Volume 41, Issue 8

The crystal structure of [Mg(H 2 O) 6 ](N 3 ) 2 was determined by single crystal X-ray diffraction (421 independent observed MoKα-counter reflections. R = 0.037). The crystals are orthorhombic, space group Fmmm, Z = 4, a = 644.3(1), b = 1134.4(1), c = 1333.5(3) pm. The magnesium atoms are octahedrally coordinated to six oxygen atom s of water molecules, the azide groups are not coordinated to metal atoms, N -N = 117.0(2) pm.

[(nC 3 ,H 7 ) 4 N] + [P 4 S 4 N] − 1 has been synthesized from P 4 S 10 and [(nC 3 H 7 ) 4 N] + [S 2 P(N 3 ) 2 ] − . 1 crystallizes in the space group P2 1 /c with a = 936.9(2), b = 1731.1(3), c = 1694.6(3) pm , β = 93.41(2)° and Z = 4. The [P 4 S9N]~ anion has an adamantane-like structure, with bridging rather than terminal nitrogen.

The new compound Tl 3 AgTe 2 was prepared by the reaction of Tl 5 Te 3 , Ag and Te at 550 °C, followed by slow cooling of the melt. It forms black crystals of metallic lustre which decompose by the influence of humidity. Tl 3 AgTe 2 is monoclinic, space group P2 1 /c, with a = 11.020(5), b = 7.427(2), c = 9.888(3) Å , β = 116.62(4)°, Z = 4. The crystal structure was determined from four-circle diffractometer data and refined to a conventional R of 0.083 for 1015 observed reflections. Tl 3 AgTe 2 crystallizes with a new structure type, characterized by infinite layers, 2 ∞ [AgTe 2 ], running along (100), which are separated from each other by thallium atoms. The layers are built up by pairs of edge sharing AgTe 4 -tetrahedra linked together by common Te atoms according to 2 ∞ [Ag (Te)Te 3/3 ]. The crystal structure is based on an arrangement of distorted c.p. tellurium layers, stacked along [010] (stacking sequence h 2 ). All octahedral voids are occupied by Tl-atoms, Ag-and Tl-atoms are regularly distributed over the tetrahedral sites.

Crystal Structure, Equiatomic Ternary Rare Earth Metal Cobalt Carbides The crystal structure of the new compound YCoC was determined from X-ray powder data. It is tetragonal, space group P4 2 /mmc, with a = 0.36500(4) nm, c = 0.68636(9) nm and Z = 2 formula units per cell. The residual for a refinement of Debye-Scherrer data is R = 0.048 for 22 structure factors and 3 variable parameters. The structure is of a new type with no variable positional parameter. The arrangement of the metal atoms corresponds to that of the CsCl structure. The tetragonal superstructure with a doubled c axis arises through the ordered insertion of carbon atoms on octahedral sites formed by four Y and two Co atoms. The hydrolysis of YCoC in hydrochloric acid yields mainly methane, propane, and ethane. The compounds LnCoC (Ln = Gd -Tm, Lu) are isotypic with YCoC.

Yellow crystals of cis-[SnCl 4 (S 8 O) 2 ] containing the homocyclic sulfur oxide S 8 O have been prepared from the com ponents in carbon disulfide at -35 °C. An X-ray structural analysis carried out at -105 °C showed the com pound to be monoclinic, space group P2 1 /n with Z = 4 in a unit cell of dimensions a = 821.2(2) pm, b = 1331.9(4) pm , c = 2071.7(6) pm and β = 91.82(2)°. The structure was refined to a final agreement factor R = 0.038 for 2022 reflections. The tin atom is surrounded by a distorted octahedron of two oxygen atoms in cw-positions and four chlorine atoms in accordance with other oxygen-bonded complexes of SnCl 4 . The molecular symmetry is approximately C 2 , and the SS bond lengths in the ligands vary between 201 and 218 pm. Vibrational spectra of [SnCl 4 (S 8 O) 2 ] are reported. The title compound is the second example containing S 8 O as a ligand.

The homocyclic S 11 and S 13 molecules have been synthesized from titanocenepentasulfide and S 6 Cl 2 or S 8 Cl 2 , respectively, and obtained as yellow crystals which are metastable for several days at 20 °C. X-Ray structural analyses of single crystals at -105± 5 °C exhibited molecules of approximately C 2 symmetry with bond distances (d), bond angles (a) and torsional angles (r) in the following ranges: S 11 : d = 203.2 -211.0 pm, α = 103.3-108.6°, τ = 69.3 - 140.5°; S 13 : d = 197.8 - 211.3 pm, α = 102.8-111.1°, τ = 29.5 - 116.3°. Infrared and Raman spectra of S 11 and S 13 are reported. In addition, the synthesis of S 6 Cl 2 and S 8 Cl 2 from S 6 or S 8 , respectively, and chlorine is described.

Bis(/75-cyclopentadienyl)-chloro-selenophenolatotitanium (IV), Bis(?75-cyclopentadienyl)-chloro-selenophenolatozirconium (IV), Bis(//5-cyclopentadienyl)-chloro-selenophenolatohafnium (IV), Bis(^5-cyclopentadienyl)-chloro-selenophenolatotungsten(IV), Mass Spectra The metallocene chloro selenophenolates C p;M Cl(SeChH 5) (Cp = ^5-C5H 5; M = Ti, Z r, Hf, W) were prepared by reaction of Cp2MCl2 with equivalent am ounts of LiSeC6H 5, obtained from phenylselenol and «-butyllithium, and were characterized by 'H NM R, IR and MS data. The fragmentation behaviour of the Ti and W derivatives is elucidated by observing m etastable transi­ tions in the mass spectra.

Perfluoro-3-phosphapent-2-ene F 5 C 2 P =C (F )CF 3 (1) has been prepared for the first time by thermal elimination of trimethyltin fluoride Me 3 SnF from trim ethylstannyl-bis(pentafluoroethyl)- phosphane Me 3 SnP(C 2 F 5 ) 2 at 300 °C/10 −3 Torr. 1 is found to be less stable than F 3 CP = CF 2 in dilute solution at room temperature, forming several 1,3-diphosphabutane dimers. Reactivity studies accomplished till now include (i) the dienophilicity of 1 in [2+4] cycloaddition reactions with butadiene, 2,3-dim ethylbutadiene, cyclopentadiene, 1,3-cyclohexadiene, 2-methylbutadiene, and 2-methylfuran leading by a concerted mechanism to the Diels-Alder-adducts 2-7 in about 80% yield, (ii) the addition of proton acidic compounds HX (X = OMe, Br, NMe 2 , NEt 2 ) to the PC double bond affording chiral phosphanes of the type F 5 C 2 P(X)CF(CF 3 )H [X = OMe (8). Br (9). NMe 2 (10). NEt 2 (11)]. thus proving a stronger polarity δ+ P = δ− C for 1 than for F 3 CP = CF 2 . New compounds have been characterized by NMR and MS measurements.

The reaction of CpMn(CO) 2 THF or Cr(CO) 5 THF with alkylchalcogenides ER 2 (E = S, Se, Te; R = Me or R 2 = (CH 2 ) 3 , (CH 2 ) 4 ) in the molar ratio of 2:1 gives alkylchalcogenide-bridged dinuclear complexes [CpMn(CO) 2 ] 2 ER 2 and [Cr(CO) 5 ] 2 ER 2 . The heteronuclear complex Cp(CO) 2 Mn - (μ-SMe 2 ) -Cr(CO) 5 can be synthesized by reacting CpMn(CO) 2 SMe 2 with Cr(CO) 5 THF. X-ray structure analysis of the compound [CpMn(CO) 2 ] 2 S(CH 2 ) 3 demonstrates the bridging character of the alkylchalcogenides.

Crystallographic data for mixed phosphate/vanadate fluoroapatites of the type M 10 (PO 4 ) 6−x (VO 4 ) x F 2 (with M = Ca, Sr, Ba and x = 1-3) have been obtained from X-ray powder data. The only structural effect observed is a continuous increase of unit cell dimensions with increased vanadate incorporation. The IR and Raman spectra show that the VO 4 3− incorporation has a negligible effect on the strength of the P - O bonds, although a small bond weakening for both tetrahedral oxoanions is observed as the unit cell volume increases. The results are comparable to those reported earlier for similar mixed hydroxyapatites and suggest that the fluoroapatite lattice can be considered as a good “model” for the vertebrate hard tissues.

, 41 [1] Synthese, Struktur und Eigenschaften neuer silyl-, germyl-und stannylsubstituierter Heptaphosphane(3) P7(MPh3)3 mit M = Si, Ge, Sn Chemistry and Structural Chemistry of Phosphides and Polyphosphides, 41 [1] Synthesis, Structure and Properties of New Silyl, Germyl and Stannyl Substituted Heptaphosphanes(3) P7(MPh3)3 with M = Si, Ge, Sn Silyl-, Germyl-and Stannyl-substituted H eptaphosphanes(3), 3,5,7-T riphenylm etalla[2.2.1.02'6]hepta-phosphanes, Structures, Raman Spectra, 31P NM R Spectra New derivatives P7(M Ph3) 3 (M = Si, G e, Sn) o f the heptaphosphanortricyclen cage were synthesized by reactions o f P7(SiM e,) 3 with com pounds CIMPh,. The driving force o f the reaction is the lower solubility o f the P7(M P h,) 3 com pounds. W hereas crystals of P7(SiM e3) 3 are enan-tiom orphs, the new com pounds P7(M Ph3) 3 crystallize as racemates. With decreasing M size, the nortricyclen cage P7 is slightly twisted about the 3-fold axis. The main P -P bond lengths in the cage follow the relation A (basal) — 221.8 pm > B (basal-equatorial) = 219.0 pm > C (equato-rial-apical) = 218.5 pm. The m ean bond lengths P —Si = 228.6 and P —Ge = 234.9 and P —Sn = 253.5 pm are slightly larger than the standard single bond distances. The IR absorptions show only very small M -dependent variations in the characteristic internal cage vibrations. Similar effects are recognized in the 3,P NM R chem ical shifts.

Bis(tetrapropylammonium)heptasulfide results from the reaction of [(C 3 H 7 ) 4 N]Br and Na 2 S 5 (molar ratio 4:1 to 2:1) in aqueous solution. The dark orange compound crystallizes in the space group P2 1 /c, the lattice constants are (at -70 °C): a = 9.466(4) Å , b = 11.013(3) Å, c = 16.845(7) Å , β = 105.6(1)°. It contains unbranched chainlike S 7 2− anions of all-trans-conformation.

The dicarbene complexes, MnBr(CO) 3 [xxx] (1) and [xxx] (2), are synthesized from metal carbonyl precursors and CNCH 2 CH 2 OH . Factors influencing this 2-hydroxyalkyl isocyanide → N ,O-carbene isomerization are discussed. The crystal and molecular structure of 2 shows a distorted trigonal geometry about the central Ni atom. Extensive hydrogen bonding ((N )H ··· F 2.09, 2.38 Å ) occurs between cations and anions giving rise to infinite chains. Other pertinent bonding parameters are Ni-C (carbene) 1.860(4), 1.864(4) Å; C(carbene) [xxx] N 1.309(6), 1.304(6) Å , and C - Ni - C 97.7(2)°.

Several 3 .11-disubstituted dispiro[5.1.5.1]tetradecane-7,14-dions were prepared and the cis/trans-isomers were separated. The trans -stereoisomers were converted into the gem-dihalide ketones and mono- and dithioketones. The phase transfer temperatures were determined. Liquid crystal phases were observed.

Hydroxyl radicals from the radiolysis of N 2 O/O 2 (4:1)-saturated aqueous solutions of acetone (10 −3 mol dm −3 ) react with the solute by H-abstraction thereby forming acetonyl radicals. As shown by pulse radiolysis, the acetonyl radicals rapidly add oxygen (k = 3 x 10 9 dm 3 mol −1 s −1 ) thereby forming acetonylperoxyl radicals which decay by second-order kinetics (2 k = 8 x 10 8 dm 3 mol −1 s −1 ). Under steady-state radiolysis conditions (0.24 Gy s −1 ) the products (G values in parentheses) are methylglyoxal (2.5), hydroxyacetone (0.5), form aldehyde (1 .6), acids (1 .7), carbon dioxide (0 .5), organic (hydro)peroxides (0.4), hydrogen peroxide (2 .2), and G (oxygen uptake) has been determined at 5.2. In the decay of the acetonylperoxyl radicals the major process (slightly less than one half) leads in a concerted reaction to two molecules of methyl­ glyoxal and one molecule of hydrogen peroxide. The Russell mechanism which yields one molecule of methylglyoxal, hydroxyacetone and oxygen contributes about one fifth as does the breakdown into two molecules of form aldehyde, one molecule of oxygen and two acetyl radicals. Carbon dioxide, formaldehyde and acetic acid are among the products which result from the acetylperoxyl radicals formed upon oxygen addition to the acetyl radicals. A bout one tenth of the organic peroxyl radicals is converted into hydroperoxides by O 2 ⨪ produced as a byproduct in the water radiolysis.

The hydrogen isocyanide complexes [M (CO) 5 CNH] (M = Cr, Mo, W) have been treated with the aziridines R [xxx] H 2 (R = H, R’ = H, Me, Et; R = Me, R’ = H) to give imidazolidin-2-ylidene complexes. The same type of ligand forms on addition of aziridine to the electrophilic isocyanide group in [FpCNPh] + in the presence of Br − , IR, 1 H NMR, 13 C NMR and mass spectra of the new compounds are reported.

The novel cluster compounds Ru 55 [P (tert -Bu)3] 12 Cl 20 , Rh 55 (PPh 3 ) 12 Cl 6 and Pt 55 [As(tert -Bu) 3 ] 12 Cl 20 have been prepared by the reaction of (RuCl 3 /P (tert-Bu) 3 ), (Ph 3 P) 3 RhCl and trans-[As(tert -Bu) 3 ] 2 PtCl 2 , respectively, with B 2 H 6 in THF or benzene. Diborane reduces the metal salts and serves to capture excess of phosphine or arsine ligands. Molecular weight determinations prove the cluster size. High resolution transmission electron microscopic investigations on the Pt 55 cluster show the expected full-shell cuboctahedron with 55 closest-packed platinum atoms. 31 P NMR spectra prove the ligands to be very mobile.

A new spermidine alkaloid, capparisine (1) has been isolated from the alcoholic extract of the root bark of Capparis decidua, and its structure was elucidated by spectral studies.

The mesophases of eleven homologous hexaesters ( 1b -1) of the naturally occurring scylloinositol (1a ) representing the first series of alicyclic saturated discogens are studied by calorimetry and optical microscopy. The three derivatives 1 b -d of this hexahydroxy cyclohexane with each six acetyl, propionyl or butyroyl side chains, respectively, exhibit a very organized discophase D 1 . The hexa-0-acetyl-scyllo-inositol (1b , range of mesophase: Δt = 4.8 °C!) is the discogen having the shortest identical ester groups as lateral functions so far reported for discotic liquid crystals. The pentanoyloxy com pound (1e) exhibits a monotopic D 0 mesophase and an enantiotropic optically isotropic and, probably, cubic mesophase D 0 different from the smectic D mesophase. Versus increasing temperature the phase sequences are D 1 → D E and D 1 → D 0 . Examples of mutual orientation of D 1 and D E discophases and binary mixtures exhibiting stable D E discophase at room temperature are also reported. The mesophases of seven more compounds (1f-1) of the homologous series having lateral functions larger than pentanoyloxy are identified by total miscibility as discophase D E . Their stable temperature ranges are very wide e.g. hexa-0-heptanoyl-scyllo- inositol (1g , Δt = 132 °C) which are exceeded only by those discogens having much larger “cores” (up to now of aromatic character only).

Keywords When in the conventional triphenylmethylium dye systems of the crystal violet and malachit green type, 6 and 7, the N̈ -donor and C ⊕ -acceptor centers are interchanged , the “Inverse Triphenylmethylium Dye Types” 4 and 5 are obtained , showing very similar colors. The stable models with R = phenyl (8-10) and R = p-tolyl (11-13) were investigated in more detail. The visual observations were supported by the VIS spectra which show ed nearly the same longest wavelength absorption maxim a for corresponding pairs of inverse and conventional dye representatives. The experimental results can be interpreted with a simple HMO -model according to which the longest wavelength absorptions correspond here to transitions of equal energy from weakly bonding to nonbonding and from nonbonding to weakly antibonding molecular orbitals, respectively. On the same basis numerous isoelectronic variants of that dye type can be envisaged. In the N M R -spectra of the new dyes, characteristically increasing deshieldings of nearly all positions are observed in going from the mono- (10 + , 13 + ) through the di- (9 ++ , 12 ++ ) to the trications (8 +++ , 11 +++ ).