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New divalent lanthanoid and alkaline earth metal complexes bearing the 1,3‐bis(diphenylphosphano)cyclopentadienyl ligand have been synthesised using the redox‐transmetallation protolysis (RTP) approach. From the reaction of the corresponding metal, diphenylmercury and the proligand C5H4(PPh2)2, the compounds [M(η5‐C5H3(PPh2)2‐1,3)2(S)] (with M=Yb, S=(thf)2 or M=Yb, Eu, Ca, Sr, Ba, S=dme) were isolated and characterised by X‐ray diffraction and multinuclear NMR spectroscopy. These compounds may provide a platform for early‐late heterobimetallic complexes. [ABSTRACT FROM AUTHOR]

The theoretical structure and thermochemistry of the tetrameric, low-valence aluminum compound Al4Cp8 Ph 4 (Cp8 Ph = C5Me4Ph) is discussed. The first synthesis of this compound was reported in 2005, but the compound failed to crystallize and experimental 27Al NMR results were inconclusive in regard to the degree of association. Here density functional theory combined with a genetic algorithm is used to predict the expected structure and properties for Al4Cp8 Ph 4. Synthesis efforts were repeated for this compound, resulting in a product with a 27Al NMR chemical shift that differed from the previous report by nearly 20 ppm. However, calculated 27Al NMR chemical shifts for the theoretically predicted structure are within one ppm of these new experimental results, strongly suggesting the tetrameric form has been synthesized. Previous work on five Al4R4 (R = 5H5, C5Me4H, C5Me5, C5Me4iPr, C54Pr) compounds showed a general trend towards an increased likelihood of disassociation into monomeric species in solution as ligand bulk increased. Analysis of Al4Cp8 Ph 4, the sixth and bulkiest compound in this series, indicates a departure from this trend. Bonding characteristics for monomer and tetramer forms in this series are examined in detail via topological analysis to understand this trend. [ABSTRACT FROM AUTHOR]

The theoretical structure and thermochemistry of the tetrameric, low-valence aluminum compound Al4Cp8 Ph 4 (Cp8 Ph = C5Me4Ph) is discussed. The first synthesis of this compound was reported in 2005, but the compound failed to crystallize and experimental 27Al NMR results were inconclusive in regard to the degree of association. Here density functional theory combined with a genetic algorithm is used to predict the expected structure and properties for Al4Cp8 Ph 4. Synthesis efforts were repeated for this compound, resulting in a product with a 27Al NMR chemical shift that differed from the previous report by nearly 20 ppm. However, calculated 27Al NMR chemical shifts for the theoretically predicted structure are within one ppm of these new experimental results, strongly suggesting the tetrameric form has been synthesized. Previous work on five Al4R4 (R = 5H5, C5Me4H, C5Me5, C5Me4iPr, C54Pr) compounds showed a general trend towards an increased likelihood of disassociation into monomeric species in solution as ligand bulk increased. Analysis of Al4Cp8 Ph 4, the sixth and bulkiest compound in this series, indicates a departure from this trend. Bonding characteristics for monomer and tetramer forms in this series are examined in detail via topological analysis to understand this trend. [ABSTRACT FROM AUTHOR]

The new zirconium bent metallocenes (COT)Zr(CptBu2)Cl (1) and (COT)Zr(Cp'')Cl (2) were synthesized in a straightforward manner and in high yields (1: 91%, 2: 86%) by treatment of in situprepared (COT)ZrCl2(THF) with 1 equiv. of K(CptBu2) or K(Cp''), respectively (COT = η;8-cyclooctatetraenyl; CptBu2 = η5-1,3-di-tert- butylcyclopentadienyl; Cp'' = η5-1,3-bis(trimethylsilyl)cyclopentadienyl). Subsequent reaction of 1 with 1 equiv. of phenyllithium afforded the σ-phenyl derivative (CptBu2)Zr(COT)Ph (3) as orange crystals in 83% isolated yield. All three new compounds were structurally characterized through single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

The reaction of Ag[Al(O RF)4] [ RF = C(CF3)3] with Cp*Be-Br was investigated. With the less basic CH2Cl2 as solvent, redox chemistry prevailed, elemental silver and the pentamethylcyclopentenyl cation (Cp*H2+) formed. However, upon changing to the more π-basic solvents fluorobenzene and o-difluorobenzene, the silver metathesis reaction went smooth and produced intermediately the [Cp*Be]+ cation and AgBr. However, the very strong Lewis acid [Cp*Be]+ activated one of the 36 equivalent C-F bonds of the [Al(O RF)4]- anion and finally formed two stable crystalline compounds containing the Cp*Be-F-Al(O RF)3 molecule, which includes a [F-Al(O RF)3]- anion coordinated to the [Cp*Be]+ cation. Cp*Be-F-Al(O RF)3 nevertheless includes some potential to provide [Cp*Be]+ in polar solution. Its potential neutral or ionic fission was investigated by DFT calculations. [ABSTRACT FROM AUTHOR]

The reaction of Ag[Al(O RF)4] [ RF = C(CF3)3] with Cp*Be-Br was investigated. With the less basic CH2Cl2 as solvent, redox chemistry prevailed, elemental silver and the pentamethylcyclopentenyl cation (Cp*H2+) formed. However, upon changing to the more π-basic solvents fluorobenzene and o-difluorobenzene, the silver metathesis reaction went smooth and produced intermediately the [Cp*Be]+ cation and AgBr. However, the very strong Lewis acid [Cp*Be]+ activated one of the 36 equivalent C-F bonds of the [Al(O RF)4]- anion and finally formed two stable crystalline compounds containing the Cp*Be-F-Al(O RF)3 molecule, which includes a [F-Al(O RF)3]- anion coordinated to the [Cp*Be]+ cation. Cp*Be-F-Al(O RF)3 nevertheless includes some potential to provide [Cp*Be]+ in polar solution. Its potential neutral or ionic fission was investigated by DFT calculations. [ABSTRACT FROM AUTHOR]

The dimeric ruthenium complex [Cp∧RuCl2]2 is easily accessible in a one-pot reaction from RuCl3(solv) n and tert-butylacetylene. It features sterically very demanding 'Cp-roof' ligands (Cp∧ = η5-1-methoxy-2,4- tert-butyl-3-neopentylcyclopentadienyl), which impart a unique reactivity. Herein we describe the synthesis and the characterization of novel Cp∧Ru complexes bearing a bridging carbene ligand, a linear imido ligand, or an orthometalated phosphine ligand. Furthermore, the microwave-assisted syntheses of the bimetallic complexes [Cp∧Ru(μ-Cl)3Ru( p-cymene)] and [Cp∧Ru(μ-Cl)3RhCp*] are described. [ABSTRACT FROM AUTHOR]

Abstract. The cyclopentadienyl-substituted iron-bismuth complexes [{Cp(CO)2Fe}BiCl2] ( 1), [{Cp(CO)2Fe}BiBr2] ( 2), [{Cp′′(CO)2Fe}BiBr2] ( 3) and [{Cp*(CO)2Fe}BiBr2] ( 4) were prepared with high yields starting from [Cpx(CO)2Fe]2 [Cpx = C5H5 (Cp), C5H3-1, 3- tBu2 (Cp′′), C5Me5 (Cp*)] and the corresponding bismuth halides. The single crystal X-ray structure analyses of compounds 2- 4 are reported. Comparison of their solubility demonstrates that the steric hindrance in this type of compounds is only slightly higher for compound 3 compared with compound 2 but significantly lower compared with the Cp* derivative 4. Compounds 1- 4 react with nucleophililic reagents such as KO tBu, NaOCH2CH2OCH3, and NaOSiMe3 as well as with water in the presence of an amine to give a mixture of [{Cpx(CO)2Fe}Bi X] ( X = Cl, Br) and [{Cpx(CO)2Fe}3Bi]. In case of a reaction with nBu4NCl and DMAP (dimethylaminopyridine) no such dismutation is observed. Instead the complexes [{Cp(CO)2Fe}BiBr2(DMAP)2] ( 5), [N nBu4]2[{{Cp(CO)2Fe}BiBr3}2] ( 6) and [N nBu4]2[{{Cp(CO)2Fe}BiCl3}2] ( 7) were isolated and characterized by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]