Half-sandwich hydrazine complexes of iridium: Preparation and reactivity

Synthesis and Characterization of Bridging-Diazene Diiron Half-Sandwich Complexes: The Role of Sulfur Hydrogen Bonding

We report two bridging-diazene diiron complexes [Cp*Fe(8-quinolinethiolate)]2(μ-N2H2) (1-N2H2) and [Cp*Fe(1,2-Cy2PC6H4S)]2(μ-N2H2) (2-N2H2), synthesized by the reaction of hydrazine with the corresponding thiolate-based iron half-sandwich complex, [Cp*Fe(8-quinolinethiolate)]2 (1) and Cp*Fe(1,2-Cy2PC6H4S) (2). Crystallographic analysis reveals that the thiolate sites in 1-N2H2 and 2-N2H2 can engage in N-H···S hydrogen bonding with the diazene protons. 1-N2H2 is thermally stable in both solid and solution states, allowing for one-electron oxidation to afford a cationic diazene radical complex [1-N2H2]+ at room temperature. In contrast, 2-N2H2 tends to undergo N2H2/N2 transformation, leading to the formation of a Fe(III)-H species by the loss of N2. In addition to stabilizing HN=NH species through the hydrogen bonding, the thiolate-based ligands also seem to facilitate proton-coupled electron transfer, thereby promoting N-H cleavage.

A diazene-bridged diruthenium complex with structural restraint defined by single meta-diphosphinobenzene

Creation of confined coordination spaces with controlled flexibility is of importance in mimicking enzymatic reactions. We found that a simple, non-chelating 1,3-bis(diphenylphosphino)benzene (DPPBz) assembled two Cp*Ru units to give a dinuclear complex, wherein only one DPPBz supports an open framework without metal-metal bonding. Subsequent treatment with an excess of hydrazine resulted in formal 2e^-/2H⁺ transfer from hydrazine to afford a diazene-bridged complex featuring intramolecular NHCl hydrogen bonds. In constrast, a monophosphine failed to stabilize the diazene-bridged dinuclear structure due to the lack of the enforcement of the conformation.

Pentamethylcyclopentadienyl half-sandwich hydrazine complexes of ruthenium: preparation and reactivity

The preparation and selective oxidation of hydrazine complexes of ruthenium stabilised by a pentamethylcyclopentadienyl fragment are described. The formation of the sandwich complex [Ru(η⁵-C₅Me₅)(η⁶-C₆H₆)]BPh₄ through the oxidation of coordinate phenylhydrazine is also reported.

Preparation of metalated azine complexes of iridium(iii)

The preparation of half-sandwich κ¹-aldazine and κ¹-ketazine complexes of iridium and their metalation reaction affording chelate κ²-azine derivatives are described. The photoluminescence properties of the chelate complexes are also described.