Lutetium phthalocyanine explained

Lutetium phthalocyanine () is a coordination compound derived from lutetium and two phthalocyanines. It was the first known example of a molecule that is an intrinsic semiconductor.^{[1] [2]} It exhibits electrochromism, changing color when subject to a voltage.

Structure

is a double-decker sandwich compound consisting of a 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

, along with many substituted derivatives like the alkoxy-methyl derivative, 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 is red, whereas the reduced form 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]

Electrical properties

and other lanthanide phthalocyanines are of interest in the development of organic thin-film field-effect transistors.^{[3] [5]}

derivatives can be selected to change color in the presence of certain molecules, such as in gas detectors;^[2] for example, the thioether derivative changes from green to brownish-purple in the presence of NADH.^[6]

Notes and References

1. Belarbi . Z. . Sirlin . C. . Simon . J. . Andre . Jean Jacques . Electrical and magnetic properties of liquid crystalline molecular materials: lithium and lutetium phthalocyanine derivatives . The Journal of Physical Chemistry . November 1989 . 93 . 24 . 8105–8110 . 10.1021/j100361a026.
2. Trometer . M. . Even . R. . Simon . J. . Dubon . A. . Laval . J.-Y. . Germain . J.P. . Maleysson . C. . Pauly . A. . Robert . H. . Lutetium bisphthalocyanine thin films for gas detection . Sensors and Actuators B: Chemical . May 1992 . 8 . 2 . 129–135 . 10.1016/0925-4005(92)80169-X.
3. Bidermane . I. . Lüder . J. . Boudet . S. . Zhang . T. . Ahmadi . S. . Grazioli . C. . Bouvet . M. . Rusz . J. . Sanyal . B. . Eriksson . O. . Brena . B. . Puglia . C. . Witkowski . N. . Experimental and theoretical study of electronic structure of lutetium bi-phthalocyanine . The Journal of Chemical Physics . 21 June 2013 . 138 . 23 . 234701 . 10.1063/1.4809725 . 23802970 . 2013JChPh.138w4701B . en . 0021-9606.
4. Toupance . Thierry . Plichon . Vincent . Simon . Jacques . Substituted bis(phthalocyanines): electrochemical properties and probe beam deflection (mirage) studies . New Journal of Chemistry . 1999 . 23 . 10 . 1001–1006 . 10.1039/A905248H.
5. Wang . Jun . Wang . Haibo . Zhang . Jian . Yan . Xuanjun . Yan . Donghang . Organic thin-film transistors with improved characteristics using lutetium bisphthalocyanine as a buffer layer . Journal of Applied Physics . 15 January 2005 . 97 . 2 . 026106–026106–3 . 10.1063/1.1840093. 2005JAP....97b6106W .
6. Basova . Tamara . Gürek . Ayşe Gül . Ahsen . Vefa . Ray . Asim . Electrochromic lutetium phthalocyanine films for in situ detection of NADH . Optical Materials . 1 January 2013 . 35 . 3 . 634–637 . 10.1016/j.optmat.2012.10.017. 2013OptMa..35..634B .