scholarly journals Crystal engineered acid-base complexes with 2d and 3d hydrogen bonding systems using p-hydroxybenzoic acid as the building block

2010 ◽  
Vol 75 (4) ◽  
pp. 459-473 ◽  
Author(s):  
Pu Zhao ◽  
Xian Wang ◽  
Fang Jian ◽  
Jun Zhang ◽  
Lian Xiao
Keyword(s):  
Self Assembly ◽  
Building Block ◽  
Three Dimensional ◽  
Hydroxybenzoic Acid ◽  
Acid Base ◽  
3D Network ◽  
Acid And Base ◽  
Butyl Amine ◽  
Bonding Systems ◽  
Simply Connected

p-Hydroxybenzoic acid (p-HOBA) was selected as the building block for self-assembly with five bases, i.e., diethylamine, tert-butyl amine, cyclohexylamine, imidazole and piperazine, and generate the corresponding acid-base complexes 1-5. Crystal structure analyses suggest that proton-transfer from the carboxyl hydrogen to the nitrogen atom of the bases can be observed in 1-4; while only in 5 does a solvent water molecule co-exists with p-HOBA and piperazine. With the presence of O-H?O hydrogen bonds in 1-4, the deprotonated p-hydroxybenzoate anions (p-HOBAA-) are simply connected each other in a head-to-tail motif to form one-dimensional (1D) arrays, which are further extended to distinct two-dimensional (2D) (for 1 and 4) and three-dimensional (3D) (for 2 and 3 ) networks via N-H?O interactions. While in 5, neutral acid and base are combined pair wise by O-H?N and N-H?O bonds to form a 1D tape and then the 1D tapes are sequentially combined by water molecules to create a 3D network. Some interlayer or intralayer C-H?O, C-H?? and ??? interactions help to stabilize the supramolecular buildings. Melting point determination analyses indicate that the five acidbase complexes are not the ordinary superposition of the reactants and they are more stable than the original reactants.

A ‘Building Block’ Approach To Mixed-Colloid Systems Through Electrostatic Self-Organization

2001 ◽  
Vol 676 ◽  
Author(s):  
Trent H. Galow ◽  
Andrew K. Boal ◽  
Vincent M. Rotello
Keyword(s):  
Particle Size ◽  
Self Assembly ◽  
Building Block ◽  
Acid Base ◽  
Electrostatic Assembly ◽  
Polymer Colloid ◽  
Colloid Systems ◽  
Carboxylic Acid Derivative ◽  
Block Approach ◽  
Shape And Size

ABSTRACTWe have developed a highly modular electrostatically-mediated approach to colloid-colloid and polymer-colloid networks using ‘building block’ and ‘bricks and mortar’ self-assembly methodologies, respectively. The former approach involved functionalization of one type of nanoparticle building block with a primary amine and a counterpart building block with a carboxylic acid derivative. After combining these two systems, acid-base chemistry followed by immediate charge-pairing resulted in the spontaneous formation of electrostatically-bound mixed-nanoparticle constructs. The shape and size of these ensembles were controlled via variation of particle size and stoichiometries. In the ‘bricks and mortar’ approach, a functionalized polymer is combined with complementary nanoparticles to provide mixed polymer-nanoparticle networked structures. A notable feature is the inherent porosity resulting from the electrostatic assembly. The shape and size of these ensembles were controlled via variation of particle size, stoichiometries and the order in which they were added.

The effect of the coordination orientation of N atoms on polymeric structures: synthesis and characterization of one- and two-dimensional CuII coordination polymers based on 4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole

2019 ◽  
Vol 75 (4) ◽  
pp. 443-450
Author(s):  
Guiying Zhu ◽  
Yang Lu ◽  
Guoxia Jin ◽  
Xuan Ji ◽  
Jianping Ma
Keyword(s):  
Hydrogen Bonding ◽  
Coordination Polymers ◽  
3D Structure ◽  
Three Dimensional ◽  
Great Influence ◽  
Two Dimensional ◽  
3D Network ◽  
Solvent Molecules ◽  
Bonding Systems ◽  
Polymeric Structures

Three new one- (1D) and two-dimensional (2D) CuII coordination polymers, namely poly[[bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole}copper(II)] bis(methanesulfonate) tetrahydrate], {[Cu(C13H12N5S)2](CH3SO3)2·4H2O} n (1), catena-poly[[copper(II)-bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole}] dinitrate methanol disolvate], {[Cu(C13H12N5S)2](NO3)2·2CH3OH} n (2), and catena-poly[[copper(II)-bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole}] bis(perchlorate) monohydrate], {[Cu(C13H12N5S)2](ClO4)2·H2O} n (3), were obtained from 4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole with pyridin-3-yl terminal groups and from 4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole with pyridin-4-yl terminal groups. Compound 1 displays a 2D net-like structure. The 2D layers are further linked through hydrogen bonds between methanesulfonate anions and amino groups on the framework and guest H2O molecules in the lattice to form a three-dimensional (3D) structure. Compound 2 and 3 exhibit 1D chain structures, in which the complicated hydrogen-bonding interactions play an important role in the formation of the 3D network. These experimental results indicate that the coordination orientation of the heteroatoms on the ligands has a great influence on the polymeric structures. Moreover, the selection of different counter-anions, together with the inclusion of different guest solvent molecules, would also have a great effect on the hydrogen-bonding systems in the crystal structures.

Self-assembly of new three-dimensional molecular architectures of Cd(II) and Ag(I)–Na(I) using croconate as a building block

2002 ◽  
pp. 171-175 ◽  
Author(s):  
Tapas Kumar Maji ◽  
Sanjit Konar ◽  
Golam Mostafa ◽  
Ennio Zangrando ◽  
Tian-Huey Lu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Building Block ◽  
Three Dimensional ◽  
Molecular Architectures

The decomposition of methyl hemiacetals of benzaldehyde in aqueous solution: a study of the effect of aromatic substitution

1999 ◽  
Vol 77 (5-6) ◽  
pp. 978-989 ◽  
Author(s):  
Karen M Engell ◽  
Robert A McClelland ◽  
Poul E Sørensen
Keyword(s):  
Bond Cleavage ◽  
Heavy Atom ◽  
Three Dimensional ◽  
Interaction Coefficient ◽  
Base Catalysis ◽  
Aromatic Substitution ◽  
Acid Base ◽  
Rate Limiting Step ◽  
Acid And Base ◽  
Energy Contour

The acid-base catalysed decomposition of hydrates and hemiacetals of carbonyl compounds are classical examples of reactions where (slow) proton transfer is coupled with heavy atom reorganization, i.e., C—O bond breaking and solvent reorganization. We have studied the influence of m- and p-substitution in the carbonyl electrophile on the kinetics of the acid and base catalysis of the decomposition of methyl hemiacetals of benzaldehyde. The experimental data are well described by three-dimensional More O'Ferrall - Jencks energy contour diagrams according to principles developed by Jencks (the BEMA HAPOTHLE). Thus, for acid catalysis, a Cordes cross-interaction coefficient pxy' = δρ/δpKa = 0.15 indicates the coupled nature of the rate-limiting step in a class e mechanism, similar to conclusions reached from systematic substitution in the nucleophile. Our more extensive set of data for base catalysis permits a more rigorous analysis according to the BEMA HAPOTHLE. The data are consistent with a class n mechanism as also suggested earlier on the basis of substitution in the nucleophile. A slight upward curvature observed in the Hammett plots for the various catalysts is described by the direct correlation parameter py = -δρ/δσ = -0.11. This second derivative demonstrates the concerted nature of the C—O bond cleavage and O-H formation in the transition state, which changes with changing substituent. A class n mechanism for base catalysis is also supported by the observation of a Cordes cross-interaction parameter pxy = -δρ/δpKa = -δβ/δσ = 0.03, which describes the experimentally observed decrease in Hammett ρ with increasing pKa of the catalyst. This change may be rationalized by the movement of a saddle point on a diagonal reaction coordinate in the energy contour diagram, as a resultant of shifts parallel and perpendicular to the coordinate, when the energy along one side of the diagram is changed. It is concluded that observed rate changes as a result of substitution in the electrophile are consistent with and present further confirmation of earlier suggested mechanisms of hemiacetal decomposition reactions.Key words: methyl hemiacetals of benzaldehydes, acid-base catalysed breakdown, Hammett plots, More O'Ferrall - Jencks diagrams.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Nanoscale Self-Assembly Using Ion and Electron Beam Techniques: A Rapid Review

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho
Keyword(s):  
Electron Beam ◽  
Self Assembly ◽  
Ion Beam ◽  
Three Dimensional ◽  
The Self ◽  
Stress Generation ◽  
Rapid Review ◽  
High Yield ◽  
3D Nanostructures ◽  
Self Assembled

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

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