Structural Investigation in Solution of a Series of Five-Coordinate Bisphosphanylaryl Ruthenium(II) Complexes

Dani, Paulo; Klink, Gerard P. M. van; Koten, Gerard van

doi:10.1002/1099-0682(200007)2000:7<1465::aid-ejic1465>3.0.co;2-p

Cited by 14 publications

(28 citation statements)

References 23 publications

(18 reference statements)

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“…The spectroscopic properties of both 5 and 6 are similar to those reported for 1a and 2 , implying that the two compounds have similar structures, i.e., square pyramidal structures with the PPh 3 ligand occupying the apical position. , The 1 H NMR spectrum of both 5 and 6 , recorded in CD 2 Cl 2 at room temperature, displayed two sets of virtual doublets of triplets ( 2 J HH = 16 Hz and 2 J PH = 6 Hz) for the methylene protons of the PCP-pincer ligand. This indicates that the two PR 2 groups are trans to each other and that the PCP-ligand is coordinated to the ruthenium(II) center in a meridional fashion. , In the 1 H NMR spectrum of 5 and the 19 F NMR spectrum of 6 two resonance patterns are found for the MeOC 6 H 4 and CF 3 C 6 H 4 groups, respectively, indicating that in both complexes the ( p -MeOC 6 H 4 ) and ( p -CF 3 C 6 H 4 ) groups are diastereotopic.…”

Section: Resultssupporting

confidence: 63%

“…The corresponding ruthenium(II) complexes 5 , 6 , and 8a 9 have been prepared via the transcyclometalation (TCM) reaction, an efficient method for the preparation of achiral and chiral 2b, [RuCl(PCP)(PPh 3 )] complexes. Thus, reaction of the complex [RuCl{C 6 H 3 (CH 2 NMe 2 ) 2 -2,6}(PPh 3 )] ([RuCl(NCN)(PPh 3 )], Scheme ) with the PCP-pincer ligands 3 , 4 , and 7 , respectively, in 1:1 molar ratio at 80 °C, afforded the air-sensitive 5 and 6 , respectively, as deep green-colored solids and the remarkably air/moisture-stable 8a as a red-colored powder.…”

Section: Resultsmentioning

confidence: 99%

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Electronic Effects in PCP-Pincer Ru(II)-Based Hydrogen Transfer Catalysis

et al. 2007

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The synthesis and characterization of novel cyclometalated ruthenium(II) complexes [RuCl(PCP OMe )-(PPh 3 )] and [RuCl(PCP CF3 )(PPh 3 )] containing monoanionic, tridentate coordinating PCP-pincer ligands [C 6 H 3 {CH 2 P(p-MeOC 6 H 4 ) 2 } 2 -2,6] -(PCP OMe ) and [C 6 H 3 {CH 2 P(p-CF 3 C 6 H 4 ) 2 } 2 -2,6] -(PCP CF3 ) are reported. These compounds have been tested as catalyst precursors in the hydrogen transfer reaction of cyclohexanone to cyclohexanol in 2-propanol using NaOH as a base. The initial rate of the hydrogen transfer reaction appeared to depend on the electronic character of the Ar 2 P-groups of the PCP-pincer ligand. Among the catalyst precursors studied, the complex [RuCl(PCP CF3 )(PPh 3 )] was found to exhibit the highest activity and the initial TOF exceeded that observed for the Ph 2 P analogue [RuCl(PCP Ph )-(PPh 3 )]. Most importantly, catalysis performed with [RuCl(PCP CF3 )(PPh 3 )] does not require pretreatment of the precursor in the absence of substrate. Conversely, a different catalytic profile and a low activity were observed when either the electron-poor [RuCl{C 6 H 3 (CH 2 P(C 6 F 5 ) 2 ) 2 -2,6}(PPh 3 )] ([RuCl(PCP F20 )-(PPh 3 )]) complex or its triflate analogue was used as catalyst precursors. NMR studies and ESI-MS measurements provided information concerning the catalytically active species formed during the pretreatment of the precursor complexes. The results indicate that during the pretreatment period a monoanionic, monohydride ruthenium(II) species, Na[Ru(H)(PCP iPr )(OiPr)(PPh 3 )], is selectively formed. The latter hydride complex was also obtained via an independent synthetic route. On the basis of both the present results and those previously reported in literature, a mechanism is proposed.

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Section: Resultssupporting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Electronic Effects in PCP-Pincer Ru(II)-Based Hydrogen Transfer Catalysis

et al. 2007

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“…Worthy of note is the capability of RuCl 2 (PPh 3 ) 3 to cyclometallate so‐called “O'Donnell Schiff bases” such as diphenylmethylene glycine ester, the latter behaving as a tridentate ligand in 14 (Scheme ),30 and to efficiently cyclometallate PCP ligands as reported by van Koten et al15 and Fogg et al31…”

Section: Cycloruthenationmentioning

confidence: 95%

“…Tridentate ligands of the pincer PCP type have also displayed some reactivity towards RuCl 3 · 3H 2 O 15. A typical reaction carried out in boiling methanol would only yield low amounts of a dinuclear bridged species 5 (Scheme ).…”

Section: Cycloruthenationmentioning

confidence: 99%

Cycloruthenated Compounds – Synthesis and Applications

et al. 2009

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The syntheses of cycloruthenated compounds by several methods, and especially by the C-H activation pathway, have been reviewed. Many ruthenium-containing starting materials lead to these interesting organometallic compounds, which have found various applications in different fields of chemistry. Their reactivity highlights both the variety of reactions that were found to occur at the Ru-C bonds as well as the inertness of the organometallic moiety when these species are exposed to strongly oxidizing molecules or to reactive halogenation reagents. Their use as catalyst precursors showed them to be particularly efficient for hydrogenation reactions, either by H 2 or by hydride transfer.

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“…Thus, the presence of a bis(ortho)-metalated BrϪPCP ligand is clearly apparent from the 13 C NMR spectrum, where RuϪC ipso of 9 appears at δ ϭ 173.85 as a characteristic doublet ( 2 J CP ϭ 16 Hz). [14] The diastereotopic benzylic protons of the cyclometalated ligand give rise to signals at δ ϭ 2.67 and 3.63 in the 1 H NMR spectrum, each with integrals corresponding to four protons. On the other hand, all of the benzylic protons of the bridging BrϪPCHP ligand appear as a single doublet at δ ϭ 3.10 ( 2 J HP ϭ 9 Hz).…”

Section: Ruthenium Complexes Containing One Neutral R؊pchp Ligandmentioning

confidence: 99%