Synthesis of phosphate-type fluorocarbon-hydrocarbon hybrid surfactants and their adsorption onto calcium hydroxyapatite

Five novel phosphate-type hybrid surfactants, C_mF_2m+1C₆H₄CH[OPO₂(OC₆H₅)Na]C_nH_2n+1 (FmPHnPPhNa: m = 4, 6, 8; n = 3, 5; C₆H₄ = p-phenylene, C₆H₅ = phenyl), have been synthesized. When compared with sulfate-type hybrid surfactants, C_mF_2m+1C₆H₄CH(OSO₃Na)C_nH_2n+1 (C₆H₄ = p-phenylene), the new hybrid surfactants are found to have comparable abilities to lower surface tension of water. The critical micelle concentrations of FmPHnPPhNa follow Klevens rule and their occupied areas per molecule increase with increasing m and n. Calcium hydroxyapatite (CaHAp) pellets modified with FmPH3PPhNa gives high hydrophobic and lipophobic surfaces. The hybrid surfactants are expected as new dental reagents for oral hygiene.     

Synthesis and solution properties of sulfate-type hybrid surfactants with a benzene ring

Nine novel sulfate-type hybrid surfactants, C_mF_2m+1C₆H₄CH(OSO₃Na)C_nH_2n+1 (FmPHnOS: m=4, 6, 8; n=3, 5, 7; C₆H₄: p-phenylene), with a benzene ring in their molecules were synthesized. Alkanoyl chlorides were allowed to react with iodobenzene in the presence of aluminum chloride to give the corresponding aromatic ketones. The reaction of the ketones with perfluoroalkyl iodides yielded 1-[4-(perfluoroalkyl)phenyl]-1-alkanones as intermediates. The intermediates were allowed to react with methanol in tetrahydrofuran in the presence of sodium borohydride to yield 1-[4-(perfluoroalkyl)phenyl]-1-alkanols. The desired hybrid surfactants were obtained by the reaction of 1-[4-(perfluoroalkyl)phenyl-1-alkanols with sulfur trioxide/pyridine complex in pyridine and by the subsequent neutralization of the products with sodium hydroxide solution. When compared with the conventional hybrid surfactants, C_mF_2m+1C₆H₄COCH(SO₃Na)C_nH_2n+1 (FmHnS: m=4, 6; n=2, 4, 6; C₆H₄: p-phenylene), the new hybrid surfactants thus synthesized were found to have a comparable ability to lower the surface tension of water and a high hydrophilicity. The cmc of FmPHnOS obeyed Kleven’s rule and their occupied areas per molecule increased with increasing m and n with the values between 0.66 and 1.05 nm². The aggregation number for FmPHnOS micelles ranged from 6 to 45 and the hydrodynamic radius of the micelles was in the range of 1.4-3.1 nm.     

Synthesis and properties of gemini-type hydrocarbon-fluorocarbon hybrid surfactants

Gemini-type hybrid surfactants with two fluorocarbon chains connected through a hydrocarbon spacer, F(CF₂)_m(CH₂)₂CH(OSO₃Na)(CH₂)_nCH(OSO₃Na)(CH₂)₂(CF₂)_mF [Fm(Hn)FmOS, m = 4, 6; n = 5, 6, 7, 8)], were synthesized and their surface chemical properties were examined with the aim to have highly functional and highly water-soluble fluorinated surfactants when compared with the conventional fluorinated surfactants. Comparisons of the surface chemical properties of the synthesized gemini-type hybrid surfactants with those of monounit-type hybrid surfactants, F(CF₂)_m(CH₂)₂CH(OSO₃Na)(CH₂)_nH [FmEHnOS, m = 4, 6; n = 3, 5)], revealed that gemination causes a remarkable lowering (about 1/100) in cmc value while it produces little changes in Krafft point (below 0 °C) and surface tension at cmc (γ_cmc).     

Synthesis and surface activities of organic solvent-soluble fluorinated surfactants

A variety of fluorinated surfactants soluble in organic solvent were prepared, including C₈F₁₇SO₂NHC_nH_2n+1 (n = 2, 4, 6, 8, 10), C₈F₁₇SO₂NHR (R = C₆H₁₁, C₆H₅), C₈F₁₇SO₂N(C_nH_2n+1)₂ (n = 1, 2, 3, 4) and C₈F₁₇SO₂NH(CH₂)_nNHO₂SC₈F₁₇ (n = 6, 10). Their surface activities in various organic solvents were determined by surface tension measurement. The results showed that these fluorinated surfactants can reduce the surface tension of both polar and non-polar organic solvents. In general, organic solvents with strong polarity or long alkyl chain are beneficial to increase the surface activity of these polar fluorinated surfactants. By comparing fluorinated surfactants with the same fluorocarbon segment and connecting group, C₈F₁₇SO₂N(C_nH_2n+1)₂ (n = 1, 2, 3, 4) showed lower surface activity in organic solvents than C₈F₁₇SO₂NHC_nH_2n+1 (n = 2, 4, 6, 8) with an equal carbon number of the solvophilic group. Through surface tension vs. concentration curves given for N-octyl perfluorooctanesulfonamide in various organic solvents, a break point like the critical micelle concentration of ordinary surfactants in aqueous solutions was observed, and the effect of the different types of organic solvents on adsorption and aggregation behavior was also studied.     

Striking differences between alkyl sulfate and alkyl sulfonate when mixed with cationic surfactants

The properties of alkyl sulfate and alkyl sulfonate are similar except for their Krafft points. However, alkyl sulfate and alkyl sulfonate behave quite differently when they are mixed with cationic surfactants and show some totally unexpected results. In this work sodium alkyl sulfate (C_nH_2n+1SO₄Na,C_nSO₄)–alkyl quaternary ammonium bromide [C_nH_2n+1N(C_mH_2m+1)₃Br, C_nN, m=1–4] mixtures and sodium alkyl sulfonate (C_nH_2n+1SO₃Na, C_nSO₃)–C_nN mixtures were studied. It was found that, in contrast to the single surfactants, C_nSO₃–C_nN mixtures were much more soluble than C_nSO₄–C_nN mixtures. Besides, the two kinds of catanionic surfactant mixtures were quite different in their phase behavior and aggregate properties. The results were interpreted in terms of the interactions between surfactant molecules, which were very different in the two kinds of mixed systems owing to the distinction between alkyl sulfate and alkyl sulfonate in the molecular charge distribution.     

ESR Studies on the Micellization Behaviors of a Series of Novel Asymmetric Gemini Surfactants

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Synthesis and properties of triethylalkylammonium perfluorooctanesulfonates (APFOS)

Six ionic surfactants containing a perfluorooctanesulfonic anion and a positively charged ammonium in a molecule, R_FSO₃⁻N⁺Et₃C_nH_2n+1 (n=2, 4, 6, 8, 10 and 12), were prepared from perfluorooctanesulfonyl fluoride, triethylamine and linear alkanol. Solution properties of triethylalkylammonium perfluorooctanesulfonates (APFOS) have been measured in terms of surface tension. The values of critical micelle concentration (cmc) decrease with an increase of N-alkyl chain length, and the logarithm of the cmc decreases linearly with increasing N-alkyl chain length (n≥6), while the negative values of standard free energy for the adsorption become larger as the N-alkyl chain length increases.     

Synthesis and coordination chemistry of fluorinated phosphonic acids

Phosphonic acids [(HO)₂P(O)C₂H₄C_nF_2n+1] (n = 4, 6) and [(HO)₂P(O)C₆H₄-4-C_nF_2n+1] (n = 0, 1, 6) have been prepared in good yields. Deprotonation and reaction with cis-[PtCl₂(PPh₃)₂] affords fluorinated platinum complexes which have been characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Pt{O₂P(O)C₆H₄-4-F}(PPh₃)₂], [Pt{O₂P(O)C₆H₄-4-CF₃}(PPh₃)₂] and [Pt{O₂P(O)C₂H₄C₆F₁₃}(PPh₃)₂] have been determined by single crystal X-ray diffraction.     

Muttiphoton Ionization of Benzene-Ammonia Clusters: Intracluster Reaction and Cluster Ion Stability

Neutral benzene-ammonia clusters, prepared in a supersonic expansion, were ionized using multiphoton ionization. The cluster ions were investigated with a time-of-flight mass spectrometer. The observed major cluster ions, under 355-nm laser irradiation, resulting from prompt intracluster ion-molecule reaction and fragmentation following ionization are (C₆H₆)_m(NH₃)_nH⁺, m = 1–6, n = 1–4 and (C₆H₆)_m⁺, m = 1–3. The results of isotopic labeling experiments clearly indicate that C₆H₆ does not participate in intracluster ion-molecule reactions to form (C₆H₆)_m(NH₃)_nH⁺. A local maximum appears at n = 2 in the intensity distribution of (C₆H₆)_m(NH₃) _nH⁺ for each value of m under all experimental conditions. This finding indicates that (C₆H₆)_m(NH₃)₂H⁺ is more stable than any other (C₆H₅)_m(NH₃)_mH⁺ (n = 1,3,4) for m = 1–6.     

Synthesis of triphilic, Y-shaped molecular surfactants

Novel multiphilic molecules comprising three chains with antagonistic affinities have been synthesized. These ‘triphilic’ surfactants (FnHmEOy) contain a perfluorinated arm (Fn=C_nF_2n+1), a hydrocarbon arm (Hm=C_mH_2m+1), and a methyl-caped, poly(ethylene glycol) arm (EOy=CH₃(OC₂H₄)_yO). These moieties have variable lengths (n=5 or 7, m=8, 10, or 14, and y=2-7) and are interconnected in a Y shape; hence, each unit is directly connected to the other two. The key intermediates in the synthetic route are 3-F-alkyl-3-alkyloxypropanoic acids, on which the polar EOy chain is subsequently grafted. Monodisperse methyl-caped diethylene glycol (EO2) and triethylene glycol (EO3) led to the corresponding monodisperse triaffine surfactants. In parallel, a library of five F5H10EOy triaffines (y=3-7) has been obtained simultaneously when starting from the polydisperse methyl-caped poly(ethylene glycol) MPEG 350. Separation of pure individual compounds was achieved through column chromatography on silica gel. The relative concentration of the Z and E isomers has been quantified in the reaction mixtures of the intermediates and final products by ¹H NMR (Z largely predominant). Several products have been obtained in their isomerically pure form. Chemical characterization (¹H, ¹³C, and ¹⁹F NMR, elemental analysis) was consistent with the expected structures.     

Etude RMN du 13C de composes fluoroaliphatiques et de tensioactifs non ioniques perfluoroalkyles

Carbon-13 chemical shifts, spin-lattice relaxation times and nuclear Overhauser enhancement factors at 28°C are reported for a series of polyfluoroaliphatic compounds :

, and perfluoroalkyl nonionic surfactants C_mF_2m+1CH₂(OC₂H₄)_nOH with m = 6, 7 and n = 3, 4, 5, 6 and C₆F₁₃CH₂CH₂CONH(C₂H₄O)_nH with n = 3, 4. The influence of the perfluoroalkyl group on the ¹³C chemtcal shifts of the neighbouring hydrogenated carbons is discussed in terms of hyperconjugative type interactions between lone electron pairs on fluorine and the neighbouring CC or CO bond. Relaxation data show similar flexibilities of the fluorinated chains in the different molecules investigated. Nonionic surfactants exhibit segmental motions in both the hydrophobic perfluoroalkyl and the hydrophilic polyoxyethylene chains ; these motions appear to be similar to those of the analogous hydrogenated surfactants.     

Gas phase ion/molecule reactions in phosphine/germane mixtures studied by ion trapping

Gaseous mixtures of phosphine and germane have been investigated by ion trap mass spectrometry. Reaction pathways together with rate constants of the main reactions are reported. The mechanisms of ion/molecule reactions have been elucidated by single and multiple isolation steps. The GeH_n⁺ (n = 1–3) ions react with phosphine to give GePH_n⁺ (n = 2–4) ions. The GePH₄⁺ ion further reacts with GeH₄ to yield Ge₂PH₆⁺. The GePH_n⁺ (n = 2–4) mixed ionic family also originates from the P⁺ phosphine primary ion, as well as from the P₂H_n⁺ (n = 0–3) secondary ions of phosphine reacting with neutral germane and from Ge₂H₂⁺ reacting with phosphine. The main reaction pathways of the PH_n⁺ (n = 0–2) ions with GeH₄ lead to the formation of the GeH₂⁺ and GeH₃⁺ ionic species. Protonation of phosphine from different ionic precursors is a very common process and yields the stable phosphonium ion, PH₄⁺. Trends in total abundances of secondary GePH_n⁺ (n = 2–4) ions as function of reaction time for different PH₃/GeH₄ pressure ratios show that excess of germane slightly affects the nucleation of mixed Ge-P ions.     

Synthesis and coordination chemistry of perfluoroalkylated dithiophosphate ligands

Dithiophosphoric acids [HS₂P(OC₂H₄C_nF_2n+1)₂] (n = 4, 6) have been prepared in high yields. Deprotonation and reaction with transition metal substrates affords fluorous metal complexes which have been characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Cu{S₂P(OC₂H₄C_nF_2n+1)₂}(PPh₃)₂] (n = 4, 6) and [Cu{-S₂P(OC₂H₄C₄F₉)₂}(PPh₃)]₂ have been determined by single crystal X-ray diffraction.     

Synthesis of molecular chains: phenylene thioether and sulfoxide oligomers

The application of a general synthetic approach to prepare molecular chains is reported. It is based on a step-by-step method each consisting first in a Pd-catalyzed reaction between ArI and HXAr′Br (Ar=aryl, Ar′=arylene) to give ArXAr′Br followed by a Cu-catalyzed replacement of Br by I to give ArXAr′I that can be reacted with HXAr′Br in the following step. The application of this method is here illustrated to prepare phenylene sulfide oligomers (X=S). Starting from RC₆H₄I-4 (R=H, MeO, NO₂, NH₂) and HSC₆H₄Br-x (x=2, 4) it is possible to grow chains in one direction to give X(C₆H₄S-m)_nC₆H₄R-4 (n=1, X=Br, m=4, R=H, MeO, NO₂, NH₂, SMe and m=2, R=H, MeO, NO₂; n=1, X=I, m=2 or 4, R=H, MeO, NO₂; n=2, X=Br, m=2 or 4, R=H, MeO, NO₂; n=2, X=I, m=4, R=MeO, NO₂; n=3, X=Br, m=4, R=MeO, NO₂; n=3, X=I, m=4, R=NO₂ and n=4, X=Br or I, m=4, R=NO₂). From HSC₆H₄Br-x and IC₆H₄I-4 the chains can grow in two directions to give X(C₆H₄S-4)_nC₆H₄X-4 (n=2 or 4, X=Br or I), 2-XC₆H₄(SC₆H₄-4)_nSC₆H₄X-2 (n=3 or 5, X=Br). Using diiodomesitylene the dithioethers C₆HMe₃-2,4,6-(SC₆H₄X-4)₂-1,3 (X=Br, I) have been prepared. The series of sulfoxides X(C₆H₄S(O)-4)_nC₆H₄R-4 (X=Br, n=1, R=MeO, n=3, R=NO₂, n=4, R=Br; X=R=I, n=2) has been obtained from the corresponding thioethers and PhICl₂.     

New types of asymmetrical bromonium salts [RF(RF′)Br]Y where RF and/or RF′ represent perfluorinated aryl, alkenyl, and alkynyl groups

A series of previously unknown asymmetrical fluorinated bis(aryl)bromonium, alkenyl(aryl)bromonium, and alkynyl(aryl)bromonium salts was prepared by reactions of C₆F₅BrF₂ or 4-CF₃C₆H₄BrF₂ with aryl group transfer reagents Ar′SiF₃ (Ar′ = C₆F₅, 4-FC₆H₄, C₆H₅) or perfluoroorganyl group transfer reagents R_F′BF₂ (R_F = C₆F₅, trans-CF₃CFCF, C₃F₇C≡C) preferentially in weakly coordinating solvents (CCl₃F, CCl₂FCClF₂, CH₂Cl₂, CF₃CH₂CHF₂ (PFP), CF₃CH₂CF₂CH₃ (PFB)). The presence of the base MeCN and the influence of the adducts R_F′BF₂·NCMe (R_F = C₆F₅, CF₃C≡C) on reactions aside to bromonium salt formation are discussed. Reactions of C₆F₅BrF₂ with Alk_F′BF₂ in PFP gave mainly C₆F₅Br and Alk_F′F (Alk_F′ = C₆F₁₃, C₆F₁₃CH₂CH₂), presumably, deriving from the unstable salts [C₆F₅(Alk_F′)Br]Y (Y = [Alk_F′BF₃]⁻). Prototypical reactivities of selected bromonium salts were investigated with the nucleophile I^-and the electrophile H⁺. [4-CF₃C₆H₄(C₆F₅)Br][BF₄] showed the conversion into 4-CF₃C₆H₄Br and C₆F₅I when reacted with [Bu₄N]I in MeCN. Perfluoroalkynylbromonium salts [C_nF_2n+1C≡C(R_F)Br][BF₄] slowly added HF when dissolved in aHF and formed [Z-C_nF_2n+1CFCH(R_F)Br][BF₄].     

Characterization of isomeric [CH5P]+˙ and [C2H7P]+˙ radical cations and some [C2H6P]+ phosphonium ions in the gas phase by their collisional activation spectra

Collisional activation spectra were used to characterize isomeric ion structures for [CH₅P]^+˙ and [C₂H₇P]^+˙ radical cations and [C₂H₆P]⁺ even-electron ions. Apart from ionized methylphosphane, [CH₃PH₂]^+˙, ions of structure [CH₂PH₃]^+˙ appear to be stable in the gas phase. Among the isomeric [C₂H₇P]^+˙ ions stable ion structures [CH₂PH₂CH₃]^+˙ and [CH₂CH₂PH₃]^+˙/[CH₃CHPH₃]^+˙ are proposed as being generated by appropriate dissociative ionization reactions of alkyl phosphanes. At least three isomeric [C₂H₆]⁺ ions appear to exist, of which \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} - \mathop {\rm P}\limits^{\rm + } {\rm H = CH}_{\rm 2} $\end{document} could be identified positively.     

N-aryl-and N-vinyldiaza-18-crown-6: Synthesis and complexing ability

The nucleophilic aromatic and vinyl substitution using diaza-18-crown-6 as nucleophile afforded a number of its N,N’-diaryl-[aryl = 2,4-(NO₂)₂C₆H₃, 4-C₅F₄N, 4-CF₃C₆F₄] and N,N’-dialkenyl-substituted derivatives [alkenyl = PhC(O)CH=CH, MeOCOCH=CH, (EtO₂C)₂C=C(Ph), etc.]. Arylation of diaza-18-crown-6 with nonactivated aryl bromides, such as 4-Me₂NC₆H₄Br, 4-MeOC₆H₄Br, C₆H₅Br, and 4-CF₃C₆H₄Br, was effected under catalysis by palladium complexes. N,N’-Diaryldiaza-18-crowns-6 having electron-acceptor substituents in the aromatic rings turned out to be incapable of forming complexes with metal cations, while their analogs containing electron-donor para-methoxy and para-dimethylamino groups gave complexes with barium perchlorate.     

Reactions of some fluoroaromatics with the ethoxide anion

The reactions of sodium ethoxide in ethanol with various fluoroaromatics, C₆F_6?nH_n, C₆F_5?nH_nNO₂, C₆F₅X (X = CF₃, C₆F₅, COCH₃, CH₂Br), C₆Cl₆ and $\text{m}$H₂C₆Cl₄ have been studied. Partial substitution of the aromatic halogen was observed. The new products have been characterized by elemental analysis, NMR (H?1 and F?19), infrared and mass spectroscopy.     

Fastener effect on magnetic properties of chain compounds of dinuclear ruthenium carboxylates

Chlorido-bridged chain complexes of dinuclear ruthenium benzoate analogues, [Ru₂{3,4,5-(C _m H_2m+1O)₃C₆H₂CO₂}₄Cl] _n (mCl) (m = 3, 5–7, 9, 11, 13, 15, 17), were synthesised and the crystal structure of 3Cl · 2nH₂O was revealed. The magnetic measurements for a series of the complexes mCl (m = 2–18) revealed that all the complexes show an antiferromagnetic interaction between the dinuclear unit, with a fastener effect giving the stronger interaction as the alkyl-chain length m increases.