Fully Oxidized and Mixed-Valent Polyoxomolybdates Structured by Bisphosphonates with Pendant Pyridine Groups: Synthesis, Structure and Photochromic Properties

Inorganics

Olivier Oms²  Tarik Benali²  Jérome Marrot²  Pierre Mialane²  Marin Puget³  Hélène Serier-Brault³  Philippe Deniard³  Rémi Dessapt³  Anne Dolbecq²  Greta Ricarda Patzke¹ 

[1] Institut Lavoisier de Versailles, UMR8180, Université de Versailles St Quentin en Yvelines, 45 Avenue des Etats Unis, 78035 Versailles cedex, France;;Institut Lavoisier de Versailles, UMR8180, Université de Versailles St Quentin en Yvelines, 45 Avenue des Etats Unis, 78035 Versailles cedex, France; E-Mails:;Institut des Matériaux Jean-Rouxel, Université de Nantes, CNRS, 2 Rue de la Houssinière, BP 32229, 44322 Nantes cedex, France; E-Mails:

关键词: bisphosphonate;    hydrogen bonds;    molybdenum;    photochromism;    polyoxometalate;   

DOI  :  10.3390/inorganics3020279

来源: mdpi

【 摘 要 】

Hybrid organic-inorganic polyoxometalates (POMs) were synthesized in water by the reaction of a Mo^VI precursor with bisphosphonate ligands functionalized by pyridine groups. The fully oxidized POM [(Mo^VI₃O₈)₂(O)(O₃PC(O)(C₃H₆NH₂CH₂C₅H₄NH)PO₃)₂]⁴⁻ has been isolated as water insoluble pure Na salt (NaMo₆(Ale-4Py)₂) or mixed Na/K salt (NaKMo₆(Ale-4Py)₂) and their structure solved using single-crystal X-ray diffraction. The mixed-valent complex [(Mo^V₂O₄)(Mo^VI₂O₆)₂{O₃PC(O)(C₃H₆N(CH₂C₅H₄N)₂(Mo^VIO₃))PO₃}₂]⁸⁻ was obtained as an ammonium salt (NH₄Mo₆(AlePy₂Mo)₂), in the presence of a reducing agent (hydrazine). ³¹P NMR spectroscopic studies in aqueous media have allowed determining the pH stability domain of NH₄Mo₆(AlePy₂Mo)₂. NaMo₆(Ale-4Py)₂ and NaKMo₆(Ale-4Py)₂ exhibit remarkable solid-state photochromic properties in ambient conditions. Under UV excitation, they develop a very fast color-change from white to deep purple and proved to be the fastest photochromic organoammonium/POM systems. The coloration kinetics has been fully quantified for both salts and is discussed in light of the hydrogen-bonding networks.

【 授权许可】

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