Homocoupling of CO and isocyanide mediated by a C,C′-bis(silylenyl)-substituted ortho-carborane

The unexpected reactivity of the o-carborane supported bis-silylene [(LSi:)C]2B10H101 {L= PhC(tBuN)2} towards carbon monoxide and 2,6-dimethylphenyl isocyanide is reported. While the reaction of 1 with CO leads selectively to the novel head-to-head coupling and C–O cleavage product 2 from two molecules 1 and four molecules CO, the reaction of 1 with 2,6-dimethylphenyl isocyanide affords solely the 1 : 2 molar head-to-tail coupling product 3 with a Si[double bond, length as m-dash]C bond.TU Berlin, Open-Access-Mittel - 201

Facile rotation around a silicon-phosphorus double bond enabled through coordination to tungsten

Correction: Citation missing unintentionally. Missing intention is included in the additional file. To cite the Correction refer to DOI:10.1039/c5cc04247

The correlation theory of the chemical bond

The quantum mechanical description of the chemical bond is generally given in terms of delocalized bonding orbitals, or, alternatively, in terms of correlations of occupations of localised orbitals. However, in the latter case, multiorbital correlations were treated only in terms of two-orbital correlations, although the structure of multiorbital correlations is far richer; and, in the case of bonds established by more than two electrons, multiorbital correlations represent a more natural point of view. Here, for the first time, we introduce the true multiorbital correlation theory, consisting of a framework for handling the structure of multiorbital correlations, a toolbox of true multiorbital correlation measures, and the formulation of the multiorbital correlation clustering, together with an algorithm for obtaining that. These make it possible to characterise quantitatively, how well a bonding picture describes the chemical system. As proof of concept, we apply the theory for the investigation of the bond structures of several molecules. We show that the non-existence of well-defined multiorbital correlation clustering provides a reason for debated bonding picture

Cationic Tetrylene‐Iron(0) Complexes: Access Points for Cooperative, Reversible Bond Activation and Open‐Shell Iron(−I) Ferrato‐Tetrylenes

The open-shell cationic stannylene-iron(0) complex 4 (4=[PhiPDippSn⋅Fe⋅IPr]+; PhiPDipp={[Ph2PCH2Si(iPr)2](Dipp)N}; Dipp=2,6-iPr2C6H3; IPr=[(Dipp)NC(H)]2C:) cooperatively and reversibly cleaves dihydrogen at the Sn−Fe interface under mild conditions (1.5 bar, 298 K), in forming bridging hydrido-complex 6. The One-electron oreduction of the related GeII−Fe0 complex 3 leads to oxidative addition of one C−P linkage of the PhiPDipp ligand in an intermediary Fe−I complex, leading to FeI phosphide species 7. One-electron reduction reaction of 4 gives access to the iron(−I) ferrato-stannylene, 8, giving evidence for the transient formation of such a species in the reduction of 3. The covalently bound tin(II)-iron(−I) compound 8 has been characterised through EPR spectroscopy, SQUID magnetometry, and supporting computational analysis, which strongly indicate a high localization of electron spin density at Fe−I in this unique d9-iron complex.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Verband der Chemischen Industrie http://dx.doi.org/10.13039/100007215Peer Reviewe

CO2 fixation and catalytic reduction by a neutral aluminum double bond

CO2 fixation and reduction to value‐added products is of utmost importance in the battle against rising CO2 levels in the Earth's atmosphere. An organoaluminum complex containing a formal aluminum double bond (dialumene), and thus an alkene equivalent, was used for the fixation and reduction of CO2. The CO2 fixation complex undergoes further reactivity in either the absence or presence of additional CO2, resulting in the first dialuminum carbonyl and carbonate complexes, respectively. Dialumene (1 ) can also be used in the catalytic reduction of CO2, providing selective formation of a formic acid equivalent via the dialuminum carbonate complex rather than a conventional aluminum–hydride‐based cycle. Not only are the CO2 reduction products of interest for C1 added value products, but the organoaluminum complexes isolated represent a significant step forward in the isolation of reactive intermediates proposed in many industrially relevant catalytic processes

Identifying the Rate-Limiting Elementary Steps of Nitrogen Fixation with Single-Site Fe Model Complexes

Biomimetic nitrogen fixation provides an attractive alternative for the century-old Haber−Bosch process; however, the performance of the currently available molecular biomimetic catalysts is very limited. In this work, we are aiming to understand the catalytic cycle of one of the most promising biomimetic complex families that can be the cornerstone of future computer-aided rational design of biomimetic complexes. We calculate the Gibbs free energy of all elementary reaction steps of homogeneous dinitrogen reduction to NH3 on singlesite iron complexes with EPPP tetradentate ligands (E = B, Si). We examine all possible mechanisms and identify the dominant pathways and the critical elementary steps that can be ratedetermining in the catalytic cycle of nitrogen fixation. We find that the catalytic mechanism depends on the applied ligand and that the distal pathway observed with E = B is the most favorable route regarding the catalytic performance. Our calculations also reveal the lack of thermodynamic driving force in the last steps of the catalytic cycle that can be responsible for the low catalytic activity of the studied biomimetic catalysts. Our results can serve as a starting point for the rational design of biomimetic complexes, which should focus on establishing a steadily decreasing Gibbs free energy profile, as suggested by the Sabatier principle