Zwitterionic d0 Metal Complexes [(Cy2N)3M]+[(μ-Me)B(C6F5)3]− (M = Ti, Zr, Hf) Derived from Tris(dicyclohexylamido)methyl Metal Precursors

Crystal structures of the Lewis acid–base adducts {[(C6H11)2N]3Ti–LB}+[MeB(C6F5)3]−·1.5C7H8; LB = (C6H5)3PO (1), p-F—C6H4CN (2)

In the mol­ecular structures of the two title compounds, the central titanium(IV) atoms are coordinated in a distorted tetra­hedral fashion. Thereby, the titanium atom is stabilized by the Lewis bases tri­phenyl­phosphine oxide (1) and p-fluoro­benzo­nitrile (pFBN) (2) with dative O—Ti and N—Ti bonds, respectively.

The reaction of [(C₆H₁₁)₂N]₃Ti—CH₃ with the Lewis acid B(C₆F₅)₃, followed by addition of the Lewis bases (C₆H₅)₃PO and p-F—C₆H₄CN led to the complex salts tris­(di­cyclo­hexyl­amido)(tri­phenyl­phosphine oxide)titanium methyl­tris(penta­fluoro­phen­yl)borate toluene sesquisolvate, [Ti(C₁₂H₂₂N)₃(C₁₈H₁₅OP)](C₁₉H₃F₁₅B)·1.5C₇H₈, (1), and tris­(di­cyclo­hexyl­amido)(4-fluoro­benzo­nitrile)­titanium methyl­tris­(penta­fluoro­phen­yl)borate toluene sesquisolvate, [Ti(C₁₂H₂₂N)₃(C₇H₄FN)](C₁₉H₃F₁₅B)·1.5C₇H₈, (2), both crystallizing with 1.5 equivalents of toluene solvent mol­ecules. The Lewis acid–base adducts (1) and (2) can be described by dative donor bonds. The packing of the complex cations, anions and solvent mol­ecules in the crystal structure is consolidated by an intricate three-dimensional network of non-classical C—H⋯F inter­actions. Disorder of some of the cyclo­hexyl groups and the toluene solvent mol­ecules is observed.

Techniques in the synthesis of organometallic compounds of Hafnium

Hafnium is a transition metal and it is the 45th most abundant transition element present on the earth. Hafnium has been successfully alloyed with several metals including titanium, iron, and niobium. Hafnium complexes are less active olefin polymerization catalysts. In the current review synthesis of hafnium complexes involving bonding through different linkages like “carbon, nitrogen, oxygen, carbon and oxygen, nitrogen and cobalt nitrogen and oxygen, nitrogen and phosphorus, nitrogen and sulfur, phosphorus and carbon, phosphorus and oxygen, sulfur carbon and oxygen, carbon–nitrogen and oxygen, carbon–nitrogen and phosphorus, carbon–nitrogen oxygen, sulfur and phosphorus, carbon–oxygen phosphorus and nitrogen”. The commonly used solvents for the synthesis of Hafnium complexes are tetrahydrofuran, n-hexane, and toluene, etc. These complexes were mostly reported at different temperatures ranges from −35 to 110 °C with continuous stirring, according to the nature of ligands. An overview of techniques in the synthesis of Hafnium complexes through various routes has been compiled.

FLP behaviour of cationic titanium complexes with tridentate Cp,O,N-ligands: highly efficient syntheses and activation reactions of C–X bonds (X = Cl, F)

Titanium FLPs! Solvent- and catalyst-free Aza-Michael reaction provides β-amino ketones which were employed as ligand precursors for the convenient synthesis of novel cationic titanium complexes with tridentate Cp,O,N-ligand frameworks, which activate C–X bonds in a FLP-like manner.

Crystal structure of a zwitterionic azaallyl zirconiumamide complex bearing a Zr+-μ-CH3—B− moiety and one equivalent of n-hexane as a solvent

The zirconiumamide complex [(cyclohex-1-enyl)cyclohexylamido]bis(dicyclohexylamido)[methyltris(pentafluorophenyl)borato]zirconium(IV) hexane monosolvate, [Zr{N(C6H11)2}2{N(C6H11)(C6H9)}{BCH3(C6F5)3}]·C6H14, is zwitterionic and bears a Zr+—μ-CH3—B− moiety. The reaction of tris(dicyclohexylamido)methylzirconium with the strong Lewis acid tris(pentafluorophenyl)borane results in the formation of an azaallyl zirconium motif by the loss of H2 in one dicyclohexylamido ligand, as shown by single-crystal X-ray diffraction. The ZrIV cation is coordinated to the N atoms of two dicyclohexylamido ligands, the π-system of one azaallyl ligand, and to the μ-CH3—B unit, resulting in a distorted tetrahedral coordination environment. The Zr—N distance to the azaallyl ligand is elongated, whereas the Zr—C distance to this moiety is found to be shortened in comparison with those to the two Cy2N groups (Cy is C6H11).

Crystal structure of n-butyl-tris(dicyclo-hexylamido)hafnium(IV), C40H75HfN3

C40H75HfN3, monoclinic, P21/n (no. 14), a = 10.7446(3) Å, b = 13.6547(4) Å, c = 26.5464(9) Å, β = 92.2375(15)°, V = 3891.8(2) Å3, Z = 4, Rgt(F) = 0.0195, wRref(F2) = 0.0461, T = 100(2) K.

Theoretical insights into C–C bond formation through isonitrile insertion into a Cp*Ti complex

Reaction of Cp*(Cl)Ti(2,3-dimethylbutadiene) with isonitriles is studied using DFT, detailed elementary reaction steps and N-substitution effects of isonitrile are examined.

Theoretical insights into the reaction of Cp*(Cl)Hf(diene) with isonitriles

The reaction of Cp*(Cl)Hf(2,3-dimethylbutadiene) with isonitriles is theoretically investigated, and detailed elementary reactions and the substitution effects are examined.