Metal derivatives of conjugated dienes. Part III. Some cyclohexa- and cyclohepta-dienyliron compounds

Hashmı, Muhammad Alı; Munro, J. D.; Pauson, P. L.; Williamson, Joanne M.

doi:10.1039/j19670000240

Cited by 66 publications

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“…This contrasts with the related additions of pyridines to cation (Ia) where 2-methylpyridine is cu 3 times less reactive than pyridine despite its higher basicity (departure from pyridine Brsnsted plot ca 1.0 log units).6 Adherence of 4-methylimidazole to the Brsnsted equation (3) suggests that this nucleophile employs its nonsterically demanding 5-methyl tautomeric form in addition to (Ia).…”

Section: Pmmentioning

confidence: 76%

“…Acetonitrile (BDH/Aldrich) solvent was distilled in bulk and stored over molecular sieves (3A) under a dinitrogen atmosphere prior to use. 3.19 (overlapping dt's, IH, diene H', J132 = 6.2, J1,6' = J1,6 = 2.4 Hz), 3.06 (overlapping dd, lH, diene H4, J4,5t -3.5, J4,3 -5.5 Hz), 2.65 (septet, lH, diene H6', J6,,6 = 15.8, J6J,5, = 11.0, J6',1 = 4.0 Hz), 1.69 (br d, 1 H, diene H6, J6,6, = 16.0 Hz).…”

Section: Methodsmentioning

confidence: 99%

“…'H n.m.r. (CD3COCD3): 6 9.17 (H2 of Im), 7.92 (H4 of Im), 7.80 (H' of Im), 7.2-7.6 (Ph3C), 5.97 (t, lH, diene H2, J2,, = J2,3 = 5 Hz), 5.86 (br m, lH, diene H3), 5.31 (m, lH, diene H5'), 3.30 (br m, lH, diene HI), 3.24 (br m, 1 H diene H4), 2.8 (diene H6', masked by H20), 1.96 (m, lH, diene H6).…”

Section: Tricarbonyl(l-cy-5-n-tritylirnidazoliocyclohexa-l 3-diene)imentioning

confidence: 99%

“…(CD,CN/2 drops TFA): 6 7.24 (m, Im), 5.82 (diene H2, masked by free Ia peak), 5.69 (t, lH, diene H3, J3,2 -J3,4 -4.5 Hz), 4.82 (dt, lH, diene 2.99 (br t, lH, diene H4, J4,3 -J4,5r -4.5 Hz), 2.64 (septet, lH, diene H", J5,,6, = 11.0, J5,,4 = Jsr36 = 3.4 HZ), 3.22 (br m, IH, diene H'), H6', J6r.6 = 16.1, J6,,5t = 11.0, J G , ,~ = 3.5 HZ), 2.52 ( S , 3 H, Me O f h ) , 1.65 (d, 1H, diene H6, 56.6, = 16 Hz).Tricarbonyl(l-4-~-5-N-methylimidazoliocyclohexa-I , 3-diene)iron tetrafluoroborate (LIIc)cationic adduct as a pale yellow microcrystalline product (78% yield).Calc. for Cl3HI3N2O3FeBF4: C, 40.2; H,3.3; N, 7.2%. Found: C, 38.8; H, 3.3; N, 7.0Yo.I.r.…”

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confidence: 99%

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KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 31 ADDITION OF IMIDAZOLES TO [Fe(CO)₃(1-5-η-DIENYL)]⁺CATIONS

Evans

Kane‐Maguire

Kanitz

1996

Journal of Coordination Chemistry

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Synthetic and spectroscopic studies show that imidazole, 2-methylimidazole, and 4-methylimidazole (BH) react with the dienyl cations [Fe(CO),( 1-5-q-dienyl)]' (Ia-Ic; dienyl = C6H,, 2-MeOC6H6, or C,H,) in CH,CN or acetone solvent via the two-step sequence shown below. kl +BH (I) + BH __+ [Fe(CO),(BH.diene)]+ -[Fe(CO),(B.diene)] + BH2+ k2 (111) (IV) With N-methylimidazole, which contains no ring N-H group, reaction stops at the monocationic adduct (111). In all cases the rate law, kbn = k, [amine] is obeyed. This may be rationalised in terms of rate-determining addition (k,) at the dienyl ring to yield (111), followed where applicable by rapid deprotonation (k2) to yield the final neutral adduct (IV).For attack by imidazole, the rate trend is CsH, > 2-MeOC6H6 > C7H9 (relative rates: 47:4:1), revealing a previous k, value for cation (Lb) to be erroneous. This rate trend, together with the exo-configuration established for adducts (111), support direct addition (k,) of imidazole from above the dienyl ring. The reactivity order 2-methylimidazole > 4-methylimidazole > N-methylimidazole > imidazole is observed towards both cations (la) and (Ib), revealing a strong dependence of rate on nucleophile basicity. Steric effects are less significant than in the related addition of pyridines to these dienyl cations. 30: S. Chapman and L.A.P. Kane-Magurie, J. Chem. SOC., Dalton Trans., 2021 (1 995).

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Section: Pmmentioning

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Section: Tricarbonyl(l-cy-5-n-tritylirnidazoliocyclohexa-l 3-diene)imentioning

confidence: 99%

mentioning

confidence: 99%

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KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 31 ADDITION OF IMIDAZOLES TO [Fe(CO)₃(1-5-η-DIENYL)]⁺CATIONS

Evans

Kane‐Maguire

Kanitz

1996

Journal of Coordination Chemistry

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“…spectra of ( 5 ) (Table 2) show that the basic hydrocarbon skeleton of ( 2) is retained on addition of the phosphine ligands. A full assignment of the spectra, which showed nucleophilic attack at C(3) and C( 14), rather than C (7) and C(lO), was verified by partial deuteriation; the complexes [Fe2(C0)6(q4:q'4-C1 6H 6D2)] (1-D), phonium) Salt [Fe,(CO)6{q4:q'4-C,,Hl 8(PPh,)2}][PF6], ( 5 ) [Fe2(CO)6(q5:q'5-C1 fjH 1 6D2)][pF6]2…”

mentioning

confidence: 99%

Reduction–oxidation properties of organotransition-metal complexes. Part 20. Oxidative and thermolytic cyclopropane ring-opening reactions; X-ray crystal structure of [Fe₂(CO)₆(η⁴:η′⁴-C₁₆H₁₈)]

Connelly¹,

Lucy²,

Mills³

et al. 1985

J. Chem. Soc., Dalton Trans.

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I TS Oxidation of [ Fe,( C O ) , ( T ~~: T ~' ~-C , , H ~~) ] (1 ) with ferrocenium hexafluorophosphate results in regioselective cyclopropane ring-opening and the formation of [Fe,(CO),(q5:q'5-Cl,H18)] *+ (2), a derivative of trans-l,2-bis(cycloheptadienyl)ethylene. The same hydrocarbon ligand is formed w h e n (1) is thermolysed to give the insoluble polymer [{Fe,(CO),(p-C0),(~5:~r5-C,,Hl,)},] (3). A n Xray diffraction study has shown that the regio-and stereo-specificity observed in the formation of (2) and (3) derives from the stereochemistry of (1). The molecule (1) as a whole has near t w ofold symmetry, but this is not crystallographically required. T w o ring systems comprising fused cyclopropane and cyclohepta-lr3-diene fragments are joined b y a single bond between the t w o apical cyclopropane atoms. Four atoms of each C, ring are essentially co-planar, giving an 'envelope' conformation to the ring, and are bonded to an Fe(CO), fragment; the remainder of the C, ring is also planar, and incorporates the two C atoms shared with the C, ring and the CH, group. The C, ring folds away from the metal atom, and there are further folds at the junction with the C, ring and again at the apex of the C, ring, all in the same sense. The C, symmetry thus confers an overall S shape on the dimeric species when viewed along the t w o -f o l d axis. Along the Fe Fe vector, b y contrast, the C, rings are seen nearly edgewise and the two C, rings are almost eclipsed. Crystals of [ Fe,( CO),(q4:q4-C16H,8)] (1) are triclinic, space group P i , and the structure has been refined to R 0.043 for 3 468 reflections measured at 293 K. Complex (3) undergoes metal-metal bond cleavage with iodine to yield [Fe,l,(CO)4(qs:~'5-C,6H,8)] ( 4) which may also be prepared from the reaction of (2) and iodide ion. Triphenylphosphine adds to the terminal carbon atoms, adjacent to the CH, groups, of the dienyl units of (2), giving the bis(phosphonium) salt [Fe,(CO),(q4:qr4-C16H18( PPh,),}] [PF,], (5).The stereospecific oxidative dimerisation of [Fe(CO),(q4cot)] (cot = cyclo-octatetraene) gives [Fe,(CQ),(q':?"-C16H,,)]2+ which reacts with [BH,]-to yield [Fe,(C0)6(q4:q'4-C,,H,,)] (1) (Scheme 1). We now report details3 of the oxidation and thermolysis of (I), to yield CFe2(CQ)6(r15:q'5-C16H 18)12 + (2) and [f Fe2(CO),(~-CQ)2(q5:q'5-C 6H s)>n] (3), respectively; an X-ray diffraction study of (1) has shown that the stereochemistry of the rruns-1,2bis(cycloheptadieny1)ethylene ligands of (2) and (3) derives from that of the 8,8'-bi(bicyclo[5. 1 .O]octa-2,4-diene) ligand of (1). The reactions of (2) with iodide ion and with PPh,, and the reaction of (3) with iodine, are also reported. Results and DiscussionThe addition of two equivalents of [Fe(q-C,H,),][PF,] to a solution of [Fe2(CO),(r74:r7'4-C~6H,8)] ( I ) in CH,CI, gave a white precipitate which, on recrystallisation from nitromethanediethyl ether, was characterised as [Fe,(CO),(q ':q"-C,6H1,)'1. ~~ ~ -~ ~~ ~ ~ * fruns-p-[ 2-5-q:2'-5'q-8.8'-Bi( bicycle[ 5.1 .O]octa-2,4-diene) ] -hexacarbon y ldi-ir...

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Tricarbonyl(cyclohexadienyl)iron Tetrafluoroborate

Tao

2001

Encyclopedia of Reagents for Organic Synthesis

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Metal derivatives of conjugated dienes. Part III. Some cyclohexa- and cyclohepta-dienyliron compounds

Cited by 66 publications

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KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 31 ADDITION OF IMIDAZOLES TO [Fe(CO)₃(1-5-η-DIENYL)]⁺CATIONS

KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 31 ADDITION OF IMIDAZOLES TO [Fe(CO)₃(1-5-η-DIENYL)]⁺CATIONS

Reduction–oxidation properties of organotransition-metal complexes. Part 20. Oxidative and thermolytic cyclopropane ring-opening reactions; X-ray crystal structure of [Fe₂(CO)₆(η⁴:η′⁴-C₁₆H₁₈)]

Tricarbonyl(cyclohexadienyl)iron Tetrafluoroborate

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Metal derivatives of conjugated dienes. Part III. Some cyclohexa- and cyclohepta-dienyliron compounds

Cited by 66 publications

References 0 publications

KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 31 ADDITION OF IMIDAZOLES TO [Fe(CO)3(1-5-η-DIENYL)]+CATIONS

KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 31 ADDITION OF IMIDAZOLES TO [Fe(CO)3(1-5-η-DIENYL)]+CATIONS

Reduction–oxidation properties of organotransition-metal complexes. Part 20. Oxidative and thermolytic cyclopropane ring-opening reactions; X-ray crystal structure of [Fe2(CO)6(η4:η′4-C16H18)]

Tricarbonyl(cyclohexadienyl)iron Tetrafluoroborate

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KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 31 ADDITION OF IMIDAZOLES TO [Fe(CO)₃(1-5-η-DIENYL)]⁺CATIONS

KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 31 ADDITION OF IMIDAZOLES TO [Fe(CO)₃(1-5-η-DIENYL)]⁺CATIONS

Reduction–oxidation properties of organotransition-metal complexes. Part 20. Oxidative and thermolytic cyclopropane ring-opening reactions; X-ray crystal structure of [Fe₂(CO)₆(η⁴:η′⁴-C₁₆H₁₈)]