Tetraphenylphosphonium bis(2‐thioxo‐1,3‐dithiole‐4,5‐dithiolato)aurate(III) acetone solvate and ethyltriphenylphosphonium bis(2‐thioxo‐1,3‐dithiole‐4,5‐dithiolato)aurate(III)

In the two title complexes, (C₂₄H₂₀P)[Au(C₃S₅)₂]·C₃H₆O, (I), and (C₂₀H₂₀P)[Au(C₃S₅)₂], (II), the Au^III atoms exhibit square‐planar coordinations involving four S atoms from two 2‐thioxo‐1,3‐dithiole‐4,5‐dithiolate (dmit) ligands. The Au—S bond lengths, ranging from 2.3057 (8) to 2.3233 (7) Å in (I) and from 2.3119 (8) to 2.3291 (10) Å in (II), are slightly smaller than the sum of the single‐bond covalent radii. In (I), there are two halves of independent Ph₄P⁺ cations, in which the two P atoms lie on twofold rotation axis sites. The Ph₄P⁺ cations and [Au(C₃S₅)₂]⁻ anions are interspersed as columns in the packing. Layers composed of Ph₄P⁺ and [Au(C₃S₅)₂]⁻ are separated by layers of acetone molecules. In (II), the [Au(C₃S₅)₂]⁻ anions and EtPh₃P⁺ counter‐cations form a layered arrangement, and the [Au(C₃S₅)₂]⁻ anions form discrete pairs with a long intermolecular Au...S interaction for each Au atom in the crystal structure.     

4,7‐Bis(4‐pyridyl­ethynyl)‐2,1,3‐benzo­thia­diazo­le and its dipyridinium diperchlorate

The title compound, C₂₀H₁₀N₄S, and its dipyridinium salt, 4,4′‐(2,1,3‐benzo­diazol‐4,7‐diyl­diethynyl)­dipyridinium diperchlorate, C₂₀H₁₂N₄S²⁺·2ClO₄^?, display bond alternation in the 2,1,3‐benzo­thia­diazo­le rings, which suggests their quinonoid character. The dipyridinium dication mol­ecules stack along the a axis and form a dimer with short S?N interheteroatom contacts [3.146 (4) Å] between the two 1,2,5‐thia­diazo­le rings. The dimer is surrounded by the perchlorate anions with which it forms a large number of intermolecular N—H?O and C—H?O hydrogen bonds.     

Analysis of the Interaction Between the C<Subscript>20</Subscript> Cage and <Emphasis Type="Italic">cis</Emphasis>-Ptcl<Subscript>2</Subscript>(NH<Subscript>3</Subscript>)<Subscript>2</Subscript>: A DFT Investigation of the Solvent Effect,Structures, Properties,and Topologies

This study investigates the interaction between C²⁰ and the cis-PtCl₂(NH₃)₂ complex using MPW1PW91 quantum chemical calculations in gas and solution phases. Two interaction modes between C²⁰ and the cis-PtCl₂(NH₃)₂ complex are considered: I-isomer (η₂-C²⁰) and II-isomer (η₁-C²⁰). It also determines the effects of the solvent polarity on the dipole moment, electronic spatial extent (ESE), structural parameters, and frontier orbital energies of two possible isomers of the C²⁰…cis-PtCl₂(NH₃)₂ complex. The bonding interaction between C²⁰ and the cis-PtCl₂(NH₃)₂ complex was examined through energy decomposition analysis (EDA). The metal–ligand bonds are evaluated using the percentage composition of the specific groups of frontier orbitals. The quantum theory of atoms in molecules (QTAIM) analysis is applied to assess the Pt–C bonds within the complex. Finally, the Pt–C spin-spin coupling constants are calculated using the gauge independent atomic orbital (GIAO) method.     

20‐Di­cyano­methyl­ene‐5,8,11,14‐tetraoxa‐2,17‐di­thia­bi­cyclo­[16.4.1]­tricosa‐1(23),18,21‐triene and its mercury(II) dichloride complex

The structures of the title compound, C₂₀H₂₄N₂O₄S₂, and its mercury(II) dichloride complex, dichloro{20‐di­cyano­methyl­ene‐5,8,11,14‐tetraoxa‐2,17‐di­thia­bi­cyclo­[16.4.1]­tricosa‐1(23),18,­21‐tri­ene‐κ⁴O,κS¹⁷}mercury(II), [HgCl₂(C₂₀­H₂₄­N₂­O₄­S₂)], have been determined by X‐ray crystallographic analyses. The mercury(II) dichloride complex has two independent mol­ecules of [HgCl₂(C₂₀H₂₄N₂O₄S₂)] in the lattice. The mercury(II) ion has pentagonal bipyramidal coordination which involves one S atom, four O atoms and two Cl^? ions.     

Synthesis of ecdysteroids with migrated group H<Subscript>3</Subscript>C<Superscript><Emphasis Type="Italic">18</Emphasis></Superscript>

Acid-catalyzed rearrangement of oxetane ring in oxetanoecdysteroids and their 7,8α-dihydroanalogs made it possible to synthesize ecdysteroids with H₃C¹⁸ group migrated from C¹³ to C¹⁴ atom.     

A three‐dimensional anionic metal–dicyanamide network in poly[ethyltriphenylphosphonium [tri‐μ2‐dicyanamidato‐cadmium(II)]]

The title compound, (C₂₀H₂₀P)[Cd(C₂N₃)₃], consists of ethyltriphenylphosphonium (EtPh₃P⁺) cations filling voids in a three‐dimensional anionic cadmium dicyanamide network. In the structure, each Cd^II atom is connected to six neighbouring Cd^II atoms through six separate dicyanamide ligands, forming cube‐shaped cages. The three‐dimensional anionic network encloses a solvent‐accessible void space of 1851 ų, amounting to 69.3% of the unit‐cell volume. Each cage accommodates only one EtPh₃P⁺ cation.     

Ethyl 6‐acetylamino‐6,7‐dihydro‐5H‐dibenzo[a,c]cycloheptene‐6‐carboxylate

The title compound, C₂₀H₂₁NO₃, is a derivative of Aib (α‐­aminoisobutyric acid) and is cyclized at the C^α position by bi­phenyl rings. The seven‐membered ring possesses C2 symmetry. The C^α cyclization causes the backbone to assume a helical conformation in the crystal structure. The packing of the mol­ecules is stabilized by intermolecular C—H?O, C—H?π and N—H?O hydrogen bonds.     

Additional insights from very‐high‐resolution 13C NMR spectra of long‐chain n‐alkanes

New information has been obtained from very‐high‐resolution ¹³C NMR studies of a series of long‐chain n‐alkanes. These compounds are fundamentally important in the petroleum industry and are essential to the life of some plants, flowers, and insects. At least partial resolution of the ten different ¹³C NMR signals of n‐C₂₀H₄₂ is observed at 11.7 T for solutions in C₆D₆ or C₆D₅CD₃. A ¹³C T₁ inversion‐recovery experiment provides much more detailed information than in previous studies of long‐chain n‐alkanes, demonstrates a steady increase in the relaxation times of the ten different carbons proceeding from the middle to the end of the chain because of segmental motion, and thus confirms the assignments for the interior carbons. In contrast, there is significant overlap for the signals for C‐7 and the more interior carbons in a solution of n‐C₁₆ or longer chain alkanes in CDCl₃. Not only are the chemical shifts sensitive to the solvent used, but also the relative chemical shifts change. Signals for the interior carbons of the odd‐number alkanes in CDCl₃ are better resolved than in the spectra of their even‐number counterparts. Some mixed aromatic solvent systems give increased dispersion of the cluster of C‐6 through C‐10 signals of n‐C₂₀H₄₂, n‐C₂₁H₄₄, and n‐C₂₂H₄₆. However, none of the solvents used could even partially resolve the C‐10 and C‐11 signals of n‐C₂₁H₄₄ or n‐C₂₂H₄₆ at 11.7 T, which may result from a different distribution of conformers for n‐C₂₁H₄₄ or n‐C₂₂H₄₆ than for n‐C₂₀H₄₂ and shorter n‐alkanes. Copyright © 2013 John Wiley & Sons, Ltd.     

Conversion of endohedral <Superscript>133</Superscript>Xe-fullerene to endohedral <Superscript>133</Superscript>Xe-fullerenol to be used in nuclear medicine

Summary Hydrophilic endohedral ¹³³Xe-fullerenols, [¹³³Xe@C₆₀(OH)_xand ¹³³Xe@C₇₀(OH)_x], were synthesized from hydrophobic endohedral ¹³³Xe-fullerenes. The yield of endohedral ¹³³Xe-fullerenols extracted in water was about 40% and 23% for C₆₀and C₇₀, respectively. The products stored in 0.9% NaCl solution at 20 °C were stable enough to be used in nuclear medicine.     

An organometallic RhIII complex with a distorted octahedral structure: (acetonitrile‐κN)dimethyl(1,4,7‐trimethyl‐1,4,7‐triazacyclononane‐κ3N,N′,N′′)rhodium(III) tetraphenylborate

In the title compound, [Rh(CH₃)₂(C₂H₃N)(C₉H₂₁N₃)](C₂₄H₂₀B), the geometry around the Rh^III centre is distorted octahedral, with elongated Rh—N bonds trans to the metal‐bonded methyl groups. The metal‐containing cations are located in channels formed by an anionic supramolecular mesh, in which aromatic π–π interactions between anionic [B(Ph)₄]^? units play a major role.     

Jahn–Teller Effect in Circulenes: X‐ray Diffraction Study of Coronene and Corannulene Radical Anions

Single‐crystal X‐ray diffraction studies of two polyaromatic radical anions crystallized as sodium salts, namely [Na(DME)₃]⁺[C₂₀H₁₀^?] ( 1 ) and [Na(DME)₃]⁺[C₂₄H₁₂^?] ( 2 ) are reported. This allowed the first structural evaluation of Jahn–Teller (JT) effects for monoreduced circulenes and a comparison between bowl‐shaped corannulene and planar coronene. The C_s and D_2h symmetrical distortions are found to fit the experimental data for C₂₀H₁₀^.? and C₂₄H₁₂^.?, respectively. The continuous symmetry measure (CSM) analysis was carried out to provide a quantitative measure of the JT distortions in 1 and 2 . In addition, the X‐ray crystallographic results were fully supported by DFT calculations.     

稳定的气相二价阴离子C7H22-

采用HF, MP2, CCSD以及CISD方法,研究了二价阴离子C₇H₂^2-和C₇H₃^2-及其一价阴离子的几何结构振动频率。在理论上,我们得到了C₇H₂^2-和C₇H₃^2-能量最低结构分别为：C₂C(H₂)C₄^2-和C₂CHCHCHC₂^2-,而且均没有虚频。计算这两种结构所有可能的碎片化通道,碎片化能表明这两结构都不易解离为两个一价阴离子碎片。但是这两结构的垂直电离能和绝热电离能表明C₂C(H₂)C₄^2-是稳定的,但C₂CHCHCHC₂^2-是不稳定的。     

Monoreduced 1,2‐dihydrocorannulene versus the parent corannulene

The monoanion of dihydrogenated corannulene isolated in the form of its potassium salt, namely tris(diglyme‐κ³O,O′,O′′)potassium hexacyclo[11.5.2.0^4,17.0^7,16.0^10,15.0^14,18]icosa‐1,3,5,7(16),8,10(15),11,13,17‐nonaenide, [K(C₆H₁₄O₃)₃](C₂₀H₁₂), has been structurally characterized for the first time. The X‐ray study confirms the previous NMR spectroscopic prediction that the two H atoms are attached to the same six‐membered ring to form 1,2‐dihydrocorannulene, thus destroying the aromaticity of only one arene ring of the corannulene core. The direct comparison of (C₂₀H₁₂)⁻ with the parent corannulene anion, (C₂₀H₁₀)⁻, is provided to illustrate the geometry perturbations caused by rim hydrogenation.     

Isomerization of silicenium and germenium ions in the systems C<Subscript>4</Subscript>H<Subscript>11</Subscript>M<Superscript>+</Superscript> (M = Si,Ge)

Equilibrium structures of the isomers and transition states of their interconversion in the system C₄H₁₁M⁺ (M = Si, Ge) have been obtained at theB3LYP level of theory using the cc-pVTZ basis set. The structures of these stationary points are close for Si and Ge; the most stable isomer in both systems is the tertiary cation (C₂H₅)(CH₃)₂M⁺, the second in energy is complex with ethylene [(CH₃)₂HM·C₂H₄]⁺. The secondary cation (C₂H₅)₂HM⁺ is third in energy isomer, the height of the barrier of interconversion for these three cations being practically independent on M. However, for M = Ge a substantial decrease in the energy of isomeric forms corresponding to complexes with alkanes is observed. As a result, in the system C₄H₁₁Ge⁺ the fourth in energy is isomer [(C₂H₅)Ge·C₂H₆]⁺ rather than [(C₂H₅)H₂Ge·C₂H₄]⁺ as for M = Si. Nevertheless, the height of the barriers for transition into these structures, although decreasing from M = Si to Ge, remain rather high, and the most favorable route of decomposition in both systems is the elimination of ethylene.     

Clamshell Opening in the Mixed‐Metal Supramolecular Aggregates Formed by Fourfold Reduced Corannulene for Maximizing Intercalated Metal Content

The first members of a new class of supramolecular organometallic compounds with mixed‐alkali‐metal cluster cores, LiK₅ and Li₃K₃, sandwiched between two four‐fold reduced corannulene decks are prepared and fully characterized. The triple‐decker supramolecular anions, [(C₂₀H₁₀^4?)(LiK₅)⁶⁺(C₂₀H₁₀^4?)]^2? and [(C₂₀H₁₀^4?)(Li₃K₃)⁶⁺(C₂₀H₁₀^4?)]^2?, illustrate a record ability of bowl‐shaped and highly charged corannulene to provide all its sites, five benzene rings fused to a central five‐membered ring, for binding of six alkali‐metal ions. The previously unseen engagement of the hub‐site of C₂₀H₁₀^4? in lithium binding is accompanied by unprecedented shifts up to ?24 ppm in ⁷Li NMR spectra. The discussion of product formation mechanism, augmented by calculations, is provided.     

3‐O‐Acetyl‐4‐deoxy‐4‐iodo‐β‐d‐fructo­furan­osyl 2,3,6‐tri‐O‐acetyl‐4‐chloro‐4‐deoxy‐α‐d‐gluco­pyran­oside

At 160 K, the gluco­pyran­osyl ring of the title compound, C₂₀H₂₈ClIO₁₃, has a near‐ideal ⁴C₁ conformation and the fructo­furan­osyl ring has a twist ⁴T₃ conformation. The two hydroxy groups are involved in intra‐ and intermolecular hydrogen bonds, with the latter interactions linking the mol­ecules into infinite one‐dimensional chains. The absolute configuration of the mol­ecule has been determined.     

Heptagon‐Embedded Pentacene: Synthesis,Structures, and Thin‐Film Transistors of Dibenzo[d,d′]benzo[1,2‐a:4,5‐a′]dicycloheptenes

This study presents a new class of conjugated polycyclic molecules that contain seven‐membered rings, detailing their synthesis, crystal structures and semiconductor properties. These molecules have a nearly flat C₆‐C₇‐C₆‐C₇‐C₆ polycyclic framework with a p‐quinodimethane core. With field‐effect mobilities of up to 0.76 cm² V^?1 s^?1 as measured from solution‐processed thin‐film transistors, these molecules are alternatives to the well‐studied pentacene analogues for applications in organic electronic devices.     

Heptagon‐Embedded Pentacene: Synthesis,Structures, and Thin‐Film Transistors of Dibenzo[d,d′]benzo[1,2‐a:4,5‐a′]dicycloheptenes

This study presents a new class of conjugated polycyclic molecules that contain seven‐membered rings, detailing their synthesis, crystal structures and semiconductor properties. These molecules have a nearly flat C₆‐C₇‐C₆‐C₇‐C₆ polycyclic framework with a p‐quinodimethane core. With field‐effect mobilities of up to 0.76 cm² V⁻¹ s⁻¹ as measured from solution‐processed thin‐film transistors, these molecules are alternatives to the well‐studied pentacene analogues for applications in organic electronic devices.     

Benzene Adsorption on C<Subscript>24</Subscript>, Si@C<Subscript>24</Subscript>, Si-Doped C<Subscript>24</Subscript>, and C<Subscript>20</Subscript> Fullerenes

The absorption feasibility of benzene molecule in the C₂₄, Si@C₂₄, Si-doped C₂₄, and C₂₀ fullerenes has been studied based on calculated electronic properties of these fullerenes using Density functional Theory (DFT). It is found that energy of benzene adsorption on C₂₄, Si@C₂₄, and Si-doped C₂₄ fullerenes were in range of –2.93 and –51.19 kJ/mol with little changes in their electronic structure. The results demonstrated that the C₂₄, Si@C₂₄, and Si-doped C₂₄ fullerenes cannot be employed as a chemical adsorbent or sensor for benzene. Silicon doping cannot significantly modify both the electronic properties and benzene adsorption energy of C₂₄ fullerene. On the other hand, C₂₀ fullerene exhibits a high sensitivity, so that the energy gap of the fullerene is changed almost 89.19% after the adsorption process. We concluded that the C₂₀ fullerene can be employed as a reliable material for benzene detection.     

Phase change in tetra­phenyl­phospho­nium perchlorate

The title compound, C₂₄H₂₀P⁺·ClO₄^?, undergoes a sudden reversible phase change in the region of 173–180 K which involves ordering of three quarters of the perchlorate anions.