Chemistry-A European Journal Scheme2.Synthesis of cAAC-supported dimeric [((Cy-cAAC)P-K) 2 (THF) 4 (2a)] and hexameric [((Cy-cAAC)P-K) 6 (THF) 2 (3)] potassium-phosphinidenides. Scheme3.Syntheses of tetrameric [((Me 2-cAAC)P-K) 4 (THF) 4 (4)] potassiumand trimeric [((Cy-cAAC)P-Na) 3 (THF) (5)] sodium-phosphinidenides.

A Schiff-base nickel­(II)-phosphene-catalyzed chemodivergent C–H functionalization and cyclopropanation of aromatic heterocycles is reported in moderate to excellent yields and very good regioselectivity and diastereoselectivity. The weak, noncovalent interaction between the phosphene ligand and Ni center facilitates the ligand dissociation, generating the electronically and coordinatively unsaturated active catalyst. The proposed mechanisms for the reported reactions are in good accord with the experimental results and theoretical calculations, providing a suitable model of stereocontrol for the cyclopropanation reaction.

This work describes employment of two structurally similar Schiff‐base ligands (H2L and H2L‐Me) [H2L = C14H13NO3 and H2L‐Me = C15H15NO3] for the synthesis of three homo‐metallic ZnII and two hetero‐bimetallic ZnII–NiII based multinuclear complexes {[ZnII4L4(MeOH)2] (1), [ZnII5(L)5(MeOH)2]·MeOH·CH3CN (2), [(L)2ZnII4Cl2(µ3‐OMe)2(MeOH)2]·2MeOH (3), [NiII2ZnII2(L)4(MeOH)2] (4) and [Ni3Zn2(L‐Me)5(H2O)2]·MeOH·CH3CN (5)} with different interesting structural core topologies. All of these complexes (1–5) have been characterized by single‐crystal X‐ray diffraction (XRD), elemental analysis, and UV/Vis and Fourier transform infrared (FTIR) spectroscopy. The fluorescence properties of ZnII‐containing complexes have been studied by measuring fluorescence spectra in solid state and solution phase. The luminescence behavior has been further quantified by fluorescence life‐time and quantum yield measurements. Using high resolution mass spectrometry (HR‐MS), the molecular integrity of complexes in the solution phase has been demonstrated by simulating isotopic distribution of molecules with theoretically calculated molecular isotopic patterns. The magnetic properties of ZnII–NiII containing complexes (4–5) have been studied in the temperature range from 5 K to 300 K. Thermogravimetric analysis (TGA) has been carried out to study the thermal stabilities of these complexes (1–5).

Alkyl substituted triaryl-cyclopentadienyl ligands with aggregation-induced emission enhancement (AIEE) properties and their applications in the syntheses of novel chloride bridged tetra-nuclear mixed potassium–dysprosium metallocenes.

Two new series of air stable compounds of cAACX = fluorene/indene (X = Me2, Et2, Cy) [cAAC = cyclic (alkyl) amino carbene] have been isolated and well characterized by X‐ray single crystal diffraction, photoluminescence, cyclic voltammogram (CV) and electron paramagnetic resonance (EPR) studies. Fluorescence studies reveals green light emission of cAAC bonded fluorene, whereas free fluorene generally displays a violet emission. Interestingly, the sterically crowded cAAC‐fluorene analogue display solvatochromism and CF3CO2H sensing in solution. CV of the these compounds show a quasi‐reversible electron transfer process, indicating the functionalization of fluorene/indene with radical anionic form of carbene, confirmed by CV/EPR measurements. DFT/TDDFT calculations and energy decomposition analysis coupled with natural orbital for chemical valence (EDA‐NOCV) have been carried out to study different aspects of bonding and electronic transitions. Such a class of redox active and thermally stable organic molecules may be suitable for molecule based spin memory devices in future.

A series of mixed valence hexanuclear dicationic coordination clusters containing two µ4‐O2– bridges with general formula M2+(X–)2 [M = CeIV2CeIII4(µ4‐O)2(L–R)4(val)6(H2O)2; 12+, 32+: R = H, 22+: Me; 12+, 22+: X = CeIII2(val)3(NO3)4, 32+: X = NO3] were synthesized, isolated and characterized. The reaction of cerium(III)nitrate hexahydrate with Schiff base ligand (H2L–R) and o‐vanillin (val‐H) under basic condition led to the formation of M2+(X–)2 and the reaction progress was monitored by mass spectrometric studies. The molecular structures of all complexes were unambiguously characterized by single‐crystal X‐ray diffraction. The magnetic susceptibility measurements of M2+(X–)2 showed that the Ce(III) ions are weakly antiferromagnetically coupled. Thermal stability and molar conductivity of M2+(X–)2 were also studied. Complex 32+(X–)2 was further studied by X‐ray photoelectron spectroscopy to confirm the oxidation states of Ce(III/IV) ions. The M2+ cation was shown to catalyze the TEMPO‐free oxidation of functionalized benzyl alcohols quantitatively to the corresponding benzaldehyde derivatives at 100 °C in presence of aerial O2 using DMF as the solvent.

A representative Co(II) based single ion magnet (SIM) with N 2 O 2 donor set and distorted pseudo-tetrahedral geometry has been synthesized and characterized to study the atomic and electronic structure. DC magnetometry results have been evaluated by means of a phenomenological Hamiltonian approach regarding zero field splitting (ZFS) parameters and compared with results from ab-initio multi-reference CASSCF (complete active space self-consistent field) calculations and qualitative ligand field theory (AILFT). Profound investigation of spin-lattice relaxation with the variation of temperature (from 1.8 to about 8 K) and magnetic field (at 14 different fields from zero up to 1 T) have been performed based on AC magnetometry. Under an applied dc magnetic field, spin-lattice relaxation occurs via a direct process with T 2 temperature dependence due to limited heat transfer at very low temperature and above 5 K relaxation by an Orbach process with an energy barrier of U eff � 80 K dominates.

Alkali metal salts of carbene‐supported phosphinidenides were obtained by the reductive dehalogenation of carbene‐stabilized chloro‐phosphinidene precursors in THF. Structural elucidations in solution and solid state reveals the existence of the dimeric phosphinidenide anions exclusively in THF solution, whereas in the solid state oligomerization takes place affording the corresponding highly reactive trimer, tetramer and hexamer depending upon the steric bulk of the stabilizing ligands and nature of the alkali metal ions. For more information, see the Communication by K. C. Mondal, S. Roy, et al. on page 200.