Treatment Of FeCl2 Research Articles

Effect of different chemical priming agents on physiological and morphological characteristics of rice (Oryza sativa L.)

The research was conducted following a Completely Randomized Design (CRD) to investigate the effects of seed priming using various chemical treatments on the germination and growth parameters of two rice cultivars, BRRI Dhan-66 and IR 80991-B-330-U-1. Ten different priming agents, including H3BO3, CaCO3, CuSO4, DAP, FeCl2, MoP, PEG (5 %), PEG (10 %), Urea, and ZnSO4, were applied to treat the seeds, each treatment being replicated three times. A control group underwent hydro-priming. The seeds were soaked in the treatments for 24 h. After the priming treatments, the seeds were subjected to a redrying process at a temperature of 26 ± 2 °C until they regained their original weight before being transplanted onto blotting paper. Germination parameters such as germination percentage, germination speed, germination energy, and vigor index were recorded for seven consecutive days. Growth parameters including root length, shoot length, fresh seedling weight, and dry seedling weight were measured at 10, 20, and 30 days after sowing. The results indicate significant variations among the treatments for germination parameters (p ≤ 0.001). Similarly, significant variations were observed in growth parameters, including shoot length, fresh weight, and dry weight (p ≤ 0.001). Among the rice varieties, BRRI Dhan-66 exhibited better results for germination percentage (81.58 %), germination speed (62.78 %), germination energy (52.06 %), vigor index (1312), fresh weight (0.807g), and dry weight of seedlings (0.053g). In contrast, the FeCl2 treatment showed the best results, inducing respective increases of 25.19 %, 93.35 %, 94.95 %, and 29.07 % for germination percentage, speed, energy, and vigor index compared to the control, respectively. For growth parameters, the DAP and CuSO4 treatments demonstrated better results. Our findings highlight that improved germination of primed rice seedlings is associated with germination energy, speed, vigor index, and the fresh weight of the seedlings. Furthermore, Pearson's correlation coefficient revealed there is significant positive correlation between germination percentage, speed, energy and vigor index but the strongest correlation exists between germination speed and germination energy (R = 0.94***) followed by germination percentage and vigor index (R = 0.92***). Based on our findings, we propose that seed priming significantly enhances rice seedlings' germination and growth parameters. BRRI Dhan-66, along with seed treatment using FeCl2, can be effectively employed to achieve improved germination and growth in rice cultivation.

Co-catalysis of magnesium chloride and ferrous chloride for xylo-oligosaccharides and glucose production from sugarcane bagasse

Inorganic salt treatment is a novel, high-yield, and environmentally friendly approach for the production of xylo-oligosaccharides from Sugarcane bagasse with degree of polymerization of 2–5. A xylo-oligosaccharides yield of 53.79% was obtained with 0.1 M MgCl2 treatment at 180 °C/10 min, and 41.89% with 0.1 M FeCl2 treatment at 140 °C/30 min. The xylo-oligosaccharides yield from the co-catalysis of 0.05 M FeCl2 + 0.05 M MgCl2 reached 54.68% (29.34% xylobiose and 20.94% xylotriose) at 140 °C/30 min. The co-catalysis not only effectively improved the xylobiose and xylotriose contents but also increased the total yield of xylo-oligosaccharides under mild reaction conditions. Additionally, the glucose yield observed from the solid residue after inorganic salt treatment was 71.62% by enzymatic hydrolysis. Mg2+ and Fe2+ are essential for good human health without separation from the system, therefore, the inorganic salt treatment can be potentially applied in the co-production of xylo-oligosaccharides and glucose.

Iron Pincer Complexes Incorporating Bipyridine: A Strategy for Stabilization of Reactive Species

Treatment of FeCl2(thf)1.5 with the pincer ligand bis(dicyclohexylphosphinomethyl)pyrrolide (CyPNP) in the presence of 2,2′-bipyridine (bipy) affords the six-coordinate complex [FeCl(bipy)(CyPNP)]. The chloride complex exhibits spin-crossover behavior and serves as a starting point for a series of bipy-coordinated iron(II) pincer compounds, including the hydride species [FeH(bipy)(CyPNP)]. Chemical reduction of [FeCl(bipy)(CyPNP)] generates the new complex [Fe(bipy)(CyPNP)], which is found to be consistent with a structure featuring iron(I) as opposed to a bipy radical anion. Reactivity studies with the bipy complexes demonstrate that they are more prone to migratory insertion and β-hydrogen elimination reactions than the corresponding dicarbonyl analogues and that in certain instances the bipy ligand can be sequestered by treatment with a Lewis acid. These observations demonstrate that coordination of bipyridine to pincer-ligated iron(II) species provides a means of stabilizing otherwise unstable compoun...

Iron and ruthenium complexes having a pincer-type ligand with two protic amidepyrazole arms: Structures and catalytic application

This paper describes the iron and ruthenium complexes ligated by 2,6-di(5-pivalamido-1H-pyrazol-3-yl)pyridine (amide-LH2) bearing electron-withdrawing NHCOBut groups on the two protic pyrazole arms. Treatment of FeCl2·4H2O with an equimolar amount of amide-LH2 followed by addition of two trimethylphosphine and an excess of sodium triflate gave the pincer-type iron complex [Fe(MeCN)(amide-LH2)(PMe3)2](OTf)2 (1b; OTf=OSO2CF3). Impact of the amido groups in 1b on the reactions with hydrazines was evaluated. Complex 1b catalyzed disproportionation of hydrazine into ammonia and dinitrogen, although the catalytic activity was lower than that of the But-LH2 analogue 1a. X-ray analysis of 1b as well as the ruthenium complex [{RuCl2(PPh3)2}2(μ2-amide-LH2)2] (2b) revealed that the pendant carboxamide groups along with the pyrazole NH units are engaged in hydrogen bonds in the second coordination sphere.

A Pyrrole-Based Pincer Ligand Permits Access to Three Oxidation States of Iron in Organometallic Complexes

Treatment of FeCl2(thf)1.5 with the sodium salt of bis(dicyclohexylphosphinomethyl)pyrrole (NaCyPNP) in the presence of pyridine (py) affords the high-spin, five-coordinate iron(II) complex [FeCl(py)(CyPNP)]. The chloride complex serves as a starting point for a variety of organometallic iron(II) compounds including S = 1 square planar alkyls, [FeR(CyPNP)] (R = Me, Et, Bn, Ph). Treatment of [FeCl(py)(CyPNP)] with NaBEt3H does not generate an analogous square-planar hydride complex, but rather a bimetallic high-spin iron(II) species containing bridging hydride ligands. Analogous transmetalation reactions in the presence of carbon monoxide produced six-coordinate low-spin species [FeR(CO)2(CyPNP)] (R = Et, Ph, and H). Reduction of [FeCl(py)(CyPNP)] under CO afforded the low-spin iron(I) carbonyl complex [Fe(CO)2(CyPNP)]. This species could be further reduced with KC8 to afford the anionic iron(0) complex K[Fe(CO)2(CyPNP)]·thf. The breadth of coordination numbers, spin states, and valencies supported by this...

Iron-induced oxidative stress activates AKT and ERK1/2 and decreases Dyrk1B and PRMT1 in neuroblastoma SH-SY5Y cells

Iron is essential for proper neuronal functioning; however, excessive accumulation of brain iron is reported in Parkinson’s, Alzheimer’s, Huntington’s diseases and amyotrophic lateral sclerosis. This indicates that dysregulated iron homeostasis is involved in the pathogenesis of these diseases. To determinate the effect of iron on oxidative stress and on cell survival pathways, such as AKT, ERK1/2 and DyrK1B, neuroblastoma SH-SY5Y cells were exposed to different concentration of FeCl2 (iron). We found that iron induced cell death in SH-SY5Y cells in a concentration-dependent manner. Detection of iNOS and 3-nitrotyrosine confirms the presence of increased nitrogen species. Furthermore, we found a decrease of catalase and protein arginine methyl-transferase 1 (PRMT1). Interestingly, iron increased the activity of ERK and AKT and reduced DyrK1B. Moreover, after FeCl2 treatment, the transcription factors c-Jun and pSmad1/5 were activated. These results indicate that the presence of high levels of iron increase the vulnerability of neurons to oxidative stress.

Study of Anti-Fatigue Effect in Rats of Ferrous Chelates Including Hairtail Protein Hydrolysates.

The ability of ferrous chelates including hairtail protein hydrolysates to prevent and reduce fatigue was studied in rats. After hydrolysis of hairtail surimi with papain, the hairtail protein hydrolysates (HPH) were separated into three groups by range of relative molecular weight using ultrafiltration membrane separation. Hairtail proteins were then chelated with ferrous ions, and the antioxidant activity, the amino acid composition and chelation rate of the three kinds of ferrous chelates including hairtail protein hydrolysates (Fe-HPH) were determined. Among the three groups, the Fe-HPH chelate showing the best conditions was selected for the anti-fatigue animal experiment. For it, experimental rats were randomly divided into seven groups. Group A was designated as the negative control group given distilled water. Group B, the positive control group, was given glutathione. Groups C, D and E were designated as the Fe-HPH chelate treatment groups and given low, medium, and high doses, respectively. Group F was designated as HPH hydrolysate treatment group, and Group G was designated as FeCl2 treatment group. The different diets were orally administered to rats for 20 days. After that time, rats were subjected to forced swimming training after 1 h of gavage. Rats given Fe-FPH chelate had higher haemoglobin regeneration efficiency (HRE), longer exhaustive swimming time and higher SOD activity. Additionally, Fe-FPH chelate was found to significantly decrease the malondialdehyde content, visibly enhance the GSH-Px activity in liver and reduce blood lactic acid of rats. Fe-HPH chelate revealed an anti-fatigue effect, similar to or better than the positive control substance and superior to HPH or Fe when provided alone.

Synthesis and protonation of an encumbered iron tetraisocyanide dianion.

Reported here are synthetic studies probing highly reduced iron centers in an encumbering tetraisocyano ligand environment. Treatment of FeCl2 with sodium amalgam in the presence of 2 equiv of the m-terphenyl isocyanide CNAr(Mes2) (Ar(Mes2) = 2,6-(2,4,6-Me3C6H2)2C6H3) produces the disodium tetraisocyanoferrate Na2[Fe(CNAr(Mes2))4]. Structural characterization of Na2[Fe(CNAr(Mes2))4] revealed a tight ion pair, with the Fe center adopting a tetrahedral coordination geometry consistent with a d(10) metal center. Attempts to disrupt the cation-anion contacts in Na2[Fe(CNAr(Mes2))4] with cation-sequestration reagents lead to decomposition, except for the case of 18-crown-6, where a mononuclear complex featuring a dianionic 1-azabenz[b]azulene ligand was isolated in low yield. Formation of this 1-azabenz[b]azulene is rationalized to proceed by an aza-Büchner ring expansion of a CNAr(Mes2) ligand mediated by a coordinatively unsaturated Fe center. Disodium tetraisocyanoferrate Na2[Fe(CNAr(Mes2))4] is readily protonated by trimethylsilanol (HOSiMe3) to produce the monohydride ferrate salt, Na[HFe(CNAr(Mes2))4], the anionic portion of which serves as an isocyano analogue of the hydrido-tetracarbonyl metalate [HFe(CO)4](-). Treatment of Na[HFe(CNAr(Mes2))4] with methyl triflate (MeOTf; OTf = [O3SCF3](-)) at low temperature in the presence of dinitrogen yields the five-coordinate Fe(0) complex Fe(N2)(CNAr(Mes2))4. The formation of Fe(N2)(CNAr(Mes2))4 in this reaction is consistent with the intermediacy of the neutral tetraisocyanide Fe(CNAr(Mes2))4. The decomposition of Fe(N2)(CNAr(Mes2))4 to the dimeric complex [Fe(η(6)-(Mes)-μ(2)-C-CNAr(Mes))]2 and a seven-membered cyclic imine derived from a CNAr(Mes2) ligand is presented and provides insight into the ability of CNAr(Mes2) and related m-terphenyl isocyanides to stabilize zerovalent four-coordinate iron complexes in a strongly π-acidic ligand field.

Altered APP Carboxyl-Terminal Processing Under Ferrous Iron Treatment in PC12 Cells

Amyloid-β peptide (Aβ), generated by proteolytic cleavage of the amyloid precursor protein (APP), plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). The key step in the generation of Aβ is cleavage of APP by beta-site APP-cleaving enzyme 1 (BACE1). Levels of BACE1 are increased in vulnerable regions of the AD brain, but the underlying mechanism is unknown. In the present study, we reported the effects of ferrous ions at subtoxic concentrations on the mRNA levels of BACE1 and a-disintegrin-and-metalloproteinase 10 (ADAM10) in PC12 cells and the cell responses to ferrous ions. The cell survival in PC12 cells significantly decreased with 0 to 0.3 mM FeCl2, with 0.6 mM FeCl2 treatment resulting in significant reductions by about 75%. 4,6-diamidino-2-phenylindole (DAPI) staining showed that the nuclei appeared fragmented in 0.2 and 0.3 mM FeCl2. APP-α-carboxyl terminal fragment (APP-α-CTF) associations with ADAM10 and APP-β-CTF with BACE1 were increased. Levels of ADAM10 and BACE1 mRNA increased in response to the concentrations of 0.25 mM, respectively. In addition, p-ERK and p-Bad (S112, S155) expressions were increased, suggesting that APP-CTF formation is related to ADAM10/BACE1 expression. Levels of Bcl-2 protein were increased, but significant changes were not observed in the expression of Bax. These data suggest that ion-induced enhanced expression of AMDA10/BACE1 could be one of the causes for APP-α/β-CTF activation.

Bis(isothiocyanato)iron(II) complexes with bithiazole ligands: Structure and magnetic studies

Two new mononuclear iron(II) complexes, [Fe(4bt)2(NCS)2] (1) and [Fe(dm4bt)2(NCS)2] (2), were prepared from the treatment of FeCl2·4H2O and KSCN salts with 4,4′-bithiazole (4bt) and 2,2′-dimethyl-4,4′-bithiazole (dm4bt), respectively and their structures and magnetisms were studied. Crystal structure determination revealed similar distorted octahedral [FeN6] moiety for both high spin iron(II) complexes. Fe–N distances are seen in 1 and 2 to be in the range of 2.085(8)–2.173(3) for Fe–NNCS and 2.178(3)–2.279(7)Å for Fe–Nbt which is consistent with the assigned iron spin and oxidation states. Temperature dependent χmT showed that the complexes are magnetically resembled and behave as S=2 systems with some zero-field splitting. Complexes 1 and 2 were also studied in solution by means of 1H NMR and UV–Vis spectroscopy techniques.

The dependence of Ni-Fe bioxide composites nanoparticles on the FeCl2 solution used.

BackgroundNi2O3- γ-Fe2O3 composite nanoparticles coated with a layer of 2FeCl3·5H2O can be prepared by co-precipitation and processing in FeCl2 solution. Using vibrating sample magnetometer (VSM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) diffraction techniques, the dependence of the preparation on the concentration of the FeCl2 treatment solution is revealed.ResultsThe magnetization of the as-prepared products varied non-monotonically as the FeCl2 concentration increased from 0.020 M to 1.000 M. The Experimental results show that for the composite nanoparticles, the size of the γ-Fe2O3 phase is constant at about 8 nm, the Ni2O3 phase decreased and the 2FeCl3·5H2O phase increased with increasing concentration of FeCl2 solution. The magnetization of the as-prepared products mainly results from the γ-Fe2O3 core, and the competition between the reduction of the Ni2O3 phase with the increase of the 2FeCl3·5H2O phase resulted in the apparent magnetization varying non-monotonically.ConclusionsWhen the concentration of FeCl2 treatment solution did not exceed 0.100 M, the products are spherical nanoparticles of size about 11 nm; their magnetization increased monotonically with increasing the concentration of FeCl2 solution due to the decreasing proportion of Ni2O3 phase.

Synthesis and Structural Characterization of Lithium and Iron Complexes Containing a Chelating Phenolate Phosphane Ligand

AbstractThe preparation and characterization of lithium and iron(II) complexes containing a potentially tridentate biphenolate phosphane ligand are reported. Deprotonation of 2,2′‐phenylphosphanyl‐bis(4,6‐di‐tert‐butylphenol) (H2LPh) with one or two equivalents of nBuLi in diethyl ether solutions at –35 °C produces binuclear {Li(HLPh)(OEt2)}2 or tetranuclear Li4(LPh)2(OEt2)3, respectively. An X‐ray study of {Li(HLPh)(OEt2)}2 showed it to be a Ci‐symmetric dimer composed of two Li(HLPh)(OEt2) units linked with dative O–Li bonds involving phenolate oxygen donor atoms whereas that of Li4(LPh)2(OEt2)3 revealed a C2‐symmetric structure in which the two biphenolate phosphane ligands are linked with four lithium atoms that bind to three diethyl ether molecules. Treatment of FeCl2 with one or two equivalents of Na2(LPh)(DME)2 in THF at –35 °C generates binuclear Fe2(LPh)2(THF)2 or mononuclear Fe(HLPh)2(THF)2, respectively. The two iron(II) centers in Fe2(LPh)2(THF)2 are antiferromagnetically coupled.

A Continuous Symmetry Measure of [4Fe−4S]+ Core Distortions and Analysis of Supramolecular Synthons in Crystal Structures of (Et4N)3[Fe4S4Cl4]·Et4NCl at 100 and 295 K

Distortions of the [4Fe-4S](+) cores of synthetic models from T(d) symmetry are analyzed in terms of the continuous symmetry measures (CSM, S(T(d))), and these are related to lattice effects in terms of the supramolecular synthon terminology common to crystal engineering of small molecule structures. The small tetragonal compression to D(2d) from idealized T(d) symmetry observed at low temperature is attributed to environmental factors. New members of the isomorphous series of compositional variations of double salts of the air-sensitive reduced cluster (Et(4)N)(3)[Fe(4)S(4)Cl(4)].Et(4)NCl (1) are prepared in modest yield by treatment of FeCl(2) with NaHS, or (Et(4)N)(2)[FeCl(4)] with Et(4)NSH and a base. The crystals are isomorphous with the corresponding HS(-) ligated cluster. Crystal data: tetragonal, P42(1)c, Z = 2, a = b = 12.2550 (4), c = 16.278 (1) A at 100 K, and a = b = 12.385 (1), c = 16.344 (2) A at 295 K. The crystallographically imposed S(4) symmetry obtained with sterically unincumbering ligands affords a better view of the intrinsic geometry of the core structure. The cocrystallization of the halide ion affords the opportunity to compare three types of weak C-H...X hydrogen bonds, or hydrogen bridges, between tetraalkylammonium cations and anions within the same crystal lattice. The C...Cl(-) distances (3.590 and 3.634 at 100 K increase to 3.616 and 3.655 A, respectively, at 295 K) are virtually temperature independent, indicative of hard hydrogen bridges, whereas the C...Cl-Fe distances are 3.702-3.718 A at 100 K but are 3.753-3.764 A at room temperature, suggesting a softer hydrogen bridge. A similar trend applies to the two sets of C...mu(3)-S distances (3.766-3.788 A and 3.594-3.604 A at 100 K and 3.821-3.848 A and 3.614-3.676 A at room temperature). The longer hydrogen bridges are more linear (170 degrees ) than the shorter ones (134 degrees ). The core distortions are correlated with spatial distribution of cations around the clusters.

Preparation and Evaluation of GAC-Based Iron-Containing Adsorbents for Arsenic Removal

Granular activated carbon-based, iron-containing adsorbents (As-GAC) were developed for effective removal of arsenic from drinking water. Granular activated carbon (GAC) was used primarily as a supporting medium for ferric iron that was impregnated by ferrous chloride (FeCl2) treatment, followed by chemical oxidation. Sodium hypochlorite (NaClO) was the most effective oxidant, and carbons produced from steam activation of lignite were most suitable for iron impregnation and arsenic removal. Two As-GAC materials prepared by FeCl2 treatment (0.025 -0.40 M) of Dacro 20 x 50 and Dacro 20 x 40LI resulted in a maximum impregnated iron of 7.89% for Dacro 20 x 50 and 7.65% for Dacro 20 x 40Ll. Nitrogen adsorption-desorption analyses showed the BET specific surface area, total pore volume, porosity, and average mesoporous diameter all decreased with iron impregnation, indicating that some micropores were blocked. SEM studies with associated EDS indicated that the distribution of iron in the adsorbents was mainly on the edge of As-GAC in the low iron content (approximately 1% Fe) sample but extended to the center at the higher iron content (approximately 6% Fe). When the iron content was > approximately 7%, an iron ring formed at the edge of the GAC particles. No difference in X-ray diffraction patterns was observed between untreated GAC and the one with 4.12% iron, suggesting that the impregnated iron was predominantly in amorphous form. As-GAC could remove arsenic most efficiently when the iron content was approximately 6%; further increases of iron decreased arsenic adsorption. The removal of arsenate occurred in a wide range of pH as examined from 4.4 to 11, but efficiency was decreased when pH was higher than 9.0. The presence of phosphate and silicate could significantly decrease arsenate removal at pH > 8.5, while the effects of sulfate, chloride, and fluoride were minimal. Column studies showed that both As(V) and As(III) could be removed to below 10 microg/L within 6000 empty bed volume when the groundwater containing approximately 50 microg/L of arsenic was treated.

Tuning low-coordinate metal environments: high spin d5–d7 complexes supported by bis(phosphinimino)methyl ligation

Treatment of FeCl2 with the lithium derivative of [CH2(Ph2PNC6H2Me3-2,4,6)2] in THF and crystallisation from Et2O gave the ‘ate’ complex [{CH(Ph2PNC6H2Me3-2,4,6)2}Fe(μ-Cl)2Li(THF)(OEt2)] in which the iron is four-coordinate and the chlorides bridge to lithium. Treatment of [M{N(SiMe3)}2] (M = Mn, Fe, Co) with [CH2(Ph2PNC6H2Me3-2,4,6)2] in toluene afforded the complexes [{CH(Ph2PNC6H2Me3-2,4,6)2}MN(SiMe3)2] which all feature essentially planar N(1)–N(2)–N(3)–M coordination. The carbanionic character of the bis(phosphinimino)methyl ligand results in close C(1)–M contacts in both the Mn and Co complexes effectively raising the coordination number to four. The analogous iron compound is strictly three-coordinate as demonstrated by X-ray crystallography and 57Fe Mossbauer. However protonolysis of this compound with Ph3COH yields the iron alkoxide [{CH(Ph2PNC6H2Me3-2,4,6)2}FeOCPh3] that features a close C(1)–Fe contact of 2.375 A. Although the iron centre in this complex is only marginally pyramidalised by this contact, its 57Fe Mossbauer spectrum indicates a significant perturbation to the local electronic environment at the metal.

Synthesis, Structure and Reactivity of Sulfur‐Rich [Fe(L1)(L2)(‘tpS4’)] Complexes with Rigid [Fe(‘tpS4’] Cores and σ−π Co‐Ligands (‘tpS4’2− = 1,2‐Bis(2‐mercaptophenylthio)phenylene(2−); L1, L2 = CO, PR3, NO)

AbstractOptimisation of synthesis and purification steps has made the new ligand ‘tpS4’2− available in preparative amounts. Treatment of FeCl2·4H2O with ‘tpS4’‐Li2 or ‘tpS4’‐Na2 yielded [Fe(‘tpS4’)] (1), which in the solid state and in the absence of co‐ligands probably trimerises to give paramagnetic [Fe(‘tpS4’)]3. The [Fe(‘tpS4’)] fragment displays helical coordination of the ‘tpS4’2− ligand and binds σ−π ligands such as CO, NO and phosphanes to give diamagnetic 18‐valence‐electron complexes of general formula [Fe(L1)(L2)(‘tpS4’)]. The cis‐dicarbonyl complex [Fe(CO)2(‘tpS4’)] (2) is labile and readily dissociates CO to give dinuclear [Fe(CO)(‘tpS4’)]2 (3). Simultaneous coordination of CO and phosphanes yielded [Fe(CO)(PR3)(‘tpS4’)] with R = Me (4), Et (5), Pr (6) and Bu (7), but it proved impossible to obtain analogous complexes with bulky PPh3 or PCy3 ligands. Bis(phosphane) complexes could be obtained only with PMe3 and the bidentate dppe, which yielded [Fe(PMe3)2(‘tpS4’)] (8) and [Fe(dppe)(‘tpS4’)] (11). Alkylphosphanes with longer alkyl substituents, such as PnPr3 and PnBu3, gave the labile derivatives [Fe(PR3)2(‘tpS4’)] with R = nPr (9) and nBu (10). Complexes 9 and 10 reversibly dissociate one PR3 ligand, yielding diamagnetic [Fe(PR3)(‘tpS4’)] fragments. These findings explain the decisive and hitherto inexplicable influence of PPr3 and PBu3 ligands upon the stabilisation of N2H2 in the diazene complexes [μ‐N2H2{Fe(PR3)(‘tpS4’)}2] with R = Pr, Bu. Treatment of [Fe(‘tpS4’)] (1) or [Fe(CO)(‘tpS4’)]2 (3) with NO or NO+ yielded [Fe(NO)2(‘tpS4’)] (12). The molecular structures of 3, 4, 7 and 8 were determined by X‐ray structure analysis. Spectroscopic and structural results indicate that the differences in reactivity between [Fe(L1)(L2)(‘tpS4’)] and homologous [Fe(L1)(L2)(‘S4’)] complexes can be traced back to subtle electronic and structural effects. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Organically Templated Inorganic/Organic Hybrid Materials: Synthesis and Structures of (C4H12N2)[FeII4(C2O4)3(HPO4)2] and (C5H14N2)[FeIII2(C2O4)(HPO4)3

Hydrothermal treatment of FeCl2·4H2O (or FeCl3·6H2O) and piperazine (or 2-methylpiperazine) with H3PO4 and H2C2O4 in H2O yields two organically templated compounds. The 3-D frameworks are constructed from FeII−O (or FeIII−O) polyhedra and two different ligands, phosphate and oxalate, both coordinated to the iron atoms. The structure of the FeIII compound is shown.

Synthesis, Resolution, and Crystallographic Characterization of a C2-Symmetric Diphosphaferrocene

Treatment of FeCl2 with potassium 2-phenyl-3,4-dimethylphospholide provides a new C2-symmetric diphosphaferrocene, (±)-3,3‘,4,4‘-tetramethyl-2,2‘-diphenyl-1,1‘-diphosphaferrocene (1). Separation by chiral HPLC furnishes both antipodes of complex 1, the first diphosphaferrocene to be prepared in enantiopure form. The absolute configuration of (−)-1 has been determined by X-ray crystallography.

ChemInform Abstract: TRANSITION‐METAL‐PROMOTED OXIDATIVE FUSION WITH CARBORANE AND BORANE ANIONS. SYNTHESIS OF C4BN (N = 8‐11) CARBORANE SYSTEMS IN THE PRESENCE OF B5H8‐ AND B3H8‐ IONS

AbstractDie simultane Behandlung des Carborananions (I) mit B 5Hg und COCl2 liefert den luftstabilen, kristallinen Komplex (II) als isolierbares Hauptprodukt.