Regiospecific C–N Photocyclization of 2‑Styrylquinolines

Regiospecific C–N photocyclization of 2-styrylquinolines resulting in formation of potentially biologically active quino­[1,2-<i>a</i>]­quinolizinium derivatives was investigated. The presence of strong electron-donating groups in the phenyl ring reveals to be a crucial factor managing photocyclization effectiveness. Introduction of a crown ether moiety allows changing the photoreaction parameters by means of complexation with Mg­(ClO₄)₂

Distorted <i>commo</i>-Cobaltacarboranes Based on the 5,6-Dicarba-<i>nido</i>-decaborane(12): The First Bimetal Cobalt–Copper Zwitterion-Containing Cluster with Four (B–H)₄···Cu Bonds Not Showing Fluxional Behavior in Solution

Treatment of a recently reported complex [Ph₄P]­[<i>closo,nido-</i>CoH­(2,4-C₂B₈H₁₀)­(7,8-C₂B₈H₁₁)] (<b>1</b>) either by H₂O₂ in acetone or NaH in THF leads to the loss of both the bridging and terminal hydrides yielding the diamagnetic salt of an anionic <i>commo</i>-cobaltacarborane [Ph₄P]­[Co­(2,4-<i>isonido</i>-C₂B₈H₁₀)₂] (<b>2</b>) with the {CoC₂B₈}-cluster units adopting a distorted skeletal geometry of the <i>isonido</i>-type. The anionic <i>commo</i> complex <b>2</b> reacts with in situ generated cationic [CuPPh₃]⁺ species to give stable copper–cobalt zwitterion [Ph₃PCu]­[Co­(2,4-<i>isonido</i>-C₂B₈H₁₀)₂] (<b>3</b>) with four two-electron, three-center (B–H)₄···Cu bonds, and exhibits no fluxional behavior in solution. Complex <b>3</b>, at the same time, in CH₂Cl₂ in the presence of 2-fold excess of PPh₃ readily converts to a new anionic species [(Ph₃P)₃Cu]­[Co­(2,4-<i>isonido</i>-C₂B₈H₁₀)₂] (<b>4</b>) which retains initial <i>isonido</i> geometry. All newly obtained diamagnetic <i>commo</i> complexes were characterized by a combination of analytical and multinuclear NMR spectroscopic data and by single-crystal X-ray diffraction studies of complexes <b>2</b> and <b>3</b>

The Role of Weak Interactions in Strong Intermolecular M···Cl Complexes of Coinage Metal Pyrazolates: Spectroscopic and DFT Study

The nondestructive reversible complexation of the macrocyclic group 11 metal pyrazolates {[3,5-(CF₃)₂Pz]­M}₃ (M = Cu­(I), Ag­(I)) to the halogen atom X = Cl, Br of η³-allyliron tricarbonyl halides (η³-2-R-C₃H₄)­Fe­(CO)₃X is revealed by the variable-temperature spectroscopic (IR, NMR) study combined with density functional theory calculations. The composition of all complexes at room temperature is determined as 1:1. In the case of the [AgL]₃ macrocycle, complexes 1:2 are observed at low temperature (<260 K). The complex’s stability depends on the substituents in the allyl fragment and halide ligand as well as on the metal atom (Ag­(I), Cu­(I)) in the macrocycle. For bulky substituents (Me and Ph) the endo/exo equilibrium of the parent (η³-2-R-C₃H₄)­Fe­(CO)₃X shifts upon the complex formation in favor of the exo isomer due to additional noncovalent interactions of the substituent with macrocycle

Supramolecular Design of the Trinuclear Silver(I) and Copper(I) Metal Pyrazolates Complexes with Ruthenium Sandwich Compounds via Intermolecular Metal−π Interactions

The interaction of copper­(I) and silver­(I) macrocyclic pyrazolates with aromatic ligands of ruthenium sandwiches (Cp*RuInd, CpRuInd, and Ind₂Ru) in solution is shown for the first time. The similar mode of coordination of macrocycles to the C₆ fragment of indenyl ligand was found both in the solution and in the solid state. Complexation of macrocycles with the nonencumbered sandwiches (CpRuInd, Ind₂Ru) leads to the formation of infinite stacks via alternating molecules of macrocycles and sandwich compounds as one-dimensional coordination polymers with a regular structure. Coordination mode of the indenyl ligand is independent of the second part of the ruthenium sandwich as well as of the aromatic ligand coordinated to another face of the macrocycle. The general principle of macrocycle supramolecular packing suggests coordination of two ligands on both faces of the macrocycle