Coinage Metal Complexes of a Sterically Encumbered Anionic Pyridylborate.

Sterically loaded, anionic pyridine has been synthesized and utilized successfully in the stabilization of a isoleptic series of coinage metal complexes. The treatment of [4-(PhB)-2,6-TripPy]K (Trip=2,4,6-PrCH) with CuBr(PPh), AgCl(PPh) or AuCl(PPh) (Py=pyridine) afforded the corresponding [4-(PhB)-2,6-TripPy]M(PPh) (M=Au, Ag, Cu) complexes, via salt metathesis, as isolable, crystalline solids. Notably, these reactions avoid the facile single electron transfer chemistry reported with the less bulky ligand systems.

studies of reversible solid-gas reactions of ethylene responsive silver pyrazolates.

Solid-gas reactions and powder X-ray diffraction investigations of trinuclear silver complexes {[3,4,5-(CF)Pz]Ag} and {[4-Br-3,5-(CF)Pz]Ag} supported by highly fluorinated pyrazolates reveal that they undergo intricate ethylene-triggered structural transformations in the solid-state producing dinuclear silver-ethylene adducts. Despite the complexity, the chemistry is reversible producing precursor trimers with the loss of ethylene. Less reactive {[3,5-(CF)Pz]Ag} under ethylene pressure and low-temperature conditions stops at an unusual silver-ethylene complex in the trinuclear state, which could serve as a model for intermediates likely present in more common trimer-dimer reorganizations described above.

Classical Gold Carbonyl Complexes in Tetrahedral and Trigonal-Planar Settings.

A unique four-coordinate, classical gold(I)-carbonyl complex with substantial backdonation from gold has been isolated by using a B-methylated and fluorinated tris(pyridyl)borate chelator. Its lighter silver(I) and copper(I) analogs enabled a study of trends in the coinage-metal family. The B-arylated ligand version also afforded a gold-carbon monoxide complex that displays a notably low C-O stretch value, but with trigonal planar geometry at the gold.

Thallium(I) Complexes of Tris(pyridyl)borates and a Comparison to Their Pyrazolyl Analogues.

Thallium(I) complexes of B-methylated and B-phenylated tris(pyridyl)borates featuring trifluoromethyl groups at the pyridyl ring 6-positions have been synthesized by metathesis using the corresponding potassium salts [MeB(6-(CF)Py)]K and [PhB(6-(CF)Py)]K with thallium(I) acetate. The closely related tris(pyrazolyl)borate analogue [PhB(3-(CF)Pz)]Tl has also been prepared, and comparisons of structural and spectroscopic features between the two scorpionate families are presented. [MeB(6-(CF)Py)]Tl displays κ-coordination of the tris(pyridyl)borate similar to that of tris(pyrazolyl)borate in [MeB(3-(CF)Pz)]Tl, while [PhB(6-(CF)Py)]Tl and [PhB(3-(CF)Pz)]Tl feature κ-, ligand coordination modes with the B-phenyl groups flanking the thallium sites.

Filling the gap with a bulky diaryl boron group: fluorinated and non-fluorinated copper pyrazolates fitted with a dimesityl boron moiety on the backbone.

Successful synthesis has been reported of 4-MesB-3,5-(CF)PzH and 4-MesB-3,5-(CF)PzH bearing sterically demanding diarylboron moieties at the pyrazole ring 4-position, and their corresponding copper(I) pyrazolate complexes. They show visible blue photoluminescence in solution. The X-ray crystal structures revealed that the fluorinated {[4-BMes-3,5-(CF)Pz]Cu} crystallizes as discrete trinuclear molecules whereas as the non-fluorinated {[4-BMes-3,5-(CH)Pz]Cu} forms dimers of trimers with two close inter-trimer Cu⋯Cu separations.

Copper(I), Silver(I), and Gold(I) Ethylene Complexes of Fluorinated and Boron-Methylated Bis- and Tris(pyridyl)borate Chelators.

Bis- and tris-pyridyl borate ligands containing pyridyl donor arms, a methylated boron cap, and a fluorine-lined coordination pocket have been prepared and utilized in coinage metal chemistry. The tris(pyridyl)borate ligand has been synthesized using a convenient boron source, [NBu][MeBF]. These N-based ligands permitted the isolation of group 11 metal-ethylene complexes [MeB(6-(CF)Py)]M(CH) and [MeB(6-(CF)Py)]M(CH) (M = Cu, Ag, Au).

Relativistic modulation of supramolecular halogen/copper interactions and phosphorescence in Cu(I) pyrazolate cyclotrimers.

Described herein are the synthesis, structure, and photophysics of the iodo-substituted cyclic trinuclear copper(I) complex, Cu[4-I-3,5-(CF)Pz] supported by a highly-fluorinated pyrazolate in comparison with its previously reported 4-Br/4-Cl analogues. The crystal structure is stabilised by multiple supramolecular interactions of Cu⋯I and hydrogen/halogen bonding. The photophysical properties and supramolecular interactions are investigated experimentally/computationally for all three 4-halo complexes relativistic effects.

Synthesis, Photophysical, Electrochemical, and Non-linear Optical Properties of Triaryl Pyrazole-based B-N Coordinated Boron Compounds.

We report here a set of triaryl pyrazole based B-N coordinated boron compounds (11-17) synthesized by electrophilic aromatic borylation strategy. All the pyrazole boron compounds were thoroughly characterized using multinuclear NMR spectroscopy, LC-MS, and single crystal X-ray diffraction analysis (for 12-17). The photoluminescence measurements of 11-17 revealed that the emission peak maxima were tuned based on the substitution on N-phenyl.

Fluorinated tris(pyridyl)borate ligand support on coinage metals.

A useful ligand involving three pyridyl donor arms and fluorocarbon substituents surrounding the coordination pocket has been assembled and utilized in coinage metal chemistry. This tris(pyridyl)borate serves as an excellent ligand support for the stabilization of ethylene complexes of copper, silver and gold.

Linear Extension of Anthracene via B←N Lewis Pair Formation: Effects on Optoelectronic Properties and Singlet O Sensitization.

The functionalization of polycyclic aromatic hydrocarbons (PAHs) via B←N Lewis pair formation offers an opportunity to judiciously fine-tune the structural features and optoelectronic properties, to suit the demands of applications in organic electronic devices, bioimaging, and as sensitizers for singlet oxygen generation. We demonstrate that the N-directed electrophilic borylation of 2,6-di(pyrid-2-yl)anthracene offers access to linearly extended acene derivatives Py-BR (R=Et, Ph, C F ). In comparison to indeno-fused 9,10-diphenylanthracene, the formal "BN for CC" replacement in Py-BR selectively lowers the LUMO, resulting in a much reduced HOMO-LUMO gap.

Synthesis of pyrazole anchored three-coordinated organoboranes and their application in the detection of picric acid.

Three-coordinated organoboron fluorophores bearing 3,5-diphenyl pyrazoles have been synthesized. The pyrazole anchored boron fluorophores show selective fluorescence quenching response to trinitrophenol (or) picric acid (PA) and have the ability to discriminate picric acid over other analytes. We investigated nonlinear optical (NLO) properties of these three-coordinated organoboron compounds (in solutions) in the presence and absence of PA.

Synthesis of π-extended B ← N coordinated phenanthroimidazole dimers and their linear and nonlinear optical properties.

Intramolecular B ← N coordinated fluorophores have shown potential applications in optoelectronics and as sensors due to their unique photophysical properties. In this work, we report the synthesis and characterization of π-conjugated boron doped phenanthroimidazole dimers. All the π-conjugated B ← N coordinated phenanthroimidazole dimers exhibited high quantum yields in solution (up to 99%) and moderate quantum yields in the solid state (up to 51%).

Controlling the Optoelectronic Properties of Pyrene by Regioselective Lewis Base-Directed Electrophilic Aromatic Borylation.

Given that pyrene represents one of the most versatile chromophores, the development of new selective routes for its functionalization and tuning of its emission properties is highly desirable. Pyrene-based BN Lewis pair (LP)-functionalized polycyclic aromatic hydrocarbons (PAHs) were prepared by regioselective Lewis base-directed electrophilic aromatic substitution. The requisite 1,6-dipyridylpyrene ligands were accessed by Suzuki-Miyaura cross-coupling of 1,6-bis(pinacolatoboryl)pyrenes with 2-bromopyridine derivatives.

Carbatriphyrin(3.1.1)-A Distinct Coordination Approach of B to Generate Organoborane and Weak C-H⋅⋅⋅B Interactions.

Carbatriphyrin(3.1.1) is the structural isomer of biphenylcorrole and achieved by switching the bonding mode of biphenyl unit from 3,3' to 2,3' which turns the corrole into a triphyrin analogue.

Tetracoordinate Imidazole-Based Boron Complexes for the Selective Detection of Picric Acid.

N,N-Dimethylamine and N,N-diphenylamine-decorated highly fluorescent imidazole borates have been synthesized and investigated as new fluorophores for the selective detection of trinitrophenol/picric acid (PA). Structural studies of a probe 1 and PA (1·PA) complex revealed that the adduct formed by the deprotonation of PA by the -NMe group along with weak interactions is responsible for the selective detection of PA over other polynitrated organic compounds.

Design, synthesis, photophysical and electrochemical properties of 2-(4,5-diphenyl-1-p-aryl-1H-imidazol-2-yl)phenol-based boron complexes.

New hybrid organic-inorganic boron compounds using an imidazole core have been readily synthesized by a two-step procedure from commercially available simple starting materials. All boron compounds were fully characterized by multinuclear NMR spectroscopy, LC-MS, thermogravimetric analysis, cyclic voltammetry and single crystal X-ray diffraction analysis (for & ). The photoluminescence measurements of revealed distinct emission peak maxima located at 378, 379 and 387 nm, respectively.

Synthesis of a cyclometalated 1,3,5-triphenylpyrazole palladium dimer and its activity towards cross coupling reactions.

A phosphine free 1,3,5-triphenylpyrazole acetate-bridged palladacycle was prepared from simple commercially available starting materials. The activity of the palladacycle in the Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions was evaluated. The palladacycle precatalyst shows a wide substrate scope, both in Mizoroki-Heck as well as in Suzuki-Miyaura cross-coupling reactions using low catalyst loadings viz.