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New PCNPy pincer nickel complexes have been synthesized through a short synthetic route. Incorporating pyridine as the nitrogen side arm facilitated the C–H activation in the PCN ligand and allowed the cyclometallation with nickel to take place at room temperature. Pyridine also enhanced the stability of β-hydrogen-containing alkyl complexes. Also, the symmetric NCN nickel complex with pyridine side arms was successfully obtained giving a rare example of such type of complexes to be prepared through direct C–H activation. Furthermore, preliminary results showed that the (PCNPy)Ni–Br is active in Kumada coupling reactions particularly the coupling of aryl halides with aryl Grignard reagents.

The synthesis of a new unsymmetrical PCN ligand bearing tert-butyl groups on the phosphorus atom and isopropyl groups on the nitrogen donor atom is presented. It reacts with the commercially availa...

Injectable bioelectronics could become an alternative or a complement to traditional drug treatments. To this end, a new self-doped p- type conducting PEDOT-S copolymer (A5) was synthesized. This copolymer formed highly water-dispersed nanoparticles and aggregated into a mixed ion-electron conducting hydrogel when injected into a tissue model. First, we synthetically repeated most of the published methods for PEDOT-S at the lab scale. Surprisingly, analysis using high-resolution matrix-assisted laser desorption ionization-mass spectroscopy showed that almost all the methods generated PEDOT-S derivatives with the same polymer lengths (i.e., oligomers, seven to eight monomers in average); thus, the polymer length cannot account for the differences in the conductivities reported earlier. The main difference, however, was that some methods generated an unintentional copolymer P(EDOT-S/EDOT-OH) that is more prone to aggregate and display higher conductivities in general than the PEDOT-S homopolymer. Based on this, we synthesized the PEDOT-S derivative A5, that displayed the highest film conductivity (33 S cm(-1)) among all PEDOT-S derivatives synthesized. Injecting A5 nanoparticles into the agarose gel cast with a physiological buffer generated a stable and highly conductive hydrogel (1-5 S cm(-1)), where no conductive structures were seen in agarose with the other PEDOT-S derivatives. Furthermore, the ion-treated A5 hydrogel remained stable and maintained initial conductivities for 7 months (the longest period tested) in pure water, and A5 mixed with Fe3O4 nanoparticles generated a magnetoconductive relay device in water. Thus, we have successfully synthesized a water-processable, syringe-injectable, and self-doped PEDOT-S polymer capable of forming a conductive hydrogel in tissue mimics, thereby paving a way for future applications within in vivo electronics. Funding Agencies|Swedish Research Council [2018-05258, 2018-06197]; Swedish Foundation for Strategic Research (e-NeuroPharmacology) [RMX18-0083]; European Research Council (ERC) project [e-NeuroPharma 834677]

New diamagnetic nickel(II) complexes based on an unsymmetrical (1-(3-((ditert-butylphosphino)methyl)phenyl)-N,N-dimethyl-methanamine) (PCN) pincer ligand were synthesized and characterized by 1H, 31P{1H}, and 13C{1H} NMR spectroscopy. Their molecular structures were confirmed by X-ray diffraction. Oxidation to high-valent paramagnetic Ni(III) dihalide complexes was achieved through straightforward reaction of the corresponding diamagnetic halide complexes with anhydrous CuX2 (X = Cl, Br). In agreement with this, the complexes are active in Kharasch addition of CCl4 to olefins. The reaction of the hydroxo complex (8) and the amido complex (11) with CO2 produced the hydrogen carbonate and carbamate complexes, respectively. The hydrogen carbonate complex was converted to the dinuclear nickel carbonate complex (10). The methyl (13), phenyl (14), and p-tolylacetylide (15) complexes are also described in the current study providing the first example of the hydrocarbyl nickel complexes based on an unsymmetric ar...

A nickel(II) hydroxo complex (3) supported by a cyclohexyl based POCsp3OP pincer ligand (POCsp3OP = cis-1,3-Bis-(di-tert-butylphosphinito)cyclohexyl) is reported. Complex 3 reacts with CO to form the corresponding hydroxycarbonyl complex, (POCsp3OP)NiCOOH (4). Complex 3 is also reactive towards CO2, forming a bicarbonate species (5) that under reduced pressure loses ½ eq. of H2O and CO2 to give a binuclear, bridged carbonate complex (6). All compounds were characterized in the solid state by X-ray diffraction.

Through a salt metathesis reaction, ( t −Bu PCN)Pd-ONO 2 ( 2 ) was prepared and used as a precursor for producing ( t −Bu PCN)Pd-OH ( 3 ) and ( t −Bu PCN)Pd-aryl acetylide complexes 4 (phenyl acetylide) and 5 (p-tolyl acetylide). The aryl acetylide complexes could also be prepared through another synthetic route: by condensation of 3 with the corresponding aryl acetylene. The reactivity of complexes 3 and 4 toward carbon dioxide was studied and it was found that both reactions give the hydrogen carbonate complex ( 6 ). The low reactivity of the Pd-acetylide bond was further confirmed by the fact that the propiolate complex undergoes decarboxylation to give 4 . PCN palladium complexes are good catalysts for the decarboxylative cross coupling reactions between acetylene carboxylic acids and aryl halides. The yield of the cross coupling product was improved by adding a catalytic amount of CuI.

A series of unsymmetrical PCN pincer ligands (1-(3-((di-tert-butylphosphino)methyl)phenyl)-N,N-dialkylmethanamine) were cyclometalated with palladium to generate a series of new PCN supported Pd(II) chloro complexes, (PCN)PdCl (4–6), where alkyl = methyl, ethyl, and n-propyl, which were fully characterized by NMR spectroscopy and X-ray crystallography. The N,N-dimethyl complex 4 reacts with methyl lithium to give the corresponding methyl and dimethyl complexes (PCN)PdMe (12) and Li[(PCN)PdMe2] (13), which could not be isolated but were characterized in solution. The substitution reactions of (PCN)PdCl (4–6) with iodide to form the corresponding iodo complexes (PCN)PdI (7–9) were investigated by use of UV–vis stopped-flow spectrophotometry. The experiments were performed in methanol over a temperature range from 293 to 325 K. The reactions are reversible and were shown to proceed exclusively via the solvento complex in two reversible consecutive steps. Activation parameters for both the forward and reverse...

Multiple exciton generation (MEG) is a process in which more than one exciton is generated upon the absorption of a high energy photon, typically higher than two times the band gap, in semiconductor nanocrystals. It can be observed experimentally using time resolved spectroscopy such as the transient absorption measurements. Quantification of the MEG yield is usu- ally done by assuming that the bi-exciton signal is twice the signal from a single exciton. Herein we show that this assumption is not always justified and may lead to significant errors in the estimated MEG yields. We develop a methodology to determine proper scaling factors to the signals from the transient absorption experiments. Using the methodology we find modest MEG yields in lead chalcogenide nanocrystals including the nanorods.

Organic electrochemical transistors formed by in operando electropolymerization of the semiconducting channel are increasingly becoming recognized as a simple and effective implementation of synapses in neuromorphic hardware. However, very few studies have reported the requirements that must be met to ensure that the polymer spreads along the substrate to form a functional conducting channel. The nature of the interface between the substrate and various monomer precursors of conducting polymers through molecular dynamics simulations is investigated, showing that monomer adsorption to the substrate produces an increase in the effective monomer concentration at the surface. By evaluating combinatorial couples of monomers baring various sidechains with differently functionalized substrates, it is shown that the interactions between the substrate and the monomer precursor control the lateral growth of a polymer film along an inert substrate. This effect has implications for fabricating synaptic systems on inexpensive, flexible substrates. Funding: Swedish Foundation for Strategic Research [RMX18-0083]; Swedish Research Council [2018-06197]; European Research Council [834677]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; Knut and Alice Wallenberg Foundation; Onnesjo Foundation