The preparation of multimetallic complexes using sterically bulky N-centred tripodal dialkyl phosphino ligands

Miller, Philip W.; White, Andrew J. P.

doi:10.1016/j.jorganchem.2010.01.017

Cited by 27 publications

(33 citation statements)

References 44 publications

(58 reference statements)

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“…Although the bond angles at the methylene bridge carbon could not support apical atom coordination, it appears that these atoms should not be considered innocent, and may impose considerable electronic contributions to the overall structure of the complex. The steric bulk of the phosphines was increased in two new derivatives by replacement of the phenyl substituents at phosphorus with cyclohexyl (N(CH 2 PCy 2 ) 3 , NP 3 Cy , 118) and tert-butyl groups (N(CH 2 P t Bu 2 ) 3 , NP 3 tBu , 119) [49]. Additionally, these ligands were synthesized via a conveniently air-stable phosphonium intermediate, which improved the yield and allowed long-term storage of otherwise air-sensitive phosphines.…”

Section: Nitrogen (N(ch 2 Pr 2 ) 3 )mentioning

confidence: 99%

“…It was argued that this was due to the increased steric demand around the metal center and demonstrated via space-filling models this increase in steric encumberment. The pendant arm was used to coordinate to different metals (gold (122), platinum (123 and 124) and silver (125)), affording hetero-multimetallic complexes (Scheme 20) [49].…”

Section: Nitrogen (N(ch 2 Pr 2 ) 3 )mentioning

confidence: 99%

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Beyond Triphos – New hinges for a classical chelating ligand

Phanopoulos

Miller

Long

2015

Coordination Chemistry Reviews

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Branched triphosphine ligands have been less widely studied than mono-and bidentate analogues. The most studied ligand of this type is Triphos Ph (CH 3 C(CH 2 PPh 2 ) 3 ). Substitution of the apical C-CH 3 moiety with boron, silicon, tin, nitrogen or phosphorus fragments has generated a new family of ligands, in some cases displaying varying coordination chemistry and reactivity to the parent carbonbased system. This review includes the synthetic strategies implemented to afford these ligands, as well as derivatives by way of varying the phosphine substituents. Although not exhaustive, relevant types of reported complexes featuring these ligands are discussed, as well as their reactivity and catalytic applications. Through critical analysis, common themes and chemical trends across this family of apical heteroatomic, branched triphosphines can be identified, leading to improvements in current chemical applications, as well as new areas that remain underdeveloped.

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Section: Nitrogen (N(ch 2 Pr 2 ) 3 )mentioning

confidence: 99%

Section: Nitrogen (N(ch 2 Pr 2 ) 3 )mentioning

confidence: 99%

Beyond Triphos – New hinges for a classical chelating ligand

Phanopoulos

Miller

Long

2015

Coordination Chemistry Reviews

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“…N--TriPhos Ph was prepared as previously reported [26] following a modified procedure to that described by Markl et al [27]. The bis(hydroxymethyl)diphenylphosphonium chloride [28] was found to be a convenient starting material for the preparation of N--TriPhos Ph .…”

Section: Ligand Synthesismentioning

confidence: 99%

Ruthenium-catalysed hydrogenation of esters using tripodal phosphine ligands

Hanton

Tin

Boardman

et al. 2011

Journal of Molecular Catalysis A: Chemical

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“…[b] 0.1 mol % of catalyst; catalyst concentration 0.001 m, 5 bar H 2 pressure; conversions were > 99 % after 5 h, ee determined by chiral HPLC. [c] C 3 -symmetric DMP (11), pseudo-C 2 -symmetric DPP (12) and heterodinuclear DPP (13 a-c) rhodium complexes: The structurally different catalyst 11, containing the C 3 -symmetric dimethylphospholane ligand 7, was also tested in the hydrogenation of the five olefinic substrates. Because the precatalyst is a pentacoordinate 18-electron species (Figure 4), decoordination of one phospholane unit may be required as the first step of the catalytic reaction.…”

Section: Entrymentioning

confidence: 99%

“…Indeed, the treatment of a phosphonium salt with a base followed by addition of a nucleophile, typically an amine (including ammonia and primary or secondary amines) affords tri-, bi-or monodentate ligands (Scheme 1). [9] In this way, achiral mono-, [10] bi- [7,11] and tridentate [12] ligands were synthesised by combining two modules: the phosphane unit and the amine group. It also allowed the introduction of diphosphanes into dendrimers, [13] calixarenes, [14] proteins [15] and solid supports, [16] as well as other forms of derivatisation.…”

Section: Introductionmentioning

confidence: 99%

Stitching Phospholanes Together Piece by Piece: New Modular Di‐ and Tridentate Stereodirecting Ligands

Lloret‐Fillol¹,

Kruckenberg²,

Scherl³

et al. 2011

Chemistry A European J

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The modular one-pot synthesis of a large family of bi- and tridentate 2,5-dimethyl- and 2,5-diphenyl-substituted phospholanes employs air-stable chiral phospholanium chloride salts and primary amines or NH(4)Cl as starting materials. These were transformed into the C(2)-symmetric dimethyl- and diphenylphospholane ligands, which reacted with [Rh(cod)(2)]BF(4) (cod=1,5-cyclooctadiene) to yield the rhodium complexes [Rh(L)(cod)]BF(4) (L=bisphospholane ligands). The corresponding trisphospholane complexes, 11 and 12, were obtained in high yields (81 and 92%, respectively), and fully characterised by NMR spectroscopy, mass spectrometry and elemental analysis. Whilst in the C(3)-symmetric complex 11, containing the tridentate 2,5-dimethylphospholane, the ligand is bound symmetrically, different coordination behaviour was found for the diphenyl-substituted complex 12, in which the coordination of only two of the three phospholane moieties to the metal centre was observed. A DFT study at the B3PW91 level established minimum energy structures consistent with experimental findings in solution and in the solid state. The non-coordinated phospholane unit present in 12 allowed further modification of the complex through the coordination of Au(I)-X (X=Cl, C(6)F(5) and tris(trifluoromethyl)phenyl ((F)Mes)) fragments to the pendant phosphane. To investigate the potential of the new ligands, the enantioselective hydrogenation of a series of prochiral olefins as benchmark substrates, using isolated Rh complexes as catalysts, was studied. The substrates included methyl esters of three dehydro-α-acetamido acids and two itaconic acid derivatives. In general good to excellent enantioselectivities (of up to >99% ee) were observed. Ligand backbone modification by coordination of bulky Au-X substituents to the free phospholane unit in complex 12 led to an outstanding enhancement of the catalyst performance and there was a clear correlation between the properties of the complex periphery and the enantioselectivity.

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The preparation of multimetallic complexes using sterically bulky N-centred tripodal dialkyl phosphino ligands

Cited by 27 publications

References 44 publications

Beyond Triphos – New hinges for a classical chelating ligand

Beyond Triphos – New hinges for a classical chelating ligand

Ruthenium-catalysed hydrogenation of esters using tripodal phosphine ligands

Stitching Phospholanes Together Piece by Piece: New Modular Di‐ and Tridentate Stereodirecting Ligands

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