Functionalized Ether Derivatives of HOCH2C(CH2PPh2)3 and Related Tripod Ligands – Synthesis and Coordination Chemistry

Schober, P.; Soltek, Rainer; Hüttner, Gottfried; Zsolnai, László; Heinze, Katja

doi:10.1002/(sici)1099-0682(199810)1998:10<1407::aid-ejic1407>3.0.co;2-j

Cited by 17 publications

(6 citation statements)

References 28 publications

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“…To ensure that the ligand remains intact during the reaction, we first coordinated it to the molybdenum carbonyl precursor and then connected the complex to the octyl‐TATA platform. In this way, the phosphine units are protected by coordination to the molybdenum center . An additional advantage of this approach is the fact that it avoids metalation of surface‐deposited ligands, which may be associated with further problems.…”

Section: Resultsmentioning

confidence: 99%

Influence of a Metal Substrate on Small‐Molecule Activation Mediated by a Surface‐Adsorbed Complex

Schlimm

Stucke

Flöser

et al. 2018

Chemistry A European J

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Activating small molecules with transition metal complexes adsorbed on metal surfaces is a novel approach combining aspects of homogeneous and heterogeneous catalysis. In order to study the influence of an Au(111) substrate on the activation of the small-molecule ligand carbon monoxide, a molybdenum tricarbonyl complex containing a PN P pincer ligand was synthesized and investigated in the bulk, in solution, and adsorbed on an Au(111) surface. By means of a platform approach, a perpendicular orientation of the molybdenum complex was achieved and confirmed by IRRAS and NEXAFS. By using vibrational spectroscopy (IR, Raman, IRRAS) coupled to DFT calculations, the influence of the metal substrate on the activation of the CO ligands bound to the molybdenum complex was determined. The electron-withdrawing behavior of gold causes an overall shift of the CO stretching vibrations to higher frequencies, which is partly compensated by dynamic charge transfer from the substrate to the molybdenum center, which increases its (dynamic) polarizability.

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Section: Resultsmentioning

confidence: 99%

Influence of a Metal Substrate on Small‐Molecule Activation Mediated by a Surface‐Adsorbed Complex

Schlimm

Stucke

Flöser

et al. 2018

Chemistry A European J

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“…The most commonly studied tripodal phosphines are 1,1,1-tris(diphenylphosphinomethyl)ethane (CH 3 C(CH 2 PPh 2 ) 3 , triphos Ph ) and its derivatives; these analogues mostly feature changes to the arm length between the apical carbon and phosphine or variance of the phosphine itself. Triphos-type ligands have been shown to coordinate to a wide range of early and late transition metals, − some of which have been evaluated for catalytic activity. Early examples include Rh-triphos Ph complexes used for hydrogenation and hydroformylation of various alkenes or the hydrogenation of quinoline, an important impurity found in fossil fuels that requires degradation .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Reactivity of Ruthenium Hydride Complexes of N-Centered Triphosphine Ligands

et al. 2014

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The reactivity of the novel tridentate phosphine ligand N(CH2PCyp2)3 (N-triphos(Cyp), 2; Cyp = cyclopentyl) with various ruthenium complexes was investigated and compared that of to the less sterically bulky and less electron donating phenyl derivative N(CH2PPh2)3 (N-triphos(Ph), 1). One of these complexes was subsequently investigated for reactivity toward levulinic acid, a potentially important biorenewable feedstock. Reaction of ligands 1 and 2 with the precursors [Ru(COD)(methylallyl)2] (COD = 1,5-cycloocatadiene) and [RuH2(PPh3)4] gave the tridentate coordination complexes [Ru(tmm){N(CH2PR2)3-κ(3)P}] (R = Ph (3), Cyp (4); tmm = trimethylenemethane) and [RuH2(PPh3){N(CH2PR2)3-κ(3)P}] (R = Ph (5), Cyp (6)), respectively. Ligands 1 and 2 displayed different reactivities with [Ru3(CO)12]. Ligand 1 gave the tridentate dicarbonyl complex [Ru(CO)2{N(CH2PPh2)3-κ(3)P}] (7), while 2 gave the bidentate, tricarbonyl [Ru(CO)3{N(CH2PCyp2)3-κ(2)P}] (8). This was attributed to the greater electron-donating characteristics of 2, requiring further stabilization on coordination to the electron-rich Ru(0) center by more CO ligands. Complex 7 was activated via oxidation using AgOTf and O2, giving the Ru(II) complexes [Ru(CO)2(OTf){N(CH2PPh2)3-κ(3)P}](OTf) (9) and [Ru(CO3)(CO){N(CH2PPh2)3-κ(3)P}] (11), respectively. Hydrogenation of these complexes under hydrogen pressures of 3-15 bar gave the monohydride and dihydride complexes [RuH(CO)2{N(CH2PPh2)3-κ(3)P}] (10) and [RuH2(CO){N(CH2PPh2)3-κ(3)P}] (12), respectively. Complex 12 was found to be unreactive toward levulinic acid (LA) unless activated by reaction with NH4PF6 in acetonitrile, forming [RuH(CO)(MeCN){N(CH2PPh2)3-κ(3)P}](PF6) (13), which reacted cleanly with LA to form [Ru(CO){N(CH2PPh2)3-κ(3)P}{CH3CO(CH2)2CO2H-κ(2)O}](PF6) (14). Complexes 3, 5, 7, 8, 11, and 12 were characterized by single-crystal X-ray crystallography.

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“…The synthesis of the functionalized phosphine tripods is based in part on the previous reports by Huttner and co-workers in this field. 9- 13 The starting material is pentaerythritol (1) which is a cheap basic chemical which possesses a functionalized neopentane structure and thus appears to be well suited for the synthetic objective. The four hydroxyl functions in 1 are chemically equivalent, and in order to attach a linker group to only one of these, it had to be differentiated with respect to the others.…”

Section: Synthesis Of the Tripodal Phosphine Ligand Hmentioning

confidence: 99%

“…C-C multiple bonds) 8 or the fact that the phosphino groups are introduced at a very early stage of the reaction sequence, making subsequent work up more difficult. 9- 13 In particular, if expensive (chiral) phosphino functions are to be introduced in an early reaction step of the synthetic pathway, 14 the loss in phosphine during the overall sequence may be considerable. We recently developed a strategy, in which the phosphine is introduced in the final step of the ligand-linker synthesis which was applied to the synthesis of a tripodal phosphine containing an ether-alcohol function in the ligand backbone.…”

Section: Introductionmentioning

confidence: 99%

Tridentate phosphine ligands with novel linker-units

Findeis

Gade

2002

Dalton Trans.

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Functionalized Ether Derivatives of HOCH2C(CH2PPh2)3 and Related Tripod Ligands – Synthesis and Coordination Chemistry

Cited by 17 publications

References 28 publications

Influence of a Metal Substrate on Small‐Molecule Activation Mediated by a Surface‐Adsorbed Complex

Influence of a Metal Substrate on Small‐Molecule Activation Mediated by a Surface‐Adsorbed Complex

Synthesis, Characterization, and Reactivity of Ruthenium Hydride Complexes of N-Centered Triphosphine Ligands

Tridentate phosphine ligands with novel linker-units

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