Volume 53, Issue 2

The crystal structure of MgSO 3 ·H 2 O , space group P2 1 /ln, Z = 4, D x = 2.415 g·cm -3 , a = 4.699(1), b = 12.751(3), c = 5.618(1) Å, β = 90.49(3)°, was determined by single crystal X-ray diffraction. MgSO 3 ·H 2 O crystallizes in the MnSO 3 ·H 2 O type. The structure consists of buckled trans layers ∞ [MgSO 3 ·H 2 O], which are built up from strongly distorted MgO 5 (H 2 O) octahedra sharing four equatorial vertices, and of trigonal pyramidal SO 3 2- ions. It is close­ly related to the structures of orthorhombic MnSeO 3 ·D 2 O and monoclinic ZnSeO 3 ·H 2 O . The Mg-O distances range from 2.051(3) to 2.175(4) Å. The S-O distances (1.543(3), 1.547(3) and 1.493(3) Å) and the O-S-O angles (98.4(2) and 2x 106.0(2)°) correspond to those in MnSO 3 ·H 2 O . The distortion of the MO 5 (H 2 O) octahedra (M = Mg, Mn) and of the SO 3 2- ions is smaller in MgSO 3 ·H 2 O , but with greater deviations from m symmetry. The distances between the H-connected ∞ 2 [MSO 3 ·H 2 O] layers are greater in MgSO 3 ·H 2 O , indicating weaker inter-layer hydrogen bonds. The lateral arrangement of the ∞ 2 [MSO 3 ·H 2 O] layers is nearly the same in both sulfite monohydrates.

The first synthesis of spirocyclic tetrasulfonamidosilanes is described. According to the X-Ray structure analysis of the most stable tetratosylamidosilane obtained the Silicon is bonded to four Nitrogen atoms in a spirocycle and surrounded by four Oxygen atoms which are located above the planes of the SiN 4 tetrahedron.

Single crystals of LaTi(Ti 0.25 Te 0.75 )O 6 have been prepared by solid state reactions. X-ray investigations led to trigonal symmetry, space group C 3 1 -P3 , a = 5.141(10), c = 5.218(10) Å, Z = 1. The compound is characterized by a predominantly ordered distribution of Ti 4+ and Te 6+ . Typical features of the crystal structure are staggered layers containing edge connected TiO 6 and (Ti,Te)O 6 octahedra. The layers are connected by La 3+ ions receiving an octahedral coordination by the surrounding oxygen ions. The relationships to the PbSb 2 O 6 type and the recently described compound Sr(MnTe)O 6 are discussed.

The reaction of the transition metal complexes CpV(CO) 4 and [CpMo(CO) 3 ] 2 with thionyl chloride affords the oxodichlorides CpM(O)Cl 2 (M = V, Mo) by oxidative decarbonylation. The X-ray structure analysis of CpV (O)Cl 2 shows the pseudo tetrahedral “piano-stool” configuration for the central vanadium atom.

Single crystals of Ag 2 Cs[B 15 O 24 ] were prepared by using a B 2 O 3 flux technique with Ag 2 CO 3 and Cs 2 CO 3 in a closed silver tube at 650 °C. X-Ray investigations led to a new crystal structure in the space group P 2 1 2 1 2 (Nr. 18) with lattice parameters a = 1778.7 (4); b = 2219.2 (4); c = 512.2 (1) pm, Z = 4. The silver atoms are part of distorted AgO 4 tetrahedra and planar AgO 3 units while the caesium atoms are eightfold coordinated by oxygen. The compound contains an as yet unknown borate anion [B 15 O 24 ] with twelve BO 3- and three BO 4 units per formula. The BO 3 units are connected to eight cords twisted to helices which are combined via BO 4 tetrahedra to a three dimensional framework with large tunnels occupied by the cations.

A new fullerene co-crystal C 60 *SiH(C 6 H 5 ) 3 has been synthesized by crystallisation from a melt of SiH(C 6 H 5 ) 3 and C 60 in sealed duran tubes at 80°C. X-ray investigations led to triclinic symmetry, space group P1̄, a = 10.086(1), b = 14.431(2), c = 14.911(2) Å, α = 79.13(1), β = 74.943(9), γ = 88.33(1)°, V = 2058.0(4) Å 3 , Z = 2. The crystal structure consists of isolated fullerene and silane molecules. At -80°C, C 60 is still rotationally disordered. Temperature dependent Guinier powder diagrams do not show any phase transformation between 25 and -165°C. The compound is stable in air.

Crystals of the title compounds were grown under hydrothermal conditions. The crystal structures were determined by single crystal data. NaFe[BP 2 O 7 (OH) 3 ] (monoclinic, C 2/c, a = 1042.0(2), b = 821.5(1), c = 921.7(1) pm, β = 116.60(1)°, Z=4): The crystal structure contains isolated anions [BP 2 O 7 (OH) 3 ] 4- , which correspond to trinuclear units PO 1/2 O 3 -BO 2/2 (OH) 2 -PO 1/2 O 2 (OH) of corner sharing tetrahedra. Fe 3+ is coordinated octahedrally by oxygen, Na + is 8 -fold coordinated by oxygen forming cubes. K 2 Fe 2 [B 2 P 4 O 16 (OH) 2 ] (triclinic, P1̄, a = 516.7(1), b = 808.9(1), c = 834.0(1) pm, α = 87.06(f), β = 80.21(1), γ = 86.59(1)°, Z = 1): The crystal structure contains isolated anions [B 2 P 4 O 16 (OH) 2 ] 8- . Four-membered rings of tetrahedra with two additional terminal phosphate groups are formed by condensation of two trinuclear units P O 1/2 O 3 -BO 3/2 (OH) -PO 2/2 O 2 . Fe 3+ is in an octahedral and K + in an irregularly 10-fold coordination by oxygen.

The reaction of [(Ph 3 As)AuCl] with Ag 2 O in the presence of NaBF 4 in tetrahydrofuran affords three products, identified as [(Ph 3 As) 4 Au]BF 4 (40.3%), [(Ph 3 As) 2 Au]BF 4 (16.4%) and {[(Ph 3 As)Au] 3 O}BF 4 (17.3%). The properties of the main product agree well with recent literature data. The other two compounds are new and have been identified by their analytical, spectroscopic, and crystallographic data. The structures are isomorphous with those of the analogous Ph 3 P complexes. Variations in the stabilities are discussed in terms of kinetic and thermodynamic effects.

The thermodynamical data of ammonium neodymium chlorides (NH 4 ) 2 NdCl 5 and NH 4 Nd 2 Cl 7 were derived by the determination of their decomposition equilibria by total pres­sure measurements. Moreover, solution calorimetry was applied. The enthalpies of formation of these phases were calculated from their heats of solution and from the enthalpies of formation and the heats of solution of NdCl 3 and NH 4 Cl. Data by total pressure measurement: ΔH° B ((NH 4 ) 2 NdCl 5,f,298 ) = - 412,5 ± 3,6 kcal/mol; S°((NH 4 ) 2 NdCl 5 f 298 ) = 80,1 ± 5,8 cal/K · mol; ΔH° B (NH 4 Nd 2 Cl 7,f,298 ) = -579,5 ± 3,5 kcal/mol; S°(NH 4 Nd 2 Cl 7,f,298 ) 101,8 ± 5,6 cal/K mol. Data by solution calorimetry: ΔH° B (NdCl 3,f,298 ) = -251,2 ± 0,7 kcal/mol; ΔH° B ((NH 4 ) 2 NdCl 5,f,298 ) = -405,5 ± 1,0 kcal/mol; ΔH° B (NH 4 Nd 2 Cl 7,f, 298 ) = -576,8 ± 1,7 kcal/mol.

Synthesis and single crystal growth by chemical transport reactions of rhenium and rhenium oxides is reported. Several transport agents like the mercury halides HgCl 2 , HgBr 2 , HgI 2 , tellurium tetrachloride and iodine have been employed the transport of the rhenium compounds. Mass spectrometric experiments gave informations about the composition of the gas phase. The transport reactions were traced by calculations based on the knowledge of the gas phase species and their thermodynamical data.

The reactions of Schiff bases from benzophenone and α-amino acid and peptide esters with tetrachloropalladate afford the chloro bridged ortho palladated complexes 1-8 and 11-18. The chloro bridges are cleaved by P and N donors (PR 3 , pyridine, α-amino acid ester) to give the monomeric complexes 19-35. From 1, 2, 3 and bidendate ligands (dppe, α-amino carboxylates, cysteine methyl ester) the bis(chelates) 36-41, with N-diphenylmethylene glycylglycine ester the C,N,N chelates 46 and 47 are obtained. The complexes 14, 23 and 47 were characterized by X-ray diffraction. Due to the two neighbouring five membered chelate rings in 47 a considerable distortion from the square planar coordination is observed.

X-ray structure determinations have been performed on single crystals of trans-(Ph 4 P) 2- [B 6 H 4 I 2 ] (1) (triclinic, space group P1̄, a = 9.9680(12), b = 10.9690(11), c = 11.0470(14) Å,α = 88.167(9), β = 80.466(12), γ = 68.839(11)°, Z = 1), mer-(Ph 4 P) 2 [B 6 H 3 I 3 ] · 2 CH 2 Cl 2 (2)(triclinic, space group P1̄, a = 11.8694(11), b = 15.1699(13), c = 17.051(2) Å, α = 75.118(9), β = 71.953(10), γ = 69.331(8)°, Z = 2), trans-(Ph 4 P ) 2 [B 6 H 2 I 4 ] · 2 CH 3 CN (3) (monoclinic, space group P2 1 /n, a = 14.9665(10), b = 7.6783(10), c = 23.385(3) Å, β = 95.78(9)°, Z = 2), and (CH 2 Py 2 )[B 6 HI 5 ] (4) (orthorhombic, space group Pnma, a = 13.660(2), b = 11.8711(13), c = 13.839(2) Å, Z = 4). The B 6 octahedra are compressed in the direction of the B-I bonds, resulting in shortened diagonal B ··· B distances with average values of the groups I-B ··· B-I = 2.37 and I-B ··· B-H = 2.43 Å as compared with H-B ··· B-H = 2.49 Å.

3,4-Bis{[2-(methyl-phenyl-oxophosphanyl)-ethyl]phenyl-phosphanyl}pyrrolidines have be­en synthesized by Michael Addition from the corresponding methyl-phenyl-vinyl-phosphane oxides and 3,4-bis(phenylphosphino)pyrrolidines. For purification of the ligands palladium complexes were used and with the enantiomerically pure ligands Rh complexes have been pre­pared. The catalyst has 6 stereogenic centers. In the hydrogenation of Z-α-acetamidocinnamic acid all six stereogenic centers have an influence on the enantioselectivity. The influence is strongest from the C stereocenters of the pyrrolidine ring. Less important are the stereogenic centers on the coordinated P atoms. The influence of the stereocenters on the non-coordinated P = O groups is the least, but it is not negligible. The ee values obtained with the ligands containing P = O groups are much lower than those obtained with ligands which are substituted only with aryl groups. Ketones are hydrogenated with only low ee’s.

The electronic spectrum of Cp 2 TiS 5 shows a long-wavelength absorption at λ max = 492 nm which is assigned to the lowest-energy S 5 2- → Ti IV ligand-to-metal charge transfer (LMCT) transition. The photolysis of the complex in CH 2 CI 2 leads to the formation of Cp 2 TiCl 2 and elemental sulfur. It is suggested that LMCT excitation initiates a reductive elimination with the extrusion of S 5 while the reduced titanocene is reoxidized by the solvent.

In the reaction of K 2 [OsX 3 Y 3 ] with boiling water/acetylacetone (1:1) the six mixed com­plexes cis-and trans-[OsX 2 (acac) 2 ] (X ≠ Y = Cl, Br, I) are formed, which have been purified by column chromatography with toluene on silica gel. The IR and Raman spectra (10K) show the intraligand vibrations of the acac groups with nearly constant frequencies and the stretching vibrations of OsO in the range 460-696, of OsCl at 315-345, of OsBr at 210-225, and of Osl at 160-175 cm -1 . A normal coordinate analysis based on a modified valence force field was performed for trans-[OsClBr(acac) 2 ] and the vibrational modes have been assigned. With a set of 32 force constants, taking into account the intraligand vibrations, a good agreement between observed and calculated frequencies has been achieved. The valence force constants are f d (OsCl • ) = 1.75, f d (OsBr′) = 1.63 and f d (OsO) = 3.27 mdyn/Å.

In the reaction of K 2 [OsCl 6 ] with boiling water/acetylacetone (1:1) a mixture of different chloro-acetylacetonato complexes is formed, from which [Os(acac) 3 ] can be isolated by column chromatography with dichloromethane on silica gel. The crystal structure of [Os(acac) 3 ] (mo­noclinic, space group P2 1 /c,a = 13.968(5), b = 7.517(5), c = 16.455(5) Å ,β = 98.939(5)°, Z = 4) has been determined by single crystal X-ray diffraction analysis. High resolution IR and Raman spectra were measured at low temperature (10K). Based on the molecular parameters of the X-ray structure determination a normal coordinate analysis has been performed and the normal modes of vibration have been assigned. With a set of 32 force constants, taking into account the intraligand vibrations, a good agreement between observed and calculated frequencies has been achieved. The valence force constants are f d (OsO) = 3.19 and f d (OC) = 6.74 mdyn/Å.

The title compound has been synthesized as a green solid by the reaction of MeCl 2 SiNHSiMe 3 and Ti(NMe 2 ) 4 in CH 2 Cl 2 . The crystal structure was determined by single crystal X-ray methods at room temperature (C2/c, a = 1825,7(4), b = 909,9(2), c = 1116,1(2) pm, β = 125,09(3)°, Z = 4,R1= 0,047, wR2 = 0,147) to be an ionic salt [H 2 NMe 2 ] + [(Me 2 NH) 2 TiCl 4 ] - . The central titanium(III) atom of the anion is bound to four Cl atoms and weakly coordinated by two Me 2 NH ligands.

The melting diagrams of the binary systems 18-crown-6/formic acid and 18-crown-6/acetic acid have been set up and the crystal structures of the adducts 18C6 · 2 HCOOH (1, space group P 2 1 /c with Z = 2 formula units per unit cell) and 18C6 · 2 CH 3 COOH (2, C2/m, Z = 2) determined. Furthermore three ternary phases, 18C6 · CH 3 COOH · H 2 O (3, P2 1 /c, Z = 4) and dimorphic 18C6 · 2 CH 3 COOH · 4 H 2 O (high temperature form 4, P2 1 /n, Z = 2; low temperature form 5, P2 1 /n, Z = 2) have been characterized in the same way. In each structure the crown ether molecule has the (pseudo) D 3d conformation common for many of its complexes. Various aspects of the intermolecular hydrogen bonding are described.

(Na, K)NO 3 melts of various ratios were used as promoters for the partial oxidation of methane to methanol. Experiments were performed in a flow reactor system under atmo­spheric pressure and at various temperatures in the range of 525-600 °C. The influence of reaction temperature, melt composition, and reduced oxygen species on methane conversion and methanol selectivity were investigated systematically. The major reaction products were CH 3 OH, CO, CO 2 , and trace amounts of C 2 H 6 and C 2 H 4 . A methane conversion of 1.8-12.4% and a methanol selectivity of 0.4-14.1% were obtained under these reaction condi­tions. Binary melts could achieve higher methanol selectivity than a single melt. The amounts of reduced oxygen species O 2 - and O 2 2- were estimated from thermochemical data according to the ion equilibrium in molten nitrates. The promotive effect of nitrate melts was confirmed and the results indicate that superoxide O 2 - plays an important role for methanol formation.

The interaction of VO 2+ with L-ascorbic acid and dehydroascorbic acid was investigated by electronic spectroscopy in solution at different pH values. In the case of ascorbic acid, two different solid complexes containing one or two monodeprotonated ascorbate ligands could be isolated and characterized. With dehydroascorbic acid, interaction begins at pH = 4 but at higher pH values the ligand is hydrolysed irreversibly, generating 2,3-diketogulonic acid. A solid complex containing this ligand could be precipitated at pH = 7. Its spectroscopic behavior confirms the interaction of the cation with an enolised form of the acid.

The new compound [Cs(18-crown-6)]ICl 2 has been prepared by the reaction of cesium chloride and 18-crown-6 with iodine chloride in ethanol and structurally characterized by X-ray diffrac­tion methods. The geometries of the cation [Cs(18-crown-6)] + and of the anion ICl 2 - are as expected.