Tetrasubstituted copper phthalocyanines: Correlation between liquid crystalline properties, films alignment and sensing properties

Abstract

Copper phthalocyanines (CuPc) containing alkylthio (-S(CH 2) n CH 3 , n=7 and 15), alkyloxy-(-O(CH 2) n CH 3 , n=7 and 15) and polyoxo (-O(CH 2 CH 2 O) 3 CH 3 and-S(CH 2 CH 2 O) 3 CH 3) substituents were synthesized and investigated to reveal the effects of substituents type (alkylthio, alkyloxy and polyoxo) and the type of the connecting heteroatom (oxygen or sulphur) on the mesogenic properties, films alignment and sensing behaviour. The liquid crystalline properties of these phthalocyanines were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction techniques. The structure and morphology of spun thin films of copper phthalocyanine derivatives were studied by the UV-Vis and Raman spectroscopies as well atomic force microscopy. The sensing properties of CuPc films were studied by the measurement of conductivity change upon interaction with ammonia in the range 10-50 ppm. All investigated films of CuPc derivatives display thermotropic columnar mesomorphism. It was shown that the films with polyoxo-(-O(CH 2 CH 2 O) 3 CH 3 and-S(CH 2 CH 2 O) 3 CH 3) substituents as well as with alkylthio-S(CH 2) n CH 3 (n=7) substituents, which are liquid crystalline at room temperature, form ordered films with a random planar alignment of columns. Their films exhibit the better sensor performance with the maximal sensor response for the films of CuPc containing (-S(CH 2 CH 2 O) 3 CH 3) substituents.

Hierarchical Self‐Assembly of Tetrakis(1‐pyrenyl)porphyrins into Microscopic Petals and Flowers with Ultrasensitive Room‐Temperature NO2 Sensing in a Broad Humidity Range

“…The highly stable and selective sensing behaviour of 1 and 2 should likely be attributed to the weak physical absorption between H 2 S or NH 3 and pyrenyl‐ substituted porphyrins in addition to a close stacking of the porphyrin molecules on the surface of the substrate, which might act as a kinetic barrier against H 2 S and NH 3 to interacting with semiconducting layer. The similar shielding effect of the substituents on the analyte has been reported for tetra‐substituted copper phthalocyanines, trifluoroethoxy‐substituented tris(phthalocyaninato) europium complex and a dimeric phthalocyanine‐containing quintuple‐decker …”

Phthalocyanines: Alternative Sensitizers of TiO2 to be Used in Photocatalysis

“…to obtain metal complex phthalocyanines. Also, the benzene rings located at the periphery of the structure can be substituted with several functional groups to obtain several substituted phthalocyanines [49][50][51][52][53][54][55].…”

Theoretical investigation of the interaction between the metal phthalocyanine [MPc]a (M = Sc, Ti, and V; a = –1, 0, and +1) complexes and formaldehyde

“…For example, Rossignol et al [19] studied the detection of the NH 3 and O 3 gases in the range of 20 to 200 ppm by a cobalt phthalocyanine (CoPc) sensor. Moreover, there is a lot of research on the detection of NO 2 and NH 3 with metal phthalocyanines (M=Pd, Co, Cu, Mg, Ti, Ni, Zn) [20][21][22][23][24]. It is important to mention that a well-known phthalocyanine complex of titanium and vanadium is the metal-oxo complex (MOPc) with M 4+ redox state (M=Ti and V) [25,26].…”