Volume 40, Issue 8

W 2 NCl 9 was obtained as a brilliant red crystal powder from tungsten hexachloride and tris(trimethylsilyl)amine. According to its IR spectrum it has dimeric molecules [W 2 NCl 9 ] 2 with bridging chlorine atoms. Its reaction with tetraphenylphosphonium chloride yields PPh 4 [W 2 NCl 10 ], and with phosphorus oxide chloride W 2 NCl 9 ·OPCl 3 is obtained; both are soluble in dichlorom ethane. The crystal structure of PPh 4 [W 2 NCl 10 ] was determined by X-ray diffraction (2521 observed reflexions. R = 0.065). Crystal data: triclinic, space group P1̄, Z = 2, a = 1125.7, b - 1278.2, c = 1347.8 pm, α = 110.08, β = 94.55, γ = 111.55°. The structure consists of PPh4 ⓛ ions which are arranged to (PPh 4 ⓛ ) 2 pairs about inversion centres, and of [W 2 NCl 10 ] ⃝ anions. The latter possess an almost linear W NW group (173°) with slightly different WN bond lengths of 179 and 188 pm corresponding to double bonds. Each tungsten atom has an octahedral coordination. The WCl bonds trans to the nitrido ligand are about 9 pm longer than the bonds in the cis positions.

The title compound results from a slow reaction between two m oles of PPh 4 [W 2 NCl 10 ], dissolved in dichlorom ethane, upon addition of carbon tetrachloride. The red crystals are characterized by X-ray diffraction. (PPh 4 ) 2 [W 3 N 2 Cl 14 ] · CCl 4 · CH 2 Cl 2 crystallizes triclinically in the space group P1̄ with two formula units per unit cell. The cell dimensions at -100 °C are: a = 1430, b = 1462, c = 1655 pm , α = 74.6°, β = 79.0°, γ = 82.4° (10,908 independent, observed reflexions, R = 0.078). The structure consists of PPh 4 ⊕ ions, trinuclear finitrido anions [W 3 N 2 Cl 14 ] 2⊝ and enclosed molecules of CCl 4 and CH 2 Cl 2 . The tungsten atom s of the anion are linked by almost linear nitrido bridges ( ~ 176°) with different WN bond lengths (mean values 184 pm and 207 pm ), corresponding to double and single bonds. The equatorial WCl 4 groups are in eclipsed conformation; the two chlorine atoms in trans-position to the nitrido groups have mean bond lengths of 240 pm which is 9 pm longer than the equatorial W -Cl bonds. The IR spectrum is reported.

Potassium disilanyl, KSi 2 H 5 , 2-potassium trisilanyl, KSiH(SiH 3 ) 2 , and 2-potassium isotetrasilanyl, KSi(SiH 3 ) 3 , are formed in the reactions of potassium silyl. KSiH 3 , with di-, tri-, n-tetra-, /so-tetra- and pentasilane, respectively. The simultaneous formation of potassium hydride can be almost completely avoided by carrying out the reactions in very diluted solution. The product mixtures formed have been analyzed by gas chromatography after reaction with benzylchloride, potassium hydride then giving toluene. A mechanism for the stepwise formation of the various higher potassium silanyls is discussed.

NEt 4 [SiSCl 3 ] · 0.5CCl 4 was obtained from NEt 4 SH and SiCl 4 in liquid H 2 S and subsequent crystallization from CH 2 Cl 2 /CCl 4 . The analogous reaction with GeCl 4 was performed without solvent at room temperature. Raman and IR spectra are in accord with simple anionic species with C 3v symmetry. The crystal structure of NEt 4 [SiSCl 3 ] · 0.5 CCl 4 was determined from X-ray diffraction data (849 independent observed reflexions, R - 0.030). Crystal data: tetragonal, space group P4̄c2 , Z = 4, a = 1196.0, c = 1200.7 pm. Both, cation and anion occupy positions on twofold rotation axes, with the consequence of positional disorder for the [SiSCl 3 ] - ion by statistical superposition of the sulfur and one chlorine position. The general packing of cations and anions resembles the NaCl type, the CCl 4 molecules occupying interstices. NEt 4 [GeSCl 3 ] · 0.5 CCl 4 is isotypic (a = 1204, c = 1201 pm); NEt 4 [GeSCl 3 ] also crystallizes in the tetragonal system (a = 1048.4, c = 1274.4 pm).

[Sr(en) 4 ] 2 (As 3 Se 6 )Cl 1 has been prepared by the reaction of SrCl 2 with As 2 Se 3 in ethylenediamine solution under reflux and its structure established by X-ray structural analysis. 1 contains discrete cyclic As 3 Se 6 3- anions with a six-membered As 3 Se 3 -ring in the chair conformation. A bridging ethylenediamine molecule leads to the formation of [Sr(en) 4 ] n chains for the first of the Sr cations. In contrast, discrete Sr(en) 4 units are observed for the second cation.

The nature of the products which are formed in the reaction of tris(trimethylsilyl)Methylfluorosilanes (Me 3 Si) 3 C -SiF 2 R with KOH depends on the bulkiness of the substituents R. The condensed siloxane is obtained for R = F . The crystal structure determination of this siloxane (Me 3 Si) 3 C -SiF 2 -O -SiF 2 -C (SiMe 3 ) 3 shows that the Si -O - Si unit is linear. A fluorosilanol as well as a siloxane could be isolated for R = Me. 1,3-Migration of one or two trimethylsilyl groups from the carbon to the oxygen takes place for R = phenyl, rm-butyl or silylamine, with formation of siloxanes which are isomeres o f the expected silanols.

The reaction between (triphenylphosphine)acetatogold(I) and concentrated sulphuric acid in methanol leads to (Ph 3 PAu) 2 SO 4 (1) or [(Ph 3 PAu) 3O ] + HSO 4 - , depending on the acid concentration. The crystal structure of the methanol solvate of (1) was determined [C2/c, a = 1348.3(2), b = 1451.0(2), c = 1853.8(3) pm, β = 99.90(2)°, Z = 4, R = 0.037 for 3138 unique observed reflections], 1 possesses crystallographic twofold symmetry, with Au -O 206.3, Au -P 221.6 pm. The corresponding selenate is isomorphous.

Bis(dipyridiniomethan)-di-μ-iodotetraiododicuprate(I), [Py 2 CH 2 ] 2 [Cu 2 I 6 ] and two modifications of bis(tetraphenylphosphonium )-di-μ-iodo-diiododicuprate(I) were obtained by reacting Cu with I 2 and [Py 2 CH 2 ]I 2 or [PPh 4 ]I in acetone. The crystal structures of these com pounds are built up by the cations and the binuclear anions: edge sharing Cul 4 -tetrahedra in [Cu 2 I 6 ] 4- and edge sharing, nearly trigonal planar Cul 3 -units in [Cu 2 I 4 ] 2- . Whereas the Cu 2 I 4 anions (-A ) are centrosymmetric and almost planar, the anions (-B) are folded about the bridging I···I contact. The anions [Cu 2 I 6 ] are in intimate contact with the cations via short intermolecular I···N and I···C interactions.

The iminovanadium (V) com pounds t C 4 H 9 N = V(N t C 4 H 9 -SiMe 2 -NH t C 4 H 9 )Cl 2 (3) and [VCl(μ-Cl)(N t C 4 H 9 )(NH t C 4 H 9 )(NH 2 t C 4 H 9 )] 2 have been prepared by reaction of Me 2 Si(NH t C 4 H 9 ) 2 with VO(OC 2 H 5 )Cl 2 and VO(O t C 3 H 7 )Cl 2 , respectively. 3 was investigated by 1 H , 51 V NMR spectroscopy and X-ray diffraction analysis; the structure has been found to be a mononuclear vanadium complex with a distorted trigonal bipyramidal arrangement of the ligands.

The reaction of antimony(III)-chloride with lithiumdiisopropylamide in the molar ratio 1:2 in ether gives monochloro-bis(diisopropylamino)stibane (4). m -Bromophenyl-bis(diisopropylamino)stibane (2a) is prepared by reaction of m-bromophenyllithium with 4. p-Bromophenylbis(diisopropylamino)stibane (2b) can be obtained by reaction of p-brom ophenyl-dichlorostibane with lithium-diisopropylamide, or from p-brom ophenyllithium and 4. The metal-halogen-exchange of 2a, b by butyllithium in ether gives m- or p-Lithium phenyl-bis(diisopropylamino)- stibane (3a, b), respectively. Without isolation of the lithiated com pound m-/p-phenylene-bis[bis- (diisopropylamino)stibane] (5a, b) are prepared by reaction o f 3a, b with 4. Esterification of 5a, b with C 2 H 5 OH (1:4) yields m-/p-phenylene-bis(diethoxystibane) (6a, b). The reaction of 6a, b with acetylchloride in chloroform gives m -/p-phenylene-bis(dichlorostibane) (7a, b). The new compounds 2-7 are characterized by elemental analysis, NM R- and IR-spectra. 7a, b are also characterized by MS.

Secondary diaminophosphanes 1c-e as well as alkylaminophosphanes 1g , h are available by the reaction of the corresponding chlorophosphanes with lithium-tetrahydridoaluminate. With triethylamine containing three equivalents of hydrogen fluoride, the aminophosphanes 1d , g are converted into the secondary fluorophosphanes 2a, b. While 1c -e are thermally quite stable, 1f -h and 2a, b decompose to give diphosphanes through elimination of amine and hydrogen fluoride.

Menthyl-substituted phosphorus compounds L-M en(R )P(X )Cl(R = Cl, L-M en, D -Men ; X = :, S) are synthesized. ID and 2 D NMR studies on nuclei 1 H , 13 C and 31 P were used to characterize singular, diastereotopic and enantiotopic menthylgroups.

The ethenedithiolato complex [(CO) 3 FeSCH 2 ] 2 (1) is obtained by thermal fragmentation of thiirane-S-oxide in the presence of Fe 3 (CO) 12 in THF and by photolytic reaction of [(CO) 3 FeS] 2 (3) with ethene, respectively. According to an X-ray structure analysis, complex 1 has the same symmetric polyhedron structure as dihydrobenzvalene 2 .

Transition metal complexes of the ligands 1-thiooxamate and 2-thiooxam ate have been prepared. According to crystal structure analysis of Fe(2-thiox) 2 (H 2 O) 2 , Zn(2-thiox) 2 (H 2 O) and Zn(1-thiox) 2 (H 2 O) 2 these ligands act as O .S-donors and form pentaatomic chelaterings. Both Zn-complexes are trigonal-bipyramidally coordinated.

MoN(N 3 ) 2 Cl(terpy) is formed by the reaction of MoCl 4 (C 2 H 5 CN) 2 with (CH 3 ) 3 SiN 3 and subsequent addition of terpy. This complex appears also as the main product o f the heterogeneous reaction between MoCl 3 (terpy) and (CH 3 ) 3 SiN 3 . It crystallizes in the monoclinic space group P 2 1 /c with the lattice parameters a = 875.5, b = 1041.4, c = 1891.3 pm, β = 97.00°, Z = 4. The central Mo atom is seven-coordinated in the form of a slightly distorted pentagonal bipyramid, the nitrido and chloro ligands being in axial positions. The triply bonded nitrido ligand ( Mo - N 1 = 166.2 pm) causes a strong trans effect, resulting in a long Mo-Cl distance of 271.9 pm.

Aliphatic diazo compounds display different reactivity towards the phosphaalkene 9: diazomethane, diazoethane and terf-butyl diazoacetate (10a-c) formally react with Si/P-insertion to give the hitherto unknown phosphaalkenes 12a-c. In contrast, 1-diazo-2.2-dim ethylpropane (10d) and diazotrimethylsilylmethane (10e) lead to the 1.2.4-diazaphospholes 15 and 17, respectively, if the primary products (11d , 14) are treated with sodium hydroxide in tetrahydrofuran. T he reaction of the nitrile oxides 18a-c with 9 yields the 1.2.4-oxazaphospholes 20a-c; the [3+2] cycloadducts 19a-c are assumed to occur as intermediates, which eliminate hexamethylsiloxane either spontaneously (19a, b) or with OH - -catalysis. Azide dipoles (21a-c) add to 9 with formation of 4.5-dihydro-1.2.3.4-phospholes (22a-c) which - instead of aromatization by hexamethyldisiloxane elimination - prefer fragmentation to 23 (→25 ) and imidoesters 24a-c; hydrolysis produces the pivaloyl amides 26a-c. The 1:2 reaction between 9 and the o-quinones 31a-d proceeds via [4+2] cycloadducts (32a-d) to produce the phosphoranes 34a-d by a subsequent [4+1] cycloaddition process.

The preparation of tetrabenzoporphyrinatocobalt(II) and tetrabenzoporphyrinatocobalt(III)- cyanide derivatives either with terminal or bridging cyanide is described. The IR and the 1 H NMR spectra as well as magnetic measurements are in accordance with the proposed structures and the oxidation states of the complexes. μ-Cyano(tetrabenzoporphyrinato)cobalt(III) (4) exhibits a powder conductivity of σ RT = 4 ·10 -2 S/cm, without additional external doping.

Diethyl-hexadecaphosphane (2) and dimethylhexadecaphosphane (3) have been synthesized by reacting dilithium-hexadecaphosphide, Li 2 P 16 (1 ), with ethylbromide and methylbromide, respectively. 2 and 3 are the first polycyclic organophosphanes with 16 P atoms in the molecule.

[2,3-Bis(diphenylphosphino)m aleicanhydride]- MCl 2 (M = Pd, Pt) reacts with M (PPh 3 ) 4 (M = Pd, Pt) to form paramagnetic, mononuclear complexes of Pd (Pt). It is shown by EPR , IR and X-ray examination, that the unpaired electron is delocalized on the bidentate phosphine ligand.