Preparation and Reactions of Base-Free Bis(1,3-di-tert-butylcyclopentadienyl)titanium, Cp′₂Ti, and Related Compounds

Abstract

The titanium(III) metallocene derivatives [1,3-(Me3C)2C5H3]2TiX, Cp′2TiX, X = Cl, Me, H, OH, are prepared and shown to be monomeric with a d1 electron configuration by solid state magnetic susceptibility studies over the temperature range 5–300 K. Reduction of the chloride by potassium amalgam in an argon atmosphere yields the base-free titanocene Cp′2Ti, which is a spin triplet over the temperature range 5–300 K. In contrast, reduction in a nitrogen atmosphere gives the dimetal metallocene Cp′2Ti(N2)TiCp′2, which shows a singlet–triplet equilibrium over the temperature range 5–300 K, which can be modeled by Heisenberg coupling with −2J = 210 cm−1. The base-free titanocene reacts reversibly with H2 or C2H4 to give Cp′2TiH2 and Cp′2Ti(C2H4), respectively. Both adducts are characterized by X-ray crystallography. The base-free titanocene reacts irreversibly with PhCCPh or N2O to give Cp′2Ti(PhCCPh) and Cp′4Ti2(μ-O), which are characterized by X-ray crystallography. In contrast Cp′2Ti(C2H4) reacts with N2O to give the bisoxo-bridged dimetal derivative Cp′4Ti2(μ-O)2.

Thermolysis of titanocene methyl compounds bearing t-butyl- and benzyltetramethylcyclopentadienyl ligands

“…On the other hand, in a recent study on bis(di-t-butylcyclopentadienyl)titanium derivatives the titanocene monomethyl compound [TiMe(g 5 -C 5 H 3 t-Bu 2 ) 2 ] has been found thermally stable upon sublimation at 60-70°C in vacuum [17]. No activation of tbutyl group was also noticed during synthesis of the most sterically crowded attainable t-butyl titanocene derivatives of [Ti(g 5 -C 5 H 3 t-Bu 2 ) (g 5 -C 5 H 2 t-Bu 3 )] [18].…”

Reactivity studies on [Cp′FeI]2: From iron hydrides to P4-activation

“…This is rather surprising considering that the reaction of metal hydrides with dinitrogen is known to be a very attractive route to dinitrogen complexes with different levels of N 2 activation. 64,65 It was therefore of interest to explore the reactivity of 2 and 3 toward P 4 and to compare the results with those of [Cp 0 Fe(CO) 2 ] 2 .…”

Titanium, zirconium and hafnium

“…76 2 Ti(N 2 )TiCp 0 2 ], which exhibits a singlet-triplet equilibrium. 77 Depending upon conditions, reaction of MeOH with the alkyne complex [Cp 2 Ti(Z 2 -Me 3 SiC 2 SiMe 3 )] yields dinuclear [{Cp 2 Ti(OMe)} 2 ] or trinuclear [{Cp 2 Ti(OMe)} 2 {Ti(OMe) 4 }], the latter containing both Ti III and Ti IV . 78 [Cp* 2 Hf] reacts with PhCRCSiMe 3 forming [Cp* 2 Hf(Z 2 -PhC 2 SiMe 3 )], which contains a significantly stronger alkyne-metal interaction than those for Ti and Zr.…”