueba de esfuerzo convencional. Pero cada vez existen más situaciones que escapan a esta norma general, tanto en sujetos sanos (asintomáticos, atletas, discapacitados, etc.) como en pacientes con cardiopatías diferentes de la isquémica (insuficiencia cardíaca congestiva avanzada, hipertensión, trastornos del ritmo, cardiopatías congénitas etc.). Todos estos aspectos justifican un documento de consenso en España, necesariamente multidisciplinario. Este documento revisa en profundidad la metodología de las pruebas de esfuerzo convencionales, sin olvidar las realizadas con determinación de consumo de oxígeno. El papel de esta exploración en el manejo de la cardiopatía isquémica, así como las aplicaciones de las técnicas de imagen al campo de estrés, ocupan un lugar fundamental en esta revisión. Por último, se analiza la utilidad de las pruebas de esfuerzo en diversas cardiopatías no isquémicas y en diferentes poblaciones de sujetos sanos (AU)