Nickel precatalysts are potentially a more sustainable alternative to traditional palladium for the Suzuki–Miyaura coupling reaction. Currently, there is significant interest in reactions involving readily accessible phenolic derivatives such as aryl sulfamates, sulfamate moiety can act directing group prefunctionalization of aromatic backbone electrophile prior cross-coupling. By evaluating complexes Ni(0), (I), and (II) oxidation states we report precatalyst, (dppf)Ni(o-tolyl)(Cl) (dppf =...

Despite widespread use of complexes the type Pd(L)(η3-allyl)Cl as precatalysts for cross-coupling, chemistry related PdI dimers form (μ-allyl)(μ-Cl)Pd2(L)2 has been underexplored. Here, relationship between monomeric and dimeric compounds is investigated using both experiment theory. We report an efficient synthesis (μ-allyl)(μ-Cl)Pd2(IPr)2 (allyl = allyl, crotyl, cinnamyl; IPr 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) through activation Pd(IPr)(η3-allyl)Cl monomers under mildly...

The carboxylation of allenes with CO2 represents a potentially important method for the synthesis unsaturated carboxylic acids. Here, we describe detailed mechanistic study catalytic using CyPSiP (CyPSiP = Si(Me)(2-PCy2-C6H4)2) supported Pd complexes. As part this work have identified, characterized and isolated all proposed intermediates in cycle shown that they are kinetically competent catalysts. In addition, several off-cycle species, which equilibrium complexes cycle, established also...

Abstract Ni‐based precatalysts for the Suzuki–Miyaura reaction have potential chemical and economic advantages compared to commonly used Pd systems. Here, we compare Ni supported by dppf ligand in 3 oxidation states, 0, I II. Surprisingly, at 80 °C they give similar catalytic activity, with all systems generating significant amounts of during reaction. At room temperature a readily accessible bench‐stable II precatalyst is highly active can couple synthetically important heterocyclic...

Abstract The reaction of (μ‐Cl) 2 Ni (NHC) (NHC=1,3‐bis(2,6‐diisopropylphenyl)‐1,3‐dihydro‐2 H ‐imidazol‐2‐ylidene (IPr) or 1,3‐bis(2,6‐diisopropylphenyl)imidazolidin‐2‐ylidene (SIPr)) with either one equivalent sodium cyclopentadienyl (NaCp) lithium indenyl (LiInd) results in the formation diamagnetic NHC supported I dimers form (μ‐Cp)(μ‐Cl)Ni (NHC=IPr ( 1 a ) SIPr b ); Cp=C 5 (μ‐Ind)(μ‐Cl)Ni Ind=C 7 9 ), which contain bridging Cp and ligands. corresponding between two equivalents NaCp...

There is considerable interest in the controlled p-type and n-type doping of carbon nanotubes (CNT) for use a range important electronics applications, including development hybrid CNT/silicon (Si) photovoltaic devices. Here, we demonstrate that easy to handle metallocenes related complexes can be used both dope single-walled nanotube (SWNT) thin films, using simple spin coating process. We report n-SWNT/p-Si devices are >450 times more efficient than best solar cells this type currently...

The incorporation of multiple donors into the bulk‐heterojunction layer organic polymer solar cells (PSCs) has been demonstrated as a practical and elegant strategy to improve photovoltaics performance. However, it is challenging successfully design blend donors, while minimizing unfavorable interactions (e.g., morphological traps, recombination centers, etc.). Here, new Förster resonance energy transfer‐based shown utilizing synergistic nature three light active (two small molecules...

A family of imidazolium salts the type [BnN(CH2CH2CH2RIm)2]·2[Cl] (Bn = CH2Ph; RIm 1-methylimidazole (1a), 1-tert-butylimidazole (1b), 1-benzylimidazole (1c), 1-methylbenzimidazole (1d)), which contain a tertiary amine linking two groups, has been synthesized. These can be deprotonated with Ag2O to generate Ag carbene complexes [{BnN(CH2CH2CH2RIm)2}Ag]·[AgCl2] (RIm (2a), (2b), (2c), (2d)). In solid state 2d exists as an unusual tetramer, consists [Ag2Cl4]2− core bridging Ag(NHC) cations....

One of the most commonly used classes precatalysts for cross-coupling are Pd(II) complexes type (η3-allyl)Pd(L)Cl. Here, we report first full investigation how steric and electronic properties 2-substituent affect catalytic Specifically, have prepared studied a series well-defined 2-substituted (η3-2-R-allyl)Pd(IPr)Cl (R = H, Ph, Me, tBu, OMe, CN), as well their related Pd(I) (μ-2-R-allyl)(μ-Cl)Pd2(IPr)2 dimers. The performance monomers μ-allyl dimer congeners is compared Suzuki–Miyaura...

Pd and Ni dimers supported by PSiP ligands in which two hypervalent five-coordinate Si atoms bridge the metal centers are reported. Crystallographic characterization revealed a rare square-pyramidal geometry at an unusual asymmetric M2 Si2 core (M=Pd or Ni). DFT calculations showed that structure of is also found model phosphine not part pincer group, thus indicating observed imposed ligand. NBO analysis four-center two-electron (4c-2e) bond stabilizes core.

(POCOP)IrI(CO) [POCOP = κ3-C6H3-2,6-(OPR2)2 for R tBu, iPr] and (PCP)IrI(CO) [PCP κ3-C6H3-2,6-(CH2PR2)2 tBu complexes can add hydrogen via two distinct pathways. When (POCOP)Ir(CO) (PCP)Ir(CO) only a proton-catalyzed pathway due to steric effects, yielding trans-dihydride complexes. For iPr, both systems oxidatively give cis-dihydride which thermally isomerize more thermodynamically favorable species, consistent with previous reports. Proton-catalyzed addition pathways are also observed...

The synthesis of a series Pd and Ni complexes containing combinations 2-methylallyl (C4H7), cyclopentadienyl (C5H5, Cp), indenyl (C7H9, Ind) ligands is reported. In all cases these are supported by the electron-donating N-heterocyclic carbene ligand 1,3-bis(2,6-diisopropylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene (IPr). mixed Cp/2-methylallyl (η1-Cp)(η3-2-methylallyl)Pd(IPr) (CpAllPd) (η5-Cp)(η1-2-methylallyl)Ni(IPr) (CpAllNi) were synthesized through reaction IPr with (Cp)(2-methylallyl)M...

The PSiP pincer-supported complex (CyPSiP)PdH [CyPSiP = Si(Me)(2-PCy2-C6H4)2] has been implicated as a crucial intermediate in carboxylation of both allenes and boranes. At this stage, however, there is uncertainty regarding the exact structure (CyPSiP)PdH, especially solution. Previously, Pd(II) with terminal Pd hydride Pd(0) featuring an η2-silane have proposed. In contribution, range techniques were used to establish that related Pt species, (CyPSiP)PtH, are true M(II) hydrides solid...

The synthesis of three new Pd(I) dimers, (μ-All)(μ-Cp){Pd(PEt3)}2 (All = C3H5, Cp C5H5), (μ-All)(μ-Ind){Pd(PEt3)}2 (Ind C7H9), and (μ-Cp)(μ-Ind){Pd(PEt3)}2, which contain a combination bridging allyl, Cp, or indenyl ligands are all supported by triethylphosphine as the ancillary ligand, is reported. solid-state geometries, electronic structures, reactivity these compounds have been compared with those dimers (μ-All)2{Pd(PEt3)}2 (μ-Cp)2{Pd(PEt3)}2, previously This work establishes that there...

A pair of POCOP-supported mono- and dicarbonyl complexes Co have been prepared crystallographically characterized. The reactivity (tBuPOCOP)Co(CO) with H2, acids, carbon monoxide has compared to that the previously reported Rh Ir counterparts. is found share traits both Ir.

Abstract Ni‐based precatalysts for the Suzuki–Miyaura reaction have potential chemical and economic advantages compared to commonly used Pd systems. Here, we compare Ni supported by dppf ligand in 3 oxidation states, 0, I II. Surprisingly, at 80 °C they give similar catalytic activity, with all systems generating significant amounts of during reaction. At room temperature a readily accessible bench‐stable II precatalyst is highly active can couple synthetically important heterocyclic...

The reaction of tris(2-dimethylaminoethyl)amine (Me6tren) with Grignard reagents and related Mg precursors has been investigated. Treating Me6tren 2 equiv PhMgBr in diethyl ether resulted the formation [(Me6tren)MgBr]Br (1), which is bound a κ4 fashion. This first example complex containing or tris(aminoethyl)amine ligand. In contrast, when MeMgBr was treated either 1 Me6tren, mixture alkyl species [(Me6tren)MgMe]Br (3) produced. It not possible to separate two compounds generate pure sample...

Compared to analogous sterically demanding complexes, the methyl derived pincer iridium complex shows enhanced reactivity with H₂ including: rapid isomerization from a <italic>cis</italic>- <italic>trans</italic>-dihydride and solvent activation during isomerization.

The preparation and characterisation of two Mg coordination compounds supported by the tris(1-pyrazolyl)phosphine (P(pz)3) ligand, [{P(pz)3}Mg(MeCN)3](I)2 [Mg{P(pz)3}2](I)2, is described. This first time this ligand has been coordinated to or any other s-block metal complexes are examples crystallographically characterised P(pz)3 on metal. structures new compared with related species more common tridentate facial ligands, tris(pyrazolyl)hydroborate (Tp), tris(pyrazolyl)methane (Tpm),...

Abstract Pd and Ni dimers supported by PSiP ligands in which two hypervalent five‐coordinate Si atoms bridge the metal centers are reported. Crystallographic characterization revealed a rare square‐pyramidal geometry at an unusual asymmetric M 2 core (M=Pd or Ni). DFT calculations showed that structure of is also found model phosphine not part pincer group, thus indicating observed imposed ligand. NBO analysis four‐center two‐electron (4c‐2e) bond stabilizes core.

The reactions of the substituted 2,2':6,2''-terpyridine ligands, 4'-mesityl-2,2':6',2''-terpyridine (mesitylterpy) (1a), 4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine (tri-(t)Buterpy) (1b) and 4'-phenyl-2,2':6',2''-terpyridine (phenylterpy) (1c) with Grignard reagents were investigated. When half an equivalent mesitylterpy or tri-(t)Buterpy treated MeMgBr in diethyl ether, only products (R-terpy)MgBr(2) (R = mesityl (5a), tri-(t)Bu (5b)) Me(2)Mg a similar reaction was observed THF....

A new pincer ligand framework based on the commonly used "POCOP" (POCOP = κ3-C6H3-1,3-(OPR2)2, R tBu, iPr) motif is reported, in which two POCOP units are tethered using an anthracene linker to support bimetallic complexes. Metalation Ir precursors affords products dictated by steric factors. comparison of reactivity RPOCOP-supported Ir(I) carbonyl monomeric and dimeric species with alkyl halides explored. For complexes unreactive, but for iPr, both types react form Ir(III) products.

Somatostatin receptor subtype 4 (SSTR4) antagonists are potential clinical targets for pain. We describe the efforts toward a robust large-scale synthesis of certain small-molecule SSTR4 agonist compounds. Previous routes used metal-mediated reactions and produced stereochemical mixtures. The molecule has 3-azabicyclo[3.1.0]hexane ring system with cis-stereochemistry. A unique tandem cyclization at multi-kilogram scale was employed to generate fused exclusive cis-stereochemistry observed....