Aqua­nitro(α,β,γ,δ‐tetra­phenyl­porphy­rinato)­cobalt(III) N,N‐di­methyl­form­amide disolvate

In the title compound, [Co(tpp)(NO₂)(H₂O)]·2dmf or [Co(C₄₄H₂₈N₄)(NO₂)(H₂O)]·2C₃H₇NO, a distorted octahedral Co^III complex shows an orientational disorder such that the positions of the nitro and aqua ligands are exchanged. As a result, the averaged structure has an inversion centre at the Co atom. The di­methyl­form­amide mol­ecule also has a positional disorder.     

2,4‐Bis(α,α‐di­methyl­benzyl)­phenol

The structure of the title compound, 2,4‐bis(1‐methyl‐1‐phenylethyl)phenol, C₂₄H₂₆O, was found to have a torsion angle of 129.95 (13)° for the C—C bond that connects the benzyl carbon to the phenol ring ortho to the OH group. A value of ～50° was expected from molecular mechanics calculations. Intermolecular interactions, in particular O—H?O and edge–face π bonding, may contribute to this discrepancy. Intramolecular O—H?π bonding is also observed.     

Cyclo(l‐leucyl‐α,β‐dehydro­phenyl­alanine): the first diketopiperazine containing an α,β‐dehydro­phenyl­alanine residue

The title compound (systematic name: 3‐benzyl­idene‐6‐iso­butyl­piperazine‐2,5‐dione), C₁₅H₁₈N₂O₂, an α,β‐dehydro­phenyl­alanine containing diketopiperazine, crystallizes in the space group P1 with two mol­ecules in the asymmetric unit arranged antiparallel to one another. The α,β‐dehydro­phenyl­alanine (ΔPhe) residue in this cyclic peptide retains its planarity but deviates from the standard conformations observed in its linear analogues. Each type of mol­ecule forms a linear chain with mol­ecules of the same type via pairwise N—H⋯O hydrogen bonds, while weaker C—H⋯O inter­actions link the chains together to form a three‐dimensional network.     

Oleana‐12(13),15(16)‐diene‐3α,28‐diyl di­acetate

The title compound, C₃₄H₅₂O₄, consists of five six‐membered rings. Barring the two rings, with double bonds, all other rings are in chair conformations. Mean‐plane and ring‐puckering calculations indicate these two rings to be in distorted‐chair conformations, with distortion towards the boat conformation. There are no strong hydrogen bonds and the structure is stabilized by van der Waals interactions only. The structure is compared with those reported for other triterpenes.     

3β‐Acetoxy‐5α,6β‐di­hydroxybisnorcholanic acid 2216 lactone

In the title compound, C₂₄H₃₆O₆, the ester linkage in ring A is equatorial. The six‐membered rings A, B and C have chair conformations. The five‐membered ring D adopts a 13β,14α‐half‐chair conformation and the E ring adopts an envelope conformation. The A/B, B/C and C/D ring junctions are trans, whereas the D/E junction is cis.     

(n‐Butyl­di­phenyl­phosphine)­di­chloro(η6‐p‐cymeme)­ruthenium(II)

The title ruthenium complex, [RuCl₂(C₁₀H₁₄)(C₁₆H₁₉P)], contains a monodentate (C₄H₉)PPh₂ ligand coordinated by the P atom. Coordination about the metal centre is completed by a η⁶‐p‐cymene ligand and two Cl atoms.     

A moderate distortion of the `picket‐fence' porphyrin (cryptand‐222)potassium chlorido[meso‐α,α,α,α‐tetrakis(o‐pivalamidophenyl)porphyrinato]ferrate(II) n‐hexane monosolvate

As representative porphyrin model compounds, the structures of `picket‐fence' porphyrins have been studied intensively. The title solvated complex salt {systematic name: (4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane)potassium(I) [5,10,15,20‐tetrakis(2‐tert‐butanamidophenyl)porphyrinato]iron(II) n‐hexane monosolvate}, [K(C₁₈H₃₆N₂O₆)][Fe(C₆₄H₆₄N₈O₄)Cl]·C₆H₁₄ or [K(222)][Fe(TpivPP)Cl]·C₆H₁₄ [222 is cryptand‐222 or 4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane, and TpivPP is meso‐α,α,α,α‐tetrakis(o‐pivalamidophenyl)porphyrinate(2−)], [K(222)][Fe(TpivPP)Cl]·C₆H₁₄, is a five‐coordinate high‐spin iron(II) picket‐fence porphyrin complex. It crystallizes with a potassium cation chelated inside a cryptand‐222 molecule; the average K—O and K—N distances are 2.81 (2) and 3.05 (2) Å, respectively. One of the protecting tert‐butyl pickets is disordered. The porphyrin plane presents a moderately ruffled distortion, as suggested by the atomic displacements. The axial chloride ligand is located inside the molecular cavity on the hindered porphyrin side and the Fe—Cl bond is tilted slightly off the normal to the porphyrin plane by 4.1°. The out‐of‐plane displacement of the metal centre relative to the 24‐atom mean plane (Δ₂₄) is 0.62 Å, indicating a noticeable doming of the porphyrin core.     

N‐[tert‐Butoxy­carbonyl­glycyl‐(Z)‐α,β‐dehydro­phenyl­alanylglycyl‐(E)‐α,β‐dehydro­phenyl­alanylphenyl­alanyl]‐4‐nitro­aniline ethanol solvate

The α,β‐dehydro­phenyl­alanine residues influence the conformation of the title penta­peptide Boc⁰–Gly¹–Δ^ZPhe²–Gly³–Δ^EPhe⁴–l ‐Phe⁵–p‐NA ethanol solvate, C₄₂H₄₃N₇O₉·C₂H₅OH. The first unsaturated phenyl­alanyl (Δ^ZPhe²) and the third glycyl (Gly³) residues form a type I β turn, while the second unsaturated phenyl­alanyl (Δ^EPhe⁴) and the last phenyl­alanyl (l ‐Phe⁵) residues are part of a type II β turn. All the amino acids in the peptide are linked trans to one another. The crystal structure is stabilized by intra‐ and inter­molecular hydrogen bonds.     

1‐Methyl‐5,6‐di­phenyl­pyrazine‐2(1H)‐thione

The title compound, C₁₇H₁₄N₂S, crystallizes in a triclinic unit cell, with two crystallographically independent mol­ecules in the asymmetric unit. The two independent mol­ecules pack in the same sense and form segregated layers along the c axis. The crystal is light‐stable and no dimers are formed under irradiation. The intermolecular distances between the potential reactive centers (the C‐3 and C‐5 ring positions) are 4.093 (4) and 5.643 (4) Å for mol­ecule A, and 4.081 (4) and 5.614 (4) Å for mol­ecule B.     

Photoimageable polyimides derived from α,α‐(4‐amino‐3,5‐dimethylphenyl)phenylmethane and aromatic dianhydride

Soluble and inherent photoimageable polyimides with improved photopatterning features were prepared from α,α‐(4‐amino‐3,5‐dimethylphenyl)phenylmethane and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride. The polyimides possessed good combined chemical and physical properties: thermal stability was observed, with an initial thermal decomposition temperature of 565 °C and a high glass‐transition temperature of 318 °C. Homogeneous polyimide solutions in common organic solvents with solid contents as high as 20 wt % were prepared. These solutions had a shelf life greater than 3 months. The polyimides had high electric insulating properties and low dielectric constants and dissipation factors. Fine patterns were processed by direct exposure of the polyimide coatings to UV i‐line, followed by development with an organic developer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3012–3020, 2002     

Lipophilic Functionalized Cobyrinic-Acid Derivatives. Part 1. Cobester α-monoacids (α,α,α,β,β,β-hexamethyl α-hydrogen Coα, Coβ-dicyanocobyrinates)

The four α,α,α, β,β,β,-hexamethyl α-hydrogen Coα, Coβ-dicyanocobyrinates 2b, d–f , with a free b-, d-, e-, and f-propionic-acid function, respectively, were prepared by partial hydrolysis of heptamethyl Coα, Coβ-dicyanocobyrinate (cobester; 1 ) in aqueous sulfuric acid. The cobester monoacids 2b, d–f were obtained as a ca. 1:1:1:1 mixture which was separated. The monoacids were purified by chromatography and isolated in crystalline form. The position of the free propionic-acid function was determined by an extensive analysis of 2b, d–f using 2D-NMR techniques; an analysis of the C,H-coupling network topology resulted in an alternative assignment strategy for cobyrinic-acid derivatives, based on pattern recognition. Additional information on the structure of the most polar of the four hexamethyl cobyrinates, of the b-isomer 2b , was also obtained in the solid state from a single-crystal X-ray analysis. Earlier structural assignments based on 1D-NMR spectra of the corresponding regioisomeric monoamides 3b, d–f (obtained from crystalline samples of the monoacids 2b, d–f ) were confirmed by the present investigations.     

(–)‐(S)‐2‐(Fluoro­di­phenyl­methyl)­pyrrolidinium chloride

The title compound, C₁₇H₁₉FN⁺·Cl^?, has an ionic structure, and cations and anions are linked into infinite chains by Cl?H—N—H?Cl hydrogen bonds. The absolute configuration (S) was confirmed.     

2′,4′‐Di­hydroxy‐3‐methoxy‐α,β‐di­hydro­chalcone and 2′,4‐di­hydroxy‐α,β‐di­hydro­chalcone: supramolecular structures formed by O—H⋯O,C—H⋯O and stacking interactions

The crystal structures of 2′,4′‐di­hydroxy‐3‐methoxy‐α,β‐di­hydro­chalcone, C₁₆H₁₆O₄, and 2′,4‐di­hydroxy‐α,β‐di­hydro­chalcone, C₁₅H₁₄O₃, have been determined. In both compounds, the structure consists of two nearly planar six‐membered aromatic rings connected by a propanal chain, which is bent in the methoxy compound and almost straight in the other compound. In the crystal structures, the molecular units of both compounds are linked by O—H⋯O hydrogen bonds to form infinite one‐dimensional chains. Hydro­gen bonds and C—H⋯O contacts in the crystal structures were studied by topological analysis of charge density based on Hartree–Fock calculations. Almost all of the investigated C—H⋯O contacts should be characterized as weak hydrogen bonds.     

3‐(4‐Chloro­benzoyl)‐7‐(N,N‐di­methyl­amino)‐1‐phenyl­indolizine and 3‐(2,4‐di­chloro­benzoyl)‐7‐(N,N‐di­methyl­amino)‐1‐phenyl­indolizine

In both of the title compounds, C₂₃H₁₉ClN₂O, (I), and C₂₃H₁₈Cl₂N₂O, (II), the molecular packing is influenced by weak intermolecular C—H⋯O and C—H⋯π interactions, but despite the chemical similarity of the compounds, the packing in (II) is entirely different from that observed in (I).     

(4S,5S)‐(+)‐4‐Hydro­xy­methyl‐2,5‐di­phenyl­oxazoline

The absolute configuration of the title compound, alter­natively called (+)‐(4,5‐di­hydro‐2,5‐di­phenyl­oxazol‐4‐yl)­methanol, C₁₆H₁₅NO₂, has been confirmed as 4S,5S. The hydroxy­methyl group and phenyl ring at the asymmetric C atoms exhibit β and α orientations, respectively. The exocyclic C—C bonds at the asymmetric C atoms are mutually anticlinal (?ac). The hydroxyl group and the N atom of the oxazoline ring are involved in an intermolecular hydrogen bond leading to chains of mol­ecules.