Complexes CpFe Research Articles

Half‐Sandwich Iron Chalcogenopropargylcarbonato Complexes as CO‐Releasing Molecules

ABSTRACTInteraction of iron chalcogenides (μ‐Ex)[CpFe(CO)2]2 (E = S; x = 2–4, E = Se, x = 1) with propargyl chloroformate (ClCO2CH2C≡CH) in diethyl ether yielded iron(II) chalcogenopropargylcarbonato complexes CpFe(CO)2ECO2CH2C≡CH (E = S (1), Se (2)). These complexes have been characterized by elemental analysis, UV–Vis, IR, and 1H‐ and 13C{1H}‐NMR spectroscopy and single‐crystal x‐ray diffraction techniques. Further, the suitability of complexes 1 and 2 as CO‐releasing molecules (CORMs) for the administration of carbon monoxide has been studied. CO gas is released upon irradiation of THF solution of these complexes in the presence of hemoglobin.

Synthesis, anticancer activity, and molecular docking of half-sandwich iron(II) cyclopentadienyl complexes with maleimide and phosphine or phosphite ligands

In these studies, we designed and investigated the potential anticancer activity of five iron(II) cyclopentadienyl complexes bearing different phosphine and phosphite ligands. All complexes were characterized with spectroscopic analysis viz. NMR, FT–IR, ESI–MS, UV–Vis, fluorescence, XRD (for four complexes) and elemental analyses. For biological studies, we used three types of cells—normal peripheral blood mononuclear (PBM) cells, leukemic HL-60 cells and non-small-cell lung cancer A549 cells. We evaluated cell viability and DNA damage after cell incubation with these complexes. We observed that all iron(II) complexes were more cytotoxic for HL-60 cells than for A549 cells. The complex CpFe(CO)(P(OPh)3)(η1-N-maleimidato) 3b was the most cytotoxic with IC50 = 9.09 µM in HL-60 cells, IC50 = 19.16 µM in A549 and IC50 = 5.80 µM in PBM cells. The complex CpFe(CO)(P(Fu)3)(η1-N-maleimidato) 2b was cytotoxic only for both cancer cell lines, with IC50 = 10.03 µM in HL-60 cells and IC50 = 73.54 µM in A549 cells. We also found the genotoxic potential of the complex 2b in both types of cancer cells. However, the complex CpFe(CO)2(η1-N-maleimidato) 1 which we studied previously, was much more genotoxic than complex 2b, especially for A549 cells. The plasmid relaxation assay showed that iron(II) complexes do not induce strand breaks in fully paired ds-DNA. The DNA titration experiment showed no intercalation of complex 2b into DNA. Molecular docking revealed however that complexes CpFe(CO)(PPh3) (η1-N-maleimidato) 2a, 2b, 3b and CpFe(CO)(P(OiPr)3)(η1-N-maleimidato) 3c have the greatest potential to bind to mismatched DNA. Our studies demonstrated that the iron(II) complex 1 and 2b are the most interesting compounds in terms of selective cytotoxic action against cancer cells. However, the cellular mechanism of their anticancer activity requires further research.

Germylene-Fe complexes caused by heterometallic coupling and investigation into the 3d-4p bonding

The interpretation of heterometallic bonding nature is a basic work of inorganic chemistry. By means of intermetallic substitution of germylene anions with iron halide complexes CpFe(CO)2I and β-diketiminato FeII chloride, the ferrogermylene complexes 3a, 3b and 4a were synthesized and structurally characterized. The structural and IR characterizations show the presence of the Ge←Fe π backbonding in molecules 3a, 3b and 4a. The computational works on frontier molecular orbitals and their comparison of energy states confirmed that σ donation and π backbonding are both weak in these molecules, despite three complexes have longer Ge-Fe bonds, whose strength decreases slightly with the degressive electron density around Fe environment in a sequence from 3a, 3b to 4a.

Cyclopentadienyl iron dicarbonyl styrene chalcogenosulfonates: synthesis and structure of CpFe(CO)2SeSO2CH=CHPh

In this contribution, we report the preparation of iron thiosulfonato complex CpFe(CO)2SSO2CH=CHPh (1) and its selenosulfonato analogue CpFe(CO)2SeSO2CH=CHPh (2) featuring styrene moiety. 1 and 2 are obtained by electrophilic attack of (μ-Ex)[CpFe(CO)2]2 (E = S; x = 2–4, E = Se; x = 1) on the sulfur atom of styrene sulfonyl chloride ClSO2CH=CHPh. The new compounds, 1 and 2 have been characterized by elemental analyses, IR, 1H-, 13C{1H}-NMR, UV–Vis spectroscopy and the structure of 2 is determined by X-ray crystallography. In this contribution, we report the preparation of iron thiosulfonato complex CpFe(CO)2SSO2CH=CHPh (1) and its selenosulfonato analogue CpFe(CO)2SeSO2CH=CHPh (2) featuring styrene moiety. 1 and 2 are obtained by electrophilic attack of (μ-Ex)[CpFe(CO)2]2 (E = S; x = 2–4, E = Se; x = 1) on the sulfur atom of styrene sulfonyl chloride ClSO2CH=CHPh. The new compounds, 1 and 2 have been characterized by elemental analyses, IR, 1H-, 13C{1H}-NMR, UV–Vis spectroscopy and the structure of 2 is determined by X-ray crystallography..

Halfsandwich iron S-alkyl dithiocarbonato complexes: Synthesis, characterization and reactivity

Three iron S-alkyl dithiocarbonato complexes CpFe(CO)2SC(O)SR (R = C2H5 (1), n-C3H7 (2) iso-C3H7 (3)) are synthesized via the reaction of the iron sulfides, (μ-Sx)[CpFe(CO)2]2 (x = 1–5) with S-alkyl chlorothioformates RSC(O)Cl. The CO-substitution reactions of 1 with triphenylphosphine, triphenylarsine or triphenylantimony (EPh3) gave the monosubstituted complexes CpFe(CO)(EPh3)SC(O)SEt (E = P (4a), As (4b), Sb (4c)) in high yields. The newly synthesized complexes have been characterized by IR, 1H, 13C{1H} NMR spectroscopy and elemental analysis. The solid state structure of CpFe(CO)2SC(O)SEt (1) is determined by X-ray crystal structure analysis.

Half-sandwich iron complexes bearing vinyl-selenocarboxylato ligands

Vinyl selenocarboxylato iron complexes of the formula CpFe(CO)2SeCOCH=C(R1)(R2) {R1 = H, R2 = Me, R1 = R2 = Me, R1 = H, R2 = CH=CHMe} are synthesized by the reaction of (µ-Se)[CpFe(CO)2]2 with the corresponding vinyl acid chlorides ClCOCH=C(R1)(R2). Photolytic substitutions of CpFe(CO)2SeCOCH=CMe2 with EPh3 gave the monosubstituted complexes CpFe(CO)(EPh3)SeCOCH=CMe2 (E = P, As, Sb) in good yields. The new complexes have been characterized by UV-Vis, IR, 1H-NMR, 13C{1H}-NMR, 77Se{1H}-NMR, 31P{1H}-NMR spectroscopy and elemental analysis. The solid state structures of CpFe(CO)2SeCOCH=CMe2 and CpFe(CO)(AsPh3)SeCOCH=CMe2 were determined by X-ray crystallography. The cyclic voltammetric measurements of CpFe(CO)2SeCOCH=CMe2 were recorded. Vinyl selenocarboxylato iron complexes of the formula CpFe(CO)2SeCOCH=C(R1)(R2) {R1 = H, R2 = Me, R1 = R2 = Me, R1 = H, R2 = CH=CHMe} are synthesized by the reaction of (µ-Se)[CpFe(CO)2]2 with the corresponding vinyl acid chlorides ClCOCH=C(R1)(R2). Photolytic substitutions of CpFe(CO)2SeCOCH=CMe2 with EPh3 gave the monosubstituted complexes CpFe(CO)(EPh3)SeCOCH=CMe2 (E = P, As, Sb) in good yields. The new complexes have been characterized by UV-Vis, IR, 1H-NMR, 13C{1H}-NMR, 77Se{1H}-NMR, 31P{1H}-NMR spectroscopy and elemental analysis. The solid-state structures of CpFe(CO)2SeCOCH=CMe2 and CpFe(CO)(AsPh3)SeCOCH=CMe2 were determined by X-ray crystallography and the cyclic voltammetric measurements of CpFe(CO)2SeCOCH=CMe2 were recorded.

Vinylic-thiocarboxylate complexes of iron: synthesis, characterization and reactions

Half-sandwich iron thiocarboxylate complexes of the general formula CpFe(CO)2SCOCH=C(R′)(R″){R′ = H, R″ = Me, R′ = R″ = Me, R′ = H, R″ = CH=CHMe}) are obtained from the reaction of (µ-Sx)[CpFe(CO)2]2 (x = 1–5) with the vinyl acid chlorides ClCOCH=C(R′)(R″). The substitution reaction of CpFe(CO)2SCOCH=C(R)Me with EPh3 produced the monosubstituted complexes CpFe(CO)(EPh3)SCOCH=C(R)Me (R = Me, E = P, R = H, E = As, Sb). All the new complexes have been characterized by UV-Vis, IR, 1H-NMR, 13C{1H}-NMR, 31P{1H}-NMR spectroscopy and elemental analysis. The solid state structures and the cyclic voltammetric measurements of CpFe(CO)2SCOCH=CMe2 and CpFe(CO)(PPh3)SCOCH=CMe2 were determined. Half-sandwich iron thiocarboxylate complexes of the general formula CpFe(CO)2SCOCH=C(R′)(R″){R′ = H, R″ = Me, R′ = R″ = Me, R′ = H, R″ = CH=CHMe}) are obtained from the reaction of (µ-Sx)[CpFe(CO)2]2 (x = 1–5) with the vinyl acid chlorides ClCOCH=C(R′)(R″). The substitution reaction of CpFe(CO)2SCOCH=C(R)Me with EPh3 produced the monosubstituted complexes CpFe(CO)(EPh3)SCOCH=C(R)Me (R = Me, E = P, R = H, E = As, Sb). All the new complexes have been characterized by UV-Vis, IR, 1H-NMR, 13C{1H}-NMR, 31P{1H}-NMR spectroscopy and elemental analysis. The solid state structures and the cyclic voltammetric measurements of CpFe(CO)2SCOCH=CMe2 and CpFe(CO)(PPh3)SCOCH=CMe2 were determined.

Towards the synthesis of piano-stool iron complexes mediated by S-alkyl selenothiocarbonato ligands and their substitution reactions

The S-alkyl selenothiocarbonato iron complexes of the general formula CpFe(CO)2SeC(O)SR (R = Et, n-Pr, i-Pr) are made by the reactions of (µ-Se)[FeCp(CO)2]2 and S-alkyl chlorothioformates RSC(O)Cl. The CO-substitution reactions of CpFe(CO)2SeC(O)SEt with triphenylphosphine, triphenylarsine, or triphenylantimony (EPh3) gave the monosubstituted complexes CpFe(CO)(EPh3)SeC(O)SEt (E = P, As, Sb) in high yields. All the S-alkyl selenothiocarbonato iron complexes have been characterized by IR, MS, 1H, 77Se, 31P, 13C NMR spectroscopy, and elemental analysis. The solid-state structures of CpFe(CO)2SeC(O)SiPr and CpFe(CO)(PPh3)SeC(O)SEt, were determined by X-ray crystal structure analysis. The cyclic voltammetry of the same two complexes was also investigated.

Synthesis, characterization and electrocatalytic H2 production of phosphine-substituted CpFe complexes

Reaction of Ph2P(Se)CSNHPh with Cp2Fe2(CO)4 in refluxing toluene affords complexes CpFe(CO)(k2P,S-Ph2PC(S)NPh) (1) and CpFe(CO)2(kP-P(Se)Ph2) (2). Further, reactions of 2 with 1 equiv of PPh2R in the presence of Me3NO generate complexes CpFe(CO)(kSe-SeP(Se)Ph2)(L) (3, L = PPh3; 4, L = PPh2Py). Unlike 2, reactions of CpFe(CO)2(kP-P(S)Ph2) with PPh2R under the same conditions give the corresponding phosphine-substituted complexes CpFe(CO)(kP-P(S)Ph2)(L) (5, L = PPh3; 6, L = PPh2Py). All the new compounds have been characterized by elemental analyses, IR, 1H NMR, 13C NMR and 31P NMR spectroscopy and structurally determined by X-ray crystallography. Electrochemical studies indicate that using HOAc or TFA as a proton source complexes 1–6 can catalyze H2 evolution.

Substitution reactions of mono-, di- and tri-thiocarbonato complexes of iron

The photolytic reactions of iron thiocarbonato complexes CpFe(CO)2SC(Y)Y′R [Y=Y′=O; R=2-C6H4Cl (1), 4-C6H4Cl (2); Y=S, Y′=O; R=C6H4F (3), Y=Y′=S; R=Ph (4)] with EPh3 (E=P, As, Sb) are performed. Monosubstituted complexes of the general formula CpFe(CO)(EPh3)SC(Y)Y′R [Y=Y′=O; R=2-C6H4Cl (5), 4-C6H4Cl (6); Y=S, Y′=O; R=C6H4F (7), Y=Y′=S; R=Ph (8); E=P (a), As (b), Sb (c)] have been isolated and characterized by spectroscopic analysis (UV–Vis, IR, 1H, 31P NMR) and elemental analysis. The molecular structures of CpFe(CO)(PPh3)SCO2-2-C6H4Cl (5a) and its dicarbonyl parent CpFe(CO)2SCO2-2-C6H4Cl (1) have been determined by single crystal X-ray crystallographic studies.

Cyclopentadienyl iron dicarbonyl (CpFe(CO)2) derivatives as apoptosis-inducing agents

CpFe(CO)2 complexes kill cancer cells while leaving normal cells unharmed.

Thio- and selenosulfonato complexes of iron bearing aromatic and heterocyclic groups

Various new thio- and selenosulfonato complexes of iron were synthesized by straight forward route. Treatment of the iron chalcogenides, (μ-Ex)[CpFe(CO)2]2 (E=S; x=2–4, E=Se; x=1) with sulfonyl chlorides produced the corresponding thio- or selenosulfonato complexes CpFe(CO)2ESO2Ar [Ar=2-C4H3S (1), 5-C4H2SCl (2), 1,3-C6H4SO2Cl (3), 1,3-C6H4CO2H (4); E=S (a), Se (b)]. The dimers [CpFe(CO)2ESO2]2(1,3-C6H4) (5) are obtained from the iron chalcogenides with 1,3-C6H4(SO2Cl)2 in a 2:1 molar ratio. All of these new complexes have been characterized by IR, 1H, 13C NMR spectroscopy, UV–Vis and elemental analysis. The X-ray structure of CpFe(CO)2ESO2-1,3-C6H4SO2Cl (3a) is determined.

Mono- and bi-iron chalcogenocarboxylate complexes

A series of thiocarboxylato and selenocarboxylato monomeric CpFe(CO)2ECORCOCl and dimeric [CpFe(CO)2ECO]2R iron complexes have been synthesized and characterized. The interaction of (μ-Ex)[CpFe(CO)2]2 (E = S; x = 2–4. E = Se; x = 1) with di-acid chlorides (ClCORCOCl) in a 1:1 molar ratio gave the monomeric complexes CpFe(CO)2ECORCOCl for R = 1,3-C6H4, 2,6-C5H3N, 1,2-C6H4. However, the dimeric complexes [CpFe(CO)2ECO]2R were obtained from the same reactants in a 2:1 metal-to-ligand molar ratio in which R is 1,3-C6H4, 2,6-C5H3N or C2H4. The monomer versus dimer production mainly depends on the electronic and steric factors of the R-moiety. The new monomeric and dimeric thio- and selenocarboxylato iron complexes have been characterized by spectroscopic techniques (1H- and 13C-NMR, IR) and by elemental analysis. The structures of [CpFe(CO)2SCO]2(1,3-C6H4) and its seleno analogue [CpFe(CO)2SeCO]2(1,3-C6H4) were determined by X-ray structure determination.

Heterocyclic thiocarboxylato complexes of iron: synthesis, characterization, electrochemistry, and reactions

Heterocyclic-thiocarboxylato complexes of iron, CpFe(CO)2SCO-het (het = 2-C4H3O, 2-C4H3S, CH2-2-C4H3S), have been synthesized via the reaction of iron sulfides, (μ-S x )[CpFe(CO)2]2 (x = 3, 4), with heterocyclic acid chlorides het-COCl. Photolytic substitutions of these complexes CpFe(CO)2SCO-het with triphenylphosphine, triethylphosphite, triphenylarsine, and triphenylantimony [ER3 (E = P, R = Ph, OC2H5; E = As, Sb, R = Ph)] exclusively gave the monosubstituted complexes CpFe(CO)(ER3)SCO-het in good yields. The new complexes have been characterized by elemental analysis, UV-Vis, IR, 1H, and 31P NMR spectroscopies and by cyclic voltammetry for a representative family (1, 4a–d). The solid state structures of CpFe(CO)2SCO(2-C4H3S) (2), CpFe(CO)(PPh3)SCO(2-C4H3S) (5a), CpFe(CO)(AsPh3)SCO(2-C4H3S) (5b), and CpFe(CO)(SbPh3)SCO(2-C4H3S) (5c) were determined by X-ray crystal structure analysis.

Synthesis and Reactivity of Mono‐, Di‐, and, Triiron Selenocarboxylate Complexes

AbstractTreatment of the iron selenide (μ‐Se)[CpFe(CO)2]2 with one equivalent of 1, 3, 5‐C6H3(COCl)3 gave the organoiron selenocarboxylate complex CpFe(CO)2SeCO‐3, 5‐C6H3(COCl)2 (1), which contains two free acid chloride groups. Complex 1 reacted with amines, thiols, and phenols to produce the corresponding amides CpFe(CO)2SeCO‐3, 5‐C6H3(CONR2)2 (2), thioesters CpFe(CO)2SeCO‐3, 5‐C6H3(COSR)2(3), and aromatic esters CpFe(CO)2SeCO‐3, 5‐C6H3(CO2Ar)2 (4), respectively. Complex 1 was converted into the diacid CpFe(CO)2SeCO‐3, 5‐C6H3(COOH)2 (5) or the diamide CpFe(CO)2SeCO‐3, 5‐C6H3(CONH2)2 (6) complexes by reactions with NaOH or NaNH2, respectively. The bis(seleno)‐1, 3‐(CpFe(CO)2SeCO)2‐5‐C6H3(COCl) (7) and tris(seleno)‐carboxylate 1, 3, 5‐(CpFe(CO)2SeCO)3C6H3 (8) complexes were also prepared by controlled reaction of 1, 3, 5‐C6H3(COCl)3 with the iron selenide (μ‐Se)[CpFe(CO)2]2. Complexes 1–8 were characterized by spectroscopic techniques (IR, 1H‐NMR) and by elemental analysis as well. The X‐ray structures of CpFe(CO)2SeCO‐3, 5‐C6H3(COCl)2 (1) and CpFe(CO)2SeCO‐3, 5‐C6H3(COSCH2Ph)2 (3b) were determined.

Metal-metal bond cleavage in [Cp(CO)2Fe-Fe(CO)2Cp] under the action of organotellurium(IV)tribromides

The oxidation of [CpFe(CO)2]2 by RTeBr3 allowed the corresponding organotellurodibromide complexes CpFe(CO)2TeBr2R (R=Ph, cyclo-(C8H12)(OMe). Their structural features (as determined by single-crystal X-ray diffraction analysis) are discussed.

Transition metal compounds containing alkynylsilyl groups − complexes with a metal-silicon bond

Two transition metal complexes containing alkynylsilyl groups and a metal−silicon bond (CpFe(CO)2SiMe2CCPh (1), Co(CO)4SiMe2CCPh (2)) have been synthesized by nucleophilic substitution (salt elimination) using both strongly and weakly nucleophilic metallates. No disturbing interactions of the metallate with the CC bond were observed. The synthesis of a third complex ((Ph3P)2RhClHSiMe2CCPh (3)) by oxidative addition was hampered by transition metal catalyzed reactions of the Si−H with the CC triple bond. The reactivity of 1 toward complexation and hydrosilylation of the CC triple bond was studied, leading to the trinuclear dicobaltatetrahedrane compound 1 ∗ Co2(CO)6 (4) and the vinylsilyl complex CpFe(CO)2SiMe2CH=CPh(SiEt3) (5), respectively. The complexes were characterized by NMR (1–5), IR (1–5), and UV/VIS spectroscopy (1, 3, 4) as well as X-ray crystallography (1–4).

(Acetonitrile-κN)[2-(diphenylphosphanyl)ethanamine-κ2N,P][(1,2,3,4,5-η)-1,2,3,4,5-pentamethylcyclopentadienyl]iron(II) hexafluoridophosphate tetrahydrofuran monosolvate

In the title cationic Cp*Fe(II) complex, [Fe(C10H15)(CH3CN)(C14H16NP)]PF6·C4H8O, the metal ion is coordinated by the η 5-Cp* ring as well as the P and N atoms of the chelating 2-(diphenyl­phosphino)ethyl­amine ligand and an additional acetonitrile mol­ecule in a piano-chair conformation. The PF6 − anion is disordered over two sets of sites with occupancies of 0.779 (7) and 0.221 (7).

Trans-selective hydrogermylation of alkynes promoted by methyliron and bis(germyl)hydridoiron complexes as a catalyst precursor

Catalytic trans-selective hydrogermylation of terminal and internal alkynes was attained by a methyliron complex, CpFe(CO)(2)(Me), and a bis(germyl)hydridoiron(IV) complex as a catalyst precursor. The structures of (Z)-triphenyl-(2-phenylethenyl)germane and the bis(germyl)hydridoiron(IV) complexes CpFe(CO)(H)(GeR(3))(2) (R = Et, Ph) were confirmed by single crystal X-ray diffraction studies.

ChemInform Abstract: Silicon-Silicon Interaction in Bis(silylene)iron, Disilanyliron, and Bis(silyl)iron Complexes

Abstract 29Si NMR coupling constants in a disilanyliron complex CpFe(CO)2SiMe2SiMe(OtBu)2 (1: CP = η5C5H5), a bis(silylene)iron complex Cp(OC)Fe{SiMe2 ⋯ O(tBu) ⋯ SiMeOtBu)} (2), and a cis-bis(silyl)iron complex (OC)4Fe{SiMe2CH2CH2SiMePh} (3) were measured by the INEPT-INADE-QUATE technique. The coupling constant for 2 (28.6 Hz) is much smaller than that for 1 (128 Hz) with a direct Si-Si bond, but larger than that for 3 (2.7 Hz) where there is no direct Si-Si bond. Model calculations using the extended Huckel method indicate that there is no direct bond between the two silicon atoms in the bis(silylene)iron complex Cp(OC)Fe{SiH2 ⋯ O(H) ⋯ SiH2}. This means that the coupling in 2 can be described as the sum of the two geminal couplings, 2J(SiFeSi) and 2J(SiOSi).