Pyrazolate-supported Cr(μ-O) cores; homovalent CrIII3 and mixed-valent CrIII2Cr.

The thermally assisted reaction of Cr(NO)·9HO, 4-Cl-pzH, and EtN yielded electrochemically active trinuclear Cr-oxo-pyrazolate complexes with formula (PhP)[Cr(μ-O)(μ-4-Cl-pz)X], X = Cl (1) and Br (2). Magnetic susceptibility measurements and EPR spectroscopy show that 1 has an antiferromagnetically coupled CrO-core with an = 1/2 ground state and isotropic exchange of = -12.7 cm.

Impact of counteranions on N-heterocyclic carbene gold(i)-catalyzed cyclization of propargylic amide.

N-Heterocyclic carbene (NHC) Au(i)-catalyzed organic synthesis has recently been receiving increasing attention, especially with the activation of alkynes. In contrast, counteranions, being widely problematic in Au(i)-catalyzed transformations, are commonly considered as innocent partners and are not respectably included in a computational model. Herein, we report density functional theory (DFT) investigations of the Au(i)-catalyzed cyclization of propargylic amides to exploit the mechanistic effect of several counteranions to shed some light for further future developments.

The nature of metal-metal bonding in Re-, Ru- and Os-corrole dimers.

Studies of multiple bonding between transition metal complexes offer fundamental insight into the nature of bonding between metal ions and facilitate predictions of the physical properties and the reactivities of metal complexes containing metal-metal multiple bonds. Here we report a computational interrogation on the nature of the metal-metal bonding for neutral, oxidized, and reduced forms of dinuclear rhenium and osmium corrole complexes, [{Re[TpXPC]}] and [{Os[TpXPC]}], using a complete active space self-consistent (CASSCF) methodology and density functional theory (DFT) calculations. For [{Re[TpXPC]}], [{Ru[TpXPC]}], and [{Os[TpXPC]}], CASSCF calculations shows that the effective bond order is 3.

Structural, spectroscopic and electronic properties of a family of face-shared bi-octahedral Ru complexes with a bridging 2,5-di(2-pyridyl)pyrrolide ligand.

A family of Ru2 dimers, [Ru2(μ-κ2N,N':κ2N',N''-dpp)2(μ-X)(X)2]q+ (X = Cl, Br, q = 0 and X = I, q = 1) is synthesized from a [Ru2(OAc)4Cl] paddlewheel starting material. The neutral products are mixed-valence Ru25+ dimers with a Ru-Ru bond order of 0.5, while the cationic iodide is a Ru26+ dimer with formal bond order of 1.

Redox-Dependent Metal-Metal Bonding in Trinuclear Metal Chains: Probing the Transition from Covalent Bonding to Exchange Coupling.

The synthesis and physical properties of two new cationic tri-metallic chains, [(PEt ) RuCl M'Cl Ru(PEt ) ] , M'=Rh and Ir are reported. These are isostructural with a previously reported 17-electron all-ruthenium analogue, but replacing a d Ru ion in the central position with d Rh /Ir has a significant impact on the nature of the metal-metal interactions. All three materials have been characterized electrochemically at the 18-, 17- and 16-electron levels.