Synthesis and Characterization of Platinum(II) Complexes with Bis(3-(trifluoromethyl)-pyrazolyl)-borate Auxiliary Ligands.

Five novel square-planar platinum(II) complexes with electron-deficient bis(3-(trifluoromethyl)-pyrazolyl)-borate auxiliary ligands were synthesized in yields ranging from 31% to 76%. The complexes feature cyclometalating C^C*-ligands based on phenyl imidazopyridines with different substituents (H, 3-Me, 4-Me, 4-EtO, and 4-CFO). All five complexes emit light in the green-blue region with photoluminescence quantum yields between 32% and 56% (2 wt % in PMMA).

Synthesis and physical properties of tunable aryl alkyl ionic liquids based on 1-aryl-4,5-dimethylimidazolium cations.

We present a new class of tunable aryl alkyl ionic liquids (TAAILs) based on 1-aryl-4,5-dimethylimidazolium cations with electron-withdrawing and -donating substituents in different positions of the phenyl ring and the bis(trifluoromethylsulfonyl)imide (NTf) anion. We investigated the effect of additional methyl groups in the backbone of the imidazolium core on the physical properties regarding viscosity, conductivity and electrochemical window. With an electrochemical window of up to 6.

Synthesis and characterization of Pt(II) and Au(I) complexes with -oxy-heterocyclic carbene ligands (NOHCs).

Two -alkyloxy-'-phenylimidazolium proligands and the corresponding platinum(II) cyclometalated -alkyloxyimidazol-2-ylidene complexes with β-diketonate auxiliary ligands, [(C^C*)Pt(L∩L)] (L∩L = acetyacetonate (acac) or 1,3-bis(2,4,6-trimethylphenyl)-propane-1,3-dionato (mesacac)) were synthesized and fully characterized. In addition, a Au(I) monocarbene complex was synthesized, isolated and characterized. Solid-state structures of two cyclometalated platinum(II) NOHC complexes and the Au(I) NOHC complex were obtained providing structural proof.

Phosphorescent Platinum(II) Complexes with a Spiro-fused Xanthene Unit: Synthesis and Photophysical Properties.

Novel platinum(II) complexes, derived from the spiro[fluorene-9,9'-xanthene] (SFX) motif, were synthesized and combined with different auxiliary ligands such as acetylacetonate (acac), bis(2,4,6-trimethylphenyl)propane-1,3-dionate (mesacac) and dihydrobis(3,5-dimethylpyrazole-1-yl) borate. The final products were obtained in yields of up to 36 % and characterized by NMR, X-ray and combustion analysis. These complexes have structured green-blue emission spectra with Commission Internationale de l'Éclairage (CIE) coordinates of (0.

Synthesis and Photophysical Properties of Monometallic C^C* Platinum(II) Formamidinate Complexes using Sterically Demanding Ligands.

A novel class of cyclometalated platinum(II) complexes-previously considered to be inaccessible-was synthesized by an improved synthetic route utilizing ligands predicted by density functional theory calculations. Based on a concise quantum chemical screening three model ligands with varying steric demand were chosen and a series of six photoluminescent C^C* cyclometalated platinum(II) formamidinate complexes was obtained. The least sterically demanding ligand led to a bimetallic complex in two isomeric forms, which could be separated and confirmed by the corresponding solid-state structures.

Friedel-Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs).

An iron(III) chloride hexahydrate-catalyzed Friedel-Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs) has been developed. Through optimization of the metal salt, reaction conditions and ionic liquids, we were able to design a robust catalyst system that tolerates different electron-rich substrates under ambient atmosphere and allows for a multigram scale.

Tunable Aryl Alkyl Ionic Liquid Supported Synthesis of Platinum Nanoparticles and Their Catalytic Activity in the Hydrogen Evolution Reaction and in Hydrosilylation.

Tunable aryl alkyl ionic liquids (TAAILs) are ionic liquids (ILs) with a 1-aryl-3-alkylimidazolium cation having differently substituted aryl groups. Herein, nine TAAILs with the bis(trifluoromethylsulfonyl)imide anion are utilized in combination with and without ethylene glycol (EG) as reaction media for the rapid microwave synthesis of platinum nanoparticles (Pt-NPs). TAAILs allow the synthesis of small NPs and are efficient solvents for microwave absorption.

Electronic Structure and Magnetic Properties of a High-Spin Mn Complex: [Mn(mesacac) ] (mesacac=1,3-Bis(2,4,6-trimethylphenyl)-propane-1,3-dionato).

Metal acetylacetonates of the general formula [M(acac) ] (M =Cr, Mn, Fe, Co) are among the best investigated coordination compounds. Many of these first-row transition metal complexes are known to have unique electronic properties. Independently, photophysical research with different β-diketonate ligands pointed towards the possibility of a special effect of the 2,4,6-trimethylphenyl substituted acetylacetonate (mesacac) on the electron distribution between ligand and metal (MLCT).

Synthesis and Physical Properties of Tunable Aryl Alkyl Ionic Liquids (TAAILs) Comprising Imidazolium Cations Blocked with Methyl-, Propyl- and Phenyl-Groups at the C2 Position.

Imidazolium-based ionic liquids are very popular for different applications because of their low viscosity and melting point. However, the hydrogen atom at the C2 position of the imidazolium cation can easily be deprotonated by a base, resulting in a reactive carbene. If an inert ionic liquid is needed, it is necessary to introduce an unreactive alkyl or aryl group at the C2 position to prevent deprotonation.

Phosphorescent Bimetallic C^C* Platinum(ii) Complexes with Bridging Substituted Diphenylformamidinates.

A series of phosphorescent bimetallic platinum(II) complexes is presented, which were synthesized by the combination of bidentate cyclometalated N-heterocyclic carbene ligands and different bridging diphenylformamidinates. The complexes were characterized by standard techniques and additionally two solid-state structures could be obtained. Photoluminescence measurements revealed the strong emissive behavior of the compounds with quantum yields of up to 90 % and emission lifetimes of approx.

Cyclometalated Spirobifluorene Imidazolylidene Platinum(II) Complexes with Predominant LC Emissive Character and High Photoluminescence Quantum Yields.

Two novel bidentate C^C* cyclometalated platinum(II) complexes comprising a spiro-conjugated bifluorene ligand and different β-diketonate auxiliary ligands are synthesized and characterized. Their preparation employs a robust and elaborate synthetic protocol commencing with an -heterocyclic carbene precursor. Structural characterization by means of NMR techniques and solid-state structures validate the proposed and herein presented molecular scaffolds.

Microswimming by oxidation of dibenzylamine.

Chemiophoretic nano- and micromotors require a constant flow of product molecules to maintain a gradient that enables their propulsion. Apart from a smaller number of redox reactions that have been used, catalytic reactions are the main source of energy with the obvious benefit of making on-board fuel storage obsolete. However, the decomposition of HO seems to strongly dominate the literature and although motion in HO through water splitting is becoming more popular, so far only a few different reactions have been used for propulsion of photocatalytic microswimmers.

The Facile Deposition of Pt Nanoparticles on Reduced Graphite Oxide in Tunable Aryl Alkyl Ionic Liquids for ORR Catalysts.

In this study, we present the facile formation of platinum nanoparticles (Pt-NPs) on reduced graphite oxide (rGO) (Pt-NP@rGO) by microwave-induced heating of the organometallic precursor ((MeCp)PtMe in different tunable aryl alkyl ionic liquids (TAAIL). In the absence of rGO, transmission electron microscopy (TEM) reveals the formation of dense aggregates of Pt-NPs, with primary particle sizes of 2 to 6 nm. In contrast, in the Pt-NP@rGO samples, Pt-NPs are homogeneously distributed on the rGO, without any aggregation.

Synthesis and Physical Properties of Tunable Aryl Alkyl Ionic Liquids (TAAILs).

Tunable aryl alkyl ionic liquids (TAAILs) based on the imidazolium cation were first reported in 2009. Since then, a series of TAAILs with different properties due to the electron-donating or -withdrawing effect of the substituents at the aryl ring has been developed. Herein, a wide variety of those ionic liquids (ILs) is presented in terms of their cation structure.

Polymorphic Phosphorescence from Separable Aggregates with Unique Photophysical Properties.

Platinum complexes aggregate into polymorphs with different intermolecular interactions leading to different photophysical properties. Strong intermolecular interactions stabilize the aggregate to such an extent that the polymorphs can be separated directly by column chromatography. Solid-state structures as well as quantum-chemical calculations confirmed the effect of the interactions on the photophysical properties.

Tetrakis(pentafluoroethyl)gallate, [Ga(C F ) ] , Ionic Liquids.

We synthesized new imidazolium-based tunable aryl alkyl ionic liquids (TAAILs) with the weakly coordinating tetrakis(pentafluoroethyl)gallate anion, [Ga(C F ) ] . Phenyl and phenyl derivatives (2-Me, 4-OMe, 2,4-F) were combined with varying alkyl chain lengths at the imidazolium core leading to TAAILs, which were investigated with regard to their viscosity, conductivity, and electrochemical window and compared to EMIM and BMIM standard cations. Remarkable low viscosities of 29 cP at 25 °C for [BMIM][Ga(C F ) ] were achieved.

Type-II Clathrate Na Ge from a Redox-Preparation Route.

The metastable type-II clathrate Na Ge was obtained from Na Ge by applying a two-step procedure. At first, Na Ge was reacted at 70 °C with a solution of benzophenone in the ionic liquid (IL) 1,3-dibutyl-2-methylimidazolium-bis(trifluoromethylsulfonyl) azanide. The IL was inert towards Na Ge , but capable of dissolving the sodium salts formed in the redox reaction.

C^C* Platinum(II) Complexes with Electron-Withdrawing Groups and Beneficial Auxiliary Ligands: Efficient Blue Phosphorescent Emission.

The combination of strong electron-withdrawing groups in cyclometalated N-heterocyclic carbene ligands (C^C*) with known beneficial auxiliary ligands in phosphorescent platinum(II) complexes leads to efficient light-to-deep-blue emission with quantum yields of up to 92%. All compounds were characterized and investigated regarding their photophysical, electrochemical, and thermal properties, and three complexes could additionally be characterized by solid-state structures. Density functional theory calculations (PBE0/6-311G* with dispersion correction) are reported.

Reactivity and Controlled Redox Reactions of Salt-like Intermetallic Compounds in Imidazolium-Based Ionic Liquids.

Substituted imidazolium ionic liquids (ILs) were investigated for their reactivity towards Na Ge as a model system containing redox-sensitive Zintl cluster anions. The ILs proved widely inert for imidazolium cations with a 1,2,3-trisubstitution at least by alkyl groups, and for the anion bis(trifluoromethylsulfonyl)azanide (TFSI). A minute conversion of Na Ge observed on long-time contact with such ILs was not caused by dissolution of the salt-like compound, and did thus not provide dissolved Ge clusters.

Platinum(II) Complexes with Bis(pyrazolyl)borate Ligands: Increased Molecular Rigidity for Bidentate Ligand Systems.

The structural motif of platinum(II) complexes bearing cyclometalating N-heterocyclic carbene ligands can be used to design deep-blue phosphors for application in organic light-emitting diodes. However, the photophysical properties of the resulting molecules are also highly dependent on the auxiliary ligand. These often allow molecular deformations in the excited state which contribute to non-radiative decay processes that diminish the attainable quantum yield.

Expanding the Electrochemical Window: New Tunable Aryl Alkyl Ionic Liquids (TAAILs) with Dicyanamide Anions.

A set of new tunable aryl alkyl ionic liquids (TAAILs) based on the 1-aryl-3-alkyl imidazolium motif has been synthesized, in which the following variables were systematically changed: alkyl chain length, aryl substitution (group and position), and counter ion. TAAILs with dicyanamide (DCA) and bis(trifluoromethylsulfonyl)imide (N(SO CF ) , NTf ) anions showed remarkable differences of their physical properties: NTf ionic liquids were found to have high decomposition temperatures and viscosities well below those of the DCA TAAILs. In contrast, the dicyanamide anion increased the electrochemical stability leading to TAAILs with an extremely wide electrochemical window of up to 7.

Sky-Blue Triplet Emitters with Cyclometalated Imidazopyrazine-Based NHC-Ligands and Aromatic Bulky Acetylacetonates.

Platinum(II) complexes with an N-heterocyclic carbene and a cyclometalating phenyl ligand (C^C*) are excellent candidates as efficient blue triplet emitters for OLED applications. The electronic and photophysical properties of these complexes can be fine-tuned with the objective to increase the quantum yields and lower the phosphorescence decay times. We found that platinum complexes with an imidazopyrazine C^C* ligand and bulky acetylacetonates are sky-blue triplet emitters, characterised by an almost unitary quantum yield and short phosphorescence decay times.

The addition of Grignard reagents to carbodiimides. The synthesis, structure and potential utilization of magnesium amidinates.

Direct synthesis of magnesium amidinates of the general formula [RNC(R1)NR]MgR2 has been performed from appropriate carbodimide and Grignard reagents (R = iPr, Cy, pTol; R1 = Me, nBu; R2 = nBu, Cl, I). Magnesium bisamidinates of the composition [RNC(R1)NR]2Mg(solvent)2 are accessible from [RNC(R1)NR]MgR2 and via the Schlenk-like equilibrium in coordinating solvents. The only isolated amidinatomagnesium halide, preserved in the dinuclear form of {[pTolNC(Me)N-pTol]Mg(THF)}2-μ-(THF)-μ-(Cl)2, has been obtained from the reaction of pTol-N[double bond, length as m-dash]C[double bond, length as m-dash]N-pTol with MeMgCl(THF)n in hexane.

Aggregation control of Ru and Ir nanoparticles by tunable aryl alkyl imidazolium ionic liquids.

Metal-nanoparticles (M-NPs) were synthesized in a wet-chemical synthesis route in tunable aryl alkyl ionic liquids (TAAILs) based on the 1-aryl-3-alkyl-substituted imidazolium motif from Ru(CO) and Ir(CO) by microwave-heating induced thermal decomposition. The size and size dispersion of the NPs were determined by transmission electron microscopy (TEM) to an average diameter of 2.2(±0.