Volume 32, Issue 5

1 H, 13 C, 29 Si NMR and 35,37 Cl NQR spectra have been obtained for (chloromethyl)silane, H 3 SiCH 2 Cl. The results are compared with the corresponding parameters of ethyl chloride, H 3 CCH 2 Cl. A less polar C—Cl bond is found in the silicon compound, due to the electronic effect of the silyl group H 3 Si. Previous findings are in agreement with this conclusion.

2,4-Dialkoxy-diazadiphosphetidines and 2-chloro-4-alkoxydiazadiphosphetidines are formed as pure cis isomers (2) and trans isomers (4) from 2,4-dichloro-diazadiphosphetidine (1). In contrast to 4, compounds 2 show isomerisation into a mixture of cis and trans isomers 2 and 3 on standing in solution. No isomerisation was observed for 3, R = tert-BuO, whereas only a mixture of isomeres 5 and 6 could be isolated with this mixed alkoxy compound.

S 4 N 4 reacts at 25 °C with trifluoro and trichloro acetic acid anhydride, respectively, to yield yellow crystalline CX 3 –CO–NS 3 N 2 (X = F, Cl), the mass, infrared, and Raman spectra of which are reported. An X-ray structure analysis of monoclinic CF 3 CONS 3 N 2 revealed a non-planar five-membered S 3 N 2 ring containing an unusually long (2.206 A) sulfur-sulfur bond with one sulfur atom additionally connected to an exocyclic nitrogen atom by a multiple bond. Comparisons with the infrared spectra of S 3 N 2 O and ten compounds of type RNS 3 N 2 allowed to identify four wavenumbers characteristic for the S 3 N 2 ring. The relationship μ = 23.09d-27.27 has been derived for stretching vibrational wavelengths, μ (in μm), and bond distances, d (in Å), of sulfur-nitrogen bonds.

Single crystals of 1—x Ho 2 O 3 : xCaO (x = 0.07), CaHoO 2.5 (A) and Ca 0.5 Ho 1.5 O 2.75 (B) were prepared by high temperature reaction and investigated with X-ray single crystal data. It can be shown that small amounts of CaO stabilize the monoclinic B-Typ of rare earth oxides. Phase (A) and (B) cannot be seen as a stabilized B-type crystal because they have an new crystal structure with space group C 2 2h –P 2 1 /m, a = 656.6, b = 356.7, c = 529.4 pm, β = 92.3°; a = 650.2, b = 352.4, c = 584.5, β = 92.3°.

Formation, structure, vibrational spectrum and some chemical properties of the title compound are described.

The Mössbauer effect of 57 Fe has been studied in the series of compounds Vi 1-x Fe x O 2 for very low Fe concentrations between 4.2 and 500 K. Three insulating phases are clearly distinguished. In the low temperature M 1 -phase only one Fe-site is seen for x ≦ 0.0026 in accordance with the insulating phase of VO 2 . But for higher Fe concentrations, x ≧ 0.006, two iron sites can be resolved by their electric field gradients in the M 1 -phase. The Debye-Waller factor shows an anomalous behaviour for both iron concentrations in the M 1 -phase.

The 31 P-chemical shifts of trimethylsilicon-, -germanium-, and -tinphosphines of the type [(CH 3 ) 3 E] n PR 3-n (E = Si, Ge, Sn; R = H, t C 4 Η 9 , C 6 H 5 ; n = 0, 1, 2, 3) are reported and discussed.

Chemical and structural data of numerous bis(α,β-dionedioximato)metal(II) compounds are summarized. All of them crystallize in columns but principally two different kinds of molecular arrangements occur in the solids. In one phase the molecular planes are inclined to the direction of the linear metal chains with an angle different from 90°. This allows only indirect interactions between the metal ions via the ligand. (“M—L—M” stacking.) The other modification consists of molecules with their planes perpendicular to the M—M-chains. This form allows direct metal-metal contacts (“M—M” modification). Depending on a few molecular parameters a “M—L—M” or a “M—M” stacking is obtained upon crystallization. Since for those compounds which could be isolated in both modifications the M—L—M form has the higher density it is concluded that only stronger M—M interactions stabilize the less dense M—M forms. A wide range of metal-metal separations with a lower limit of 3.15 Å in mixed valence systems are found in different “M—M” compounds. In any case the intrachain metal-metal distances are reduced considerably upon oxidation of the bivalent complex molecules. The influence of “electronic” and “sterical” parameters of the complex molecules on the intermolecular metal interactions and on the type of columns in the solid state is discussed.

The phosphine complexes Co(PR 3 ) 2 X 2 (X = Cl, Br; R = Et, Ph, C 6 H 11 ) react with furoylazide (furN 3 ) at 25 °C to give the phosphinimine compounds Co(furN=PR 3 ) 2 X 2 . At lower temperatures the intermediate complex Co[furN 3 P(C 6 H 11 )3]Br 2 • Et 2 O with phosphatriazene as ligand could be isolated.

The preparation of complexes containing 1,2,4-triazole (trz) is described. The general formula is M(trz) 2 (CNS) 2 with M = Mn, Fe, Co, Ni, Cu and Zn. For M = Ni two isomeric compounds have been isolated. The infrared spectra of the Ni compounds are assigned on the basis of the assignment for the free 1,2,4-triazole. One of the Ni compounds is a trinuclear complex according to its infrared spectrum. The other complexes are isomorphous, with exception perhaps of the Cu complex. For these compounds a polynuclear structure is proposed.

Fluorosilanes react with lithium amides and organolithium compounds to give aminofluorosilanes and organofluorosilanes. The reactivity of the monoaminofluorosilanes with butyllithium is decreasing with increasing size of the substituents and with their stabilisation in the molecule. Reactions observed include: a) (2 + 2) cycloaddition, b) ring closure under either C–H-cleavage or under migration of a methanideion and c) formation of stable lithio-aminofluorosilanes.

Dichloroxozirconium(IV) octahydrate reacts with acetyl, propionyl, butyryl and chloracetyl chlorides at low temperatures to form addition compounds of the parent carboxylic acid, ZrOCl 2 · 2 RCO 2 H, but at higher temperatures the corresponding carboxylates of the type ZrO(RCO 2 ) 2 · RCO 2 H are obtained. Benzoyl chloride does not react at low temperatures, but at 60 °C gives an addition product ZrOCl 2 · 2 C 6 H 5 CO 2 H, and at higher temperatures a substitution product ZrO(C 6 H 5 CO 2 ) 2 · 2 C 6 H 5 CO 2 H is obtained. Elemental analyses, molar conductance measurements, infrared spectral studies and thermal decompositions have been carried out to understand the nature of these compounds.

The formation of the 1:1 complexes of Mg 2+ , Ca 2+ , Ni 2+ , Cu 2+ and Zn 2+ with tris-(dihydroxy-phosphonylmethyl)phosphine oxide has been studied by pH measurements. The values of the stability constants and their trend is similar to that found for the complexes of tripolyphosphate.

Copper(II) complexes with the Schiff bases formed by condensing t-butyl-, isopropyl-, cyclohexyl- and diphenylmethylamines with salicylaldehyde and 3-methoxy- and 5-nitrosalicyl-aldehyde have been prepared and characterized. The isotropic nuclear hyperfine coupling constants increase in the order t-butyl < isopropyl < cyclohexyl < diphenylmethyl for the N-substituents in the three series of complexes while isotropic g-values increased in the opposite direction. Spectra structure correlations were examined and discussed.

On the basis of NMR spectroscopy ( 1 H and 13 C) it can be shown that in water, dimethylsulfoxide and p-dioxane only the tautomer 1 of L-ascorbic acid is found in a measurable amount. Upon formation of the mono-anion la deprotonation occurs on the hydroxyl group attached to C-3; in addition the hydroxyl group on C-2 is deprotonated in case of the di-anion 1b. Both anions do not open the lactone ring. After oxidation with iodine in aqueous solution only the dimer of dehydroascorbic acid is detected. This is hydrolized with a half-life of three hours to the monomeric dehydro ascorbic acid dihydrate 7. In dimethylsulfoxide the oxidation rate is decreased, and therefore the formation of the monomeric non-hydratized dehydroascorbic acid 10 can be monitored. This undergoes ringclosure relatively fast to give the half-ketal 13, the reaction of which via 14 leads to the optical active dimeric dehydroascorbic acid 6. The L-ascorbic acid acetonide 15 is oxidised by iodine to 16 which undergoes racemization via the enol 17 to give 18. This forms an equilibrium with compound 19.

3-Hydrazinophenanthro[9,10-e]-1,2,4-triazine (2) was prepared and condensed with aromatic aldehydes to give the corresponding arylidene derivatives (3 a–f). Phenanthro-[9,10-e]-1,2,4-triazolo[4,5-b]-as-triazine (11), its 3-mercapto- (4 a), 3-alkylmercapto- (9 a–d) and 3-hydroxy- (4b) derivatives were prepared and their structures have been established.

The helium charge exchange and the isobutane chemical ionization spectra of 4-methoxy cyclohexanecarboxylic acid ethyl esters (1 c and 1 t ), 2,6-dimethyl-4-hydroxytetrahydropyranes (2 c and 2 t ), 2,4,6-trimethyl-4-hydroxytetrahydropyranes (8 c and 3 t ), and 2,7-dimethoxy-cis-decalins (4 c and 4 t ) have been screened for correlations with the stereochemistry of these molecules. From these data it appears that chemical ionization is especially suited for configurational assignments in epimeric molecules.

The autocatalytic effect of the reduction products of some selected Schiff bases on their reduction on copper and lead cathodes was investigated. The repitition of reduction efficiency measurements in the same solution and the pre-treatment of the cathode or the solution by electrolysis confirmed the autocatalytic effect of the produced secondary amines. Different amines were tested as external catalysts.

The preparation and enantiomer separation of an unsymmetrically substituted thiophosphinic acid, t butyl-phenylthiophosphinic acid (1), is reported. Reaction of 1 with PCl 5 and SOCl 2 yield the corresponding thiophosphinyl chloride and phosphinyl chloride, respectively.

The preparation and separation into diastereomers of t butyl-phenyl-phosphinic acid (—)-menthyl ester (1a) is reported. The diastereomeric purity as well as the absolute configuration at phosphorus of 1 a can be deduced from the detailed analysis of the 1 H NMR spectra of samples of 1a differing in their diastereomer ratios.

The preparation of the hitherto unknown bromo-elpasolites Cs 2 BLnBr 6 (B = Na, K; Ln = Sc, Tm, Sm) is reported. Besides Cs 2 KSmBr 6 they all crystallize cubic-face centered, isostructural to K 2 NaAlF 6 (elpasolite).

The new compounds R 3 Si-O-NSOF 2 and R 3 Si-O-N(SiR 3 )POF 2 [R = CH 3 ] are obtained by cleavage reaction of Si-N-bonds in tris(trimethylsilyl)hydroxylamine by OSF 4 and OPF 3 , respectively.

The catalytical system, prepared from H 2 PtCl 6 + SnCl 2 · 2 H 2 O and the additives HBr and H 2 O in iso-butanol is very efficient for homogeneous hydrogenation of unsaturated esters under mild conditions. Reaction rates r up to 40 mMol · 1 -1 · min -1 and turnover numbers UZ higher than 1.600 are observed.

Hexafluoroacetone and tetramethyldiphosphine react readily at low temperatures producing three 4,4-bis(trifluoromethyl)-1,2-oxaphosphetanes (1), (2), and (3). The compounds have chiral centres at phosphorus producing doubling of resonances in the NMR spectra.

Single crystals of [Cu(salalgly) (tu)] have been prepared. From a complete X-ray structure determination follows the square pyramidal structure of this magnetically diluted copprr(II) complex. The S-donor atom of thiourea is short bonded to the central atom, Cu ↔ S = 2.27 Å, “in plane”.

From (chloromethyl)silane and trimethylphosphine a phosphonium salt [(CH 3 ) 3 P–CH 2 SiH 3 ]Cl is obtained, which can be converted into the ylide (CH 3 ) 3 P=CHSiH 3 upon transylidation with (CH 3 ) 3 P = CH 2 . The silyl ylide is thermally unstable and looses hydrogen to give the title six-membered ring species.

The literature is replete with reports on furo- 1,2 and thieno-(2,3-b)quinoline 2 syntheses. But hitherto, there is only one report on the selenium 3 and no report on the tellurium analogs. In connection with our work 1,2 on furo(2,3-b)quinolines, we prepared several 3-(2′-hydroxyethyl)-2-quinolones and we felt that it might be possible to transform them, by an appropriate sequence, into the corresponding selenolo- and tellurolo-(2,3-b)-quinolines. Recently we have reported 3 the synthesis of several 2,3-dihydroselenolo-(2,3-b)quinolines, achieved through the use of 2-chloro-3-(2′-chloroethyl)quinolines, obtained from the corresponding 3-(2′-hydroxyethyl)-2-quinolones by POCl 3 -treatment. Simultaneously we were exploring the feasibility of obtaining the tellurium analogs in a similar fashion.

Trapping reactions of bis(trifluoromethyl) substituted nitrile ylides with azobenzene yielding 5,5-bis(trifluoromethyl)-Δ 3 -1,2,4-triazolines are described.