Carbenes, a class of low-valent group 14 ligand, have shifted the paradigm in our understanding of the effects of supporting ligands in transition-metal reactivity and catalysis. We now seek to...

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.

We describe facile synthetic methods for accessing linear cationic tetrylene nickel(0) complexes [SiiPDippE·Ni(PPh3)3]+ (E = Ge (4) and Sn (5); SiiPDipp = [(iPr3Si)(Dipp)N]-), which feature dative E-Ni triple bonds. These...

A series of new Ruthenium(II) complexes based on the (1,10phenanthrolin-5-yl)diethyl phosphonate ligand L2 and their corresponding phosphonic acid along with reference compounds are synthesized in order to evaluate the influence of the phosphonate substitution on the catalytic performance of such molecules. UV-vis absorption and emission spectroscopy show, that introduction of a phosphonate moiety into the periphery of the phenanthroline ligand does not alter the photophysical properties of the complex. In contrast, the electrochemical features of all compounds are affected upon respective functionalization compared to the reference molecule [Ru(bpy) 3 ](PF 6 ) 2 in aqueous medium. Photostability tests in water or in water/persulfate show a dependency of the stability towards photodecomposition on quenching efficiency with persulfate anion. The lower quenching efficiency thus leads to increased stability based on the negative charge of the phosphonate moiety in 2 and P1 in aqueous medium following a quenching efficiency trend of [Ru(bpy) 3 ](PF 6 ) 2 > 1 > 2 > P1. Photocatalytic water oxidation using [Ru(dpp)(pic) 2 ](PF 6 ) 2 reveals that compound 1 and [Ru(bpy) 3 ](PF 6 ) 2 doe not exhibit any activity under the utilized conditions, P1 shows a negligible TON of 7, whereas compound 2 reaches a TON of 140 after 1 h. This fact highlights that the redox potential is not the sole driver in the catalytic cycle and accentuates the importance of different criteria determining the suitability of photosensitizers in light-driven water oxidation, such as light absorption, redox potential of the Ru III /Ru II event, photostability towards and quenching efficiency with the sacrificial agent.

A novel non‐innocent ligand class, namely cationic single‐centre ambiphiles, is reported in the phosphine‐functionalised cationic tetrylene Ni0 complexes, [PhRDippENi(PPh3)3]+ (4 a/b (Ge) and 5 (Sn); PhRDipp={[Ph2PCH2SiR2](Dipp)N}−; R=Ph, iPr; Dipp=2,6‐iPr2C6H3). The inherent electronic nature of low‐coordinate tetryliumylidenes, combined with the geometrically constrained [N−E−Ni] bending angle enforced by the chelating phosphine arm in these complexes, leads to strongly electrophilic EII centres which readily bind nucleophiles, reversibly in the case of NH3. Further, the GeII centre in 4 a/b readily abstracts the fluoride ion from [SbF6]− to form the fluoro‐germylene complex PhRDippGe(F)Ni(PPh3)3 9, despite this GeII centre simultaneously being a σ‐donating ligand towards Ni0. Alongside the observed catalytic ability of 4 and 5 in the hydrosilylation of alkynes and alkenes, this forms an exciting introduction to a multi‐talented ligand class in cationic single‐centre ambiphiles.