Reactions of cyclopentadiene with carbonyl-ruthenium and -osmium complexes

Abstract

Both Ru,(CO),, and [H,Ru,(CO),,] react rapidly with cyclopentadiene in the absence of oxygen to yield [RuH(CO),(q-C,H,)],(11; M = Ru), quantitatively, characterised in part via high-yield conversion into [RuH(CO)(PPh,) (q-C5H5)]. In the presence of oxygen [{Ru(CO),(q-C5H5)},], (111; M = Ru), is obtained in ca. 70% yield. The complex [Ru(CO),(q-C,H,)],( I ; M = Ru), has been isolated and shown to be a direct precursor of (11). Treatment of ( I ; M = Ru) with [Ph,C] [BF,] gives [Ru(CO),(q-C5H5)] [BF,], while triphenylphosphine displaces C5H6 forming [Ru(CO),(PPh,),]. Carbonylation (1 00 atm) of [RuH(CO) (PPh,) (q-C5H5)] in the presence of Et,O.BF, gives [Ru(CO),(PPh,) (-q-C5H5)] [BF,] in high yield. A minor product of the reaction of Ru,(CO),, and C5H6 is tentatively identified as [ R U , H ( C O ) ~( ~~-C ~H ~) ] , (IV) ; a related fluxional osmium complex, [Os,H,(CO),(q2-C5H4)],is obtained on treating [H20s3(CO),,] with C5H6. Low-yield formation of ( I ; M = 0 s ) and (11; M = 0 s ) from reaction of Os,(CO),,, [H,Os,(CO),,],or [H,Os(CO),] with C5H6 is described.IT has been suggested 1,2 that the reaction of iron pentacarbonyl with cyclopentadiene proceeds to the observed product [{Fe(CO),(q-C,H,)},], (111; M = Fe),, via intermediate ?-C,H, and q-C,H, iron complexes, as shown in the Scheme. This is now generally accepted, following the subsequent isolation of [Fe(CO),(q-C,H,)], ( I ; M =

Terthienyl-Based Redox-Switchable Hemilabile Ligands: Transition Metal Polymeric Complexes with Electrochemically Tunable or Switchable Coordination Environments?

“…Compounds 3 a,b were prepared by stirring 2 a,b in CH 2 Cl 2 with AgBF 4 at room temperature. The B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 and B(C 6 F 5 ) 4 salts (4 a,b) were prepared from 3 a,b by metathesis with appropriate alkali metal salts (Scheme 1). Each salt has advantages with respect to crystallization, solubility, or spectroelectrochemistry, and thus the use of a particular salt reflects the best balance of these properties.…”

“…Complexes 2 a,b were synthesized from the new ligands 1 a,b by a modification of literature procedures [4] for synthesizing analogous, isoelectronic complexes (see Supporting Information) (Scheme 1). Compounds 3 a,b were prepared by stirring 2 a,b in CH 2 Cl 2 with AgBF 4 at room temperature.…”

“…Poly-4 b has been electrochemically deposited onto an Au electrode by electrochemically oxidizing 4 b in CH 2 Cl 2 /0.1m LiB(C 6 F 5 ) 4 . The characteristic oxidative polymerization wave for this terthienyl compound is observed at 765 mV vs. FcH/ FcH , and the reversible oxidation/reduction wave for a typical deposited polymer is E 1/2 540 mV vs. FcH/FcH .…”

“…The resulting dark brown suspension was stirred for 48 h at À 78 8C during which time it turned dark green. The NMR spectrum recorded for the dark green solution obtained after the reaction mixture had been allowed to warm to room temperature and the solvent pentane had been exchanged for C 6 D 6 revealed in addition to small amounts of tBu 3 SiH (hydrolysis product of tBu 3 SiNa; identification by comparison with an authentic sample [5] ), R* 2 InÀInR* 2 (identification by comparison with an authentic sample [4] ) and 3 in a molar ratio of about 1:1. After removal of insoluble products (Cp*Na) from the original solution in pentane by filtration, removal of all volatile components under an oil pump vacuum (tBu 3 SiH, pentane), and dissolution of the dark green residue in benzene (10 mL), 3 (0.072 g, 0.034 mmol, 32 %) crystallized as dark green parallelpipeds in the course of 7 d at room temperature.…”

neuer substituierter ƞ5 -Cyclopentadienyl-ruthenium-carbonyl-Kationen / Syntheses and Spectral Data of New Substituted ƞ5 -Cyclopentadienyl Ruthenium Carbonyl Cations

“…Verbindungen mit der CONH2-Gruppe bilden sich ohne Freisetzung von CO durch Umsetzung kationischer CO-Komplexe oder von Halogenometallcarbonylen [3] im Gegensatz zum Eisen nur wenige Beispiele bekannt sind [8]. Daher sollen im folgenden Synthesen bisher unbekannter, substituierter, kationischer ?/ 5 -Cyclopentadienyl-ruthenium-carbonyl-Komplexe aus r; 5 -C5H5Ru(CO)2Cl beschrieben werden, die für die Darstellung neuer Carbamoyl-carbonyl-Verbindungen des Rutheniums in flüssigem Ammoniak geeignet sind und über die in Kürze an anderer Stelle berichtet wird.…”