Optically Active Transition Metal Complexes. 128 [1] Synthesis, Characterization and Molecular Structures of Cycloheptatrienyl-Iminphos-Molybdenum Complexes Differing Only in the Metal Configuration

Brunner, Henri; Klankermayer, Jürgen; Zabel, Manfred

doi:10.1002/1521-3749(200211)628:11<2264::aid-zaac2264>3.0.co;2-3

Cited by 5 publications

(2 citation statements)

References 19 publications

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“…Chiral-at-metal complexes derive their asymmetry from the arrangement of ligands around the metal center . Recent examples of chiral-at-metal organometallic complexes include half-sandwich complexes with a pseudo-tetrahedral geometry around the metal similar to carbon …”

Section: Introductionmentioning

confidence: 99%

Chiral-at-Metal Osmium(VI) Phosphine Complexes

Pool

Shapley

2004

Organometallics

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The chiral-at-metal osmium complex [N(n-Bu)4][cis-Os(N)(CH2SiMe3)PhCl2] results from series of alkylation and protonation reactions from [N(n-Bu)4][Os(N)Cl4]. (S,S)-Chiraphos displaces a chloride from this complex to produce two isomers of Os(N)(CH2SiMe3)PhCl((S,S)-chiraphos) with different configurations at osmium. 31P NMR spectroscopy indicates that one isomer has a phosphorus donor from the chiraphos ligand trans to the nitride, while the other has chloride in this position. Molecular mechanics calculations suggest that the axial phosphine isomer has an S configuration at osmium. This isomer reversibly loses an additional chloride ion and can be separated from the isomer with the opposite configuration by the careful addition of AgSbF6. The diastereomers [SbF6][(S)-Os(N)(CH2SiMe3)Ph((S,S)-chiraphos)] and [SbF6][(R)-Os(N)(CH2SiMe3)Ph((S,S)-chiraphos)] can be isolated separately. The two isomers of [SbF6][Os(N)(CH2SiMe3)Ph((R,R)-chiraphos)] are enantiomers to those of [SbF6][Os(N)(CH2SiMe3)Ph((S,S)-chiraphos)]. The molecular structures of acetonitrile adducts [SbF6][(S)-Os(N)(CH2SiMe3)Ph((S,S)-chiraphos)(NCMe)] and [SbF6][(R)-Os(N)(CH2SiMe3)Ph((S,S)-chiraphos)(NCMe)], from a crystal containing both isomers, show equatorial, chelating (S,S)-chiraphos ligands with acetonitrile trans to the nitride in each.

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Section: Introductionmentioning

confidence: 99%

Chiral-at-Metal Osmium(VI) Phosphine Complexes

Pool

Shapley

2004

Organometallics

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“…In view of the growing number of well-characterized 16-electron cyclopentadienyl-ruthenium complexes, it is surprising that no analogous half-sandwich cycloheptatrienyl-molybdenum complexes have been reported to date, although the similarity between the isoelectronic and isolobal fragments [(η 5 -C 5 R 5 )Ru] and [(η 7 -C 7 H 7 )Mo] is well recognized. – The steric requirements of the C 7 H 7 (Cht) ligand (cone angle ≈ 154°) make comparison with the C 5 Me 5 (Cp*) system (cone angle ≈ 142°) particularly appropriate, and it could clearly be demonstrated that complexes of the 16-electron [(η 7 -C 7 H 7 )MoL 2 ] auxiliary exhibit reactivity patterns analogous to those of [(η 5 -C 5 Me 5 )RuL 2 ] systems. , In this contribution, we present the synthesis and structural characterization of stable cationic 16-electron molybdenum complexes of the type [(η 7 -C 7 H 7 )Mo(BL R )] + (R = Me, i Pr) containing the neutral 1,2-bis(imidazolin-2-imino)ethane ligands BL Me and BL i Pr and compare their properties with those of their [(η 5 -C 5 Me 5 )Ru(BL R )] + congeners …”

Section: Introductionmentioning

confidence: 99%

Synthesis and Reactivity of 16-Electron Cycloheptatrienyl-Molybdenum(0) Complexes with Bis(imidazolin-2-imine) Ligands

et al. 2008

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The reaction of the ligands 1,2-bis(1,3-diisopropyl-4,5-dimethylimidazolin-2-imino)ethane (BL iPr ) and 1,2-bis(1,3,4,5-tetramethylimidazolin-2-imino)ethane (BL Me ) with the cycloheptatrienyl-molybdenum complex [(η 7 -C 7 H 7 )Mo(CH 3 CN) 3 ]X (X ) BF 4 , PF 6 ) leads to acetonitrile substitution and formation of stable 16-electron half-sandwich complexes (η 7 -C 7 H 7 )Mo(BL iPr )]BF 4 , [1]BF 4 , and [(η 7 -C 7 H 7 )Mo(BL Me )]X, [2]X (X ) BF 4 , PF 6 ), two of which could be crystallographically characterized to reveal undistorted two-legged piano stool geometries. Cyclovoltammetric studies exhibit very negative redox potentials of E°) -1.095 V and E°) -1.138 V versus the ferrocene/ferrocenium couple (0 V), indicative of very electron-rich metal complexes. Oxidation of [2]X with (η 7 -C 7 H 7 )BF 4 or [Fe(η 5 -C 5 H 5 ) 2 ]PF 6 furnished the Mo(I) complexes of general formula [(η 7 -C 7 H 7 )Mo(BL Me )(CH 3 CN)]X 2 , [3]X 2 (X ) BF 4 , PF 6 ), which display a three-legged piano stool geometry in the solid state by coordination of one additional acetonitrile molecule to molybdenum. The same geometry is observed upon reaction of [1]BF 4 and [2]PF 6 with 2,6dimethylphenyl isocyanide (XyNC) to afford the isocyanide complexes [1(CNXy)]BF 4 and [2(CNXy)]PF 6 . Their CN stretching vibrations are observed at 2041 and 2030 cm -1 , confirming the electron richness and strong π-electron-releasing capability of the molybdenum-imine moiety.

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Molybdenum Compounds with CO or Isocyanides

Tamm

Baker

2007

Comprehensive Organometallic Chemistry III

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Optically Active Transition Metal Complexes. 128 [1] Synthesis, Characterization and Molecular Structures of Cycloheptatrienyl-Iminphos-Molybdenum Complexes Differing Only in the Metal Configuration

Cited by 5 publications

References 19 publications

Chiral-at-Metal Osmium(VI) Phosphine Complexes

Chiral-at-Metal Osmium(VI) Phosphine Complexes

Synthesis and Reactivity of 16-Electron Cycloheptatrienyl-Molybdenum(0) Complexes with Bis(imidazolin-2-imine) Ligands

Molybdenum Compounds with CO or Isocyanides

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