Thermal stability and crosslinking of hydropolysilanes for use as silicon carbide precursors

Thermal stability of [(CH₃SiH)₃₀(C₆H₅SiCH₃)₇₀]_n a hydropolysilane copolymer, in vacuum and its crosslinking reactions with vinylic silanes as crosslinking agents was evaluated in order to obtain high yields of oxygen-free silicon carbide ceramics. It was found that the polymer was thermally stable in vacuum up to 140 °C for 20 hrs based on Fourier transform infrared spectroscopy analysis. The crosslinking reactions of the polymer occurred to various extents depending on the type of vinylic silanes used as evidenced by Fourier transform infrared spectroscopy, ultraviolet spectroscopy, gel permeation chromatography, thermogravimetry and solubility data. The additions of vinylic silanes to Si-H in the hydropolysilane were found to obey anti-Farmer's rule, despite Farmer's addition of unsaturated hydrocarbons to Si-H.     

The Chemistry of Platinum in the +3 Oxidation State

Platinum(III) is no longer an uncommon oxidation state. Numerous binuclear platinum(III) complexes have been prepared and structurally characterized over the past eight years. These include sulfate-bridged dimers of D_4h symmetry, [Pt₂(SO₄)₄L₂]²⁻, L = H₂O, DMSO; phosphate-bridged complexes [Pt₂(HPO₄)₄-(H₂O)₂]²⁻ and [Pt₂(H₂PO₄)(HPO₄)₃(py)₂]⁻; POP (H₂ P₂ O²⁻₅)-bridged ions [Pt₂-(POP)₄X₂]²⁻, X = halide; an extensive series of α-pyridonate (C₅H₄NO⁻)-bridged head-to-head and head-to-tail complexes, [Pt₂(NH₃)₄ (C₅H₄NO)₂XY]ⁿ⁻, X, Y = NO₃, NO₂, H₂O, Cl, Br; n = 2, 3; and organometallic derivatives such as [Pt₂(CH₃)₄-(CF₃CO₂)₂(4-Mepy)₂]. In all cases there is a Pt–Pt single bond of length 2.47–2.7 Å, pseudo-octahedral geometry about platinum, and two or more bridging ligands. The complexes are stable in solution and some undergo quasi-reversible two-electron redox reactions. Mononuclear platinum(III) complexes are less well characterized structurally, but have been stabilized in diamagnetic host lattices in the solid state and by macrobicyclic cage ligands in solution following pulse radiolytic or γ-irradiation of precursor platinum(II) complexes. The first unequivocal, crystallographically characterized mononuclear platinum(III) complex, [Pt(C₆Cl₅)₄]⁻, has just been reported.     

Enhanced Hydrogenation Activity and Recycling of Cationic Rhodium Diphosphine Complexes through the Use of Highly Fluorous and Weakly‐Coordinating Tetraphenylborate Anions

The effect of the nature of the anion on the performance of ionic rhodium catalysts has received little attention. Herein it is shown that the use of highly fluorous tetraphenylborate anions can enhance catalyst activity in both conventional and fluorous media. For hydrogenation catalysts of the type [Rh(COD)(dppb)][X] {COD=1,5‐cis,cis‐cyclooctadiene; dppb=1,4‐bis(diphenylphosphino)butane; X=BF₄⁻ ( 1a ), [BPh₄]⁻ ( 1b ), [B{C₆H₄(SiMe₃)‐4}₄]⁻ ( 1c ), [B{C₆H₃(CF₃)₂‐3,5}₄]⁻ ( 1d ), [B{C₆H₄(SiMe₂CH₂CH₂C₆F₁₃)‐4}₄]⁻ ( 1e ), [B{C₆H₄(C₆F₁₃)‐4}₄]⁻ ( 1f ) and [B{C₆H₃(C₆F₁₃)₂‐3,5}₄]⁻ ( 1 g )} the activity towards the hydrogenation of 1‐octene in acetone increased in the order 1c < 1b < 1e < 1a < 1d ~ 1f < 1g with 1g being twice as active as the commonly applied 1a . Despite the fluorophilic character introduced by the substituted tetraarylborate anions, the presence of some perfluoroalkyl‐substituents in the cation was still required for achieving high partition coefficients. Therefore, [Rh(COD)(Ar₂PCH₂CH₂PAr₂)][X] {Ar=C₆H₄(SiMe₂CH₂CH₂C₆F₁₃)‐4, X=[B{C₆H₃(C₆F₁₃)₂‐3,5}₄]⁻ ( 3f ); Ar=C₆H₄(SiMe(CH₂CH₂C₆F₁₃)₂)‐4 and X=[B{C₆H₄(C₆F₁₃)‐4}₄]⁻ ( 2g )} were prepared, which were active in the hydrogenation of 1‐octene, 2g even more so than 3f . Both these highly fluorous catalysts could be recycled with 99% efficiency through fluorous biphasic separation, whereas the corresponding BF₄⁻ complex of 2g ( 2a ) did not show any affinity for the fluorous phase.     

Facile and Selective Carbonylation of Methane in Superacids

The carbonylation of CH₄ with carbon monoxide in superacids HF/SbF₅ or HSO₃F/SbF₅ leads to the exclusive and quantitative formation of the acylium ion ([CH₃CO]⁺[SbF₆]⁻) with the concomitant stoichiometric formation of SbF₃.     

Electrical conductivity measurements as a microprobe for structure transitions in polysiloxane derived Si–O–C ceramics

Polysiloxanes [RSiO_1.5]_n with R=CH₃ (PMS) and C₆H₅ (PPS), respectively, were transformed to Si–O–C ceramics of variable composition and structure upon pyrolysis in inert atmosphere at 800–1500°C. The electrical conductivities of the Si–O–C ceramics in air were measured at room temperature by using a shielded two point configuration. In situ measurements of the dc-conductivity during the pyrolytic conversion from the polymer to the ceramic phase were carried out up to 1500°C with four point contacted carbon electrodes in inert atmosphere. During polymer-ceramic conversion excess carbon precipitates above 400°C (PPS)–700°C (PMS). At temperatures above 800°C (PPS) and 1400°C (PMS) coagulation and growth of the carbon clusters results in a percolation network formation. While below the percolation threshold electrical conductivity can be described according to Motts mechanism by variable-range-hopping of localized charge carriers, regular electron band conduction due to the instrinsic conductivity of turbostratic carbon (8×10⁻⁴ (Ωcm)⁻¹) predominates above. Thus, the in situ measurement of non-linear electrical property changes can be used as a microprobe of high sensivity to detect microstructural transformations during the pyrolysis of preceramic polymers.     

Performance Assessment of Some Isomers of Saturated Polycyclic Hydrocarbons for Use as Jet Fuels

The performance of jet fuel depends on the density (ρ), condensed phase heat of formation (▵_fH°(c)), and specific impulse (I_SP). Exo‐tricyclo[5.2.1.0(2,6)]decane (C₁₀H₁₆) or JP‐10 is now used as a suitable synthetic liquid jet fuel because it has the approximated values of ρ=1.1 g cm⁻³ and ▵_fH°(c)=− 123 kJ mol⁻¹ and a broad range between the melting and boiling points, i.e. T_bp–T_mp=196.2 K. This work introduces a suitable pathway for calculation of the values of ρ, ▵_fH°(c), and I_SP of 13 well‐known isomers of JP‐10 and a series of saturated polycyclic hydrocarbons with general formula of C_nH_n′ (5≤n≤12) in order to specify high performance jet fuels. Although 13 compounds have larger values of I_SP*ρ than JP‐10, only two compounds, tetraspiro[2.0.0.0.2.1.1.1]undecane and tetracyclo[3.2.0.0(2,7).0(4,6)]heptane, are suitable as jet fuels.     

Novel Silicon-Boron-Carbon-Nitrogen Materials Thermally Stable up to 2200°C

Three novel Si-C-B-N ceramic compositions, namely Si_2.9B_1.0C₁₄N_2.9, Si_3.9B_1.0C₁₁N_3.2 and Si_5.3B_1.0C₁₉N_3.4, were synthesized using the polymer-to-ceramic transformation of the polyorganoborosilazanes [B(C₂H₄Si(Ph)NH)₃]_n, [B(C₂H₄Si(CH₃)NH)₂–(C₂H₄Si(CH₃)N(SiH₂Ph))]_n, and [B(C₂H₄Si(CH₃)–N(SiH₂Ph))₃]_n, where Ph is phenyl (C₆H₅), at 1050°C in argon. The Si-B-C-N ceramics exhibited significant stability with respect to composition and mass change in the temperature range between 1000° and 2200°C, including isothermal annealing of the samples at the final temperature for 30 min in argon. The mass loss rate at 2200°C was as low as 1.4 wt%·h⁻¹ for Si_5.3B_1.0C₁₉N_3.4, 1.7 wt%·h⁻¹ for Si_2.9B_1.0C₁₄N_2.9, and 2.4 wt%·h⁻¹ for Si_3.9B_1.0C₁₁N_3.2. The measured amount of mass loss rate was comparable to that of pure SiC materials. As crystalline phases, β-Si₃N₄ and β-SiC were found exclusively in the samples annealed at 2200°C at 0.1 MPa in argon. For thermodynamic reasons, β-Si₃N₄ should have decomposed into the elements silicon and nitrogen at that particular temperature and gas pressure. However, the presence of β-Si₃N₄ in our materials indicated that carbon and boron kinetically stabilized the Si₃N₄-based composition.     

A heterobimetallic copper(I)–silver(I) complex spanned by 4,4′-bipyridine

Cationic heterobimetallic {[P(C₆H₄CH₂NMe₂-2)₃]Ag-bipy-Cu[P(C₆H₄CH₂NMe₂-2)₃]}²⁺(OTf⁻,PF₆⁻) (5) (bipy = 4,4^′-bipyridine, OTf=OSO₂CF₃) is accessible by the subsequent reaction of [P(C₆H₄CH₂NMe₂-2)₃]AgOTf (1) with bipy (2) to afford {[P(C₆H₄CH₂NMe₂-2)₃]Ag(bipy)}⁺(OTf⁻) (3), which on treatment with equimolar amounts of {[P(C₆H₄CH₂NMe₂-2)₃]Cu}⁺(PF₆⁻) (4) produces 5. In 5 the respective group-11 metal(I) centres are bridged by the π-conjugated organic ligand bipy. The electrochemical behaviour of 5 is reported.     

Ethylene polymerization by alkylidene‐bridged asymmetric dinuclear titanocene/MAO systems

Two asymmetric alkylidene‐bridged dinuclear titanocenium complexes (CpTiCl₂)₂(η⁵‐η⁵‐C₉H₆(CH₂)_nC₅H₄), 1 (n = 3) and 2 (n = 4) have been prepared by treating two equivalents of CpTiCl₃ with the corresponding dilithium salts of the ligands C₉H₇(CH₂)_nC₅H₅ (n = 3, 4). Additionally, Ti(η⁵:η⁵‐n‐BuC₅H₄C₅H₅)Cl₂ (3) and Ti(η⁵:η⁵‐n‐BuC₉H₆C₅H₅)Cl₂ (4) were synthesized as corresponding mononuclear complexes. All complexes were characterized by ¹H, ¹³C NMR, and IR spectroscopy. Homogenous ethylene polymerization catalyzation using those complexes has been conducted in the presence of methylaluminoxane (MAO). The influences of reaction parameters, such as [MAO]/[Cat] molar ratio, catalyst concentration, ethylene pressure, temperature, and time have been studied in detail. The results showed that the catalytic activities of both dinuclear titanocenes were higher than those of the corresponding mononuclear titanocenes. Although the two dinuclear complexes were different in only one [CH₂] unit, the catalytic activity of 2 was about 50% higher than that of 1; however, the molecular weight of polyethylene (PE) obtained by 2 was lower than that obtained from 1. The molecular weight distribution of PE produced by these dinuclear complexes reached 6.9 and 7.3, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3317–3323, 2006     

Photolyse von ternären Fe(III)-Komplexen mit Oxalat- und Phenolat-Liganden

Photolysis of Ternary Fe(III)-Complexes with Oxalate and Phenolate Ligands The overall iron(II) quantum yields of the photolysis of mixed ligand complexes [Fe(C₂O₄)_3−nL_n]³⁻ (L = salicylate, sulfosalicylate or the dianion of catechol, sodium 3,5-sulfocatechol, tetrachlorcatechol) in aqueous solution within the spectral region 436 nm ≤ ^λ_irr. ≤ 546 nm are much smaller than those of the complexes [Fe(C₂O₄)_3−n(H₂O)_2n]³⁻²ⁿ (n = 0; 1; 2). This means that the intramolecular photoredoxreaction between iron(III) and the oxalate ligand is not sensitized by the L→Fe(III) charge transfer excitation. Moreover, filter effects through photoinactive complexes [FeL₂(H₂O)₂]⁻ or [FeL(H₂O)₄]⁺ probably give rise to the strong decrease of the quantum yields.     

Influence of Electrostatic Interactions on Complexes with Short O···O Hydrogen Bonds in Basic Salts of Pyridine Betaines and Acid Salts of ω-Phenyloalkanocarboxylic Acids

The isostructural complexes [C₅H₅N⁺(CH₂)_nCOO]₂HX and [C₆H₅(CH₂)_nCOO]₂HK (n = 1–4), which differ in their counterions and charge on the ring, were synthesized, and their powder FT-IR spectra analyzed. All complexes containing a charged pyridine ring are of Hadži type iii, characterized by an intense broad (continuum) absorption below 1600 cm⁻¹ typical of a short-strong hydrogen bond (SSHB) with a delocalized proton and a single vC=O band. The positively charged nitrogen atoms interact electrostatically with the X⁻ ion and, additionally, with one of the oxygen atoms of the carboxylic group, producing a more or less symmetric environment of the H-bonded proton, and stabilizing the SSHB. The broad absorption of [C₆H₅CH₂COO]₂HK is very similar to that of other pyridine complexes. Upon addition of methylene groups the broad absorption moves to higher wavenumbers, the O···O distance is elongated, and the H-bonded proton becomes more localized. In the spectrum of [C₆H₅(CH₂)₄COO]₂HK the vC=O and v_asCOO bands were found at 1704 and 1641 cm⁻¹, respectively, which shows that the H-bonded proton is asymmetrically located. The observed variation of absorption with the number of CH₂ groups reflects changes of contacts between the K⁺ ion and COO⁻ groups.     

Silyl group mediated linkage of closo-C2B10-cage to nido-C2B4-carborane: synthesis of the novel carborane ligand, 1-R-2-[5′-(SiMe2CH2)-2′,3′-(SiMe3)2-2′,3′-C2B4H5]-1,2-C2B10H10 (R=Me,Ph)

The reaction of the sodium salt of the monoanion, nido-[2,3-(Si(CH₃)₃)₂-2,3-C₂B₄H₅]⁻, with (chloromethyl)dimethylchlorosilane in a 1:1 molar ratio produced the B_(cage)-substituted cluster, nido-5-ClCH₂Si(CH₃)₂-2,3-(Si(CH₃)₃)₂-2,3-C₂B₄H₅ (1), in 81% yield. This product (1) was reacted further with the lithium salt of [closo-1-R-1,2-C₂B₁₀H₁₀]⁻ monoanion (R=Me, Ph) to give the novel linked and mixed C₂B₄/C₂B₁₀ carborane species, 1-Me-2-[5^′-SiMe₂CH₂-2^′,3^′-(SiMe₃)₂-2^′,3^′-C₂B₄H₅]-1,2-C₂B₁₀H₁₀ (2), 1-Ph-2-[5^′-SiMe₂CH₂-2^′,3^′-(SiMe₃)₂-2^′,3^′-C₂B₄H₅]-1,2-C₂B₁₀H₁₀ (3), in yields of 76% and 81%, respectively.     

Metallkomplexe mit biologisch wichtigen Liganden. CXXIII. Darstellung von Isophthaloyl‐ und Terephthaloyl‐di‐[(β,γ,δ)‐amino‐α‐aminocarboxylat]‐verbrückten zweikernigen Ruthenium‐, Rhodium‐ und Iridium‐Halbsandwich‐Komplexen

The reaction of the Cu(II) bis N,O‐chelate‐complexes of L‐2,4‐diaminobutyric acid, L‐ornithine and L‐lysine {Cu[H₂N–CH(COO)(CH₂)_nNH₃]₂}²⁺(Cl^–)₂ (n = 2–4) with terephthaloyl dichloride or isophthaloyl dichloride gives the polymeric complexes {‐OC–C₆H₄–CO–NH–(CH₂)_n–CH(nh₂)(COO)Cu(OOC)(NH₂)CH–CH₂)_n–NH‐}_x 1 – 5 . From these the metal can be removed by precipitation of Cu(II) with H₂S. The liberated ω,ω′‐N,N′‐diterephthaloyl (or iso‐phthaloyl)‐diaminoacids 6 – 10 react with [Ru(cymene)Cl₂]₂, [Ru(C₆Me₆)Cl₂]₂, [Cp*RhCl₂]₂ or [Cp*IrCl₂]₂ to the ligand bridged bis‐amino acidate complexes [L_n(Cl)M–(OOC)(NH₂)CH–(CH₂)_nNH–CO]₂–C₆H₄ 11 – 14 .     

Hydrogen Atom Attack on Fluorotoluenes: Rates of Fluorine Displacement

Rates of hydrogen atom attack on o-fluorotoluene (o-FTOL) and m-fluorotoluene (m-FTOL) at temperatures of 988–1144 K and pressures of 2–2.5 bar have been determined in a single-pulse shock tube study. Hydrogen atoms, generated from the decomposition of hexamethylethane, were allowed to react with the substrates and the characteristic products observed. Rate constants for two reaction channels, displacement of fluorine or methyl, were determined relative to displacement of methyl from 1, 3,5-trimethylbenzene (135TMB). Evidence is presented that abstraction of F is unimportant over the studied temperature range. With k(H + 135TMB → m-xylene + CH₃) = 6.7 × 10¹³ exp(–3255/T) cm³ mol⁻¹s⁻¹, the following rate expressions have been derived: k(H + o-FTOL → C₆H₅CH₃ + F) = 8.38 × 10¹³ exp(–6041/T) cm³ mol⁻¹s⁻¹; (1012–1142 K) k(H + o-FTOL → C₆H₅F + CH₃) = 2.37 × 10¹³ exp(–2938/T) cm³ mol⁻¹s⁻¹; (988–1142 K) k(H + m-FTOL → C₆H₅CH₃ + F) = 1.33 × 10¹⁴ exp(–6810/T) cm³ mol⁻¹s⁻¹; (1046–1144 K) k(H + m-FTOL → C₆H₅F + CH3) = 2.04 × 10¹³ exp(–3104/T) cm³ mol⁻¹s⁻¹; (1008–1144 K) Uncertainties in the relative rate constants are estimated to be factors of about 1.1, while the above absolute values have estimated expanded uncertainties of about a factor of 1.4 in rate, 10 kJ mol⁻¹ in the activation energy, and a factor of 3 in the A-factor. The present data are compared with relevant literature data. From our data and the thermochemistry, a model of the elementary steps comprising displacement of F is developed. On the basis of the model fit to our data, rate constants for the addition of atomic fluorine to toluene at 1100 K are derived. Rate expressions for fluorination reactions of toluene are also determined. The significance of the present results is discussed in the context of the formation of fluorinated byproducts in high-temperature systems.     

The Surface Chemistry of 1-Iodopropane Adsorbed on Pt(111)

On Pt(111) at 110 K, 1-iodopropane, C₃H₇I, adsorbs molecularly, but for doses below 1.7 × 10¹⁴ molecules cm⁻², only H₂ and I appear in thermal desorption. C–I bond cleavage occurs between 160 and 220 K, forming adsorbed n-propyl, C_(a)H₂CH₂CH₃, and atomic iodine, based on temperature-programmed desorption (TPD), high-resolution electron energy loss spectroscopy (HREELS), and X-ray photoelectron spectroscopy (XPS). n-Propyl undergoes β-hydride elimination forming propylene, with desorption peaks at 185 and 240 K. At 240 K, hydrogenation to propane also occurs. Some di-σ bonded propylene, C_(a)H₂C_(a)HCH₃, remains at 240 K and it rearranges to propylidyne near 300 K. Atomic H, bound to Pt, recombines and desorbs at ca. 260 K. Further desorption of H₂ is limited by C–H bond breaking and occurs over a broad temperature range with local maxima at ca. 280, 320, and 420 K, typical of propylidyne fragments on Pt. Atomic iodine desorbs in a broad feature at 825 K.     

Substituierte Alkinyle als axiale Liganden an häminähnlich gebundenem Eisen(III) - Einordnung in eine spektrochemische Serie

Substituted Alkinyles as Axial Ligands at Hemine Like Bound Iron(III) - Incorporation into a Spectrochemical Series . Substituted lithium alkynyles Li CC R (R = ^tBu, Ph, p-Cl C₆H₄, Me₃Si, ⁱPr₃Si, Ph₃Si) react with the hemine like macrocyclic iron(III) complex 6,13-di(ethoxycarbonyl)-5, 14-dimethyl-1, 4, 8, 11-tetraazatetradeca-4,6,12,14-tetraenato[2⁻]iron(III)-iodide (formula 2 ;) in tetrahydrofuran to form anionic low-spin di-adducts [fe(CC R)₂]⁻. The incorporation of the alkynyles into a spectrochemical series of the axial ligands (studied by the sharp equatorial-ligand-to-metal CT absorption band) results in the wavelength-sequence (nm): OH⁻ (≈︁ 510) « N₃⁻ (≈︁ 625) < ^tBu CC⁻ (664) < NH₃ (666) < Ph CC⁻ (692) < Ph NH₂ (695) < Me₃Si CC⁻ (698) < SCN⁻ (713) < Ph₃Si C  C⁻ (716) < CN⁻ (739) < 4-picoline (759) < pyridine (765) < nicotinamide (776) < methylnicotinat (788) < pyrazine (798) and points to a significant π-acceptor ability of the silyl substituents.     

A bipolar electrospray source of singly charged salt clusters of precisely controlled composition

The few clusters [B^?_nA⁺_n+1]⁺ (n = 0,1) with resolvable mobilities formed in electrosprays of large salts have been used for nanoparticle instrument testing and calibration at sizes smaller than 2 nm. Extensions of this modest size range by charge reduction with uncontrolled gas phase ions has resulted in impure singly charged clusters. Here, we combine two oppositely charged electrosprays of solutions of the same salt B^?A⁺, including: (C_nH_2n+1)₄N⁺Br^? (n = 4,7,12,16), the large phosphonium cation (C₆H₁₃)₃(C₁₆H₃₃)P⁺ paired with the anions Im^? [(CF₃SO₂)₂N^?] or FAP^? [(C₂F₅)₃PF₃^?], and the asymmetric pair [1-methyl-3-pentylimidazolium⁺FAP^?]. Both polarities are simultaneously produced by this source in comparable abundances, primarily as singly charged A⁺_nB^?_n±1, with tiny contributions from higher charge states. Some but not all of these clusters produce narrow mobility peaks typical of pure ions, even beyond n = 43. Excellent independent stable control of the positive and the negative sprays brought very close to each other is achieved by isolating them electrostatically with a symmetrically interposed metallic screen. Two nanoDMAs covering the size range up to 30 nm (Halfmini and Herrmann DMAs, with classification lengths of 2 and 10 cm) are characterized with these standards, revealing resolving powers considerably higher than previously seen with unipolar electrospray sources. The bipolar source of pure and chemically homogeneous clusters described permits studying size and charge effects in a variety of aerosol instruments in the 1–4 nm size range.

Copyright © 2017 American Association for Aerosol Research     

Polymerized Surfactant Vesicles

Irradiation of surfactant vesicles prepared from (C₁₈H₃₇)₂ N⁺(CH₃)C₆H₄-CHCH₂p,CT⁻, 1, [C₁₅H₃₁CO₂(CH₂)₂]₂N⁺(CH₃)CH₂C₆H₄CHCH₂,CL⁻ 2, and (C₁₈-H₃₇)₂N⁺(CH₃)CH₂CH₂OCOC₆H₄CHCH₂p,Br⁻, 3, by ultraviolet light or by bursts of 266 nm laser pulses have resulted in the loss of styrene absorbances. This process has been accounted for in terms of a model which considers intravesicular surface reactions to give polymers with average chainlength of 22. Degreees of photopolymerization have been determined in vesicles prepared from 3 subsequent to separating the polystryrene, formed in the photolysis, from the surfactants. Vesicle surface photopolymerizations result in aqueous cleft formation and in enhanced stabilities. Polymerized vesicles provide media for in situ generation of colloidal catalysts and semiconductors.     

Hexachloroplatinate(IV) anion-induced cucurbit[5]uril and cucurbit[8]uril supramolecular assemblies with linear channels

Two Q[n]-based porous compounds, Q[5]·[PtCl₆]^2 −·2H₃O·12H₂O and 2Q[8]·[PtCl₆]^2 −·2H₃O·74H₂O in cooperating the hexachloroplatinate(IV) anion ([PtCl₆]^2 −) as an inorganic structure directing agent are demonstrated. The driving forces for the formation of such novel Q[n]-based porous compounds are considered to be the outer surface interactions of Q[n]s, including dipole interactions between Q[n]s and ion-dipole interactions between [PtCl₆]^2 − anions and Q[n]s. Moreover, the Q[5]-based porous compound displays absorption distinctness for tetrachloromethane, whereas the Q[8]-based porous compound displays absorption distinctness for methanol.     

Ionic liquid-based extraction and separation trends of bioactive compounds from plant biomass

Ionic liquids have been projected as the best solvent for extraction and separation of bioactive compounds from various origins. This review offers a collection of the published results, using ionic liquids for the extraction and purification of biomolecules. Ionic liquids have been studied as solvents, co-solvents and supported materials for separation of bioactive compounds. The ionic liquids-based extraction procedures were previously reported, such as ionic liquids-based solid-liquid extraction, liquid-liquid extraction and ionic liquids-modified materials are reviewed and compared to their performance. In this review, the main activities and future challenges are discussed, with major gaps identified using ionic liquids in extraction procedures and by advancing few steps to overcome these drawbacks.

Abbreviation: [(HSO₃)C₄MIM]⁺: 1-(4-sulfonylbutyl)-3-methylimidazolium; [(C₆H₃OCH₂)₂im]⁺: 1,3-dihexyloxymethylimidazolium; [C_nC₁MIM]⁺: 1-alkyl-2,3-dimethylimidazolium; [C_nMIM]^{+; [Cn, 2, 3, 4, 6, 8, 10, 12]}: 1-alkyl-3-methylimidazolium; [C_nC₁pyr]⁺: 1-alkyl-3-methylpyridinium; [C_nim]⁺: 1-alkylimidazolium; [C_npyr]⁺: 1-alkylpyridinium; [aC_nim]⁺: 1-allyl-3-alkylimidazolium; [C₇H₇MIM]⁺: 1-benzyl-3-methylimidazolium; [C₄(C₁C₁C₁Si)im]⁺: 1-butyl-3-trimethylsilylimidazolium; [(HOOC)C₂MIM]⁺: 1-carboxyethyl-3-methylimidazolium; [(OH)C_nMIM]⁺: 1-hydroxyalkyl-3-methylimidazolium; [(C₂H₅O)₃SiC₃MIM]⁺: 1-methyl-3-(triethoxy)silypropyl imidazolium; [(NH₂)C₃MIM]⁺: 1-propylamine-3-methylimidazolium; [C_wH_xN_yO_z]⁺: Chirally functionalized methylimidazolium; [P_{10(3OH)(3OH)(3OH)}]⁺: Decyltris(3-hydrox- ypropyl) phosphonium; [N_111(2OH)]⁺: N,N,N-trimethyl-N-(2-hydroxyethyl) ammonium (cholinium); [N_00nn]⁺: N,N-dialkylammonium; [N_0nn(2OH)]⁺: N,N-dialkyl-N-(2-hydroxyethyl) ammonium; [C₁₀C₁₀C₁gluc]⁺: N,N-didecyl-N-methyl-d-glucaminium; [N_11(2(O)1)0]⁺: N,N-dimethyl(2-methoxyethyl) ammonium; [N_{11(2OH)(C7H7)}]⁺: N-benzyl-N,N-dimethyl-N-(2-hydroxyethyl) ammonium; [P₆₆₆₁₄]⁺: Trihexyltetradecylph- osphonium; [P_i(444)1]⁺: Triisobutyl (methyl) phosphonium; P.minus: Polygonum minus; NPs: Nanoparticle; ZnO : Zinc oxide nanoparticles ; Ni NPs: Nickel nanoparticles; MO: Methyl orange; UAE: Ultrasonic-assisted extraction; LLE: Liquid-liquid extraction; ABS: Aqueous biphasic system ; [Ace]^?: Acesulfamate; [Ala]^?: alalinate; [TMPP]^?: bis(2,4,4-trimethylpentyl)phosphinate; : ; [NTf₂]^?: bis(trifluoromethylsulfonyl)imide; [[Br]^–]: [Br]omide; [Calc]: calkanoate; [Cl]^–: chloride; [Bz]^?: benzoate; [PF₆]^?: hexafluorophosphate; [HSO₄]^?: hydrogenosulfate; [OH]^?: hydroxide; I^–: iodide; [Lac]^?: lactate; [NO₃]^?: nitrate; [[Cl]O₄]^?: perchlorate; [Phe]^?: phenilalaninate; [BF₄]^?: tetrafluoroborate; [SCN]^?: thiocyanate; [C(CN)₃]^?: tricyanomethanide; [CF₃CO₂]^?: trifluoroacetate; [CF₃SO₃]^?: trifluoromethanesulfonate; [FAP]^?: tris(pentafluoroethyl)trifluorophosphate; ILs: Ionic liquids; Ag NPs: Silver nanoparticle; Cu NPs: Copper nanoparticle; MB: Methylene blue; MR: Methyl red ; MAE: Microwave-assisted extraction; SLE: solid-liquid extraction.