Volume 44, Issue 9

Ph—C(NSiMe 3 ) 2 AuCl 2 has been prepared by the reaction of N,N,N′-tris(trimethylsilyl)-benzamidine with AuCl 3 in CH 2 Cl 2 suspension, forming orange-red crystals, which were characterized by an X-ray structure determination. Space group P2 1 /n, Z = 4, 2358 observed independent reflexions, R = 0.028. Lattice dimensions (20°C): a = 695.9(3); b = 1576.1(3); c = 1830.9(3) pm; β = 94.27(3)°. The compound forms monomeric molecules, in which the gold atom is in a square planar arrangement of the two nitrogen atoms of the benzamidinato chelate (Au—N 201.6(7); 203.3(6) pm) and by two chlorine atoms (Au—Cl 227.9(3); 228.5(2) pm).

The title compound has been prepared by the reaction of N,N,N′-tris(trimethylsilyl)benzamidine with tantalum pentachloride in CH 2 Cl 2 suspension, forming amber-coloured, moisturesensitive crystals, which were characterized by an X-ray structure determination. Space group P 2 1 /n, Z = 2, 4895 observed independent reflexions, R = 0.059. Lattice dimensions (-65°C): a = 1165.2(6), b = 1335.4(6), c = 1629.0(7) pm, β = 93.23(4)°. The complex forms centrosymmetric molecules dimerized via chloro bridges TaCl 2 Ta with TaCl bond lengths of 247.2(2) and 277.1(2) pm, the longer one being in trans-position to the imido group, which can be formulated as [xxx] (bond lengths Ta=Ν = 183.5(8), C=N = 134(1) pm, bond angle TaNC = 162.7(7)°).

Colourless single crystals of [Eu(CH 3 COO)2(H 2 O)3]Cl are obtained at about 5°C from a solution of EuCl 3 · 6 H 2 O in a mixture of acetone, tetrahydrofurane and acetanhydride (1:1:2) to which a small amount of water had been added. [Eu(CH 3 COO)2(H 2 O)3]Cl crystallizes in the monoclinic system, space group P2 1 /n (No. 14), a = 786.19(5), b = 791.86(5), c = 1768.81(13) pm; β = 98.235(6)°, R = 0.025, R w = 0.021, Z = 4. Eu 3+ is in nine-coordinate surrounding of O 2- , three of which belong to water molecules and six to acetate anions (two bidentate and two monodentate). Cationic chains of the composition [Eu(CH 3 COO) 2 (H 2 O) 3 ] + are formed through further connection via acetate-oxygen atoms. These chains are stacked hexagonally parallel [100] and held together by “lonesome” Cl - anions. The chloride ions are surrounded by 4+1 aquo ligands.

The crystal structure of Na 3 Ga 8 Sn 3 (a = 1532.7(7), b = 890.7(6), c = 1224.9(8) pm; β = 129.6(2)°, space group C2/m) contains Ga 12 icosahedra and puckered layers of condensed sixmembered Ga/Sn rings, which are interconnected by additional Ga/Sn atoms to a three-dimen-sional framework. The Na content of the compound correlates with the number of electrons necessary for a stable electron configuration in the anionic partial structure.

Syntheses of neutral ' bu S 2 '-, 'S 4 '- and ' bu S 4 '- and of anionic .bu S 2 -complexes with various main group and transition metals are described. The complexes were prepared by reacting the neutral sulfur ligands or their alkali salts with the metal halide or alkoxide. The ligands coordinate to metal ions in normal as well as high oxidation states. No redox reactions occur in the latter case. The complexes are usually soluble in organic solvents and were characterized by elemental analysis and spectroscopic means.

A good entry to highly substituted phenylcarbyne complexes of tungsten containing tert-butyl-isonitrile ligands is provided via Br(CO) 2 (pic) 2 W≡CC 6 H 5 (1) (pic: γ-picoline). The first step includes the replacement of the picoline ligands in 1 by t-BuNC in refluxing CH 2 Cl 2 to give Br(CO) 2 (t-BuNC) 2 W≡CC 6 H 5 (2) in high yield. Complex 2 is then transformed with excess t-BuNC in toluene at 90°C to the carbonyl free carbyne complex trans-Br(t-BuNC) 4 W≡CC 6 H 5 (3). The monocarbonyl substituted analogue of 3, Br(CO)(t-BuNC) 3 W≡CC 6 H 5 (4), is observed by IR spectroscopy as an intermediate of this reaction. Its preparation is achieved by the CoCl 2 catalyzed decarbonylation of 2 in the presence of one equivalent of t-BuNC. trans-Br(t-BuNC) 4 W≡CC 6 H 5 (3) and the analogous iodocompound trans-I(t-BuNC) 4 W≡CC 6 H 5 (5) react with HX (X = Br, I) to give respectively, Br 2 (t-BuNC) 3 W[(t-Bu)HN—C≡C—C 6 H 5 ] (6) and I 2 (t-BuNC) 3 W[(t-Bu)HN—C≡C—C 6 H 5 ] (7) in high yield. Complexes 6 and 7 contain a 4e-donor acetylene ligand resulting from the proton induced coupling of one tert-butylisonitrile with the phenylcarbyne ligand at the tungsten center. The reaction of complex 4 with HBr leads also to the coupling product Br 2 (CO)(t-BuNC) 2 W[(t-Bu)HN—C≡C—C 6 H 5 ] (8), the carbonyl containing analogue of 6, in low yield. With one equivalent of t-BuNC and TlPF 6 compounds 6 and 7 are converted to the cationic complexes [Br(t-BuNC) 4 W[(t-Bu)HN—C≡C—C 6 H 5 ]] + PF 6 - (9) and [I(t-BuNC) 4 W[(t-Bu)HN—C≡C—C 6 H 5 ]] + PF 6 - (10) respectively. The analogous chloro compound [Cl(t-BuNC) 4 W[(t-Bu)HN—C≡C—C 6 H 5 ]] + PF 6 - (11) is obtained by halogen exchange from 10 and PPN+Cl - . The composition and structure of the new complexes 3, 4, and 6—11 have been determined by elemental analyses, IR, 1 H NMR, 13 C NMR and mass spectra.

Three new compounds, Ag 2 HgGeS 4 , Ag 2 HgSnS 4 , and Ag 2 HgSnSe 4 , crystallizing in the wurtzstannite type structure have been prepared by solid state reactions at 700°C and characterized by X-ray powder methods. A fourth compound of similar composition Ag 2 HgGeSe 4 , with an hitherto unknown structure crystallizes cubically with a = 10.796 A.

The title compounds were obtained by the reactions of PPh 4 Cl, HCl and ZnS or CdS in CH 2 Cl 2 . Their crystal structures were determined by X-ray diffraction. (PPh 4 ) 2 Zn 2 Cl 6 : a = 973.6(1). b = 982.6(2), c = 1296.7(3) pm, α = 107.93(2), β = 94.50(2), γ = 100.91(2)°, R = 0.036 for 2237 unique observed reflexions. (PPh 4 ) 2 Cd 2 Cl 6 : a = 977.1(2), b = 997.5(3). c = 1306.6(3) pm. α = 108.81(2), β = 94.18(2), γ = 100.24(2)°, R = 0.050 for 1921 reflexions. Both compounds are isotypic in the triclinic space group P1̄ and consist of PPh 4 + ions and dimeric, centrosymmetric M 2 Cl 6 - ions in which the tetrahedrally coordinated metal atoms are linked via chloro bridges.

Deprotonation of (R̲*,R̲*)-(±) )-[η5 -C 5 H 5 ){1,2-C 6 H 4 (PMePh) 2 }Fe(PH 2 Ph)]PF 6 with n-BuLi in tetrahydrofuran at 20°C, followed by treatment of the intermediate phenylphosphido-iron complex with [Cr(CO) 5 (NMe 3 )] produces a separable 3: 2 mixture of the diastereomers [(R̲*,R̲*),(R̲*)]- and [(R̲*,R̲*),(S̲*)]-(±)-[(η 5 -C 5 H 5 ){1,2-C 6 H 4 (PMePh) 2 }Fe-PH(Ph) → Cr(CO) 5 ]. The major component of the mixture crystallizes from dichloromethane-tetrahydrofuran in the atmosphere as the mixed solvate (R̲*,R̲*)-(±) )-[η5 -C 5 H 5 ){1,2-C 6 H 4 (PMePh) 2 }Fe(PH 2 Ph)]Fe-PH(Ph) → Cr(CO) 5 ]· 2 H 2 O-0.5 CH 2 Cl 2 · 0.5 C 4 H 8 O in the triclinic space group P1̅ with two formula units in the unit cell; the lattice constants are a = 10.933(2) Å, b = 13.161(4) Å, c = 15.249(3) Å, α = 76.83(1)°, β = 75.62(3)°, and γ = 79.31(1)°. In the structure, the pyramidal phenylphosphido group bridges the dissimilar metals via relatively long metal-phosphorus bonds, viz., Fe-P = 2.285(5) Å, Cr-P = 2.511(4) Å.

In the system LiI — ZnI 2 , the hitherto unknown peritectically melting Li 2 ZnI 4 has been established. It crystallizes in the olivine structure (a = 1480.3(9), b = 856.0(2), and c = 701.2(1) pm) and exhibits high ionic conductivity. Thermoanalytical and Raman spectroscopic data are included.

A series of aliphatic bis(acyl) selenides 1 were isolated from the reaction of acyl chlorides with sodium selenide and characterized.

Tetramethylarsonium-metaperiodate shows 127 I solid state NMR signals without any visible quadrupole splitting. Due to the very large nuclear quadrupole moments of the rhenium isotopes 185,187 Re, the analogous Re compound exhibits the expected second order quadrupole NMR effects. The measured 185,187 ReRe NMR powder spectra contain superimposed signals arising from two different types of ReO - 4 tetrahedra, indicating that part of the ReO 4 - anions deviate only slightly from tetrahedral symmetry, while the other part are nearly undistorted ReO 4 - anions. The temperature dependence of the solid state NMR spectra reveals phase transitions for both compounds, which are confirmed also by DSC analyses. Furtherm ore, the DSC analysis of the Re compound again proves the existence of the two different types of ReO 4 - tetrahedra in the lattice of the high temperature modification.

Based on the observation that the alkylidyne bridged cluster HFeCo 2 (CO) 9 (μ 3 -C—CH 3 ) spontaneously loses H 2 to form the vinylidene bridged cluster FeCo 2 (CO) 9 (μ 3 -C=CH 2 ), the interconversions between these types of ligands on mixed trinuclear clusters were investigated. It was found that in all cases clusters of the type HM 3 μ 3 -C—CH 2 R) could be transformed into clusters of the type M 3 (μ 3 -C=CHR); for M 3 = FeCo 2 , FeCoMo, RuCoMo, RuCoW, OsCoMo, OsCoW; for R = H and in one case CH 3 ; for dehydrogenation by thermolysis and in one case H + /H - elimination. Conversely, hydrogenation of the vinylidene bridged clusters to the alkylidyne bridged clusters was only possible for the FeCoMo, RuCoMo, and RuCoW systems, for the unsubstituted C=CH 2 ligand, and for elemental hydrogen as the reagent. Together with previous observations this leads to the conclusion that among the interconvertible alkyne, vinylidene, and alkylidyne ligands the vinylidene unit represents the most stable entity on trinuclear clusters.

Chelates of Ge(II) and Sn(II) Symmetrically and unsymmetrically substituted germane- and stannanediyls as well as chelated bis(amino)- or aminooxogermanium- and -tinmonohalides have been obtained from cyclic bis(amino)germane- and stannanediyls by treatment with tert-butylamine, tert-butanol and tert-butylmercaptane. The following compounds have been synthesized: GeX 2 (X = OtBu (5), StBu (6)), Sn(StBu), (9), GeXCl (X = N(H)tBu (21), OtBu (22)), SnXCl (X = N(H)tBu (23), OtBu (24), StBu (25), OMe (28)) and Sn(OtBu)Br (27). In the series of the chelates Me 2 Si(NtBu)(NHtBu)GeCl (13), Me 2 Si(NtBu)(OtBu)SnX (X = Cl (18), OMe (19)) and the bischelate [Me 2 Si(NtBu)(OtBu)] 2 Sn (20) have been prepared. When 18 is allowed to react with aluminiumtrimethyl Me 2 Si(NtBu)(OtBu)AlClMe is formed, a compound with a center of chirality at the aluminium atom. X-ray structure determinations have been performed on single crystals of 6, 8, 9, 13, 22 and 24. 6, 8, 22 and 24 form molecular dimers with c.n. of 3 at the Ge or Sn atoms, resp. While the tBu-S ligands are syn with respect to the central Ge 2 S 2 ring in 6 (symmetry approaching C 2v ), the tBu-O ligands are anti to the central Sn 2 O 2 ring in 8 (symmetry C i ). 9 forms a coordination polymer with all Sn atoms in a Ψ-trigonal-bipyramidal and all S atoms in a Ψ-tetrahedral environment. The germanium atom in 13 is coordinated by a chlorine, a λ 3 - and a λ 4 -nitrogen atom, the two nitrogen atoms being connected by as dimethylsilyl group. The hydrogen and chlorine atom of 13 are found at the same side of the four-membered chelate ring. The two unsymmetrically substituted, homologous compounds Ge(O/tBu)Cl (22) and Sn(OtBu)Cl (24) are found to form dimers via O→Ge resp. O→Sn bonds. While the chlorine atoms in 22 are syn with respect to the four-membered ring, they are anti in the case of molecule 24.

Derivatives of cyclopentadienyldifluorophosphine. e. g. CpPF 2 (1), Cp*PF 2 (Cp* = C 5 Me 5 ) (2),1-(indenyl)PF 2 (3), 9-(fluorenyl)PF 2 (4), 1-(ferrocenyl)PF 2 (5), 1,1′-(ferrocenyl)(PF 2 ) 2 (6) and also 1-N-phenyl-2-difluorophosphinopyrrole (7) were prepared using the reaction of the appropriate organolithium compound and PF 2 Cl. Their reactivity towards cis-dichloro-(η 4 -cyclooctadiene)-platinum(II) and tetracyanoethylene was investigated. The complexes poly-dichloro-bis-(cyclopentadienyldifluorophosphine)platinum(II) (8), cis-dichloro-bis-(pentamethylcyclopentadienyldifluorophosphine)platinum(II) (9), cis-dichloro-(3-indenyldifluorophosphine)(di(1-indenyl)-3-indenylphosphine)platinum(II) (10), cis-dichloro-bis-(9-fluorenyldifluorophosphine)platinum(II) (11) and cis-dichloro-bis-(1-N-phenyl-2-difluorophosphinopyrrole)platinum(II) (12) were prepared. 10 is the first mixed organodifluorophosphine-triarylphosphine-platinum(II)-complex. The structures of 9 and 10 were determined by X-ray crystal structure analyses. 9 crystallizes in the monoclinic space group, P2 1 /c with cell constants a = 835.3(2), b = 1479.0(3), c = 2071.7(4) pm, β = 99.67(2)° and Z = 4; R = 0.038 for 4760 unique observed reflections. The bonds to platinum are all short; Pt—P 220.3, 219.8(1), Pt—Cl 231.7, 231.9(2) pm. 10 crystallizes as a toluene hemisolvate in the monoclinic space group, P2 1 /n, with cell constants a = 1225.7(5), b = 995.0(3), c = 2886.3(10) pm, β = 90.83° and Z = 4; R = 0.074 for 2664 unique observed reflections. The precision was poor, but the unexpected presence of both 1- and 3-indenyl groups was unambiguously demonstrated.

The reaction of LFeCl 3 (L = N,N′,N″-trimethyl-1,4,7-triazacyclononane) with Na 2 SO 4 , Na 2 SO 3 /NaClO 4 , and Na 2 SeO 3 /NaClO 4 in aqueous solution affords the binuclear oxo bridged complexes [L 2 Fe 2 (μ-Ο)(μ-SΟ 4 ) 2 ]·3Η 2 Ο (1), [L 2 Fe 2 (μ-O)(μ-SO 3 ) 2 ]·5/3NaClO 4 ·(H 2 O) 3.67 (2), [L 2 Fe 2 (μ-O)(μ-SeO 3 ) 2 ](NaClO 4 ) 2.75 ·5H 2 O (3). The reaction of LFeCl 3 in dry methanol with Na 2 SO 4 yields yellow crystals of [L 2 Fe 2 (μ-SO 4 ) 3 ] · 2 H 2 O (4). The crystal structures of 1 and 2 have been determined by X-ray crystallography. Crystals of 1, 2, and 3 consist of neutral, binuclear μ-oxo bridged diiron(III) complexes which contain two additional O,O′-coordinated sulfato, sulfito, and selenito bridging ligands, respectively. The high spin ferric ions in 1, 2, and 3 are strongly intramolecularly antiferromagnetically spin exchange coupled with J values of —97(1), -104(2), and —104(2) cm -1 (H = —2JŜ,·Ŝ 2 , S 1 = S 2 = 5/2), respectively. 4 contains three μ-sulfato bridges between two Fe III ions. Only a very weak antiferromagnetic coupling has been detected (J = —5.5(5) cm -1 ). Complex 1 serves as a model compound for the diiron(III) complex of the sulfate treated, oxidized form of the biomolecule uteroferrin.

On UV irradiation, nootkatone (1) dimerizes in the crystalline state to give 2, 3 and 4. The dimerized products are formed through cycloadditions and radical reactions.

Regioselective reduction of a homologous series of O-n-hexyl to O-n-hexadecyl 2,3:5,6-bis-O-ethylboranediyl-β-D-mannofuranosides, la-k is achieved with ethyldiboranes(6) in the presence of 9-methanesulfonyloxy-9-borabicyclo[3.3.1] nonane [MSBBN]. After deboronation the mesogenic 1-O-n-alkyl-D-mannitols 2a-k are obtained, the liquid crystal ranges and solid state transitions of which are determined by D.S.C.

Two different molecules are observed in the asymmetric unit of the crystal structure of tert-butyloxycarbonyl-anthranilic-acid-glycin-methyl-ester (1). The whole conformational area (φ and ψ) of the amino acid part of 1 was investigated with the semi-empirical quantenmechanical method AM 1. The structures of 1 in the crystal are well described by the calculations. Rules are derived for the conformational space of peptides containing esters and anthranilic acids.

The 1 H NMR spectra of the following lichen substances have been correlated by NOE difference spectroscopy: atranorin, barbatic acid, diffractaic acid, nephroarctin, perlatolic acid, planaic acid methyl ester, pseudocyphellarin A, sphaerophorin (depsides), hypoprotocetraric acid, lobaric acid, pannarin, physodalic acid, psoromic acid, stictic acid (depsidones), picrolichenic acid (depsone), di-O-methyl-pannaric acid dimethylester, pannaric acid, porphyrilic acid, schizopeltic acid, strepsilin, and usnic acid (dibenzofurans).

Methyl 3-Methyl-4H-1,4-benzothiazines 2-Carboxylate A one pot synthesis of methyl 3-methyl-4H-1,4-benzothiazine 2-carboxylates is reported by the condensation and oxidative cyclization of substituted 2-aminobenzenethiols with methyl acetoacetate in DMSO.

Chiral esters of 2-[4-n-hexylphenyl]-5-[4-hydroxyphenyl]pyrimidine and 2-[4-n-hexyloxyphenyl]-5-[4-hydroxyphenyl]pyrimidine with four different α-fluorocarboxylic acids have been synthesized. The spontaneous polarization and the tilt angles in the smectic C* phase were measured as a function of temperature. All compounds exhibit wide range smectic C* phases, the highest values of the spontaneous polarization being about 400 nC/cm 2 . Additionally the spontaneous polarization in a higher ordered smectic phase was determined, the values ranging up to about 600 nC/cm 2 . The spontaneous polarization/tilt angle ratio strongly increases with decreasing temperature.

3-Alkoxy-2-methyl-1 H-isoindolium salts have been prepared either via regioselective O-alkylation of the corresponding 2-alkyl-isoindoline-1-ones or via regioselective N-alkylation of 3-alkoxy-1 H-isoindoles with trialkyloxonium tetrafluoroborates or with alkyl trifluoromethanesulfonates. Deprotonation of these stable precursors leads to the generation of reactive 1-alkoxy-2-alkyl-2H-isoindoles in solution. Reactions with CC-dienophiles (N-substituted maleic imides) give rise to the formation of 1 : 2-adducts. The two step reaction comprises Michael-addition and Diels-Alderaddition; the isolation of an initially formed 1:1-adduct is possible in the case of steric hindrance. Constitution and configuration of a representative 1 : 2-adduct has been established by X-ray crystal structure determination.

UV irradiation of trans-(CO) 3 Fe[P(OPh) 3 ] 2 yields an intermediate with loss of CO. This reacts with triorganostibanes SbR 3 to give products (CO) 2 Fe[(PhO) 3 P] 2 (SbR 3 ) with R = phenyl, 4-methylphenyl and cyclohexyl.

Using 293 K diffractometer intensity data, the structure of [H 3 N(CH 2 )3NH 3 ]SbCl 5 has been determined by single crystal X-ray technique and refined to a final R w of 0.026. The colorless crystals are monoclinic (space group P2 1 /c) with a = 10.1338(5), b = 11.4623(7), c = 11.3668(6) Å, β = 113.52(5)° and Ζ = 4. The structure contains ψ-octahedral SbCl 5 2- anions. A center of symmetry connects two anions forming a (Sb 2 Cl 10 ) 4- unit with rather long Sb—Cl distances for the bridging Cl-atoms (2.92 and 3.68 A, respectively).