Organic binary charge-transfer compounds of 2,2' : 6',2'' : 6'',6-trioxotriphenylamine and a pyrene-annulated azaacene as donors.

Three binary charge-transfer (CT) compounds resulting from the donor 2,2' : 6',2'' : 6'',6-trioxotriphenylamine (TOTA) and the acceptors FTCNQ and FBQ and of a pyrene-annulated azaacene (PAA) with the acceptor FTCNQ are reported. The identity of these CT compounds are confirmed by single-crystal X-ray diffraction as well as by IR, UV-vis-NIR and EPR spectroscopy. X-ray diffraction analysis reveals a 1 : 1 stoichiometry for TOTA·FTCNQ, a 2 : 1 donor : acceptor ratio in (TOTA)·FBQ, and a rare 4 : 1 stoichiometry in (PAA)·FTCNQ, respectively.

Reversible Multielectron Release from Redox-Active Three-Dimensional Molecular Barrels with Ruthenium-Alkenyl Moieties.

Three-dimensional molecular barrels and were synthesized in high yields from dinuclear ruthenium-vinyl clamps and tritopic triphenylamine-derived carboxylate linkers and characterized by multinuclear NMR spectroscopy including H-H COSY and H DOSY measurements, high-resolution electrospray ionization mass spectrometry, and X-ray crystallography. The metal frameworks of the cages adopt the shape of twisted trigonal prisms, and they crystallize as racemic mixtures of interdigitating Δ- and Λ-enantiomers with a tight columnar packing in . Electrochemical studies and redox titrations revealed that the cages are able to release up to 11 electrons on the voltammetric timescale and that their cage structures persist up to the hexacation level.

Electron-Rich Diruthenium Complexes with π-Extended Alkenyl Ligands and Their F TCNQ Charge-Transfer Salts.

The synthesis of dinuclear ruthenium alkenyl complexes with {Ru(CO)(P Pr ) (L)} entities (L=Cl in complexes Ru -3 and Ru -7; L=acetylacetonate (acac ) in complexes Ru -4 and Ru -8) and with π-conjugated 2,7-divinylphenanthrenediyl (Ru -3, Ru -4) or 5,8-divinylquinoxalinediyl (Ru -7, Ru -8) as bridging ligands are reported. The bridging ligands are laterally π-extended by anellating a pyrene (Ru -7, Ru -8) or a 6,7-benzoquinoxaline (Ru -3, Ru -4) π-perimeter. This was done with the hope that the open π-faces of the electron-rich complexes will foster association with planar electron acceptors via π-stacking.

C -Symmetric Assemblies from Trigonal Polycarbene Ligands and M Ions for the Synthesis of Three-Dimensional Polyimidazolium Cations.

Metallosupramolecular poly-NHC-metal assemblies were prepared from trigonal hexakis (H -1 a(PF ) and H -1 b(PF ) ) or nonakis (H -3(BF ) ) imidazolium salts and Ag O. Complexes [Ag (1 a) ](PF ) and [Ag (1 b) ](PF ) are built from six Ag ions sandwiched between two trigonal hexacarbene ligands with an inner and an outer NHC donor in each of the three ligand arms. The metal atoms are arranged in two triangles.

Synthesis, Characterization, and Properties of Tetraphenylethylene-Based Tetrakis-NHC Ligands and Their Metal Complexes.

The development of highly emissive dinuclear Ag or Au complexes [M L](PF ) (L=2 a, 2 b; M=Ag, Au) derived from tetraphenylethylene (TPE)-based tetrabenzimidazolin-2-ylidene ligands is reported. The new complexes exhibit a remarkable fluorescence enhancement compared to their parent benzimidazolium salts. The quantum yield (Φ ) value for salt H -2 a(PF ) in dilute solution (c=10  m) was found to be less than 1 %, whereas its metal complexes show Φ values up to 55 % at similar solution concentration.

On/off fluorescence emission induced by encapsulation, exchange and reversible encapsulation of a BODIPY-guest in self-assembled organometallic cages.

A dynamic guest-binding study of BODIPY-derivative 3 (3 = 1,3,5,7,8-pentamethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) with two Cp*Rh-based organometallic cages [Cp*Rh(μ-CA)(tpt)](OTf)1 (HCA = chloranilic acid, tpt = 2,4,6-tripyridyl-1,3,5-triazine) and [Cp*Rh(μ-DHNA)(tpt)](OTf)2 (HDHNA = 6,11-dihydroxynaphthacene-5,12-dione) have been demonstrated. While guest 3 displays a strong green fluorescence emission, the host-guest complexes 3⊂1 and 3⊂2 exhibit almost no emission. However, fluorescence emission can be again 'turned on' by adding coronene (4) or pyrene (5) into the solution of 3⊂1 and 3⊂2.

Synthesis, Characterization, and Properties of Organometallic Molecular Cylinders Bearing Bulky Imidazo[1,5-a]pyridine-Based N-Heterocyclic Carbene Ligands.

The metal-controlled self-assembly of organometallic molecular cylinders from a series of imidazo[1,5-a]pyridine-based tris-NHC ligands is described in this report. The imidazo[1,5-a]pyridinium salts H -L(PF ) (L=4 a-4 c) were treated with 1.5 equivalents of Ag O to yield the trinuclear Ag hexacarbene cages [Ag (L) ](PF ) (L=4 a-4 c), in which three Ag are sandwiched between the two tricarbene ligands.

Oxidative addition of 2-halogenoazoles-direct synthesis of palladium(II) complexes bearing protic NH,NH-functionalized NHC ligands.

The chemistry of N-heterocyclic carbenes (NHCs) is dominated by N,N'-dialkylated or -diarylated derivatives. Such NHC ligands are normally obtained by C2-deprotonation of azolium cations or by reductive elimination from azol-2-thiones. A simple one-step procedure is described that leads to complexes with NH,NH-functionalized NHC ligands by the oxidative addition of 2-halogenoazoles to complexes of zero-valent transition metals.