A versatile and rapid access to various chain lengths of ethylene-bridged BODIPY motifs was discovered. Corresponding oligomers comprising up to eight monomeric units were studied with respect to their microstructures by photophysical, X-ray crystallographic, and computational means. The investigation of three different dipyrrin cores revealed a crucial dependence on the substitution pattern of the core, whereas the nature of the meso-periphery is less critical. The impact of substituent effects on the conformational space was investigated by Monte Carlo simulations and a set of DFT methods (B3LYP, PBEh-3c, TPSS/PWPB95), including dispersion effects. Cryptopyrrole-derived oligo-BODIPYs are characterized by a tight intramolecular arrangement triggering a dominant J-type excitonic coupling with red-shifts up to 45 nm, exceptionally small line widths of the absorption and emission event (up to 286 cm), outstandingly high attenuation coefficients (up to 1 042 000 M cm), and quantum yields of up to unity.

Several pnictogen dihalide complexes of the type (WCA‐IDipp)EX2 (E=P, As, Sb; X=Cl, Br) that bear an anionic N‐heterocyclic carbene ligand with a weakly coordinating borate moiety (WCA‐IDipp, WCA=B(C6F5)3, IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) were prepared by salt metathesis reactions between the respective pnictogen trihalides EX3 and the lithium salt (WCA‐IDipp)Li⋅toluene. Two‐electron reduction of the dihalides (WCA‐IDipp)EX2 with 1,3‐bis(trimethylsilyl)‐1,4‐dihydropyrazine or elemental magnesium afforded the dipnictenes (WCA‐IDipp)2E2, which display typical element‐element double bonds as observed in diaryldiphosphenes, ‐arsenes and ‐stibenes. To provide an insight into the factors contributing to the structural stability of the pnictogen dihalide and dipnictene compounds, quantum chemical calculations were performed at the domain‐based local pair natural orbital coupled‐cluster (DLPNO‐CCSD(T)) level. A local energy decomposition (LED) analysis of the interaction between the carbene and the pnictogen dihalide or dipnictene moiety demonstrates that London dispersion is an essential factor for the stabilization of these compounds.

Several group 16 adducts of the type [(WCA-IDipp)E]Li(solv.) that bear an anionic N-heterocyclic carbene ligand with a weakly coordinating borate moiety (WCA-IDipp, WCA = B(C6F5)3, IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene, E =...

A modular approach afforded heteroleptic arsaphosphene species supported by neutral and anionic N-heterocyclic carbenes.

A series of neutral iridium(I) complexes of the general type [(WCA−NHC)]IrL(COD)] (COD=1,5‐cyclooctadiene; L=phosphine, pyridine), bearing anionic N‐heterocyclic carbenes (WCA−NHC) with a weakly coordinating anionic (WCA) borate moiety, were prepared by addition of phosphines and pyridine to [(WCA−NHC)]Ir(COD)], in which the available coordination site is stabilized by intramolecular metal‐arene interaction (π‐face donation). The solvent and substrate scope of the neutral complexes as catalysts for H/D exchange was investigated, revealing their suitability for promoting efficient deuteration in nonpolar solvents such as cyclohexane.

Anionic N-heterocyclic carbenes with weakly coordinating borate, aluminate, and gallate moieties of the type [(F 5 C 6 ) 3 E-NHC] − (E = B, Al, Ga) were isolated as lithium salts by the lithiation of 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (IMes) or 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene (IDipp) followed by the addition of E(C 6 F 5 ) 3 (E = B, Al, Ga). Treatment with elemental selenium afforded the lithium salts of the corresponding anionic selenourea derivatives [{(F 5 C 6 ) 3 E-NHC}Se] − (NHC = IMes, E = B; NHC = IDipp, E = B, Al, Ga), which were examined, among other things, by means of 77 Se{ 1 H} NMR spectroscopy to assess the π-accepting properties of the WCA-NHC ligands in comparison with their neutral NHC congeners.

Anionic N‐heterocyclic carbenes that bear a weakly coordinating fluoroborate moiety have been used to prepare a new class of anionic imidazolin‐2‐thione and ‐selone ligands; their coordination chemistry towards rhodium and iridium was explored to reveal their ability to develop secondary arene–metal interactions with the “wings” of the carbene ligands. More information about these new additions to the family of chalcogenolate ligands and their potential future application in coordination chemistry, bioinorganic chemistry and homogeneous catalysis can be found in the Research Article by M. Tamm et al. (DOI: 10.1002/chem.202104139).

A series of symmetric and asymmetric tetraaminocyclopentadienone iron tricarbonyl complexes were prepared from Fe­(CO)5 and the diaminoacetylenes (DAA) R2NCCNR2 (NR2 = piperidinyl, 4-methylpiperidinyl, homopiperidinyl) via intermediate ferracyclobutenone complexes. In the presence of trimethylamine-N-oxide, the reactions with acetonitrile afforded the corresponding iron dicarbonyl acetonitrile complexes, which served as highly active precatalysts for the transfer hydrogenation of aldehydes, ketones, and imines with isopropanol as the hydrogen source and for the hydrogenation of aldehydes and ketones with dihydrogen under comparatively mild reaction conditions (3 bar H2 pressure, room temperature). Density functional theory (DFT) calculations were performed to reveal the mechanism of the isopropanol-mediated transfer hydrogenation of benzaldehyde and acetophenone, which is likely to involve a catalytically active hydroxycyclopentadienyl iron dicarbonyl hydride species. Dihydrogen transfer from the latter onto benzaldehyde and acetophenone occurs in a concerted manner with exceptionally low activation barriers following the established outer-sphere mechanism.