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Controlled Assembly (controlled + assembly)

Distribution by Scientific Domains
Chemistry50%

Selected Abstracts

Controlled Assembly of [Nb6,xWxO19](8,x), (x = 0,4) Lindqvist Ions with (Amine)copper Complexes

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2008
Travis M. Anderson
Abstract The mixed addenda isopolyanion, [N(CH3)4]2Na2[cis -Nb2W4O19]·18H2O, reacts with Cu(NO3)2 in water and in the presence of NH2CH2CH2NH2 (en) or NH4OH at 60 °C to yield a phase that is decorated {[Cu(en)2(H2O)]2[Nb2W4O19]·2H2O (1)} or charge-balanced {[Cu(NH3)4(H2O)]2[Nb2W4O19]·8H2O (2)}, respectively, by (amine)copper complexes. The prolonged heating at 95 °C of [N(CH3)4]6[Nb10O28]·6H2O, [N(CH3)4]2Na2[cis -Nb2W4O19]·18H2O, or Na4K2[cis -Nb4W2O19]·12H2O and Cu(NO3)2 in a mixed water/amine [en or NH2CH2CH2CH2NH2 (dap)] solution results in the formation of two-dimensional materials with alternate layers of (amine)copper complexes linking Lindqvist [Nb6,xWxO19](8,x), (x = 0,4) clusters. These phasesinclude: [Cu(dap)2]3[Nb4W2O19]·7H2O (3), [Cu(dap)2]3[H2Nb6O19]·6H2O (4), [Cu(dap)2]3[Nb3W3O19]·Cl·6H2O (5), and [Cu(en)2]3[Nb4W2O19]·6H2O (6). Complexes 4 and 5 result from the decomposition of [Nb10O28]6, and [cis -Nb2W4O19]4, to [H2Nb6O19]6, and [fac -Nb3W3O19]5,, respectively, in alkaline solution. Complex 5 contains an extra-framework site that is occupied by Cl,, but this site is occupied by a water molecule in 3 and is vacant in structures 4 and 6. The results of this study suggest that charge density, cluster charge and symmetry, and cluster-cation pairing are all important parameters in the incorporation of d-electron metals onto the surfaces of [Nb6,xWxO19](8,x), (x = 0,4) clusters or into the frameworks of Lindqvist-based complex materials.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

GaN Nanofibers based on Electrospinning: Facile Synthesis, Controlled Assembly, Precise Doping, and Application as High Performance UV Photodetector,

ADVANCED MATERIALS, Issue 2 2009
Hui Wu
Nitride nanofibers have been synthesized based on a simple electrospinning technique for the first time. No catalysts or templates are needed in this new synthetic method. Highly oriented GaN nanofiber arrays, as well as a high-performance UV photodetector based on single GaN nanofiber assembled FET devices, can be facilely fabricated using this technique. Precise doping of other elements into the GaN nanofibers is easy by this solution-based synthetic method. [source]

Controlled Assembly of Protein,Nanoparticle Composites through Protein Surface Recognition,

ADVANCED MATERIALS, Issue 5 2005
S. Srivastava
Controlled assembly of protein,nanoparticle composites through complementary protein surface recognition is demonstrated. Interaction of an unstable protein (chymotrypsin) with a gold nanoparticle results in close interparticle spacing, while a stable protein (cytochrome,C) that retains its structure upon binding produces a hybrid material with a larger interparticle distance (see Figure). [source]

Controlled Assembly of Au, Ag, and Pt Nanoparticles with Chitosan

CHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2009
Min Hong
Abstract Working on the chain gang: A simple method for the controlled assembly of metal nanoparticles (Au, Ag, and Pt) into 1D chains (see figure) has been developed based on the electrostatic interaction of negatively charged carboxylic groups on the citrate ions surrounding the NPs and the positively charged chitosan polymer. A simple method for the controlled assembly of metal nanoparticles into one-dimensional chains has been developed. The chain-formation process could be accounted for by the electrostatic interaction of the negatively charged carboxylic groups on the citrate ions surrounding metal nanoparticles and the positively charged chitosan polymer. Three representative types of nanoparticles comprising Au, Ag, and Pt, respectively, have been used to illustrate the generic applicability of the proposed methodology. Facile control of the chain length of the nanoparticle assembly could be achieved by adjusting the concentrations of negatively or positively charged species. We anticipate the ready adaptability of the methodology to nanoparticles of more complex compositions. [source]

Controlled Assembly of Protein,Nanoparticle Composites through Protein Surface Recognition,

ADVANCED MATERIALS, Issue 5 2005
S. Srivastava
Controlled assembly of protein,nanoparticle composites through complementary protein surface recognition is demonstrated. Interaction of an unstable protein (chymotrypsin) with a gold nanoparticle results in close interparticle spacing, while a stable protein (cytochrome,C) that retains its structure upon binding produces a hybrid material with a larger interparticle distance (see Figure). [source]

Controlled Assembly of Au, Ag, and Pt Nanoparticles with Chitosan

CHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2009
Min Hong
Abstract Working on the chain gang: A simple method for the controlled assembly of metal nanoparticles (Au, Ag, and Pt) into 1D chains (see figure) has been developed based on the electrostatic interaction of negatively charged carboxylic groups on the citrate ions surrounding the NPs and the positively charged chitosan polymer. A simple method for the controlled assembly of metal nanoparticles into one-dimensional chains has been developed. The chain-formation process could be accounted for by the electrostatic interaction of the negatively charged carboxylic groups on the citrate ions surrounding metal nanoparticles and the positively charged chitosan polymer. Three representative types of nanoparticles comprising Au, Ag, and Pt, respectively, have been used to illustrate the generic applicability of the proposed methodology. Facile control of the chain length of the nanoparticle assembly could be achieved by adjusting the concentrations of negatively or positively charged species. We anticipate the ready adaptability of the methodology to nanoparticles of more complex compositions. [source]