Ein quadratisch‐planarer Ruthenium(II)‐Komplex mit Low‐Spin‐ Konfiguration

Askevold, Bjorn; Khusniyarov, Marat M.; Herdtweck, Eberhardt; Meyer, Karsten; Schneider, Sven

doi:10.1002/ange.201002296

Cited by 13 publications

(22 citation statements)

References 31 publications

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“…Preliminary results reported for 2 (DFT, B3LYP/6-31 + G**) indicated a small singlet/triplet excitation energy. [14] Revaluation within the present comprehensive study using density functional theory with several functionals and referencing of these results using coupled cluster calculations on simpler, PR 2 -truncated models (R = Me, H; the Supporting Information) corroborate this view. Note that the variation of the functional shows the typical behavior, that is, a slight preference for the higher spin-state for hybrid func- ).…”

Section: Electronic Structure Calculationssupporting

confidence: 81%

“…[16] The highfield shift of one CH 3 1 H NMR signal at d = À0.61 ppm suggests CÀH agostic interactions with the metal center at the vacant coordination site, which is confirmed by single-crystal X-ray diffraction (see below). This observation contrasts with [RuHCl{L 2 tBu}], [14] which is attributed to the weaker chloride versus hydride trans influence in 4.…”

Section: Syntheses and Spectroscopic Characterizationmentioning

confidence: 68%

“…Dehydrogenation of the ligand backbone is confirmed by Scheme 1. Structure of Caulton's disilylamido pincer complex 1 and syntheses of hydrocarbylamido complexes in this study: a) DT, ÀH 2 , THF, several weeks; b) À20 8C, KOtBu, THF; [14] c) 5 8C, [KN(SiMe 3 ) 2 ], benzene; d) À78 8C to RT, benzoquinone (1 equiv), THF; e) À78 8C to RT, benzoquinone (2 equiv), THF; f) À78 8C to RT, CO, THF. [16] The highfield shift of one CH 3 1 H NMR signal at d = À0.61 ppm suggests CÀH agostic interactions with the metal center at the vacant coordination site, which is confirmed by single-crystal X-ray diffraction (see below).…”

Section: Syntheses and Spectroscopic Characterizationmentioning

confidence: 99%

“…[13] We recently presented a related, square-planar ruthenium(II) dialkylamido complex, [RuCl{L 1 tBu}] (2, Scheme 1) and its use in small-molecule activation. [14,15] The temperature-dependent solution NMR data was rationalized with an LS ground state and an energetically low-lying IS excited state. Stabilization of the LS configuration was attributed to the presence of one single-faced, strong p-donor (Figure 1, right).…”

Section: Introductionmentioning

confidence: 99%

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Square‐Planar Ruthenium(II) Complexes: Control of Spin State by Pincer Ligand Functionalization

Askevold

Khusniyarov

Kroener

et al. 2014

Chemistry A European J

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Functionalization of the PNP pincer ligand backbone allows for a comparison of the dialkyl amido, vinyl alkyl amido, and divinyl amido ruthenium(II) pincer complex series [RuCl{N(CH2 CH2 PtBu2 )2 }], [RuCl{N(CHCHPtBu2 )(CH2 CH2 PtBu2 )}], and [RuCl{N(CHCHPtBu2 )2 }], in which the ruthenium(II) ions are in the extremely rare square-planar coordination geometry. Whereas the dialkylamido complex adopts an electronic singlet (S=0) ground state and energetically low-lying triplet (S=1) state, the vinyl alkyl amido and the divinyl amido complexes exhibit unusual triplet (S=1) ground states as confirmed by experimental and computational examination. However, essentially non-magnetic ground states arise for the two intermediate-spin complexes owing to unusually large zero-field splitting (D>+200 cm(-1) ). The change in ground state electronic configuration is attributed to tailored pincer ligand-to-metal π-donation within the PNP ligand series.

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Section: Electronic Structure Calculationssupporting

confidence: 81%

Section: Syntheses and Spectroscopic Characterizationmentioning

confidence: 68%

Section: Syntheses and Spectroscopic Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Square‐Planar Ruthenium(II) Complexes: Control of Spin State by Pincer Ligand Functionalization

Askevold

Khusniyarov

Kroener

et al. 2014

Chemistry A European J

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“…DFT analysis of the d 8 ‐M{MeB(CH 2 PMe 2 ) 3 } (M=Rh, Ir) fragments indicates a small difference in energy in favor of the triplet versus the singlet state (3.0 and 2.0 kcal mol −1 for Rh and Ir, respectively). However, this difference may be meaningless because of the tendency of the B3LYP functional to stabilize high‐spin species . The consequences of the spin pairing are: a distortion of the framework that results in distinct M−P bond lengths and P‐M‐P bond angles that reduces the symmetry from C 3 (triplet) to C s (singlet), and a drastic energy difference (2.36 and 2.13 eV for Rh and Ir, respectively) between the HOMO (2e a ) and LUMO (2e s ) that stabilizes the singlet state and leaves empty the orbital 2e s of parentage d yz .…”

Section: Resultsmentioning

confidence: 99%

Pseudo‐tetrahedral Rhodium and Iridium Complexes: Catalytic Synthesis of E‐Enynes

Geer

Julián

López

et al. 2018

Chemistry A European J

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The reactions of the rhodium(I) and iridium(I) complexes [M(PhBP )(C H )(NCMe)] (PhBP =PhB(CH PPh ) ) with alkynes have resulted in the synthesis of a new family of pseudo-tetrahedral complexes, [M(PhBP )(RC≡CR')] (M=Rh, Ir), which contain the alkyne as a four-electron donor. The reactions of these unusual compounds with two-electron donors (L=PMe , CNtBu) produced a change in the "donicity" of the alkyne from a 4e to a 2e donor to give five-coordinate complexes. These were the final products with the iridium complexes, whereas further reactions took place with the rhodium complexes. In particular, C(sp)-H bond activation of the alkyne occurred leading to hydrido alkynyl complexes. This process is essential for the further reactivity of the alkynes, and if the alkyne itself was used as reagent, E-enyne complexes were obtained. As a consequence of this chemistry, we show that the complex [Rh(PhBP )(C H )(NCMe)] is a very efficient pre-catalyst for the regioselective di- and trimerization of terminal alkynes to E-enynes and benzene derivatives, respectively. Interestingly, acetonitrile significantly enhanced the catalytic activity by facilitating the C(sp)-H bond activation step. A hydrometalation mechanism to account for these experimental observations is proposed.

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Quadratisch‐planare Iridium(II)‐ und Iridium(III)‐Amidokomplexe mit einem PNP‐Pinzettenliganden

et al. 2011

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Koordinationsverbindungen der Edelmetalle nehmen eine zentrale Stellung in der homogenen Katalyse ein. Die Präfe-renz zur geschlossenschaligen elektronischen Struktur prä-destiniert solche Komplexe zu formalen Zwei-ElektronenRedoxreaktionen (oxidative Addition/reduktive Eliminierung).[1] Die Bedeutung von Ein-Elektronen-Reaktionen der Platinmetalle, z. B. bei radikalischen H 2 -, C-H-und C-C-Aktivierungen oder bei katalytischen Oxidationen, wurde bereits demonstriert, [2][3][4][5] dennoch sind voll charakterisierte Metalloradikale noch immer selten.[ [8]Ebenso sind Platinmetallkomplexe mit gerader Valenzelektronenzahl und elektronischer High-Spin-Konfiguration wegen der generell hçheren Ligandenfeldaufspaltung der 4d/ 5d-Metallionen als bei 3d-Metallen sehr selten. Eine Ausnahme bilden quadratisch-planare d 6 -Disilylamidokomplexe vom Typ [MX (L 5 )] (M = Ru, Os; X = F, Cl, I, Trifluormethansulfonat (OTf); L 5 = N(SiMe 2 CH 2 PtBu 2 ) 2 ), die in Analogie zu Eisen(II) eine elektronische Intermediate-SpinKonfiguration aufweisen. [9,10] [Ir(H)Cl(C 8 H 13 )(HL 1 )] (3; R = tBu) [13] wird in situ mit Benzochinon (2.5 ¾quiv.) zum türkisfarbenen 1 in Ausbeuten an isoliertem Produkt von bis zu 60 % oxidiert (Schema 2). [14] Im 31 P-NMR-Spektrum von 1 werden keine Signale beobachtet. Die drei breiten Signale im 1 H-NMR-Spektrum sind stark paramagnetisch verschoben und kçnnen den tBu-Substituenten (d = 10.5 ppm) und je einem Satz von Ligand-

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Ein quadratisch‐planarer Ruthenium(II)‐Komplex mit Low‐Spin‐ Konfiguration

Cited by 13 publications

References 31 publications

Square‐Planar Ruthenium(II) Complexes: Control of Spin State by Pincer Ligand Functionalization

Square‐Planar Ruthenium(II) Complexes: Control of Spin State by Pincer Ligand Functionalization

Pseudo‐tetrahedral Rhodium and Iridium Complexes: Catalytic Synthesis of E‐Enynes

Quadratisch‐planare Iridium(II)‐ und Iridium(III)‐Amidokomplexe mit einem PNP‐Pinzettenliganden

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