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A study was conducted wherein an efficient new boron-tethered Diels-Alder reaction using alkenyl boronic esters as dienophilic components was established. Likewise, the impact of the tether length on the efficacy and the mode of diastereoselectivity of the reaction was demonstrated. Results suggested that the ready availability of alkenyl boronic acids and the synthetic flexibility of the C-B bond in cycloadducts is expected to provide access to a variety of functionalized cyclohexene derivatives.

The ability of the cation (K(1,10-diaza-18-crown-6))+ to organize anionic polyhydride compounds into a new one-dimensional chain structure in the solid state with proton-hydride bonds that are crystallographically well-defined was investigated. Experimental results showed that the (K(18-crown-6))+ salts without hydrogen bonds have totally different chain structures. Furthermore, stronger proton-hydride interaction occurs in the case of the more basic anionic hydride.

The title solvated complex, [FePd(C5H5)(C12H13N2S)Cl(C18H15P)2]PF6 · 2CHCl3, bearing a chiral ferrocenyl pyrroloimidazolylidene N-heterocyclic carbene (NHC) ligand, was synthesized by oxidative addition of a chloroimidazolium salt to Pd(PPh3)4. The PdII ion is coordinated in a slightly distorted square-planar coordination geometry, with the Cl atom trans to the coordinating C atom of the pyrroloimidazolylidene ligand. The complex features a pendant thioether group that is not involved in coordination to Pd. In the crystal, weak C-H...Fand C-H...π interactions connect the components of the structure, forming chains propagating along [110]. The fused pyrrolidine ring is in an envelope conformation, and the flap atom was refined as disordered over two sets of sites, with occupancies of 0.77 (4) and 0.23 (4). [ABSTRACT FROM AUTHOR]

A simple modular approach is presented which has been directed towards the synthesis of potentially monoanionic NN'N", NN'C, and NN'P pincer-type ligands. These pincers incorporate an amide functionality derived from the skeletal structure of readily available 2-(2-aminophenyl)-4,5-dioxooxazoles. All of the pincers are synthesized in moderate yields (up to 74%) and are characterised by nuclear magnetic spectroscopy (NMR), elemental analyses, and infrared (IR) spectroscopy. X-ray crystallography is also performed on the chiral and achiral alkyl halide precursors and on an oxide derivative of a pincer with a NN'Patom donor set. A palladium derivative of one of the NN'N"-pincers is shown to be an active catalyst for the addition of an allyl group to various benzaldehydes using n-Bu3Sn(allyl) as allyl source. [ABSTRACT FROM AUTHOR]

Chloro-boron subnaphthalocyanine (Cl-BsubNc) has recently attracted significant interest as a light-harvesting and charge transporting material in organic photovoltaic devices (OPVs) by enabling an 8.4% efficient planar heterojunction OPV cell. We present herein a variety of experimental data that supports the conclusion that Cl-BsubNc, whether synthesized via literature methods or our in-house methods or purchased commercially, is actually a mixed alloyed composition of Cl-BsubNcs with random amounts of chlorination at the bay position(s) of the BsubNc macrocyclic structure which we hereafter will refer to as Cl–ClnBsubNc(s). We outline our efforts to develop alternative chemical processes, whereby we did obtain samples with lower and higher amounts of bay position chlorination. However, we were unable to obtain a pure, non-bay chlorinated sample of Cl-BsubNc. The positions and frequencies of the peripheral chlorine atoms were determined via single crystal X-ray crystallography of two different mixed alloyed compositions of Cl–ClnBsubNc samples and MS and XPS analysis of all Cl–ClnBsubNc samples. The photo- and electro-physical properties were found to differ amongst the Cl–ClnBsubNc samples with varying amounts of chlorination. These differences also translated into varying performance within planar heterojunction OPVs, whereby a mixture of Cl–ClnBsubNcs with lower amounts of chlorination produced less efficient OPVs (albeit with a higher open circuit voltage) compared to a mixture with higher amounts of chlorination. Additionally, an in-house made sample of Cl–ClnBsubNc, with the highest level of bay position chlorination, yielded the best performing OPVs through an improved fill factor. A commercial sample of Cl–ClnBsubNc also yielded OPVs with efficiencies equivalent to a Cl–ClnBsubNc sample prepared in our laboratory. This mixture of Cl–ClnBsubNcs is therefore likely to be present in the reported 8.4% efficient OPV device. Our results therefore offer a cautionary note that the Cl-BsubNc samples used within the existing literature are likely not a pure chemical composition but are rather mixtures of Cl–ClnBsubNcs with bay position chlorination. Our findings clarify the previous literature results on the chemistry of Cl-BsubNc, firm up the photo- and electro-physical properties of these materials, and offer additional insight into their application as functional materials in efficient OPVs. [ABSTRACT FROM AUTHOR]

We report the preparation and electronic structure of a nickel complex 2 containing ligand 6-(8-quinolylamino)-2,4-bis( tert -butyl)phenol 1 . The complex is neutral, six-coordinate (pseudo-octahedral) and homoleptic containing two equivalents of 1 and no counteranions. The bond distances measured by single crystal X-ray diffraction studies suggest that the two equivalents of 1 are bound as mono-anion radicals (iminosemiquinone oxidation state). Variable temperature magnetic susceptibility data indicates a quintet ( S = 2) ground state for this complex resulting from ferromagnetic coupling between Ni 2 + and the coordinated radical anions. Cyclic voltammetry experiments and UV–Vis–NIR spectroscopy indicate the presence of coordinated iminosemiquinone radicals, and these experimental results are corroborated by density functional theory calculations, which support the proposed assignments. Complex 2 is easily oxidized in the presence of ferrocenium hexafluorophosphate or aerial dioxygen to produce a complex with closed shell ligands and spectroscopic features characteristic of ortho -iminoquinone ligands. [ABSTRACT FROM AUTHOR]

We report the structural properties and electronic structure of a neutral homoleptic copper(II) complex bearing the anion of 1-(2-pyridylazo)-2-phenanthrol (papl). In the solid state the complex is disordered and this presents itself as a nearly equal mixture of five and six coordinate copper ions with the ligand bound in two different configurations, with one of the terminal pyridine rings uncoordinated in the case of the five coordinate ion, which also features a very short Cu–N azo coordinate bond. The six coordinate complex features a Jahn–Teller elongated octahedron with one of the ligands coordinated in a typical fashion with coordinate bond distances typical of other divalent ion–papl complexes while the distances to the other donor atoms are much longer. [ABSTRACT FROM AUTHOR]

The reaction between protonated 2-pyridine thiol and IrH5(PCy3)(2) in ethanol at minus 80 degrees Celsius yields a mononuclear complex that reveals a novel interaction between an iridium hydride and the protonated nitrogen of a sulfur-bonded thiopyridine ligand. X-ray studies demonstrate IrH-HN interactions in solution. The hydrogen bond unit is absent in the presence of good hydrogen-bond acceptors. The H...H interaction is necessary for fast H/D exchange with D2 gas.

An analysis of the reaction of ferrocenyllithium FcLi (Fc = Fe(eta-C5H4)(eta-C5H5)) with strained, ring-tilted silicon-bridged ferrocenophane which produces polymeric or oligomeric products based on the reactant's mole ratio reveals that anionic ring-opening polymerization of the ferrocenophane can provide oligomers and polymers of reasonable molecular weight. Peaks associated with a molecular ion and logical fragmentation products are evident in the mass spectrum of each oligomer.