The nonheme iron(IV)-oxido complex trans-N3-[(L 1 ) Fe IV = O(Cl)] + , where L 1 is a derivative of the tetradentate bispidine 2,4-di(pyridine-2-yl)-3,7-diazabicyclo[3.3.1]nonane-1one, is known to have an S = 1 electronic ground state and to be an extremely reactive oxidant for oxygen atom transfer (OAT) and hydrogen atom abstraction (HAA) processes. Here we show that, in spite of this ferryl oxidant having the "wrong" spin ground state, it is the most reactive nonheme iron model system known so far and of a similar order of reactivity as nonheme iron enzymes (CÀ H abstraction of cyclohexane, À 90°C (propionitrile), t 1/2 = 3.5 sec). Discussed are spectroscopic and kinetic data, supported by a DFT-based theoretical analysis, which indicate that substrate oxidation is significantly faster than self-decay processes due to an intramolecular demethylation pathway and formation of an oxido-bridged diiron(III) intermediate. It is also shown that the iron(III)-chlorido-hydroxido/cyclohexyl radical intermediate, resulting from CÀ H abstraction, selectively produces chlorocyclohexane in a rebound process. However, the lifetime of the intermediate is so long that other reaction channels (known as cage escape) become important, and much of the CÀ H abstraction therefore is unproductive. In bulk reactions at ambient temperature and at longer time scales, there is formation of significant amounts of oxidation product -selectively of chlorocyclohexane -and it is shown that this originates from oxidation of the oxido-bridged diiron (III) resting state.

Eu III , Tb III , Gd III and Yb III complexes of the nonadentate bispidine derivative L 2 (bispidine = 3,7-diazabicyclo [3.3.1]nonane) were successfully synthesized and their emission properties studied. The X-ray crystallography reveals full encapsulation by the nonadentate ligand L 2 that enforces to all Ln III cations a common highly symmetrical capped square antiprismatic (CSAPR) coordination geometry (pseudo C 4v symmetry). The well-resolved identical emission spectra in solid state and in solution confirm equal structures in both media. As therefore expected, this results in long-lived excited states and high emission quantum yields ([Eu III L 2 ] + , H 2 O, 298 K, τ = 1.51 ms, ϕ = 0.35; [Tb III L 2 ] + , H 2 O, 298 K, τ = 1.95 ms, ϕ = 0.68). Together with the very high kinetic and thermodynamic stabilities, these complexes are a possible basis for interesting biological probes.

9-Gallafluorenes were synthesized from 9-zincafluor-ene·tmeda as an alternative to 2,2′-biphenylenmercury and 2,2′-dilithiobiphenyl. The zincafluorene was found to be only one possible form of a biphenylene zinc. In dependence of the synthetic conditions a dimeric zinc bridged structure resulted, too. The gallafluorenes obtained were stabilized by nitrogen donors or formed dimers in case of 9-tert-butoxygallafluorene. That means, all of these derivatives contained tetra coordinated

The novel polyhedral closo‐Ga6 and Ga8 cluster ions [Ga6(R5)6]2– and [Ga8I4(R5)4]2– have been prepared as their lithium salts from reaction of the corresponding lithium silanide with a gallium subtriflate and “GaI”, respectively, together with the expected disproportionation products. All new compounds have been structurally characterized by single crystal X ray crystallography. The hexagallium cluster has a regular octahedral core, which is expected for a seven‐SEP cluster. The unexpected disphenoidal structure for the octagallium nine‐SEP cluster was compared to the square antiprismatic isomer by means of DFT calculations. In addition DFT calculations with dispersion correction on digallanes(4) R4Ga2 allow a new look on bonding in this gallium–gallium bonded compounds.

The interaction of Eu(III) and Cm(III) with three different aquatic fulvic acids (FA) was studied as a function of the temperature (T = 20-80 °C) in 0.1 M NaCl solution by time-resolved laser fluorescence spectroscopy. The speciation of both trivalent metal ions was determined by peak deconvolution of the recorded fluorescence spectra. For each studied metal ion-FA system only one complexed species is formed under the given experimental conditions. The stability constants at 20, 40, 60 and 80 °C (log β'(T)) were determined according to the charge neutralization model. The log β' (20 °C) for the different FAs show similar values (log β(20 °C) = 5.60-6.29). The stability constants increase continuously with increasing temperature by approximately 0.3-1.0 orders of magnitude. The reaction enthalpies and entropies are derived from the integrated Van't Hoff equation. The results show that all investigated complexation reactions are endothermic and entropy-driven.