A Novel Cyclopentadienone and its Ruthenium and Iron Tricarbonyl Complexes

Abstract

Dedicated to Prof. Wolfgang Beck on the occasion of his 90th birthday.A simple and efficient protocol allows the oxidation of the cyclopentadiene derivative 5H-dibenzo[e,h]-dibenzo [3,4 : 6,7] cyclohept [1,2-a]azulene (Cp C H) provide according ketone Cp C O. Comparable to the situation found for Cp C H, the bending of the four annulated six-membered rings defines the C 2 symmetric molecular structure of Cp C O. The cyclopentadienone Cp C O readily reacts with [Ru 3 (CO) 12 ] and [Fe 3 (CO) 12 ] to generate tricarbonyl complexes of the type [(η 4 -Cp C O)M(CO) 3 ]. In contrast to [(η 4 -Cp C O)Ru(CO) 3 ], the tricarbonyliron(0) complex is sensitive to oxygen and moisture. Refluxing [(η 4 -Cp C O)Ru(CO) 3 ] in isopropanol makes the hydrido-bridged complex [((η 4 -Cp C O) 2 H) Ru 2 (CO) 4 H] accessible, an analogue to Shvo's catalyst. Both ruthenium complexes and their ligand Cp C O were characterized spectroscopically and by single crystal x-ray diffraction. The activity of [(η 4 -Cp C O)Ru(CO) 3 ] was investigated for a series of transfer hydrogenation reactions.

Phosphine Functionalized CpC Ligands and Their Metal Complexes

“…whose structures and reactivities correspond to those of the Shvo and Knölker catalysts respectively [20]. Here, we now report on novel phosphine-functionalized derivatives o 1 and their use as ligands in transition metal chemistry.…”

“…By reacting the anion (Cp C ) −1 (1 −1 ) with oxygen, the corresponding ketone is accessible in good yield. With this η 4 -coordinating dienone, we were able to synthesize ruthenium and iron compounds whose structures and reactivities correspond to those of the Shvo and Knölker catalysts, respectively [20]. Here, we now report on novel phosphine-functionalized derivatives of 1 and their use as ligands in transition metal chemistry.…”

4,5-Di-tert-butyl-1,3,6,8-tetraphenyl-4,5,8a,8b-tetrahydro-as-indacene

“…Extraction of the light brown solid with toluene (20 mL) under N 2 , followed by filtration of insoluble salts over celite, evaporation of the toluene, and vacuum drying, gave the crude product 2 as an off-white-colored solid (1.07 g, 73%), which was >95% pure ( 1 H NMR). 1 S12, Supporting Information). CAUTION!…”

“…The direct reaction of triplet O 2 with cyclopentadienyl rings has not been a frequently used tool in synthesis, aside from the construction of the important cyclopentadienone ligand from highly substituted cyclopentadienyl precursors [1]. Scattered reports from the literature describe the interaction of triplet O 2 with cyclopentadienyl-M and mixed (cyclopentadienyl)(arene)-M compounds to give substituted π-(cyclopentadiene)M(η-cyclopentadienyl) complexes [2], as well as both stable and unstable metal cyclopentadienyl [3] and metal arene peroxidic dimers [4][5][6].…”