Rimma N. Lyubovskaya

New molecular complexes of fullerenes C60 and C70 with tetraphenylporphyrins [M(tpp)], in which M=H2, Mn, Co, Cu, Zn, and FeCl.

New molecular complexes of fullerenes C60 and C70 with tetraphenylporphyrins [M(tpp)] in which M-H2, MnII, CoII, CuII, ZnII and Fe(III)Cl, have been synthesised. Crystal structures of two C60 complexes with H2TPP, which differ only in the number of benzene solvated molecules, and C60 and C70 complexes with [Cu(tpp)] have been studied. The fullerene molecules form a honeycomb motif in H2TPP.2C60. 3C6H6, puckered graphite-like layers in H2TPP.2C60.4C6H6, zigzag chains in [Cu(tpp)].C70.1.5C7H8.0.5C2HCl3 and columns in [Cu(tpp)]2.C60. H2TPP has van der Waals contacts with C60 through nitrogen atoms and phenyl groups. Copper atoms of the [Cu(tpp)] molecules are weakly coordinated with C70, but form no shortened contacts with C60. The formation of molecular complexes with fullerenes affects the ESR spectra of [M(tpp)] (M = Mn, Co and Cu). [Mn(tpp)] in the complex with C70 lowers its spin state from S = 5/2 to S = 1/2, whereas [Co(tpp)] and [Cu(tpp)] change the constants of hyperfine interaction. ESR, IR, UV-visible and X-ray photoelectron spectroscopic data show no noticeable charge transfer from the porphyrinate to the fullerene molecules.

Investigation of poly(p-phenylene) obtained by electrochemical oxidation of benzene in a BuPyClAlCl3 melt

Abstract Poly( p -phenylene) has been obtained by electrochemical oxidation of benzene in a BuPyClAlCl 3 melt. The conductivity of the fresh film is 10 – 100 S/cm. Even when the film is stored in a dry inert atmosphere, its conductivity is reduced. Electrochemical properties and IR and ESR spectra have been investigated. The polymer has an average chain length of 29 – 30 units.

Organic Solar Cells with Semitransparent Metal Back Contacts for Power Window Applications

To provide truly transparent solar cells for power window applications, both semiconductor and electrode materials have to have a very low absorption over as much of the visible spectrum as possible. We present some promising visible transparent semiconductor combinations, namely zinc-phthalocyanine or zinc-naphthalocyanine together with soluble fullerenes in conjunction with a method for obtaining highly transparent thin metal films by tuning the interference patterns in the multilayer organic solar cells structure. In an optimal combination, solar cells with an efficiency of about 0.5 % and a peak transparency of more than 60 % in the visible part of the spectrum were fabricated.

Complexation of pyrrolidinofullerenes and zinc-phthalocyanine in a bilayer organic solar cell structure

Bilayer organic solar cells were prepared using zinc-phthalocyanine (ZnPc) and a novel, highly soluble pyrollidinofullerene bearing three chelating pyridyl groups (PyF). The formation of supramolecular complexes between the two compounds is indicated by a significantly increased solubility of ZnPc in dichloromethane upon addition of the PyF. Spin-coating a film of PyF on a vacuum-evaporated film of ZnPc results in a solar cell yielding short circuit current (Isc) densities of 3mA∕cm2 and open-circuit voltages (Voc) of about 0.4V under 100mW∕cm2 simulated AM1.5 illumination. Solar cells prepared by substituting the PyF with a fullerene derivative forming no complexes with ZnPc show significantly lower photovoltaic conversion efficiencies.

A Two-Dimensional Organic Metal Based on Fullerene†

We report the synthesis and studies of the physical properties of the first two-dimensional (2D) fullerene organic metal to have 2D layers with a honeycomb arrangement of C60C , (MDABCO)·TPC·(C60C ) (1); we employed a multicomponent and molecular symmetry synthetic approach, starting from the N-methyldiazabicyclooctane cation (MDABCO) and triptycene (TPC). Compound 1 is a fascinating example of a material composed of only light elements (C, H, N) that exhibits a metallic state down to 1.9 K. Salts of fullerene C60 with a number of different inorganic cations have previously shown metallic or superconducting properties. Among the fullerene metals, the best known families are MC60 salts (M = K, Rb, Cs), which contain linearly polymerized C60C , and superconducting M3C60 salts (M = alkali metals), obtained by doping C60 with alkali metals, which have transition temperatures (Tc) of up to 38 K. [1–4] As metal cations expand the three-dimensional (3D) lattice of the initial C60 framework, M3C60 salts exhibit 3D metallic conductivity, whereas MC60 salts are either 3D (when M = K) or quasi-1D metals (when M = Rb or Cs). 2D fullerene metals have not yet been obtained, whilst the various possible ways of modifying MxC60 salts have almost been exhausted. The idea of obtaining purely organic molecular metals or superconductors from fullerenes has remained unrealized, despite being considered for many years. None of the C60C salts of organic cations have exhibited metallic properties. The salt (NMe4 )·(C60C )·THF1.5 showed rather high conductivity, yet was a semiconductor. By synthesizing organic molecular crystals from C60 and organic electron donor molecules, it is possible to produce conductors with unique structures and properties. We have developed a multicomponent approach for synthesizing ionic fullerene compounds that enables the synthesis of ionic fullerene solids DI ·DII·C60C of various structures. 7] DI + is a small, strong donor or cation that ionizes C60 and determines its charged state, whereas DII is a large, neutral molecule that defines the crystal packing of the complex. In order to exhibit metallic properties, the fullerene sublattice should have a close-packed structure. However, C60C radical anions have a strong tendency for dimerization, and when they are allowed to approach each other they normally form diamagnetic single-bonded (C60 )2 dimers. [7–9] In this study, by choosing DII molecules with suitable spatial geometry and size, we were able to synthesize a complex with a close-packed fullerene 2D sublattice in which the C60C monomers preferentially form a 2D honeycomb network of C60C rather than undergo dimerization. We expected that TPC (Figure 1), which forms molecular complexes with C60, [10, 11] would offer a suitable geometrical space and spatial regulation as the DII component for C60C ions in ionic multicomponent complexes. Indeed, it forms hexagonal layers with voids that accommodate foreign cations, such as MDABCO (DI ), in the first key–keyhole relationship (Figure 1a). Docking C60C into the periodic hollow sites in the (MDABCO)·TPC network (second key–keyhole relationship; Figure 1a,b) leads to hexagonal packing of the fullerene layers without dimerization of the C60C monomers. We used diffusion to obtain good-quality single crystals of complex 1, which have a rhombohedral structure at 300 K. The C60C radical anions (the charged state was confirmed spectroscopically) formed uniform hexagonal close-packed layers of two types, A and B, which alternate with the (MDABCO)·TPC layers along the c axis (Figure 2a). In type A layers, the C60C radical anions are ordered and packed as shown in Figure 1, with the uncharged nitrogen atoms of the MDABCO cations arranged directly above the fullerene hexagons (Figure 2a,b). Layers of type B show dynamic disorder of the C60C anions at 300 K, with methyl groups of MDABCO cations slightly penetrating into the periodic hollow sites in the hexagonal packing of disordered C60C ions (Figure 2a,c). In both types of layers, each C60C has six fullerene neighbors with an equal center-to-center distance of 10.073(1) at 300 K, which decreases to 9.967(1) at 185 K. In type B layers, the disorder of C60C ions at 300 K could be described as flipping between three symmetrically related orientations of C60C with 1/3 occupancy for each [*] D. V. Konarev, Prof. R. N. Lyubovskaya Institute of Problems of Chemical Physics RAS Chernogolovka, Moscow region, 142432 (Russia) E-mail: konarev@icp.ac.ru

The formation of a single-bonded (C70−)2 dimer in a new ionic multicomponent complex of cyclotriveratrylene: (Cs+)2(C70−)2·CTV·(DMF)7(C6H6)0.75

The molecular structure and properties of a single-bonded (C70−)2 dimer in a new ionic complex with cyclotriveratrylene (CTV): (Cs+)2·(C70−)2·CTV·(DMF)7·(C6H6)0.75 are presented.

New complexes of fullerenes C60 and C70 with organic donor DBTTF: synthesis, some properties and crystal structure of DBTTF . C60 . C6H6 (DBTTF = dibenzotetrathiafulvalene)

Abstract New complexes of fullerenes C 60 and C 70 with dibenzotetrathiafulvalene (DBTTF), DBTTF·C 60 ·C 6 H 6 , DBTTF·C 60 ·Py and DBTTF·C 70 ·C 6 H 6 , were obtained. The crystal structure of DBTTF·C 60 ·C 6 H 6 was determined. The arrangement of fullerene molecules is approximately simple cubic packing where each C 60 molecule is located in slightly distorted octahedral surrounding. DBTTF molecules have a concave conformation. X-ray photoelectron spectroscopy (XPS) and IR spectroscopy show only weak charge transfer in these compounds. A weak charge transfer band near 900 nm was found in the UV-Vis-NIR absorption spectrum of DBTTF·C 60 ·C 6 H 6 single crystals. DBTTF molecules are coordinated on C 60 ones by π-π and n-π interactions. It was shown that the steric discrepancy between DBTTF and C 60 molecules does not provide favourable conditions for charge transfer in the DBTTF·C 60 ·C 6 H 6 complex.

Synthesis, Structures, and Properties of Crystalline Salts with Radical Anions of Metal‐Containing and Metal‐Free Phthalocyanines

Radical anion salts of metal-containing and metal-free phthalocyanines [MPc(3-)](·-), where M = Cu(II), Ni(II), H2, Sn(II), Pb(II), Ti(IV)O, and V(IV)O (1-10) with tetraalkylammonium cations have been obtained as single crystals by phthalocyanine reduction with sodium fluorenone ketyl. Their formation is accompanied by the Pc ligand reduction and affects the molecular structure of metal phthalocyanine radical anions as well as their optical and magnetic properties. Radical anions are characterized by the alternation of short and long C-Nimine bonds in the Pc ligand owing to the disruption of its aromaticity. Salts 1-10 show new bands at 833-1041 nm in the NIR range, whereas the Q- and Soret bands are blue-shifted by 0.13-0.25 eV (38-92 nm) and 0.04-0.07 eV (4-13 nm), respectively. Radical anions with Ni(II), Sn(II), Pb(II), and Ti(IV)O have S = 1/2 spin state, whereas [Cu(II)Pc(3-)](·-) and [V(IV)OPc(3-)](·-) containing paramagnetic Cu(II) and V(IV)O have two S = 1/2 spins per radical anion. Central metal atoms strongly affect EPR spectra of phthalocyanine radical anions. Instead of narrow EPR signals characteristic of metal-free phthalocyanine radical anions [H2Pc(3-)](·-) (linewidth of 0.08-0.24 mT), broad EPR signals are manifested (linewidth of 2-70 mT) with g-factors and linewidths that are strongly temperature-dependent. Salt 11 containing the [Na(I)Pc(2-)](-) anions as well as previously studied [Fe(I)Pc(2-)](-) and [Co(I)Pc(2-)](-) anions that are formed without reduction of the Pc ligand do not show changes in molecular structure or optical and magnetic properties characteristic of [MPc(3-)](·-) in 1-10.

Dimerization of C60˙− in multi-component ionic complexes with bis(ethylenedithio)tetrathiafulvalene: (cation+)2·ET·(C60˙−)2

Two multi-component ionic complexes (cation+)2·ET·(C60˙−)2 comprising C60˙− radical anions, neutral bis(ethylenedithio)tetrathiafulvalene (ET) molecules and N-methyldiazabicyclooctane (1) or N,N-dimethylpyrrolidine (2) cations were obtained. At room temperature 1 involves monomeric nearly freely rotating C60˙− radical anions arranged in zigzag double chains passing along the a axis and separated by ET molecules and cations. Dimerization is observed in 1 at 280–250 K within C60˙− pairs with 9.922 A center-to-center interfullerene distances. It was shown that dimerization temperatures are dependent on the initial distance between the C60˙− anions in the monomeric phase, and the shortest center-to-center interfullerene distance in 1 provides the highest dimerization temperature among ionic C60 complexes studied so far. The crystal structure of the dimeric phase was determined at 100 K. The (C60−)2 dimers are bound by one single bond of 1.589(2) A length with an interfullerene center-to-center distance of 9.288 A. The room temperature unit cell parameters of 2 are similar to those of 1 and dimerization is realized in this complex at 280–250 K. Dimerization is reversible in both complexes and results in the transition of the complexes from a paramagnetic to a diamagnetic state.

Organic Solar Cells: Structure, Materials, Critical Characteristics, and Outlook

This review surveys recent advances in the field of photovoltaic devices based on organic photoactive materials and used for converting solar energy into electricity. Different architectures of organic photovoltaic devices are considered: bilayer, bulk heterojunction, and tandem cells. Major groups of organic semiconductors are described together with some numerical data on their performance in solar cells. Possible ways of improving the efficiency of organic solar cells are discussed. The bibliography consists of 80 references.