Bis(pyrazol-1-yl)acetic Acid Bearing Ferrocenyl Substituents (original) (raw)
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Inorganic Chemistry, 2003
The molecular structure of the previously reported species "[Fe(bdtbpza)Cl]" has been revealed by X-ray structure determination to be a ferrous dimer [Fe(bdtbpza)Cl] 2 (2c) [bdtbpza) bis(3,5-di-tert-butylpyrazol-1-yl)acetate]. The syntheses of ferrous 2:1 complexes [Fe(bpza) 2 ] (3a) and [Fe(bdtbpza) 2 ] (3c) as well as ferric 1:1 complexes [NEt 4 ]-[Fe(bpza)Cl 3 ] (4a) and [NEt 4 ][Fe(bdmpza)Cl 3 ] (4b) [bpza) bis(pyrazol-1-yl)acetate, bdmpza) bis(3,5-dimethylpyrazol-1-yl)acetate] are reported. Complexes 3a, previously reported [Fe(bdmpza) 2 ] (3b), and 3c are high-spin. No spin crossover to the low-spin state was observed in the temperature range of 5−350 K. 4a and 4b are synthesized in one step and in high yield from [NEt 4 ] 2 [Cl 3 FeOFeCl 3 ]. 4a and 4b are iron(III) high-spin complexes. Crystallographic information: 2c (C 24 H 39 ClFeN 4 O 2 ‚CH 2 Cl 2 ‚CH 3 CN) is triclinic, P1 h, a) 12.171(16) Å, b) 12.851(14) Å, c) 13.390-(13) Å, R) 98.61(9)°,) 113.51(11)°, γ) 108.10(5)°, Z) 2; 3a (C 8 H 7 Fe 0.5 N 4 O 2) is monoclinic, P2 1 /n, a) 7.4784(19) Å, b) 7.604(3) Å, c) 16.196(4) Å,) 95.397(9)°, Z) 4; 3c (C 24 H 39 Fe 0.5 N 4 O 2) is monoclinic, P2 1 /n, a) 9.939(6) Å, b) 18.161(10) Å, c) 13.722(8) Å,) 97.67(7)°, Z) 4; 4b (C 20 H 35 Cl 3 FeN 5 O 2) is monoclinic, C2/c, a) 30.45(6) Å, b) 12.33(2) Å, c) 16.17(3) Å,) 118.47(5)°, Z) 8.
Synthesis and complexation properties of novel triazoyl-based ferrocenyl ligands
Journal of Organometallic Chemistry, 2010
Two new ligand derivatives of ferrocene, namely N-4-[3,5-di-(2-pyridyl)-1,2,4-triazoyl]ferrocene carbimine (L1) and N-4-[3,5-di-(2-pyridyl)-1,2,4-triazoyl]ferrocene carbamide (L2), were synthesised in good yields by reacting the known compound 3,5-di-pyridine-2-yl-[1,2,4]triazol-4-ylamine (1) with ferrocenecarbaldehyde and chlorocarbonyl ferrocene, respectively. The structures of L1 and L2 were determined by X-ray crystallography. The complexation of L1 and L2 with Cu I , Ag I , Zn II and Cd II was studied by NMR and UV-vis spectroscopies, as well as by electrochemistry, with titrations used to determine metal:ligand stoichiometries. The cyclic voltammograms of L1 and L2 and their respective complexes indicated reversible one-electron transfers corresponding to the Fc 0/+ redox couple (Fc = ferrocene), with formal electrode potentials shifting to more positive values upon metal complexation.
Inorganic Chemistry, 2006
The lithium salt (L)Li(THF) (L -) bis(3,5-di-tertbutylpyrazol-1-yl)-1-CH 2 NAr, Ar ) 2,6-i Pr 2 C 6 H 3 ) can be readily prepared from lithium bis(3,5-di-tertbutylpyrazol-1-yl)methide and the N-methyleneaniline H 2 CdNAr. This N,N,N′-heteroscorpionate lithium reagent can be transmetalated with Tl(OTf), FeCl 2 (THF) 1.5 , and CoCl 2 to yield the (L)Tl, (L)FeCl, and (L)CoCl complexes, respectively. Single crystal structural data for compounds (L)Li(THF), (L)Tl, (L)FeCl, and (L)CoCl reveal in each case the hapticity of the sterically demanding, monoanionic Lligand to be κ 3 -N 3 . Figure 2. Cyclic voltamograms of complexes 3 and 4 in 0.3 M TBAPF6 in THF using a scan rate of 250 mV/s and referenced to the FeCp2 0/+ couple (0.0 V). Scheme 2. Synthesis of Compounds 2-4 from 1
Journal of Organometallic Chemistry, 2001
A series of carbonylchromium, molybdenum and tungsten complexes containing ferrocenylpyrazole ligands, (M(CO) 5 L) (M = Cr, Mo or W; L represents ferrocenyl pyrazole), have been prepared by the photochemical reactions of ferrocenylpyrazole ligands with M(CO) 6 . Their electrochemical behaviors have also been investigated by cyclic voltammetry, indicating that chromium complexes exhibit two one-electron reversible or quasi-reversible couples, while molybdenum and tungsten complexes have one reversible couple corresponding to the ferrocenyl group and one irreversible oxidation process for the molybdenum or tungsten center. The crystal structures of 3-ferrocenylpyrazole pentacarbonyltungsten (3) and 3-methyl-5-ferrocenylpyrazole pentacarbonyltungsten (6) are determined by X-ray diffraction method, indicating that both 3(5)-ferrocenylpyrazole and 3(5)-methyl-5(3)-ferrocenylpyrazole act as a monodentate ligand, and the central metal of W is six-coordinate with a quasi-octahedral coordination geometry in both complexes. Complex 3 is linked into a one-dimensional chain in solid through intermolecular hydrogen bonds formed by metal carbonyl as hydrogen bond acceptors, while complex 6 forms a dimer by similar intermolecular hydrogen bond interactions. The N-H···O distances in complexes 3 and 6 are 2.932(11) and 2.900 A , , respectively. All new compounds have been characterized by elemental analyses, IR, 1 H-NMR. 13 C-NMR spectra of molybdenum and tungsten complexes have also been determined.
Inorganic Chemistry, 2006
The successful design and synthesis of the new bis(pyrazolyl)ethanamine ligand and its copper(I) triphenylphosphine complex is reported. The ligand coordinates to the copper(I) center in a fac tridentate fashion, through both the pyrazolyl rings and the nitrogen atom from the NH 2 group. In the solid state, the compound is organized in a 2D noncovalent network by N−H‚‚‚π and C−H‚‚‚π interactions and hydrogen bonds. The analogous ligand with a benzyl group substituted on the amine forms a complex with the same copper(I) center that has a similar 2D supramolecular structure and, in addition, is organized by the benzyl synthon into a 3D architecture.
Inorganic Chemistry, 2005
Cl 4 ] with bis(pyrazol-1-yl)methane (bpzm) and bis(pyrazol-1-yl)acetate (Hbpza) and with the lithium salts lithium [bis(3,5-dimethylpyrazol-1-yl)acetate] (Libdmpza) and lithium [bis(3,5-dimethylpyrazol-1-yl)methanesulfonate] (Libdmpzs) produce a series of new compounds containing either a κ 2 -N,N bidentate pyrazolyl ]. X-ray analyses of 1 and 3 show in both cases a distorted octahedral environment around the rhenium atom. The nature and the geometry of the products are strongly determined by the reaction solvent and by the heteroscorpionate ligand itself. When scorpionates bear methylated pyrazolyl rings mixed heterocomplexes Re(O)(bdmpza)(glycol) (11) and Re(O)(bdmpzs)(glycol) (12) are obtained (H 2 glycol ) ethylene glycol). Also 11 shows an octahedral geometry as assessed by X-ray study. Boschi, A.; Uccelli, L.; Tisato, F.; Refosco, F.; Cagnolini, A.; Duatti, A.; Prakash, S.; Bandoli, G.; Vittadini, A. J. Am. Chem. Soc. 2002, 124, 11468-11479. (7) Porchia, M.; Tisato, F.; Refosco, F.; Bolzati, C.; Cavazza-Ceccato, M.; Bandoli, G.; Dolmella A. Inorg. Chem. 2005, in press.
Dalton Transactions, 2009
The synthesis of ferrocene-based heteroditopic receptors in which the ferrocene moiety is attached to an imidazo [4,5-e]benzothiadiazole or imidazo[4,5-f ]quinoxaline is reported. These nitrogen-rich ferrocene derivatives show remarkable ion-sensing properties because of the presence of the redox active ferrocene unit and the polyazaheteroaromatic ring systems which act as a dual binding site for anions and metal cations. They display an anodic shift of the oxidation wave (DE 1/2 = 67-200 mV) upon complexation with metal cations and a strong cathodic shift (DE 1/2 = -82 to -100 mV) in the presence of Fand HP 2 O 7 3anions. For the Zn 2+ , Cd 2+ , Hg 2+ and Pb 2+ metal cations tested, the change in the absorption spectra is accompanied by a dramatic colour change which allows the potential for "naked eye" detection.
Inorganic Chemistry, 2001
The novel ferrocenyl ligand rac-1,6-diferrocenyl-N,N′-bis(2-hydroxypropyl)-2,5-diazahexane (1, H 2 L) was synthesized from ferrocenylcarboxaldehyde and ethylenediamine followed by the reduction of the Schiff base with LiAlH 4 and subsequent N-alkylation with 1,2-propyleneoxide. The dianion of H 2 L reacted with [ReO(PPh 3 ) 2 -Cl 3 ], and the product was treated with NH 4 PF 6 to afford the complex [ReO(L-N 2 O 2 )PPh 3 ]PF 6 (2). Both the ferrocenyl ligand and the complex were characterized in solution by NMR spectroscopy and in the solid state by singlecrystal X-ray diffraction studies. NMR investigations reveal two solvent-dependent isomers for the ferrocenyl ligand in solution of which the major form is the more ordered one. The cation of 2 displays a nonsymmetrically coordinated N 2 O 2 ligand.
Polyhedron, 2018
Treatment of Fe(g 5-C 5 H 4 CH 2 OH) 2 (1) with two equivalents of ClC(O)R (2) (a, R = 2-c C 4 H 3 O; b, R = 2-c C 4 H 3 S; c, R = 2-c C 4 H 3 Se; d, R = 3-c C 4 H 3 S) produced the corresponding ferrocenylmethyl carboxylates Fe(g 5-C 5 H 4 CH 2 OC(O)R) 2 (3a-d), while the reaction of FcCH 2 OLi (Fc = Fe(g 5-C 5 H 5)(g 5-C 5 H 4)) with 2,5-(ClC(O)) 2-c C 4 H 2 X (5) (a, X = O; b, X = S; c, X = Se) in a 2:1 molar ratio gave 2,5-(FcCH 2 OC(O)) 2-c C 4 H 2 X (6a-c). Compounds 3a-d and 6a-c were characterized by elemental analysis, NMR (1 H and 13 C{ 1 H}) and IR spectroscopy. The molecular structures of 3a,b,d in the solid state were determined by single crystal X-ray structure analysis. Compound 3a crystallizes in the monoclinic space group P2 1 /c, while 3b,d crystallize in the triclinic space group P-1 À. The ester groups and the heteroatoms are in an anti arrangement with respect to each other. Cyclic voltammetry measurements for 3a-d and 6a-c show reversible electrochemical processes (Fc/Fc +) between 165 and 176 mV for 3a-d, and 94 and 116 mV for 6a-cb, using [N n Bu 4 ][B(C 6 F 5) 4 ] as the supporting electrolyte. It was found that for 3a, a somewhat higher Fc/ Fc + redox potential (E 0 0) is observed when compared with the more electron-rich systems 3b,c,d. The molecular electronic structures of the title compounds were additionally investigated by DFT calculations, revealing different degrees of HOMO-LUMO energy gaps within the series, due to a lowering of the LUMO energy, depending on the nature of the heterocyclic ring.