Synthesis, interface (Au/M2Pc2/p-Si), electrochemical and electrocatalytic properties of novel ball-type phthalocyanines

Abstract

The phthalodinitrile derivative (3) was prepared by the reaction of 4,4'-(octahydro-4,7-methano-5H-inden-5-ylidene)bisphenol (1) and 4-nitrophthalonitrile (2) with dry DMF as the solvent in the presence of the base K(2)CO(3) by the method of nucleophilic substitution of an activated nitro group in an aromatic ring. The template reaction of 3 with the corresponding metal salts gave the novel bi-nuclear ball-type metallophthalocyanines, MPcs {M = Co (4), Cu (5), Zn (6)}. Newly synthesized compounds were characterized by elemental analysis, UV-vis, FT-IR (ATR), MALDI-TOF mass and (1)H-NMR spectroscopy techniques. The electronic spectra exhibit an intense π→π* transition of characteristic Q and B bands of the Pc core. The dielectric properties and interface between the spin coated films of 4-6 and a p-type silicon substrate have been studied by fabricating metal-insulator-semiconductor capacitors. The results indicated that the frequency dependence of the dielectric permittivity, ε'(ω), exhibits non-Debye type relaxation for all the temperatures investigated. The ac conductivity results indicated that the conduction mechanism can be explained by a hopping model at low temperatures (<430 K) and a free band conduction mechanism at high temperatures (≥430 K). The density of interface state calculations on these novel compounds showed that the combination of Au/4/p-Si is a promising structure with a high dielectric constant and a low interface trap density suitable for metal-oxide-semiconductor devices. The electrochemical properties of the Pc complexes were examined by cyclic voltammetry, differential voltammetry and controlled potential coulometry on platinum in non-aqueous media. The complexes showed ring-based and/or metal-based mixed-valence behaviours as a result of the remarkable interaction between the two Pc rings and/or metal centres. The mixed-valence splitting values for the complexes suggested that the mixed valence species are considerably stable. The Vulcan XC-72(VC)/Nafion(Nf)/4 modified glassy carbon electrode showed much a higher catalytic performance towards oxygen reduction than those of VC/Nf/5 and VC/Nf/6 modified ones.

Impedance Spectroscopy and Dielectric Relaxation of Imidazole-Substituted Palladium(II) Phthalocyanine (ImPdPc) for Organic Solar Cells

“…Nevertheless, the distortion polarization results from electronic and atomic polarization. 71 , 72 Figures 17 and 18 depict the frequency dependence of the dielectric constant (ε′) and dielectric loss (ε″) of the PdPc(Imz) 4 pellet at different temperatures.…”

Synthesis, characterization, OFET and electrochemical properties of novel dimeric metallophthalocyanines

“…covalently linked porphyrine dimers in the literature. 26 However, it should be noted that the catalytic performance of previously reported ball-type cobalt Pcs with dicumarol, 13 4,4′-(octahydro-4,7-methano-5H-inden-5-ylidene)bisphenol, 12 dithioerytritol, 23a cyclopentyl disilanoxy-polyhedral, oligomeric silsesquioxanes, 23a and pentaerythritol, 8b,c bridging units for ORR was higher than that of 3. This can be attributed to the difference in the distance between the two CoPc units and the flexibility of the molecules.…”

“…The electrocatalytic activities of the ball-type Pc complexes 2 and 3 towards oxygen reduction reaction (ORR) was also tested since some articles reported by our group showed that electrocatalytic activities of ball-type dinuclearmetallo Pcs for ORR are encouraging in general for applicability in fuel cells. 8b,c, 12,13,23 The ring and disk polarization curves of a rotating ring disk electrode (RRDE), disk of which was modified by a mixture of the relevant Pc complex with Vulcan XC-72 (VC) and Nafion (Nf ), in O 2 -saturated 0.5 M H 2 SO 4 aqueous electrolyte solution (Fig. 7), have been monitored and then the catalytic performance has been characterized the by the onset potential (E o ) where the oxygen reduction current begins to increase, the limiting diffusion disk current density (J L ) and…”

“…Table 2 lists the electrocatalytic performances of 2 and 3. It also includes the catalytic activities of some previously reported ball-type dinuclear cobalt Pcs with dicumarol, 13 4,4′-(octahydro-4,7-methano-5H-inden-5-ylidene)bisphenol, 12 dithioerytritol, 23a cyclopentyldisilanoxy-polyhedral oligomeric silsesquioxanes, 23b and pentaerythritol, 8b,c bridging units for comparison. The ORR catalyzed by 3 displays two reduction waves (Fig.…”

“…4 Furthermore, a large number of a new class of dimeric complexes, ball type Pcs which are covalently bonded with each other were reported. Owing to different bridges such as tert-butylcalix [4]arene, 5 1,1′-methylenedinaphthalen-2-ol, 6 pentaerythritol 7 and its different derivatives, 8 1a,8b-dihydronaphtho [b]naphthofuro- [3,2-d]-furan-7,10-diol, 9 phenolphthalein, 10 9,9′-bis(4-hydroxyphenyl)fluorine, 11 4,4′-(octahydro-4,7-methano-5H-inden-5-ylidene)-/ bisphenol, 12 and dicumarol, 13 syntheses of various ball-type metallophthalocyanines (MPcs) were achieved.…”