Synthesis and crystal structure of 1,3,5-tris [4-(phenylethynyl)phenyl]benzene

The crystal structure of 1,3,5-tris[4-(phenylethynyl)phenyl]benzene (1) has been investigated. Compound1 represents a model of the repeating unit of the most typical polyphenylene, which contains 1,3,5-trisubstituted benzene rings (chain centers) and acetylenic groups (complex-forming and cross-linking centers) in the main chain. The acetylene groups of neighboring molecules have a tendency to close mutual arrangement, which is favorable for their topochemical interaction. However, the relative conformational rigidity of molecules1 restricts not only the possibility of the optimal adjustment of the reactive sites of neighboring molecules to one another, but also hampers the close packing of molecules in the crystal, which contains channels filled by the solvent molecules (chloroform).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1986–1992, November, 1994.The work was carried out with the financial support of the International Science Foundation and the American Crystallographic Association.     

The preparation and X-ray structural study of complexes that catalyze isocyanate cyclotrimerization

A 11-complex of trinitrophenol with benzyldimethylamine (1) and a 111-complex, the product of the interaction of benzyldimethylamine, glycidyl phenyl ether, and phenol (2), have been synthesized and characterized by means of X-ray analysis. Complex1 is a precursor for the catalysts of selective isocyanate cyclotrimerization, while complex2 is one of those catalysts. In the crystal structure complex1 forms H-bonded cationic-anionic aggregates with proton transfer from phenol to the N-atom of the tertiary amine. Complex2 crystallizes as a monohydrate (2a) with a strong H-bond between the quaternary ammonium and phenolic components, and exists in crystals in the form of globular H-bonded dimeric hydrates. Possible pathways of dissociation of complex2a are discussed. The data obtained may be used as a basis for further interpretation of the regularities of cyclotrimerization of isocyanates catalyzed by complexes of this type.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No 1, pp. 92–97, January, 1993.     

Molecular recognition of NO/NO+ via multicenter (charge-transfer) binding to bridged diarene donors. Effect of structure on the optical transitions and complexation thermodynamics

Bridged diarenes form very strong [1:1] complexes with nitrosonium/nitric oxide in which the NO moiety is optimally sandwiched in the cleft between a pair of cofacial aromatic rings which act as a molecular "Venus flytrap". The spectral features of these associates are generally similar to those for [1:1] and [2:1] nitrosonium complexes with mononuclear alkyl-substituted benzenes, and they are appropriately described within the LCAO molecular-orbital methodology and the Mulliken (charge-transfer) formulation of donor/acceptor electronic transitions. The thermodynamics study indicates that the efficient binding is determined by (i) the close matching of the donor/acceptor redox potentials and (ii) the ability of bridged diarenes for multicentered interactions with a single NO moiety. The best fit of the electronic and structural parameters is provided by a calixarene host that allows the interacting centers to be arranged in a manner similar to those extant in [2:1] nitrosonium complexes with analogous (nonbridged) aromatic donors; this results in its very strong noncovalent binding with nitrosonium/nitric oxide with the formation constant of K(B) approximately 10(8) M(-)(1) and free-energy change of -DeltaG degrees = 45 kJ mol(-)(1). Such strong, selective, and reversible bindings of nitrosonium/nitric oxide by (cofacial) aromatic centers thus provide the basis for the development of efficient NO sensors/absorbents and also suggest their potential relevance to biochemical systems.     

Synthesis and structure of 6-chloro-2,3-trimethylene-4-phenylquinoline

An X-ray structural investigation of 6-chloro- 2,3-trimethylene-4- phe nylquinoli ne obtained by the reaction of 2-amino-5-chlorobenzophenone with cyclopentanone was carried out. At 20 °C, a = 23.750,b = 9,242, c = 14.018 A, = 112,68° space group (21c,Z = 8, 2647 reflections,R = 0.047 He five-membered ring has an envelope conformation Conjugation between the quinohne fragment and the phenyl substituent is significantly distorted dm to the rotation of the latter by -62.9°Translated fromIzvestiya Akademii Nauk. Seriva Khimicheskaya, No. 7, pp. 1800–1802, July, 1996.     

Molecular and crystal structure of the sequiterpene lactone austricin

An x-ray structural study has been made of the sesquiterpene lactone austricin: diffractometer, MoK radiation, 1147 reflections, direct method, R=0.045. The spatial structure of the molecule has been determined. The conformation of the pentane carbocycle is 1-envelope, of the heptane ring 1,10, 7-chair, and of the lactone ring 7-envelope. The lactone ring is trans-linked with the guaiane skeleton.Institute of Organic Synthesis and Coal Chemistry, Kazakh SSR Academy of Sciences, Karaganda. A. N. Nesmeyanov Institute of Heteroorganic Compounds, USSR Academy of Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 788–791, November–December, 1989.     

Crystal and molecular structure of 2e-diethylamino-3e,4e-dimethyl-5e-phenyl-2a-thio-1,3,2-oxazaphospholane

The results of an x-ray structural investigation of 2e-diethylamino-3e,4e-dimethyl-5e-phenyl-2a-thio-1,3,2-oxazaphospholane are discussed. It has been shown that the conformation of the 5-membered ring is that of a half-chair.Institute of Organic Synthesis and Coal Chemistry, Kazkh SSR Academy of Sciences, Karganda. A. N. Nesmeyanov Institute of Heteroorganic Compounds, USSR Academy of Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 386–389, May–June, 1990.     

Crystal and molecular structure of hexacarbomethoxycyclopropane

A. N. Nesmeyanov Institute of Heteroorganic Compounds, Academy of Sciences of the USSR. N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 3, pp. 171–173, May–June, 1989.     

Molecular and crystal structure of the germacranolide argolide from Artemisia glabella

The new germacranolide argolide has been isolated from the epigeal part ofArtemisia glabella, and its structure has been shown by its conversion into oxopelenolide B. From the results of an x-ray investigation it is suggested that argolide has the spatial structure of 3-oxo-4α,7α,6β(H)-germacra-1(10),11(13)-dien-6,12-olide. Institute of Organic Synthesis and Coal Chemistry, Kazakh Academy of Sciences, Karaganda. A. N. Nesmeyanov Institute of Organometallic Chemistry, Russian Academy of Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 653–657, September–October, 1991.     

Molecular structure of 4,16-dichloro- and 4,16-dibromo[2.2]-paracyclophanes

Conclusions An x-ray diffraction structural analysis showed that the distortions in the geometries of sterically strained 4,16-dichloro- and 4,16-dibromo[2.2]paracyclophanes are similar to those found in unsubstituted [2.2]paracyclophane. The introduction of bulky halogen atoms at C⁴ and C¹⁶ in the [2.2]paracyclophane molecule does not lead to a marked increase in the steric repulsion of the benzene rings. The polar nature of the halogen atoms leads to dipole-dipole attraction of the antiparallel benzene rings which are drawn somewhat closer to each other and to the halogen atom of the other ring.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2007–2010, September, 1986.     

Carbocyclic and nitrogen-containing fused CH-acids with an annelated indenyl fragment. Thermogravimetric and X-ray structural analysis of 6H-indeno[1,2-b]quinoline

Based on thermogravimetric characteristics first obtained for the model 6H-indeno [1,2-b]quinoline, the scheme of thermal conversions of this compound in the temperature range 20–700 °C has been proposed, and the limit of its thermal stability (300 °C) has been determined. This temperature is recommended as the optimum for synthesizing fused benzoaza(diaza)fluorenes. Based on the results of X-ray structural analysis, the molecules of the studied indenoquinoline form centrosymmetric pairs, which are arranged in (110) layers. The molecules are orientationally disordered. The observed self-association of these molecules is similar to the - association of fused heterocyclic systems with-excessive and ****- deficient fragments. It has been suggested that interferon-inducing and antitumor compounds with an annelated indenyl fragment have a common mechanism of action according to the intercalation model of stacking structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 703–709, April, 1995.