Sven Holl

Natrium-Salze des Bipyridin-Dianions: Polymer [(bpy)2−{Na+(dme)}2]∞, Cluster [(Na8O)6 +Na+6(bpy)62−(tmeda)6] und Monomer [(bpy)2−{Na+(pmdta)}2]

Bipyridin, ein Arbeitspferd unter den Liganden der Komplexchemie, last sich mit Natrium zum Dianion reduzieren. Je nach Solvens kristallisieren verschiedenartige Natrium-Salze: Aus Dimethoxyethan/Toluol wird ein Polymer, aus Tetramethylethylendiamin/Benzol ein lipophil umhullter [Na14O]12 +-Cluster und aus Pentamethyldiethylentriamin ein monomeres Na2-bpy-Salz erhalten (siehe Strukturbild).

Wechselwirkungen in Molekülkristallen, 163 [1, 2]. Einfluß der Alkalimetall-Reduktionspotentiale auf die Bildung ihrer Kontaktionenmultipel mit Tetracen- und Decacylen-Polyanionen / Interaction in Molecular Crystals, 163 [ 1,2]. The Influence of Alkaline Metal Reduction Potentials on the Formation of their Contaction Multiples with Tetracene and Decacyclene Polyanions

The reduction of selected π-hydrocarbons tetracene and decacyclene by various alkaline metals allowed the crystallization and structure determination of the following five solvent separated or solvent shared contaction multiples: [Tetracene⊖⊖ (Na⊕Diglyme)2], [Tetracene⊖⊖ - (K⊕ Triglyme)2], [Decacyclene• ⊖] [Cs⊕ (Triglyme)2], [Decacyclene•⊖⊖⊖] [Na⊕ (DME)3]3, [Decacyclene⊖⊖⊖⊖ (K⊕Diglyme)4]. These alkaline salts contain a radicalanion M• ⊖ , dianions M⊖⊖ , a radicaltrianion M•⊖⊖⊖ , and a tetraanion M⊖⊖⊖⊖ generated by single or multiple electron transfer. Their structures are discussed in terms of the difference in alkaline metal reduction potentials, the powerful cation solvation, the effects of the anion charges and of the cation radii. Further aspects concern the solvent-shared or solvent-separated cation coordination to the anions, the polyion aggregation and for the radical trianion the experimentally proven and quantumchemically simulated Jahn/Teller distortion. Altogether the investigation adds facets to the knowledge of multielectrontransfer reactions and of selforganisation phenomena of alkaline salts.

Wechselwirkungen in Molekülkristallen, 167 [1, 2]. Kristallzüchtung und Strukturbestimmung von σ-Donator/Akzeptor- Komplexen zwischen 1,4-Dioxan und den Polyiod-Molekülen I2,I2C=CI2, (IC)4S sowie (IC)4NR (R = H, CH3) / Interaction in Molecular Crystals, 167 [1, 2]. C rystallization and Structure Determination of σ -Donor/Acceptor Complexes between 1,4-Dioxane and the Polyiodine Molecules I2,I2C=CI2, (IC)4S and (IC)4NR (R = H, CH3)

Abstract With 1,4-dioxane as the constant donor, five new donor/acceptor complexes with the polyiodine compounds I-I, I2C=CI2, tetraiodothiophene and two tetraiodopyrrole derivatives could be crystallized and their structures determined despite their decomposition in air. They provide interesting facets for selforganisation on crystallization: The 1,4-dioxane addition causes at best small structural changes of the polyiodine compounds. All adducts crystallize in chains of alternating donors and acceptors, which also staple separatedly. The direction of the contacts O···I depends on the incorporation of the 1,4-dioxane molecules into the iodine acceptor layers. The structural results correlate with those obtained for donor/acceptor complexes with organosulfur donors and, therefore, add to the rationalization of intermolecular interactions.

Wechselwirkungen in Molekülkristallen, 180 [1, 2]. σ-Donator/Akzeptor-Komplexe {S(CI)4···X⊖ }(X⊖ = I⊖ , SCN⊖ ) von Tetraiodthiophen in Tetra(n-butyl)ammoniumhalogenid-Salzen/Interaction in Molecular Crystals, 180 [1, 2]. -Donor/Acceptor Complexes {S(CI)4···X⊖} (X⊖= I⊖, SCN⊖ of Tetraiodothiophene in Tetra(n-butyl)ammonium Halide Salts

Two donor/acceptor complexes between halide anion donors and the tetraiodothiophene acceptor with tetra(n-butyl)ammonium countercations, {(H9C4)4N⊕X⊖···(IC)4Sg (X⊖ = I⊖, SCN⊖) could be crystallized from acetone solutions of the components R4N⊕X

Wechselwirkungen in Molekülkristallen, 179 [1, 2]. σ-Donator/Akzeptor-Komplexe {I2C=CI2···X⊖ } (X⊖ = Cl⊖ , Br⊖ , I⊖ , SCN⊖ ) von Tetraiodethen in Tetra(n-butyl)ammoniumhalogenid-Salzen / Interaction in Molecular Crystals, 179 [1, 2]. σ-Donor/Acceptor Complexes {I2C=CI2···X⊖} (X⊖= Cl⊖, Br⊖, I⊖, SCN⊖) of Tetraiodoethene in Tetra(n-butyl)ammonium Halide Salts

and (IC)4S by using low-gradient techniques. Low temperature structural studies revealed that the molecule packing motifs are layers of halide anion/tetraiodothiophene patterns penetrated each by one of the four R4N⊕ n-butyl chains. The structure discussion emphasizes observed regularities such as the preferred coordination X⊖···I by the polyiodo acceptor molecules to dimers, followed by the additional aggregation to layers and the inclusion of one n-butyl chain fromeach voluminous R4N⊕ countercation. Especially this effect could be an essential crystallization principle for the fascinating self-assembly comprising a halide anion and a polyiodo acceptor molecule.

Wechselwirkungen in Molekülkristallen, 166 [1, 2]. Polyiod-Moleküle I2C=CI2, (IC)4S, (IC)4NH, (IC)4N-CH3 und HCI3: Strukturbestimmung nach Kristallzüchtung oder durch Dichtefunktionaltheorie-Berechnung / Interaction in Molecular Crystals, 166 [1, 2], Polyiodo Molecules I2C=CI2, (IC)4S, (IC)4 NH, (IC)4N-CH and HCI3: Structure Determination Following Crystallization or by Density Functional Theory Calculation

Four donor/acceptor complexes between halide anion donors and the tetraiodoethene acceptor molecule with tetra(n-butyl)ammoniumcountercations, {(H9C4)4N⊕X⊖···I2C=CI2)} (X⊖ = Cl⊖, Br⊖, I⊖, SCN⊖) could be crystallized from acetone solutions of the components R4N⊕X⊖ and I2C=CI2 by using low gradient techniques, and their structures determined at low temperature. Their molecule packing motif are layers of halide anion/tetraiodoethene patterns, which are penetrated by one of the four R4N⊕ n-butyl chains. The structure comparison, including analogous ones from an extensive Cambridge Structural Database search, discusses the geminal or vicinal addition to dimer subunits {X⊖···I2C=CI2}2 as well as their ribbon formation via additional contacts X⊖···I, and the effects of the voluminous R4N⊕ countercations. Altogether some light is shedded on essential facets of the fascinating self-assembly comprising an electron-rich halide anion and a polyiodo acceptor molecule.

Sodium Salts of the Bipyridine Dianion: Polymer [(bpy)2−{Na+(dme)}2]∞, Cluster [(Na8O)6+Na+6(bpy)62−(tmeda)6], and Monomer [(bpy)2−{Na+(pmdta)}2]

Abstract The structures of tri-and tetraiodo-substituted carbon compounds are determined either experimentally by X-Ray Structure Analysis or, because crystallization of tetraiodothiophene could not be achieved, approximated by Density Functional Theory optimization of structural data from a donor/acceptor complex. The structures show noteworthy details such as a second polymorph of tetraiodoethene crystallized by sublimation or herringbone crystal packing patterns of tetraiodopyrrole derivatives. All molecular geometries are discussed and compared based on relativistic density functional theory calculations with 6 -31G* basis sets including iodine pseudopotentials. They reproduce even finer structural details due to van der Waals repulsion of the bulky iodo substituents. Natural Bond Orbital (NBO) charge distributions suggest positive partial charges at all iodine centers with the strongest polarization Cδ㊀ → Iδ㊉ in HCI3, which contains well over 97% iodine.