Home About us Contact
|
Home About us Contact | ||
|
|
||
Versatile Building Block (versatile + building_block)
Selected AbstractsSupramolecular Chemistry Based on [W3S4(H2O)6Cl3]+ , A Versatile Building BlockEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2004Maxim N. Sokolov Abstract The cluster [W3S4(H2O)6Cl3]+ (which is present in solutions of [W3S4(H2O)9]4+ in 1,4 M HCl) reacts with the macrocyclic cavitand cucurbituril (C36H36N24O12) to form supramolecular adducts of 2:1 cluster/cucurbituril stoichiometry, where two portals of cucurbituril (which contains a water molecule in its cavity) are closed by two cluster cations. These aggregates are bound together in the solid by complementary hydrogen bonds between coordinated Cl, and the cations H9O4+ to give chains. Thus, a supramolecular architecture is achieved from three different but complementary building blocks. The packing of the chains affords a honeycomb structure (hexagonal symmetry) with channels (about 5.2 Å in diameter). The overall stoichiometry is (H9O4){[W3S4(H2O)6Cl3]2(C36H36N24O12)}Cl3·16.15H2O (1). [W3S4(H2O)6Cl3]+ reacts with SbCl3 in 6 M HCl to give cuboidal [W3(SbCl3)S4(H2O)6Cl3]+, which forms with the macrocyclic cavitand cucurbituril a 2:1 cluster/cucurbituril adduct , a discrete supramolecule consisting of five independent molecular units. In the solid it crystallizes as a salt of very rare anion [SbCl6]3, with the stoichiometry {[W3(SbCl3)S4(H2O)6Cl3]2(C36H36N24O12)}(SbCl6)2/3·12H2O (2). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Isocorannulenofuran: A Versatile Building Block for the Synthesis of Large Buckybowls.CHEMINFORM, Issue 15 2007Andrzej Sygula Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Usymmetrical Polyheteropolyene: A Versatile Building Block for the Preparation of Pyrrolo[2,1-b]thiazoles and 2H-Thiopyrano[2,3-b]pyridines.CHEMINFORM, Issue 1 2007Cyrille Landreau Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Stereoselective Synthesis of Alkynyl C-2-Deoxy-,-D-ribofuranosides via Intramolecular Nicholas Reaction: A Versatile Building Block for Nonnatural C-Nucleosides.CHEMINFORM, Issue 29 2003Masayoshi Takase Abstract For Abstract see ChemInform Abstract in Full Text. [source] 5,6-Bis(trimethylsilyl)benzo[c]furan: An Isolable Versatile Building Block for Linear Polycyclic Aromatic Compounds.CHEMINFORM, Issue 2 2003Siu-Hin Chan No abstract is available for this article. [source] Chelating Dialkoxide Titanium Complex: A Versatile Building Block for the Construction of Heterometallic DerivativesCHEMISTRY - A EUROPEAN JOURNAL, Issue 10 2007Rosa Fandos Dr. Abstract The heterometallic complex [TiCp*(O2Bz)2AlMe2] (2) has been synthesised by reaction of [TiCp*(O2Bz)(OBzOH)] (1) with AlMe3 (Cp*=,5 -C5Me5; Bz=benzyl). Complex 1 reacts with HOTf to yield the cationic derivative [TiCp*(OBzOH)2]OTf (3) (HOTf=HSO3CF3). Compound 3 reacts with [{M(,-OH)(cod)}2] (M=Rh, Ir; cod=cyclooctadiene) to render the early,late heterometallic complexes [TiCp*(O2Bz)2{M(cod)}2]OTf (M=Rh (4); Ir (5)). The molecular structure of complex 4 has been established by single-crystal X-ray diffraction studies. [source] ChemInform Abstract: Synthesis of Versatile Building Blocks Through Asymmetric Hydrogenation of Functionalized Itaconic Acid Mono-Esters.CHEMINFORM, Issue 21 2008Koen F. W. Hekking Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Efficient Formation of Novel and Versatile Building Blocks from Mucohalic Acids: New Substitute for Tetronic Acid and ,-Alkylidenebutenolide.CHEMINFORM, Issue 52 2005Ji Zhang Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Design and Synthesis of Porphyrins Bearing Rigid Hydrogen Bonding Motifs: Highly Versatile Building Blocks for Self-Assembly of Polymers and Discrete Arrays.CHEMINFORM, Issue 11 2002Xinxu Shi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] S- Thiazolinyl (STaz) Glycosides as Versatile Building Blocks for Convergent Selective, Chemoselective, and Orthogonal Oligosaccharide SynthesisCHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2006Papapida Pornsuriyasak Abstract In the aim of developing new procedures for efficient oligosaccharide assembly, a range of S- thiazolinyl (STaz) glycosides have been synthesized. These novel derivatives were evaluated against a variety of reaction conditions and were shown to be capable of being chemoselectively activated in the armed,disarmed fashion. Moreover, the S- thiazolinyl moiety exhibited a remarkable propensity for selective activation over other common leaving groups. Conversely, a variety of leaving groups could be selectively activated over the STaz moiety, which, in turn, allowed STaz/S- ethyl and STaz/S- phenyl orthogonal approaches. To demonstrate versatility of novel STaz derivatives, a number of oligosaccharide targets have been synthesized in a convergent selective, orthogonal, and chemoselective fashion. [source] Photoresponsive Self-Assembly and Self-Organization of Hydrogen-Bonded Supramolecular TapesCHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2006Shiki Yagai Dr. Abstract Self-assembling building blocks that are readily functionalizable and capable of achieving programmed hierarchical organization have enabled us to create various functional nanomaterials. We have previously demonstrated that N,N, -disubstituted 4,6-diaminopyrimidin-2(1,H)-one (DAP), a guanine,cytosine hybridized molecule, is a versatile building block for the creation of tapelike supramolecular polymer species in solution. In the current study, DAP was functionalized with azobenzene side chains. 1H NMR, UV/Vis, and dynamic light scattering studies confirmed the presence of nanometer-scale tapelike supramolecular polymers in alkane solvents at micromolar regimes. At higher concentrations (millimolar regimes), the supramolecular polymers hierarchically organized into lamellar superstructures to form organogels, as shown by X-ray diffraction and polarized optical microscopy. Remarkably, the azobenzene side chains are photoisomerizable even in the supramolecular polymers, owing to their loosely packed state supported by the rigid hydrogen-bonded scaffold, enabling us to establish photocontrollable supramolecular polymerization and higher order organization of the tapelike supramolecular polymers into lamellar superstructures. [source] Zinc-Salen-Catalyzed Asymmetric Alkynylation of Alkyl AcylsilanesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Feng-Quan Li Abstract Optically active tertiary propargylic alcohols are useful and versatile building blocks in organic synthesis, and their direct access by enantioselective addition of alkyne nucleophiles to ketones has achieved significant progress over the last ten years. In view of the potential applications of acylsilanes as useful synthetic equivalents of aldehydes, we described a general catalytic enantioselective addition of terminal alkynes to alkyl acylsilanes. After reaction optimization involving variation of solvent, temperature, catalyst ratio and various catalysts screen, the in situ generated Zn-salen complex was chosen as catalyst. With hexane as solvent, the silylated tertiary propargylic alcohols were obtained in satisfactory yields and ees for both aliphatic and aromatic alkynes. [source] | ||||||||||