Cyclopentadienyl molybdenum hydride compounds are catalysts for dehydrogenation, disproportionation and transfer hydrogenation reactions of formic acid, in which the latter provides a means to reduce aldehydes and ketones.

The synthesis and characterization of core-shell Fe 3 O 4 @organic@Au nanoparticles displaying plasmonic behavior, high magnetism, and high relaxivity is presented. The incorporation of a thin organic layer between the two metals is crucial to maintaining the saturation magnetisation of the superparamagnetic core.Magnetic Iron Oxide Nanoparticles (MIONs) are increasingly used as MRI contrast agents due to their high saturation magnetisation (M S ) which leads to high transverse relaxivity.1 Likewise, gold nanoparticles have become the material of choice in imaging techniques that exploit their plasmonic properties such as dark field spectroscopy and Surface Enhanced Raman Spectroscopy (SERS).2 The combination of these two materials in a single nanocomposite displaying both magnetic and plasmonic properties, a so-called magnetoplasmonic assembly,3 is particularly attractive given the complementarity in terms of resolution and 3D imaging capabilities of the plasmonic and MR imaging techniques.1 , 2 Herein we present the synthesis and characterization of magnetite@organic layer@gold core-shell nanocomposites which display high saturation magnetisation due to the presence of a thin organic layer.Multimodal nanocomposites comprised of both iron oxide and gold components can be synthesized in either of two ways. In the first case, both nanoparticles of gold and iron oxide are embedded in a polymer or silica coating.3 , 4 This approach unfortunately results in assemblies of size typically around 150-200 nm, which are too large for cellular imaging and for most in vivo applications.5 Alternatively, a core-shell structure, typically with an iron oxide core and an outermost gold layer, enables the synthesis of smaller nanoparticles, typically 80 nm in diameter. Advantageously, these assemblies can also be readily functionalized with biomolecules since the chemistry of conjugation of proteins and nucleic acids to gold surfaces is well established.6 -9 The disadvantages of these structures is twofold. First, the coating on the iron oxide core, which includes the gold layer, is typically ca. 35 nm thick or more. Since this thick coating increases the distance separating the magnetic core from the solvent water molecules, both the longitudinal and the transverse relaxivities of the material are significantly reduced.1 Secondly, and importantly, direct coating of gold onto iron oxide nanoparticles severely decreases the saturation † Electronic Supplementary Information (ESI) available: Detailed experimental procedure and characterization of the nanoparticles. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript magnetization (on a per iron basis) of the magnetic core by 78% or more.9 , 10 This further reduces the relaxivities, and hence the potency of the nanocomposites as MR contrast agents.The mechanism by which the gold coating decreases the saturation magnetisation of the magnetite core is presently not well understood. Similar effects have been observed in gold coated cobalt nanoparticles.11 ...

Catalysis is the second largest application for V after its use as an additive to improve steel production. Molecular complexes of vanadium(V) are particularly useful and efficient catalysts for oxidation processes; however, their ability to catalyze reductive transformations has yet to be fully explored. Here we report the first examples of polar organic functionality reduction mediated by V. Open-shell V III complexes that feature a π-radical monoanionic 2,2′:6′,2″-terpyridine ligand (Rtpy • ) − functionalized at the 4′-position (R = (CH 3 ) 3 SiCH 2 , C 6 H 5 ) catalyze mild and chemoselective hydroboration and hydrosilylation of functionalized ketones, aldehydes, imines, esters, and carboxamides with turnover numbers (TONs) of up to ∼1000 and turnover frequencies (TOFs) of up to ∼500 h −1 . Computational evaluation of the precatalyst synthesis and activation has revealed underappreciated complexity associated with the redox-active tpy chelate.