Volume 33, Issue 6

Bis(trimethylsilyl)aminoisocyanate (1) is formed by reaction of the hydrazides LiN 2 (SiMe 3 ) 3 or Li 2 N 2 (SiMe 3 ) 2 with phosgene. Bis(trimethylsilyl)aminoisothiocyanate (2) is obtained by thermolysis of the hydrazide (Me 3 Si) 3 N 2 CSSLi, which is readily prepared from LiN 2 (SiMe 3 ) 3 and carbon disulfide. (It is generally found that LiN 2 (SiMe 3 ) 3 and Li 2 N 2 (SiMe 3 ) 2 add to heterocumulenes X = C = Y (X = TosN, O, S; Y = O, S), and that reaction of the addition products with Me 3 SiCl yields (Me 3 Si) 3 N 2 CXYSiMe 3 . While 1 is obtained solely as a thermostable dimer, 2 is a thermolabile monomer). Thermolysis of 2 at ambient temperature yields (Me 3 Si) 4 NiC 2 S and (Me 3 Si) 4 NiC 2 S 3 . Thermolysis of 2 in ether solution at elevated temperatures mainly yields bis(trimethylsilyl)carbodiimide and sulfur

2,2'-Bipyridine-bis(o-phenylenedioxy)phosphonium hexafluorophosphate crystallises in the monoclinic space group C2/c (Z = 8) with a = 18.654(4), b = 10.131(2), c = 24.344(4) Å, β = 99.53(4)°. The cationic phosphorus atom displays an octahedral coordination slightly distorted towards the tetrahedral one of an uncomplexed phosphonium center. The OPO bond angles are between 91.6 and 95.7(2)°, the NPN angle of the bipyridine chelate ring in contrast is only 81.7(2)°. The ring systems of the bipyridine ligand are inclined slightly to one another at an angle of 4.7°. The bond lengths to the cationic phosphorus are P - 0 1.668-1.672(3), P-N 1.896(4) and 1.898(4) Å. The hexafluorophosphate anion is disordered

An X-ray crystal structure analysis of tetrakis(dimethylamino)(ethylenediamino)cyclotriphosphazene reveals a novel spirocyclic structure with the spiro ring having an envelope conformation. There is evidence for an intermolecular N-H ··· N bond in the crystal which persists in solution

K 3 CU 3 P 2 was obtained by melting potassium, copper and red phosphorus in an sealed copper vessel. The compound crystallizes trigonally with a = 572 ± 2 pm, c = 1993 ± 3 pm, R3m, Z = 3. The structure analysis revealed nets of puckered 12-membered rings in which the Cu-atoms are linearly coordinated while the P-atoms are located on the apices of trigonal pyramids

The new compound LisNaSiu has been prepared and its crystal structure determined. It crystallizes trigonal, a = 471.0 ± 0.6 pm, c = 3172 ± 5 pm, space group R3m-C 5 3V . Half of the Sn atoms build up a puckered net of connected six-membered rings, the other half is bound to the net atoms, forming a tetrahedral Sn-Sn coordination for these. The structural relations of this Sn sublattice to the diamond lattice are discussed

By mixing aqueous solutions of Hg(CH 3 COO) 2 and MOCN (M = K, Rb, Cs) the tri-clinic compounds M 2 Hg 3 (NCO) 8 are formed. In a first approximation the crystal structure analysis indicates isolated Hg(NCO) 2 molecules besides K+ and NCO - ions. As in the range of van der Waals radii additional NCO-neighbours are noticed the mercury atoms are surrounded by distorted octahedra. The octahedra around 2/3 of the Hg form infinite chains as in KHg(NCO) 3 which are linked together by additional Hg(NCO) 2 molecules. Therefore the compound can be formulated as a double salt 2 KHg(NCO) 3 • Hg(NCO) 2 . The vibrational spectrum is discussed. Rb 2 Hg 3 (NCO) 8 is isotypous while the caesium salt has a double cell volume.

The phenylalkyl arsine CH 3 C[CH 2 As(C 6 H 5 ) 2 ] 3 reacts with gaseous HI by selective cleavage of the arsenicphenyl bonds yielding CH 3 C(CH 2 AsI 2 ) 3 . This compound is characterized using IR, FIR, Raman, 1 H NMR and electron impact mass spectroscopy

Four ternary compounds with the formulas CaMn 2 P 2 , CaMn 2 As 2 , SrMn 2 P 2 , and SrMn 2 As 2 have been prepared and investigated by X-ray methods. They are isotypic and crystallize trigonally in a CaAl 2 Si 2 -type structure (space group P3̅m 1-D 3 3 d) with the lattice constants: CaMn 2 P 2 a = 4,096 ± 0,001 Å, c = 6,848 ± 0,002 Å, CaMn 2 As 2 a = 4,239 ± 0,001 Å, c = 7,027 ± 0,003 Å, SrMn 2 P 2 a = 4,168 ± 0,001 Å, c = 7,132 ± 0,001 Å, SrMn 2 As 2 a = 4,306 ± 0,001 Å, c = 7,315 ± 0,001 Å. The lattice constants of BaMn 2 P 2 and BaMn 2 As 2 are given

The crystal structure of the title compound was determined from single crystal X-ray data. The compound crystallises in the orthorhombic space group Pnma. In contrast to the solution where fluctuating P-Te bonds have been established by NMR analyses the crystals contain isolated molecules with fixed P-Te bonds (bond length: 235.4 pm). The four-membered phosphorus nitrogen ring exhibits significant deviations from planarity. The P-N bond lengths were found to be 168.3 and 175.0 pm, respectively

The complexing of thallous ions (T1+), with the crown ether dibenzo 18 crown-6 poly-ether (DB) has been studied by NMR, fluorescence, and pulse radiolysis techniques. NMR data show a strong interaction of the T1+ ions with the aromatic moieties. This is also illustrated by a static quenching of the aromatic fluorescence by Tl+ . The rates of reactions of T1+ with hydrated electrons e aq - and pyrene excited singlet states are decreases on complexing the ion by the crown ether.

Depending on the method of preparation ,,NiO”-single crystals of different colours can be synthesized. It is shown by ligand field spectroscopy that the ligand field and interelectronic repulsion parameters are the same for the green, yellow and brown crystals. There is definite spectroscopic evidence, that the colour of stochiometric NiO is green

The reaction of singlet oxygen with 1,3-diphenylisobenzofuran was investigated in aqueous micellar solutions of sodium dodecyl sulfate and dodecyl trimethylammonium chloride using pyrene as photosensitizer. Singlet oxygen, produced by the photosensitization of pyrene bound to micelles, oxidized efficiently 1,3-diphenylisobenzofuran bound to micelles. The quantum yield for singlet oxygen production and the rate constant for furan oxidation were determined by the kinetic analysis for the oxidation reaction of furan. Quenching of singlet oxygen by sodium azide competed with the furan oxidation, and its rate constant was also determined. Results obtained were compared with those in methanolic solutions. The quantum yield for singlet oxygen production and the rate constant for furan oxidation were much higher in micellar solutions than those in methanolic solutions. Empty micelles wxas found to act as a considerably strong scavenger for singlet oxygen. The penetration probability of singlet oxygen from aqueous phase into the interior of micelles which bound furan was also estimated

Semiempirical SCF-calculations show that the fluorescence bands of 7-hydroxycoumarin at 1.87 · 104-1,92 · 104 cm -1 are most probably due to a phototautomeric form. A topological rule is evaluated to explain the dependence of the fluorescence intensity upon the position of the hydroxyl group in the various isomeric hydroxycoumarines

There are numerous simple chemical reactions in which reaction products arise, which compared with the materials at the outset, possess a considerably greater surface area. A significant example is the reaction of aluminium alcoholates with water. Reactions of this kind can, to a certain extent, be used as auxiliary reactions, in order to distribute other materials homogenously. In the chosen example, a material dissolved beforehand in the alcoholate, e.g. a solution of a metal salt, would be transferred in the course of the distributing reaction into the newly-developing structure of the reaction product. In this publication the application of some catalysts thus prepared to some classical organic chemical reactions is described by way of example

From N-(hydroxymethyl)- and N-(chloromethyl)carboxylic acid amides (3) and (4) respectively by treatment with 2 or 1 mol phosphorus pentachloride respectively N- (chloromethyl)carboximidoyl chlorides (10) are formed. As side products in addition to acyl chloride (6) and carbonitrile (14) can be isolated tris(chloromethyl)amine (7), N- (chloromethyl)carboximidic acid chloromethylester (15), N-bis(chloromethyl)phosphoramidic dichloride (11) and l,3-bis(chloromethyl)-2,2,2,4,4,4-hexachloro-2,2,4,4-tetrahydro- l,3,2,4-diazadiphosphetidin (12)

3,4-Dihydroisoquinoline reacts with ethyl cyanoacetate in acetic acid/ acetic anhydride to yield the olefine 2. Cyanoacetic acid, ω-cyanoacetophenone and ω-nitroacetophenone act in the same way. Other CH-acidic compounds give addition reactions with 3,4-dihydroisoquinoline yielding 1,2,3,4-tetrahydroisoquinoline derivatives (9-22)

By gas-chromatographic analysis of products prepared by UV irradiation of uracil in water, acetonitrile or ice matrix resp. of thymine in actonitrile could be demonstrated, that in all cases all four cyclobutane dimers are formed

The reaction of the aminoiminothiophosphoranes (1) with methanol yields the bisamino-thiophosphoric acid derivatives (3). la and IVb → VTb element halides form the new P-N element four membered rings 4 →7, which partially exist as a mixture of eis and trans isomers. Different ylide group transfer is observed on the reaction of la with trimethyl -phosphine or trimethyl phosphite. With trimethylphosphine (CH 3 ) 3 P(S) and a phos-pha(III)azene are formed, with trimethyl phosphite (CH 3 O) 3 P = NC(CH 3 ) 3 and the [2 + 2] cycloaddition product of la and (R 3 C)(R 3 Si)N-P = S (R = CH 3 ) can be isolated.

The present paper deals with the kinetics of oxidation of D-galactose by Nessler's reagent in alkaline medium. The reaction is zero order with respect to Hg(II) and first order with respect to reducing sugar. The direct proportionality of the reaction rate at low hydroxide ion concentrations shows retarding trend at higher concentrations. The reaction rate is inversely proportional to iodide ion concentration. A mechanism has been proposed taking HgI 3 - as the reacting species

Treatment of a-phenylthiocarbamoyl acetyl acetone (1) with aromatic diazonium salts effects acetyl cleavage with the formation of 2-methyl-I-phenylthiocarbamoylglyoxal arylhydrazones (2a-c), which afford the anilinopyrazoles (5a-c) and the phenylimino-2- pyrazolines (6a-c) on treatment with hydrazine or phenyl hydrazine respectively. Treatment of diethyl a-phenylthiocarbamoyl malonate with aryl diazonium salts gave diethyl (arylazo)(phenylthiocarbamoyl) malonate which afford the 7-phenyl-5-(arylazo)- 2,3,7-triazabicyclo[3,2,0]hept-I-ene-4,6-dione (9a, b) and its 3-phenyl derivatives (9c, d) with hydrazines and phenyl hydrazine respectively

Fuchsone (4-diphenylmethylene-2,5-cyclohexadien-l-one) (1) eliminates CO upon gasphase pyrolysis. The resulting biradical (2) either formes by double ring closure and dehydrogenation benzo[c]phenanthrene (6) or recombines to 6,6-diphenylfulvene (3) which gives after dehydrogenative ring closure and rearrangement 1-phenylacenaphthylene (11)

In the photolysis of 5-bromouracil containing DNA Br atoms are expected inter mediates. In order to evaluate the possible site of attack of the Br atom at the sugar moiety of DNA the reaction of 2-deoxy-D-ribose with the Br atom (complexed with two bromide ions) was investigated. Hydroxyl radicals generated by the radiolysis of N 2 O saturated aqueous solutions were converted into Br 3 ·2- radicals by 1 M bromide ions. Br 3 ·2- reacts with 2-deoxy-D-ribose (k = 3.7 · 104M -1 s -1 , pulse radiolysis). The major product is 2-deoxy-D-erythro-pentonic acid (G = 2.4, γ-radiolysis). It is formed by hydrogen abstraction from C-l and oxidation of this radical by other radicals. An alternative route via the radical at C-2 is neglible. It follows that Br 3 ·2 - reacts preferentially at C-1 of 2-deoxy-D-ribose

Single crystals of Bi 2 Ga 4 O 9 and Bi 2 Ga 2 Fe 2 O 9 were prepared by CO 2 -Laser technique and analysed by X-ray single crystal methods. Bi 2 Ga 4 O 9 is one of the rare examples containing Ga 3+ in octahedral as well as tetrahedral surrounding of oxygen. In Bi 2 Ga 2 Fe 2 O 9 the coordination of oxygen atoms around Ga 3+ is exclusively tetrahedral. Thus this compound represents positive evidence of the preferential occupation of tetrahedral holes by gallium

By investigations in the systems Ca-Cu-P(As) we found two ternary phases of the formulas CaCuP and CaCuAs, which crystallize in a hexagonal lattice. We suppose a modified Ni 2 lntype structure. Some details about a Calcium Copper Phosphide with a ThCr 2 Si 2 -type structure are given

N -Trimethylsily 1 -triphenylphosphinimine re - acts with halogenoboranes R 2 BX (R = organyl, F, Cl, Br; X = F, Cl, Br) to yield triphenylphosphiniminodihalogenoboranes and triphenylphosphiniminodiorganylboranes, respectively. In solution, the dihalogeno compounds are associated, probably dimeric, while the diorganyl derivatives are monomeric. Mass spectroscopic data of the compounds show them to be monomeric in the vapor phase

The new compound BaSb 3 has been prepared and its structure determined. It crystallizes monoclinic (C 2/m, a = 1080.7(5) pm, b = 851.9(5) pm, c = 647.1(5) pm, β = 112.66(4)°). The Sb-atoms build up 14-rings of two-and threebonded Sb, which are connected to puckered nets.

Na 3 AsS 4 • 8 H 2 O crystallizes in the space group P2 1 /c with the cell parameters a = 865,1(3), b = 1299,5(4), c = 1359,6(5) pm, β = 102,77(7)°. The cell contains 4 formula units. The structure found consists of tetrahedral AsS 4 -groups and Na-Ions, octahedrally coordinated by water molecules and/or sulfur atoms

The X-ray crystal structure of heptachloro- (triphenylphosphazenyl)cyclotetraphosphazatetraene N 4 P 4 Cl 7 (NPPh 3 ) reveals a novel conformation (tending to Type III) of the triphenylphosphazenyl group with respect to the adjacent ring segment. This observation is contrasted with the structure of N 3 P 3 Cl 5 (NPPh 3 ) where a Type I conformation is observed

The ligand exchange on nonamethylimidodiphosphoramide (NIPA) complexes is found to be very slow comparatively to analogous monodentate ligands; the rates determined by 1 H or 31 P NMR spectroscopy are: k(25°C)=4.3 × 10 -2 s -1 ; 31.6 s -1 • M -1 ; 3.7 × 10 4 S -1 • M -1 and 1.35 × 104 s -1 · M -1 for Mg 2+ , Ca 2+ , Sr 2+ and Li + cations respectively. For the Al 3+ , Ga 3+ , In 3+ and Be 2+ ions no exchange could be detected by 1 H NMR spectroscopy up to 120 °C, indicating rates lower than about 10 -3 s -1

Decomposition of sodium trichloroacetate in an autoclave yields mainly trichloroacetyl chloride (80%) at 180-200 °C. Carbon tetrachloride, chloroform, and perchloroacetic anhydride are minor products. Only traces of phosgene are formed. These arise from decomposition of perchloroacetic anhydride at temperatures above 200-220 °C (equation (5)). Phosgene is not formed in normal phase transfer catalytic reactions

The epoxide-ring of (+)-5-[trans-(Z)-2,3- epoxy-1-methoxy-propylidene]-4-methoxy- 2(5H)-furanone (1) was opened hydrogenolytically (palladium/charcoal) to (+)-(2S)-5-(2-hydroxy-1-methoxy-3-phenylpropylidene)- 4-methoxy-2(5H)-furanone (2) whose absolute configuration (2S) was determined applying Horeau's method. For the natural product (+)-1 itself follows (2S,3R) Reconfiguration