Observation of Protonation-Induced Spin State Switching in a Cyanido-Bridged {FeCo} Molecular Square.

The self-assembly of [Co(MeTPyA)(CHCOO)]PF () and [Fe(bbp)(CN)] affords a cyanido-bridged square-shaped {FeCo} tetranuclear complex, [{Co(MeTPyA)(μ-NC)Fe(bbp)(CN)}]·3HO (; MeTPyA = tris((3,5-dimethylpyrazol-1-yl)methyl)amine and Hbbp = bis(2-benzimidazolyl)pyridine). The possibility of inducing an intramolecular electron transfer coupled spin transition in by employing protonation as an external stimulant is explored. UV-visible spectrophotometric measurements, electrochemical and H NMR studies establish that a reversible intramolecular electron transfer coupled spin transition can be triggered in upon addition of either acid or base.

Functionalized Silicas for Metal-Free and Metal-Based Catalytic Applications: A Review in Perspective of Green Chemistry.

Heterogeneous catalysis plays a key role in promoting green chemistry through many routes. The functionalizable reactive silanols highlight silica as a beguiling support for the preparation of heterogeneous catalysts. Metal active sites anchored on functionalized silica (FS) usually demonstrate the better dispersion and stability due to their firm chemical interaction with FSs.

Bimetallic Nanoparticles Anchored on Core-Shell Support as an Easily Recoverable and Reusable Catalytic System for Efficient Nitroarene Reduction.

We report an easily recoverable and reusable versatile magnetic catalyst (FeO@CS_AgNi, where CS = chitosan) for organic reduction reactions. The catalytic system is prepared by dispersing AgNi bimetallic nanoparticles on the magnetite core-shell (FeO@CS). The as-synthesized catalyst has been characterized by spectroscopic techniques, such as IR, UV-vis, and X-ray photoelectron spectroscopy (XPS), and analytical tools, such as thermogravimetric analysis, powder X-ray diffraction, Brunauer-Emmett-Teller adsorption, FEG-scanning electron microscopy, high-resolution transmission electron microscopy (HR-TEM), inductively coupled plasma-atomic emission spectroscopy, and magnetic measurements.

Spheroid Metallacycles and Metallocavitands with Calixarene- and/or Cleft-Shaped Receptors on the Surface.

Flexible hexatopic ligands, 1,2,3,4,5,6-hexakis(1H-naphtho[2,3-d]imidazol-1-ylmethyl)benzene (L(2)) and 1,2,3,4,5,6-hexakis(4,5-diphenylimidazol-1-ylmethyl)benzene (L(3)), containing six neutral naphthanoimidazolyl and 4,5-diphenylimidazolyl N donors were synthesized and used to assemble M6L6L'-type [M = Re(CO)3, L = anionic angular rigid NN donors, and L' = flexible hexatopic N donors] spheroid metallacycles. These molecules with a diameter of ∼17 Å were obtained from Re2(CO)10, H-L (imidazole, benzimidazole, and naphthanoimidazole), and L' [1,2,3,4,5,6-hexakis(benzimidazol-1-ylmethyl)benzene (L(1)), L(2), and L(3)] in a one-step process. Ligands L(2) and L(3) were characterized by elemental analysis, electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), and (1)H NMR spectroscopy.

Rhenium(I)-based bridgeless double metallocalix[4]arenes.

Bridgeless double metallocalix[4]arenes possessing two orthogonally arranged dinuclear cavitands were obtained from a Re2(CO)10, rigid bis-chelating OO donor (H2-L), and a flexible bis-ditopic NN donor (L') by a one-pot approach.