Reinvestigation of hybrid organic–inorganic materials based on molybdate and piperazininum cations: Influence of the synthesis conditions on the chemical composition and characterizations of the photochromic properties

The reactivity of the [Mo7O24]6− anion towards the structure directing-reagent piperazine (pipz) has been investigated and new synthetic routes to achieve the known (H2pipz)3[Mo8O27] 1, (H2pipz)[Mo3O10]·H2O 2, and (H2pipz)[Mo5O16] 3 molybdenum(VI) containing compounds are proposed. The role of the pH on the stabilization of the different compounds and their interconversion pathways is discussed. Compounds 1 and 2 show photochromic behavior under UV excitation, related to the particular organization of the organic component around the mineral framework. Their optical properties are reported and commented.

Graphical abstractThree organic–inorganic hybrid materials have been prepared from the investigations of the [Mo7O24]6−/piperazine system in hydrothermal conditions. The role of the pH on the stabilization of the different polyoxomolybdate blocks in the materials i.e. 1∞[Mo3O10]2− and 1∞[Mo8O27]6− chains and 2∞[Mo5O16]2− layer has been investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide