Titanocene pentasulfide

Titanocene pentasulfide

Names
Other names titanocene pentasulfide
Identifiers
CAS Number	12116-82-4 Y
Properties
Chemical formula	C10H10S5Ti
Molar mass	338.382
Appearance	red solid
Structure
Coordination geometry	Dist. tetrahedral
Vapor pressure	{{{value}}}
Related compounds
Related compounds	Zirconocene pentasulfide Titanocene dichloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Titanocene pentasulfide is the organotitanium compound with the formula (C₅H₅)₂TiS₅, commonly abbreviated as Cp₂TiS₅. This metallocene exists as a bright red solid that is soluble in organic solvents. It is of academic interest as a precursor to unusual allotropes of elemental sulfur as well as some related inorganic rings.

Preparation

Titanocene pentasulfide is prepared by treating Cp₂TiCl₂ with polysulfide salts: It was first produced by the addition of elemental sulfur to titanocene dicarbonyl:

(C₅H₅)₂Ti(CO)₂ + ​⁵⁄₈ S₈ → (C₅H₅)₂TiS₅ + 2 CO

The complex is viewed as a pseudotetrahedral complex of Ti(IV). The Ti–S distances are 2.420 and 2.446 Å and the S–S bond distances are of a normal range, 2.051–2.059 Å. The molecule exhibits a dynamic NMR spectrum owing to the chair–chair equilibrium of the TiS₅ ring which equivalizes the Cp signals at high temperatures.

Reactions

Cp₂TiS₅ reacts with sulfur and selenium chlorides, E_xCl₂, to afford titanocene dichloride and various S_5+x and S₅Se_x rings. Illustrative is the synthesis of S₇ from disulfur dichloride:

(C₅H₅)₂TiS₅ + S₂Cl₂ → (C₅H₅)₂TiCl₂ + S₇

It also reacts with alkenes and ketenes to give heterocycles composed of Ti, C and S. With trialkylphosphines, the cycle dimerize into rings of various sizes, depending on the trialkylphosphine used.

File:Selected reactions of titanocene pentasulfide.png

Selected reactions of titanocene pentasulfide