2‐(3‐tert‐Butyldimethylsiloxy‐4‐methoxyphenyl)‐6‐methoxy‐3‐(3,4,5‐trimethoxybenzoyl)indole

In the crystal structure of the title compound, C₃₂H₃₉NO₇Si, all geometric parameters fall within experimental error of expected values. The analysis of molecular‐packing plots reveals an infinite two‐dimensional linear array running parallel to the b axis, formed by one N—H?O intermolecular hydrogen‐bonding interaction. Several potential C—H?O interactions are also present.     

(η6‐2‐Bromo‐1,1′‐biphenyl)tricarbonylchromium

The title compound, [Cr(C₁₂H₉Br)(CO)₃], crystallizes in the triclinic space group with close Br⋯Br separations. These contacts, along with several other factors, influence the (Ph)C—C(o‐BrC₆H₄) dihedral angle of 58.82 (6)°. The typical piano‐stool coordination about the Cr atom is in excellent agreement with the results of density functional theory calculations.     

[5‐Bromo‐N‐(2‐carboxylatophenyl)salicylideniminato]dimethyltin(IV)

The structure of the title di­methyl­tin(IV) complex, [2‐(5‐bromo‐2‐oxido­benzyl­idene­amino)­benzoato‐κ³O,N,O′]di­methyl­tin(IV), [Sn(CH₃)₂(C₁₄H₈BrNO₃)], features centrosymmetric dimers disposed about a central Sn₂O₂ core. Each Sn centre has seven‐coordinate pentagonal–bipyramidal geometry, taking into account two moderately long Sn—O contacts about an inversion centre [2.679 (4) and 2.981 (4) Å]. The methyl groups are in an axial orientation.     

Absolute configuration of (+)‐(S)‐2‐(5‐fluoro‐2‐methoxy‐1,4‐benzodioxan‐2‐yl)­imidazolinium bromide

The title compound, C₁₂H₁₄FN₂O₃⁺·Br^?, crystallizes in the non‐centrosymmetric P2₁2₁2₁ space group. The absolute configuration of the pharmacologically active mol­ecule could be resolved in the hydro­bromide salt, the structure of which is reported. The mol­ecule of the title compound has the S configuration. The molecular packing in the crystal is stabilized by weak N—H?Br [N?Br = 3.240 (4) and 3.302 (4) Å] hydrogen bonding.     

17β‐Ethoxy‐3‐methoxy‐8‐isoestra‐1,3,5(10)‐triene

The conformation of the crystal of 17β‐ethoxy‐3‐methoxy‐8‐iso­estra‐1,3,5(10)‐triene, C₂₁H₃₀O₂, (I), has been established and compared with the molecular structure of a typical steroid estrogen 8‐iso‐analogue, (II). Calculations of distances separating some of the H‐atom pairs in (I) and (II) by molecular‐mechanical and semi‐empirical methods revealed the similarity of the values to the H⃛H distances obtained from X‐ray analysis.     

Synthesis of 5‐(Arylselanyl)‐2‐(arylsulfanyl)benzoates by [3+3] Cyclocondensation of 3‐(Arylsulfanyl)‐1‐(silyloxy)buta‐1,3‐dienes with 2‐(Arylselanyl)‐3‐(silyloxy)alk‐2‐en‐1‐ones

Functionalized 5‐(arylselanyl)‐2‐(arylsulfanyl)benzoates were prepared by [3+3] cyclocondensation of 3‐(arylsulfanyl)‐1‐(silyloxy)buta‐1,3‐dienes with 2‐(arylselanyl)‐3‐(silyloxy)‐alk‐2‐en‐1‐ones.     

[1,1,2,2‐(CO)4‐1,2‐μ‐(CO)‐4,11‐(SMe2)2‐closo‐1,2‐Co2B10H8]

The title compound, 1,1,2,2‐tetra­carbonyl‐1,2‐μ‐carbonyl‐4,11‐di­methyl­sulfido‐closo‐1,2‐dicobaltadodecaborane, [Co₂(C₄H₂₀B₁₀S₂)(CO)₅], has a closo 12‐vertex {1,2‐Co₂B₁₀H₈} structure with SMe₂ ligands at the exo‐4‐ and 11‐positions. The cluster displays close structural similarities to the SEt₂ analogue.     

(+)‐(2R,3S)‐3‐Bromo‐2‐chloro‐N,N‐diiso­propyl‐3‐phenyl­propan­amide and (+)‐(2R,3S)‐3‐bromo‐2‐chloro‐N‐(4‐nitro­phenyl)‐3‐phenyl­propan­amide

The stereochemistries at positions 2 and 3 of the title compounds, C₁₅H₂₁BrClNO, (I), and C₁₅H₁₂BrClN₂O₃, (II), have been confirmed by X‐ray structural analysis. The halogen atoms adopt an antiperiplanar arrangement in each case.     

Ethyl 2‐form­amido‐2‐(4‐iodo­benzyl)‐3‐(4‐iodo­phenyl)­propionate and ethyl 2‐(3‐bromo­benzyl)‐3‐(3‐bromo­phenyl)‐2‐form­amidopropionate

The title compounds, C₁₉H₁₉I₂NO₃ and C₁₉H₁₉Br₂NO₃, are derivatives of α‐amino­isobutyric acid with halogen substituents at the para and meta positions, respectively. The ethoxycarbonyl and formamide side chains attached to the C_α atom of the mol­ecule adopt extended and folded conformations, respectively. The crystal structures are stabilized by N—H⃛O, C—H⃛O, C—Br⃛O and C—I⃛O interactions.     

3‐Methoxy‐5‐(4‐methyl­phenyl­diazenyl)­salicyl­aldehyde and 3‐methoxy‐5‐(2‐methyl­phenyl­diazenyl)­salicyl­aldehyde

The two title mol­ecules, both C₁₅H₁₄N₂O₃, are roughly planar and display a trans conformation with respect to the –N=N– double bond, as found for other diazene derivatives. In both compounds, there are intramolecular O—H⋯O hydrogen bonds and the crystal packing is governed by weak intermolecular C—H⋯O hydrogen bonds and π–π stacking.     

(E)‐2‐(2‐Adamantylidene)‐3‐(1‐ferrocenylethylidene)succinic anhydride

The title compound, [Fe(C₅H₅)(C₂₁H₂₁O₃)], was obtained from successive Stobbe condensations between ketones and di­methyl succinate. The succinic anhydride five‐membered ring is distorted significantly from planarity, with the buta­diene moiety being twisted by 49.3 (2)° from planarity and the C atoms at the succinic anhydride end of the alkene bonds showing significant pyramidalization. The cyclo­penta­diene rings of the ferrocenyl moiety adopt an almost eclipsed conformation.     

(E)‐3‐(Benzo[b]thiophen‐2‐yl)‐2‐(3,4,5‐trimethoxyphenyl)acrylonitrile and (Z)‐3‐(benzo[b]thiophen‐2‐yl)‐2‐(3,4‐dimethoxyphenyl)acrylonitrile

The title compounds, C₂₀H₁₇NO₃S, (I), and C₁₉H₁₅NO₂S, (II), were prepared by the reaction of benzo[b]thiophene‐2‐carbaldehyde with (3,4,5‐trimethoxyphenyl)acetonitrile and (3,4‐dimethoxyphenyl)acetonitrile, respectively, in the presence of methanolic potassium hydroxide. In (I), the C=C bond linking the benzo[b]thiophene and the 3,4,5‐trimethoxyphenyl units has E geometry, with dihedral angles between the plane of the bridging unit and the planes of the two adjacent ring systems of 5.2 (3) and 13.1 (2)°, respectively. However, in (II), the C=C bond has Z geometry, with dihedral angles between the plane of the bridging unit and the planes of the adjacent benzo[b]thiophene and 3,4‐dimethoxyphenyl units of 4.84 (17) and 76.09 (7)°, respectively. There are no significant intermolecular hydrogen‐bonding interactions in the packing of (I) and (II). The packing is essentially stabilized via van der Waals forces.     

Heterobimetallic Complexes: Substitution Effects in the [Tetracarbonylrhodiumbis{μ‐(diphenylphosphino)}{μ‐(η:η2‐(4‐diphenylphosphino‐κP)‐2‐methyl‐oxobutyl)}molybdenum](Mo‐Rh) System

Syntheses of the array of heterobimetallic complexes [(OC)₃M(μ‐PPh₂)₂(μ‐O‐C(CHMe(CH₂)₂PPh₂)RhL], M = Cr, Mo, W, L = ^tBuNC, are described, extending the previous study of the counterpart array for L = CO. A single crystal X‐ray structure determination is reported for the M = Mo adduct, enabling comparison with its previously reported L = CO counterpart, for which an improved redetermination is also reported. In the present complex the ^tBuNC ligand is found to be much more weakly bound (Rh‐C 2.026(5) Å) than the carbonyl group it displaces (Rh‐C 1.945(2) Å) with concomitant minor impact on the remainder of the rhodium ambience.     

Electrospinning of polystyrene/poly(2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylene vinylene) blends

Ultrafine polystyrene (PS)/poly(2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylene vinylene) (MEH‐PPV) fibers were successfully prepared by electrospinning of PS/MEH‐PPV solutions in chloroform, 1,2‐dichloroethane, and tetrahydrofuran (THF). Three concentrations of the solutions were prepared: 8.5, 16, and 23.5% (w/v), with the compositional weight ratios between PS and MEH‐PPV being 7.5:1, 15:1, and 22.5:1, respectively. Smooth fibers only observed from 23.5% (w/v) PS/MEH‐PPV solution in chloroform. Improvement in the electrospinnability of 8.5% (w/v) PS/MEH‐PPV solution in chloroform was achieved by addition of an organic salt, pyridinium formate (PF), or by addition of a minor solvent with a high dielectric constant value. The average diameters of the as‐spun PS/MEH‐PPV fibers were between 0.30 and 5.11 μm. Last, photoluminescence of 8.5% (w/v) solutions of PS/MEH‐PPV in a mixed solvent system of chloroform and 1,2‐dichloroethane of various volumetric compositions and the resulting as‐spun fibers was investigated and compared. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1881–1891, 2005     

[(8a,9,9a‐η)‐9‐(η5‐Cyclopentadienyl)‐9‐nickelafluorenyl](η5‐pentamethylcyclopentadienyl)nickel(II)

The title compound, [Ni₂(C₅H₅)(C₁₀H₁₅)(C₁₂H₈)] or [Ni(C₁₀H₁₅){Ni(C₅H₅)(C₁₂H₈)}], is a rare example (and the first obtained from nickelafluorenyllithium) of an analogue of nickelocene in which the central Ni atom is coordinated to one pentamethylcyclopentadienyl ring and one nickelafluorenyl ring. Both rings lie almost parallel to one another: the dihedral angle between the planes which include these rings is 4.4 (1)°. Slip parameter analysis indicates that the bonding mode of the central Ni atom to the nickelacyclic ring is between η³ and η⁵. Two‐dimensional layers of molecules are formed by C—H...π interactions.     

Regioselective Lactonization of α‐(2→8)‐Trisialic Acid

A simple and selective method has been developed to obtain both monolactones of the title compound, a model compound for biologically important polyneuraminic acid derivatives: acidic lactonization and alkaline hydrolysis of dilactone 1 . The two monolactonized trimers can be separated by capillary electrophoresis, and then distinguished by enzymatic hydrolysis with neuraminidase; only the 2‐monolactone undergoes reaction.     

(4‐Bromo‐2‐formyl­phenolato)­perchlorato­(1,10‐phenanthroline)­copper(II)

In the title copper(II) compound, [Cu(C₇H₄BrO₂)(ClO₄)(C₁₂H₈N₂)], the Cu atom is five‐coordinated in a distorted square‐pyramidal geometry by the N‐ and O‐donors of 4‐bromo‐2‐formyl­phenolate, 1,10‐phenanthroline and perchlorate. Pairs of complexes are linked together by Cu⋯O(phenolate) and π–π stacking inter­actions between 4‐bromo‐2‐formyl­phenolate and 1,10‐phenanthroline. Along the crystallographic a axis, the dimers are linked by hydrogen bonds between a perchlorate O atom and a 4‐bromo‐2‐formyl­phenolate H atom, and by further π–π stacking inter­actions. Hydrogen bonding between the Br atom and a 1,10‐phenanthroline H atom takes place between the stacks of dimers.     

Synthesis and Crystal Structure of [1‐(η5‐9‐Fluorenyl)‐2‐(η5‐1‐indenyl)ethane]hafnium Dimethyl

The synthesis and characterization of the unsymmetric hafnium dialkyl [1‐(η⁵‐9‐fluorenyl)‐2‐(η⁵‐1‐indenyl)ethane]HfCl₂ ( 2 ) and corresponding dimethyl complex [1‐(η⁵‐9‐fluorenyl)‐2‐(η⁵‐1‐indenyl)ethane]Hf(CH₃)₂ ( 3 ) is described. The dialkyl hafnocene ( 3 ) crystallizes in monoclinic space group P2₁/c (No. 14) with a = 9.458(8), b = 8.541(8), c = 23.733(11) Å, β = 93.16(5) deg., V = 1914(3) ų, Z = 4. Further on, complex 3 was activated with methylaluminiumoxane (MAO) and utilized as a catalyst in ethene polymerization.