Volume 46, Issue 6

Triphenylmethylphosphonium triiodide [P(C 6 H 5 ) 3 CH 3 ]I 3 has been prepared by the reaction of [P(C 6 H 5 ) 3 CH 3 ]I with iodine in ethanol. Deep violet crystals were obtained by recrystallization from dichloromethane. The crystal and molecular structure of the compound has been determined. The crystals are orthorhombic, space group Pbca, Z = 8, a = 1182.2(2), b = 1987.6(3), c = 1798.8(3) pm. Least squares refinement of the structure yielded R = 0.038 (R w = 0.030, R G = 0.030) for 2433 independent reflections. The triodide ion I 3 - is slightly asymmetrical and slightly bent. The distances are 293.7(1) pm (I(1)—I(2)) and 291.7(1) pm (I(2)—I(3)), the angle I(1)—I(2)—I(3) is 179.3(1)°. The structure contains layers perpendicular to the c axis, which follow each other with a period of c/2 and are built up by I 3 - anions and [P(C 6 H 5 ) 3 CH 3 ] + cations. They are stacked to give layers of cations and layers of anions perpendicular to the b axis. The shortest I ··· I distance between I 3 - ions in the anion layer occurs in the c direction. It amounts to 414 pm, thus indicating that there are only very weak I ··· I interactions between the I 3 - ions. Further I ··· I contacts in the layer lie between 510 and 746 pm.

In the reaction with benzophenone and phenylaldehyde lithiated aminofluorosilanes behave like iminosilanes. Four membered rings are formed in (2+2) cycloadditions. The oxaazasilacyclobutane ((CMe 3 ) 2 Si—NCMe 3 —C 6 H 5 CH—O—) was purified by destillation. Single crystals were obtained by recrystallization from hexane. The thermal cleavage of the (SiNCO)-rings leads to carboimines and cyclosiloxanes. The lithium derivate of di-tert-butylfluorosilyl-2.6-diisopropylphenylamine reacts with 2-methyl-propenal-2 in two competing ways. In a (2+4) cycloaddition an 1-oxa-3-aza-2-sila-5-cyclohexene is formed, and in a (2+2) cycloaddition 2-methyl-2-propenyl-N-(2.6-diisopropylphenyl)imine is generated via an (SiNCO)-ring intermediate.

The dichlorophosphido complexes (η 5 -C 5 Me 5 )(CO) 2 M–PCl 2 (2a: M = Fe; 2 c: M = Ru) react with two equivalents of Ph 2 C=NSiMe 3 to yield the first η 1 -2,4-diaza-3-phosphapenta-1,4-dien-3-yl complexes (4a,c). Intermediates (η 5 -C 5 Me 5 )(CO) 2 M–P(Cl)(N=CPh 2 ) (3a,c) are detected by 31 P{ 1 H} NMR spectroscopy, the preparation of pure 3a, however, failed. The products 4a, c have been characterized by elemental analysis as well as spectroscopic data (IR, 1 H, 13 C, 31 P NMR, MS). The molecular structure of 4a has been elucidated by single X-ray analysis.

The compounds [Cp′(CO) 2 Mn] 2 SeR + are isoelectronic analogues of the well known “inidene”-species [L n M]ER (E = P, As, Sb, Bi). While these latter “inidene” compounds exist in an open form with no metal-metal-interaction and the main group atom in a trigonal planar environment allowing for a three-center-4π-system MEM, their isoelectronic selenium analogues generally show equilibria between the “inidene”-type metal metal non bonded forms and their metal metal bond closed cyclic isomers. In a valence bond picture the four electrons, delocalized in the three-center-4π-system of the open isomers, are localized in the closed ones: two in the metal metal bond and two as a lone pair at a pyramidally coordinated selenium center. The corresponding equilibria are quantitatively analyzed for [Cp′(CO) 2 Mn] 2 SeR + (R = P CF 3 -C 6 H 4 (1), P CH 3 -C 6 H 4 ( P ToI) (2), °CH 3 —C 6 H 4 (°Tol) (3)) by UV/VIS spectroscopy of their solutions at different temperatures. The ring opening process which corresponds to the reversible opening of a metal metal bond is found to be entropically driven with reaction-entropies of around 25 [JΚ -1 mol -1 ]. Correspondingly, imposing steric hindrance on R, [Cp′(CO) 2 Mn] 2 SeMes + (4) yields a stable bond opened “inidene”-type compound. Reducing steric hindrance in [Cp′(CO) 2 Mn] 2 Se′Pr + (5) gives the bond closed form as the only detectable isomer.

The highly reactive arene iron complex [(η 4 -toluene)(η 6 -toluene)iron] allows the formation of C 4 -units from alkynes below room temperature. By this route butadiene-, cyclobutadiene-, and ferracyclopentadiene(arene)iron complexes are accessible. Synthesis, structure and the properties of one example each are reported. Ferracyclopentadienes are potential intermediates for the catalytic cyclotrimerization of alkynes in the coordination sphere of arene iron complexes.

Reactions of CuI with N-methylpyrazinium iodide, (pyr)I, N-methyl-4,4′-bipyridinium iodide, (bp4)I and N-methyl-2,2′-bipyridinium iodide, (bp2)I, in organic solvents led to three novel types of copper(I) complexes of stoichiometries (pyr)Cu 2 I 3 , (bp4)Cu 3 I 4 and (bp2)Cu 2 I 3 . In all of them the cations are n-σ-bonded to copper(I) through donation of their unshared electron pairs. (pyr)Cu 2 I 3 crystallizes with an ionic structure (trigonal, R 3 c, hexagonal axes a = 3053(2), c = 671.9(3) pm, Z = 18). Polymeric cations ∞ 1 [((pyr)CuI 3/3 ) 3 ] 3+ and anions ∞ 1 [CuI 4/2 ]-form parallel rod packings. The structure motif of the cations can be described as a columnar part of the β-CuI structure in which the copper and iodine atoms are also arranged to Cu 3 I 3 rings. The crystal structure of (bp4)Cu 3 I 4 (triclinic, P Ī, a = 938.8(2), b = 980.0(4), c = 1070.1(3) pm, α = 73.56(3), β = 75.79(2), γ = 89.50(3)°, Ζ = 2) is built up by uncharged chains ∞ 1 [(CuI 4/3 )(CuI 3/3 I 1/2 )((bp4)CuI 2/3 I 1/2 )]. The trinuclear units (bp4)Cu 3 I 4 are connected via common iodide edges. The copper halide connection motif of the polymeric compound has some features in common with the “stair” and “cube” structures of adducts of CuI with unidentate, neutral P-, As- or N-bases. The compound (bp 2)Cu 2 I 3 (monoclinic, P 2 1 /n, a = 1054.0(2), b = 1034.8(3), c = 1512.6(3) pm, β = 108.10(2)°, Ζ = 2) has a structure, in which two edge-sharing (CuI 4/2 )-tetrahedra and two approximately planar (CuI 2/2 (bp 2))-units form tetranuclear molecules (bp 2) 2 Cu 4 I 6 . These are linked to chains with a “stair” motif by intermolecular Cu ··· I contacts.

Reaction of (N-trimethylsilyl)-α-aminopicolin with the rhenium(V) oxohalogenide (η 5 -C 5 Me 5 )ReOCl 2 (Me = CH 3 ) exemplifies a simple, clean synthesis of imido-metallosiloxanes, compounds of the structure R 3 SiO—M=N—R′. The compound (η 5 -C 5 Me 5 )ReCl[OSi(CH 3 ) 3 ](NCH 2 -2-C 5 H 4 N) thus formed under HCl elimination has a square-pyramidal molecular structure (single crystal X-ray diffraction).

[(PhCH 2 ) 2 InN(H)t-Bu] 2 (3) and [PhCH 2 (Cl)InN(SiMe 3 )2] 2 (4) have been prepared by the reaction of (PhCH 2 ) 2 InCl with LiN(H)t-Bu and of PhCH 2 InCl 2 with NaN(SiMe 3 ) 2 , respectively. 3 could be isolated in two isomers, while 4 forms only one chloro-bridged isomer in solution and in the solid state. The possibility of a chloro-bridged alkyl(aryl)chloroindium amide is also realized in [Mes(Cl)InN(SiMe 3 ) 2 ] 2 (2), as shown by X-ray analysis. The reaction of a 1:1-mixture of i-Pr 2 InCl/i-PrInCl 2 with LiN(H)t-Bu leads to all three possible compounds: [i-Pr(Cl)InN(H)t-Bu] 2 (1), {i-Pr 2 In[N(H)t-Bu] 2 In(Cl)i-Pr} (5), and [i-Pr 2 InN(H)t-Bu] 2 (6). Two isomers of the new compound 5 are detectable in solution. The crystal structure has been determined for the less sterically hindered isomer 5a, which forms hydrogen-bridged (Cl-H-N-bridge) infinite chains along the c-axis.

6-(Furan-2-yl)-2,4-tetrakis(dimethylamino)-1-aza-2λ 5 , 4λ 5 -diphosphirine (2) and 6-(N-pyrrolidinyl)-2,4-tetrakis(dimethylamino)-1-aza-2λ 5 , 4 5 -diphosphirine (3) were prepared by reacting 1,1,3,3-tetrakis(dimethylamino)-1 λ 5 ,3 λ 5 -diphosphete with 2-cyanofuran, and N-cyanopyrrolidine, respectively. 2 and 3 are characterized by their physical properties, NMR, IR, and mass spectra. In 2 two 6 J(PH) long range coupling constants could be identified.

Zinc, cadmiun and mercury dihalide react with 4-acetylpyridinthiosemicarbazone (4-aptsc) to give complexes with 1:1 and 2:1 ligand/metal stoichiometric ratios. These metals are effective templates for the Schiff-base condensation of 4-acetylpyridine with semicarbazide to give the complexes [M(4-apsc)X 2 ] and [M(4-apsc) 2 X 2 ] where M = Zn, Cd or Hg and X = Cl, Br or I. These compounds were characterized by elemental analyses, conductivities measurements, IR and 13 C, 1 H NMR spectra. The zinc chloride and bromide complexes of benzalthiosemicarbazone (btsc) have been prepared and characterized by X-ray measurements. The compounds Zn(btsc) 2 Cl 2 and Cd(btsc) 2 Br 2 are isostructural and crystallize in the space group P2 1 /n. The crystal structure of the chlorine derivative has been resolved by single-crystal X-ray diffraction. The zinc centre is in a slightly distorted tetrahedral environment. There are intra and intermolecular hydrogen bonds.

In an attempt to provide phosphorus analogues of aminocarboxylic acids and their betaines, α, ω-bis(diphenylphosphino)alkanes (dppm, dppe, dppp, dppb) were converted into ω-phosphino-phosphoniocarboxylates and diphosphonio-biscarboxylates. While the reactions with haloacetic acids or haloacetates only lead to methylphosphonium derivatives owing to decarboxylation of the intermediates, β-chloropropionic acids converts Ph 2 P(CH 2 ) n PPh 2 compounds into the target products Ph 2 PCH 2 PPh 2 + (CH 2 ) 2 COOHCI - (1) and CH 2 [PPh 2 (CH 2 ) 2 COOH] 2 2Cl - (2), for n = 1. For n = 2, 3 and 4, only the analogues of 2 could be prepared (3-5). Treatment of 1 and 2 with sodium bicarbonate afforded the corresponding betaines Ph 2 PCH 2 PPh 2 + CH 2 CH 2 COO- (isolated as a dihydrate 6) and CH 2 [PPh 2 + CH 2 CH 2 COO - ] 2 (isolated as the tetrahydrate 7).

The o-phenylenediamine ligand tris[3-(2,3-diaminophenoxy)propyl]amine, TRIPACEN (4) and bis[3-(2,3-diaminophenoxy)propyl]amine, DIPACEN (8) are obtained by Williamson coupling of the potassium salt of 2,3-dinitrophenole (1) to tris(3-chlorpropyl)amine (2) or benzylbis(3-chlorpropyl)amine (5), respectively, followed by reduction of the nitro functions with Sn/HCl or Pd(OH) 2 /H 2 .

A heterogenized rhodium complex, prepared by sol-gel processing of Rh(CO)Cl[PPh 2 CH 2 CH 2 Si(OEt) 3 ] 2 and Si(OEt) 4 , is shown to catalyze the conversion of the silanes H 4-n SiPh„ (n = 1 - 3) or (HMe 2 Si) 2 O to (poly)siloxanes by air or water. Using THF as a solvent, the silanoles Ph 3 SiOH or Ph 2 Si(OH) 2 are obtained instead. The reaction of phenylacetic acid or acetic acid with HSiPh 3 to give silyl esters is catalyzed by the same compound.

The compounds Cs 6 M 2 X 4 (M = Al, Ga; X = P, As) were synthesized from stoichiometric mixtures of Cs, M and Cs 4 X 6 in sealed Nb ampoules at 950 K. They are isotypic and crystallize in the monoclinic space group P2 1 /c (No. 14) with Z = 4 formula units per unit cell. The anion partial structure is characterized by isolated [M 2 X 4 ] 6- units with relatively short distances for the terminal d(M–X) bonds corresponding to a Pauling Bond Order PBO = 1.5. The distances d(M–X) of the four-membered M 2 X 2 rings correspond to single bonds. The FIR spectra have been interpreted on the basis of the [M 2 X 4 ] 6- units with 2/m 2/m 2/m-D 2h , symmetry by considering a factor group splitting. The assignment of the observed frequencies is supported by a normal coordinate analysis.

Phase relationships and thermal decomposition of beryllium iodates and periodates were studied by X-ray and spectroscopic (IR, Raman) measurements. Be(IO 3 ) 2 · 4H 2 O, Be(IO 3 ) 2 , and Be(H 4 IO 6 ) 2 · 4H 2 O have been characterized. Be(H 4 IO 6 ) 2 · 4H 2 O (hitherto claimed in the literature to be a metaperiodate) dehydrates on heating with decomposition to form Be(IO 3 ) 2 . Anhydrous beryllium periodate was not obtained. On dehydration of Be(IO 3 ) 2 · 4H 2 O, anhydrous Be(IO 3 ) 2 is formed, which decomposes into BeO, I 2 , and O 2 on further heating.

The crystal structures of (TPP) 2 [B 6 Cl 6 ](CH 3 CN) 2 and (TPP) 2 [B 6 Br 6 ](CH 3 CN) 2 were determined from single crystal X-ray diffraction analyses at 147 K. They are triclinic, space group P1̅, and contain nearly regular octahedral anions with bond lengths d(B-B) 1.716, d(B-Cl) 1.818 for [B 6 Cl 6 ] 2- and d̅(B-B) 1.684, d̅(B-Br) 1.993 Å for [B 6 Br 6 ] 2- . Using these molecular data, normal coordinate analyses for the ten isotopomers [ 11 B n 10 B 6-n X 6 ] 2- , n = 0-6, X = Cl, Br, including the pairs of geometric isomers for n = 2, 3, 4 have been performed, based on a general valence force field. With a set of 8 force constants for Cs 2 [B 6 Br 6 ] (e.g. f d (BB) = 1.39, f d (BBr) = 3.18 mdyn/Å) and 10 for Cs 2 [B 6 Cl 16 ] (e. g. f d (BB) = 1.30, f d (BCl) = 4.01 mdyn/Å) the calculated frequencies are in good agreement with observed IR (10 K) and Raman bands (80 K) in natural abundance as well as for 11 B- and 10 B-enriched derivatives. For the series [B 6 X 6 ] 2- , X = Cl, Br, I the correlation of decreasing bond lengths d(B-B) and increasing force constants f d (BB) along with vibrational coupling between the B 6 cage and the substituent sphere is discussed.

3-Alkoxy-1 H-isoindoles bearing substituents at the five-membered ring have been synthesized starting with substituted isoindoline-1-ones via regiospecific O-alkylation with trialkyl oxonium tetrafluoroborates or alkyl trifluoromethanesulfonates and subsequent NH-deprotonation. The dependence of spectroscopic properties on the substituents has been investigated. The heterocyclic imidates exist exclusively in the benzenoid 1H-structure; the tautomeric o-quinonoid 2 H-form cannot be detected by spectroscopic means.

Korean Ginseng roots were extracted with methanol-water, water and liquid and supercritical ammonia. The yields of the extracts by different methods are reported. The extracts were analyzed by high-performance thin-layer chromatography. Retention value factors of ginsenosides are tabellized. The absolute yields have been measured in mg ginsenoside per g ginseng root for the used standard ginsenosides. Formally the ammonia extraction at 334 K and 26 bar is found to be favourable. The supercritical condition of 418 K and 130 bar leads to a decomposition of the ginsenosides. Possibilities of fractionation by different solvents or different temperatures are indicated, but attempts are still required to get fractions of several extraction agents.

The reaction of 5-amino-3,4-diphenylthieno[2,3-c]pyridazine-6-carboxamide 2 with formamide, acetic anhydride and carbon disulphide yielded pyrimido[4′,5′ :4,5]thieno[2,3-c]-pyridazin-4-one derivatives. Pyrimido[4,5-c]pyridazinethione and dithione derivatives were obtained by cyclocondensation of 3-amino-5,6-diphenylpyridazine-4-carbonitrile (8) with phenyl isothiocyanate and carbon disulphide, respectively. Tetrahydropyridazino[3,4-b]-quinoline (11) was prepared by reaction of 8 with cyclohexanone in presence of zinc chloride.