Photochromic Properties of Polyoxotungstates with Grafted Spiropyran Molecules

Arnaud Parrot (1, 2) , Guillaume Izzet (1) , Lise-Marie Chamoreau (1) , Anna Proust (1) , Olivier Oms (2) , Anne Dolbecq (2) , Khadija Hakouk (3) , Houda El Bekkachi (3) , Philippe Deniard (3) , Remi Dessapt (3) , Pierre Mialane (2)

1 IPCM - Institut Parisien de Chimie Moléculaire
2 ILV - Institut Lavoisier de Versailles
3 IMN - Institut des Matériaux Jean Rouxel

The first systems associating in a single molecule polyoxotungstates (POTs) and photochromic organic groups have been elaborated. Using the (TBA)4[PW11O39{Sn(C6H4I)}] precursor, two hybrid organic-inorganic species where a spiropyran derivative (SP) has been covalently grafted onto a {PW11Sn} fragment via a Sonogashira coupling have been successfully obtained. Alternatively, a complex containing a silicotungstate {PW11Si2} unit connected to two spiropyran entities has been characterized. The purity of these species has been assessed using several techniques, including 1H and 31P NMR spectroscopy, mass spectrometry, and electrochemical measurements. The optical properties of the hybrid materials have been investigated both in solution and in the solid state. These studies reveal that the grafting of SPs onto POTs does not significantly alter the photochromic behavior of the organic chromophore in solution. In contrast, these novel hybrid SP-POT materials display highly effective solid-state photochromism from neutral SP molecules initially nonphotochromic in the crystalline state. The photoresponses of the SP-POT systems in the solid state strongly depend on the nature and the number of grafted SP groups.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Arnaud Parrot, Guillaume Izzet, Lise-Marie Chamoreau, Anna Proust, Olivier Oms, et al.. Photochromic Properties of Polyoxotungstates with Grafted Spiropyran Molecules. Inorganic Chemistry, 2013, 52 (19), pp.11156. ⟨10.1021/ic401380a⟩. ⟨hal-00980500⟩