Synthesis and characterization of ionic liquids containing copper, manganese, or zinc coordination cations

Copper-, manganese-, and zinc-based ionic liquids (Cu{NH(2)CH(2)CH(2)OH}(6)[CH(3)(CH(2))(3)CH(C(2)H(5))CO(2)](2) (2), Cu{NH(CH(2)CH(2)OH)(2)}(6)[CH(3)(CH(2))(3)CH(C(2)H(5))CO(2)](2) (3A), Cu{NH(CH(2)CH(2)OH)(2)}(6)[CF(3)SO(3)](2) (3B), Cu{NH(CH(2)CH(2)OH)(2)}(6)[(CF(3)SO(2))(2)N](2) (3C), Mn{NH(CH(2)CH(2)OH)(2)}(6)[CF(3)SO(3)](2) (4), and Zn{NH(2)CH(2)CH(2)OH}(6)[CF(3)SO(3)](2) (5)) are synthesized in a single-step reaction. Infrared data suggest that ethanolamine preferentially coordinates to the metal center through the amine group in 2 and the hydroxyl group in 5. In addition, diethanolamine coordinates through the amine group in 3A, 3C, and 4 and the hydroxyl group in 3B. The compounds are viscous (>1000 cP) at room temperature, but two (3C and 4) display specific conductivities that are reasonably high for ionic liquids (>20 mS cm(-1)). All of the compounds display a glass transition (T(g)) below -50 °C. The cyclic voltammograms (CVs) of 2, 3A, 3B, and 3C display a single quasi-reversible wave associated with Cu(II)/Cu(I) reduction and re-oxidation while 5 shows a wave attributed to Zn(II)/Zn(0) reduction and stripping (re-oxidation). Compound 4 is the first in this new family of transition metal-based ionic liquids (MetILs) to display reversible Mn(II)/Mn(III) oxidation and re-reduction at 50 mV s(-1) using a glassy carbon working electrode.     

Simple organofluorine compounds giving field-dependent 13C and 19F NMR spectra with complex patterns: higher order effects and cross-correlated relaxation

The CF(3) signals in the (13)C{(1)H} spectrum of 1,1,1,3,3,3-hexafluoroisopropyl alcohol and the (CF(3))(2) CH signals in the corresponding triflate exhibit much greater complexity than might first be expected. The same holds for the (13)C satellites in the (19)F spectra. Complex patterns appear because of higher order effects resulting from the combination of a relatively large four-bond (19)F-(19)F J coupling in the ((13)CF(3))(12)CH((12)CF(3))-containing isotopomer and a typical large one-bond (13)C/(12)C isotope effect on the (19)F chemical shift. This complexity cannot be eliminated at very high magnetic field strengths. The triflate (CF(3))(2)CH-O-SO(2)CF(3) presents still additional complexity because of the presence of two different types of CF(3) groups exhibiting (6)J(FF) in any of the isotopomers and the chemical shift differences in hertz between the various (19)F signals in the two different (13)CF(3)-containing isotopomers. In addition, the presence of a small (5)J(CF) in the ((13)CF(3))((12)CF(3))(12)CH-O-SO(2) (12)CF(3) isotopomer is revealed only through simulations. The hexafluoroisopropyl CF(3) groups in the alcohol and triflate and the SO(2)CF(3) group in the triflate apparently provide the first examples of cross-correlated relaxation in (13)CF(3) groups. An analysis of the spectra in the context of previously reported work highlights the novel aspects of our findings. In particular, for each part of the complex hexafluoroisopropyl CF(3) quartet, peak height and linewidth variations resulting from cross-correlated relaxation are observed. These variations within a group of (13)C signals reflect different spin-lattice and spin-spin relaxation rates for the transitions within that group arising from higher order coupling effects.     

Conformational analysis and assignments of relative stereocenter configurations in fluoroalkyl-iridium complexes using 19F[1H] HOESY experiments. Comparison with solid-state X-ray structural results

Solution conformations about the metal-carbon bond of the secondary fluoroalkyl ligands in iridium complexes [IrCp(PMe(3))(R(F))X] [Cp* = C(5)Me(5); R(F) = CF(CF(3))(2), X = I (1), CH(3) (2); R(F) = CF(CF(3))(CF(2)CF(3)), X = I (4), CH(3) (5)] have been determined using (19)F[(1)H] HOESY techniques. The molecules adopt the staggered conformation with the tertiary fluorine in the more hindered sector between the PMe(3) and X ligands, with CF(3) (and CF(2)CF(3)) substituents lying in the less hindered regions between PMe(3) and Cp or X and Cp. In molecules containing the CF(CF(3))(2) ligand, these conformations are identical to those adopted in the solid state. For compound 4, containing the CF(CF(3))(CF(2)CF(3)) ligand, two diastereomers are observed in solution. Solution conformations and relative stereocenter configuration assignments have been obtained using (19)F[(1)H] HOESY and correlated with the X-ray structure for the major diastereomer of 4, which has the (S(Ir), S(C)) or (R(Ir), R(C)) configuration. Relative stereocenter configurations of analogue 5, for which no suitable crystals could be obtained, were assigned using (19)F[(1)H] HOESY and proved to be different from 4, with 5 preferring the (S(Ir), R(C)) or (R(Ir), S(C)) configuration.     

Dehydration reaction of hydroxyl substituted alkenes and alkynes on the Ru(2)S(2) complex

A variety of inter- and intramolecular dehydration was found in the reactions of [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)(mu-S(2))](CF(3)SO(3))(4) (1) with hydroxyl substituted alkenes and alkynes. Treatment of 1 with allyl alcohol gave a C(3)S(2) five-membered ring complex, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(2)CH(2)CH(OCH(2)CH=CH(2))S]](CF(3)SO(3))(4) (2), via C-S bond formation after C-H bond activation and intermolecular dehydration. On the other hand, intramolecular dehydration was observed in the reaction of 1 with 3-buten-1-ol giving a C(4)S(2) six-membered ring complex, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2) [mu-SCH(2)CH=CHCH(2)S]](CF(3)SO(3))(4) (3). Complex 1 reacts with 2-propyn-1-ol or 2-butyn-1-ol to give homocoupling products, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCR=CHCH(OCH(2)C triple bond CR)S]](CF(3)SO(3))(4) (4: R = H, 5: R = CH(3)), via intermolecular dehydration. In the reaction with 2-propyn-1-ol, the intermediate complex having a hydroxyl group, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH=CHCH(OH)S]](CF(3)SO(3))(4) (6), was isolated, which further reacted with 2-propyn-1-ol and 2-butyn-1-ol to give 4 and a cross-coupling product, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH=CHCH(OCH(2)C triple bond CCH(3))S]](CF(3)SO(3))(4) (7), respectively. The reaction of 1 with diols, (HO)CHRC triple bond CCHR(OH), gave furyl complexes, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SSC=CROCR=CH]](CF(3)SO(3))(3) (8: R = H, 9: R = CH(3)) via intramolecular elimination of a H(2)O molecule and a H(+). Even though (HO)(H(3)C)(2)CC triple bond CC(CH(3))(2)(OH) does not have any propargylic C-H bond, it also reacts with 1 to give [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(2)C(=CH(2))C(=C=C(CH(3))(2))]S](CF(3)SO(3))(4) (10). In addition, the reaction of 1 with (CH(3)O)(H(3)C)(2)CC triple bond CC(CH(3))(2)(OCH(3)) gives [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(2)][mu-S=C(C(CH(3))(2)OCH(3))C=CC(CH(3))CH(2)S][Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)]](CF(3)SO(3))(4) (11), in which one molecule of CH(3)OH is eliminated, and the S-S bond is cleaved.     

Fluorine-fluorine interactions in the solid state: an experimental and theoretical study

The solid state structures of three compounds that contain a perfluorinated chain, CF(3)(CF(2))(5)CH(2)CH(CH(3))CO(2)H, CF(3)(CF(2))(5)(CH(2))(4)(CF(2))(5)CF(3) and {CF(3)(CF(2))(5)CH(2)CH(2)}(3)P═O have been compared and a number of C-F···F-C and C-F···H-C interactions that are closer than the sum of the van der Waals radii have been identified. These interactions have been probed by a comprehensive computational chemistry investigation and the stabilizing energy between dimeric fragments was found to be 0.26-29.64 kcal/mol, depending on the type of interaction. An Atoms-in-Molecules (AIM) study has confirmed that specific C-F···F-C interactions are indeed present, and are not due simply to crystal packing. The weakly stabilizing nature of these interactions has been utilized in the physisorption of a selected number of compounds containing long chain perfluorinated ponytails onto a perfluorinated self-assembled monolayer, which has been characterized by IRRAS (Infrared Reflection Absorption Spectroscopy).     

Silver(I)-organophosphane complexes of electron withdrawing CF3- or NO2-substituted scorpionate ligands

New silver(I) complexes have been synthesized from the reaction of AgNO(3), monodentate tertiary phosphanes PR(3) (PR(3) = P(C(6)H(5))(3), P(o-C(6)H(4)CH(3))(3), P(m-C(6)H(4)CH(3))(3), P(p-C(6)H(4)CH(3))(3), PCH(3)(C(6)H(5))(2)) and two novel electron withdrawing ligands: potassium dihydrobis(3-nitropyrazol-1-yl)borate and potassium dihydrobis(3-trifluoromethylpyrazol-1-yl)borate. These compounds have been characterized by elemental analyses, FT-IR, ESI-MS and multinuclear ((1)H, (19)F and (31)P) NMR spectroscopy. Solid state structures of the potassium salts K[H(2)B(3-(NO(2))pz)(2)] and K[H(2)B(3-(CF(3))pz)(2)] have been reported. They form polymeric networks due to intermolecular contacts of various types between the potassium ion and atoms of the neighboring molecules. The silver adducts [H(2)B(3-(NO(2))pz)(2)]Ag[P(C(6)H(5))(3)](2) and [H(2)B(3-(NO(2))pz)(2)]Ag[P(p-C(6)H(4)CH(3))(3)] have pseudo tetrahedral and trigonal planar silver sites, respectively. The bis(pyrazolyl)borate ligand acts as a kappa(2)-N(2) donor. The nitro-substituents are coplanar with the pyrazolyl rings in all these adducts indicating efficient electron delocalization between the two units. The [H(2)B(3-(CF(3))pz)(2)]Ag[P(C(6)H(5))(3)] complex has been obtained from re-crystallization of {[H(2)B(3-(CF(3))pz)(2)]Ag[P(C(6)H(5))(3)](2)} in a dichloromethane-diethyl ether solution; it is a three-coordinate, trigonal planar silver complex.     

Enols of amides. The effect of fluorine substituents in the ester groups of dicarboalkoxyanilidomethanes on the enol/amide and E-enol/Z-enol ratios. A multinuclei NMR study.

Condensation of phenyl isocyanate substituted by 4-MeO, 4-Me, 4-H, 4-Br, and 2,4-(MeO)(2) with esters CH(2)(CO(2)R)CO(2)R', R = CH(2)CF(3), R' = CH(3), CH(2)CF(3), CH(CF(3))(2), or R = CH(3), R' = CH(CF(3))(2) gave 17 "amides" ArNHCOCH(CO(2)R)CO(2)R' containing three, six, or nine fluorines in the ester groups. X-ray crystallography of six of them revealed that compounds with > or =6 fluorine atoms exist in the solid state as the enols of amides ArNHC(OH)=C(CO(2)R)CO(2)R' whereas the ester with R = R' = CH(3) was shown previously to have the amide structure. In the solid enols, the OH is cis and hydrogen bonded to the better electron-donating (i.e., with fewer fluorine atoms) ester group. X-ray diffraction could not be obtained for compounds with only three fluorine atoms, i.e., R = CH(2)CF(3), R' = CH(3) but the (13)C CP-MAS spectra indicate that they have the amide structure in the solid state, whereas esters with six and nine fluorine atoms display spectra assigned to the enols. The solid enols show unsymmetrical hydrogen bonds and the expected features of push-pull alkenes, e.g., long C(alpha)=C(beta) bonds. The structure in solution depends on the number of fluorine atoms and the solvent, but only slightly on the substituents. The symmetrical systems (R = R' = CH(2)CF(3)) show signals for the amide and the enol, but all systems with R not equal R' displayed signals for the amide and for two enols, presumably the E- and Z-isomers. The [Enol I]/[Enol II] ratio is 1.6-2.9 when R = CH(2)CF(3), R' = CH(3), CH(CF(3))(2) and 4.5-5.3 when R = CH(3), R' = CH(CF(3))(2). The most abundant enol display a lower field delta(OH) and a higher field delta(NH) and assigned the E-structure with a stronger O-H.O=C(OR) hydrogen bond than in the Z-isomer. delta(OH) and delta(NH) values are nearly the same for all systems with the same cis CO(2)R group. The [Enols]/[Amide] ratio in various solvents follows the order CCl(4) > CDCl(3) > CD(3)CN > DMSO-d(6). The enols always predominate in CCl(4) and the amide is the exclusive isomer in DMSO-d(6) and the major one in CD(3)CN. In CDCl(3) the major tautomer depends on the number of fluorines. For example, in CDCl(3,) for Ar = Ph, the % enol (K(Enol)) is 35% (0.54) for R = CH(2)CF(3,) R' = CH(3), 87% (6.7) for R = R' = CH(2)CF(3), 79% (3.8) for R = CH(3), R' = CH(CF(3))(2) and 100% (> or =50) for R = CH(2)CF(3), R' = CH(CF(3))(2). (17)O and (15)N NMR spectra measured for nine of the enols are consistent with the suggested assignments. The data indicate the importance of electron withdrawal at C(beta), of intramolecular hydrogen bonding, and of low polarity solvents in stabilizing the enols. The enols of amides should no longer be regarded as esoteric species.     

Syntheses, derivatives, solubility, and interfacial properties of 2-methyl-2-polyfluoroalkenyloxymethyl-1,3-propanediols: potential building blocks for syntheses of amphiphatic macromolecules

2-Hydroxymethyl-2-methyl-1,3-propanediol (A) was reacted with (Me(3)Si)(2)NH and toluenesulfonyl chloride (TsCl) to give mainly CH(3)C(CH(2)OSiMe(3))(3) (1), and CH(3)C(CH(2)OTs)(3) (2), respectively. With allyl bromide, the products were CH(3)C(CH(2)OCH(2)CH[double bond]CH(2))(2)(CH(2)OH) (3) and CH(3)C(CH(2)OCH(2)CH[double bond]CH(2))(CH(2)OH)(2) x H(2)O (4). The reactions of 4 with perfluoroalkyl iodides (R(f)I) were catalyzed by Cu(I)Cl to form 2-methyl-2-polyfluoroalkenyloxymethyl-1,3-propanediols: (R(f)CH=CHCH(2)OCH(2))C(Me)(CH(2)OH)(2) [R(f) = C(4)F(9) (5), C(8)F(17) (6), and (CF(2)CF(2))(4)OCF(CF(3))(2) (7)]. Reduction of 5 and 6 with hydrogen gave two new 2-methyl-2-polyfluoroalkyloxymethyl-1,3-propanediols, 8 and 9. The sodium salt of 9 was reacted with allyl bromide or acetyl chloride to form (C(8)F(17)CH(2)CH(2)CH(2)OCH(2))C(Me)(CH(2)OX)(CH(2)OH)(2) [where X = CH(2)CH=CH(2) (10) or C(O)CH(3) (12)] and (C(8)F(17)CH(2)CH(2)CH(2)OCH(2))C(Me)(CH(2)OX)(2) [where X = CH(2)CH[double bond]CH(2) (11) or C(O)CH(3) (13)]. Reaction of tolenesulfonyl chloride with 7 gave the monotosylate, 14, as the sole product. With 4-trifluoromethylbenzyl bromide, the sodium salt of 4 gave (4-CF(3)C(6)H(4)CH(2)OCH(2))C(Me)(CH(2)CH[double bond]CH(2))(CH(2)OH) x H(2)O (15). The compounds were characterized by NMR ((1)H, (13)C, (19)F, (29)Si), GC-MS, and high-resolution MS or elemental analyses. UV evidence was obtained for partitioning of 9, 12, 14, and 15 between perfluorodecalin and n-octanol. The test compounds acted as surfactants by facilitating the solubility of phenol and Si(CH[double bond]CH(2))(4) in perfluorodecalin. The single-crystal X-ray structure of 8 was also obtained. It crystallized in the monoclinic space group P2(1)/c, and unit cell dimensions were a = 24.966(2) A (alpha = 90), b = 6.1371(6) A (beta = 100.730(2)), and c = 10.5669(10) A (gamma = 90).     

1H,1H,2H,2H-perfluoroalkyl-functionalization of Ni(II), Pd(II), and Pt(II) mono- and diphosphine complexes: minimizing the electronic consequences for the metal center

A series of fluorous derivatives of group 10 complexes MCl(2)(dppe) and [M(dppe)(2)](BF(4))(2) (M = Ni, Pd or Pt; dppe = 1,2-bis(diphenylphosphino)ethane) and cis-PtCl(2)(PPh(3))(2) was synthesized. The influence of para-(1H,1H,2H,2H-perfluoroalkyl)dimethylsilyl-functionalization of the phosphine phenyl groups of these complexes, as studied by NMR spectroscopy, cyclovoltammetry (CV), XPS analyses, as well as DFT calculations, points to a weak steric and no significant inductive electronic effect. The steric effect is most pronounced for M = Ni and leads in the case of NiCl(2)(1c) (3c) and [Ni(1c)(2)](BF(4))(2) (7c) (1c = [CH(2)P[C(6)H(4)(SiMe(2)CH(2)CH(2)C(6)F(13))-4](2)](2)) to a tetrahedral distortion from the expected square planar geometry. The solubility behavior of NiCl(2)[CH(2)P[C(6)H(4)(SiMe(3-b)(CH(2)CH(2)C(x)F(2x+1)b)-4](2)](2) (3: b = 1-3; x = 6, 8) in THF, toluene, and c-C(6)F(11)CF(3) was found to follow the same trends as those observed for the free fluorous ligands 1. A similar correlation between the partition coefficient (P) of complexes 3 and free 1 was observed in fluorous biphasic solvent systems, with a maximum value obtained for 3f (b = 3, x = 6, P = 23 in favor of the fluorous phase).     

Structural changes, P-P bond energies, and homolytic dissociation enthalpies of substituted diphosphines from quantum mechanical calculations

The molecular structures of the diphosphines P(2)[CH(SiH(3))(2)](4), P(2)[C(SiH(3))(3)](4), P(2)[SiH(CH(3))(2)](4), and P(2)[Si(CH(3))(3)](4) and the corresponding radicals P[CH(SiH(3))(2)](2), P[C(SiH(3))(3)](2), P[SiH(CH(3))(2)](2), and P[Si(CH(3))(3)](2) were predicted by theoretical quantum chemical calculations at the HF/3-21G*, B3LYP/3-21G*, and MP2/6-31+G* levels. The conformational analyses of all structures found the gauche conformers of the diphosphines with C(2) symmetry to be the most stable. The most stable conformers of the phosphido radicals were also found to possess C(2) symmetry. The structural changes upon dissociation allow the release of some of the energy stored in the substituents and therefore contribute to the decrease of the P-P bond dissociation energy. The P-P bond dissociation enthalpies at 298 K in the compounds studied were calculated to vary from -11.4 kJ mol(-1) (P(2)[C(SiH(3))(3)](4)) to 179.0 kJ mol(-1) (P(2)[SiH(CH(3))(2)](4)) at the B3LYP/3-21G* level. The MP2/6-31+G* calculations predict them to be in the range of 52.8-207.9 kJ mol(-1). All the values are corrected for basis set superposition error. The P-P bond energy defined by applying a mechanical analogy of the flexible substituents connected by a spring shows less variation, between 191.3 and 222.6 kJ mol(-1) at the B3LYP/3-21G level and between 225.6 and 290.4 kJ mol(-1) at the MP2/6-31+G* level. Its average value can be used to estimate bond dissociation energies from the energetics of structural relaxation.     

Cyclo- and carbophosphazene-supported ligands for the assembly of heterometallic (Cu2+/Ca2+, Cu2+/Dy3+, Cu2+/Tb3+) complexes: synthesis, structure, and magnetism

The carbophosphazene and cyclophosphazene hydrazides, [{NC(N(CH(3))(2))}(2){NP{N(CH(3))NH(2)}(2)}] (1) and [N(3)P(3)(O(2)C(12)H(8))(2){N(CH(3))NH(2)}(2)] were condensed with o-vanillin to afford the multisite coordination ligands [{NC(N(CH(3))(2))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-OH)(m-OCH(3))}(2)}] (2) and [{N(2)P(2)(O(2)C(12)H(8))(2)}{NP{N(CH(3))N═CH-C (6)H(3)-(o-OH)(m-OCH(3))}(2)}] (3), respectively. These ligands were used for the preparation of heterometallic complexes [{NC(N(CH(3))(2))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{CuCa(NO(3))(2)}] (4), [{NC(N(CH(3))(2))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{Cu(2)Ca(2)(NO(3))(4)}]·4H(2)O (5), [{NC(N(CH(3))(2))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{CuDy(NO(3))(4)}]·CH(3)COCH(3) (6), [{NP(O(2)C(12)H(8))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{CuDy(NO(3))(3)}] (7), and [{NP(O(2)C(12)H(8))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{CuTb(NO(3))(3)}] (8). The molecular structures of these compounds reveals that the ligands 2 and 3 possess dual coordination pockets which are used to specifically bind the transition metal ion and the alkaline earth/lanthanide metal ion; the Cu(2+)/Ca(2+), Cu(2+)/Tb(3+), and Cu(2+)/Dy(3+) pairs in these compounds are brought together by phenoxide and methoxy oxygen atoms. While 4, 6, 7, and 8 are dinuclear complexes, 5 is a tetranuclear complex. Detailed magnetic properties on 6-8 reveal that these compounds show weak couplings between the magnetic centers and magnetic anisotropy. However, the ac susceptibility experiments did not reveal any out of phase signal suggesting that in these compounds slow relaxation of magnetization is absent above 1.8 K.     

Fluorinated aminoalkoxide and ketoiminate indium complexes as MOCVD precursors for In2O3 thin film deposition

The syntheses of two distinctive types of indium complex derived from trimethylindium (InMe(3)) are reported. The first kind has a generalized structural formula [InMe(2)(amak)](2), where (amak)H is an abbreviation for a series of chelating amino alcohol ligands HOC(CF(3))(2)CH(2)NHR, R = (CH(2))(2)OMe (1), Me (2), and Bu(t) (3), as well as HOC(CF(3))(2)CH(2)NMe(2) (4); while the second type of complex is illustrated by [InMe(2)(keim)] (5), for which (keim)H is a tridentate ketoimine ligand of structural formula O=C(CF(3))CH(2)C(CF(3))=NCH(2)CH(2)NMe(2). The solid-state structures of 2 and 5 were determined using single crystal X-ray diffraction studies. For the aminoalkoxide complexes 2-4, the existence of dimeric In(2)O(2) core structures in the solid state has been established with the amino fragment located trans to the alkoxide ligands, in a molecular arrangement which is in contrast to the distorted, trigonal bipyramidal geometry observed for the ketoiminate complex 5. Moreover, VT NMR studies of 2 revealed a rapid dimer-to-monomer equilibration and simultaneous rupture of the N-->In dative interaction, affording two interconvertible isomers related by having the N-Me substituents in either trans or cis dispositions. For complexes 2 and 5, deposition of In(2)O(3) thin films was successfully conducted at temperatures 400-500 degrees C, using O(2) as the carrier gas to induce indium oxide deposition and to suppress carbon impurity present in the thin film. Scanning electron micrographs (SEMs) revealed the surface morphologies. The atomic composition of these films was examined by both X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering (RBS) methods, while X-ray diffraction studies (XRD) confirmed the formation of a preferred orientation along the (222) planes.     

Stable enols of amides ArNHC(OH)=C(CN)CO(2)R. E/Z enols,equilibria with the amides,solvent effects,and hydrogen bonding

The structures of anilido cyano(fluoroalkoxycarbonyl)methanes ArNHCOCH(CN)CO(2)R, where R = CH(2)CF(3) or CH(CF(3))(2), Ar = p-XC(6)H(4), and X = MeO, Me, H, or Br, were investigated. In the solid state, all exist as the enols ArNHC(OH)=C(CN)CO(2)R 7 (R = CH(2)CF(3)) and 9 (R = CH(CF(3))(2)) with cis arrangement of the hydrogen-bonded ROC=O.HO moiety and a long C1=C2 bond. The product composition in solution is solvent dependent. In CDCl(3) solution, only a single enol is observed, whereas in THF-d(8) and CD(3)CN, two enols (E and Z) are the major products, and the amide is the minor product or not observed at all (K(Enol) 1.04-9 (CD(3)CN, 298 K) and 3 to >/=100 (THF, 300 K)). The percentage of the amide and the Z-enol increase upon an increase in temperature. In all solvents, the percent enol is higher for 9 than for 7. In CD(3)CN, more enol is observed when the aryl group is more electron-donating. The spectra in DMSO-d(6) and DMF-d(7) indicate the presence of mostly a single species, whose spectra do not change on addition of a base and is ascribed to the anion of the ionized carbon acid. Comparison with systems where the CN is replaced by a CO(2)R group (R = CH(2)CF(3), CH(CF(3))(2)) shows a higher percentage of enol for the CN-substituted system. Intramolecular (to CO(2)R) and intermolecular hydrogen bonds determine, to a significant extent, the stability of the enols, their Z/E ratios (e.g., Z/E (THF, 240 K) = 3.2-4.0 (7) and 0.9-1.3 (9)), and their delta(OH) in the (1)H spectra. The interconversion of Z- and E-enol by rotation around the C=C bond was studied by DNMR, and DeltaG() values of >/=15.3 and 14.1 +/- 0.4 kcal/mol for Z-7 and Z-9 were determined. Features of the NMR spectra of the enols and their anions are discussed.     

Facile allylic C-H bond activation on the bridging disulfide ligand in the Ru(III) dinuclear complex having a conjugated RuSSRu core

Treatment of [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)(mu-S(2))](CF(3)SO(3))(4) (1), which is prepared by the reaction of [[RuCl(P(OCH(3))(3))(2)](2)(mu-S(2))(mu-Cl)(2)] (2) with 4 equiv of AgCF(3)SO(3), with terminal alkenes such as 1-pentene, allyl ethyl ether, allyl phenyl ether, 1,4-hexadiene, and 3-methyl-1-butene, resulted in the formation of complexes carrying a C(3)S(2) five-membered ring, [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(2)CH(2)CR(1)R(2)S]](CF(3)SO(3))(4) (3, R(1) = CH(2)CH(3), R(2) = H, 40%; 4, R(1) = OCH(2)CH(3), R(2) = H, 60%; 5, R(1) = OC(6)H(5), R(2) = H, 73%; 6, R(1) = CH=CHCH(3), R(2) = H, 48%; 7, R(1) = R(2) = CH(3), 40%). Reaction of 1 with methylenecycloalkanes was found to give several different types of products, depending on the ring size of the substrates. A trace of [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-SCH(CH(2)CH(2))CH(CH(3))S]](CF(3)SO(3))(4) (9) having a C(2)S(2) four-membered ring to bridge the two Ru atoms was obtained by the reaction of 1 with methylenecyclobutane, whereas the reaction with methylenecyclohexane gave [[Ru(P(OCH(3))(3))(2)(CH(3)CN)(3)](2)[mu-S(CH(2)(C=CHCH(2)CH(2)CH(2)CH(2))S)](CF(3)SO(3))(3) (10) in 69% yield via C-S bond formation and elimination of a proton. Throughout these reactions with alkenes giving a variety of products, the activation of the allylic C-H bond is always the essential and initial key step.     

Syntheses and structures of thermally stable diketiminato complexes of gold and copper

While most metallic elements across the Periodic Table form stable chelating β-diketiminato complexes, examples of Au(I) are conspicuous by their absence. We report here the reaction of K[HC(F(3)CC=NR)(2)] with AuCl(PPh(3)) which provides a rare example of a thermally stable gold(I) diketiminato complex, (Ph(3)P)Au[RN=C(CF(3))CH(CF(3))C=NR] [R = 3,5-C(6)H(3)(CF(3))(2)]. The complex is highly fluxional in solution but in the solid state adopts a U-conformation. By contrast, the analogous reaction of K[HC(F(3)CC=NR)(2)] with CuBr(PPh(3))(3) gives the rigid 18-electron chelate complex (Ph(3)P)(2)Cu[κ(2)-HC{(CF(3))C=NR}(2)].     

Reaction of organylxenonium(II) salts, [RXe][Y], with organyl iodides, R'I, in anhydrous HF: scope and limitation of a new synthetic approach to iodonium salts, [RR'I][Y

Perfluoroalkynylxenonium salts, [RXe][BF(4)] (R = CF(3)C≡C, (CF(3))(2)CFC≡C), reacted with organyl iodides, R'I (R' = 3-FC(6)H(4), C(6)F(5), CF(2)═CF, CF(3)CH(2); no reaction with R' = CF(3)CF(2)CF(2)) in anhydrous HF to yield the corresponding asymmetric polyfluorinated iodonium salts, [RR'I][Y]. The action of the arylxenonium salt, [C(6)F(5)Xe][BF(4)], and the cycloalkenylxenonium salt, [cyclo-1,4-C(6)F(7)Xe][AsF(6)], on 4-FC(6)H(4)I gave [C(6)F(5)(4-FC(6)H(4))I][BF(4)] and [cyclo-1,4-C(6)F(7)(4-FC(6)H(4))I][AsF(6)], respectively, besides the symmetric iodonium salt, [(4-FC(6)H(4))(2)I][Y]. But the aryl-, as well as the cycloalkenylxenonium salt, did not react with C(6)F(5)I, CF(2)═CFI, and CF(3)CH(2)I.     

Mechanism of vinylic and allylic carbon-fluorine bond activation of non-perfluorinated olefins using Cp*(2)ZrH(2)

Cp(2)ZrH(2) (1) (Cp = pentamethylcyclopentadienyl) reacts with vinylic carbon-fluorine bonds of CF(2)=CH(2) and 1,1-difluoromethylenecyclohexane (CF(2)=C(6)H(10)) to afford Cp(2)ZrHF (2) and hydrodefluorinated products. Experimental evidence suggests that an insertion/beta-fluoride elimination mechanism is occurring. Complex 1 reacts with allylic C-F bonds of the olefins, CH(2)=CHCF(3), CH(2)=CHCF(2)CF(2)CF(2)CF(3), and CH(2)=C(CF(3))(2) to give preferentially 2 and CH(3)-CH=CF(2), CH(3)-CH=CF-CF(2)CF(2)CF(3), and CF(2)=C(CF(3))(CH(3)), respectively, by insertion/beta-fluoride elimination. In the reactions of 1 with CH(2)=CHCF(3) and CH(2)=CHCF(2)CF(2)CF(2)CF(3), both primary and secondary alkylzirconium olefin insertion intermediates were observed in the (1)H and (19)F NMR spectra at low temperature. A deuterium labeling study revealed that more than one olefin-dihydride complex is likely to exist prior to olefin insertion. In the presence of excess 1 and H(2), CH(2)=CHCF(3) and CH(2)=CHCF(2)CF(2)CF(2)CF(3) are reduced to propane and (E)-CH(3)CH(2)CF=CFCF(2)CF(3), respectively.     

Aggregation properties of cationic gemini surfactants with partially fluorinated spacers in aqueous solution

The aggregation properties of cationic gemini surfactants alkanediyl-alpha,omega-bis(dodecyldimethylammonium bromide), [C(12)H(25)(CH(3))(2)N(CH(2))(m)(CF(2))(n)(CH(2))(m))N(CH(3))(2)C(12)H(25)]Br(2) [where 2m + n = 12 and n = 0, 4, and 6; designated as 12-12-12, 12-12(C(4)(F))-12, and 12-12(C(6)(F))-12, respectively] have been studied by microcalorimetry, time-resolved fluorescence quenching, and electrical conductivity. Compared with a fully hydrocarbon spacer of 12-12-12, the fluorinated spacer with a lower ratio of CF(2) to CH(2) in 12-12(C(4)(F))-12 tends to disfavor the aggregation, leading to larger critical micelle concentration (cmc), lower micelle aggregation number (N), and less negative Gibbs free energy of micellization (DeltaG(mic)). However, the fluorinated spacer with a higher ratio of CF(2) to CH(2) in 12-12(C(6)(F))-12 may prompt the aggregation, resulting in lower cmc, higher N, and more negative DeltaG(mic). It is also noted that enthalpy change of micellization (DeltaH(mic)) for 12-12(C(4)(F))-12 is the most exothermic, but the values of DeltaH(mic) for 12-12-12 and 12-12(C(6)(F))-12 are almost the same. These results are rationalized in terms of competition among the enhanced hydrophobicity and the rigidity of the fluorinated spacer, and the variation of immiscibility of the fluorinated spacer with the hydrocarbon side chains.     

How to insulate a reactive site from a perfluoroalkyl group: photoelectron spectroscopy, calorimetric, and computational studies of long-range electronic effects in fluorous phosphines P((CH(2))(m)(CF(2))(7)CF(3))(3)

This study advances strategy and design in catalysts and reagents for fluorous and supercritical CO(2) chemistry by defining the structural requirements for insulating a typical active site from a perfluoroalkyl segment. The vertical ionization potentials of the phosphines P((CH(2))(m)R(f8))(3) (m = 2 (2) to 5 (5)) are measured by photoelectron spectroscopy, and the enthalpies of protonation by calorimetry (CF(3)SO(3)H, CF(3)C(6)H(5)). They undergo progressively more facile (energetically) ionization and protonation (P(CH(2)CH(3))(3) > 5 > 4 approximately equal to P(CH(3))(3) > 3 > 2), as expected from inductive effects. Equilibrations of trans-Rh(CO)(Cl)(L)(2) complexes (L = 2, 3) establish analogous Lewis basicities. Density functional theory is used to calculate the structures, energies, ionization potentials, and gas-phase proton affinities (PA) of the model phosphines P((CH(2))(m)()CF(3))(3) (2'-9'). The ionization potentials of 2'-5' are in good agreement with those of 2-5, and together with PA values and analyses of homodesmotic relationships are used to address the title question. Between 8 and 10 methylene groups are needed to effectively insulate a perfluoroalkyl segment from a phosphorus lone pair, depending upon the criterion employed. Computations also show that the first carbon of a perfluoroalkyl segment exhibits a much greater inductive effect than the second, and that ionization potentials of nonfluorinated phosphines P((CH(2))(m)CH(3))(3) reach a limit at approximately nine carbons (m = 8).     

Synthesis and characterization of silver(I) adducts supported solely by 1,3,5-triazapentadienyl ligands or by triazapentadienyl and other N-donors

Halogenated 1,3,5-triazapentadienyl ligands [N{(C(3)F(7))C(C(6)F(5))N}(2)](-), [N{(CF(3))C(C(6)F(5))N}(2)](-) and [N{(C(3)F(7))C(2,6-Cl(2)C(6)H(3))N}(2)](-), alone or in combination with other N-donors like CH(3)CN, CH(3)(CH(2))(2)CN, and N(C(2)H(5))(3), have been used in the stabilization of thermally stable, two-, three- or four-coordinate silver(i) adducts. X-Ray crystallographic analyses of {[N{(C(3)F(7))C(C(6)F(5))N}(2)]Ag}(n), {[N{(C(3)F(7))C(C(6)F(5))N}(2)]Ag(NCCH(3))}(n), {[N{(C(3)F(7))C(2,6-Cl(2)C(6)H(3))N}(2)]Ag(NCCH(3))}(n), {[N{(CF(3))C(C(6)F(5))N}(2)]Ag(NCCH(3))(2)}(n) and {[N{(C(3)F(7))C(C(6)F(5))N}(2)]Ag(NCC(3)H(7))}(n) revealed the presence of bridging 1,3,5-triazapentadienyl ligands bonded to silver through terminal nitrogen atoms. These adducts are polymeric in the solid state. [N{(C(3)F(7))C(2,6-Cl(2)C(6)H(3))N}(2)]AgN(C(2)H(5))(3) is monomeric and features a 1,3,5-triazapentadienyl ligand bonded to Ag(I) in a κ(1)-fashion via only one of the terminal nitrogen atoms. The solid state structure of [N{(C(3)F(7))C(C(6)F(5))N}(2)]H has also been reported and it forms polymeric chains via inter-molecular N-H···N hydrogen-bonding.