Tertiary phosphine induced migratory carbonyl insertion in cyclopentadienyl complexes of iron(II)

Makunya, Ntaoleng M.; Meijboom, Reinout; Muller, Alfred; Roodt, Andreas

doi:10.1016/j.jorganchem.2005.06.020

Cited by 11 publications

(6 citation statements)

References 28 publications

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“…Yields of 2 in the reactions of 1 with dppe and 1 eq of N∩N are similar (20 vs. 18%, respectively), suggesting that the nature of the entering ligand is not a crucial factor. Such behavior, that is, the promotion of the CO insertion into Fe II –C bonds by phosphines and other ligands, has been reported in the literature …”

Section: Resultssupporting

confidence: 54%

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)

et al. 2020

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Bis-cyclometalated iron(II) complex [Fe(κC,Nphpy) 2 (CO) 2 ] (1) (phpyH = 2-phenylpyridine) has been prepared in good yield from [Fe(CO) 5 ] and [Hg(phpy) 2 ] in the presence of dibromine, which is unexpectedly a crucial component of the reaction mixture. It is needed for the generation of short-lived reactive intermediate [FeBr(CO) 5 ]Br, which is actually involved in the electrophilic substitution reaction with [Hg(phpy) 2 ]. When irradiated by visible light, compound 1 readily affords bis(2-(pyridine-2-yl)phenyl)methanone ( 2) and iron oxides through the insertion of CO in the Fe−C bond of the cyclometalated moiety. Structures of iron complex 1 and ketone 2 were confirmed by X-ray crystallography. Activation of [Fe(CO) 5 ] by Br 2 represents a new approach for generating an iron intermediate, which is active in transmetalation reactions. Cytotoxic activity of 1 was tested against three gastric cancer cell lines, KATO III, AGS, and NUGC3. The activity against KATO III and NUGC3 cells is moderate, while complex 1 displayed excellent cytotoxicity against AGS cells. The molecular mechanism investigation showed that the cytotoxic activity of 1 appears independent of caspase 3 and the TP53 tumor suppressor gene, suggesting an apoptotic-independent process.

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Section: Resultssupporting

confidence: 54%

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)

et al. 2020

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“…In general, electron donating ligands in a metal alkyl complex will facilitate the alkyl migration process (through weakening of the metal-C s-bond) whereas electron-withdrawing ligands will strengthen the metalalkyl bond making the process less feasible. 52 Generally, slow alkyl migration will increase the residence time of the alkyl intermediate thereby creating the possibility of reacting with either H 2 or [HCo(CO) 3 P], resulting in hydrogenation of the olefin to form alkanes. 53 Since the correlation between steric and electronic factors do not always display well defined text book correlations with several of the catalytic parameters presented here, it suggests that there may be deviation in the mechanism/catalytic cycle amongst this selection of ligands.…”

Section: Catalytic Studiesmentioning

confidence: 99%

Evaluation of ligand effects in the modified cobalt hydroformylation of 1-octene. Crystal structures of [Co(L)(CO)3]2 (L = PA–C5, PCy3 and PCyp3)

Bungu

Otto

2011

Dalton Trans.

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A series of phosphine ligands with different electronic and steric properties were evaluated at fully modified conditions in cobalt catalysed hydroformylation of 1-octene. The steric demand of the ligands was based on the Tolman cone angle model covering a range of 132-175°. The electron donating ability was evaluated through the first order Se-P coupling constants as determined from the corresponding phosphine selenides covering a range of 672-752 Hz. Crystal structures of three phosphine modified cobalt dimers, [Co(CO)(3)(L)](2) (L = PA-C(5), PCy(3) and PCyp(3) with PA-C(5) = 1,3,5,7-tetramethyl-8-pentyl-2,4,6-trioxa-8-phosphatricyclo[3.3.1.1(3,7)]decane), are reported. The Phoban and Lim ligands (Phoban = mixture of 9-phosphabicyclo[3.3.1 and 4.2.1]nonane, Lim = 4,8-dimethyl-2-phosphabicyclo[3.3.1]nonane) resulted in systems about twice as active as most of the other ligands investigated, these ligands have a high Lewis basicity with (1)J(Se-P) values from 684-687 Hz. The linearity of the alcohol product in general decreased for the less electron donating ligands while no clear relationship was evident as a function of steric size. The parallel competing hydrogenation of 1-octene to octane varied from 9-15% for a cone angle range of 132-172°, but a sharp increase of up to 40% was observed for PA-C(5), PCy(3) and PCyp(3), all with cone angles > 169°. The catalytic behaviour provides evidence that is contrary to the dissociative substitution of CO by an alkene as the rate limiting step in all cases. For large symmetrical ligands, such as PA-C(5), PCy(3) and PCyp(3) the rate limiting step may move within the catalytic cycle and may now be situated at the carbonylation step where the chemoselectivity is also determined. The lack of clear correlation between the steric and electronic effect of the ligands and all catalytic parameters may serve as additional proof that the same system, especially in terms of the rate determining step, is not operative in all cases. The Phoban and Lim systems are superior with the highest reactivity and lowest alkene loss through hydrogenation. The unsymmetrical nature of the Phoban and Lim ligands may provide flexibility to adopt geometries inducing both high and low steric crowding, which may be a reason for its beneficial catalytic properties.

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“…The C-O bond lengths are between 1.13-1.16 Å (see Table S1), and they decrease in the sequence p-H > p-NH 2 > p-Br, which indicates that an increased contribution of resonance structure due to an increase in the character π-acceptor of the ligand and/or the effect of the electronegativity of p-substituent in benzonitrile molecules causes that the Fe back-bonding into the CO π* orbital is less important and the distance increases [24]. An increase of strong π-acceptor character in benzonitrile molecules, compete with CO molecule for the electron back-donation and the CO stretch frequencies remain high, as also observed by the FTIR stretching frequencies as well [25]. The distances between Fe and the centroids of the π-bonded cyclopentadienyl moiety to Fe centre are: 1.7158 17 Table S1 contains selected bond lengths and angles for all of the compounds.…”

Section: Uv-vis Spectroscopymentioning

confidence: 78%

A New Family of Iron(II)-Cyclopentadienyl Compounds Shows Strong Activity against Colorectal and Triple Negative Breast Cancer Cells

et al. 2020

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A family of compounds with the general formula [Fe(η5-C5H5)(CO)(PPh3)(NCR)]+ has been synthesized (NCR = benzonitrile (1); 4-hydroxybenzonitrile (2); 4-hydroxymethylbenzonitrile (3); 4-aminobenzonitrile (4); 4-bromobenzonitrile (5); and, 4-chlorocinnamonitrile (6)). All of the compounds were obtained in good yields and were completely characterized by standard spectroscopic and analytical techniques. Compounds 1, 4, and 5 crystallize in the monoclinc P21/c space group and packing is determined by short contacts between the phosphane phenyl rings and cyclopentadienyl (compounds 1 and 4) or π-π lateral interactions between the benzonitrile molecules (complex 5). DFT and TD-DFT calculations were performed to help in the interpretation of the experimental UV-Vis. data and assign the electronic transitions. Cytotoxicity studies in MDA-MB-231 breast and SW480 colorectal cancer-derived cell lines showed IC50 values at a low micromolar range for all of the compounds in both cell lines. The determination of the selectivity index for colorectal cells (SW480 vs. NCM460, a normal colon-derived cell line) indicates that the compounds have some inherent selectivity. Further studies on the SW480 cell line demonstrated that the compounds induce cell death by apoptosis, inhibit proliferation by inhibiting the formation of colonies, and affect the actin-cytoskeleton of the cells. These results are not observed for the hydroxylated compounds 2 and 3, where an alternative mode of action might be present. Overall, the results indicate that the substituent at the nitrile-based ligand is associated to the biological activity of the compounds.

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Tertiary phosphine induced migratory carbonyl insertion in cyclopentadienyl complexes of iron(II)

Cited by 11 publications

References 28 publications

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)

Evaluation of ligand effects in the modified cobalt hydroformylation of 1-octene. Crystal structures of [Co(L)(CO)3]2 (L = PA–C5, PCy3 and PCyp3)

A New Family of Iron(II)-Cyclopentadienyl Compounds Shows Strong Activity against Colorectal and Triple Negative Breast Cancer Cells

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Tertiary phosphine induced migratory carbonyl insertion in cyclopentadienyl complexes of iron(II)

Cited by 11 publications

References 28 publications

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)5: Synthesis, Properties, and Cytotoxicity of Bis(2-C6H4-2′-py-κC,N)dicarbonyliron(II)

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)5: Synthesis, Properties, and Cytotoxicity of Bis(2-C6H4-2′-py-κC,N)dicarbonyliron(II)

Evaluation of ligand effects in the modified cobalt hydroformylation of 1-octene. Crystal structures of [Co(L)(CO)3]2 (L = PA–C5, PCy3 and PCyp3)

A New Family of Iron(II)-Cyclopentadienyl Compounds Shows Strong Activity against Colorectal and Triple Negative Breast Cancer Cells

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Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)

Dibromine Promoted Transmetalation of an Organomercurial by Fe(CO)₅: Synthesis, Properties, and Cytotoxicity of Bis(2-C₆H₄-2′-py-κC,N)dicarbonyliron(II)