Electronic and infrared spectral studies of manganese(III) selenito complexes

Summary Selenito manganese(III) complexes of the type MMn(SeO₃)₂ · × H₂O (where M = H⁺, NH ₄ ⁺ , K⁺, Rb⁺ and Cs⁺) have been prepared, Magnetic measurements show all these complexes to be of high spin d⁴ type, On the basis of their i.r. and electronic spectral studies and other properties, a polymeric octahedral structure involving bridging oxygen atoms has been suggested.     

Nitrosyl Rhenium Complexes: Thiocyanato Derivatives

Fusion of K₂[Re(NO)Cl₅] with KSCN produces the ion [Re(NO)(SCN)₅]^2? which has been isolated as free acid and K⁺, Na⁺, NMe₄⁺, Pb²⁺, Hg²⁺, phen H⁺ and dipyH⁺ salts. A salt of composition Hg₂[Re(NO)(SCN)₇] has also been prepared. The species [Re(NO)Cl(SCN)₄]^2? has been obtained from the reaction of H₂[Re(NO)(SCN)₅] with HCl in aqueous medium and its NMe₄⁺ salt has been isolated. Hydrated Re(NO)Cl₃ reacts with KSCN in aqueous medium to produce the ion [Re(NO)Cl₂(SCN)₃]^2? which has been isolated as its phenH⁺ and dipyH⁺ salts. The complexes have been characterized through elemental analyses, spectral (u.v., vis., i.r.) properties, magnetic and conductance data. The structures of all those compounds have been proposed.     

球形PVC-MnO2离子筛的制备及锂吸附性能

本实验室前期所制备的Li4Mn5O12超细粉末在卤水体系中对Li+具有较大的吸附容量和良好的选择性。但由于超细粉体的流动性和渗透性差,无法直接应用于固定床,需对粉末吸附材料进行成型造粒,以便于实际应用。本论文采用聚氯乙烯为粘结剂,制备出粒径约为2.0~3.5 mm的球形PVC-Li4Mn5O12,经盐酸处理后得到球形PVC-MnO2离子筛。并通过扫描电镜(SEM)、X射线衍射仪(XRD)、静态和动态连续锂吸附实验研究了球形离子筛形貌和锂离子吸附性能。结果表明,球形离子筛对Li+的吸附容量高达5.28 mmol.g-1,在混合溶液中对Li+具有良好的选择性,这对于在盐湖卤水或海水提锂具有重要的实用意义。     

Synthesis of Cationic R2P5+ Cages and Subsequent Chalcogenation Reactions

Cationic R₂P₅⁺ cage compounds ( 1 ⁺) have been synthesized by the stoichiometric reaction of R₂PCl, GaCl₃ and P₄. The reaction conditions depend on the substituent R. Alkyl‐substituted derivatives ( 1 a – 1 d [GaCl₄]) are best synthesized under solvent‐free conditions, whereas aryl‐substituted derivatives ( 1 e – 1 h [GaCl₄]) are formed in C₆H₅F. All compounds have been prepared on a multi‐gram scale in good to excellent yields and have been fully characterized with an emphasis on ³¹P NMR spectroscopy in solution and single‐crystal structure determination. Subsequent chalcogenation reactions of cations R₂P₅⁺ ( 1 a ⁺, 1 e ⁺) and trication Ph₆P₇³⁺ ( 3 ³⁺) with elemental sulfur (α‐S₈) or grey selenium (Se_grey) yielded a series of unique polyphosphorus–chalcogen cations ( 4 a ⁺, 4 e ⁺, 5 a ⁺, 6 ²⁺ and 7 ²⁺), possessing nortricyclane‐type molecular structures. An in‐depth study of the ³¹P{¹H} and ⁷⁷Se NMR spectroscopic parameters is presented, and correlations between the substitution pattern and the observed structural features have been investigated in detail.     

Crystal structure of salts of the trans-[Rh(NH3)2(NO2)4]− anion with K+, Cs+, Ag+, and (CH3)4N+ cations

Complex rhodium(III) salts with the composition trans-M[Rh(NH₃)₂(NO₂)₄], where M = K⁺, Cs⁺, Ag⁺, and N(CH₃) ₄ ⁺ , are prepared and characterized. The molecular and crystal structures are determined by X-ray crystallography.     

Nitrosyl Rhenium Complexes Syntheses,Properties, and Structures of Oxalato Derivatives

The free acid, H[Re(NO)(C₂O₄)(OH)₂(H₂O)] has been prepared from the reaction of Re(NO)(OH)₃ ? H₂O with oxalic acid in aqueous medium. The K⁺, NH₄⁺ and Pb²⁺ salts of the acid have been isolated. Nonelectrolytic diimino derivatives, Re(NO)(C₂O₄)X · L (X = 1, 10-phenanthroline, 2,2′-dipyridyl; L ? OH^?, Cl^?) have been synthesized. The complexes have been characterised through elemental analyses, spectral (u.v., vis., i.r.) properties, magnetic and conductance data and their structures are proposed.     

Characterization of five [C4H7O]+ Ion structures. Fragmentation of the 2-pentanone molecular ion

The [C₄H₇0]⁺ ions [CH₂?CH? C(?OH)CH₃]⁺ (1), [CH₃CH?CH? C(?OH)H]⁺ (2), [CH₂?C(CH₃)C(?OH)H]⁺ (3), [Ch₃CH₂CH₂C?O]⁺ (4) and [(CH₃)₂CHC?O]⁺ (5) have been characterized by their collision-induced dissociation (CID) mass spectra and charge stripping mass spectra. The ions 1–3 were prepared by gas phase protonation of the relevant carbonyl compounds while 4 and 5 were prepared by dissociative electron impact ionization of the appropriate carbonyl compounds. Only 2 and 3 give similar spectra and are difficult to distinguish from each other; the remaining ions can be readily characterized by either their CID mass spectra or their charge stripping mass spectra. The 2-pentanone molecular ion fragments by loss of the C(1) methyl and the C(5) methyl in the ratio 60:40 for metastable ions; at higher internal energies loss of the C(1) methyl becomes more favoured. Metastable ion characteristics, CID mass spectra and charge stripping mass spectra all show that loss of the C(1) methyl leads to formation of the acyl ion 4, while loss of the C(5) methyl leads to formation of protonated vinyl methyl ketone (1). These results are in agreement with the previously proposed potential energy diagram for the [C₅H₁₀O]⁺˙ system.     

Synthesis,binding properties and electrochemistry of nickel(II) macrocyclic complexes containing crown ethers

Macrotetracyclic complexes of nickel(II) containing crown ethers as pendant arms, [Ni(B)](ClO₄)₂ and [Ni(C)](ClO₄)₂, were prepared and characterized. The binding constants of the complexes toward alkali metal ions are relatively small compared with those of free 15-crown-5 or 18-crown-6 and the reduction potentials of the [Ni(B)](ClO₄)₂ and [Ni(C)](ClO₄)₂ in the presence of alkali metal ions shift to the positive direction in the order Li⁺>Na⁺>K⁺ and K⁺>Na⁺>Li⁺, respectively.     

Platinum(II) and platinum(IV) complexes of 2-amino-4, 6-dimethylpyrimidine

Summary Platinum(II) and platinum(IV) complexes of 2-amino-4, 6-dimethylpyrimidine, ADMPY, have been prepared. Solids of formula Pt(ADMPYH⁺)Cl₃, Pt(ADMPY)₂Cl₄ and Pt(ADMPY)₂Cl₄·2HCl have been isolated and characterized by elemental analyses in conjuction with i.r. and n.m.r. spectra. A paramagnetic tan to reddishbrown complex has been reproducibly prepared from the direct reaction of K₂PtCl₄ and ADMPY at pH 6.     

Etude structurale par spectrometrie infrarouge et raman des composes de coordination: bis(pyridine)- trichloro aluminium(III) et bis(pyridine)tribromo aluminium(III)

The compounds AlX₃-2Py (X = Cl or Br, Py = C₅H₅N or C₅D₅N) have been prepared by using a method based on an exchange of organic ligands. The infrared and Raman spectra, which have been recorded between 50 and 4000 cm^?1, give strong evidence for the existence of the anion AlCl₄^? (or AlBr₄^?) and show that the cation is AlX₂(Py)⁺₄. The comparison of the spectra with those of the compound NiX₂(Py)₄., and of the cations trans-AlX₂(THF)₄⁺ and cis-AlX₂(bipy)₂⁺ indicates that the cation AlX₂(Py)₄⁺ has the helical configuration (helical trans-octahedron) and allows the assignment of the vibrations.     

Photoionization and Dissociation Study of 2-Methyl-2-propen-1-ol: Experimental and Theoretical Insights

The photoionization and dissociation of 2-methyl-2-propen-1-ol (MPO) have been investigated by using molecular beam experimental apparatus with tunable vacuum ultravioletsynchrotron radiation in the photon energy region of 8.0-15.5 eV. The photoionization efficiency (PIE) curves for molecule ion and fragment ions: C₄H₈O⁺、C₄H₇O⁺、C₃H₅O⁺、C₄H₇⁺、C₄H₆⁺、C₄H₅⁺、C₂H₄O⁺、C₂H₃O⁺、C₃H₆⁺、C₃H₅⁺、C₃H₃⁺、CH₃O⁺、CHO⁺ have been measured, and the ionization energy (IE) and the appearance energies (AEs) of the fragment ions have been obtained. The stable species and the first order saddle points have been calculated on the CCSD(T)/cc-pvTZ//B3LYP/6-31+G(d,p) level. With combination of theoretical and experimental results, the dissociative photoionization pathways of 2-methyl-2-propen-1-ol are proposed. Hydrogen migrations within the molecule are the dominant processes in most of the fragmentation pathways of MPO.     

K⋅⋅⋅F/O Interactions Bridge Copper(I) Fluorinated Alkoxide Complexes and Facilitate Dioxygen Activation

Seven E[Cu(OR)₂] copper(I) complexes (E=K⁺, {K(18C6)}⁺ (18C6=[18]crown‐6), or Ph₄P⁺; R=C₄F₉, CPhMe^F₂, and CMeMe^F₂) have been prepared and their reactivity with O₂ studied. The K[Cu(OR)₂] species react with O₂ in a copper‐concentration‐dependent manner such that 2:1 and 3:1 Cu/O₂ adducts are observed manometrically at ?78 °C. Analogous reactivity with O₂ is not observed with the {K(18C6)}⁺ or Ph₄P⁺ derivatives. Solution conductivity data demonstrate that these K[Cu(OR)₂] complexes do not behave as 1:1 electrolytes in solution. The K⁺ ions induce aggregation of multiple [Cu(OR)₂]^? units through K???F/O interactions and thereby effect irreversible O₂ reduction by multiple Cu centers. Bond valence analyses for the potassium cations confirm the dominance of the fluorine interactions in the coordination spheres of K⁺ ions. Intramolecular hydroxylation of ligand aryl and alkyl C? H bonds is observed. Nucleophilic reactivity with CO₂ is observed for the oxygenated Cu complexes and a Cu^II carbonate has been isolated and characterized.     

Adsorption of tracer cations,and the separation of carrier-free95Nb from95Zr,XU1 from U and45Ca from46Sc on titanium phosphate column

Titanium phosphate as ion exchanger for column operation has been prepared by mixing TiCl₄ and H₃PO₄ in suitable proportion. The ratio of titanium: phosphate was obtained to be 1:2.02. The uptake of Na⁺, K⁺, Rb⁺, Cs⁺, Ag⁺, Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, Sc³⁺, Co³⁺, Y³⁺, Tb³⁺, Zr⁴⁺ and Th⁴⁺ cations at very small concentrations has been studied on this exchanger. The data indicated that the different cations are adsorbed in the exchanger by different mechanisms. Radiochemical separations of carrier free⁹⁵Nb from⁹⁵Zr, UX₁ from U and⁴⁵Ca from⁴⁶Sc have been achieved by adopting very simple chemical procedures through a column of titanium phosphate. The -spectrum of the separated⁹⁵Nb, UX₁ and⁴⁶Sc showed that the products are of high radionuclidic purity. The individual separation procedures took less than 20 min and the yields are quantitative.     

Preparation of tetra-n-butylammonium peroxydisulfate. Novel tetrahydrofuranylation [1] and tetrahydropyranylation of alcohols

Tetra-n-butylammonium peroxydisulfate (Bu₄N^{+ −}OS(O₂)O–O(O₂)SO^{− +}NBu₄: (TBA)₂S₂O₈) has been successfully prepared and turned out to be a useful source of the tetra-n-butylammonium sulfate radical in organic solvents. Primary, secondary, and tertiary alcohols containing functional groups, such as benzylic, allylic, and sulfide, reacted with tetrahydrofuran or tetrahydropyran in the presence of (TBA)₂S₂O₈ to give the corresponding 2-tetrahydrofuranyl- or 2-tetrahydropyranyl-ether in excellent yields under nearly neutral conditions.     

On the tri-n-octylammonium chloro complexes of Cu(II), Zn(II) and Co(II) in benzene solution

Extracts with tri-n-octylammonium chloro complexes of Cu(II), Zn(II) and Co(II) of various compositions, including the N-deuterated compounds, were prepared and investigated by IR spectroscopy and conductivity measurements. Besides the well-known 2:1-complexes (TOAH⁺)₂MCl₄^2?, for which new assignments of νNH frequencies are given, complexes with a stoichiometric ratio TOA:M > 2 were found. Their cations contain the groups (TOAH …Cl…HTOA)⁺ and TOAH⁺ and they are supposed to be 3:1-complexes (TOAH…Cl…HTOA)⁺TOAH⁺MCl₄^2?. The IR spectrum of the 1:1-complex TOAH⁺CuCl_3? is given. The occurrence of the analogous 1:1-complex TOAH⁺ZnCl_3? could not be detected under the preparative conditions used.     

Base‐Stabilized [PO]+/[PO2]+ Cations

The salts [(BAC)₂PO][BF₄] ( 5 ) and [(BAC)₂PO₂][BF₄] ( 4 ) (BAC=bis(diisopropylamino) cyclopropenylidene), consisting of the PO⁺ and PO₂⁺ cations, respectively, coordinated to the singlet carbenes, have been prepared. Computational investigations reveal that the electronic structure of the PO⁺ cation is a hybrid between the charge‐localized and charge‐delocalized resonance forms, resulting in ambiphilic reactivity. Compound 5 reacts as a donor with the transition‐metal complex K₂PtCl₄ to furnish [[(BAC)₂PO]₂PtCl₂][BF₄]₂ ( 6 ) and KCl. Remarkably, both 5 and 4 have shown to act as electrophiles undergoing reactions with fluoride anion, leading to [OPF₂]^? and (BAC)PO₂F, respectively.     

以PEO为基质的离子及质子导电聚合物电解质

本文以PEO-LiClO₄为基质,在其中加入适量的纳米氧化锌及氧化锡,制备PEO-LiClO₄-ZnO及PEO-LiClO₄-SnO₂离子导电聚合物电解质膜,测定了复合电解质膜的电导率,并探讨了纳米粒子与PEO链的相互作用,提出复合电解质膜的电导率提高的主要影响因素。本文还合成以PEO为基质的PEO-12-钨硅酸质子导电聚合物电解质膜,讨论12-钨硅酸的加入对PEO的构型及Keggin离子的影响并分析PEO-12-钨硅     

Methane Activation by Diatomic Molybdenum Carbide Cations

Metal carbide species have been proposed as a new type of chemical entity to activate methane in both gas‐phase and condensed‐phase studies. Herein, methane activation by the diatomic cation MoC⁺ is presented. MoC⁺ ions have been prepared and mass‐selected by a quadrupole mass filter and then allowed to interact with methane in a hexapole reaction cell. The reactant and product ions have been detected by a reflectron time‐of‐flight mass spectrometer. Bare metal Mo⁺ and MoC₂H₂⁺ ions have been observed as products, suggesting the occurrence of ethylene elimination and dehydrogenation reactions. The branching ratio of the C₂H₄ elimination channel is much larger than that of the dehydrogenation channel. Density functional theory calculations have been performed to explore in detail the mechanism of the reaction of MoC⁺ with CH₄. The computed results indicate that the ethylene elimination process involves the occurrence of spin conversions in the C?C coupling (doublet→quartet) and hydrogen atom transfer (quartet→sextet) steps. The carbon atom in MoC⁺ plays a key role in methane activation because it becomes sp³ hybridized in the initial stages of the ethylene elimination reaction, which leads to much lower energy barriers and more stable intermediates. This study provides insights into the C?H bond activation and C?C coupling involved in methane transformation over molybdenum carbide‐based catalysts.     

Synthesis and Characterization of Mono- and Trinuclear Complexes of BF2+ Bridged Macrocycles

Dibenzo[e,k]-2,3-bis(hydroxyimino)-1,4-dithia-7,10-diaza-2,3,8,9-tetrahydrocyclododecine (H₂L) has been prepared from 1,2-bis(o-mercaptoanilino) ethane ( 4 ) and (E,E)-dichloroglyoxime. A mononuclear complex with a metal: ligand ratio of 1:2 has been isolated for cobalt(III). The Co^III complex of H₂L has been prepared with L′ = 2,6-lutidine, and with a chlorine ion as axial ligands. In addition to that, the synthesis of a new cobalt complex which contains BF₂⁺ bridges is achieved with the bis(E,E)-dioxime ligand. The trinuclear complex of this Co^III complex has been obtained by the reaction of BF₂⁺ bridged Co^III complex with Pd[bis(benzonitrile)]Cl₂. The structures of these complexes and (E,E)-dioxime were identified by using elemental analysis, ¹H and ¹³C-NMR, IR and MS spectral data.     

ChemInform Abstract: Structural and Electrochemical Study od a New Crystalline Hydrate Iron(III) Phosphate FePO4·H2O Obtained from LiFePO4(OH) by Ion Exchange.

FePO₄·H₂O is prepared by Li⁺/H⁺ exchange from an aqueous HNO₃ suspension of LiFePO₄(OH) at about 60 °C.