Volume 42, Issue 8

Gd 2 B 5 is synthesized from Gd and B in the presence of GdCl 3 as a flux. The compound crystallizes in the monoclinic space group P2 1 /c with a = 713.6(1), b = 715.9(1), c = 718.3(1) pm and β =102.68(1)°. The structure consists of a 3-dimensional framework of Bft-octahedra and two types of B 2 -units enclosed in 32434-nets of Gd atoms. The different B -B-distances are discussed in terms of connectivity and Pauling bond orders.

The methylbis(thiophenolato)bismuth(III) derivative CH 3 Bi(SCAH 3 Cl 2 -2.6) 2 was prepared by reaction of CH 3 BiBr 2 with equivalent amounts of the appropriate lithium thiolate. The new Bi organyl was characterized by elemental analysis, 1 H NMR. IR . and mass spectroscopy. The biological activity against bacteria, yeasts, and moulds was investigated.

The donor acceptor complexes WC13(N 3S2)-L (L = TH F, pyridine), and [WCl 3 (N 3 S 2 )] 2 · dipy are prepared from WCl 3 (N 3 S 2 ) and the corresponding donor molecules. WBr 3 (N 3 S 2 ) ­ THF is formed by the reaction of WCl 3 (N 3 S 2 ) THF with BrSiMe 3 . The complexes have been characterized by their IR spectra. The crystal structure of WCl 3 (N 3 S 2 ) THF was determ ined by X-ray diffraction. It crystallizes monoclinically in the space group P2 1 /c with four formula units per unit cell (1903 observed, independent reflexions, R = 0.031); the cell dimensions are a = 1072.0. b = 1007.2, c = 1128.9 pm; β = 94.84°. The tungsten atom is a member of a nearly planar WN 3 S 2 ring with WN bond distances of 180 and 184 pm, which correspond to double bonds. The sixfold coordination of the W atom is completed by three chlorine atoms and the O atom of the tetrahydrofuran ligand, which is coordinated in trans-position to one of the N atoms; the THF molecules forms a dihedral angle of 40.1° with the WN 3 S 2 ring.

[MoCl 4 (NPPh 3 )(pyridine)] · CH 2 Cl 2 is formed by the reaction of the cyclothiazeno complex [MoCl 3 (N 3 S 2 ) · (pyridine)] with triphenylphosphane in CH 2 Cl 2 solution. It forms red, moisture sensitive needles. [MoCl 4 (NPPh 3 )(C 5 H 5 N)] · CH 2 Cl 2 crystallizes monoclinically in the space group P2 1 /n with four formula units per unit cell (1934 independent observed reflexions. R = 0.057). The cell dimensions are a = 1165, b = 1473, c = 1696 pm; β = 107.82°. The Mo atom is coordinated by four chlorine atoms, by the N atom of the (NPPh 3 - ) ligand, and in trans-position to it by the N atom of the pyridine molecule. The Mo= N = PPh 3 group has a nearly linear MoNP axis (176.6°) with bond lengths of MoN = 172 pm and PN = 165 pm.

Six possible structures of As 2 W 18 O 62 6- are discussed, and an exact nomenclature is proposed. The structures of the isomeric title compounds (I and II) were determined by X-ray diffraction. I crystallizes in space group P I with lattice parameters a = 12.965(4), b = 14.803(5), c = 18.515(6) Å; a = 96.280(23)°, β = 91.420(25)°, γ = 115.320(25)°. The anion has the configuration first observed in K 6 P 2 W 18 O 62 · 14H 2 O (Dawson-structure). II was not known until now. It crystallizes in the trigonal space group R3 with lattice parameters a - b - 37.857(32). c = 13.108( 13) Å; α = β = 90°, γ = 120°. The structure of this anion differs from the Dawson-structure by the 60° rotation of both polar groups of three WO 6 -octahedra (β-type), followed by the 60° rotation of one of the two new AsW 9 O 31 -units. Both rotations are about the 3-fold axis. The anion is centrosymm etric. Vibrational spectra and preparation of the isomers are described.

The compound Co(acac) 2 (NO) (1) crystallizes in the triclinic space group P1̄ with lattice constants« - 806.4(2), b = 1095.3(7), c - 776.4(3) pm, α = 105.62(4), β = 113.18(2), γ = 75.14(3)°, Z - 2. The Co atom exhibits a square pyramidal coordination with the chelating acac ligands in the basis and the NO group at the apex, the angle Co - N - O being 120.4°. 1 is very sensitive to oxygen and, with air in aqueous acetone, yields Co(acac) 2 (NO 2 )(H 2 O) (2). 2 crystallizes in the monoclinic space group P2 1 /n with lattice constants a = 704.9(9), b = 1314.2(7). c - 1451.3(7) pm. β = 97.93(2)°, Z = 4. The structure of 2 is built up by octahedral complexes with the aquo and the nitro ligand in trans positions. A CH 2 Cl 2 solution containing 1 and Co(acac) 2 reacts with O 2 , to form CO 5 (acac) 8 (μ-OH ) 2 (μ - N, O -NO;)2 (3) which precipitates on cooling to - 30°C and addition of hexane. 3 crystallizes in the monoclinic space group P2/n with a = 2227(1), b = 1128.9(7), c = 2293(2) pm, β = 104.79(3)°, Z - 4. The structure consists of pentanuclear complexes with C 2 symmetry. Two Cortriangles sharing one corner are each bridged by one μ 3 - OH -group. The NO 2 ligand functions as a N,O-bonded bridging group. The acac ligands complete the coordination of the Co-atoms to distorted octahedra.

Square planar iridium(I) complexes of sulfur monoxide and sulfur dioxide undergo oxidative addition with dihydrogen and hydrogen chloride. The resulting hydrido-iridium(III) complexes have been characterized by 1 H , 31 P NMR and IR spectroscopy. The limited stability of the sulfur monoxide derivatives is explained as resulting from decreased back-bonding between iridium and sulfur.

Single crystals of EA[Q(NO 2 ) 2 O 4 ] · 4H 2 O (EA = Ca. Sr) were grown in aqueous silicagel. Ca 2+ has CN 8. It is surrounded by 4 oxygen atoms of two bis-chelating [C 6 (NO 2 ) 2 O 4 ] 2- ions and 4 water molecules, which form a distorted, bi-capped trigonal prism. Sr 2+ is coordinated similarly, with an additional water molecule joining the coordination sphere to yield CN 8+1. Corrugated chains extending along [010] and consisting of EA 2+ and nitranilate ions are the main feature of the crystal structure. Adjacent chains are interlinked by hydrogen bonds.

Lithiumorganyls RLi (R = Me, Bu, Ph) add to (PhP) 5 in successive degradation and disproportionation equilibria depending on the ratio of the reactants. At -70 °C (R = Me) disproportionation is blocked and (PhP) 4 R - and (PhP) 3 R - can be detected. With excess RLi m onophosphides PhPR - are formed. CpNa with the help of a crown ether degrades (PhP) 5 or substitutes cyanide from PhPCN - to give an equilibrium mixture of (PhP) n Cp - anions, which stabilize by proton shifts: In case of n = 1 and 2 a shift from the Cp unit to the terminal phosphorus results in the formation of the phenylphosphino- and diphenyldiphosphino-cyclopentadienide anion, in case of n = 3 two proton shifts within the Cp unit result in a cyclopenteno-l,2,3-triphospholene allylic anion.

The reactions of F 3 CP = CF 2 (1) with Me 3 GeH, Me 3 SnH, and (C 5 R 5 )(CO) 3 MH (M = Cr. Mo, W; R = H , Me) proceed via addition to the PC double bond yielding tertiary phosphanes of the type Me 3 M′P(CF 3 )CF 2 H[M′ = Ge (2), Sn (3)] or (C 5 R 5 )(CO) 3 MP(CF 3 )CF 2 H [R = H; M - Cr (6), Mo (7). W (8); R = Me; M = Mo (9), W (10)]. 2 and 3 are labile compounds, which decompose by elimination of Me 3 M′F , a reaction which in the case of 3 has been used to prepare the new phosphaalkene F 3 CP = C(H)F (5) and its [2+4]-cycloaddition product 4 with 2.3-dimethyl-1.3- butadiene. The H substituent (instead of F) in 5 and its derivatives has a surprising influence not only on the stability of the compounds but also on their spectroscopic data, as shown by com parison with 1 and derivatives of the type Me 3 M ′P(CF 3 ) 2 and (C 5 H 5 )(CO) 3 MP(CF 3 ) 2 . respectively. New compounds are characterized by NMR, MS. GC/MS and IR measurements.

The reaction of mer-tricarbonyl-nitrosyl-bis(triisopropylphosphite)tungsten hexafluorophosphate (1a) with MeMgl or Bu 4 NI affords tricarbonyl-iodonitrosyl-(triisopropylphosphite)tungsten (2). Similarly, a carbonyl group of la can be replaced by a fluoride ion resulting in transdicarbonyl- fluoronitrosyl-bis(triisopropylphosphite)tungsten (3). Oxygen nucleophiles like OPh - , OCH 3 - or OH - either substitute or attack a carbonyl group in la and cause formation of dicarbonyl-nitrosyl-bis(triisopropylphosphite)tungsten phenoxide. methoxide or formate derivatives (4, 5 or 7). respectively. Nitrite ions react with la under CO substitution and bind as nitro ligands to the tungsten center. Addition of equivalent amounts of MeLi, PhLi and NaBH 4 to la leads to the formation of tricarbonyl-nitrosyl-(triisopropylphosphite)tungsten methyl and hydrido compounds (8a, 11a) as well as to dicarbonylnitrosyl-bis(triisopropylphosphite)tungsten methyl, phenyl and hydrido complexes (8b, 10 and 11b ) . In the presence of an excess of MeLi., la is transformed to a β-diketonate derivative 9.

A new neo-clerodane diterpenoid, montanin G was isolated as a minor compound from the aerial parts of teucrium montanum var. scorpilii. Its structure 19.6α-diacetoxy-3β-hvdroxy- 4α . 18:15,16-diepoxy-neo-clerodane-13(16).14-dien-20.12R-olide was established by chemical and spectroscopic means and by correlation with teupireinin.

The mercuration of 5,10,15,20-tetrakis(4-methylphenyl)porphyrin complexes M(TTP)** (2a-c; M = Ni, Pd, Pt) is described. Treatment of Ni(TTP) (2a) with mercuric acetate in refluxing benzene and subsequently with aqueous sodium chloride yields a mixture of species M(TTP-Hg n I n ) (1 < n < 3) from which the monomercurial, Ni(TTP-HgCl) (3a) is isolated in 35% yield after silica chromatography. A more rapid reaction occurs with mercuric trifluoroacetate in chlorobenzene. With this system, Pd(TTP-HgCl) (3b) and Pt(TTP-HgCl) (3c) along with their bis-, tris-, and tetrakis-mercurated analogs are obtained. The reaction times indicate that replacement of Ni II by Pd II and Pt II progressively diminishes the rate of electrophilic attack at the porphyrin periphery, consistent with a decrease of the total density of negative charge on the porphyrin ligand in these complexes.

Reaction of the Grignard-Reagent ClMgCH 2 OCH , (2) with (RCp) 2 TiCl 2 (5a) (R = H). 5b (R = CH,) yields the titanocene(methoxymethyl)chlorides (RCp) 2 Ti(Cl)CH 2 OCH 3 , 7a and 7b. Thermal decomposition of 7b (2 min, 110 °C in toluene) yields the paramagnetic titanium (III) complex [(CH 3 Cp)Ti(OCH 3 )Cl] 4 (8) in addition to the organic products ethylene and dimethvlether. The tetranuclear complex 8 crystallizes in space-group P2 1 /n with a = 9.125(2), b = 8.899(1), c = 20.226(2) Å and β - 92.804(9)°. In 8 the Ti 4 -core is alternatingly doubly-bridged by μ-chloro- and μ-methoxy ligands.

The structure of 1-O-(13-methyl-1-Z-tetradecenyl)-2-O-(13-m ethyltetradecanoyl)-glycero- 3-phospho-ethanolamine isolated from Myxococcus stipitatus has been elucidated. 1 H and 13 C NMR as well as mass spectral data have been accumulated which allow a ready identification and structure elucidation of compounds of this type.

The high frequency 1 H and 13 C NMR spectra (at 500 and 75.47 MHz, respectively) of N-allyl- N-normetazocine (NAM) hydrochloride in 2 H 2 O solution were run and fully analyzed with the aid of both homonuclear 1 H - 1 H and heteronuclear 13C - 1 H chemical shift correlation experiments. Selective broadening of the signals of the protons in 3-, 4-, 8-, 9-, 12-positions was observed at temperatures <350 K. This was found to be consistent with an inversion process occurring between the N-equatorial and N-axial configurational isomers of NAM whose rate of exchange is of the same order of magnitude of the chemical shifts differences at 500 MHz. The increase of temperature at 350 K is thus adequate to make “fast” the process in the NM R time scale and then to resolve the spectral portions. The experimental proton-proton coupling constants were found to be consistent with a slightly distorted chair conformation of the piperidinic ring in NAM hydrochloride. The 13 C NMR spectrum showed the distinct spectra of the two conformers, which are present in the ratio of ca. 80 (N-equatorial) : 20 (N -axial). The field frequency employed for the experiment was therefore sufficient to make “slow” the exchange process between the two isomeric forms, whose resonance peaks could be isolated in the non-acidified solution.

The electrochemical reductive silylation of N-alkoxyphthalimides leads to 2-alkoxy-1,3-bis- (trimethylsilyloxy)-isoindoles, which can be trapped by cycloaddition reactions with dienophiles like methyl acrylate and dimethyl acetylenic dicarboxylate. The unstable primary cycloadducts form naphthoquinones and dihydronaphthoquinones as monoxime derivatives. All oximes form syn and anti isomers.

2-Alkoxy-indoles 2a, b can be regarded as cyclic ketene-N.O -acetals. Their regiospecific [4+2]- Diels-Alder reaction with inverse electron demand with the triazine 3 yield in a one step addition the γ-carboline (4).

Enhydrazinones. prepared from dimedone and N,N-disubstituted hydrazines, react with formaldehyde and secondary amines to C-aminoalkyl-derivatives, pyrazolinium betaines and methylenebis( enhydrazinones). With better yields the C-Mannich products result from the reaction with methyleniminium salts. The enhydrazinones give with two moles of formaldehyde and primary amines the corresponding tetrahydropyrimidines.

2-(E)-Dim ethyl(chloro)stannyl-3-diethylboryl-2- pentene (lc) reacts with trimethyltin hydride (3) to give the corresponding alkenyl(dim ethyl)tin hydride (2). Compound 2 has been characterized by 1 H, 11 B, 13 C, 119 Sn NMR . Neither the NMR nor the IR data are in support of an intramolecular Sn-H-B bridge.

Starting from disodium 5-cyanoisothiazoledithiolate som e new substituted derivatives of the tetrathiafulvalene and some metal 1,2-dithiolenes with at least an isothiazolo-ring have been prepared. From these com pounds a number of conductive cation radical salts have been obtained.

A phase equilibrium study of the system aluminiumbromide and pyridiniumbromide has been carried out. The phase diagram of the system indicates the existence of three congruently melting com pounds of the molar ratio AlBr 3 /PyHBr 1:1, 1:3, 2 :3 and one incongruently melting compound of the molar ratio 1:2 and is therefore similar to the AlCl 3 -PyHCl system [1].