SYNTHESIS AND FILM-FORMING PROPERTIES OF METAL-COMPLEXES OF OCTADECYLETHERS OF 5,10,15,20-TETRAKIS(4-HYDROXYPHENYL)PORPHYRIN

Metal complexes [Al(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd( II), and Pt(II)] of various octadecyl ethers of 5,10,15,20-tetrakis(4- hydroxyphenyl)porphyrin have been prepared and characterised. The meta lloporphyrins are examined for their ability to form layers using the Langmuir technique, and pressure-area isotherms are presented. Multila yers on glass substrates are made in suitable cases using the Langmuir -Blodgett method. Complexes of the tris(octadecyl) ether generally giv e films with favourable properties although the aluminium(III) complex , which is shown to be dimeric, does not. In certain cases where the p ure metalloporphyrin gives unsatisfactory results, the film can be imp roved using a stabiliser such as stearic acid. The absorption maxima o f the films are determined before and after exposure to sensor gases ( Cl2, HCl, NO2) and after further exposure to hydrazine vapour ('hydraz ine reset'), and compared with solution spectra.