OH(3) (-) and O(2)H(5) (-) double Rydberg anions: predictions and comparisons with NH(4) (-) and N(2)H(7) (-)

A low barrier in the reaction pathway between the double Rydberg isomer of OH(3) (-) and a hydride-water complex indicates that the former species is more difficult to isolate and characterize through anion photoelectron spectroscopy than the well known double Rydberg anion (DRA), tetrahedral NH(4) (-). Electron propagator calculations of vertical electron detachment energies (VEDEs) and isosurface plots of the electron localization function disclose that the transition state's electronic structure more closely resembles that of the DRA than that of the hydride-water complex. Possible stabilization of the OH(3) (-) DRA through hydrogen bonding or ion-dipole interactions is examined through calculations on O(2)H(5) (-) species. Three O(2)H(5) (-) minima with H(-)(H(2)O)(2), hydrogen-bridged, and DRA-molecule structures resemble previously discovered N(2)H(7) (-) species and have well separated VEDEs that may be observable in anion photoelectron spectra.     

Tetrachloro- and Tetrabromostibonium(V) Cations: Raman and (19)F, (121)Sb, and (123)Sb NMR Spectroscopic Characterization and X-ray Crystal Structures of SbCl(4)(+)Sb(OTeF(5))(6)(-) and SbBr(4)(+)Sb(OTeF(5))(6)(-)

The stable salts, SbCl(4)(+)Sb(OTeF(5))(6)(-) and SbBr(4)(+)Sb(OTeF(5))(6)(-), have been prepared by oxidation of Sb(OTeF(5))(3) with Cl(2) and Br(2), respectively. The SbBr(4)(+) cation is reported for the first time and is only the second example of a tetrahalostibonium(V) cation. The SbCl(4)(+) cation had been previously characterized as the Sb(2)F(11)(-), Sb(2)Cl(2)F(9)(-), and Sb(2)Cl(0.5)F(10.5)(-) salts. Both Sb(OTeF(5))(6)(-) salts have been characterized in the solid state by low-temperature Raman spectroscopy and X-ray crystallography. Owing to the weakly coordinating nature of the Sb(OTeF(5))(6)(-) anion, both salts are readily soluble in SO(2)ClF and have been characterized in solution by (121)Sb, (123)Sb, and (19)F NMR spectroscopy. The tetrahedral environments around the Sb atoms of the cations result in low electric field gradients at the quadrupolar (121)Sb and (123)Sb nuclei and correspondingly long relaxation times, allowing the first solution NMR characterization of a tetrahalocation of the heavy pnicogens. The following crystal structures are reported: SbCl(4)(+)Sb(OTeF(5))(6)(-), trigonal system, space group P&thremacr;, a = 10.022(1) ?, c = 18.995(4) ?, V = 1652.3(6) ?(3), D(calc) = 3.652 g cm(-)(3), Z = 2, R(1) = 0.0461; SbBr(4)(+)Sb(OTeF(5))(6)(-), trigonal system, space group P&thremacr;, a = 10.206(1) ?, c = 19.297(3) ?, V = 1740.9(5) ?(3), D(calc) = 3.806 g cm(-)(3), Z = 2, R(1) = 0.0425. The crystal structures of both Sb(OTeF(5))(6)(-) salts are similar and reveal considerably weaker interactions between anion and cation than in previously known SbCl(4)(+) salts. Both cations are undistorted tetrahedra with bond lengths of 2.221(3) ? for SbCl(4)(+) and 2.385(2) ? for SbBr(4)(+). The Raman spectra are consistent with undistorted SbX(4)(+) tetrahedra and have been assigned under T(d)() point symmetry. Trends within groups 15 and 17 are noted among the general valence force constants of the PI(4)(+), AsF(4)(+), AsBr(4)(+), AsI(4)(+), SbCl(4)(+) and SbBr(4)(+) cations, which have been calculated for the first time, and the previously determined force constants for NF(4)(+), NCl(4)(+), PF(4)(+), PCl(4)(+), PBr(4)(+), and AsCl(4)(+), which have been recalculated for the P and As cations in the present study. The SbCl(4)(+) salt is stable in SO(2)ClF solution, whereas the SbBr(4)(+) salt decomposes slowly in SO(2)ClF at room temperature and rapidly in the presence of Br(-) ion and in CH(3)CN solution at low temperatures. The major products of the decompositions are SbBr(2)(+)Sb(OTeF(5))(6)(-), as an adduct with CH(3)CN in CH(3)CN solvent, and Br(2).     

Synthesis and spectral properties of new complexes between glycine and titanium(III), vanadium(III), chromium(III), iron(III), cobalt(II), nickel(II) and copper(II)

Summary Complexes of formula [MCl₃(glyH)₃] (M=Ti, V and Fe) [CrCl₃(glyH)₂H₂O], [MCl₂(glyH)₂(H₂O)₂] (M=Co and Cu) and [NiCl₂(glyH)₃H₂O] have been prepared and characterized by potentiometric curves, chemical analysis, magnetic properties, i.r. and electronic spectral data.     

Monohydrazido(2-)-complexes of molybdenum and tungsten (IV), (V) and (VI)

Summary Reaction of MoCl₅ or WCl₆ with 1-methyl-1-phenylhydrazine or 1, 1-diphenylhydrazine hydrochloride results in the formation of M^VI species [MCl₄(NNRR)]. These react with tertiary phosphines PR₃ to form M^V species [MCl₃(NNRR)(PR₃) _n ] (n=1 or 2).[MoCl₃(NNMePh)(PMe₃)₂] can be reduced in the presence of PMe₃ to the Mo^IV speciescis-mer-[MoCl₂(NNMePh)(PMe₃)₃].     

Bis(tetraethylammonium) tetrabromocobaltate(II) and bis(tetrabutylammonium) tetrabromomanganate(II): structure and magnetic properties

The crystal structures of tetrabromocobaltate(II) and tetrabromomanganate(II) salts of general formula [(C₂H₅)₄N]₂[CoBr₄] (1) and [(C₄H₉)₄N]₂[MnBr₄] (2) were determined. The manganese and cobalt cations are four-coordinated by bromide anions and they adopt a slightly distorted tetrahedral coordination. In the structure of both compounds there are neither hydrogen bonds nor any unusual short-range intermolecular interactions. Magnetic measurements of the powdered samples gave negative values of the Weiss constants equal to −4.9 and −1.1 K for (1) and (2), respectively, which suggest antiferromagnetic interactions to be transferred within the crystal lattice.     

Bis(tetramethylammonium), bis(tetrabutylammonium), and bis(tetraphenylarsonium) dihydrohexaoxoxenonates(VIII)

Bis(tetramethylammonium), bis(tetrabutylammonium), and bis(tetraphenylarsonium) dihydrohexaoxoxenonates(VIII) were obtained in an aqueous solution and in acetonitriie. The rate constants of their decomposition were determined.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 184–185, January, 1995.This work was carried out with financial support from the International Scientific Foundation (Grant REI 000).     

Hexaaquacobalt(II) bis(hypophosphite) and hexaaquacobalt(II)/nickel(II) bis(hypophosphite)

The title compounds, hexa­aqua­cobalt(II) bis­(hypophosphite), [Co(H₂O)₆](H₂­PO₂)₂, and hexa­aqua­cobalt(II)/nickel(II) bis(hypophosphite), [Co_0.5Ni_0.5(H₂O)₆](H₂PO₂)₂, are shown to adopt the same structure as hexa­aqua­magnesium(II) bis­(hypophosphite). The packing of the Co(Ni) and P atoms is the same as in the structure of CaF₂. The Co^II(Ni^II) atoms have a pseudo‐face‐centred cubic cell, with a = b～ 10.3 Å, and the P atoms occupy the tetrahedral cavities. The central metal cation has a slightly distorted octahedral coordination sphere. The geometry of the hypophosphite anion in the structure is very close to ideal, with point symmetry mm2. Each O atom of the hypophosphite anion is hydrogen bonded to three water mol­ecules from different cation complexes, and each H atom of the hypophosphite anion is surrounded by three water mol­ecules from further different cation complexes.     

Single crystal circular and linear dichroism spectra and absolute configuration of M(en)3(NO3)2 (M = Zn(II), Cu(II), Ni(II), Co(II), Mn(II) and Ru(II)

The isomorphous single crystals of M(ethylenediamine)₃(NO₃)₂, where M is Zn(II), Ni(II) and Co(II), exhibit macroscopic optical activity as predicted by their acentric space group. Axial circular dichroism measurements on these pure crystals show conclusively that spontaneous resolution has occurred. The axial circular dichroism and orthoaxial linear dichroism spectra of these pure crystals, and of Cu(II), Ni(II), Co(II), Mn(II) and Ru(II) doped into the Zn(en)₃(NO₃)₂ crystal have been measured at ambient and cryogenic temperatures in the range from 7 to 35 kK. The first NO₃^? transition at 32.5 kK is assigned as ¹A ← ¹A based on its linear polarization and sign of rotational strength. The d-d transitions are assigned in the context of D₃ symmetry and reveal a small negative crystal field parameter k, consistent with theoretical prediction. A positive R for all d-d transitions is found to be associated with the Λ configuration for all of the complex ions, by correlation with the crystal and solution circular dichroism of Ru(en)₃²⁺.     

Acetylsalicylhydroxamic acid and its cobalt(II), nickel(II), copper(II) and zinc(II) complexes

Acetylsalicylhydroxamic acid (AcSHA) was prepared and characterized. Its pK_a value was determined as 7.78. Solid metal complexes of AcSHA were also prepared and characterized by elemental analysis, electronic and i.r. spectroscopies, and by magnetic moment measurements. The shift of both hydroxamic and acetyl carbonyl vibrations to lower frequencies clearly indicates that AcSHA is bonded through oxygen atoms to the metal ions as a tridentate ligand. On the basis of the experimental data, structures for the complexes are purposed.     

Mass spectral behavior of some homoleptic and mixed aryldichalcogenide bis(diphenylphosphino)ferrocenenickel(II), palladium(II), and platinum(II), and bis(diisopropylphosphino)ferrocenepalladium(II) complexes

The mass spectral behavior of a number of organometallic complexes containing the Group 10 metals Ni, Pd, and Pt, together with various thiolate ligands were studied. For Pd, two main types of complexes, differing by the substituents on the phosphorus atom were studied. Types I and II were substituted with bis(diphenylphosphino)ferrocene and bis(diisopropylphosphino)ferrocene ligands, respectively. The Ni complexes, except for one, and the Pd Type I complexes had no molecular radical cations (M(+.)) in their EI spectra. On the other hand, all the Pt complexes showed intense M(+.) ions in their EI spectra indicating that these complexes were more stable as radical cations than those of Ni and Pd. The FAB and MALDI spectra of all the complexes displayed intense quasi-molecular ions (MH(+)) and the fragmentations in both modes were similar. The MALDI spectra of several complexes displayed only M(+.) ions while one gave evidence of both MH(+) and M(+.) ions. Several Pd Type II complexes yielded intense M(+.) in their EI spectra.     

Synthesis,characterization and biological evaluation of manganese(II), cobalt(II), nickel(II), copper(II), and cadmium(II) complexes with monobasic (NO) and neutral (NN) Schiff bases

New complexes of Mn^II, Co^II, Ni^II, Cu^II, and Cd^II with bis(acetophenone) ethylenediamine and 5-chlorosalicylideneaniline or 5-bromosalicylideneaniline have been prepared and characterized on the basis of elemental analyses, thermogravimetric analyses, magnetic measurements, electronic and i.r. spectra. The antimicrobial activities of the complexes, ligands, control (dimethyl formamide) and metal salts were tested against Salmonella typhi (bacteria), Saccharomyces cerevisae (yeast), and two fungal species Lasiodiplodia theobromae and Fusarium oxysporum. The results are discussed.     

Cyclodiphosphazanes with hemilabile ponytails: synthesis, transition metal chemistry (Ru(II), Rh(I), Pd(II), Pt(II)), and crystal and molecular structures of mononuclear (Pd(II), Rh(I)) and bi- and tetranuclear rhodium(I) complexes

Cyclodiphosphazanes having hemilabile ponytails such as cis-[(t)()BuNP(OC(6)H(4)OMe-o)](2) (2), cis-[(t)()BuNP(OCH(2)CH(2)OMe)](2) (3), cis-[(t)BuNP(OCH(2)CH(2)SMe)](2) (4), and cis-[(t)BuNP(OCH(2)CH(2)NMe(2))](2) (5) were synthesized by reacting cis-[(t)()BuNPCl](2) (1) with corresponding nucleophiles. The reaction of 2 with [M(COD)Cl(2)] afforded cis-[MCl(2)(2)(2)] derivatives (M = Pd (6), Pt (7)), whereas, with [Pd(NCPh)(2)Cl(2)], trans-[MCl(2)(2)(2)] (8) was obtained. The reaction of 2 with [Pd(PEt(3))Cl(2)](2), [{Ru(eta(6)-p-cymene)Cl(2)](2), and [M(COD)Cl](2) (M = Rh, Ir) afforded mononuclear complexes of Pd(II) (9), Ru(II) (11), Rh(I) (12), and Ir(I) (13) irrespective of the stoichiometry of the reactants and the reaction condition. In the above complexes the cyclodiphosphazane acts as a monodentate ligand. The reaction of 2 with [PdCl(eta(3)-C(3)H(5))](2) afforded binuclear complex [(PdCl(eta(3)-C(3)H(5)))(2){((t)BuNP(OC(6)H(4)OMe-o))(2)-kappaP}] (10). The reaction of ligand 3 with [Rh(CO)(2)Cl](2) in 1:1 ratio in CH(3)CN under reflux condition afforded tetranuclear rhodium(I) metallamacrocycle (14), whereas the ligands 4 and 5 afforded bischelated binuclear complexes 15 and 16, respectively. The crystal structures of 8, 9, 12, 14, and 16 are reported.     

Fluorophilic properties of (perfluorooctyl)ethyldimethylsilyl substituted and tetramethyl(perfluoroalkyl) substituted cyclopentadienes and their Ti(IV), Rh(III), and Rh(I) complexes

Fluorous partition coefficients in perfluorohexane/toluene system for 37 fluorinated silylcyclopentadienes, titanium(IV) complexes derived from them, perfluoroalkyl substituted tetramethylcyclopentadienes, and their Rh(III) and Rh(I) complexes were determined. Specific fluorophilicity and fluorousness according to Kiss and Rábai were calculated for each compound with the help of molecular volume computed with the Gaussian program. The results show relative unimportance of fluorine content parameter for fluorophilicity as shown by a rhodium(I) complex being fluorophilic at fluorine content as low as 46.3%. As expected, fluorophilicity increased with the fluorous ponytail length and ponytail number in series of similar compounds, whereas polar M-Cl bonds were decreasing it. Fluorophilicities of tetramethyl(perfluoroalkyl)cyclopentadiene tautomers varied considerably despite only small differences in molecular volume being found. Most of the compounds were prepared previously, several new silylcyclopentadienes and titanium(IV) silylcyclopentadienyl complexes are reported here for completion.     

Spectroscopic and thermal investigations of Cu(II), Zn(II), Cd(II), Pb(II) and Al(III) caproates

Five complexes: Cu(cap)₂·4H₂O, Zn(cap)₂, Cd(cap)₂·4H₂O, Pb(cap)₂ and Al(cap)₃·4H₂O (where cap is the caproate anion?=?CH₃(CH₂)₄COO^?) were synthesized and characterized by elemental analysis, IR-spectroscopy, thermogravimetric analysis (TG), differential thermal analysis (DTA), UV-Vis spectra, ¹H NMR and X-ray powder diffraction (XRD). Using the non-isothermal, Horowitz-Metzger (HM) and Coats-Redfern methods, the kinetic parameters for the non-isothermal degradation of the complexes were calculated using TG data. The infrared and ¹H NMR data are in agreement with coordination through carboxylate, with cap acting as a bridging bidentate ligand. Thermogravimetric analysis of the hydrated complexes shows that the first degradation step is release of water molecules followed by decomposition of the anhydrous complexes, with release of caproate molecules.     

Hydrogen diffusion on (100), (111), (110) and (211) gold faces

Calculations showed that hydrogen adsorption into subsurface sites is most likely to occur on Au (110) and (211) faces. The presence of low-coordinated Au atoms on significantly reduces the barrier of subsurface adsorption of H. The barriers of H surface diffusion increase in the following Au series: (110) < (111) < (100) < (211). An analysis of the dependence of the surface diffusion barriers on the electronic structure of gold atoms on the respective faces revealed a U-shaped dependence of the centers of the s- and d-bands. This dependence is the result of the filling of the s- and d-bands on different faces of the gold. The results obtained suggest that it is possible to use band centers to determine surface diffusion barriers.     

Syntheses and vibrational spectra of xenon(VI) fluorozirconate(IV) and xenon(VI) fluorohafnate(IV)

Liquid xenon difluoride at 140°C does not react with zirconium or hafnium tetrafluorides, neither does liquid xenon hexafluoride at 60°C. Therefore reactions between the corresponding hydrazinium fluorometalates or ammonium fluorometalates and xenon difluoride and xenon hexafluoride, respectively, were carried out. N₂H₆ZrF₆ and N₂H₆HfF₆ react with xenon difluoride at 60°C again yielding only the corresponding tetrafluorides, while the analogous reaction with (NH₄)₂ZrF₆ and (NH₄)₂HfF₆ proceeds at 170°C yielding the corresponding ammonium pentafluorometalates, which are stable and do not react further with excessive xenon difluoride up to 200°C.The reaction between N₂H₆ZrF₆ or N₂H₆HfF₆ and xenon hexafluoride proceeds at room temperature yielding a series of thermally unstable compounds of the type mXeF₆.MF₄ (M = Zr, Hf) where m ? 6. The final products which are stable at room temperature are XeF₆.MF₄ (M = Zr,Hf). Spectroscopic evidence suggests that these compounds are salts of a XeF⁺₅ cation squashed between a polymeric anion of the type (MF₅)^x-_x.     

Dialkylphosphonate and Thiophosphonate (Open Chain and Cyclic) Derivatives of Arsenic(III) and Tin(IV)

Abstract

Dialkylphosphonates¹ and -thiophosphonates² are versatile ligands but except for a few brief reports^3–9 the chemistry of their derivatives with group IV and V elements remains unexplored. The corresponding derivatives of cyclic phosphonates and thiophos-phonates¹⁰ are virtually unknown.     

Heterometallic complexes of titanium(IV) and tin(IV) chlorides with nickel(II) and cobalt(II) enaminoketonates and enaminoiminates

Heterometallic complexes have been synthesized by the interaction of Ti^IV and Sn^IV chlorides with Ni^II and Co^II enaminoketonates and enaminoiminates. The complexes were characterized by elemental analyses, magnetic susceptibility and i.r. spectroscopy. The catalytic properties of the complexes in the preparation of linear low density polyethylene have been studied. TMC 2192