Bis(η-cyclopentadienyl)molybdenum chemistry: synthesis and reactions of ring-functionalised compounds

Baretta, A.; Chong, Kenneth S.; Cloke, F. Geoffrey N.; Feigenbaum, Alexander; Green, Malcolm L. H.

doi:10.1039/dt9830000861

Cited by 24 publications

(11 citation statements)

References 4 publications

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“…3.5 ppm). [15] Such chemical shift values are in agreement with those in compound 6, which has two methylene resonances at δ = 2.22-2.12 ppm and δ = 3.57-3.37 ppm. However, since the new compound does not have any resonances in the δ = 3.5 ppm region, the formation of structure 9Ј is most unlikely.…”

Section: Cyclopentadienyl Complexessupporting

confidence: 76%

“…[14] When Mo atoms are used for this purpose, the resulting ansa complex [Mo(η 5 -C 5 H 4 CH 2 -η 1 -CH 2 ) 2 ] enables the introduction of various substituents containing functional groups onto the cyclopentadienyl rings. [15] The resulting products are functionalized equally on both rings. The problem of functionalizing only one of cyclopentadienyl rings could probably be solved by the use of the ansa compound [Mo(η 5 -C 5 H 4 CH 2 -η 1 -CH 2 )(η 4 -C 5 H 6 )(CO)] [16] that was previously synthesized from [Mo(η 5 -C 5 H 4 CH 2 -η 1 -CH 2 )(CO) 3 ] [17] and cyclopentadiene through a photochemical route.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, Characterization and Stability of Spirodiene Complexes of Molybdenum(II): New Route to ansa‐Molybdenocene and Ring‐Functionalized Molybdenocene Compounds

2007

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The reactions of [Mo(CO)2(Cp)(NCCH3)2][BF4] (1) with spiro[2.4]hepta‐4,6‐diene and spiro[4.4]nona‐1,3‐diene give the complexes [Mo{η4‐C5H4(CH2)2}(CO)2(Cp)][BF4] (3) and [Mo{η4‐C5H4(CH2)4}(CO)2(Cp)][BF4] (4), respectively. [Mo{η4‐C5H4(CH2)2}(CO)2(Cp)][BF4] (3) is stable towards ring opening at room temperature, but its formation is accompanied by small amounts of ring‐opening products [Mo(η5‐C5H4CH2‐η1‐CH2)(CO)(Cp)][BF4] (5) and [Mo{η5‐C5H4(CH2)2‐η1‐CO}(CO)(Cp)][BF4] (6). With 1,1‐dimethyl‐spiro[2.4]hepta‐4,6‐diene, two isomers with the formula [Mo{η4‐C5H4CH2C(CH3)2}(CO)2(Cp)][BF4] are formed (7 and 8). While the endo‐isomer 7 is stable towards ring opening, the exo‐isomer 8 slowly rearranges to the ring‐opened product [Mo{η5‐C5H4C(CH3)2CH2‐η1‐CO}(CO)(Cp)][BF4] (9). The reaction of [Mo(CO)2(Ind)(NCCH3)2][BF4] (2) with spiro[4.4]nona‐1,3‐diene also gives the diene coordinated species [Mo{η4‐C5H4(CH2)4}(CO)2(Ind)][BF4] (11), which is the first example of a structurally characterized, coordinated, unsubstituted spirodiene. In contrast, reaction of 2 with spiro[2.4]hepta‐4,6‐diene leads directly to the ansa‐cyclopentadienyl complex [Mo(η5‐C5H4CH2‐η1‐CH2)(CO)(Ind)][BF4] (12). Reaction of 12 with bromine or iodine leads to the formation of Cp‐substituted molybdenocene derivatives [Mo{η5‐C5H4(CH2)2X}(CO)(Ind)X][BF4] (13: X = Br, 14: X = I). The compounds [Mo(η5‐C5H4CH2‐η1‐CH2)(CO)(Ind)][BF4] (12) and [MoBr{η5‐C5H4(CH2)2Br}(CO)(Ind)][Br]·0.5H2O (13a) were structurally characterized, and they open the way to new functionalized molybdenocene complexes that have biological applications.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Section: Cyclopentadienyl Complexessupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization and Stability of Spirodiene Complexes of Molybdenum(II): New Route to ansa‐Molybdenocene and Ring‐Functionalized Molybdenocene Compounds

2007

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“…So far only a few ring-substituted molybdenocenes containing substituents other than alkyl or silyl have been described. All of them were prepared from [(C 5 H 4 CH 2 CH 2 I) 2 MoI 2 ] using the nucleophilic substitution of iodine from the −CH 2 CH 2 I pendant groups . In this work, we have used other synthetic procedures to extend the group of ring-functionalized compounds to those containing ether and carboxylic acid ester groups in the side chain.…”

Section: Discussionmentioning

confidence: 99%

“…For this purpose, compounds with η 5 :η 1 -cyclopentadiendiylethyl ligands seem to be more efficient because their reaction with iodine gives compounds with iodoethyl-substituted cyclopentadienyl rings . A variety of functionalized compounds is then available through the nucleophilic substitution of iodide …”

Section: Introductionmentioning

confidence: 99%

Ring-Functionalized Molybdenocene Complexes

et al. 2009

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The synthesis and characterization of new ring-functionalized molybdenocene derivatives [CpCp′Mo(CO) 2 ] 2+ and [CpCp′Mo(CO)Br] + (η 5 -C 5 H 4 R; R ) CH 2 CH 2 OMe, CH 2 CH 2 COOEt, CH 2 CH 2 OOCMe, COOMe) are reported. Three alternative routes were used to assemble the CpCp′Mo moiety. Following route I, the unsubstituted precursor [CpMo(CO) 2 (NCMe) 2 ] + reacts with substituted cyclopentadienes (Cp′H) to give after oxidation dicationic compounds [CpCp′Mo(CO) 2 ] 2+ . Alternatively, route II introduces the substituent in the first reaction step upon the synthesis of [Cp′Mo(CO) 2 (NCMe) 2 ] + . In this case, the bis-cyclopentadienyl compounds [CpCp′Mo(CO) 2 ] 2+ were obtained after reaction with cyclopentadiene (C 5 H 6 ) and subsequent oxidation. The NMR spectroscopic measurements prove that the reaction pathways of routes I and II go through different intermediates. The bromo complexes [CpCp′Mo(CO)Br] + were synthesized using route III. Reaction of [Cp′Mo(CO) 2 (NCMe) 2 ] + with C 5 H 5 SiMe 3 gives hydride complexes [CpCp′Mo(CO)H] + . Appropriate bromo complexes were obtained upon reaction with bromine. The ring-functionalized bis-cyclopentadienyl molybdenum(IV) compounds and their monocyclopentadienyl precursors were characterized by spectroscopic methods. Structures of, [(η 5 -C 5 H 4 SiMe 3 )Mo(CO) 2 (NCMe) 2 ][BF 4 ], and [CpMo(η 5 -C 5 H 4 COOMe)(CO)H][BF 4 ] were determined with X-ray diffraction analysis.

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“…The cycloalkyl bis(methanesulfonates) were synthesized from their respective diols using published procedures 13a. (Cyclopentane‐ and cyclohexanediol purchased from Aldrich and used without further purification, cycloheptane‐ and cyclooctanediol were synthesized from the respective olefins via KMnO 4 dihydroxilation using previously reported procedures13b). The spiro‐annulated compound spiro[2,4]hepta‐4,6‐diene ( 1e ) and the metal precursors [Mo(CO) 3 (tach)] and [W(CO) 3 (tach)] were synthesized according to published procedures 14.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Catalytic Applications of ansa Compounds with Cycloalkyl Moieties as Bridging Units: A Comparative Study

et al. 2010

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Abstract:The molybdenum and tungsten compounds (MoA C H T U N G T R E N N U N G {h-CH}(CO) 3 ) (2a, 3a n = 3; 2b, 3b n = 4; 2c, 3c n = 5; 2d, 3d n = 6) were synthesized by reacting the spiro-bicyclic compounds 1a-d with theNMR spectroscopy, as well as X-ray diffraction studies, confirm the formation of an intramolecular ansa bridge. The complexes display a good stability in the solid state (stable up to 180 8C under air, as determined by thermogravimetric studies) and are highly active catalysts at room temperature (molybdenum compounds) or above (tungsten compounds) in olefin epoxidation. In the case of cyclooctene as substrate, TOFs up to ca. 11800 h À1 are obtained. Moreover, most of the catalysts described here display a high selectivity in the epoxidation of cis-and transstilbene. In addition, the novel complexes were compared with previously synthesized related compounds, at least matching their catalytic performances.

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Bis(η-cyclopentadienyl)molybdenum chemistry: synthesis and reactions of ring-functionalised compounds

Cited by 24 publications

References 4 publications

Synthesis, Characterization and Stability of Spirodiene Complexes of Molybdenum(II): New Route to ansa‐Molybdenocene and Ring‐Functionalized Molybdenocene Compounds

Synthesis, Characterization and Stability of Spirodiene Complexes of Molybdenum(II): New Route to ansa‐Molybdenocene and Ring‐Functionalized Molybdenocene Compounds

Ring-Functionalized Molybdenocene Complexes

Synthesis and Catalytic Applications of ansa Compounds with Cycloalkyl Moieties as Bridging Units: A Comparative Study

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