Double-Decker Phthalocyanines: Spectral Redox Properties and Sensor Elements Based on Them

2014 ◽  
pp. 139-152
2020 ◽  
Author(s):  
Radu Talmazan ◽  
Klaus R. Liedl ◽  
Bernhard Kräutler ◽  
Maren Podewitz

We analyze the mechanism of the topochemically controlled difunctionalization of C60 and anthracene, where an anthracene molecule is transferred from one C60 monoadduct to another one under exclusive formation of equal amounts of C60 and the difficult to make antipodal C60 bisadduct. Our herein disclosed dispersion corrected DFT studies show the anthracene transfer to take place in a synchronous retro Diels-Alder/Diels-Alder reaction: an anthracene molecule dissociates from one fullerene under formation of an intermediate, while already undergoing stabilizing interactions with both neighboring fullerenes, facilitating the reaction kinetically. In the intermediate, a planar anthracene molecule is sandwiched between two neighboring fullerenes and forms equally strong "double-decker" type pi-pi stacking interactions with both of these fullerenes. Analysis with the distorsion interaction model shows that the anthracene unit of the intermediate is almost planar with minimal distorsions. This analysis sheds light on the existence of noncovalent interactions engaging both faces of a planar polyunsaturated ring and two convex fullerene surfaces in an unprecedented 'inverted sandwich' structure. Hence, it sheds light on new strategies to design functional fullerene based materials.<br>


1981 ◽  
Vol 46 (5) ◽  
pp. 1237-1247
Author(s):  
Zdeněk Prokop ◽  
Karel Setínek

The catalyst containing redox sites in addition to acid functional groups was prepared by sulphonation of a macroporous chloromethylated styrene-divinylbenzene copolymer with concentrated sulphuric acid at elevated temperatures. Its activity was tested for the oxidation of 2-propanol by molecular oxygen at 120 °C and was found to be comparable to that of the iridium on carbon catalyst.Neutralisation of acid functional groups by alkali metal led to proportional decrease in the oxidation activity. The results of EPR spectroscopic study of these catalysts show that the redox properties of the polymer are caused by carbon clusters which are capable of electron exchange.


1980 ◽  
Vol 45 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Adéla Kotočová ◽  
Ulrich Mayer

The solvation effect of a number of nonaqueous polar solvents was studied on the oxidation-reduction properties of the [Co(en)3]3+-[Co(en)3]2+ system. Interactions of these ions with the solvent molecules are discussed in terms of their coordination, which is accompanied by a specific interaction of the Lewis acid-base type, namely formation of a hydrogen bond between the interacting particles. This is the main controlling factor of the redox properties of the studied system.


2001 ◽  
Vol 66 (7) ◽  
pp. 1062-1077 ◽  
Author(s):  
Maarten J. Bakker ◽  
Tapani A. Pakkanen ◽  
František Hartl

Electrochemical properties of tetrahedral clusters [H2Ru2Rh2(CO)12], [HRuRh3(CO)12] and [Rh4(CO)12] were investigated in order to evaluate the influence of metal core composition in the series [H4-xRu4-xRhx(CO)12] (x = 0-4). The cluster [H3Ru3Rh(CO)12] was not available in sufficient quantities. As reported for [H4Ru4(CO)12], electrochemical reduction of the hydride-containing clusters [H2Ru2Rh2(CO)12] and [HRuRh3(CO)12] also results in (stepwise) loss of hydrogen, producing the anions [HRu2Rh2(CO)12]-, [Ru2Rh2(CO)12]2- and [RuRh3(CO)12]-. These anions can also be prepared from the neutral parent clusters via chemical routes. Electrochemical reduction of [Rh4(CO)12] does not result in the formation of any stable tetranuclear anion. Instead, [Rh5(CO)15]- and [Rh6(CO)15]2- are the major reduction products detected in the course of IR spectroelectrochemical experiments. Most likely, these cluster species are formed from the secondary CO-loss product [Rh4(CO)11]2- by fast redox condensation reactions. Their reoxidation regenerates parent [Rh4(CO)12], together with some [Rh6(CO)16]. Unlike [H4Ru4(CO)12] that undergoes photochemical CO-dissociation, [H2Ru2Rh2(CO)12] and [Rh4(CO)12] are completely photostable in neat hexane and dichloromethane as well as in the presence of oct-1-ene.


2019 ◽  
Vol 23 (11n12) ◽  
pp. 1603-1615
Author(s):  
Chandana Pal ◽  
Isabelle Chambrier ◽  
Andrew N. Cammidge ◽  
A. K. Sharma ◽  
Asim K. Ray

In-plane electrical characteristics of non-peripherally octyl(C[Formula: see text]H[Formula: see text]- and hexyl(C[Formula: see text]H[Formula: see text]-substituted liquid crystalline (LC) double decker lanthanide bisphthalocyanine (LnPc[Formula: see text] complexes with central metal ions lutetium (Lu), and gadolinium (Gd) have been measured in thin film formulations on interdigitated gold (Au) electrodes for the applied voltage ([Formula: see text] range of [Formula: see text]. The conduction mechanism is found to be Ohmic within the bias of [Formula: see text] while the bulk limited Poole–Frenkel mechanism is responsible for the higher bias. The compounds show individual characteristics depending on the central metal ions, substituent chain lengths and their mesophases. Values of 67.55 [Formula: see text]cm[Formula: see text] and 42.31 [Formula: see text]cm[Formula: see text] have been obtained for room temperature in-plane Ohmic conductivity of as-deposited octyl lutetium (C[Formula: see text]LuPc[Formula: see text] and hexyl gadolinium (C[Formula: see text]GdPc[Formula: see text] films, respectively while C[Formula: see text]GdPc[Formula: see text] films exhibit nearly two orders of magnitude smaller conductivity. On annealing at 80[Formula: see text]C, Ohmic conductivities of C[Formula: see text]LuPc[Formula: see text] and C[Formula: see text]GdPc[Formula: see text] are found to have increased but the conductivity of C[Formula: see text]GdPc[Formula: see text] decreased by more than one order of magnitude to 1.5 [Formula: see text]cm[Formula: see text]. For physical interpretation of the charge transport behavior of these three molecules, their UV-vis optical absorption spectra in the solution and in as-deposited and annealed solid phases and atomic force microscopy study have been performed. It is believed that both orientation and positional reorganizations are responsible, depending upon the size of the central ion and side chain length.


Langmuir ◽  
2011 ◽  
Vol 27 (14) ◽  
pp. 9068-9068 ◽  
Author(s):  
Asuman C. Kucuk ◽  
Jun Matsui ◽  
Tokuji Miyashita

2015 ◽  
Vol 54 (13) ◽  
pp. 6203-6215 ◽  
Author(s):  
Sanchita Kundu ◽  
Dhrubajyoti Mondal ◽  
Kisholoy Bhattacharya ◽  
Akira Endo ◽  
Daniele Sanna ◽  
...  

2007 ◽  
Vol 68 (4) ◽  
pp. 879-892 ◽  
Author(s):  
Johan Sagemark ◽  
Tobias H. Elgán ◽  
Thomas R. Bürglin ◽  
Catrine Johansson ◽  
Arne Holmgren ◽  
...  
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document