Alexander S. Romanov

Stannyl Derivatives of Naphthalene Diimides and Their Use in Oligomer Synthesis

2-Stannyl and 2,6-distannyl naphthalene diimides (NDIs) can be synthesized through the palladium-catalyzed reaction of the appropriate bromo derivatives with hexabutylditin. The utility of these precursors in palladium catalyzed cross-coupling reactions is demonstrated by the synthesis of bi- and ter-NDI derivatives, UV-vis, cyclic voltammetry, and n-channel organic field-effect transistor data for which are compared to those of the monomeric parent NDI.

n‐Doping of Organic Electronic Materials Using Air‐Stable Organometallics: A Mechanistic Study of Reduction by Dimeric Sandwich Compounds

Several 19-electron sandwich compounds are known to exist as 2×18-electron dimers. Recently it has been shown that, despite their air stability in the solid state, some of these dimers act as powerful reductants when co-deposited from either the gas phase or from solution and that this behavior can be useful in n-doping materials for organic electronics, including compounds with moderate electron affinities, such as 6,13-bis[tri(isopropyl)silylethynyl]pentacene (3). This paper addresses the mechanisms by which the dimers of 1,2,3,4,5-pentamethylrhodocene (1u2009b(2)), (pentamethylcyclopentadienyl)(1,3,5-trialkylbenzene)ruthenium (alkyl=Me, 2 a(2); alkyl=Et, 2 b(2)), and (pentamethylcyclopentadienyl)(benzene)iron (2 c(2)) react with 3 in solution. Vis/NIR and NMR spectroscopy, and X-ray crystallography indicate that the products of these solution reactions are 3(·-) salts of the monomeric sandwich cations. Vis/NIR kinetic studies for the Group 8 dimers are consistent with a mechanism whereby an endergonic electron transfer from the dimer to 3 is followed by rapid cleavage of the dimer cation. NMR crossover experiments with partially deuterated derivatives suggest that the C-C bond in the 1 b(2) dimer is much more readily broken than that in 2 a(2); consistent with this observation, Vis/NIR kinetic measurements suggest that the solution reduction of 3 by 1 b(2) can occur by both the mechanism established for the Group 8 species and by a mechanism in which an endergonic dissociation of the dimer is followed by rapid electron transfer from monomeric 1 b to 3.

2,6-Diacylnaphthalene-1,8:4,5-bis(dicarboximides): synthesis, reduction potentials, and core extension.

2,6-Diacyl derivatives of naphthalene-1,8:4,5-bis(dicarboximide)s have been synthesized via Stille coupling reactions of the corresponding 2,6-distannyl derivative with acyl halides. Reaction of these diketones with hydrazine gave phthalazino[6,7,8,1-lmna]pyridazino[5,4,3-gh][3,8]phenanthroline-5,11(4H,10H)-dione fused-ring derivatives. The products were characterized by UV-vis absorption spectroscopy and electrochemistry, modeled using density functional theory calculations, and, in some cases, studied and compared using single-crystal X-ray diffraction.

Insight into the structures of [M(C(5)H(4)I)(CO)(3)] and [M(2)(C(12)H(8))(CO)(6)] (M = Mn and Re) containing strong I...O and pi(CO)-pi(CO) interactions.

The compounds tricarbonyl(eta(5)-1-iodocyclopentadienyl)manganese(I), [Mn(C(5)H(4)I)(CO)(3)], (I), and tricarbonyl(eta(5)-1-iodocyclopentadienyl)rhenium(I), [Re(C(5)H(4)I)(CO)(3)], (III), are isostructural and isomorphous. The compounds [mu-1,2(eta(5))-acetylenedicyclopentadienyl]bis[tricarbonylmanganese(I)] or bis(cymantrenyl)acetylene, [Mn(2)(C(12)H(8))(CO)(6)], (II), and [mu-1,2(eta(5))-acetylenedicyclopentadienyl]bis[tricarbonylrhenium(I)], [Re(2)(C(12)H(8))(CO)(6)], (IV), are isostructural and isomorphous, and their molecules display inversion symmetry about the mid-point of the ligand C[triple-bond]C bond, with the (CO)(3)M(C(5)H(4)) (M = Mn and Re) moieties adopting a transoid conformation. The molecules in all four compounds form zigzag chains due to the formation of strong attractive I...O [in (I) and (III)] or pi(CO)-pi(CO) [in (I) and (IV)] interactions along the crystallographic b axis. The zigzag chains are bound to each other by weak intermolecular C-H...O hydrogen bonds for (I) and (III), while for (II) and (IV) the chains are bound to each other by a combination of weak C-H...O hydrogen bonds and pi(Csp(2))-pi(Csp(2)) stacking interactions between pairs of molecules. The pi(CO)-pi(CO) contacts in (II) and (IV) between carbonyl groups of neighboring molecules, forming pairwise interactions in a sheared antiparallel dimer motif, are encountered in only 35% of all carbonyl interactions for transition metal-carbonyl compounds.

Structures of the conformational isomers and polymorph modifications of N-substituted 2,6-(E,E)-bis(ferrocenylidene)piperid-4-ones: photo- and electrochemically induced E/Z isomerization

Four N-substituted 2,6-(E,E)-bis(ferrocenylidene)piperid-4-ones (NH 1, NMe 2, NEt 3, NCH2Ph 4) were prepared by aldol condensation between ferrocenecarbaldehyde and two equivalents of N-substituted piperid-4-ones with high yields. The N-protonated compounds were obtained by reaction with HBF4·Et2O acid. The molecular structures of compounds 2, 3, 2·HBF4 and 4·HBF4 were confirmed by X-ray diffraction analysis and three types of conformational isomers were elucidated. Two polymorph modifications were found for compound 2·HBF4. The electron transfer properties of the complexes were examined by electrochemical and spectroelectrochemical techniques. Complexes 1–4 undergo a reversible process of two-electron oxidation and partially reversible one-electron reduction. The photo- and electrochemically induced E/Z isomerisation of the complexes was monitored by UV-vis and 1H NMR spectroscopy.

Monohalogenated ferrocenes C(5)H(5)FeC(5)H(4)X (X = Cl, Br and I) and a second polymorph of C(5)H(5)FeC(5)H(4)I.

The structures of the three title monosubstituted ferrocenes, namely 1-chloroferrocene, [Fe(C(5)H(5))(C(5)H(4)Cl)], (I), 1-bromoferrocene, [Fe(C(5)H(5))(C(5)H(4)Br)], (II), and 1-iodoferrocene, [Fe(C(5)H(5))(C(5)H(4)I)], (III), were determined at 100 K. The chloro- and bromoferrocenes are isomorphous crystals. The new triclinic polymorph [space group P-1, Z = 4, T = 100 K, V = 943.8 (4) A(3)] of iodoferrocene, (III), and the previously reported monoclinic polymorph of (III) [Laus, Wurst & Schottenberger (2005). Z. Kristallogr. New Cryst. Struct. 220, 229-230; space group Pc, Z = 4, T = 100 K, V = 924.9 A(3)] were obtained by crystallization from ethanolic solutions at 253 and 303 K, respectively. All four phases contain two independent molecules in the unit cell. The relative orientations of the cyclopentadienyl (Cp) rings are eclipsed and staggered in the independent molecules of (I) and (II), while (III) demonstrates only an eclipsed conformation. The triclinic and monoclinic polymorphs of (III) contain nonbonded intermolecular I...I contacts, causing different packing modes. In the triclinic form of (III), the molecules are arranged in zigzag tetramers, while in the monoclinic form the molecules are arranged in zigzag chains along the a axis. Crystallographic data for (III), along with the computed lattice energies of the two polymorphs, suggest that the monoclinic form is more stable.

Monohalogenated ferrocenes C5H5FeC5H4X (X = Cl, Br and I) and a second polymorph of C5H5FeC5H4I

The structures of the three title monosubstituted ferrocenes, namely 1-chloroferrocene, [Fe(C(5)H(5))(C(5)H(4)Cl)], (I), 1-bromoferrocene, [Fe(C(5)H(5))(C(5)H(4)Br)], (II), and 1-iodoferrocene, [Fe(C(5)H(5))(C(5)H(4)I)], (III), were determined at 100 K. The chloro- and bromoferrocenes are isomorphous crystals. The new triclinic polymorph [space group P-1, Z = 4, T = 100 K, V = 943.8 (4) A(3)] of iodoferrocene, (III), and the previously reported monoclinic polymorph of (III) [Laus, Wurst & Schottenberger (2005). Z. Kristallogr. New Cryst. Struct. 220, 229-230; space group Pc, Z = 4, T = 100 K, V = 924.9 A(3)] were obtained by crystallization from ethanolic solutions at 253 and 303 K, respectively. All four phases contain two independent molecules in the unit cell. The relative orientations of the cyclopentadienyl (Cp) rings are eclipsed and staggered in the independent molecules of (I) and (II), while (III) demonstrates only an eclipsed conformation. The triclinic and monoclinic polymorphs of (III) contain nonbonded intermolecular I...I contacts, causing different packing modes. In the triclinic form of (III), the molecules are arranged in zigzag tetramers, while in the monoclinic form the molecules are arranged in zigzag chains along the a axis. Crystallographic data for (III), along with the computed lattice energies of the two polymorphs, suggest that the monoclinic form is more stable.