A Facile Route to 1-Trifluoromethyl-2,3,4,5-tetramethylcyclopentadienyl Ruthenium Half- and Mixed-Sandwich Compounds

Abstract

A series of half-and mixed-sandwich (Cp q ) 1-trifluoromethyl-2,3,4,5-tetramethylcyclopentadienide) ruthenium compounds have been synthesized from a new Cp q Ru synthon, [Cp q Ru(NCCH 3 ) 3 ](PF 6 ). [Cp q Ru-(NCCH 3 ) 3 ](PF 6 ) is efficiently generated by photolysis of [Cp q RuBz](PF 6 ) in acetonitrile with a quantum yield of approximately 0.34. The methods described here should be useful for the synthesis of other compounds that contain the Cp q Ru group.

One‐Step Preparation of [RuCp*(η6‐arene)]+ Sandwich Complexes

“…We discovered the monomethoxy sandwich 14 to be a side product (12%) when reacting ethylbenzene via the oligomer route (Scheme 3; [25] Experimental Section General: All reactions were carried out under an argon atmosphere with distilled, non-anhydrous solvents. Yields refer to purified compounds.…”

Site Selectivity of [RuCp*]+ Complexation in Cyclopenta[def]triphenylenes

“…2,6-Di(tert-butyl)-9,10-dihydroxy-4H-cyclopenta[def ]-triphenylene (8). BBr 3 (0.58 mL, 6.06 mmol) was added dropwise to a solution of 2 (0.500 g, 1.21 mmol) in dry DCM (25 mL) at 0°C.…”

“…3 The resulting ruthenium sandwich complexes have been studied for their interesting electrochemical and spectroscopic properties, as well as their catalytic activity. 8,9 The most popular synthetic route toward simple [RuCp*(η 6 -arene)] + complexes involves the formation of a [RuCp*-(CH 3 CN) 3 ] + complex, which is reacted with the appropriate arene ligand with heating or UV irradiation. 2,5,10 These methods are generally useful and robust; however, the need for toxic or expensive Sn and Ag reagents leaves room for improvement.…”

Ruthenium Complexes Bearing Bulky Pentasubstituted Cyclopentadienyl Ligands and Evaluation of [Ru(η5‐C5Me4R)(MeCN)3][PF6] Precatalysts in Nucleophilic Allylic Substitution Reactions

“…As a result of the lability of their acetonitrile ligands, the cyclopentadienyltris(acetonitrile)ruthenium cations continue to provide a popular entry to a rich coordination chemistry. To hinder the undesired formation of ruthenocene, their access was based on the removal, under UV‐irradiation conditions in acetonitrile, of the benzene ligand from [Ru(η 5 ‐cyclopentadienyl)(η 6 ‐benzene)] + intermediates 1–3. Such a procedure has also been successful for cyclopentadienyl ligands bearing a coordinating phosphane or pyridine side arm 4.…”

“…Such a procedure has also been successful for cyclopentadienyl ligands bearing a coordinating phosphane or pyridine side arm 4. Depending on the nature of the cyclopentadiene, the synthesis of the intermediates requires the treatment of [(η 6 ‐benzene)RuCl 2 ] 2 with cyclopentadienylthallium derivatives,1,2,4 although a “one‐pot” procedure starting from RuCl 3 · 3H 2 O, cyclopentadiene, benzene and zinc as a reducing reagent was efficient in the cases of trifluoromethyltetramethylcyclopentadiene and pentamethylcyclopentadiene 3,5. For the simple [Ru(η 5 ‐C 5 H 5 )(MeCN) 3 ] + cation, efforts have been made to prepare the corresponding [Ru(η 5 ‐cyclopentadienyl)(η 6 ‐benzene)] + intermediate without the involvement of toxic thallium 6.…”