Title Com Research Articles

Molecular Structure and Vibrational Spectra of Alpha-benzoinoxime by Density Functional Method

In the present study, an exhaustive conformational search of the Alphabenzoinoxime has been performed. The FTIR spectrum of this compound was recorded in the region 4000-400 cm -1 . The FT� Raman spectrum was also recorded in the region 3500-50 cm -1 . Vibrational frequences of the title com� pound were calculated by B3LYP method using 6�311++G(d, p) basis set. The calculated vibrational fre� quences were analysed and compared with experimental results.

Crystal structure of 1,3-diisopropyl-4,5-dimethylimidazolium oxalic acid monomethyl ester, C14H24N2O4

Abstract C14H24N2O4, monoclinic, P21/n (no. 14), a = 8.1862(8) Å, b = 10.313(1) Å, c = 18.534(2) Å, β = 101.018(8)°, V = 1535.8 Å3, Z = 4, Rgt(F) = 0.0567, wRref(F2) = 0.1064, T = 173 K.

Design, Synthesis and Antitumor Activity of Dimeric Bile Acid-Amino Acid Conjugates

Nine dimeric bile acid-amino acid conjugates as the mimic of cycle peptide and they have been synthesized in good yield and their structures were well confirmed by 1 H NMR, 13 C NMR and mass spectra. The ESI-MS n technique was used to probe the conformation of these molecules. The preliminary bioactivity tests showed that some of the title com- pounds could inhibit the growth of human breast cancer cell MCF-7. The antitumor activity probably derived from the unique sandwich-type amphiphilic conformation. Keyword: Bile acid, amphiphile, electrospray mass spectrometry, cytotoxic activity.

Chiral 1,2-Amino Alcohols and 1,2-Diamines Derived from Cyclohexene Oxide: Recent Applications in Asymmetric Synthesis

This Account describes convenient procedures for the preparation of several enantiopure b-amino alcohols and b-di- amines, which have proved to be efficient ligands in relevant ste- reoselective reactions such as alkylation of enolates and hydrogenation of carbonyl compounds. Furthermore, the title com- pounds are useful precursors of various chiral oxazolidinones, ox- azinones, phosphonamides, etc., which allow the enantioselective formation of a wide variety of chiral derivatives, including alcohols, aldol condensation products, aminophosphonic acids, sulfoxides, and others, as well as the development of derivatizing reagents for the determination of enantiomeric purity in chiral alcohols and chiral amines.

Novel Short‐Step Synthesis of Functionalized γ‐Phenyl‐β‐hydroxybutenoates and Their Cyclization to 4‐Hydroxycoumarins via the N‐Hydroxybenzotriazole Methodology.

A novel method for the synthesis of functionalized 3- substituted 4-hydroxycoumarins is reported. C-Acylation com- pounds were derived from the reaction of the N-hydroxybenzotri- azole ester of the functionalized acetyl salicylic acids and a variety of active methylene compounds and cyclized to the title com- pounds. The synthesis is simple and the compounds are produced in yields varying from 39 to 80%. The structure of the newly prepared C-acylation compounds was thoroughly studied through NMR spectroscopy for the first time in the literature.

Die Kristallstrukturen von PHF4, PH2F3 und PHF2. Moden molekularer Packung bei tiefer Temperatur [1] / The Crystal Structures of PHF4, PH2F3 and PHF2. Molecular Packing Modes at Low Temperature

The title com pounds have been prepared in partly new ways and their crystal structures determined. The molecular geometries are found similar to those of the respective gas phases and those obtained by ab initio calculations. On the intermolecular level, there are indications of weak hydrogen bonds P-H···F in all three structures and of likewise weak fluorine bridges P-F···P in PH2F3 and PHF2 with the latter further featuring a close P···P contact.

Die Kristallstruktur von [(THF)2Li(μ2-Cl)2TiCl2(THF)2] / Crystal Structure of [(THF)2Li(μ2-Cl)2TiCl2(THF)2

Abstract The crystal structure of the title com pound has been determined by X-ray methods. Space group C2/c, Z = 4, lattice dimensions at -80 °C: a = 1343.8(2), b = 1031.6(1), c = 1669.4(1) pm, β = 96.47(1)°. The compound forms an ion pair in which the lithium atom is coordinated in a distorted tetrahedral geometry by two THF molecules and by two chlorine atoms. The halide atoms have a μ2-bridging function, coordinating the lithium and the titanium center. The titanium atom possesses a distorted octahedral environment with two THF ligands in trans-position.

Dielectric Relaxation in Nematic and Isotropic Phases of 4-(trans-4'-n-Propylcyclohexyl) isothiocyanatobenzene

Abstract The results o f a dielectric relaxation study (in the frequency region from about 1 kHz to 1 GHz) of the liquid crystalline title com pound (C3H7-Cyhx-Ph-NCS , 3-CHBT) in the isotropic and the nematic phase (measurements with electric field parallel to alignment) are presented. The spectra of both phases can be described by two relaxation processes of Debye-type, possibly related to rotation around the long and short molecular axes.

Die Kristallstruktur von TIZnPO4 und TIZnAsO4 / The Crystal Structure of TIZnPO4 and TIZnAsO4

Single crystals of the title com pounds were obtained by high pressure synthesis in a modified Belt type apparatus. The compounds crystallize in the monoclinic system (space group P21) with a = 8.732(2), b = 5.468(1), c = 8.841(2) Å, β = 90.61(2)° for TlZnPO4 and a = 8.921(3), b = 5.631(1), c = 8.958(3) Å, β = 91.03(2)° for TlZnAsO4, Z = 4. The structures were refined from diffractom eter data to R = 0.072, Rw = 0.050 for 3700 (TlZnPO4) and to R = 0.093, Rw = 0.067 for 3943 (TlZnAsO4) independent absorption corrected reflections. The compounds are isotypic and belong to the “stuffed derivatives" of the Icmm structure type with a (ZnXO4)- network of alternating corner linked ZnO4 and XO4 tetrahedra (X = P, As) forming channels of six-membered rings in the direction of the a axis. These cavities contain two crystallographically independent Tl cations in an irregular coordination by eight nearest oxygen atoms

Die Kristallstruktur von Tetraphenylarsoniumchlorid-dihydrat / The Crystal Structure of Tetraphenylarsoniumchloride Dihydrate

Crystals of the title com pound were obtained after reaction of tetraethylam monium-hydroxooxalato-titanate(IV ) with tetraphenylarsonium - chloride in water. The crystals are orthorhombic, space group P nma with a = 16.288(2) Å, b - 10.708(3) Å, c = 12.787(3) Å, Z = 4 ,V = 2230.2 Å3.

Inequivalent Reorientation of the Trichloromethyl Groups in 1,4-Bis(TrichloromethyI) Benzene as Studied by Pulsed 35Cl NQR

Abstract The temperature dependence of T1 of 35Cl NQR of the title com pound evidenced that the three crystallographically inequivalent CCl3 groups have different potential barriers against reorientation (about 30, 36, and 42 kJ/mol). An intramolecular interaction between π-electrons on the benzene ring and the C -Cl bond is proposed to interpret the characteristic frequency splitting common to the 35Cl NQR spectrum of each of the three inequivalent CCl3 groups. The magnitude of T2 of each Cl atom is interpreted by intra-and intermolecular H ··· Cl interactions. It was found that only part of the temperature dependence of the NQR frequency can be interpreted by reorientation.

Structure of methyl 2-(2,5-dihydro-2-oxo-3-phenyl-5-furyl)lactate

C!4Hi405, M r = 262.26, monoclinic, P211n, a = 11.319 (3), b = 6.5115 (15), c= 18.105 (5) A,/3 = 105.660 (20) °, V = 1284.8 (6) A3, Z = 4, Dx = 1.356 g cm -3, A(Cu Kay) = 1.54056 A, /z = 8.26 cm- 1, F(000) = 553.89, T = 295 K, R = 0.036, wR = 0.033 for 1692 reflections with I > 2.50-(/). The structure determination established the identity of the product of a Co2(CO)8-catalyzed carbonylation reaction with an epoxy alcohol. Experimental. A colourless crystal of the title com- pound (1) was grown from THF solution. Cell parameters from 20 reflections in the 20 range 85-90 °. Data were collected on a Picker diffractom- eter using profile analysis (Grant & Gabe, 1978). Three standards measured every 100 reflections were used for scaling and had an overall drop in intensity of 6%. Averaging of symmetry-equivalent reflections gave a merging R value of 3.3%. Parameters related to crystal data and intensity collection are given in Table 1. The structure was solved by direct methods and refined by cycles of least-squares calculations. H atoms were located in a difference map and refined isotropically. Final atomic parameters are listed in Table 2. All non-H atoms were refined anisotrop- ically. All computing was performed with the NRCVAX system of structure-solving programs (Gabe, Le Page, Charland, Lee & White, 1989). Scattering factors from International Tables for X-ray Crystallography (1974, Vol. IV).* o o OH 0

Polysulfonylamine, XXI [1]. Bis(dimesylamino)sulfan und Bis(dimesylamino)disulfan: Darstellung, Eigenschaften und Festkörperstrukturen

High yield syntheses of the new diaminosulfanes (CH3SO2)2NSN (SO2CH3)2 (1) and (CH3SO2 )2 NSSN (SO2CH3)2 (2) are reported. 1 is obtained by the action of elemental sulfur on (CH3S O2)2NCl and by metathesis of (CH3SO2)2N Ag with SCl2, 2 by the analogous metathesis with S2Cl2. 2 is converted to 1 by partial desulfurization with (C6H5)3 P. 1 and 2 are active transfer reagents of the S2⊕ or S5⊕ group, respectively. Thus, the reaction o f 1 or 2 with n -butanol gives the alkoxysulfanes C4H9OSnOC4H9 (n = 1, 2), and their reaction with [(CH3)3Si]2NH leads to the silylated diaminosulfanes [(CH3)3Si]2NSnN[Si(CH3)3]2 (n = 1, 2). The crystal structures of the title com pounds were determined at - 9 5 °C. The most important features of the structure of 1 are the near planarity of the three bonds around the nitrogen atoms (sum of bond angles 356.9 ), the distances N - SII 169.7 and N -SVI 171.5 pm , and the N - SII -N bond angle o f 105.3° (mean values for two independent molecules). In 2, both nitrogen atoms have a planar geometry (sum of bond angles 360.0°; distance from the plane of their bonded atoms ≤ 2 pm). All N - S bond lengths are approximately equal (mean values: N - SII 170.4, N - SVI 170.7 pm). The S - S bond length is 202.1 pm. The torsion angle N - S - S - N of -8 5 ° lies in the usual range for disulfides X - S - S - Y . For comparison, the known structure of CH3 - N (SO2CH3)2 was redetermined at - 9 5 °C.

Tris(benzoyl-thiobenzoyl-methanato-O,S)indium, a Conformer of a Facial Isomer

Abstract A second modification o f the title com pound has been isolated and characterized by an X-ray structure analysis. It crystallizes in the monoclinic space group P21/c. The indium atom is hexacoordinated and surrounded by three sulfur and three oxygen atoms in a facial arrangement as has been found for a previously known isomer. However, the phenyl groups adopt a different orientation, hence it is a rotamer.

Synthese und Kristallstruktur des Amidinatokomplexes Ph-C(NSiMe3)2TeCl3 / Synthesis and Crystal Structure of the Amidinato Complex Ph —C(NSiMe3)2TeCl3

Abstract The title com pound has been prepared by the reaction o f N ,N ,N '-tris(trimethylsilyl)-benzamidine with tellurium tetrachloride in CH2Cl2 solution. The complex was characterized by an X-ray structure determination. Crystal data: space group P 1̄ , Z = 2, (2428 observed independent reflexions, R = 0.031). Lattice dimensions (19 °C): a = 946.7(1), b = 1031.5(1), c = 1337.1(1) pm; α = 67.411(8)°, β = 68.508(9)°, γ = 67.195(8)°. Ph-C(NSiMe3)2TeCl3 forms monomeric molecules, in which the tellurium atom is ϕ-octahedrally surrounded by three chlorine atoms and by the two nitrogen atoms of the amidinato chelate (bond lengths Te -N = 209.6 and 219.2 pm). The lone pair at the tellurium (IV) center and the small bite angle of the ligand cause a strong distortion of the octahedral geometry.

Novel manganese(III) oxidation chemistry: X-ray crystal structure of 5,7,8-trimethoxy-1-(2,4,5-trimethoxyphenyl)-1,2-dihydronaphthalene

C22H2606, Mr= 386.4, monoclinic, P2~/c, a= 13.021 (4), b= 11.044 (2), c= 14.036 (9)A, fl = 102.53 (4) °, V= 1970.4 A 3, z = 4, D x = 1.30g cm -3, 2(Mo Ka) = 0.71073 A, #= 0.56 cm -~, F(G00) = 824, T= 293 K, final R = 0.054 for 1576 observed (F o > 5a(Fo)) reflections. There is no crys- taUographically imposed symmetry. The title com- pound is prepared by manganese(liD acetate oxidative dimerization of two molecules of 2,4,5-trimethoxy- styrene. Introduction. During the course of our investigations on manganese(III) acetate mediated ring annulative approaches to the antineoplastic podophyUotoxins (Peterson, Do, Winter & Surjasasmita, 1988; Peterson, Do & Surjasasmita, 1988), an unusual oxidation product was obtained when the alkene component of the annulation reaction was 2,4,5-trimethoxystyrene. The single electron transfer oxidation (SETO) of electron-rich alkenes by manganese(III) recently had been reported by one of us to provide 1,2-diacetates, 1,2-hydroxyacetates, and their oxidation products (Fristad, Peterson, Ernst & Urbi, 1986). 2,4,5-Tri- methoxystyrene was found to react by an entirely different pathway, however. Only products resulting from oxidative dimerization of this substrate, 5,7,8- trimethoxy-l-(2,4,5-trimethoxyphenyl)-l,2-dihydro- naphthalene and some of the corresponding naphth- alene, were obtained in the presence of manganese(III) acetate. This result was particularly surprising in view of the possibility for solvolysis of radical-cation intermediates in acetic acid. We wish to describe in this paper the X-ray crystal structure determination, syn- thesis, and spectral characterization of the title com- pound.

Structure of bis(tetraphenylphosphonium) pentaselenide

P(C6Hs)4)2(Ses), Mr= 1073.6, monoclinic, P2~ (C2), a=9.573 (7), b= 16.945 (12), c= 13.563(10)A, fl=105.29(2) ° , V=2122(3)A 3, z = 2, D x = 1.68 g cm -3, Mo Ko., 2(Kay) = 0.7093 A, /z= 43.8 cm -~, F(000)= 1054.6 including anomalous dispersion, T= 123K, R(F 2)=0.075 for 3681 reflections. The Se 2- chain has a trans con- formation with short terminal and long internal Se-Se bonds of average lengths 2.315 (2) and 2.361 (2)A, respectively. The internal and the average terminal Se-Se-Se angles are 110.59 (7) and 108.93 (6) °, respectively. The Se(1) and Se(5)atoms are twisted out of the Se(2), Se(3), Se(4) plane by torsion angles of 77.32 (8) and 89.16 (7) ° , respectively. Introduction. Soluble salts of transition-metal selenium anions (MxS%) 2- are rare. We recently showed that selenation of ammonium metavanadate with bis(di- methyloctylsilyl) selenide produced the V2Se23 ion (Chau, Wardle & Ibers, 1987). As a continuation of our efforts to discover new transition-metal selenium anions we have investigated the reaction of zirconium tetra- ethoxide with bis(dimethyloctylsilyl) selenide. In an attempt to crystallize the resulting product, we obtained the title compound, presumably as a result of air- oxidation of a zirconium selenide anion. Here, we report its molecular structure and compare it with that of other Se 2- anions. Experimental. Dark-brown crystals of the title com- pound were obtained by slow diffusion of ether into a DMF solution of the product that resulted from the selenation of zirconium tetraethoxide by bis(dimethyl- octylsilyl) se|enide. The red powdery product was prepared by combining 0.1 g zirconium, 0.5 g zir- conium tetraethoxide, 0.2 g selenium, and 0.9 g tetra- phenylphosphonium chloride in 25 mL DMF with 1.5 g bis(dimethyloctylsilyl) selenide. After stirring overnight at room temperature the dark red-brown solution was filtered. Addition of ether caused the precipitation of the red powder; it was filtered, washed twice with ether, and suction dried. This material has an infrared absorption at 270 cm-L When the material was recrystallized to give the title compound this absorption peak dis- appeared, possibly because of decomposition. A very

1-(2,2'-Bipyridyl)-2-methyl-3-(trimethylsilyl)-2,3-dicarba-1-stanna-closo-heptaborane(6)

C 16 H 24 B 4 N 2 PbSi cristallise dans P1 avec a=7,007, b=9,318, c=16,462 A, α=103,84, β=96,40, γ=95,21 o , Z=2; affinement jusqu'a R=0,035. Dans la structure bipyramide pentagonale deformee, l'atome Pb du sommet est deplace vers les bore du dessus de la face C 2 B 3 . La bipyridine n'est pas exactement a l'oppose de la liaison C−C de la cage. Les longueurs des liaisons dans la structure cage sont Pb−C=2,835 et 2,770 A, Pb−B=2,466 a 2,601 A et Pb−N=2,615 et 2,663 A. L'empilement revele que les interactions intermoleculaires du type dipole-dipole dans le precurseur plumbacarborane ont ete brisees lors de la formation du complexe donneur-accepteur avec la base de Lewis, 2,2'-bipyridine

ChemInform Abstract: Molecular and Electronic Structure of Cu(tet‐b)SSCH2CO2 . 3CH3OH, a Novel Copper‐(II) Alkyl Persulfide Complex.

AbstractIn the reaction of [Cu(tet‐b)]2+, KOH, and HSCHZCOOH in MeOH under anaerobic conditions, the diamagnetic title com‐ pound (I) is formed instead of the expectedmercaptoacetate analogue Cu(tet‐ b) (SCH2COO).

Synthese und Struktur von Dicarbonyl(η5-pentaphenylcyclopentadienyl)rhodium, (η5-C5Ph5)Rh(CO)2

Abstract (η5-C5Ph5)Rh(CO)2 has been prepared in 62% yield by treatment of [Rh(CO)2Cl]2 with NaC5Ph5 in THF. The title com pound crystallizes in the rhombic space group Pcab with the lattice parameters a = 2064.7(7) pm , b = 2065.2(8) pm, c = 1407.6(6) pm and Z = 8 . The crystal structure consists of discrete (η5-C5Ph5)Rh(CO)2 molecules and the Rh(CO)2 fragment adopts an eclipsed conformation relative to the cyclopentadienyl ring.