Transition Metal Complexes of Cyclopentadienylides and Pentafulvenes

Zdanovich, Valeriya I; Seitembetova, A Zh; Setkina, V. N.

doi:10.1070/rc1982v051n07abeh002889

Cited by 9 publications

(5 citation statements)

References 4 publications

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“…The diferrocenylmethylium ion has been structurally investigated, showing a very significant bending of the exocyclic C–C bonds toward the iron atoms (17.7–19.9°) . This is in accord with structures of fulvene complexes, in which the exocyclic double bond is coordinated at the metal atom: − for example, tricarbonyl(fulvene)chromium(0) . In this context a recent structural investigation of ferrocenylboranes, which are isoelectronic with ferrocenylcarbenium ions, revealed a corresponding bending of the C–B bonds toward the iron atom .…”

Section: Resultsmentioning

confidence: 69%

“…13 C NMR (100.6 MHz, acetoned 6 , APT): δ 14.1 (−, CH 3 ), 14.3 (−, CH 3 ), 43.6 (+, C-2), 59.0 (+, CH 2 CH 3 ), 59.6 (+, CH 2 CH 3 ), 86.1(q, −, 4 J C,F = 3.3 Hz, C-5), 89.1(−, C-4), 91.6 (−, C-3), 94.1 (d, +, 2 J C,F = 37.6 Hz, C-6), 104.8 (+, C-1), 110.8 (+, C-2a), 127.2 (q, +, 1 J C,F = 273 Hz, CF 3 ), 143.2 (+, C-6a), 230.9 (+, CO). MS (70 eV): m/z (%) 396 (44) [M + ], 340 (33) [M − 2CO], 312 (72) [M − CO], 267 (24), 235 (49), 215 (18), 196 (100) (53), 145 (30), 120 (27), 102 (14), 75 (6), 52 (12) (7). At 0 °C half-concentrated hydro-chloric acid (150 mL) was added to rac-6 (4.0 g, 10.1 mol) in the dark.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…13 C NMR [125.8 MHz, acetone-d 6 ]: δ 67.9 (CH 2 ), 68.8 (CH 2 ), 88.3 (C-6), 92.4 (d, 3 J C,F = 3.0 Hz, C-4), 92.9 (d, 2 J C,F = 39.5 Hz, C-3), 106.4 (C6a), 121.7 (C-2), 123.6 (d, 1 J C,F = 272.1 Hz, CF 3 ), 124.3 (d, 4 J C,F = 1.4 Hz, C-5), 134.8 (C-2a), 190.5 (C-1), 228.2 (CO) ppm. MS: m/z (%) 380 (13) [M + ], 352 (19) [M + − CO], 324 (16) [M + − 2CO], 296 (73) [M + − 3CO], 277 (10) [M + − 3CO − F], 268 (37) [M + − 4CO], 225 (12), 216 (17) [M + − 4CO − Cr], 196 (100) [(F 3 CC 6 H 3 Cr) + ], 172 (36), 162 (38), 155 (11), 150 (54), 144 (38), 134 (24), 125 (56), 115 (19), 106 (95) [(FCC 6 H 3 ) + ], 103 (50), 87 (78) [C 7 H 3 ) + ], 75 (53) Unsuccessful Attempts toward 1,1,2,2-Tetramethoxy-3-(trifluoromethyl)benzocyclobutene (32). (a) At 0 °C trimethoxymethane (0.6 mL, 5.0 mmol) was added to 6-(trifluoromethyl)benzocyclobutenedione (10; 0.10 g, 0.5 mmol) in methanol (1 mL).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Trifluoromethyl-Substituted Benzocyclobutenone and Benzocyclobutenedione: The Structure Anomaly of (Benzocyclobutenedione)tricarbonylchromium Complexes

et al. 2019

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The syntheses of methoxy- and trifluoromethyl-substituted benzocyclobutenone and benzocyclobutenedione tricarbonylchromium complexes are described. As with the unsubstituted complex, a route via the respective acetals was used. However, attempts to hydrolyze rac-tricarbonyl[1,2-bis(ethylenedioxy)-3-(trifluoromethyl)benzocyclobutene]chromium(0) (rac-12) resulted in only a single hydrolysis and led to rac-tricarbonyl{η6-[2-(ethylendioxy)-3-(trifluoromethyl)benzocyclobutenone]}chromium(0) (rac-14) with different regioselectivity in comparison to the respective reaction of the methoxy-substituted derivative. The synthesis of the desired rac-tricarbonyl[3-(trifluoromethyl)benzocyclobutenedione]chromium(0) (rac-13) was finally achieved by a route via an acyclic diacetal. Compounds were characterized spectroscopically and in a number of cases also by crystal structure analyses. The unusual bending of the annelated cyclobutenedione ring toward the tricarbonylchromium moiety was observed for rac-tricarbonyl-[η6-(methoxybenzocyclobutenedione)chromium(0) (rac-4) as well. To gain more insight into the unusually large bending of the annelated cyclobutenedione or cyclobutenone rings toward the tricarbonylchromium group in some of the studied compounds, we also performed density functional theory (DFT) calculations. In general, the gas-phase DFT optimized structure parameters show good agreement with the crystal structure data, indicating that the cyclobutenedione or cyclobutenone ring bending is a molecular rather than a crystal-packing effect. The DFT optimized structure data also show that annelated cyclobutenedione rings bend more strongly toward the tricarbonylchromium group than do their cyclobutenone analogues. Moreover, the staggered conformation of the tricarbonylchromium group favors larger bending angles. Topological analyses of the electron density of the studied (arene)tricarbonylchromium complexes suggest that the cyclobutenedione ring bending originates from the bending of π orbitals of the arene ring toward the tricarbonylchromium group.

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Section: Resultsmentioning

confidence: 69%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

See 1 more Smart Citation

Trifluoromethyl-Substituted Benzocyclobutenone and Benzocyclobutenedione: The Structure Anomaly of (Benzocyclobutenedione)tricarbonylchromium Complexes

et al. 2019

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“…Except for constrained-geometry complexes with a cyclopentadienylphosphazene ligand, rare-earth Cp complexes with electron-withdrawing substituents at the Cp moiety are, to our knowledge, unknown so far. In this respect, cyclopentadienylides, − e.g. A – C − and 1 (Scheme ), are a very interesting class of electron-poor Cp ligands.…”

Section: Introductionmentioning

confidence: 99%

An Ylidic Cp and its Scandium Complexes in Equilibrium

Mazzotta

Kunz

2021

Organometallics

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Scandium complexes bearing a C-ylidic, electron-deficient Cp ligand are presented by starting from [ScCl 3 (thf) 3 ]. As ylidic ligands do not require salt metathesis, the coordination of the Cp ligand is realized by mere substitution of the tetrahydrofuran ligands. In acetonitrile an equilibrium among the free ligand, the half-sandwich complex, and the cationic metallocene with its tetrachloridoscandate counterion is observed via NMR spectroscopy. This equilibrium is fully confirmed by 1 H and 45 Sc NMR EXSY experiments. In the absence of coordinating solvents, the selective formation of all compounds of the equilibrium has been achieved, and the structures have been confirmed by NMR spectroscopy and X-ray structure analysis. Especially 45 Sc NMR spectroscopy reveals signals with characteristic chemical shifts for the half-sandwich complex and the metallocene. With scandium triflate the corresponding scandocene is also accessible.

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“…After the discovery of ferrocene in 1951, , metal complexes of various Cp ylides were also reported. ,− The group 6 tricarbonyl Cp complexes of fulvenes, pyridinium cyclopentadienylides, phosphonium cyclopentadienylides, − and sulfonium cyclopentadienylides , as well as of arenes and cyclopentadienide , are generally prepared from the hexacarbonyl or tris(acetonitrile) tricarbonyl precursor and the respective ligand in refluxing alkanes or ethers. We reported on the first imidazolium Cp carbonyl complex, which was synthesized from ylide B and tungsten hexacarbonyl in tetrahydrofuran under irradiation with UV light …”

Section: Introductionmentioning

confidence: 99%

Group 6 Carbonyl Complexes of C-Ylidic Cp Ligands

2020

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The synthesis and the analytical features of group 6 carbonyl complexes of electron-poor mono(imidazolium)-and bis(imidazolium)-substituted Cp ylides are presented. With the neutral ylidic imidazolium Cp and the monocationic 1,3bis(imidazolium) Cp ligand all of the group 6 carbonyl complexes were prepared, while in the case of the 1,2-disubstituted Cp ylide only the chromium Cp complex was accessible. The donor properties of the ligands were elucidated experimentally by means of the CO stretching frequencies of their group 6 metal complexes and theoretically by DFT calculations. Every imidazolium substituent and the planar conjugated π system of the imidazolium moieties annelated to the Cp ring increase the average CO stretching frequencies by about 20 cm −1 . Overall, the donor properties of the C-ylidic Cp ligands are still stronger than those of the benzene ligand. Additionally, the protonation of the Cp ligands was investigated, and the basicity correlates qualitatively with the electron-donor character of the ylidic Cp ligands.

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Transition Metal Complexes of Cyclopentadienylides and Pentafulvenes

Cited by 9 publications

References 4 publications

Trifluoromethyl-Substituted Benzocyclobutenone and Benzocyclobutenedione: The Structure Anomaly of (Benzocyclobutenedione)tricarbonylchromium Complexes

Trifluoromethyl-Substituted Benzocyclobutenone and Benzocyclobutenedione: The Structure Anomaly of (Benzocyclobutenedione)tricarbonylchromium Complexes

An Ylidic Cp and its Scandium Complexes in Equilibrium

Group 6 Carbonyl Complexes of C-Ylidic Cp Ligands

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