Frontispiece: An Octanuclear Metallosupramolecular Cage Designed To Exhibit Spin-Crossover Behavior

Ein achtkerniger metallosupramolekularer Würfel mit Spin-Crossover-Eigenschaften

Enantiomerenreine [M6L12]- oder [M12L24]-Polyeder aus flexiblen Bis(pyridin)-Liganden

Electron Energy Loss and DFT/SCI Study of the Singlet and Triplet Excited States of Aminobenzonitriles and Benzoquinuclidines:  Role of the Amino Group Twist Angle

Spectroscopic consequences of varying the twist angle of the amino group in aminobenzonitrile systems in the electronic ground state are investigated by applying electron energy loss (EEL) spectroscopy and density functional theory to 4-N,N-dimethylaminobenzonitrile (DMABN), 4-N,N-dimethylamino-3,5-dimethylbenzonitrile (MMD), benzoquinuclidine (BQ), and 6-cyanobenzoquinuclidine (CBQ). A number of singlet and triplet excited states was observed and assigned with the help of DFT/SCI theory. The results characterize the gas-phase spectroscopy of the molecules and verify to within 0.3 eV the predictive power of DFT/SCI theory for vertical states over a wide range of twist and pyramidalization a…

Enantiomerically pure [M(6)L(12)] or [M(12)L(24)] polyhedra from flexible bis(pyridine) ligands.

Coordination-driven self-assembly is one of the most powerful strategies to prepare nanometer-sized discrete (supra)molecular assemblies. Herein, we report on the use of two constitutionally isomeric BINOL-based bis(pyridine) ligands for this purpose. Upon coordination to Pd(II) ions these self-assemble into enantiomerically pure endo- and exo-functionalized hexa- and dodecanuclear metallosupramolecular spheres with a chiral skeleton depending on the substitution pattern of the BINOL core. These aggregates were characterized by NMR, MS, DLS, TEM, and EELS as well as ECD. Furthermore, experimental ECD data could be compared to those obtained from theoretical simulations using a simplified Ta…

Enantiomerically pure trinuclear helicates via diastereoselective self-assembly and characterization of their redox chemistry.

A tris(bipyridine) ligand 1 with two BINOL (BINOL = 2, 2′-dihydroxy-1, 1′-binaphthyl) groups has been prepared in two enantiomerically pure forms. This ligand undergoes completely diastereoselective self-assembly into D2-symmeteric double-stranded trinuclear helicates upon coordination to copper(I) and silver(I) ions and to D3-symmetric triple-stranded trinuclear helicates upon coordination to copper(II), zinc(II), and iron(II) ions as demonstrated by mass spectrometry, NMR and CD spectroscopy in combination with quantum chemical calculations and X-ray diffraction analysis. According to the calculations, the single diastereomers that are formed during the self-assembly process are strongly …

Exploration of the Solid-State Sorption Properties of Shape-Persistent Macrocyclic Nanocarbons as Bulk Materials and Small Aggregates.

Porous molecular materials combine benefits such as convenient processability and the possibility for atom-precise structural fine-tuning which makes them remarkable candidates for specialty applications in the areas of gas separation, catalysis, and sensing. In order to realize the full potential of these materials and guide future molecular design, knowledge of the transition from molecular properties into materials behavior is essential. In this work, the class of compounds termed cycloparaphenylenes (CPPs)-shape-persistent macrocycles with built-in cavities and radially oriented π-systems-was selected as a conceptually simple class of intrinsically porous nanocarbons to serve as a platf…

Influencing the Self‐Sorting Behavior of [2.2]Paracyclophane‐Based Ligands by Introducing Isostructural Binding Motifs

Abstract Two isostructural ligands with either nitrile (Lnit) or isonitrile (Liso) moieties directly connected to a [2.2]paracyclophane backbone with pseudo‐meta substitution pattern have been synthesized. The ligand itself (Lnit) or its precursors (Liso) were resolved by HPLC on a chiral stationary phase and the absolute configuration of the isolated enantiomers was assigned by XRD analysis and/or by comparison of quantum‐chemical simulated and experimental electronic circular dichroism (ECD) spectra. Surprisingly, the resulting metallosupramolecular aggregates formed in solution upon coordination of [(dppp)Pd(OTf)2] differ in their composition: whereas Lnit forms dinuclear complexes, Liso…

An Octanuclear Metallosupramolecular Cage Designed To Exhibit Spin-Crossover Behavior.

By employing the subcomponent self-assembly approach utilizing 5,10,15,20-tetrakis(4-aminophenyl)porphyrin or its zinc(II) complex, 1H-4-imidazolecarbaldehyde, and either zinc(II) or iron(II) salts, we were able to prepare O-symmetric cages having a confined volume of ca. 1300 Å3 . The use of iron(II) salts yielded coordination cages in the high-spin state at room temperature, manifesting spin-crossover in solution at low temperatures, whereas corresponding zinc(II) salts led to the corresponding diamagnetic analogues. The new cages were characterized by synchrotron X-ray crystallography, high-resolution mass spectrometry, and NMR, Mössbauer, IR, and UV/Vis spectroscopy. The cage structures…

Influencing the self‐sorting behavior of [2.2]paracyclophane based ligands by introducing isostructural binding motifs

Two isostructural ligands with either nitrile ( L nit ) or isonitrile ( L iso ) moieties directly connected to a [2.2]paracyclophane backbone with pseudo‐meta substitution pattern have been synthesized. The ligand itself ( L nit ) or its precursors ( L iso ) were resolved via HPLC on a chiral stationary phase and the absolute configuration of the isolated enantiomers was assigned by XRD analysis and/or by comparison of quantum‐chemical simulated and experimental ECD‐spectra. Surprisingly, the resulting metallosupramolecular aggregates formed in solution upon coordination of [(dppp)Pd(OTf) 2 ] differ in their composition: whereas L nit forms dinuclear complexes L iso exclusively forms trinuc…

CCDC 1961176: Experimental Crystal Structure Determination

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CCDC 1451726: Experimental Crystal Structure Determination

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CCDC 1824417: Experimental Crystal Structure Determination

Related Article: Lucia Volbach, Niklas Struch, Fabian Bohle, Filip Topić, Gregor Schnakenburg, Andreas Schneider, Kari Rissanen, Stefan Grimme, Arne Lützen|2020|Chem.-Eur.J.|26|3335|doi:10.1002/chem.201905070

CCDC 1824416: Experimental Crystal Structure Determination

Related Article: Lucia Volbach, Niklas Struch, Fabian Bohle, Filip Topić, Gregor Schnakenburg, Andreas Schneider, Kari Rissanen, Stefan Grimme, Arne Lützen|2020|Chem.-Eur.J.|26|3335|doi:10.1002/chem.201905070

CCDC 1955599: Experimental Crystal Structure Determination

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CCDC 1003004: Experimental Crystal Structure Determination

Related Article: Christoph Gütz , Rainer Hovorka , Niklas Struch , Jens Bunzen , Georg Meyer-Eppler , Zheng-Wang Qu , Stefan Grimme , Filip Topić, Kari Rissanen, Mario Cetina, Marianne Engeser, Arne Lützen|2014|J.Am.Chem.Soc.|136|11830|doi:10.1021/ja506327c

CCDC 1961177: Experimental Crystal Structure Determination

Related Article: Tobias A. Schaub, Ephraim A. Prantl, Julia Kohn, Markus Bursch, Checkers R. Marshall, Erik J. Leonhardt, Terri C. Lovell, Lev N. Zakharov, Carl K. Brozek, Siegfried R. Waldvogel, Stefan Grimme, Ramesh Jasti|2020|J.Am.Chem.Soc.|142|8763|doi:10.1021/jacs.0c01117

CCDC 1955601: Experimental Crystal Structure Determination

Related Article: Lucia Volbach, Niklas Struch, Fabian Bohle, Filip Topić, Gregor Schnakenburg, Andreas Schneider, Kari Rissanen, Stefan Grimme, Arne Lützen|2020|Chem.-Eur.J.|26|3335|doi:10.1002/chem.201905070

CCDC 1961179: Experimental Crystal Structure Determination

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CCDC 1955600: Experimental Crystal Structure Determination

Related Article: Lucia Volbach, Niklas Struch, Fabian Bohle, Filip Topić, Gregor Schnakenburg, Andreas Schneider, Kari Rissanen, Stefan Grimme, Arne Lützen|2020|Chem.-Eur.J.|26|3335|doi:10.1002/chem.201905070