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Three different dipyridyl ligands were combined with [Pd(CH3CN)4](BF4)2 to give mixtures of homo- and/or heteroleptic coordination cages. The three ligands were chosen so that one ligand shows a parallel orientation of the coordinate vectors, the second ligand a bent angle of 60°, and the third ligand a bent angle of 120°. We have identified ligand mixtures that give rise to integrative self-sorting, and we have characterized a heterotrileptic [Pd4L2L′2L′′4]8+ cage by single crystal X-ray crystallography. The structural flexibility of ligands with alkynyl spacers was found to be of importance for the formation of heteroleptic complexes. [ABSTRACT FROM AUTHOR]

The isomerization of iridium(III) complexes with metalated N-heterocyclic carbene (NHC) ligands was studied. The fac isomers of complexes with 1-phenyl-3-methylbenzimidazolin-2-ylidene or 1-phenyl-3-benzylbenzimidazolin-2-ylidene ligands are transformed cleanly into the mer isomers when solutions of the complexes are treated with first HNTf2 and then NEt3. The transformation can be accomplished within a few minutes and the side product (NEt3H)(NTf2) is easy to separate. Spectroscopic and structural analyses indicate that the isomerization proceeds by protonation of the carbene ligand at the metalated phenyl group, accompanied by a fac → mer rearrangement of the carbene donors. An iridium complex with a 1-phenyl-1,2,4-triazolo[4,3-f]phenanthridine-based carbene ligand could not be isomerized under similar conditions, most likely because of its reduced conformational flexibility. [ABSTRACT FROM AUTHOR]

The quest for lead-free light-absorbing perovskite materials has long been the target of researchers to make the 'star' material friendly to the commercial market. After a summary of different lead-free solar absorbers, we demonstrate a zero-dimensional iodobismuthate (MA)3[BiI6]·3MACl (MA: CH3NH3) featuring isolated hexaiodobismuthate(III) anions in the crystal analysis. The unexpectedly formed material was made via an orthogonal solvent permeation method and the decomposition of the guest solvent. We compare the BiI63− containing compound with a series of more common iodobismuthates, especially the dinuclear Bi2I93− in terms of dimensionalities via single-crystal diffraction and DFT calculations, respectively. An undocumented second-order phase transition was found between 190 K and 160 K for the dimeric MA3Bi2I9. The photovoltaic device from a thermally reorganized polycrystalline film of (MA)3[BiI6]·3MACl, which resembled the structure of (MA)3[Bi2I9] gave a power conversion efficiency of 1.09%. [ABSTRACT FROM AUTHOR]

The synthetic utility of triazenes rests on the fact that the triazene function can be cleaved by Brønsted or Lewis acids, liberating diazonium compounds. However, the preferred coordination site of the acid is still a matter of debate. We have analyzed triflic acid, B(C6F5)3, and PdCl2 adducts of triazenes by NMR spectroscopy and single crystal X-ray crystallography. In all cases, we observe coordination of the acid to the N1 atom of the triazene. This finding is not only of relevance for acid-induced cleavage reactions, but also for metal-catalyzed reactions with triazenes, which are increasingly being used in synthetic organic chemistry. [ABSTRACT FROM AUTHOR]

Two dinuclear homoleptic complexes of lanthanides(ii) supported by the polydentate tris(tertbutoxy) siloxide ligand ([Yb2L4], 1-Yb and [Sm2L4], 1-Sm, (L = (OtBu)3SiO−)) were synthesized in 70–80% yield and 1-Sm was crystallographically characterized. 1-Yb and 1-Sm are stable in solution at −40 °C but cleave the DME C–O bond over time at room temperature affording the crystal of [Yb2L4(μ-OMe)2(DME)2], 2. The 1-Yb and 1-Sm complexes effect the reduction of CO2 under ambient conditions leading to carbonate and oxalate formation. The selectivity of the reduction towards oxalate or carbonate changes depend on the solvent polarity and on the nature of the ion. For both the lanthanides, carbonate formation is favoured but oxalate formation increases if a non-polar solvent is used. Computational studies suggest that the formation of oxalate is favoured with respect to carbonate formation in the reaction of the dimeric lanthanide complexes with CO2. Crystals of the tetranuclear mixed-valence oxalate intermediate [Yb4L8(C2O4)], 3 were isolated from hexane and the presence of a C2O42− ligand bridging two [YbIIL2YbIIIL2] dinuclear moieties was shown. Crystals of the tetranuclear di-carbonate product [Sm4L8(μ3-CO3-κ4-O,O′,O′′)2], 4 were isolated from hexane. The structures of 3 and 4 suggest that the CO2 activation in non-polar solvents involves the interaction of two dimers with CO2 molecules at least to some extent. Such a cooperative interaction results in both oxalate and carbonate formation. [ABSTRACT FROM AUTHOR]

Microporous networks based on boronate ester-capped iron(ii) clathrochelate complexes are described. The networks were obtained by covalent cross-linking of tetrabrominated clathrochelate complexes via Suzuki–Miyaura polycross-coupling reactions with diboronic acids, or by Sonogashira–Hagihara polycross-coupling of clathrochelate complexes with terminal alkyne functions and 1,3,5-tribromobenzene. The networks display permanent porosity with apparent Brunauer–Emmett–Teller surface areas of up to SABET = 593 m2 g−1. A clathrochelate complex based on an enantiopure dioximato ligand was used to prepare chiral networks. One of these networks was shown to preferentially absorb d-tryptophan over l-tryptophan. [ABSTRACT FROM AUTHOR]