Synthesis and characterization of conjugated organometallic dimers and oligomers of ruthenium(II) complexes

Abstract

The carbonyl hydrido complex RuHCl(CO)(PPh3)3 reacts with diynes HC2RC2H (R = p-C6H4, p-C6H4-C6H4) by insertion to give the five-coordinate vinyl ruthenium dimeric compounds [RuCl(CO) (PPh3)2]μ-CH=CH-R-CH=CH) in nearly quantitative yields. Additions of 3,5-dimethylphenylisocyanide (CNC8H9) or 4-phenyl pyridine ligand to the alkenyl complexes produce the six-coordinate complexes (C8H9NC)Ru(CO)Cl (PPh3)2 μ-CH=CH-R-CH=CH)Ru(CO)Cl(PPh3)2 (CNC8H9), (C6H5-C6H4N)Ru(CO)Cl(PPh3) 2μ-CH=CH-R-CH=CH)Ru(CO)Cl(PPh3)2 (NC5H4-C6H5). This reaction was applied to the synthesis of conjugated organometallic metal vinyl linkage containing oligomers [Ru(CO)Cl(PPh3)2(μ-CH=CH-R-CH=CH)Ru(CO) Cl(PPh3)2(μ-L)]n (L = 2,3,5,6-tetramethylphenyldiisocyanide, 4,4-bipyridine). Reactions between [Ru(THF)(PPh3)2(Cp)]+ and diynes gave further examples of dinuclear vinylidene ruthenium complexes [Ru]=C=CH-R-CH=C=[Ru] {[Ru] = Ru(PPh3)2(Cp)+, R = p-C6H4, p-C6H4- C6H4}. Subsequent deprotonation of vinylidene complexes by NaOMe produced corresponding acetylide dinuclear complexes. A new synthetic route to compounds with "naked" C5 bridging two metal centers is reported. Reaction of 2 equivalents of [Ru(PPh3)2(Cp)Cl] with HC2CH(OH)C2H, NaPF6 and AgBF4 leads to dinuclear cationic C5-H complex [Cp(PPh3)2Ru=C=C-CH=C=C=Ru(PPh3)2 Cp][PF6 after treatment with alumina. The cationic C5-H complex could be converted into the corresponding neutral C5 complex Cp(PPh3)2Ru≡C-C≡C-C[identical to][identical to] C-Ru(PPh3)2Cp by treatment with KOt8u. The monohydrido complex RuHCl(CO)(PPh3)3 reacts with HC≡CC(OH)RlR2 to give the hydroxyvinyl compounds RuCl((E)-CH≡CHC(OH)RlR2} (CO)(PPh3)2 (R1 = R2 = H; R1= R2 = Me; R1=Ph, R2 = Me; R1 = Me, R2 = Et), which by reaction with HBF4 afford [RuCl(=CHCH=CRlR2)(CO)(PPh3)2] [BF4] (R1 = R2 =Me; R1 = Ph, R2 = Me). Treatment of hydroxyvinyl. compounds in CH2 Cl2 with alumina affords corresponding dehydrated compounds RuCl(-CH=CH-CR'= CH2)(CO)(PPh3)2 (R' = Ph, Me). The hydroxyvinyl and butadienyl complexes react with 4-phenylpyridine to give corresponding six-coordinate complexes.

Date of Award	1995
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology