Photochromic properties of polyoxotungstates with grafted spiropyran molecules.
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 (1)H and (31)P 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.
Institut Parisien de Chimie Moléculaire, IPCM, UMR CNRS 7201, Université Pierre et Marie Curie, UPMC Univ Paris 06, 4 Place Jussieu, Case 42, F-75005 Paris, France.
Arnaud
A
Parrot
Guillaume
G
Izzet
Lise-Marie
LM
Chamoreau
Anna
A
Proust
Olivier
O
Oms
Anne
A
Dolbecq
Khadija
K
Hakouk
Houda
H
El Bekkachi
Philippe
P
Deniard
Rémi
R
Dessapt
Pierre
P
Mialane