Different Inertness of Titanocene [Cp₂Ti] and Decamethyltitanocene [Cp*₂Ti] in Reactions with N,N‐Bis(trimethylsilyl)sulfurdiimide – Elimination of Tetramethyl­fulvene and Formation of Half‐Titanocene Complexes

Abstract

The reaction of the titanocene alkyne complex [Cp*2Ti(η2‐Me3SiC2SiMe3)] (1) (Cp* = η5‐pentamethylcyclopentadienyl) with N,N‐bis(trimethylsilyl)sulfurdiimide (2) results in the formation of 1,2,3,4‐tetramethylfulvene (3) as well as three titanium complexes 4, 5 and 6. During the reaction, formal elimination of one Cp* ligand induces a series of C–H and N–S bond activation steps, thus yielding the products. The molecular structures of complex 5 and of the free fulvene were determined by X‐ray crystallographic analysis. Evidently, in these reactions [Cp*2Ti] is less stable than [Cp2Ti]; a possible reason was found to be the well‐known intramolecular C–H activation yielding the tautomeric tetramethylfulvene hydride species, from which 1,2,3,4‐tetramethylfulvene (3) can dissociate.

Synthesis and X-ray Crystal Structure of Diimidosulfinate Transition Metal Complexes

“…Because of the high vapor pressure of ZnMe 2 and its high reactivity toward water and oxygen, all manipulations must be performed under inert gas conditions. NMR spectra were recorded on a Bruker Avance 300 spectrometer at 25 °C at 300.1 MHz ( 1 H) and 75.5 MHz ( 13 C) and referenced to internal C 6 D 5 H ( 1 H, δ = 7.154; 13 C, δ = 128.0) and internal THF-d 8 ( 1 H, δ = 3.580, 1.730; 13 C, δ = 25.2, 67.4). IR spectra were recorded on a Bruker ALPHA-T FT-IR spectrometer equipped with a single reflection ATR sampling module.…”

“…[MeZnN(SiMe 3 )S(Me)NSiMe 3 ] 2 1. S(NSiMe 3 ) 2 (0.50 g, 2.42 mmol) was dissolved in 3 mL of toluene and 2.02 mL of ZnMe 2 (2.42 13 C NMR (75 MHz, C 6 D 6 , 25 °C): δ = −5.27 (ZnMe), 1.99 (SiMe 3 ), 48.09 (SMe). ATR-IR: ν = 2949, 2901, 2830, 1414, 1294, 1245, 1161, 1051 .…”

“…1 H NMR (300 MHz, C 6 D 6 , 25 °C): δ = 0.21 (s, 9 H, SiMe 3 ), 0.42 (s, 9 H, SiMe 3 ), 0.44 (s, 9 H, SiMe 3 ), 0.57 (s, 9 H, SiMe 3 ). 13 C NMR (75 MHz, C 6 D 6 , 25 °C): δ = 0. 89 (SiMe 3 ), 2.10 (SiMe 3 ), 2.34 (SiMe 3 ), 3.01 (SiMe 3 2949,2896,1442,1402,1244,987,900,875,825,769,713,676,663,617,486,427, 409 cm −1 .…”

“…2.4677 Å), which clearly exceed the sum of the covalent radii (1.98 Å 21 ) but which are below the sum of the van-der-Waals radii (2.94 Å 22 ). The S−N bond lengths range from 1.6134 (13) to 1.6389(11) Å (av. 1.6255 Å), which agrees very well with values previously reported for S-alkyl diimidosulfinate complexes, 25 clearly proving the presence of delocalized π-electrons within the N−S−N unit.…”

“…7,10 Moreover, simple Lewis acid−base adducts of sulfurdiimide with several metal halides such as TiCl 4 , GaCl 3 , and SnCl 4 , respectively, have been synthesized, 11 while Weidlein et al reported on insertion reactions of bis-(trimethylsilyl)sulfurdiimide with trimethylalane, -gallane, and -indane MMe 3 (M = Al, Ga, In). 11c In contrast, reactions of S(NSiMe 3 ) 2 with either a zirconium imide or the titanocene alkyne complex [Cp 2 Ti(η 2 -Me 3 SiC 2 SiMe 3 )] yielded titanium trisimidosulfite complexes in a rather complex reaction mechanism, 12,13 while the analogous reaction with [Cp 2 Ti(η 2 -Me 3 SiC 2 SiMe 3 )] gave an unusual four-membered metallacycle. Surprisingly, reactions of sulfurdiimides with homoleptic group 12 (Zn) metal complexes MR 2 as well as heteroleptic group 4 metal complexes Cp*MMe 3 (M = Ti, Zr, Hf), in which the organic groups also exhibit a high carbanionic character, have not been reported to the best of our knowledge.…”