LuPc2 is a double-decker sandwich compound consisting of a Lu3+ ion coordinated to two the conjugate base of two phthalocyanines. The rings are arranged in a staggered conformation. The extremities of the two ligands are slightly distorted outwards.[3] The complex features a non-innocent ligand, in the sense that the macrocycles carry an extra electron.[4] It is a free radical[1] with the unpaired electron sitting in a half-filled molecular orbital between the highest occupied and lowest unoccupied orbitals, allowing its electronic properties to be finely tuned.[3]
Properties
LuPc2, along with many substituted derivatives like the alkoxy-methyl derivative Lu[(C8H17OCH2)8Pc]2, can be deposited as a thin film with intrinsic semiconductor properties;[4] said properties arise due to its radical nature[1] and its low reduction potential compared to other metal phthalocyanines.[2] This initially green film exhibits electrochromism; the oxidized form LuPc+ 2 is red, whereas the reduced form LuPc− 2 is blue and the next two reduced forms are dark blue and violet, respectively.[4] The green/red oxidation cycle can be repeated over 10,000 times in aqueous solution with dissolved alkali metal halides, before it is degraded by hydroxide ions; the green/blue redox degrades faster in water.[4]
LuPc2 derivatives can be selected to change color in the presence of certain molecules, such as in gas detectors;[2] for example, the thioether derivative Lu[(C6H13S)8Pc]2 changes from green to brownish-purple in the presence of NADH.[6]
References
^ abcBelarbi, Z.; Sirlin, C.; Simon, J.; Andre, Jean Jacques (November 1989). "Electrical and magnetic properties of liquid crystalline molecular materials: lithium and lutetium phthalocyanine derivatives". The Journal of Physical Chemistry. 93 (24): 8105–8110. doi:10.1021/j100361a026.
^ abcTrometer, M.; Even, R.; Simon, J.; Dubon, A.; Laval, J.-Y.; Germain, J.P.; Maleysson, C.; Pauly, A.; Robert, H. (May 1992). "Lutetium bisphthalocyanine thin films for gas detection". Sensors and Actuators B: Chemical. 8 (2): 129–135. doi:10.1016/0925-4005(92)80169-X.
