Volume 32, Issue 9

A series of N-chlorosilyl triorganophosphine imines have been prepared by transsilylation reactions of the corresponding N-trimethylsilyl triorganophosphine imines with halosilanes. The new compounds were characterized by elemental analyses, molecular weight determinations, IR and 1 H and 31 P NMR spectra.

29 Si, 31 P and, in part, 13 C NMR data are reported for N-trimethylsilyl-triorganophosphine imines as well as some siliconsubstituted methoxy and chloro derivatives. The spin-spin splitting pattern of the 29 Si{ 1 H} spectra is discussed for disilanes of the type (RR′R″P=N-SiMe 2 -) 2 . A qualitative interpretation of 29 Si chemical shifts is preferably being based on hyperconjugation rather than a (p-d)n bonding mechanism. The preparation of a series of bis(phosphinimino)silanes and 1,2-bis(phosphinimino)disilanes is described.

TlPbI 3 , which is prepared from PbI 2 and TlI by the BRIDGMAN-STOCKBARGER technique, crystallizes in the orthorhombic space group Cmcm with a = 4.625(2), b = 14.885(4), c = 11.857(4) Å, Z = 4. Tl 4 PbI 6 is prepared from PbI 2 and TlI in n/10 HCl under hydrothermal conditions. The compound crystallizes in the orthorhombic space group Pbam with a = 19.117(9), b = 9.877(9), c = 4.586(4) Å, Z = 2. Both structures were solved by direct methods. Both compounds contain PbI 6 -octahedra which are found in PbI 2 and the structural elements of TlI

Cl 6 B 3 N 3 H 6 has been prepared by reaction of gaseous HCl with B-trichloroborazine in benzene. The compound crystallizes in the orthorhombic space group Pnma and four formula units in the cell. The structure was refined by least squares analysis to a R-value of 0.033. The molecules show a nearly ideal chair conformation. Interatomic distances (mean values) are: B-Cl 1.845 and B-N 1.575 Å.

CaCuGe crystallizes orthorhombic, Pna2 1 with a = 2136 ± 2 pm, b = 754 ± 1 pm, c = 435 ± 1 pm, z = 12. The Cu atoms together with the Ge atoms form puckered layers parallel to the b/c-plane. Within each layer each Cu atom is bonded to three Ge atoms and viceversa. Between the layers the Ca atoms are located.

By careful hydrolysis of B(OCH 3 ) 3 in the presence of NaOCH 3 in absolute methanol, crystallized Na[B(OCH 3 ) 4 ] · CH 3 OH · 1.5 H 2 O has been prepared. The properties, IR, NMR spectra and X-ray parameters (P bca ; a = 18.2; b = 13.7; c = 19.5 Å; D 25 exp = 1.2 g/cm 3 ) are described. The crystal structure was determined by single crystal diffractometer data and refined to a conventional R value of 4.5.

By Mössbauer spectroscopy the cubic compound CsFe(CN)3, α = 5.20 8 Å, is shown to contain high and low spin iron(II) in 1:1 proportion independant of temperature 4.2 ≦ T ≦ 600 K. This gives evidence of isomorphism with the elpasolite Cs 2 MgFe(CN) 6 . The quadrupol splitting of the high spin iron(II) spectra strongly depends on temperature and vanishes beyond 400 K. This behaviour is interpreted in terms of static Jahn Teller distortion in the low temperature range, also indicated by the splitting of the IR absorption associated with the Fe-N stretching frequency. The data of Mössbauer and IR spectra, as well as of magnetic susceptibility measurements are given and discussed.

The photolysis of (η 5 -C 5 H 5 )M(CO) 3 CH 3 complexes (M = Cr, Mo, W) in solvents such as pentane, benzene or tetrahydrofuran results in cleavage of the methyl-metal sigma-bond and formation of the corresponding [(η 5 -C 5 H 5 )M(CO) 3 ] 2 analogs as well as methane. Deuterium labeling studies indicate that, for the molybdenum system, abstraction of a hydrogen atom from a cyclopentadienyl ring by the methyl group represents a major reaction pathway for the production of methane. Photolysis of (η 5 -C 5 H 5 )M(CO) 3 CH 3 complexes in CHCl 3 produces high yields of [(η 5 -C 5 H 5 )CrCl 2 ] 2 in the case of the chromium analog, or (η 5 -C 5 H 5 )M(CO) 3 Cl where M = Mo or W.

The title complex was synthesised and its structure determined by x-ray crystallography. The structure contains two hydrogen bonds between the phosphoryl oxygen atom and the two meta-toluidinium ions. The P–N bond lengths are significantly different and the differences, attributed to varying p π-d π interactions along the bonds, confirm earlier observations on tri-para-toluidylphosphazenyl oxide.

The chemistry of bis(trimethylsilyl)aminoisocyanide (1) is determined by three reactive centres of the system : the hydrolyzable Si–N-bond, the oxidizable carbon in the formal oxidation state two, the additionable double bond system. Reactions of the oxygen stable compound 1 with halogens X 2 or sulfenyl halides RSX as oxidizing agents gives compounds of type (Me 3 Si) 2 NNCX 2 or (Me 3 Si) 2 NNCX(SR). Heterocumulenes such as CO 2 , CS 2 , RNCS (R = (Me 3 Si) 2 N), SO 2 add to 1, leading to heterocycles, which decompose at higher temperatures by ring cleavage. With other heterocumulenes such as PhNCO, Me 3 SiNSO, Me 3 SiNSNSiMe 3 products are found, the formation of which could be explained by reaction paths including the building and cleavage of heterocycles.

The synthesis of binuclear iron and chromium complexes with bridging dppe ligands is reported, e.g. [μ-dppe{C 5 H 5 Fe(CO)Br} 2 ] or [μ-dppe{C 5 H 5 Cr(CO)(NO)} 2 ], (dppe = (C 6 H 5 ) 2 PC 2 H 4 P(C 6 H 5 ) 2 ). With hydrazine, these compounds yield no doubly bridged complexes with dppe and N 2 H 4 bridges, neither in dark- nor in photo-reactions. In case of the iron complexes either reduction of the starting complex or transformation of the dppe bridging ligand into a chelating ligand are observed instead. The reactions depend upon the polarity of the solvent and yield [μ-dppe{C 5 H 5 Fe(CO)}2] in benzene, however, [C 5 H 5 Fe(CO)(dppe)]Br in tetrahydrofuran. The chromium complex undergoes decomposition on UV irradiation, splitting off CO and yielding the chelate complex [C 5 H 5 Cr(NO)(dppe)] as well as polymeric [C 5 H 5 Cr(NO)]x.

Rare earth oxychlorides crystallizing in the SmSI arrangement undergo a high pressure transformation to a PbFCl-type structure. An intermediate phase appearing during the transition supports a proposed mechanism of displacive and martensitic movements in several steps. The decomposition of PbFCl-type oxychlorides to new Ln 3 O 4 Cl compounds is discussed as a topotactic reaction.

Reactions of tetrakis(acetoxymercuri)methanes C(HgOOCCR 3 ) 4 (R = H, or F) in aqueous solutions with methylsulfane CH 3 SH, or sulfane H 2 S, yield tetrakis(methylthiomercuri)methane C(HgSCH 3 ) 4 , and μ-dithiotetramercurimethane CHg 4 S 2 , respectively, both insoluble in common solvents and thermally remarkably stable. The central CHg 4 groups of the starting materials have been preserved under the reaction conditions, thus tetrahedral entities C(HgS–) 4 are common to both compounds. In the polymeric, amorphous CHg 4 S 2 the CHg 4 units are linked by sulfur bridges in a highly disordered manner, as is suggested by vibrational spectra. In other respects close similarities in the vibrational behaviour of these CHg 4 fragments and of the isosteric NHg 4 tetrahedra in tetramercurioammonium complexes have been observed.

In order to improve the poor yield of the vanadocene and chromocene syntheses VCl 2 · 2 THF has been prepared by reduction of VCl 3 · 3 THF with zinc and CrCl 2 · THF by action of hydrogen chloride on chromium. The metal(II) chlorides have been reacted with sodium methylcyclopentadienide and perdeuterocyclopentadienide to give the corresponding vanadocenes and chromocenes in yields up to 68% and 85%, respectively. The products have been characterized by paramagnetic 13 C, 1 H, and 2 H NMR the latter being newly introduced in the class of organometallic π-radicals.

The 15 N-labeled diazadiphosphetidine (3a) was prepared to confirm the proposed ring structure by 1 H, 31 P, 13 C, and 15 N NMR spectroscopy. The temperature dependence of the NMR spectra suggests a dissociation equilibrium which could be verified by an exchange reaction.

H NMR spectra of different hydration stages show that the water molecules in hydrated layered niobium sulfides A 0.5 (H 2 O) y [NbS 2 ] are rather mobile at room temperature. A structural scheme of water arrangement in the interlayer space is proposed with the C 2 -axis of the H 2 O molecules parallel to the basal planes of the NbS 2 layer units.

The efficiency of the 2-oxazoline system as a protecting group for the sterically hindered carboxyl function is demonstrated in the case of Grignard-reactions of certain organophosphorus compounds. Thereby, organophosphorus species with an o-carboxyphenyl group are easily accessible. Additionally, the enantiomer separation of an unsymmetrically substituted tertiary phosphine oxide with an o-carboxyphenyl group is described.

The reaction of the spin-labeled diimidazolide 1 with hydroxy and amino compounds was studied. Diimidazolide 1 was superior to the dichloridate 6 for the preparation of spinlabeled phosphates 3 and phosphorodiamidates 2. The spin-labeled phosphate 15 was synthesized through hydrolysis of 6. Spin-labeled cyclophosphoramidates (10-13), analogs of the cytotoxic Endoxan, were prepared by the reaction of 1 and 6 with the appropriate difunctional nucleophile. Inductive effects of substituents in the imidazolyl moiety on the transphosphorylation reaction were also studied. [xxx]

In the γ-radiolysis of deoxygenated, N 2 O-saturated aqueous solutions of maltose, lactose, gentiobiose, melibiose, trehalose and sucrose carbohydrate products containing five or six carbon atoms have been identified and their G-values measured. These products originate from the OH radical induced scission of the glycosidic bond of the disaccharides. The nature of the products is in agreement with a reaction scheme proposed previously for the radical induced scission of the glycosidic bond of cellobiose. It involves hydrolysis and the rearrangements of radicals with the free spin next to the glycosidic bond and to the lactol bridge. The nature the glycosidic bond (α, β, 1-4, 1-6, 1-1, 1, 2) has only little influence on the G-values of its scission which range between about 1.9 and 3.5.

The syntheses of the above biologically active esters are described. By NMR spectroscopy it is shown that the corresponding ethyl compound 4 may exist in both the trans and the cis conformers. Starting with 4, addition of an appropriate alcohol results in the corresponding 4-alkoxy compound of 4. The described esters are antagonists of aspartic acid as well as of oxalacetic acid and inhibited the growth of E. coli MRE 600.

3-(3,4-Dimethoxyphenyl)-1-methyl-1,5,6,7-tetrahydro-4H-indazol-4-one (1) is reduced to 2 a. Dehydration of 2 a gives 3 which is hydrogenated to 4 or dehydrogenated to 5. Regiospecific bromination of 1 gives the bromoketones 6 or 7, the latter is transformed into the phenol 11 a or into the indazoloquinone 13 which is brominated to 14 and converted into the aminoquinone 15.

Reaction of active methylene compounds (2,4-pentanedione, dimedone, 4-hydroxycoumarin, 4-hydroxycarbostyriles) with triethyl orthoformate and primary amines (aniline, o-methylmercapto aniline, cyclohexylamine) yields substituted aminomethylen-1.3-dicarbonyles (1-5), which in their tautomeric form (B) give stable, deeply coloured Cu··- and Ni- --organic complexes (6-27). The same chelates may also be obtained by direct reaction of orthoformate, amine and active methylene in the presence of the metal acetate at 40-50 °C in 65-90% yield. Anilinomethylene-3-methyl-1-phenylpyrazolone in turn does not exhibit any tendency to chelate Cu·· or Ni··. The X-ray crystallography of its o-methylmercaptoderivative shows it to exist in the virtually planar enamin form.

Condensation of benzoin and pyrocatchol gave 7-hydroxy-2,3-diphenylbenzofuran (1a), which on oxidation yielded the quinone 3a whereas, its methyl ether 1b gave the benzophenone 2a on oxidation. Nitration of 1a and 1b led to the formation 4,6-dinitro- (1c) and 4-nitro (1h) derivatives,respectively, also bromination of 1a and 1b gave 4,6-dibromo- (1f) and 6 -bromo- (1j), respectively

Crystals of LiCo[(R,S)-EDDS] • 3 H 2 O have been synthetized and its structure was determined by X-ray analysis. Monoclinic, α = 9.624, b = 12.788, c = 12.049 Å, β = 94.85°, space group P2 1 /c. The crystal consists of binuclear units Co 2 [(R,S)-EDDS] 2 2 -. The central ethylenediamine chelate ring has an envelope conformation.

The description of substituent dependence of 29 Si NMR chemical shifts by means of pairwise interaction parameters is interpreted with a simple quantumchemical model theoretically.

Single crystals of AgGdF 4 have been investigated by X-ray methods. AgGdF 4 is hexagonal (isostructural to NaNdF 4 ) with a = 6.233, c = 3.599 Å, Z, = 3/2. Guinierphotographs give the same structure for AgLnF 4 -compounds with Ln = Nd, Sm-Ho. The other five (Ln = Er-Lu, Y) crystallize trigonal (isostructural to KErF 4 ) in a superstructure variant of the CaF 2 -type (Z = 18).

Bis(trimethylsilyl)peroxide was used as a reagent to prepare a novel ring system, 1-aza-3,4-dioxa-2,5-diborolidin by reaction with an appropriate diborylamine. No ring systems containing the peroxo group were obtained when oxidation predominates as shown for BBr 3 and CH 3 BBr 2 .

Sr 5 Sn 3 and Ba 5 Sn 3 crystallize tetragonally in the Cr 5 B 3 structure type with the following constants : Sr 5 Sn 3 : α = 854(1) pm, c = 1606(2) pm, c/α = 1.88, Ba 5 Sn 3 : α = 902(1) pm, c = 1678(2) pm, c/α = 1.86.

The title compounds were prepared by annealing the elements in stoichiometric proportions at 720 °C as well as by thermal decomposition of Cu 3 PS 4 or Cu 3 PSe 4 . They crystallize in the space group P2 1 3 with lattice parameters a = 9.671(1) and 10.116(1) Å resp.; X-ray powder diffraction data are listed.

Diadamantyldioxetane, trim ethyldioxetane and tetram ethyldioxetane were photolyzed b y light of A > 260 nm . The spectral distribution o f the quanta emitted during photoinduced decom position of dioxatenes was found to be different from fluorescence and phosphorescence o f ketones. Flash photolysis experim ents showed the absorption of an short-lived interm ediate. It was concluded, therefore, that photolysis o fdioxetanes is not a concerted process but involves at least one precursor o f the final product ketone.