Nickel, palladium, and copper complexes of the tripyrrolic ligand hexaethyltripyrrindione (H 3 Et 6 tpd, 1) have been prepared and characterized by UV/Vis and EPR spectroscopy, as well as by single-crystal X-ray structure determination. In all cases the metal ion is coordinated in a distorted square-planar geometry carrying a water ligand at the fourth coordination site. The Et 6 tpd ligand acts as a radical dianion in all cases. In solution, monomeric species are present in which the open-

Five metal complexes of 10,10-dimethylisocorrole ligands with full -pyrrolic substitution is have been synthesized. The preparation of nickel(II), palladium(II), and copper(II) complexes was achieved by metal-templated oxidative macrocyclization of tetrapyrrolic 5,15-biladiene precursors. The reaction conditions for successful macrocycle formation in yields of 18-32 % depended strongly on the type of metal ion used. In the case of palladium, three different macrocyclic products were observed by varying the cyclization protocol. The ring-con- [a] 3077 Scheme 1. Preparation of 10,10-dimethylbiladienes 1 and 2 as hydroperchlorate salts. Reagents and conditions: a) HClO 4 (68 %), methanol.

Invited for the cover of this issue is the group of Martin Bröring from the Technical University Braunschweig, Germany. The cover image shows the metal‐ion‐templated macrocyclization of linear tetrapyrroles for the synthesis of non‐aromatic porphyrinoids.

The condensation of aldehydes with BODIPY (boron dipyrrin) luminophores was investigated. Formaldehyde can be used to connect two BODIPYs at each of the three pyrrolic C positions (α-, β-, and β'-positions) in a quick and highly selective manner, yielding new DYEmers (di- and oligomeric BODIPY derivatives) with varied photophysical properties. Benzaldehydes form DYEmers only at the β- and the β'-positions. For aliphatic aldehydes the DYEmer formation competes with the elimination of water from a proposed alcohol intermediate, leading to the formation of α- and β-alkenyl-BODIPYs. 2-Phenylacetaldehyde and similar precursors exclusively yield elimination products. These acid-mediated transformations are valuable alternatives to the well-established, base-promoted Knoevenagel condensation protocol that is typically employed in the preparation of BODIPYs with near infrared (NIR)-shifted absorptions.

10-Heterocorrole complexes with oxygen, sulfur, and selenium at position 10 of the macrocycle and with the divalent ions of nickel, copper, and palladium were prepared and investigated. The focus was set on the size adaptation and matching mechanisms of cavity size versus ionic radius in corrole-type macrocycles. A full set of single-crystal X-ray analytical data revealed that in all but one case the N binding site of the ring-contracted tetrapyrrole was larger than necessary to bind the metal ion without deformation. In-plane size adaptation through M-N bond-length elongation by 2.5-3.2 % was effective, as well as pronounced out-of-plane ruffling of the macrocycle for those compounds with a more severe size mismatch. Such ruffling had been excluded for corroles previously, but is apparently the most efficient mechanism to adapt to small central ions.

10‐Heterocorrole complexes with oxygen, sulfur, and selenium at position 10 of the macrocycle and with the divalent ions of nickel, copper, and palladium were prepared and investigated. The focus was set on the size adaptation and matching mechanisms of cavity size versus ionic radius in corrole‐type macrocycles. A full set of single‐crystal X‐ray analytical data revealed that in all but one case the N4 binding site of the ring‐contracted tetrapyrrole was larger than necessary to bind the metal ion without deformation. In‐plane size adaptation through M−N bond‐length elongation by 2.5–3.2 % was effective, as well as pronounced out‐of‐plane ruffling of the macrocycle for those compounds with a more severe size mismatch. Such ruffling had been excluded for corroles previously, but is apparently the most efficient mechanism to adapt to small central ions.

Synthetic routes following a sequential MacMillan organocatalytic asymmetric a-fluorination protocol for aldehydes and then reductive amination, has allowed ready access to bioactive b-fluoroamines. The approach is demonstrated with a short synthesis of (S)-3-fluoro-g-aminobutyric acid (3F-GABA) and was extended to b-fluoroamine stereoisomers of cinacalcet, tecalcet, fendilines and NPS R-467, all allosteric modulators of the calcium receptor (CaR). Stereoisomers of the fluorinated calcimimetic analogues were then assayed in a CaR receptor assay and a comparison of b-fluoroamine matched pair stereoisomers revealed a binding mode preference to the receptor as deduced from conformations which will be favoured as a consequence of the electrostatic gauche effect.

The cover picture shows, in a symbolized manner, the two elemental processes that occur during the metal‐templated macrocyclization of linear tetrapyrroles: the locking of a pseudomacrocyclic conformation and the induced cyclization by coupling of the tetrapyrrole termini. Isocorroles are new members of the porphyrinoid family that have been made accessible by this approach and are highlighted as love padlocks. Details are discussed in the article by M. Bröring et al. on http://onlinelibrary.wiley.com/doi/10.1002/ejic.201600419/abstract. For more on the story behind the cover research, see the http://onlinelibrary.wiley.com/doi/10.1002/ejic.201600419/full.