Facile High-Yield Synthesis of Pure, Crystalline Mg(BH₄)₂

Magnesium borohydride, Mg(BH4)2, a long-sought candidate for efficient hydrogen storage chemisorption technology, has been obtained in a pure and crystalline form by two new synthetic routes in a hydrocarbon solvent. A first synthetic approach involves a metathetical reaction between organometallic magnesium compounds; a second route consists of an insertion reaction of BH3 species, released from BH3·S(CH3)2, into the Mg−C bonds of MgR2, with complete replacement of R groups with BH4 groups. Both methods, based on commercially available reagents, afford identical, pure, polycrystalline materials, identified by X-ray diffraction as the so-called low-temperature hexagonal form of Mg(BH4)2, stable below 180 °C, recently shown to possess a complex, unpredictable, crystal structure

Synthesis and Characterization of the First Mononuclear Ni^II Phosphorane Imino Complex

Synthesis and Characterization of the First Mononuclear NiII Phosphorane Imino Comple

Synthesis and Characterization of the First Mononuclear Ni^II Phosphorane Imino Complex

Synthesis and Characterization of the First Mononuclear NiII Phosphorane Imino Comple

Designing Molecules for Metal−Metal Electronic Communication: Synthesis and Molecular Structure of the Couple of Heterobimetallic Isomers [η⁶-(2-Ferrocenyl)indene]-Cr(CO)₃ and [η⁶-(3-Ferrocenyl)indene]-Cr(CO)₃

The heterobinuclear isomers [η6-(2-ferrocenyl)indene]-Cr(CO)3 (1) and [η6-(3-ferrocenyl)indene-Cr(CO)3 (2) have been prepared and the crystal structure determination showed that the Fe(C5H5) and Cr(CO)3 groups in the two molecules are disposed in different conformations with respect to the Cp-indene bridging ligand, cisoid in 1 and transoid in 2. Preliminary electrochemical (CV) and spectroscopic (IR and near-IR) results obtained for the corresponding monooxidized 1+ and 2+ demonstrate the existence of stronger electronic coupling in 1+ than in 2+

Mixed Valence Properties in Ferrocenyl-Based Bimetallic FeCp−Indenyl−ML_<i>n</i> Complexes: Effect of the ML_<i>n</i> Group

A series of ferrocenyl-based complexes of general structure [η5-(2-ferrocenyl)indenyl]MLn [MLn = RuCp*, FeCp, IrCOD, Mn(CO)3, and Cr(CO)2NO] were synthesized with the aim of tuning the effect of the nature of the second metal group MLn on the magnitude of the metal−metal electronic coupling in their mixed valence ions generated by electrochemical oxidation. The electronic interaction was probed by determining different and independent physical properties, the potential splitting in the cyclic voltammograms, and the IT bands in the near-IR spectra, which were rationalized in the framework of Marcus−Hush theory and at the quantum chemistry level by the density functional theory and TD density functional theory methods. On the basis of the obtained results, we were able to establish a trend based on the magnitude of the Fe−M electron transfer parameters Hab and α ranging from weakly to moderately coupled mixed valence ions

Designing Molecules for Metal−Metal Electronic Communication: Synthesis and Molecular Structure of the Couple of Heterobimetallic Isomers [η⁶-(2-Ferrocenyl)indene]-Cr(CO)₃ and [η⁶-(3-Ferrocenyl)indene]-Cr(CO)₃

The heterobinuclear isomers [η6-(2-ferrocenyl)indene]-Cr(CO)3 (1) and [η6-(3-ferrocenyl)indene-Cr(CO)3 (2) have been prepared and the crystal structure determination showed that the Fe(C5H5) and Cr(CO)3 groups in the two molecules are disposed in different conformations with respect to the Cp-indene bridging ligand, cisoid in 1 and transoid in 2. Preliminary electrochemical (CV) and spectroscopic (IR and near-IR) results obtained for the corresponding monooxidized 1+ and 2+ demonstrate the existence of stronger electronic coupling in 1+ than in 2+

Mixed Valence Properties in Ferrocenyl-Based Bimetallic FeCp−Indenyl−ML_<i>n</i> Complexes: Effect of the ML_<i>n</i> Group

A series of ferrocenyl-based complexes of general structure [η5-(2-ferrocenyl)indenyl]MLn [MLn = RuCp*, FeCp, IrCOD, Mn(CO)3, and Cr(CO)2NO] were synthesized with the aim of tuning the effect of the nature of the second metal group MLn on the magnitude of the metal−metal electronic coupling in their mixed valence ions generated by electrochemical oxidation. The electronic interaction was probed by determining different and independent physical properties, the potential splitting in the cyclic voltammograms, and the IT bands in the near-IR spectra, which were rationalized in the framework of Marcus−Hush theory and at the quantum chemistry level by the density functional theory and TD density functional theory methods. On the basis of the obtained results, we were able to establish a trend based on the magnitude of the Fe−M electron transfer parameters Hab and α ranging from weakly to moderately coupled mixed valence ions

Heterobimetallic (Ferrocenyl)indenyl Rhodium Complexes. Synthesis, Crystal Structure, and Oxidative Activation of [η⁵-(1-Ferrocenyl)indenyl]RhL₂ [L₂ = COD, NBD, (CO)₂]^‖

The binuclear [η5-(1-ferrocenyl)indenyl]Rh(NBD) (1), [η5-(1-ferrocenyl)indenyl]Rh(COD) (1a), and [η5-(1-ferrocenyl)indenyl]Rh(CO)2 (2) complexes have been synthesized (NBD = norbornadiene; COD = cycloocta-1,5-diene). The crystal structure determination showed that the iron and rhodium nuclei are disposed in a transoid configuration in 1 probably to avoid steric repulsions. On the contrary, in 2 the metals are in a cisoid configuration due to the presence of stabilizing π-hydrogen bonds between the CO's and the hydrogens of the unsubstituted cyclopentadienyl ring. The results of the chemical and electrochemical oxidation of 2 are in favor of the existence of an effective interaction between the two metals

New η²-Formamidinyl Zirconium Complexes: Synthesis, Characterization, and Catalytic Activity

The new η2-formamidinyl Zr complex (1) (Ar = 2,6-dimethylphenyl, Cyc = cyclohexyl) was prepared upon double insertion of 2,6-dimethyl phenyl isocyanide in the Zr−N bond of Zr(NMeCyc)4. 1 was then converted into (2) and (3) by reacting it with C6F5OH and [NHMe3]Cl, respectively. The crystal structure of 1 was established by X-ray analysis. All the complexes have been tested as catalysts for the polymerization of ethylene and 1-hexene in the presence of [NHMe2Ph][B(C6F5)4] as cocatalyst

Charge Transfer through Isomeric Unsaturated Hydrocarbons. Redox Switchable Optical Properties and Electronic Structure of Substituted Indenes with a Pendant Ferrocenyl

A family of (ferrocenyl)indenes, (2-ferrocenyl)indene, (2-ferrocenyl)tetramethylindene, (2-ferrocenyl)hexamethylindene, (3-ferrocenyl)indene, and (3-ferrocenyl)hexamethylindene, and the corresponding monooxidized cations have been prepared. The results of a structural and spectroelectrochemical study are discussed. The availability of pairs of isomers with known geometries and differently methylated indenes allowed the detailed investigation of how slight geometric and electronic modifications affect their physical properties. The molecular structures have been determined by X-ray diffraction and compared with the fully optimized structures calculated with state-of-the-art DFT methods. Calculated and crystallographic structures agree in establishing the dependence of the orientation of the indene moiety and the ferrocenyl cyclopentadienyl rings on the degree of methylation. The UV−vis spectra and in particular the appearance upon oxidation of a new near-IR absorption, whose energy and intensity increase with the degree of methylation and cyclopentadienyl-indene planarity, are rationalized in the framework of the Hush theory and at quantum chemistry level by DFT and TD-DFT calculations