Self-assembled monolayers cyclodextrins

Fe2(III,III)2+ states. By considering that organometallic dendrimers based on conjugated ferrocene units are of special importance since mixed-valence states have interesting electrical, redox, and magnetic properties, recently three generations of polypropylene amine) dendrimers, decorated at their periphery with 4, 8, and 16 (compound 6, Fig. 6.6a) BFc units, respectively, have been synthesized and the electrochemical behavior of the dendrimers complexed with (3-cyclodextrins ([3-CD) and adsorbed at self-assembled monolayers (SAMs) of heptathioether-functionalized [3-CD on gold (molecular printboard) has been studied.40... 

Figure 6.12 The molecular capsule 6.33b-6.34 held by interactions to cyclodextrins as a self-assembled monolayer on gold. (Reproduced by permission of The Royal Society of Chemistry).

Instead of cyclodextrin, calixarene has also been used as the monolayerforming component in sensor preparation. In the example shown in Fig. 4.41, a self-assembled monolayer of calixarene was immobilized on an electrode of a quartz crystal microbalance. The quartz crystal microbalance is a masssensing device capable of nanogram-level precision (see Chap. 5). When the monolayer-covered microbalance was exposed to guest gas, the guest bonding... 

Y. Maeda, T. Fukuda, H. Yamamoto, H. Kitano, Regio- and Stereoselective Complex-ation by a Self-Assembled Monolayer of Thiolated Cyclodextrin on a Gold Electrode , Langmuir, 13,4187(1997)... 

Kitano, H. Taira, Y. Inclusion of bisphenols by a self-assembled monolayer of thiolated cyclodextrins on gold electrodes. Langmuir 2002, 18, 5835-5840. 

Electrochemical properties of polypyrrole films grown in LiC104 acetonitrile solution (2% water) at gold electrodes modified with thiolated /3-cyclodextrin self-assembled monolayers have been investigated. Scanning electron microscopic results show that thiolated /3-cyclodextrin acts as a molecular template to restrict the growth sites within the /3-cyclodextrin cavities (50). 

In this paper, a study of supramolecular host-guest interactions between small molecules is reported. Interactions between p-cyclodextrin (P-CD) receptors in highly ordered self-assembled monolayers (SAMs) on Au(lll) and ferrocene moieties immobilized on AFM tips were measured in dynamic force spectroscopy measurements [11]. 

With this feature in mind, numerous organized macromolec-ular architectures have been deposited on electrode surfaces. Accordingly, self-assembled monolayers [387] and Langmuir-Blodgett-type [388] multilayers have been used to attach numerous functional moieties to electrode surfaces, e.g., crown ethers [389-391] and other complexing macrocyclic cavities (cal-ixarene [392], cyclodextrin [393], and cyclophane [394-396]), vio-logens [397], porphyrins [398, 399], and enzymes [400-402]. 

An interesting example of a system whose components become mechanically bound upon surface immobilization is rotaxane trans-21 (Fig. 13.24), consisting of a ferrocene-functionalized /3-cyclodextrin (fi-CD) macrocycle threaded on a molecule containing a photoisomerizable azobenzene unity and a long alkyl chain.33 A monolayer of trans-21 was self-assembled on a gold electrode. Therefore, the ring... 

In order to improve synthesis of TM/3CDLA, the self-assembly of monolayers on a gold electrode based on a protected cyclodextrin-LA derivative, viz. mono-6-lipoyl-amido-2,3,6-0-peracetyl-)3-cyclodextrin, has also been performed involving the deacetylation step on the electrode surface after monolayer formation <2003ANC5687>. Applying the same methodology, immobilization of the /3-cyclodextrin-LA derivative, mono-6-deoxy-lipoyl-amido-per-2,3,6-0-acetyl-/3-cyclodextrin on the solid surface was employed for the preparation of cyclodextrin-modified gold electrodes. 

Yan and Dong found that -cyclodextrin forms inclusion complexes with linear alka-nethiols in bulk medium and thereby effects solubilization of alkanethiols in the aqueous solution of -cyclodextrin. Such complexes self-assemble on the gold surface to give stable monolayers . 4,4 -Bipyridinium (viologen) containing thiols also form inclusion complexes with cyclodextrins in bulk solution which can be used to prepare self-assembled... 

Callari F, Petraia S, Sortino S. 2006. Efighly photoresponsive monolayer protected gold clusters by self assembly of a cyclodextrin azobenzene derived supramolecular complex. Chem Commun 1009 1011. 

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