Volume 52, Issue 10

Mixed crystals V 1−X Nb X O 2 exist about the whole area of quasibinary line VO 2 -NbO 2 . The phase relations between these compositions VO 2 -NbO2 and the binary and ternary phases of the described subsystems were cleared using chemical transport reactions (CTR) and solid state reactions. A more precise phase diagram of the ternary system V/Nb/O is given for the temperature range of 900 - 1000°C.

By reaction of (n-Bu 4 N) 2 [B 12 H 12 ] with 2,2′-bipyridine at 190 °C the 2,2′-bipyridyl-undecahydro- closo-dodecaborate anion [(2,2′-C 10 H 8 N 2 )B 12 H 11 ] − is formed which can be seperated from excess [B 12 H 12 ] 2− by ion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The X-ray structure determination of (Ph 4 As)[(2, 2′-C 10 H 8 N 2 )B 12 H 11 ] (monoclinic, space group P2 1 /c with a = 13.3190(9), b = 10.1532(14), c = 28.788(3′) Å, β = 96.761(7)°, Z = 4) reveals that the bipyridyl substituent is bonded via one nitrogen atom. The 11 B NMR spectrum exhibits a 1:5:5:1 pattern with ipso-B1 at -0.3, B2-B6 at -14.5, B7-B11 at -15.3 and antipodal-B12 at -15.9 ppm. The 13 C and 1 H NMR spectra show the characteristic patterns of the bipyridyl group in the range of 124.5 to 158.6 ( 13 C) and 7.4 to 9.6 ppm ( 1 H) respectively. The IR and Raman spectra exhibit characteristic BH stretching vibrations between 2445 and 2568 cm -1 and the stretching of the CC and CN bonds in the range of 1427 to 1619 cm -1 .

The phase diagram of the ternary system Ca/Mo/O has been determined. Powder samples of the ternary compounds CaMoO 4 , CaMoO 3 , CaMo 5 O 8 , Ca 16.5 Mo 13.5 O 40 and Ca 5.45 Mo 18 O 32 were prepared by solid state reactions. Rietveld analysis based on powder X-ray diffraction data shows that the compound CaMo 5 O 8 has monoclinic structure (P2 1 /c) with a = 7.549, b = 9.064, c = 9.974 Å, β = 110.04°. CaMo 5 O 8 , Ca 16.5 Mo 13.5 O 40 and Ca 5.45 Mo 18 O 32 are semiconductors over the temperature range 75 to 300 K.

Tris(diethylamino)benzylphosphonium bromide, [(C 2 H 5 ) 2 N] 3 PCH 2 C 6 H 5 + Br − · CH 3 CN (1), has been prepared by the reaction of tris(diethylamino)phosphine with benzylbromide in acetonitrile and its structure determined. The colorless crystals are monoclinic, space group P2 1 /n, Z = 4, a = 954.5(11), b = 2552(3), c = 1017.9(9) pm, β = 92.27(8)°. The lattic contains Br − anions and [(C 2 H 5 ) 2 N] 3 PCH 2 C 6 H 5 + cations. [(C 2 H 5 ) 2 N] 3 PCH 2 C 6 H 5 ] + Br 3 − (2) has been obtained by treating compound 1 with equimolar quantities of elemental bromine in acetonitrile solution. The yellow-red crystals of 2 are monoclinic, space group P2 1 /n, Z = 4, a = 1065.1(4), b = 1952.9(2), c = 1201.7(2) pm, β = 98.18(2)°, and comprise [(C 2 H 5 ) 2 N] 3 PCH 2 C 6 H 5 + cations and linear Br 3 − anions.

Tri(tert-butyl)plumbyl-amine 1 was prepared and studied by one- (1D) and two-dimensional (2D) 1 H, 13 C, 15 N and 207 Pb NMR which allowed determination of the coupling signs 1 J( 207 Pb, 13 C) (> 0), 2 J( 207 Pb, 13 C) (> 0), 1 J( 207 Pb, 15 N) (> 0; reduced coupling constant 1 K( 207 Pb, I5 N) < 0) and 2 J( 207 Pb-N- 1 H) (< 0). Transamination of 1 with aniline and pyrazole afforded the corresponding aniline (2) and pyrazole derivatives (3), respectively. N-Lithiation of 1, followed by treatment with Me 3 SiCl gave the tri(tert-butyl)plumbyl-trimethylsilyl-amine 5. The multinuclear magnetic resonance data of 2, 3 and 5 are presented. Trimethylplumbylphenyl- amine and trimethylplumbyl-tert-butyl(dimethyl)silyl-amine were prepared and their NMR data were measured for comparison.

In the reaction of cacodylic acid (CH 3 ) 2 AsOOH in the superacid system HF / MF 5 (M = As, Sb) the difluorodimethylarsonium hexafluorometallates [(CH 3 ) 2 AsF 2 ]MF 6 are formed and have been characterized by i.r. and Raman spectroscopy. The crystal structure of the hexafluoroantimonate has been determined at -100°C (orthorhombic space group Ibca with Z = 4, a = 10.973, b = 11.164, c = 14.200 pm).

ICN reacts under oxidative addition with excess ClONO 2 to yield NCI(ONO 2 ) 2 , which has been characterized by its vibrational spectra. ClCN and BrCN do not react with ClONO 2 .

A new dioxouranium(VI) nitrate complex with N,N′-tetraethyl-N″-trichloracetylphosphortriamide (HL = CCl 3 C(O)N(H)P(O)(NEt 2 ) 2 ) of composition UO 2 (HL) 2 (NO 3 ) 2 (1) has been synthesised. The IR spectroscopic data reveal that the ambidentate ligand is coordinated to the metal center in a monodentate manner via the phosphoryl oxygen atom. The crystal and molecular structure of 1 has been determined from X-ray diffraction data (triclinic, space group P1̄ with a = 9.225(2), b = 10.360(2), c = 12.249(2) Å, α = 100.02 (1), β = 103.81(1), γ = 108.80 (1)°, Z = 1; R = 0.037 for 4092 unique reflections. The structure is made up of centrosymmetric molecules in which the neutral ligands HL are monocoordinated. Phosphoryl and carbonyl groups of the HL moieties are in the trans positions to each other. The axial vertices of the distorted hexagonal bipyramid of uranium are occupied by two oxo ligands [U-O 1.753(5) Å] while six oxygen atoms of phosphoryl and nitrate groups lie in the equatorial plane [U-O 2.347(5)-2.547(6)Å],

The reactions of Na 2 PdCl 4 , [(nBu 3 P)PtCl 2 ] 2 , [(nBu 3 P)PdCl 2 ] 2 and [(C 8 H 14 ) 2 RhCl] 2 /CO with diphenylmethylene glycine esters (L 1 ) or 2-phenyl-4-R-oxazolones (L 2 ) afford the complexes (nBu 3 P)(Cl) 2 Pt(L 1 ), (OC) 2 (Cl)Rh(L 1 ), Cl 2 Pd(L 1 ) 2 and (nBu 3 P)(Cl) 2 M(L 2 ) (M = Pd, Pt), respectively. The X-ray structural determination of Cl 2 Pd(L 1 ) 2 and the 1 H and 13 C NMR spectra show a close proximity of the ortho phenyl-H-atom to the metal; the complexes are precursors for ortho metallation.

The amido complexes L 2 M(Cl)N(Boc) 2 (M = Pd, Pt; L = PPh 3 , PnBu 3 , PEt 3 ; 2 L = COD) and Ph 3 PAuNBoc 2 were prepared from Na + N(CO 2 tBu) 2 − and L 2 MCl 2 or Ph 3 PAuNO 3 , respectively. The structure of cis-(Ph 3 P) 2 Pt(Cl)NBoc 2 was determined by X-ray diffraction.

Aniline tricarbonyl chromium complexes η 6 -C 6 H 4 (R)NHR 1 )Cr(CO) 3 (R = H, CH 3 ; R 1 = H, CH 3 ) are added to [(OC) 5 Re(η 2 -C 2 H 4 )] + and [(η 5 -C 5 H 5 )Fe(CO) 2 (η 2 -C 2 H 4 )] + to give the heterobimetallic ligand bridged complexes (OC) 3 Cr(η 6 -C 6 H 4 (R)N(R 1 )C 2 H 4 -η 1 )Re(CO) 5 and (OC) 3 Cr(η 6 -C 6 H 4 (R)N(R 1 )C 2 H 4 -η 1 )Fe(CO) 2 (η 5 -C 5 H 5 ). The structure of (OC) 3 Cr(η 6 - C 6 H 4 (CH 3 )N(H)C 2 H 4 -η 1 )Re(CO) 5 was determined by X-ray diffraction analysis.

Single crystals of Pb 2 In 2 Si 2 O 9 have been prepared by crystallisation from melts of Pb(NO 3 ) 2 , ln 2 O 3 and SiO 2 . The compound crystallizes with orthorhombic symmetry, space group C 2v 9 - Pna2 1 with the lattice constants a = 10.529(1), b = 11.372(1) and c = 7.019(3) Å, Z = 4. Despite the fact that the Kentrolite/Melanotekite structure is characterized by dissimilar occupied split positions of lead, Pb 2 In 2 Si 2 O 9 shows completely filled and ordered point positions. The location of a dot like lone pair of Pb 2+ is estimated by Coulomb term calculations of lattice energy. The results are discussed with respect to published Pb-lone pair distances using the electronic polarizability coefficient of the lone pair cation or simple geometrical considerations.

The following compounds were prepared by cocrystallization of their components from MeOH or MeCN and structurally characterized by low-temperature X-ray diffraction: Na[N(SO 2 Me) 2 ]·HN(SO 2 Me) 2 ·2 (12-crown-4) (2, orthorhombic, space group Pna2 1 ). Na[N(SO 2 Me)·HN(SO 2 Me)·(15-crown-5) (3, monoclinic. P2 1 /n), Na[N(SO 2 Ph) 2 ] · HN(SO 2 Ph) 2 · 2 (12-crown-4) (4. monoclinic. P2 1 ). (MeNH) 2 COHN(SO 2 Ph) 2 ·0.5 MeCN (5, monoclinic. P2 1 /n). The four structures exhibit [(RSO 2 ) 2 N-H ··· N(SO 2 R) 2 ] - anions as rare examples of intermolecular [N-H ···N] - homo- conjugates. The N ··· N distances of the asymmetric hydrogen bonds are. in order. 266.9(6). 276.0(3). 291.3(4) and 279.4(2) pm. the corresponding N-H···N angles amounting to 137(10), 176(3), 177(4) and 177(2)°. The asymmetry of the hydrogen bonds is clearly reflected in the geometry of the NS 2 groups (amine moieties: N-S 162.3-165.2 pm. S-N-S 124.5-127.1°; amide moieties: N-S 159.7-161.8 pm. S-N-S 119.1-122.6°). The dihedral angles formed by the NS 2 planes vary from 51.8° in 4 to 87.6° in 5. The crystal lattices of 2 and 4 consist of discrete ions, sandwich-type [Na(12-crown-4) 2 ] + complexes acting as the counter-ions. In 3. Na + is coordinated in an out-of-cavity pattern by the five polyether oxygen atoms and further accepts two Na-O bonds from the amide moiety of the complex anion [Na-O(crown) 241.5(2)-249.9(2), Na-O(anion) 235.0(2) and 263.9(2) pm]. Thе surprising structure of 5 contains homoconjugated 1.3-dimethylurea cations [(MeNH) 2 C-O-H ··· O=C(NHMe) 2 ] + , which are formed via a very strong asymmetric [O-H ···O] + hydrogen bond [О···О 247.7(2) pm. O-H ··· O 172(3)°] and are associated with the amide moieties of the anions through a set of N-H···О bonds to form infinite chains: the MeCN molecules occupy lattice cavities.

The complex compounds 4HN (SO 2 Me) 2 · (diaza-18-crown-6) (1) and Na[N(SO 2 Ph) 2 ] · 2HN(SO 2 Ph) 2 · 2 (12-crown-4) · 2 MeOH (2) were obtained from their components and characterized by low-temperature X-ray diffraction. Structure 1 (monoclinic, space group P2 1 /n) displays centrosymmetric formula units consisting of a biangular diazonia-18-crown-6 dication, two (MeSO 2 ) 2 N − anions situated above and below the macrocycle and linked to the NH 2 + groups via an N - H ··· O and N -H ··· N bond system, and finally two HN(SO 2 Me) 2 molecules, each forming an N -H ··· O bond to one of the anions. The molecule-anion entity represents an iso form of the [(RSO 2 ) 2 N -H ··· N (SO 2 R) 2 ] − homoconjugates previously described. The crystal packing of 1 is stabilized by an extensive and highly organized [H 2 C -H ··· O(S)] hydrogen bond network. Structure 2 (monoclinic, space group P2 1 /n) exhibits inconspicuous [Na(12-crown-4) 2 ] + cations and, as a striking feature, supramolecular anions assembled from a central (PhSO 2 ) 2 N − ion, two MeOH molecules flanking the amide anion, and two HN (SO 2 Ph) 2 molecules bonded to the MeOH moieties. The assembly is held together by two N -H ··· O(H )(Me) bonds, one MeO -H ··· N − bond and one MeO -H ··· O(anion) interaction. For both structures, conformational peculiarities of the N(SO 2 C) 2 groups are discussed.

The key step is to prepare rare gibberellins by converting the more readily available gibberellins (GA 3 , GA 4 , GA 7 and GA 13 ) into their m ethyl esters. The DMFDMA is employed as an esterifying reagent to avoid the diazom ethane due to its toxic, explosive and hazardous nature. It is observed that DMFDMA apart from esterification can also be used as acetylating and epimerizing reagent.

The reactions between bisimidoyl chlorides of oxalic acid 1 and different thioamides derived from CH-acidic methylene compounds 2, 7 as well as thiobiuretes 9-11 were investigated. The hitherto unknown cyclic keten-N,S-acetals 3 with an oxalic acid substructure were mainly formed by an ambidoselective cycloacylation reaction. Comparison of 13 C NMR data suggests a thiazolidine structure with three exocyclic doubly bound residues. In the case of compound 3 g the exact configuration (Z) was determinated on the basis of a heteronuclear Overhauser experiment.

The functionalization reactions of 2,2’-bisindolyls with electrophiles and dienophiles gave rise to a group of new protein kinase C inhibitors. Rationalization of structure activity relationships and of some mechanistical aspects concerning the synthesis X ray crystal structures are described for 2,2’-bisindolyl derivatives 1-3 and 6 and for indolo[a]carbazoles 4 and 5.

The structures and protonation energies of aminoguanidine and aminoguanidinium ion were obtained from quantum chemical calculations by using the density functional method B3-LYP and the standard basis set 6 -31 G(d ). The energy differences between the various forms of the two possible tautomers, the endiamine and the imidamide form, were investigated. The endiamine was found to be more stable than the most stable form of the imidamide by 5 kcal/mol in the gas phase. The proton affinity of am inoguanidine was found to be 241.4 kcal/mol (B3 -LYP/6 -31 G(d )) in the gas phase. The liquidation pK a2 for amininoguanidine and the guanidinium ion was determined to be 11.5 ± 0.1. The reference values for guanidine free base and the guanidinium ion are 235.7 kcal/mol and 13.6, respectively. The difference in the order of basicity in the gas phase and in aqueous solution between aminoguanidine and guanidine is discussed in terms of symmetry, resonance, delocalisation, rehybridisation of nitrogen atoms, and electrostatic repulsion.

Complexes of yttrium (III) and lanthanide(III) ions with an axial macrobicycle derived from the 2+3 Schiff-base condensation of tris(2-aminoethyl)amine with 2,6-diformylpyridine have been prepared in high yields using a one-step procedure. The complexes, with formula [M 2 L](NO 3 ) 6 · xH 2 O · ySolv, (M = Y, La - Lu, except Pm) and [M 2 L](ClO 4 ) 6 · xH 2 O · ySolv, (M = La - Er, except Pm ), have been characterised by elemental analysis, molar conductivity, mass, IR and 1 H NMR spectroscopy.

The reaction of bis(triphenylstannyl)sulfur diimide 1 with water in CH 2 Cl 2 provides an alternative route to bis(triphenylstannyl)sulfite 2, affording crystalline material suitable for X-ray structural analysis (monoclinic, space group P2 1 /n). The sulfite 2 is monomeric in solution but forms polymeric chains in the solid state with both tetra- and penta-coordinate tin atoms.

In attempts to incorporate the L i(I) cation into the C a(II) positions of the fluoroapatite lattice it has been shown that the unit cell becomes increasingly distorted with the increase of lithium concentration. Crystallographic data have been obtained from X-ray powder data. The infrared spectra of these substituted apatites show that the Li(I) incorporation has a negligible effect on the strength of the P-O bonds.

The crystal structure of acetate acidium hexafluoroantimonate CH 3 C(OH) 2 + SbF 6 − has been determined on single crystals with MoKα radiation at -83 °C. The structure is triclinic, space group P1̄, Z = 2, and the cell dimensions are a = 604.7(1), b = 692.3(3), c = 951.7(2) pm, α = 102.13(2)°, β = 106.53(2)°, γ = 99.27(2)°. In the CH 3 C(OH) 2 + cation the C-C distance is 147.8(6) pm , the C -O distances are 125.1(6) and 129.1(5) pm. The SbF 6 − anion is slightly distorted octahedral.

The cyclo-phosphazenium bromide [(Ph 2 PC 2 H 4 PPh 2 )N ]Br has been prepared by the reaction of bromine with Ph 2 PC 2 H 4 PPh 2 NSiMe 3 and subsequent elimination of BrSiMe 3 in boiling acetonitrile. According to a crystal structure d e termination the com pound contains bromide ions and cations with a P 2 C 2 N heterocycle in a twist conformation with PN bond lengths of 160.6(3) and 161.5(3) pm. Space group Pna2 1 , Z = 4, lattice dimensions at - 70 °C: a = 1702.5(3), b = 1280.8(3), c = 1056.9(2) pm, R = 0.030.