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    ABSTRACT: The synthesis of the first tin-bridged bis(benzene) vanadium and trovacene sandwich compounds and the investigation of their oxidative addition and insertion behavior are reported. The vanadoarenophanes and the corre-sponding platinum insertion products were fully characterized including electrochemical and EPR measurements. Controllable ring-opening polymerization of the heteroleptic tin-bridged [1]trovacenophane using Karstedt's catalyst yields a high molecular weight polymer (up to Mn = 89,200 g mol-1) composed of d5-vanadium metal centers in the main chain, making it a rare example of a spin-carrying macromolecule. Magnetic susceptibility measurements (SQUID) confirm the paramagnetic scaffold with repeating S = ½ centers in the main chain and suggest antiferromagnetic interactions between adjacent spin sites (Weiss constant Θ = -2.9 K).
    Journal of the American Chemical Society 01/2015; 137(4). DOI:10.1021/ja510884h · 11.44 Impact Factor
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    ABSTRACT: Ambient-temperature photolysis of the aminoborylene complex [(OC)5CrBN(SiMe3)2] in the presence of a series of trans-bis(alkynyl)platinum(II) precursors of the type trans-[Pt(CCAr)2(PEt3)2] (Ar=Ph, p-C6H4OMe, and p-C6H4CF3) successfully leads to twofold transfer of the borylene moiety [:BN(SiMe3)2] onto the alkyne functionalities. The alkynyl precursors and resultant bis(borirene)platinum(II) complexes formed are of the type trans-[Pt(B{N(SiMe3)2}CCAr)2(PEt3)2] (Ar=Ph, p-C6H4OMe, and p-C6H4CF3). These species have all been successfully characterized by NMR, IR, and UV/Vis spectroscopy as well as by elemental analysis. Single-crystal X-ray diffraction has verified that these trans-bis(borirene)platinum(II) complexes display coplanarity between the twin three-membered rings across the platinum core in the solid state and stand as the first examples of coplanar conformations of twin borirene systems. These complexes were modeled using density functional theory (DFT), providing information helpful in determining the ability of the transition metal core to interact with each individual borirene ring system and allowing for the observed coplanarity of these rings in the solid state. This proposed transition metal interaction with the twin borirene systems is manifested in the electronic characterization of these borirene species, which display divergent photophysical UV/Vis spectroscopic profiles compared to a previously published mono(borirene)platinum(II) complex.
    Chemistry - A European Journal 11/2014; 21(6). DOI:10.1002/chem.201405803 · 5.70 Impact Factor
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    ABSTRACT: A new dimesitylboryl-functionalized molecule () and its corresponding N^C chelate platinum(ii) complex () have been synthesized and fully characterized. The photophysical and electronic properties of and were examined and compared to their constitutional isomers, and , respectively. Due to the presence of the electron-donating diphenylamino group, the and compounds exhibit intense donor-acceptor charge transfer (CT) and bright blue fluorescence. displays weak phosphorescence, originating from a mixture of MLCT/π→π* and CT transitions while displays bright phosphorescence originating from a CT transition. The Lewis acidity of the isomers was examined by fluoride titration experiments, which established that exhibits much higher affinity towards fluoride ions than . In addition, while the phosphorescence of is quenched by fluoride addition, demonstrates an unusual turn-on phosphorescent response towards fluoride ions, which illustrate the distinct impact of constitutional isomers on phosphorescence and anion sensing.
    Dalton Transactions 08/2014; 43(36). DOI:10.1039/c4dt01949k · 4.10 Impact Factor