The reaction of TiF4 with Li(OC(CF3)2Ph): direct synthetic route to the lithium-titanium heterometallic fluoride bridged complex {Li(THF)2TiF3(OC(CF3)2Ph)2}2 and Ti(OC(CF3)2Ph)4 alkoxide

Reaction of TiF4 and LiORf (Rf = C(CF3)2Ph) in the donor solvent-THF lead to the isolation of the heterometallic lithium-titanium complex (THF)2Li(mu-F)2Ti(ORf)2(mu-F)2Ti(ORf)(2)(mu-F)2Li(THF)2 (1) and Ti(ORf)4 alkoxide (2). Interaction of TiF4 and LiORf in the non-coordinating and low polar toluene yielded only Ti(ORf)4 (2). Compounds 1 and 2 were characterized by X-ray single-crystal analysis, IR, NMR and mass spectrometry. Compound 1 is a centrosymmetric fluorine bridged dimer and contains the Li(mu-F)2Ti(mu-F)2Ti(mu-F)2Li cage. Complex 2 containing four bulky ligands is monomeric. NMR evidence is presented that the TiF4 and LiORf in THF solution gave lithium-titanium heterometallic complexes containing Li-(mu-F)-Ti and the Ti-(mu-F)-Ti bonds.     

Ph(3)PCH(2)Ph](2)[Zn(3)(tp)(3)Cl(2)] and Ni(3)(tma)(2)(H(2)O)(8): two unusual claylike frameworks of metal-polycarboxylate coordination polymers (tp = terephthalate, tma = trimesate)

Two new compounds, [Ph3PCH2Ph]2[Zn3(tp)3Cl2] (1) and Ni3(tma)2(H2O)8 (2) (tp = terephthalate, tma = trimesate), are metal-polycarboxylate coordination polymers prepared by similar hydrothermal synthesis techniques. X-ray single-crystal structural analysis shows that both compounds crystallize in the 2D claylike lamellar architectures, in which 1 possesses the interlayer [Ph3PCH2Ph]+ exchangeable cation and has been confirmed by PXRD patterns. 1 (C74H56Cl2O12P2Zn3) belongs to monoclinic P21/c, Z = 2 (a = 18.956(1) A, b = 10.2697(5) A, c = 17.067(1) A, beta = 99.486(4) degrees ). 2 (C18H22O20Ni3) is attributed to triclinic P, Z = 1 (a = 6.6643(8) A, b = 9.622(1) A, c = 10.089(1) A, alpha = 112.675(2) degrees , beta = 94.007(1) degrees, gamma = 106.411(2) degrees ). Linear metal trinuclear clusters bridged by rigid linear tp ligands for 1 and trigonal tma ligands for 2 give rise to a novel 2D 6-linked (3,6) topological anionic network in 1 and an interesting 2D 3,6-linked molybdenite topological neutral network in 2, respectively. Both compounds exhibit intense fluorescent emission bands at 410 nm (lambda(exc) = 355 nm) for 1 and 398 nm (lambda(exc) = 300 nm) for 2 in the solid state at room temperature.     

Redox reaction on treating fac- or mer- [Mo(CO)3(dppm-PP')(dppm-P)] (dppm = Ph2PCH2PPh2) with Hg(SCN)2 and crystal structure of the seven-coordinate product [Mo(CO)2(NCS)2(dppm-PP')(dppm-P)]

[Mo(CO)₂(NCS)₂(dppm-PP')(dppm-P)] (dppm = Ph₂PCH₂PPh₂) is formed in a rapid and clean redox reaction when fac- or mer-[Mo(CO)₃(dppm-PP')(dppm-P)] is treated with Hg(SCN)₂: dppm-chelate ring-opening with formation of a heterobimetallic species is not observed. The X-ray crystal structure of the product shows the molecule to contain seven-coordinate Mo(II) with “cis” CO groups, both monodentate and chelating dppm ligands, and with N-bonded NCS groups. The coordination geometry is intermediate between a capped trigonal prism and a capped octahedron. Crystals of [Mo(CO)₂ (NCS)₂(dppm-PP')(dppm-P)] are orthorhombic, space group Pna2₁, with a = 21.583(7) Å, b = 12.775(4) Å, c = 18.484(5) Å, and Z = 4; the final R factor was 0.046 for 3181 observed reflections.     

Über Sn[OCH(CF3)2]2 und Sn (OCH2CF3)2 (n = 1, 2)

On S_n[OCH(CF₃)₂]₂ and S_n(OCH₂CF₃)₂ (n = 1, 2) The sulfoxylates S[OCH(R)CF₃]₂, 1 and 2 and the disulfides S₂[OCH(R)CF₃]₂, 5 and 6 (R = CF₃, H) are obtained by reacting SCl₂ or S₂Cl₂, respectively, and the lithium alcoxides LiOCH(R)CF₃. Chlorine and compound 2 give ClS(O)OCH₂F₃ and CF₃CH₂Cl, whereas the sulfur-sulfur bound is cleaved in 5 and 6 furnishing SCI₂, 1 and 2 , respectively. The ¹⁹F n.m.r. spectrum of 5 and the ¹H n.m.r. spectrum of 6 are interpreted in terms of hindered rotation about the sulfur-sulfur axis.     

The crystal and molecular structure of PtCl(CF3)(cis-Ph2PCH=CHPPh2)

Summary The structure of PtCl(CF₃)(cis-Ph₂PCH=CHPPh₂), has been determined from three-dimensional x-ray data. The complex crystallizes in the monoclinic system, space group C _2h ⁵ -P2₁/n witha=19.781(6),b=15.024(5),c=8.547(3) Å,=93.2(1)° andZ=4. Least-squares refinement has led to a value of the conventional R index (on F) of 0.055 for the 3199 independent reflections having I2.5 (I). The complex is a typical square-planar Pt^II complex with structural parameters: Pt-P, 2.275(4) (a)trans to CF₃ and 2.236(4) (b)trans to Cl, Pt-Cl, 2.346(4), Pt-C(F), 2.188(8), C(A) = C(B), 1.38(2) Å; Cl-Pt-P(1), 91.1(1), P(1)-Pt-P(2), 86.2(1)°.     

Complex [MoO2(L)(CH3OH)] (L2- = 3-methoxysalicylidenemonoethanolimine anion): Synthesis,crystal and molecular structures

The complex [MoO₂(L)(CH₃OH)] (where L^2- is 3-methoxysalicylidenemonoethanolimine anion) has been prepared and structurally characterized by X-ray diffraction. The molybdenum atom has an octahedral coordination to two ligands in cis-positions to each other, two oxygen atoms, the nitrogen atom of the tridentate bis(chelate) L^2- ligand, and also the oxygen atom of methanol. Strong O-H?O hydrogen bonds (O?O, 2.598 Å) link pairs of molecules into centrosymmetric pseudo-dimers.     

Molecular and crystal structures of Ph2P(O)(CH2)2OH and Ph2P(O)CH2(C6H6)OH

The molecular and crystal structures of Ph₂P(O)(CH₂)₂OH and Ph₂P(O)CH₂(C₆H₆)OH have been determined. For the first compound the space group is with unit cell dimensions a=10.505(2), b=13.720(2), c=14.782(3) Å; =72.58(6), =76.95(6), =72.49(6)° for Z=6 (Syntex diffractometer,MoK radiation, 2996 reflections, R=3.2%). The second compound crystallizes in the space group P2₁2₁2₁ with unit cell dimensions a=9.371(3), b=9.014(3), c=18.461(5) Å for Z=4 (DAR-UM diffractometer,CuK radiation, 909 reflections, R=4.9%). In Ph₂P(O)(CH₂)₂OH, three independent molecules differing in structural details are linked by the P=O...O hydrogen bonds (O...H is 1.84, 1.80, and 1.86 Å), to form a chain. In Ph₂P(O)CH₂(C₆H₆)OH, the molecules are joined by pairs of the P=O...H–O bonds (O...H is 1.81 Å) to form 16-membered dimeric associates.Institute of Chemical Physics, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 3, pp. 109–118, May–June 1993.Translated by T. Yudanova     

CF bond activation in the reaction of BiCl3 with sodium 2,4,6-tris(trifluoromethyl)phenoxide

BiCl₃ reacts with sodium 2,4,6-tris(trifluoromethyl)phenoxide (NaOR_4f) in ether solution to produce an unusual condensation product in which three OR_f functions have been coupled with the elimination of three fluorine atoms. The product is R_fOC₆H₂(CF₃)₂C(O)OR_f, which has been characterized spectroscopically and by X-ray crystallography (triclinic space group P 1; a = 8.958(1), b = 12.652(2), c = 13.722(2)Å, α = 89.596(8)°, β = 75.92(1)°, γ = 71.412(7)°, V = 1425.6(3)ų, Z = 2). Bi(OR_f)₃ is believed to be an intermediate in this process. The carbonfluorine bond activation is not observed in the absence of BiCl₃.     

Hydrolysis of tin(II) neo-pentoxide: syntheses, characterization, and X-ray structures of [Sn(ONep)(2)](infinity), Sn(5)(mu(3)-O)(2)(mu-ONep)(6), and Sn(6)(mu(3)-O)(4)(mu-ONep)(4) where ONep = OCH(2)CMe(3)

The reaction of [Sn(NMe(2))(2)](2) (1) with 4 equiv of HOCH(2)CMe(3) (HONep) leads to the isolation of [Sn(ONep)(2)](infinity) (2). Each Sn atom is four coordinated with mu-ONep ligands bridging the metal centers; however, if the free electrons of the Sn(II) metal center are considered, each Sn center adopts a distorted trigonal bipyramidal (TBP) geometry. Through (119)Sn NMR experiments, the polymeric compound 2 was found to be disrupted into smaller oligomers in solution. Titration of 2 with H(2)O led to the identification of two unique hydrolysis products characterized by single-crystal X-ray diffraction as Sn(5)(mu(3)-O)(2)(mu-ONep)(6) (3) and Sn(6)(mu(3)-O)(4)(mu-ONep)(4) (4). Compound 3 consists of an asymmetrical molecule that has five Sn atoms arranged in a square-based pyramidal geometry linked by four basal mu-ONep ligands, two facial mu(3)-O, and two facial mu-ONep ligands. Compound 4 was solved in a novel octahedral arrangement of six Sn cations with an asymmetric arrangement of mu(3)-O and mu-ONep ligands that yields two square base pyramidal and four pyramidal coordinated Sn cations. These compounds were further identified by multinuclear ((1)H, (13)C, (17)O, and (119)Sn) solid-state MAS and high resolution, solution NMR experiments. Because of the complexity of the compounds and the accessibility of the various nuclei, 2D NMR experiments were also undertaken to elucidate the solution behavior of these compounds. On the basis of these studies, it was determined that while the central core of the solid-state structures of 3 and 4 is retained, dynamic ligand exchange leads to more symmetrical molecules in solution. Novel products 3 and 4 lend structural insight into the stepwise hydrolysis of Sn(II) alkoxides.     

Atmospheric chemistry of CF3OCF2CF2H and CF3OC(CF3)2H: reaction with Cl atoms and OH radicals, degradation mechanism, global warming potentials, and empirical relationship between k(OH) and k(Cl) for organic compounds

Using FTIR smog chamber techniques, k(Cl + CF3OCF2CF2H) = (2.70 +/- 0.52) x 10(-16), k(OH + CF3OCF2CF2H) = (2.26 +/- 0.18) x 10(-15), k(Cl + CF3OC(CF3)2H) = (1.58 +/- 0.27) x 10(-18) and k(OH + CF3OC(CF3)2H) = (3.26 +/- 0.95) x 10(-16) cm3 molecule(-1) s(-1) were measured. The atmospheric lifetimes of CF3OCF2CF2H and CF3OC(CF3)2H are estimated to be 27 and 216 years, respectively. Chlorine atom initiated oxidation of CF3OCF2CF2H in 700 Torr of air in the presence of NO(x) gives CF3OC(O)F in a molar yield of 36 +/- 5% and COF2 in a molar yield of 174 +/- 9%, whereas oxidation of CF3OC(CF3)2H gives CF3OC(O)CF3 and COF2 in molar yields that are indistinguishable from 100%. Quantitative infrared spectra were recorded and used to estimate global warming potentials of 3690 and 8230 (100 year time horizon, relative to CO2) for CF3OCF2CF2H and CF3OC(CF3)2H, respectively. All experiments were performed in 700 Torr of N2/O2 diluent at 296 +/- 2 K. An empirical relationship can be used to estimate the preexponential factor, which can be combined with k(298 K) to give the temperature dependence of reactions of OH radicals with organic compounds proceeding via H-atom abstraction: log(A/n) = (0.239 +/- 0.027) log(k(OH)/n) - (8.69 +/- 0.372), k(OH) is the rate constant at 298 K and n is the number of H atoms. The rates of H-atom abstraction by OH radicals and Cl atoms at 298 K from organic compounds are related by the expression log(k(OH)) = (0.412 +/- 0.049) log(k(Cl)) - (8.16 +/- 0.72). The utility of these expressions and the atmospheric chemistry of the title hydrofluoroethers are discussed.     

CF3CF=CH2 and (Z)-CF3CF=CHF: temperature dependent OH rate coefficients and global warming potentials

Rate coefficients over the temperature range 206-380 K are reported for the gas-phase reaction of OH radicals with 2,3,3,3-tetrafluoropropene (CF(3)CF=CH(2)), k(1)(T), and 1,2,3,3,3-pentafluoropropene ((Z)-CF(3)CF=CHF), k(2)(T), which are major components in proposed substitutes for HFC-134a (CF(3)CFH(2)) in mobile air-conditioning units. Rate coefficients were measured under pseudo-first-order conditions in OH using pulsed-laser photolysis to produce OH and laser-induced fluorescence to detect it. Rate coefficients were found to be independent of pressure between 25 and 600 Torr (He, N(2)). For CF(3)CF=CH(2), the rate coefficients, within the measurement uncertainty, are given by the Arrhenius expression k(1)(T)=(1.26+/-0.11) x 10(-12) exp[(-35+/-10)/T] cm(3) molecule(-1) s(-1) where k(1)(296 K)=(1.12+/-0.09) x 10(-12) cm(3) molecule(-1) s(-1). For (Z)-CF(3)CF=CHF, the rate coefficients are given by the non-Arrhenius expression k(2)(T)=(1.6+/-0.2) x 10(-18)T(2) exp[(655+/-50)/T] cm(3) molecule(-1) s(-1) where k(2)(296 K)=(1.29+/-0.06) x 10(-12) cm(3) molecule(-1) s(-1). Over the temperature range most relevant to the atmosphere, 200-300 K, the Arrhenius expression k(2)(T)=(7.30+/-0.7) x 10(-13) exp[(165+/-20)/T] cm(3) molecule(-1) s(-1) reproduces the measured rate coefficients very well and can be used in atmospheric model calculations. The quoted uncertainties in the rate coefficients are 2sigma (95% confidence interval) and include estimated systematic errors. The global warming potentials for CF(3)CF=CH(2) and (Z)-CF(3)CF=CHF were calculated to be <4.4 and <3.6, respectively, for the 100 year time horizon using infrared absorption cross sections measured in this work, and atmospheric lifetimes of 12 and 10 days that are based solely on OH reactive loss.     

Facile Ar-CF3 bond formation at Pd. Strikingly different outcomes of reductive elimination from [(Ph3P)2Pd(CF3)Ph] and [(Xantphos)Pd(CF3)Ph

Facile and highly selective perfluoroalkyl-aryl reductive elimination from a metal center (Pd) has been demonstrated for the first time. At temperatures as low as 50-80 degrees C, [(Xantphos)Pd(Ph)CF3] undergoes remarkably clean decomposition to produce CF3Ph in high yield and selectivity. In contrast, analogous trifluoromethylpalladium aryls stabilized by rigid cis-chelating ligands such as dppe are completely unreactive at temperatures up to 130-140 degrees C. Decomposition of [(Ph3P)2Pd(Ph)CF3] in the presence of PhI in benzene at 60 degrees C does not produce PhCF3 but rather leads to [(Ph3P)2Pd(Ph)I] and [Ph4P]+[(Ph3P)Pd(CF3)3]- in a 2:1 ratio with high selectivity.     

四氮杂环十二烷铒配合物的合成及其晶体结构

氮气保护下, 在无水乙腈中合成了1, 4, 7, 10-四氮杂环十二烷(Cyclen)与稀土铒的配合物并得到浅红色棱柱状晶体。元素分析结果表明该配合物的组成为Er(Cyclen)(CF3SO3)3(CH3CN)。用X射线衍射方法研究了其单晶结构。晶体属单斜晶系, P21/a空间群。晶胞参数为a=1.7335(4), b=1.8027(4),c=0.8772(3)nm, β=97.64(3)°, V=2.7171(2)nm^3, Z=4。其中铒为八配位,形成四方反棱柱型配位多面体。     

Synthesis, characterization, and structural studies of mixed-ligand diorganotin esters, [R2Sn(OP(O)(OH)Ph)(OS(O)2R1)]n [R = n-Bu, R1 = Me (1), n-Pr(2); R = Et, R1 = Me (3)] with 1D and 3D coordination polymeric motifs

Mixed-ligand diorganotin esters, [R 2Sn(OP(O)(OH)Ph)(OS(O) 2R (1))] n [R = n-Bu, R (1) = Me ( 1), n-Pr ( 2); R = Et, R (1) = Me ( 3)], have been synthesized by reacting the tin precursors, R 2Sn(OR (1))OS(O) 2R with an equimolar amount of phenylphosphonic acid under mild conditions (room temperature, 6-8 h, CH 2Cl 2). These have been characterized by IR, multinuclear ( (1)H, (13)C{ (1)H}, (31)P, and (119)Sn) NMR, and single crystal X-ray diffraction studies. The asymmetric unit of 1 is comprised of a tetramer with four crystallographically unique tin atoms. The structure reveals a central eight-membered (Sn-O-S-O) 2 cyclic ring with two exocyclic tin atoms, which results from micro 3-binding of the two methanesulfonate groups. The remaining two sulfonates are monodentate and contribute in O...HO(P) hydrogen bonding. The molecular structure is extended into a 3D coordination polymer with the aid of hydrogenphenylphosphonate group on each tin atom, acting in a micro 2-O 2P mode and forms a series of eight-membered (Sn-O-P-O) 2 rings in the structural framework. 2 and 3 are isostructural and represent linear 1D coordination polymers via micro 2-binding mode of both alkanesulfonate and hydrogenphenylphosphonate groups.     

Theoretical study and rate constant calculation for reaction of CF(3)CH(2)OH with OH

The reaction mechanism of CF(3)CH(2)OH with OH is investigated theoretically and the rate constants are calculated by direct dynamics method. The potential energy surface (PES) information, which is necessary for dynamics calculation, is obtained at the B3LYP/6-311G (d, p) level. The single-point energy calculations are performed at the MC-QCISD level using the B3LYP geometries. Complexes, with the energies being less than corresponding reactants and products, are found at the entrance and exit channels for methylene-H-abstraction channel, while for the hydroxyl-H-abstraction channel only entrance complex is located. By means of isodesmic reactions, the enthalpies of the formation for the species CF(3)CH(2)OH, CF(3)CHOH, and CF(3)CH(2)O are estimated at the MC-QCISD//B3LYP/6-311G (d, p) level of theory. The rate constants for two kinds of H-abstraction channels are evaluated by canonical variational transition state theory with the small-curvature tunneling correction (CVT/SCT) over a wide range of temperature 200-2000 K. The calculated results are in good agreement with the experimental values in the temperature region 250-430 K. The present results indicate that the two channels are competitive. Below 289 K, hydroxyl-H-abstraction channel has more contribution to the total rate constants than methylene-H-abstraction channel, while above 289 K, methylene-H-abstraction channel becomes more important and then becomes the major reaction channel.     

Synthesis and characterization of diorganotin(IV) derivatives from rhodanine (HRd): crystal structures of [(PhCH2)2Sn(Rd)(μ-OH)]2 and [n-Bu2Sn(Rd)(μ-OH)]2

The diorganotin(IV) complexes, [R₂Sn(Rd)(μ-OH)]₂ (R?=?Me (1), PhCH₂ (2), n-Bu (3), Ph (4); HRd?=?rhodanine), have been synthesized and characterized by IR and multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR spectroscopy. The structures of complexes 2 and 3 have been determined by single-crystal X-ray diffraction. Both crystal structures of 2 and 3 show the presence of asymmetrically bridging hydroxy groups leading to an Sn₂O₂ unit. Each atom in complex 1 is also coordinated by an N atom of ligand and two C atoms of the alkyl groups, so the Sn environment is based on a trigonal bipyramid. While in complex 2, a weak intermolecular Sn–O interaction has also been found between the two adjacent molecules, so the geometry of the Sn atom can be best described as six-coordinate octahedral. The salient feature of the supramolecular structure of complex 3 is that of a 1D polymer, in which the discrete molecules are connected through weak intermolecular Sn?···?O interactions.