Starting from differently substituted boronic acids as versatile building block, new "ortho-aryl" alpha-diimine ligands a-h were synthesized in an easy, high-yielding route. Reaction of the complex precursor diacetylacetonato-nickel(II) with a trityl salt, like [CPh3] [B(C6F5)4] or [CPh3] [SbCl6], in the presence of the diimine ligands afford the monocationic, square planar complexes 2a-g in almost quantitative yields. Suitable crystals (2d',e,f,g) were submitted for X-ray diffraction analysis. A geometry model was developed to describe the orientation of ligand fragments around the nickel(II) center that influence the polymer microstructure. At elevated reaction temperature and pressure, and in the presence of hydrogen, 2a-e catalyze the homopolymerization of ethylene to give branched PE products ranging from HD- to LLD-PE grades. The polymerization results indicate the possibility of precise microstructure control depending on the particular complex substitution. Preliminary investigations on material density and mechanical behavior by uniaxial stretching until failure point toward new material properties that can result from the simple ethylene monomer by catalyst design.

The synthesis and first examples of structurally characterized, single-site palladium complexes containing a phosphine sulfonate chelate (PSO) for the nonalternating copolymerization of ethylene and carbon monoxide are reported. Extra incorporation of ethylene up to 30% has been achieved relative to the alternating polyketone structure with modest activities. As exemplarily shown, high molecular weight random copolymers have been produced with M w ≈ 370 000, polydispersity (M w/M n ) = 2, and melting points of 220−230 °C.

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The first examples of SHOP type nickel(II) catalysts bearing new phosphine chelate ligands comprised of a coordinating sulfonate functional group have been synthesized and structurally characterized. These catalysts show high activities in the polymerization of ethylene and can even be used without phosphine scaven-2775 gers. Polyethylenes with 15Ϫ25 branches per 1000 carbon atoms are produced from ethylene monomer alone. polar monomers are the features of this class of catalysts. Recently, Drent and coworkers reported the first example of random copolymers of ethylene and a variety of acrylates using in-situ derived palladium based catalysts with anionic chelating phosphine/ sulfonate [P,O] ligands. They were able to show by NMR that the vinyl units were incorporated directly into the linear polyethylene chain [14]. In turn, insitu and single site catalysts derived from these ligands, have also been shown to efficiently copolymerize ethylene and carbon monoxide under relatively mild conditions in a nonalternating way [15,16]. In this paper we present the syntheses and the first structurally characterized phenylnickel-(2phosphinobenzenesulfonate) triphenylphosphine complexes. Screening tests in polymerizations of ethylene were performed and compared to in-situ experiments.

The recently developed technique of energy-dependent electrospray ionisation mass spectrometry (EDESI-MS) has been implemented on a triple quadrupole mass spectrometer such that fragmentation occurs in the collision cell rather than at the skimmer cone. This modification enables a superior two-dimensional map of the collision voltage versus mass-to-charge ratio to be generated, providing unambiguous peak assignments. This latest enhancement to the technique is referred to as energy-dependent electrospray ionisation tandem mass spectrometry (EDESI-MS/MS). In the present work the technique has been applied to investigate the sequential removal of ligands from the inorganic mixed-metal anionic cluster compound [Ru 5 EXPERIMENTALAll mass spectra were collected using a Micromass Quattro LC instrument, in negative-ion mode, with methanol as the mobile phase. The nebuliser tip was set at 3100 V and 90°C, and nitrogen was used as the bath gas. Samples were introduced directly into the source at 4 mLmin À1 via a syringe pump. Data collection was carried out in continuum mode. For the EDESI mass spectrum, the cone voltage was initially set at 0 V. A scan time of 7 s per spectrum and a low resolution setting (peak width at half-height $0.8 Da) were used to maximise the signal-to-noise ratio. The cone voltage was manually increased by increments of 1 V after every scan up to a maximum of 200 V. A full scan from 0±200 V therefore took approximately 25 min to collect. The EDESI-MS/MS spectrum was collected by selecting the m/z 1024.5