Volume 31, Issue 11

The title compound 2 crystallizes monoclinic, and the space group was determined to be C 2/c. The unit cell contains 16 molecules grouped in two sets of crystallographic independent molecules. The structure was solved by direct methods. Full matrix refinement led to R = 0.09. The molecules have C 2 symmetry. The compound is composed of two five membered diazaborolidine rings joined by a boron-boron bond. The two nearly planar rings are twisted to one another by 61.6° and 56.8° respectively

Aluminium nitrogen compounds having an adamantane cage structure 1 are produced from aminoalanes HXAlN(CH 3 ) 2 (X = H, Cl, Br, I) and primary amines. The hydridic Η-atoms of [(R 2 NAlH) 2 NR] 2 (R = CH 3 ) can be replaced by halogen using mercury halides. In contrast, methylation was not achieved by Hg(CH 3 ) 2 or Al(CH 3 ) 3 · O(C 2 H 5 ) 2 respectively. LiAlH 4 and (CH 3 ) 2 NH degrade the adamantane skeleton with aminoalane formation. The spectroscopic data of the new compounds will be discussed

The crystal structure of triclinic [enH 2 ][VOF 5 ], prepared in aqueous solution, has been determined from X-ray diffractometer data (R = 0.076 for 527 reflections). The structure contains monomeric [VOF 5 ] 2- -ions. The bond distances are 1.54(1) Å (terminal oxygen), 1.80(1) (average for the cis-fluorine atoms) and 2.10(1) Å for the fluorine atom in transposition to the terminal oxygen atom. This fluorine atom is involved in strong hydrogen bonds originating from the [NH 3 CH 2 CH 2 NH 3] 2+ cation with cisoid conformation. Earlier results about the existence of K 2 VOF 5 could not be confirmed

The high-pressure phases CsClO 4 IV and CsBF 4 IV have been quenched to atmospheric pressure at 100°K. The powder patterns can be indexed on the basis of tetragonal cells with a 0 = 12.965, 12.728 Å, c 0 = 5.230, 5.126 Å, respectively, containing eight formula weights. The cell volumes are in excellent agreement with the values expected from direct measurements of the III (barite)/IV transition volume changes. Arguments are advanced to show that these high-pressure phases, slightly more densely packed than the scheelite structure, probably contain the large cations in eightfold sites, the smaller ones in tetrahedral sites, and have cation-cation coordination numbers of approximately eight

The new intermetallic compounds CaMn 2 Sb 2 , SrMn 2 Sb 2 and CaMn 2 Bi 2 have been prepared and structurally characterized. They are isotypic and crystallize trigonal in the anti-Ce 2 O 2 S-structure with the lattice constants: CaMn 2 Sb 2 : a = 4.54(1), c = 7.48(1), c/a = 1.65. SrMn 2 Sb 2 : a = 4.56(1), c = 7.70(1), c/a = 1.69. CaMn 2 Bi 2 : a = 4.63(1), c = 7.64(1), c/a = 1.65.

The reduction of SnCl 4 , PCl 5 and SbCl 5 by diazadiphosphetidines with formation of diazaphosphoniumphosphetidines and the anions SnCl 3 - , Cl - and SbCl 4 - is described. With SnCl 4 a 1:1 adduct has been isolated as the primary product

Hydrido-cyclotri(phosphazen)es can be coupled by one or two step oxidation to give symmetric and unsymmetric bis[cyclotri(phosphazen)yl]oxides. Their structure follows from the analysis of their NMR spectra

Since the O/F sites in KCrO 3 F are statistically occupied by both ligands only average metal ligand distances can be obtained by the usual single crystal structure determination. Fourier transformation of the reduced intensity distribution of the crystalline powder, however, yields the radial distribution function in which all interatomic vectors are put into a one-dimensional common scale with the same origin. From an analysis of this function the distances d(CrO) = 1.615(20) and d(CrF) = 1.78(3) Å were obtained. By the same technique also KCrO 3 Cl and Na 3 CrO 4 were investigated resulting in d(CrO) = 1.617(20) and d(CrCl) = 2.183(35) for the former and d(CrO) = 1.70(2) Å for the latter compound

The He I photoelectron spectra of the series R n P(CN) 3-n (R = Me, CF 3 ; n = 0, 1, 2, 3) and of Me 2 ECN (E = N, P, As) are interpreted. The PE assignments are based on the comparison with the PE data of analogous halogeno and hydrogen derivatives as well as related cyano compounds and on simple MO considerations (composite molecule-approach). Hyperconjugative and inductive effects of the substituents CN, Me, F, Cl, and especially CF 3 are assessed. The various effects of changing substituents or central atoms within the series are used to confirm the interpretation. The differing electronic structures of halogeno and cyano (pseudohalogeno) compounds are discussed on the basis of their PE spectra

Reaction of fluorosulphonyl isocyanate with excess (CF 3 ) 2 CN 2 (1) gives the oxathiazoline (3); the isomeric oxathiazole (5) is obtained from perfluoro isopropyl sulphonyl isocyanate and 1. 3 is hydrolized much more readily than 4, from these reactions 2,2,5,5-tetrakis-(trifluoromethyl)oxazolidone or (CF 3 ) 2 CF-SO 2 NH 2 are isolated

The nuclear quadrupole resonance of 14 N was observed in K 2 Pt(SCN) 6 and K 2 Hg(SCN) 4 at various temperatures. Both compounds yield large asymmetry parameters indicating the existence of asymmetric π-electron distribution about a CN bond axis. The ionic character of metal-ligand bonds in the platinum and mercury complexes is estimated to be 28% and 58%, respectively. The temperature dependence of each component of quadrupole coupling can practically be interpreted in terms of a simple Bayer theory. Both complexes show the quadrupole coupling constant versus temperature curve faintly convex to the abscissa. This anomaly is attributable to vibronic interaction in a thiocyanate group

Both mononuclear Cr(CO) 5 (C 2 H 2 N 4 ) and binuclear [Cr(CO) 5 ] 2 (C 2 H 2 N 4 ) are formed when s-tetrazine (C 2 H 2 N 4 ) is added to a photolysed solution of Cr(CO) 6 in diethyl ether. A centrosymmetric structure is proposed for the binuclear, s-tetrazine-bridged complex [Cr(CO) 5 ] 2 (C 2 H 2 N 4 ). The corresponding molybdenum and tungsten compounds are also described

In the reaction of [C 5 H 5 Mn(NO)(CO)PN*]PF 6 (1) with LiC 6 H 5 5-exo-C 6 H 5 C 5 H 5 Mn(NO)-(CO)PN* (2) and C 5 H 5 Mn(NO)(COC 6 H 5 )PN* (3) are formed. If the reaction is carried out with optically active starting material 1 the optically active ring addition and benzoyl compounds 2 and 8 resp., are obtained. Whereas the ring addition product 2 is configurationally stable, the benzoyl complex 3 in solution epimerizes according to 1 st order kinetics. The change of configuration at the Mn atom occurs by PN* dissociation with formation of a chiral intermediate. This is demonstrated by the fact that exchange of PN* in (-) 578 -C 5 H 5 Mn(NO)(COC 6 H 5 )PN* (1a) with P(OC 2 H 5 ) 3 gives (+) 578 -C 5 H 5 Mn(NO)-(COC 6 H 5 )P(OC 2 H 5 ) 3 (4a), a reaction proceeding with retention of configuration at the metal atom

AgN(SO 2 F) 2 reacts with a variety of transition metal carbonyl and nitrosyl halides with exchange of N(SO 2 F) 2 versus halogen leading to stable bis(fluorosulfonyl)amido complexes (3-8). Triphenylphosphine replaces the weakly σ-donating (FSO 2 ) 2 N ligand with formation of cationic triphenyl phosphine transition metal complexes, e. g. (CO) 5 MnN(SO 2 F) 2 + PPh 3 → [(CO) 5 MnPPh 3 ]N(SO 2 F) 2

Relative rate constants of OH radical and e aq - reactions have been determined by comparing, under steady x-irradiation, the effect of various solutes upon the radiationinduced chemiluminescence (RCL) of aqueous dye (DH) solutions, [DH + ·OH] + e aq - → DH* + OH - . The results abundantly confirm other published data. RCL changes upon addition of phosphates indicate prototropic reactions with the oxidized dye, D·+ H 2 PO 4 - ⇌ DH· + + HPO 4 2- , promoting or inhibiting the formation of semioxidized dye (DH· + ) as the most efficient RCL precursor. The RCL enhancement commonly observed upon addition of halides and pseudo halides is discussed at some length on the base of previous and present results in order to focus attention to the possible correlation between such RCL enhancement and the effect of halogen-sensitization in radiobiology. RCL results suggest that the halide transients formed from OH radicals, X - + ·OH → X· + OH - , are very powerful oxidizing agents reacting with aromatics by electron-abstraction rather than by addition or H-abstraction. The common application of I - and SCN - as competitors for the estimation of OH radical reactivities is being commented in the context

Hydrolysis of 4-Benzoyl-5-phenyl-2,3-dihydrofuran-2,3-dione (1) in water (ethanol) gives dibenzoylmethane and oxalic acid (ethyl ester). 1 reacts with aniline or p-toluidine yielding the 2-pyrrolones (2), which on the other hand are synthesized by addition of the corresponding anilines to the pyrrol-2,3-diones (8). 3 a adds methanol to give the 2-pyrrolone (4), which with aniline can be converted into 2 a. 2 a, b show fragmentation to oxalic acid anilides by heating (2 b) or treating with diazomethane (2 a). The reaction of 1 with p-nitroaniline leads via the furanone-derivative 6 to oxalic acid-di-p-nitroanilide. 1 and N-methylaniline combine to acrylic acid-N-methylanilide (7), which by heating gives the dibenzoyl acetic acid-N-methylanilide

The one-bond carbon-nitrogen coupling constant of diazomethane is reported. Analogies with carbon-carbon coupling constants in allenes are emphasized. CNDO/S-calculations are used as a support of the suggestions the C-N coupling in diazomethane to be dominated by the Fermi contact mechanism and the sign of the carbon-nitrogen-15 coupling constant to be negative

The combined action of orthoformate and aniline upon cyclohexanedione-1,3 yields anilinomethylene-cyclohexanedione-1,3, which react with cyanoacetate or malodinitrile in DMF in the presence of KOH to give ethyl-1-phenyl-2,5-dioxo-1,2,5,6,7,8-hexahydroquinoline-3-carboxylates (or -carbonitrils)

The reactions of dialkyl N-alkyl phosphoramidates (1) with benzene in the presence of aluminium chloride give aralkyls arising from cleavages of the P-O-C and N-C bonds. Analogous reactions of diphenyl N-alkyl phosphoramidates (2) and triamides (4), (RNH) 3 P(X), (X = O, S; R = alkyl) also give aralkyls; however, in these cases only N-C bond cleavage occurs. The reaction is not general, i. e., it is limited to phosphoramides derived from primary amines, and no reaction occurs with almost all phosphoramides derived from secondary amines. In addition not all phosphoramides which undergo N-C cleavage yield alkylation products

Mössbauer parameters (IS and NQS) for a series of hydrated sodium pentacyano-L ferrates(II) (L = monoprotonated diamines or nitrogenated heterocycles) are presented. Results are discussed in terms of electronic properties of the ligands. A tentative distinction between σ-and π-bonding effects is shown and comparisons are made with previous results reported for related substances

By investigations in the system Li(Na)-Be-As we found two new phases of the formula LiBeAs and NaBeAs which crystallize in a tetragonal resp. hexagonal structure

In the systems Na(K)-Zn(Cd)-As(Sb) we found the following phases: NaZnAs, NaZnSb, KCdAs, KCdSb (tetragonal symmetry); KZnAs, KZnSb (hexagonal symmetry); NaCdAs, NaCdSb (orthorhombic symmetry)

By neutron diffraction we found a decision on the distribution of the Al-Si(Ge)-atoms and the location of the lithium-atoms in the structures of the compounds LiAlSi and LiAlGe

The title compound was prepared for the first time by thermal dissociation of BiSCl as well as by sintering of 2 BiSCl + Bi 2 S 3 at 340°C. Bi 4 S 5 Cl 2 crystallizes rhombohedrally, its hexagonal lattice parameters are α = 19.804(5) and c = 12.359(3) Å; X-ray powder diffraction data are listed

The new oxide NaAg 3 O 2 , which was prepared using oxygen pressures of 350 at, is isostructural to LiAg 3 O 2 : Ibam, a = 6.159, b = 10.439, c = 5.972 Å

The reaction of tert-butylamino-fluoro-phenyl -tetramethylpiperidino-silane and butyllithium takes places under LiF- and C 4 H 10 -elimination. The proton, required for the formation of butane, is not transferred from the amino but from one of the methyl substituents of the piperidino ring under formation of a bicyclic structure

The title compounds, bicyclic B-O-B bridged dimeric amidoboranes, obtained together with substituted halogenoimines by reaction of N-substituted trifluoroacetamides with BCl 3 or BBr 3 , are characterised by 11 B and 19 FNMR, IR and mass spectra. Possible alternative and/or mesomeric structures are discussed

NdI 2 , which crystallizes in the SrBr 2 -type arrangement, has been transformed into a high pressure modification having the same MoSi 2 -type structure as the metallic diiodides of La, Ce and Pr

The new intermetallic compound SiAs 3 crystallizes monoclinic, space group C2/m (a = 9.61(1) Å, b = 7.63(1) Å, c = 5.88(1) Å, β = 112.9(1)°). The anionic part of the structure contains puckered layers of two- and threebonded As-atoms