Chlorobis(2,2,2-trichloroethoxy)-and dichloro(2,2,2-trichloroethoxy)-iron(III): Synthesis,characterization, and coordination chemistry

Chlorobis(2,2,2-trichloroethoxy)- and dichloro(2,2,2-trichloroethoxy)iron(III) have been synthesized. They react with various oxygen and nitrogen donor ligands to yield adducts formulated as FeCl(OCH₂CCl₃)₂ · 2 L or FeCl₂(OCH₂CCl₃) · 2 L (L = ligand). The depressed magnetic moments of these compounds show the presence of strong antiferromagnetic interactions between iron atoms. The infrared and ¹H nmr spectra establish the presence of bridging and terminal alkoxy groups and ligands (L) are cis to each other. The electronic spectra of these complexes indicate that each iron atom is approximately octahedrally coordinated. Mass spectral data are in favour of dimeric structure for the title compounds.     

Preparation,Characterization, and Reactions of Dinuclear Tris(2,2,2-trichloroethoxy) Iron(III), Fe(OCH2CCl3)3

The preparation, electrical conductivity, magnetic moments, infrared, reflectance, and ⁵⁷Fe Mössbauer spectra of tris(2,2,2-trichloroethoxy) iron(III) and its adducts with some oxygen and nitrogen donor ligands are reported. Cryoscopic data of the parent compound and its complex with ethylacetate suggest these compounds to be dimeric in nitrobenzene and benzene respectively. All the compounds are covalent with Fe^III having distorted octahedral arrangement which is achieved through alkoxy bridging. The magnetic moments are lesser than those required for the spin only value indicating antiferromagnetic interactions in Fe^III atoms. The Mössbauer spectra are explained in terms of two Fe^III high spin sites corresponding to trans- and cis-positions in the structure.     

Synthesis,characterization and reactions of 2,2,2-trichloroethoxy derivatives of chromium(III)

Tris(2,2,2-trichloroethoxy)chromium(III) tetrahydrofuran solvate, Cr(OCH₂CCl₃)₃ ·THF; Chlorobis(2,2,2-trichloroethoxy)chromium(III)tetrahydrofuran solvate, CrCl(OCH₂CCl₃)₂ ·THF and dichloro(2,2,2-trichloroethoxy) chromium(III) tetrahydrofuran solvate, CrCl₂(OCH₂CCl₃) ·THF have been prepared. These compounds react with various oxygen and nitrogen donor ligands to form adducts of 1:2 composition. 2,2,2-trichloroethoxy bridged structures have been proposed on the basis of their infrared and¹H nmr spectra. The diffuse reflectance spectral results are consistent with an octahedral geometry for chromium(III) whereas their low magnetic moment values suggest polymeric structures exhibiting antiferromagnetic coupling between chromium(III) atoms. The mass spectral data of Cr(OCH₂CCl₃)₃ ·THF and CrCl(OCH₂CCl₃)₂ ·THF support the dimeric structures for these complexes.

---

Synthese, Charakterisierung und Reaktionen von 2,2,2-Trichlorethoxyderivaten von Chrom(III)

Zusammenfassung Es wurde Tris(2,2,2-trichlorethoxy)chrom(III)-tetrahydrofuransolvat, Cr(OCH₂CCl₃)₃ ·THF, Chlorbis(2,2,2-trichlorethoxy)chrom(III)tetrahydrofuransolvat, CrCl(OCH₂CCl₃)₂ ·THF, und Dichlor(2,2,2-trichlorethoxy)chrom(III)tetrahydrofuransolvat, CrCl₂(OCH₂CCl₃ ·THF, hergestellt. Diese Verbindungen reagieren mit verschiedenen Sauerstoff- und Stickstoffdonorliganden unter Bildung von Addukten mit der Zusammensetzung 1:2. Basierend auf IR- und¹H-NMR-Daten wurden 2,2,2-trichlorethoxyüberbrückte Strukturen vorgeschlagen. Die Resultate aus Diffuse-Reflectance-Messungen sind mit einer oktaedrischen Geometrie um Cr(III) in Übereinstimmung, während die niedrigen Werte für die magnetischen Momente polymere Strukturen mit antiferromagnetischer Kopplung zwischen den Chrom(III)-Atomen nahelegen. Die massenspektroskopischen Daten für Cr(OCH₂CCl₃)₃ ·THF und CrCl(OCH₂CCl₃)₂ ·THF sprechen für eine dimere Struktur dieser Komplexe.

     

Amidomethylation of Tris(2,2,2-trifluoroethyl) Phosphite

Russian Journal of General Chemistry -     

Tris(difluoro and trifluorobutane-2,4-dionato) gallium(III) and indium(III) complexes

Eight tris(β-diketonate)gallium(III) and seven tris(β-diketonate)-indium(III) complexes M(RCOCH-COR′)₃, with R′being difluoromethyl and trifluoromethyl substituents and R′ being methyl, phenyl, aryl, 2′-naphthyl and 2′-thienyl substituents have been studied by nuclear magnetic resonance spectroscopy. The complexes are all nonrigid (fluxional) and their ¹⁹F NMR spectra show four resonances in the nonexchanging regions due to cis and trans isomers. A variable low temperature study of these complexes was done for the gallium chelates and activation parameters are calculated. The indium complexes all have nonexchanging regions below ?100°C. The ¹³C NMR data on the complexes are also reported.     

Spin transition in iron(III) and iron(II) complexes

The main stages of the studies on the spin transitions in iron(III) and iron(II) complexes are considered. The types of the spin transitions and the factors responsible for the latter are reported. The problems arising during experiments in this field are discussed.     

Gaseous iron(II) and iron(III) complexes with BINOLate ligands

Electrospray ionization (ESI) of dilute solutions of 1,1'-bi-2-naphthol (BINOL) and iron(II) or iron(III) sulfate in methanol/water allows the generation of monocationic complexes of iron and deprotonated BINOL ligands with additional methanol molecules in the coordination sphere, and the types of complexes formed can be controlled by the valence of the iron precursors used in ESI. Thus, iron(II) sulfate leads to [(BINOLate)Fe(CH3OH)n]+ complexes (n=0-3), whereas usage of iron(III) sulfate allows the generation of [(BINOLdiate)-Fe(CH3OH)n]+ cations (n=0-2); here, BINOLate and BINOLdiate stand for singly and doubly deprotonated BINOL, respectively. Upon collision-induced dissociation, the mass-selected ions with n>0 first lose the methanol ligands and then undergo characteristic fragmentations. Bare [(BINOLdiate)Fe]+, a formal iron(III) species, undergoes decarbonylation, which is known as a typical fragmentation of ionized phenols and phenolates either as free species or as the corresponding metal complexes. The bare [(BINOLate)Fe]+ cation, on the other hand, preferentially loses neutral FeOH to afford an organic C20H12O+* cation radical, which most likely corresponds to ionized 1,1'-dinaphthofurane.     

三氟乙氧基磷酸酯的合成与性能研究

为提高锂离子电池安全性,本文制备了锂离子电池阻燃添加剂-三氟乙氧基磷酸酯(TFP).通过红外(IR)光谱法鉴定了产物结构;讨论了反应时间、反应物浓度比与产率的关系;以及TFP的加入对1mol/LLiPF6EC/EMC/DMC(1:1:1Vol.)电解液的可燃性、分解电压和离子电导率的影响.结果表明:反应时间、反应物浓度比对TFP产率影响较为明显,当催化剂为15mol.%(相对于三氯氧磷),反应时间6h,三氟乙醇与三氯氧磷摩尔比为6:1时,TFP的产率可以达到94.00%;添加TFP对电解液阻燃效果显著,对电解液的分解电压无不利影响,电解液电导率会有所下降,对Li/LiCoO2电池的比容量影响不大.     

Solid complexes of iron(II) and iron(III) with rutin

Solid complex compounds of Fe(II) and Fe(III) ions with rutin were obtained. On the basis of the elementary analysis and thermogravimetric investigation, the following composition of the compounds was determined: (1) FeOH(C₂₇H₂₉O₁₆)·5H₂O, (2) Fe₂OH(C₂₇H₂₇O₁₆)·9H₂O, (3) Fe(OH)₂(C₂₇H₂₉O₁₆)·8H₂O, (4) [Fe₆(OH)₂(4H₂O)(C₁₅H₇O₁₂)SO₄]·10H₂O. The coordination site in a rutin molecule was established on the basis of spectroscopic data (UV–Vis and IR). It was supposed that rutin was bound to the iron ions via 4C=O and 5C—oxygen in the case of (1) and (3). Groups 5C–OH and 4C=O as well as 3′C–OH and 4′C–OH of the ligand participate in binding metals ions in the case of (2). At an excess of iron(III) ions with regard to rutin under the synthesis conditions of (4), a side reaction of ligand oxidation occurs. In this compound, the ligands’ role plays a quinone which arose after rutin oxidation and the substitution of Fe(II) and Fe(III) ions takes place in 4C=O, 5C–OH as well as 4′C–OH, 3′C–OH ligands groups. The magnetic measurements indicated that (1) and (3) are high-spin complexes.     

Pinacol cleavage using iron(III)trisphenanthroline complexes

Oxidative bond cleavage of benzpinacol and 2,3-diphenyl-2,3- butanediol have been effected with two Fe(III)(1,10-phenanthroline)₃ complexes which are thought to undergo electron transfer reactions by an outer sphere mechanism. The products of these reactions are exclusively the corresponding ketones when 2,6-di-t-butylpyridine is added to the solution. In contrast to the facile oxidations of these aromatic substrates, pinacol is not cleaved under these reaction conditions.     

Six-coordinate nitrato complexes of iron(III) porphyrins

The interaction of tetrahydrofuran (THF) with thin films of the nitrato complexes Fe(III)(Por)(eta(2)-O(2)NO) [Por = meso-tetraphenylporphyrinato (TPP) and meso-tetratolylporphyrinato (TTP) dianion] at low temperature leads to the formation of the six-coordinate nitrato complex Fe(Por)(THF)(NO(3)), which was characterized by IR and UV-visible spectroscopies. Formation of the THF adduct was accompanied by nitrate linkage isomerization from bidentate to monodentate coordination. The iron(III) center remains in a high spin state in contrast with the previously observed low-spin nitratonitrosyl complex Fe(TPP)(NO)(eta(10-ONO(2)). Upon warming, THF dissociates to restore the initial five-coordinate bidentate nitrato complex.     

Stability constants of iron(III) borate complexes

The ultraviolet absorbance data from experiments conducted at constant pH and total iron concentration but variable B(OH)₃ concentration were used to determined the stability constants of FeB(OH) ₄ ²⁺ and Fe[B(OH)_{4 2} ⁺ at 25°C and an ionic strength of 0.68. The estimates obtained were *₁ = 1.0 ± 0.2 × 10^–2 and *₂ = 2 ± 1 × 10^–5, respectively (uncertainties are two times the standard error of the estimates). A calculation of the extent of iron(III) borate formation in ocean water at pH 8.2 shows that iron(III) borates are not a significantly large component of iron(III) speciation in seawater.     

Tris(salicylhydroxamato)manganese(III)

Summary Hydroxamic acids show a degree of selectivity towards transition metal ions having symmetrical d-electron configuration, e.g. vanadium(V) (d⁰) and iron(III) (d⁶⁵). Hydroxamato complexes of metal ions having unsymmetrical d-electron distribution are rare. Thus for manganese(III) (d⁴) only some thiohydroxamato complexes⁽¹⁾ have been characterised so far. In this communication we report on the first synthesis of a salicylhydroxamato complex of manganese(III). Such investigations are of interest because these higher valent manganese complexes are potentially models for the water-splitting complex present in photosystem II⁽²).