Volume 37, Issue 1

The compounds η 7 -C 7 H 7 Mo(CO) 2 R (R = CH 3 , C 6 H 5 ) were synthesized and characterized. The SO 2 -insertion into the Mo-C bond of the methyl and phenyl species was accomplished by condensing dry SO 2 into the ether solutions of the compounds. The SeO 2 and TeO 2 insertion was only successful with the methyl compound activating the dioxides in a metal vapour apparatus. There is strong evidence that Zn can also be inserted in the Mo-C bond of η 7 -C 7 H 7 MO(CO) 2 CH 3 .

The mixed-valence compounds of composition C 7 H 7 (CO) 2 Mo(μ-NR 2 ) 3 MoC 7 H 7 (R=H, p-NO 2 -C 6 H 4 , C 4 H 4 ) can be synthesized by reacting η 7 -C 7 H 7 Mo(CO) 2 Br with the corresponding sodium amides. The amido compound with R=H can also be obtained from η 7 -C 7 H 7 MO(CO) 2 CH 3 in liquid ammonia. Reaction of the products with CH 3 OH yields the known complex η 3) -C 7 H 7 (CO) 2 Mo(μ-OCH 3 ) 3 Mo-η 3 -C 7 H 7 .

The title compounds have been synthesized and characterized by elemental analysis, IR and 1 H NMR methods and mass spectra. The crystal and molecular structures of the binuclear complexes [η-C 5 H 5 (NO)Cr(μ-SeC 6 H 5 ) 2 Cr(NO)-η 5 -C 5 H 5 ] and [η 5 -C 5 H 5 (NO)Crμ-Se-n-C 4 H 9 )(μ-OH)Cr(NO)-μ 5 -C 5 H 5 ] have been determined by X-ray structure analysis. The latter is shown to have a four-membered ring consisting of two chromium atoms, one selenium, and one oxygen atom.

C 6 H 5 OP(X)Cl 2 (X=O, S) reacts with 1,2-dimethylhydrazine, 1,1-dimethylhydrazine or methylhydrazine, resp., to give the new dihydrazido derivatives la, 2a, 2b, or 3a and 3a-1, resp. Their 1 H NMR and 31 P NMR data are given.

27 Al NMR studies of AlCl 3 solutions in diethyl ether reveal the presence of AlCl 4 at high concentrations. This ion can also be recognized besides AlCl 3 ·OR 2 at low temperature in dilute solutions, while at 25 °C a single signal is observed, which represents the average of all species in solution. More extensive dissociation of AlCl 3 results in tetrahydrofuran. The main species in equilibrium with one another are AlCl 3 ·2THF, AlCl - 4 and AlCl 2 (THF) + 2 . Nearly quantitative dissociation to yield AlCl - 4 and [AlClL 5 ] 2+ occurs in dilute solutions of AlCl 3 in monoglyme (L reprents one oxygen donor atom); at higher concentration an adduct AlCl 3 ·L with Al in a tetrahedral environment is also present. This trend towards extensive dissociation is also observed in the solutions of AlCl 3 in diglyme and triglyme. Relative peak areas are in agreement with the formation of a 1:1 electrolyte [AlCl 2 L 4 ] + AlCl - 4 in diglyme, whereas additional dissociation into [AlClL 5 ] 2+ and AlCl - 4 occurs in triglyme.

The 31 P NMR Spectra of PCl 3 NPCl 2 O (1) and the homologous compounds 2-4 do not indicate any rotational isomers in the temperature range 183-413 K. The observed values for ν/2 depend on the viscosity of the solvent and on the temperature of the sample. They are reduced to T 1 relaxation effects, where the spin rotational mechanism may be dominant in the case of the small molecules and the PCl 3 group.

3,5-Dibromo-1,2,4-trithia-3,5-diborolane reacts with alkynes to give ⊿ 4 -2-bromo-1,3,2- dithiaborolenes. As a by-product in the reaction to form ⊿ 4 -2-bromo-4-phenyl-1,3,2-dithiaborolene the ⊿ 2,5 -4-bromo-2,6-diphenyl-l,4-thiaboracyclohexadiene is formed. Vinyltrimethylsilane reacts with 3,5-dimethyl-1,2,4-trithia-3,5-diborolane to yield the 2-methyl-4- trimethylsilyl-1,3,2-dithiaborolane. The bromine atom in these compounds can be substituted by lithium alkyls, by secondary as well as lithiated primary amines or by lithiohexamethyldisilazane. Starting from ⊿ 4 -2-<-butylamino-4-phenyl-1,3,2-dithiaborolene and heterocycles containing boron bromine functions, diborylamines are obtained. Isocyanates and di-i-propylcarbodiimide, respectively, react with 3,5-dimethyl-1,2,4-trithia-3,5-diborolane by formation of 5-methyl-1,4-dithia-2-azacyclopentanethiones(3) or of -pentanones(3). 3,5-Dimethyl-1,2,4-trithia-3,5-diborolane reacts with o-acetylaminophenole to give 3-acetyl-2-methyi-4,5-benzo-l-oxa-3-aza-2-boracyclopentane. 1 H, 11 B, 13 C NMR, mass and IR spectra are reported.

A single crystal X-ray structure analysis of orthorhombic BaCrF 5 (a = 1393.8(1), b = 571,1(1), c = 494,7(1) pm), which crystallizes in the structure type of BaGaF 5 , space group P2 1 2 1 2 1 , yielded Cr-F distances in the range of 187.3 to 194.9 pm, average 190.2 pm. Using powder neutron diffraction data taken at 2.2 K a G-type antiferromagnetic structure with spin alignment along the c direction of the lattice was worked out. Single crystal susceptibility data were consistent with this model and in addition showed a small net moment, probably due to spin canting, to be present below the Neel temperature of TN = 3.4 K. The orientation of this moment along the b axis is in accordance with the space group symmetry as well, chemical and magnetic cell being the same. From powder susceptibility data an exchange energy of -3.74 K (g = 2.02) was obtained by fitting Fisher's model. The low bridging angle of Cr-F-Cr = 137.4° within the cis corner-sharing chain of octahedra is made responsible for the weak antiferromagnetism in BaCrF 5 , which is compared to that of other chromium(III) fluorides.

The phosphanes P(NH 2 )Hal 2 and P(NHMe) 2 Cl are stabilised as ligands in (CO) 5 MoP(NH 2 )Hal 2 [Hal = Cl (2), Br (3), I (4)] and (CO) 5 MoP(NHMe) 2 Cl (10) by reactions of (CO) 5 MoP(NH 2 ) 3 (1) with HHal or of (CO) 5 MoP(NHMe) 3 (8) with HCl, respectively. 4 decomposes at room temperature and reacts with t-BuNH 2 to give, (CO) 5 MOP(NH-t-BU) 2 NH 2 (6). 1 and HI form (CO) 5 MoPI 3 . 3 can also be prepared from 2 with HBr, 4 from 2 and 3 with HBr and HI, respectively. The reactions of 2-4 with NR 3 produce polymers, whereas the reaction of 3 with pyridine leads to (CO) 5 MoNC 5 H 5 . The mixtures (CO) 5 MoP(NHMe)Br 2 /(CO) 5 MoPBr 3 and (CO) 5 MoP(NH-i-Pr) 2 Cl/(CO) 5 MoP(NH-i-Pr)Cl 2 are isolated from reactions of 8 with HBr and of 9 with HI, and 9 reacts with HBr to give (CO) 5 MoPBr 3 . (CO) 5 MoP(NHMe)I 2 is formed in small amounts by the reaction of 8 with HI, the main product is an insoluble solid, which is probably the impure intermediate [(CO) 5 MoP(NHMe)(NH 2 Me) 2 ] 2+ 2I - . Reaction of 10 with NEt 3 leads to the formation of the dinuclear complex 12 in which the new diazadiphosphetidine [MeNHP-NMe] 2 functions as a bridging ligand between two (CO) 5 Mo units.

The organometallic anion in tetraethylammonium-tricarbonyl(3,5-diphenylthiacyclohexadienyl-1-oxide )molybdate and its tungsten analogue can be halogenated by treatment with iodine, C 5 H 5 N·Br 2 , and I,I-dichloroiodobenzene to yield neutral [η 5 -C 5 H 3 (C 6 H 5 ) 2 SO]M(CO) 3 X complexes (M=Mo, W; X=Cl, Br, I).

1,1,1-Tris(dichlorarsinomethyl)ethane, CH 3 C(CH 2 AsCl 2 ) 3 (5) can be obtained in the reaction of CH 3 C(CH 2 AsNC 6 H 4 CH 3 ) 3 (4) with gaseous HCl. The heteroadamantane CH 3 C(CH 2 AsO) 3 (6) reacts with AsCl 3 or PCl 3 yielding also 5. CH 3 C(CH 2 AsO) 3 , CH 3 C(CH 2 AsS) 3 and CH 3 C(CH 2 AsI 2 ) 3 are oxidized with H 2 O 2 to give CH 3 C[CH 2 As(O)(OH) 2 ] 3 (7) and CH 3 C[CH 2 As(O)(OH) 2 ] 3 ·H 2 O (7 a). CH 3 C(CH 2 AsI 2 ) 3 and C(CH 2 AsI 2 ) 4 can be reduced with LiAlH 4 to give CH 3 C(CH 2 AsH 2 ) 3 (9) and C(CH 2 AsH 2 ) 4 (12). Oxidation of 9 and 12 leads to the cyclotriarsane compounds CH 3 C(CH 2 As) 3 (10) and H 2 AsCH 2 C(CH 2 As) 3 (13).

N-Heterocyclic Compounds N,N-Dimethyl-N′,N′-bis(trimethylsilyl)hydrazine reacts with fluorophosgene to yield 5,5-dimethyl-3-dimethylamino-2,4-dioxo-5-azonia-imidazolidide (1). With phosgene, 1-methyl-2-chloroformyl-4-dimethylamino-1,2,4-triazolidine-3,5-dione (5) can be prepared. The thermal decomposition of N,N-dimethyl-N'-carbomethoxi-N′-trimethylsüyl-hydra-zine gives 1,3,5-tris(dimethylamino)-1,3,5-hexahydrotriazine-2,4,6-trione (2) and 1,2-dimethyl-4-dimethylamino-1,2,4-triazolidine-3,5-dione (3). 2 can also be prepared by thermal decomposition of N.N-dimethyl-N′-carbomethoxi-N′-fluoroformylhydrazine (4). The crystal and molecular structures of 1 and 2 were determined by X-ray analysis. The 1 H NMR and vibrational data of 1-5 were communicated. The mass spectra of 1-3 were measured and discussed.

Chlorotrimethylsilane and sodium/potassium bismuthide, easily prepared from finely powdered bismuth and sodium potassium alloy in 1,2-dimethoxyethane (DME), react to give tris(trimethylsilyl)bismuthine (1) in 48% yield. When compound 1 is treated with chlorotrimethylstannane all trimethylsilyl substituents are successively replaced by stannyl groups, and tris(trimethylstannyl)bismuthine (4) is obtained. As in analogous reactions of other tris(trimethylsilyl) derivatives of Vb-elements with methyl lithium in diethylether/tetrahydrofuran (THF), one trimethylsilyl group of tris (trimethylsilyl)-bismuthine (1) can also be removed, and lithium bis(trimethylsilyl)bismuthide · 2 THF (5) is formed. With 1,2-dibromoethane bismuthide 6 reacts with metal halogen exchange to give green lustrous needles of tetrakis(trimethylsilyl)dibismuthine (6). In contrast to other dibismuthines described in the literature, this compound is thermally rather stable and can be isolated in preparative amounts. Similar to several distibines a colour change from green to red, resp. orange-red occurs on melting or dissolving dibismuthine 6 in organic solvents.

The mechanism of the electrochemical reactions of 1-nitro-2-naphthol, o-nitrophenol and p-nitrophenol at carbon fibre electrodes is investigated in aqueous solutions with pH= 1-10. The above nitrophenols are reduced to the corresponding amines, which are reoxidized to quinone imines. As the quinone imines are partially hydrolysed to quinones, the kinetic of this hydrolysis reaction is also examined. In the case of 1-nitro-2-naphthol the hydrolysis rate constant of 1,2-naphthoquinone imine is estimated as a function of pH by cyclic voltammetry.

The ESR spectra and the temperature dependence of the magnetic susceptibility of Cu(NCO)2(pyridine)2 were measured. The ESR spectrum at room temperature shows a single reversed line; at -130 °C it is isotropic. The susceptibility down to 4.2 K obeys the Curie-Weiss law with a small θ value. These results are interpreted on the basis of the known crystal and molecular structure.

Cyclic β-dicarbonyl compounds (1,4,7,10) were reacted with either aniline or urea in the presence of trimethoxymethane to give the enamines 2, 5, 8 and 11, resp. The latter were reduced with hydrogen over palladium-charcoal or with the dimethylamine-boron-hydride complex to give the C-methylated β-dicarbonyl compounds 3,6,9 and 12, resp. in moderatly to good overall yields.

In the new compound Pb 9 Al 8 O 21 parts of Pb 2+ are replaced by Sr 2+ . Isolated crystals of Pb 8 Pb 0,6 Sr 0,4 Al 8 O 21 were investigated by single crystal work (space group Pa 3-T 6 h ; α = 13,26 Å; Z = 4). It can be shown, that the Pb 2+ ion in the position 4b (posessing an untypical 2+6 coordination) is partly substituted by Sr 2+ .

By reaction of cupric chloride with sodium azide and hexamethylenetetramine in aqueous solution crystals of the title compound could be obtained. An X-ray analysis showed the compound to contain a dimeric cuprate(II) anion with terminal as well as bridging azido groups.

In the electrochemical reduction of 1-nitro-2-naphthol at carbon fibre electrodes an adsorption peak cathodic of the diffusion-controlled peak is obtained, as it happens in processes involving a strong adsorption of the reactant. This adsorption peak appears when the electrodes remain at positive potentials (+1V) in acidic solutions of the nitronaphthol and its interpretation is corroborated by its scan rate and concentration dependence.

The 4-methylthio-2-azetidinones 1a-d react with lithiumiodide/pyridine by stereoselective 1,4-ringopening to the E/Z 3-methylthioprope-noicacid anilides 2b-e. The attempted selective O-alkyl cleavage 1a→1e failed.

Solution-phase photoreactions of 4-amino-substituted 1,2,4-triazin-5(4H)-ones (1a-j) in different solvents using UV light with wavelengths greater than 290 nm have been investigated. The results show, that the desamination reaction is influenced by both oxygen and water. The photoexperiments showed clearly that OOH-radicals take part in the first step of reaction.