Bottom-up Synthesis and Characterization of Porous 12-Atom-Wide Armchair Graphene Nanoribbons.

Although several porous carbon/graphene nanoribbons (GNRs) have been prepared, a direct comparison of the electronic properties between a nonporous GNR and its periodically perforated counterpart is still missing. Here, we report the synthesis of porous 12-atom-wide armchair-edged GNRs from a bromoarene precursor on a Au(111) surface via hierarchical Ullmann and dehydrogenative coupling. The selective formation of porous 12-GNRs was achieved through thermodynamic and kinetic reaction control combined with tailored precursor design.

Dihydroguaiazulenide Complexes and Catalysts of Group 8-12 Transition Metals: Ligands from Renewable Feedstock Replace, even Outmatch Petrochemical Based Cyclopentadienyl Chemistry.

We present an in-depth study of the sterically demanding Cp-synthon (8-H-GuaH)Li isolated from natural product guaiazulene (Gua) as a ligand transfer reagent towards late transition metal complex precursors. The synthesis and full characterization of selected, essentially unexplored homo- and heteroleptic 8-H-guaiazulenide complexes of iron, ruthenium, cobalt, rhodium, platinum, copper and zinc are discussed in detail. In order to demonstrate their potential in catalytic applications, [(GuaH)PtMe ] was selected.

Heavy silylchalcogenido lanthanates synthesis PhP[CpLa-ESiMe] (E = S, Se, and Te) fluoride-induced demethylation of dimethylcarbonate to PhP[OCOMe] key intermediate.

We report a new high-yield synthesis of so far not accessible tetraphenylphosphonium methylcarbonate PhP[OCOMe] solvothermal fluoride-induced demethylation and MeF elimination at MeCO (DMC) by PhP-F, structurally characterized as λ-fluorophosphoran by XRD. The synthetic value of PhP[OCOMe] key compound for preparing nearly all kinds of other PhP[anion] salts with perfectly crystallizing (not symmetry frustrated) cation is demonstrated by examples beyond ionic liquid research: a complete set of silylchalcogenide salts PhP[ESiMe] (E = S, Se, and Te) including the first example of a structurally characterized non-coordinating, naked [Te-SiMe] anion is presented. With this set of soft Lewis bases and metal organic Lewis acids [CpLa] at hand, a comprehensive series of crystalline 1 : 1 lanthanate complexes PhP[CpLa-ESiMe] has been prepared.

Rylene- and diaza-rylene-derived cobalt clusters for solid-state pyrolysis towards undoped and N-doped carbon nanoparticles.

2,7-Diazapyrene and 2,9-diazaperopyrene tetraalkynes (12 and 13) as well as related non-N-doped pyrene and peropyrene tetraalkynes (14 and 15) of the same shape were used as polyaromatic templates in their metalation by [Co(CO)]. Isolated cobalt-rich [(12, 13, 14, 15)Co(CO)] clusters were characterized by means of NMR, IR, UV-Vis spectroscopy and X-ray crystallography. Their thermogravimetric behaviour and products of solid-state pyrolysis (SSP) were investigated by TGA, DSC, and scanning electron microscopy (SEM).

Tetrasubstituted Peropyrenes Formed by Reductive Aromatization: Synthesis, Functionalization and Characterization.

The chromophore class of 1,3,8,10-tetrasubstituted peropyrenes was effectively synthesized from peropyrenequinone via a Zn-mediated reductive aromatization approach. In one step, a symmetric functionalization of the peropyrene backbone introducing silylethers (2,3), pivaloyl (4), triflyl (5) and also phosphinite (6) groups was established. Furthermore, the potential of using 4 and 5 in transition metal catalysed cross couplings was explored leading to 1,3,8,10-tetraaryl (8-11) and tetraalkynyl (7) peropyrenes.

Highly Selective Ortho-Directed Dicarboxylation of Cyclopentadiene by Methylcarbonates and CO or COS - First Insight into Co-ordination Chemistry of New Ambident Ligands.

This research presents the highly regioselective syntheses of 1,2-dicarboxylated cyclopentadienide salts [Cat] [C H (CO ) H] by reaction of a variety of organic cation methylcarbonate salts [Cat]OCO Me (Cat=NR , PR , Im ) with cyclopentadiene (CpH) or by simply reacting organic cation cyclopentadienides Cat[Cp] (Cat=NR , PR , Im ) with CO . One characteristic feature of these dianionic ligands is the acidic proton delocalized in an intramolecular hydrogen bridge (IHB) between the two carboxyl groups, as studied by H NMR spectroscopy and XRD analyses. The reaction cannot be stopped after the first carboxylation.

Access to Functionalized Pyrenes, Peropyrenes, Terropyrenes, and Quarterropyrenes via Reductive Aromatization.

Herein we report a versatile concept for the synthesis of fourfold functionalized, soluble pyrenes, peropyrenes, terropyrenes, and quarterropyrenes. They were obtained by a modular stepwise approach towards the rylene scaffold via Suzuki-Miyaura cross coupling, oxidative cyclodehydrogenation in the presence of caesium hydroxide under air, and finally zinc-mediated reductive silylation. The silylated reaction products were characterized by X-ray crystallography.

Chalcogenido-Dimethylgallates and -Indates DMPyr [Me M(μ -E)] (M=Ga, In; E=S, Se): Building Blocks for Higher and Lower Order Chalcogenidoindates.

Metalation of the anions in the ionic liquids DMPyr[SH] and DMPyr[SeH] (DMPyr=1,1-dimethylpyrrolidinium) by trimethylgallium and trimethylindium is investigated. The reaction proceeds via pre-coordination of [EH] , methane elimination and formation of an unprecedented series of chalcogenido metalates DMPyr [Me M(μ -E)] (M=Ga, In; E=S, Se). These show the presences of dinuclear dianions with four-membered ring structures displaying highly nucleophilic bridging chalcogenide ligands in their crystallographically determined molecular structures.

A Series of Homoleptic Linear Trimethylsilylchalcogenido Cuprates, Argentates and Aurates Cat[MeSiE-M-ESiMe] (M = Cu, Ag, Au; E = S, Se).

The syntheses and XRD molecular structures of a complete series of silylsulfido metalates Cat[M(SSiMe)] (M = Cu, Ag, Au) and corresponding silylselenido metalates Cat[M(SeSiMe)] (M = Cu, Ag, Au) comprising lattice stabilizing organic cations (Cat = PhP or PPN) are reported. Much to our surprise these homoleptic cuprates, argentates, and aurates are stable enough to be isolated even in the absence of any strongly binding phosphines or N-heterocyclic carbenes as coligands. Their metal atoms are coordinated by two silylchalcogenido ligands in a linear fashion.

Kekulene: On-Surface Synthesis, Orbital Structure, and Aromatic Stabilization.

We revisit the question of kekulene's aromaticity by focusing on the electronic structure of its frontier orbitals as determined by angle-resolved photoemission spectroscopy. To this end, we have developed a specially designed precursor, 1,4,7(2,7)-triphenanthrenacyclononaphane-2,5,8-triene, which allows us to prepare sufficient quantities of kekulene of high purity directly on a Cu(111) surface, as confirmed by scanning tunneling microscopy. Supported by density functional calculations, we determine the orbital structure of kekulene's highest occupied molecular orbital by photoemission tomography.

Homoleptic trimethylsilylchalcogenolato zincates [Zn(ESiMe)] and stannanides [Sn(ESiMe)] (E = S, Se): precursors in solution-based low-temperature binary metal chalcogenide and CuZnSnS (CZTS) synthesis.

Organic cation salts with homoleptic zincate and stannanide anions, Ph4P [Zn(ESiMe3)3] (E = S (1a), Se (1b)) and Cat [Sn(ESiMe3)3] (Cat = Ph4P+ (E = S (2a-Ph4P); Cat = PPN+ (E = S 2a-Ph4P, Se (2a)) are presented and structurally characterized. Efforts to isolate neutral thermally metastable stannane precursors [Sn(ESiMe3)4] (E = S (3), Se(4)) are reported as well. The thermal decomposition of the presented precursors to yield binary sulfides and selenides of zinc and tin is investigated.

On-Surface Synthesis and Characterization of a Cycloarene: C108 Graphene Ring.

The synthesis of cycloarenes in solution is challenging because of their low solubility and the often hindered cyclodehydrogenation reaction of their nonplanar precursors. Using an alternative on-surface synthesis protocol, we achieved an unprecedented double-stranded hexagonal cycloarene containing 108 sp carbon atoms. Its synthesis is based on hierarchical Ullmann coupling and cyclodehydrogenation of a specially designed precursor on a Au(111) surface.

Ferrocenyl-sulfonium ionic liquids - synthesis, characterization and electrochemistry.

New ferrocenylsulfonium cation based ionic liquids were prepared by direct alkylation of the corresponding ferrocenyl-based thioethers with N-alkylbis(trifluoromethanesulfonyl)imides (R'TFSI). This convenient direct access to organometallic sulfonium bis(trifluoromethanesulfonyl)imide (TFSI) salts without the need for ion exchange was chosen in order to obtain highly pure and reversibly redox active room temperature ILs in many cases. In other cases the anion cation interaction in the solid state was studied by XRD analyses.

Synthesis of Adjacent Quaternary Stereocenters by Catalytic Asymmetric Allylboration.

Allylboration of ketones with γ-disubstituted allylboronic acids is performed in the presence of chiral BINOL derivatives. The reaction is suitable for single-step creation of adjacent quaternary stereocenters with high selectivity. We show that, with an appropriate choice of the chiral catalyst and the stereoisomeric prenyl substrate, full control of the stereo- and enantioselectivity is possible in the reaction.