Axially Chiral Selectors of C2 Symmetry Bound to Silica: Synthesis and HPLC-Evaluation

Ullmann dimerization of substituted methyl 3-X-1-benzothiophene-2-carboxylates 1-7 (X = Cl, Br) gave rise to the corresponding dimeric 3,3'-bi(1-benzothiophene) esters 8-13. Resolution of the title acid 20 by fractional crystallization of its mono- and bisquininium salt afforded pure (R)- and (S)-enantiomers, the optical purity and absolute configuration of which was confirmed by CD spectrometry and by X-ray crystallography. Ullmann dimerization of chiral oxazolines 23 and 24 derived from 2 proceeded without any diastereodifferentiation. Reduction of (R)- and (S)-20 afforded the corresponding (R)- and (S)-diols 29, which served as chiral ligands in a model enantioselective reduction of acetophenone. (R)- and (S)-1-phenylethan-1-ol were formed in 28 and 29% e.e., respectively.

Download Full-text

Chemically Fueled Assembly of Macrocycles Comprising Multiple Transient Bonds

10.26434/chemrxiv.11426007.v1 ◽

2019 ◽

Author(s):

Mohammad Mosharraf Hossain ◽

Joshua Atkinson ◽

Scott Hartley

Keyword(s):

Covalent Bond ◽

Dicarboxylic Acids ◽

Molecular Assembly ◽

Chemical Systems ◽

Complex Architectures ◽

The Creation ◽

Dynamic Exchange

Dissipative (nonequilibrium) assembly powered by chemical fuels has great potential for the creation of new adaptive chemical systems. However, while molecular assembly at equilibrium is routinely used to prepare complex architectures from polyfunctional monomers, species formed out of equilibrium have, to this point, been structurally very simple. In most examples the fuel simply effects the formation of a single transient covalent bond. Here, we show that chemical fuels can assemble bifunctional components into macrocycles containing multiple transient bonds. Specifically, dicarboxylic acids give aqueous dianhydride macrocycles on treatment with a carbodiimide. The macrocycle is assembled efficiently as a consequence of both fuel-dependent and -independent mechanisms: it undergoes slower decomposition, building up as the fuel recycles the components, and is a favored product of the dynamic exchange of the anhydride bonds. These results create new possibilities for generating structurally sophisticated out-of-equilibrium species.

Download Full-text

Chemically Fueled Assembly of Macrocycles Comprising Multiple Transient Bonds

10.26434/chemrxiv.11426007 ◽

2019 ◽

Author(s):

Mohammad Mosharraf Hossain ◽

Joshua Atkinson ◽

Scott Hartley

Keyword(s):

Covalent Bond ◽

Dicarboxylic Acids ◽

Molecular Assembly ◽

Chemical Systems ◽

Complex Architectures ◽

The Creation ◽

Dynamic Exchange

Dissipative (nonequilibrium) assembly powered by chemical fuels has great potential for the creation of new adaptive chemical systems. However, while molecular assembly at equilibrium is routinely used to prepare complex architectures from polyfunctional monomers, species formed out of equilibrium have, to this point, been structurally very simple. In most examples the fuel simply effects the formation of a single transient covalent bond. Here, we show that chemical fuels can assemble bifunctional components into macrocycles containing multiple transient bonds. Specifically, dicarboxylic acids give aqueous dianhydride macrocycles on treatment with a carbodiimide. The macrocycle is assembled efficiently as a consequence of both fuel-dependent and -independent mechanisms: it undergoes slower decomposition, building up as the fuel recycles the components, and is a favored product of the dynamic exchange of the anhydride bonds. These results create new possibilities for generating structurally sophisticated out-of-equilibrium species.

Download Full-text

Reactions of macroions with ester and carboxylic groups of polymers

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19872194 ◽

1987 ◽

Vol 52 (9) ◽

pp. 2194-2203

Author(s):

Miloslav Kučera ◽

Dušan Kimmer ◽

Karla Majerová ◽

Josef Majer

Keyword(s):

Maleic Anhydride ◽

Acrylic Acid ◽

Methyl Methacrylate ◽

Bond Formation ◽

Covalent Bond ◽

The Other ◽

Poly Methyl Methacrylate ◽

Other Hand ◽

Carboxylic Groups ◽

Poly Acrylic Acid

In the reaction of dianions with poly(methyl methacrylate), only an insignificant amount of insoluble crosslinked product is obtained. If, however, the concentration of grafting dianions approaches that of ester groups, the amount of poly(methyl methacrylate) which may thus be crosslinked becomes quite significant. Dications, too, can bring about crosslinking of only an insignificant number of poly(methyl methacrylate) chains. Carboxylic groups in poly(acrylic acid) react with dianions and dications in an anhydrous medium similarly to ester groups. On the other hand, in the presence of a cocatalytic amount of water dications are more readily bound to carboxylic groups, forming a covalent bond. The relatively highest efficiency was observed in the bond formation between dication and the poly[styrene-alt-(maleic anhydride)], both in an anhydrous medium and in the presence of H2O.

Download Full-text

IR and 13C, 17O, and 119Sn NMR spectra of some bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19911908 ◽

1991 ◽

Vol 56 (9) ◽

pp. 1908-1915 ◽

Cited By ~ 18

Author(s):

Jaroslav Holeček ◽

Antonín Lyčka ◽

Milan Nádvorník ◽

Karel Handlíř

Keyword(s):

Infrared Spectroscopy ◽

Nmr Spectroscopy ◽

Dicarboxylic Acid ◽

Nmr Spectra ◽

Dicarboxylic Acids ◽

119Sn Nmr ◽

Carboxylic Groups ◽

Cyclic Oligomers ◽

The Media ◽

Oxygen Atoms

Infrared spectroscopy and multinuclear (13C, 17O, and 119Sn NMR spectroscopy have been used to study the structure of bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids (1-C4H9)2. Sn(X(COO)2), where X = (CH2)n (n = 0-8), CH=CH (cis and trans) and C6H4 (ortho and para).The crystalline compounds are formed by linear or cyclic oligomers or polymers whose basic building units represent a grouping composed of the central tin atom substituted by two 1-butyl groups and coordinated with both oxygen atoms of two anisobidentate carboxylic groups derived from different molecules of a dicarboxylic acid. The environment of the tin atom has a shape of a trapezoidal bipyramid. When dissolvet in non-coordinating solvents, the compounds retain the oligomeric character with unchanged structure of environment of the central tin atom. In the media of coordinating solvents the bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids form complexes whose central hexacoordinated tin atom binds two molecules of the solvent trough their donor atoms. Carboxylic groups form monodenate linkages in these complexes.

Download Full-text

Crystal structures of (S)- and (R,S)-2,2′-bipyridine-3,3′-dicarboxylic acid 1,1′-dioxides and of their barium salts: absolute configuration and molecular distortion enforced by supramolecular self-assembly

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1524/zkri.1997.212.3.226 ◽

1997 ◽

Vol 212 (3) ◽

Cited By ~ 7

Author(s):

P. Vojtíšek ◽

I. Císařová ◽

J. Podlaha ◽

Z. Žák ◽

S. Böhm ◽

...

Keyword(s):

Single Crystal ◽

Dicarboxylic Acid ◽

Crystal Structures ◽

Absolute Configuration ◽

Self Assembly ◽

Barium Salt ◽

X Ray Diffraction ◽

X Ray

AbstractCrystal structures of the title compounds were determined by single crystal X-ray diffraction. Absolute configuration of the barium salt of (+)-(

Download Full-text

CO-ORDINATION COMPLEXES OF TITANIUM (IV) HALIDES: II. PREPARATION AND INFRARED SPECTRA OF THE COMPLEXES OF TITANIUM TETRACHLORIDE WITH DIESTERS OF α,ω-DICARBOXYLIC ACIDS AND COMPARISON WITH ANALOGOUS COMPLEXES OF ZIRCONIUM TETRACHLORIDE AND TIN TETRACHLORIDE

Canadian Journal of Chemistry ◽

10.1139/v61-312 ◽

1961 ◽

Vol 39 (11) ◽

pp. 2343-2352 ◽

Cited By ~ 12

Author(s):

Ernest Rivet ◽

Real Aubin ◽

Roland Rivest

Keyword(s):

Molecular Weight ◽

Infrared Spectra ◽

Titanium Tetrachloride ◽

Complex Molecule ◽

Dicarboxylic Acids ◽

The Other ◽

Zirconium Tetrachloride ◽

Melting Points ◽

Zirconium Complexes ◽

Tin Tetrachloride

Co-ordination complexes between diesters of α,ω-dicarboxylic acids and titanium tetrachloride, tin tetrachloride, and zirconium tetrachloride have been prepared. The analytical results, the infrared spectra, the melting points, and the molecular-weight determinations indicate that for the titanium and zirconium complexes, two types of complexes are obtained, one having a general formula MX4•1 diester in which chelate rings from five to nine atoms are formed and the other one, 2MX4•1 diester in which there are two 4-membered rings per complex molecule. With tin tetrachloride only one type of complex is formed, which has two tin tetrachlorides and two diesters per complex molecule.

Download Full-text