Tải bản đầy đủ - 0 (trang)
Hybrid (Nano)Materials Meet Supramolecular Chemistry: A Brief Introduction to Basic Terms and Concepts

Hybrid (Nano)Materials Meet Supramolecular Chemistry: A Brief Introduction to Basic Terms and Concepts

Tải bản đầy đủ - 0trang

2



Chapter 1 Hybrid (Nano)Materials Meet Supramolecular Chemistry



system often involves a phase in which the different researchers participating in such a

project have to settle terms and definitions and have to agree on a common “language,”

because similar terms or even identical abbreviations can have different meanings in

different scientific (sub)communities. For illustrative examples, one does not have to

embark on lengthy searches but can simply take a look at the List of Abbreviations of

this book. Attempting the unequivocal use of abbreviations book-wide, we were rather

soon confronted with the impossibility of doing so. Whereas for some abbreviations

used in various chapters with different meanings the unification was simple (e.g.,

MAA stood formerly for methacrylic acid and mercaptoacetic acid, the latter being

now abbreviated as TA for its synonym thioglycolic acid),Ã for others, it was not possible. In several cases, both abbreviations have become so common in different areas of

the chemical sciences, the natural sciences, or even society that we had to accept their

“schizophrenic nature” and kept them with two different meanings in the book.

Examples include

Fc

PL

PDA

CT

PC



ferrocene (or ferrocenyl)

photoluminescence

poly(diacetylene)

charge-transfer

photovoltaic cell



vs.

vs.

vs.

vs.

vs.



fragment, crystallizable (of an antibody)

phospholipid

personal digital assistant

computed tomography

personal computer



Therefore, the key features of supramolecular chemistry and nanomaterials important in the present context are introduced in the next two sections.



1.2 TERMS AND CONCEPTS IN SUPRAMOLECULAR

CHEMISTRY

Historically, the term supramolecular chemistry has been put onto the chemical map

by J.-M. Lehn in the middle of the 1980s,1 and received broad coverage from 1987 on,

the year Lehn, D. J. Cram and C. J. Pederson won the Nobel prize in chemistry.2–4 In

short, Lehn defined the term as the “chemistry of molecular assemblies and of the

molecular bond,” which is often used in its condensed form of the “chemistry

beyond the molecule.” According to Lehn, the main characteristics of a supramolecular ensemble are a certain degree of order and/or symmetry of the packing as well as an

interaction between the subunits and/or specific types of intermolecular interactions.

Since Lehn distinguishes between the supramolecular complex and the covalent molecule, these interactions are supposed to be noncovalent in nature. With regard to function or properties, supramolecular systems show certain abilities for recognition,

catalysis, and/or transport. In contrast, the covalent molecule has a unique chemical

nature, shape, and polarity (and chirality) as well as redox, optical, and/or magnetic

properties. In this sense, the covalent grafting of, for instance, a receptor unit onto a

silica nanoparticle does not create a supramolecular ensemble, but a hybrid material.

The latter nonetheless may exert a supramolecular function upon binding of a guest

(see, e.g., Chapter 11) or may provide a suitable platform to build a supramolecular

Ã

This is actually a more complicated case since the second most obvious abbreviation, TGA, also leads to a

conflict with a term widely used in the materials sciences, thermogravimetric analysis.



1.2 Terms and Concepts in Supramolecular Chemistry



3



ensemble (see, e.g., Chapter 13). The same holds for molecules attached to a metal

surface through bonds that have a pronounced covalent character, such as the gold –

thiol bond (see, e.g., Chapters 4 and 8). These hybrids are not supramolecular in

nature but composite or hybrid and can be used in a supramolecular context as discussed for instance in Chapters 15 and 23. In addition, complex molecules comprising

various active and/or addressable subunits in a covalent fashion such as for example

10 in Figure 17.9 in Chapter 17 are also not supramolecular ensembles, but the supramolecular function is only generated by using, in this case, the ferrocenyl-appended

cyclodextrin that interacts with different parts of switchable 10 through hydrophobic

forces, depending on the state the molecular machine is in.

Closely connected to the definition of Lehn is the term host – guest chemistry as

laid out by Cram.3 The same forces are at play and the main constraint with respect

to the more general concept of supramolecular chemistry pertains to the binding site

features that the two partners bring into the complex: whereas the guest can possess

divergent binding sites (extreme cases: spherical guests such as halide anions or metal

cations), the host has to be equipped with convergent binding sites (simple cases: a

crown ether as host for sodium ions5 or an oligopyrrole for the binding of chloride

ions).6 Very much related to host– guest complex formation is the term molecular

recognition, which implies that a certain receptor can discriminate between a

number of potential guests, that is, recognizes the designated guest.7 Historically,

all the concepts that are based on molecular specificity in binding are rooted in the biochemical background of the biological receptor8 and the principle of lock-and-key9

(initially coined for enzyme – substrate interactions; however, later modified for

these specific interactions to the principle of the induced fit).10 P. Ehrlich and J. N.

Langley developed the concept of the biological receptor from the observations

they made during their studies of how toxins and drugs can influence certain cellular

or synaptic functions (cited in Reference 8) and their dose-effect experiments foreshadowed analytical trends such as competitive assays or displacement assays, the

latter for instance being discussed here in Chapter 19. Regarding host – guest chemistry and molecular recognition, at the opposite end of the scale of complexity of

hosts such as crown ethers and oligopyrroles thus lie antibodies11,12 or their synthetic

analogs, molecularly imprinted polymers.13,14 The latter are featured in this book in

their organic – inorganic hybrid form in Chapter 20.

A typical feature of larger and more complex hosts is that they usually bind the

guest through multiple interactions in which the binding sites act in a concerted

fashion, that is, the overall binding constant between host and designated guest is

often the sum or even larger than the sum of the binding constants of the individual

binding sites with the guest. Such cooperative effects are also found in simple systems,

for example, for crown ethers or ethylenediamine tetraacetic acid (EDTA) and metal

ions, and are termed here macrocyclic effect15 or chelate effect.†16 To be able to





Note that in analogy to cofactors and substrates in enzyme chemistry, the general definition of cooperativity

usually concerns two different binding sites for two different guests and includes positive as well as

negative cooperativity: Cooperativity results when occupation of a given binding site leads to a change on

the binding features of the other site(s), making binding either easier or more difficult [J. M. Lehn,

Supramolecular Chemistry (Weinheim: VCH, 1995), 141 ff].



4



Chapter 1 Hybrid (Nano)Materials Meet Supramolecular Chemistry



bind a certain guest selectively, not only does the host have to possess the adequate

binding sites, but the latter have to be arranged in an optimal fashion. This means

that in supramolecular systems, preorganization often plays a critical role. Within

the context of this book, preorganization plays an outstanding role because the use

of inorganic, nanoscopically sized, structured or textured supports to preorganize

(bio)organic functionalities in such a way that they can be used in supramolecular recognition or signalling is one of the main driving forces in the field of hybrid materials

design (see, e.g., Chapter 14). Ultimately, the preorganization of the binding sites of

the host leads to a complementarity of host and guest that entails the unique response.

Having introduced the major principles of complexation, association, and organization, it is important to review the physicochemical forces that lead to supramolecular ensemble formation. As mentioned above, supramolecular interactions are by

definition noncovalent. In the order of the polarity of the partners involved, they comprise ionic or electrostatic interactions,17,18 ion – dipole interactions,19 dipole – dipole

interactions,20 (ionic) hydrogen bonding,21–23 cation-p 24 and anion-p interactions,25

p-p stacking,26 interactions based on van der Waals forces27 and hydrophobic effects,28

that is, the specific exclusion of polar solvents, in particular water, with specific packing effects in the solid state taking a special position.29 Whereas polar and electrostatic

forces are the key players to hold together tightly the porous coordination polymers

discussed in Chapter 7, van der Waals forces and solvent exclusion effects are decisive

forces in porous hybrid materials that mimic biological receptors like binding pockets

of proteins (see, e.g., Chapter 19). Because of the special physical parameters

involved, a delicate balance of (very) polar and (very) apolar interactions usually governs the possibilities of self-assembly at interfaces and the behavior of objects such as

self-assembled monolayers (SAMs)30 or Langmuir – Blodgett films (LB films).31

In terms of the physicochemical control of the selectivity in supramolecular systems, both thermodynamic and kinetic gain are important. Thermodynamic aspects

most of all govern a steady-state discrimination between different guests, the best

known examples being perhaps the binding of molecular oxygen to hemoglobin in

the presence of a number of potentially competing species such as molecular nitrogen,

water, and carbon dioxide, partly being present in rather high excess.32 Kinetic driving

forces are more important in catalytically acting systems such as enzymes since here

often the binding of the designated target is comparatively weak, yet the kinetics of

turnover for the guest of choice are much faster than for other potential guests as

well as for the same reaction in liquid solution.33 The loose binding is important

because the educt and the product of the catalytic reaction commonly have different

shapes, topologies, and chemical structures and the host has to rearrange during the

reaction. If enzymes would be preorganized in a rigid way to achieve stronger binding

of the (educt) guest, the reaction would be unfavorable.

Having mentioned self-assembled objects as examples already above in the context of supramolecular forces, this paragraph briefly introduces self-assembly34 and

templating or the template effect,35 both concepts being deeply rooted in supramolecular chemistry. While the term self-assembly relates to a system that performs spontaneously several steps in a single operation to create a supramolecular ensemble, the

DNA double helix being perhaps the most prominent biochemical example, templating



1.3 Terms and Concepts Relating to Nanomaterials



5



or template-directed synthesis requires a certain, temporary or permanent, species that

aids the conversion of reactants into a product through the formation of a supramolecular complex, for example, an alkali metal ion that promotes oxacrown synthesis.36

Besides objects such as molecular rectangles,37 capsules38 or rosettes,39 self-assembly

also includes mechanically interlocked architectures such as catenanes and rotaxanes,40 extremely relevant in the framework of hybrid molecular machines (see

Chapter 17), as well as coordination polymers (see Chapter 7). On the other hand,

recent advancements in the supramolecular chemistry of interfaces have propelled

the typical design of functional monolayers to another level of sophistication, allowing

the construction of programmed 3D architectures through layer-by-layer (LbL) assembly techniques.41 Several chapters in this book discuss the many facets related to

layered assembly in detail, including Chapter 2. In addition, micelles, liposomes,

and vesicles can be considered as dynamic supramolecular assemblies and gained

paramount importance in the biological context of the protocell.42,43 Finally, besides

the role of templates in synthesis, templating of course is intrinsically connected to

molecular imprinting and its use in chemical sensing.13,14



1.3 TERMS AND CONCEPTS RELATING TO

NANOMATERIALS

As fuzzy and buzzwordy as the words may sound, nanomaterials, nanochemistry, and

nanotechnology, including their nanobiological variations, form the cornerstones of

the research map that spans the size range between 1 nm and 1 mm.44,45 In view of

traditional chemistry, 1 nm is considered as being large, whereas the traditional engineer or physicist who was educated in the area of microtechnology regards 1 mm as

small;46,47 the interface is the main playground of the nanosciences. In particular, the

term nanomaterials encompasses inorganic, (bio)organic, or hybrid objects of nanometric size and bulk material that is structured or patterned at nanometric dimensions.

Typical terms of classification include dimensionally rather constrained objects such

as nanoparticles, nanocrystals, and nanotubes,48 dimensionally less defined objects

such as nanolayers and nanofibers, and nanosized voids like nanopores or nanocavities. Some classes can be subdivided into certain categories such as, for instance,

nanoparticles into nanospheres, nanorods,49 or nanocubes.50 It is interesting to note

that the term nanoparticle,51–53 even in a classic supramolecular sense, that is, as colloidal drug delivery system, was established in the pharmaceutical community even a

decade before the term nanotechnology saw a first significant increase in published

papers in the late 1980s, after the release of Drexler’s visionary book in 1986.‡45

Moreover, the functionalization of nanoparticles with complex hosts such as antibodies was also already realized before all the influential treatises on nanotechnology

appeared.54 Returning once more to the triangle of nanomaterials, nanochemistry, and



Colloidal metal nanoparticles, however, have been known for centuries since gold and silver nanoparticles

are responsible for the brilliant reds and yellows seen in stained glass windows. Scientific research on

metal nanoparticles dates back at least to M. Faraday; see, for example, M. Faraday, Philos. Trans. 1857,

147, 145– 181.



6



Chapter 1 Hybrid (Nano)Materials Meet Supramolecular Chemistry



nanotechnology, today, nanomedicine most likely constitutes the fourth cornerstone

and is perhaps the fastest developing one of the nano-areas, which was foreseen in

the late 1980s55 and closes the loop to the early development of nanoparticles in

the pharmaceutical sciences.

Among the nanoscopic objects, terms such as tubes, spheres, rods, and cubes are

self-explanatory and, as described in many chapters of the book, have today been

obtained from many different materials, including carbon, silica, or metals; see, for

example, Chapters 3, 4, and 6. These objects are commonly characterized by sizes

in the lower nanometer regime. Nanofibers, which can easily cross the border to

micrometer-sized objects, can have very diverse features, not only in size but also

in composition, ranging from pure carbon materials (e.g., graphitic fibers)56 via polymer assemblies57 to metal oxide fibers.58 Regarding topology, the term nanowire is

almost synonymous, yet it is basically used in connection with either metallic or semiconductor materials,59,60 which can, however, be also assembled by supramolecular

templating,61 or for molecular wires. Traditionally, molecular wires are conjugated

polymers designed for molecular electronics,62 yet they can be equipped with adequate groups to perform tasks of molecular recognition and act as sensory devices63

or they can show certain features that can only be obtained through the help of supramolecular forces, for example, in the case of insulated wires.64 The term nanocrystal,

on the other hand, is commonly used for typically small (mostly ,10 nm) particles

of inorganic origin, containing two different types of atoms such as CdSe, PbS,

or TiO2.65 They possess special properties arising from confinement effects, that is,

in these nanoscale objects the movement of an electron is confined in all three dimensions. The electrons can thus only populate discrete energy levels. Accordingly,

energy bands (e.g., of the bulk semiconductor) converge to discrete, atom-like states,

with the oscillator strength being compressed into few transitions, leading to the typically observed high absorption coefficients.66 Since in semiconductors the electronic

properties are strongly governed by the transitions between the edges of valence and

conduction band, confinement effects are more dramatic for these materials than for

metals (see, e.g., Chapters 5 and 10). When metallic materials are concerned which

are typically obtained by the reduction of a metal salt dissolved in an organic liquid,

producing also dimensionally small particles (mostly ,10 nm), these are mainly

referred to as (atomic) clusters.67 Inherent to both types of particles is the fact that

they are not very stable or soluble in neat form and usually carry a protective organic

shell, tightly adsorbed to the inorganic core. In the case of metal particles, particles

stabilized with an organic layer are frequently referred to as monolayer-protected

clusters.68 Because surface defects (dangling orbitals or dangling bonds) govern

especially the luminescence properties of semiconductor nanocrystals, such a capping

layer also determines the performance of these particles in desired applications (see,

e.g., Chapter 12). Besides organic ligands, the passivation procedure for semiconductor nanocrystals often comprises the growth of a second semiconductor layer onto the

core in a core-shell type of fashion (e.g., ZnS@CdSe) with subsequent capping with

organic ligands.69 In contrast to nanocrystals, the term nanocrystalline is often used

with a different connotation. These materials do not have to have nanoscale size,

but are usually composed of nanosized crystals or crystallites in a consolidated



1.3 Terms and Concepts Relating to Nanomaterials



7



state, the single crystallites being held together by interatomic forces acting between

the atoms in the crystals on either side of the defect core or defect site.70 In other

words, these materials consist of numerous defect cores that are embedded into (an

elastically distorted) crystal lattice(s). Since atoms at these defect sites possess unique

properties, the bulk material retains these properties in its entirety and not only at its

surface. Such materials are commonly produced by vapor deposition techniques,

the most prominent example today being perhaps nanocrystalline silicon, which consists of crystalline grains of approximately 10 to 1000 nm size. Nanolayer finally is a

very general term and is today used mainly in conjunction with composite materials

prepared by deposition techniques. The prefix nano relates here basically to the thickness or the structured pattern of the layer.

Talking about fabrication techniques, they fall basically in one of the two concepts

of nanotechnology, top-down and bottom-up.44 Top-down is the classic engineering

approach,71 while bottom-up relates to (bio)chemical synthesis.72 With respect to

discrete nanomaterial objects, carbon nanotubes isolated from soot on one hand and

silica materials synthesized through the sol – gel route or metal clusters through redox

reactions on the other hand can be seen as the two antipoles. The chemical bottom-up

strategies are intrinsically connected to supramolecular synthetic concepts, discussed

above. The top-down approaches important within the present context include various

deposition techniques for layered objects such as physical73 or chemical vapor deposition74 and, to a lesser extent, epitaxy techniques such as molecular beam epitaxy;75

the latter are much more frequently used in device construction, for instance in optoelectronics. Particles can be generated either by synthetic reduction (e.g., metal

particles), precipitation (e.g., semiconductor nanocrystals), and condensation techniques (e.g., using the sol – gel route), constituting the major routes, as well as by electrochemical deposition (e.g., for modified electrodes, see Chapter 9) or by physical

methods such as grinding or ball-milling (e.g., for polymer-nanoparticle hybrids),76

laser ablation (e.g., for Raman-active hybrid nanoparticles)77 and thermal decomposition.78 In addition, nanostructuring techniques comprise first of all lithographic

methods. For inorganic or rigid organic (e.g., polymer) supports, photolithography

is mostly used,79 other lithographic techniques such as electron beam lithography80

playing a minor role. Major advances in the field discussed in this book, however,

rely on the development of soft lithography for the attachment and patterning of

organic entities onto substrates,81 rendering the preparation of nanoarrays possible.82

Relatively straightforward is the definition of nanoscopic voids. Nanopores and

nanocavities are elongated voids or voids of any shape, and nanomaterials can incorporate especially nanopores in an ordered or disordered way. The former is of crucial

importance for many of the hybrid materials discussed in the book (e.g., in Chapters

16 or 18). Nanochannel is also frequently used instead of nanopore, often in biological or biochemical contexts. Besides nanoporous, the term mesoporous is often found

in hybrid materials research. Interestingly, the IUPAC has defined the terms mesoporous (pores with diameters between 2 and 50 nm), microporous (pores with diameters ,2 nm) and macroporous (pores with diameters .50 nm), yet has not given

a definition of nanoporous in the IUPAC Recommendations on the “Nomenclature

of Structural and Compositional Characteristics of Ordered Microporous and



8



Chapter 1 Hybrid (Nano)Materials Meet Supramolecular Chemistry



Mesoporous Materials with Inorganic Hosts.”83 Nanoscopic voids surrounded only by

a comparatively thin layer of hybrid material are often referred to as nanocontainers.

Intensive research on these hybrid analogs of micelles or vesicles has already accomplished rather sophisticated functions as presented in Chapter 22.

The last paragraph in the nano-section lists some terms that are frequently used in

connection with “nanoscience,” that are, however, rather ill- or very broadly defined

only. Among these, nanocomposite, nanodevice, nanosystem, and nanodomain are

perhaps the least specific ones because they concern any kind of composite material,

device, system, or domain that is related to nanometric dimensions. Nanofluidics,

nanoelectronics, nanolithography, and other such linguistic “nanocomposites”

encompass broad definitions, yet are self-explanatory, because they are rooted in the

parent, macroscopic technique. With respect to alluding research accomplishments

in nanochemistry or nanophysics to applications of the macroscopic world, a whole

new list of terms can easily be compiled from browsing (scientific) journals. People

publishing in or writing about nanomaterials and nanotechnology often tend to

illustrate their findings with more tangible terms such as nanoshells, nanotweezers,

nanoreactors, nanorobots, or nanofabrication.84



1.4



HYBRIDS



Finally, the term hybrid is not intrinsically connected to supramolecular chemistry or

nanomaterials but is commonly used for any combination of materials that can be

classified into the various subdisciplines of the chemical sciences. As the title of

the book suggests, most important here are organic – inorganic hybrids, stretching

into the fields of biomolecular – inorganic85 and polymeric – inorganic86 materials

such as those discussed, for example, in Chapter 21. Other combinations such as

biomolecular –polymeric, organic – biomolecular, or inorganic– inorganic hybrids

(e.g., alloy nanoparticles or AuNPs on supports consisting of other metals) are of

course also possible but have less relevance in the present context. The noun or

adverb composite is often used synonymously. In the scientific literature, the

term organic –inorganic hybrid material was first used by G. L. Wilkes’ group in

the context of organically modified silica materials prepared by the sol – gel route.87



REFERENCES

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.



J.-M. LEHN, Science 1985, 227, 849–856.

J.-M. LEHN, Angew. Chem. Int. Ed. Engl. 1998, 27, 89–112.

D. J. CRAM, Angew. Chem. Int. Ed. Engl. 1998, 27, 1009– 1020.

C. J. PEDERSEN, Angew. Chem. Int. Ed. Engl. 1998, 27, 1021– 1027.

S. MALEKNIA, J. BRODBELT, J. Am. Chem. Soc. 1992, 114, 4295– 4298.

J. L. SESSLER, D. AN, W.-S. CHO, V. LYNCH, M. MARQUEZ, Chem. Commun. 2005, 540–542.

J.-M. LEHN, Struct. Bonding 1973, 16, 1 –69.

M. R. BENNETT, Neuropharmacology 2000, 39, 523–546.

E. FISCHER, Ber. Dtsch. Chem. Ges. 1894, 27, 2985–2993.

D. E. KOSHLAND, Proc. Natl. Acad. Sci. U.S.A. 1958, 44, 98–104.



References

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

52.

53.

54.

55.

56.



9



C. MILSTEIN, Proc. R. Soc. Lond. Ser. B Biol. Sci. 1990, 239, 1– 16.

P. J. HUDSON, Curr. Opin. Biotechnol. 1998, 9, 395 –402.

K. HAUPT, K. MOSBACH, Chem. Rev. 2000, 100, 2495–2504.

G. WULFF, Chem. Rev. 2002, 102, 1 –27.

D. K. CABBINES, D. W. MARGERUM, J. Am. Chem. Soc. 1969, 91, 6540– 6541.

G. SCHWARZENBACH, Helv. Chim. Acta 1952, 35, 2344– 2363.

G. V. OSHOVSKY, D. N. REINHOUDT, W. VERBOOM, Angew. Chem. Int. Ed. 2007, 46, 2366– 2393.

R. C. AHUJA, P. L. CARUSO, D. MOăBIUS, G. WILDBURG, H. RINGSDORF, D. PHILP, J. A. PREECE,

J. F. STODDART, Langmuir 1993, 9, 1534–1544.

P. CINTAS, J. Inclusion Phenom. Mol. Recognit. Chem. 1994, 17, 205– 220.

C. HILGER, M. DRAEGER, R. STADLER, Macromolecules 1992, 25, 2498–2501.

D. C. SHERRINGTON, K. A. TASKINEN, Chem. Soc. Rev. 2001, 30, 83– 93.

M. MEOT-NER, Chem. Rev. 2005, 105, 213 –284.

T. STEINER, Angew. Chem. Int. Ed. 2002, 41, 48– 76.

J. C. MA, D. A. DOUGHERTY, Chem. Rev. 1997, 97, 1303–1324.

B. L. SCHOTTEL, H. T. CHIFOTIDES, K. R. DUNBAR, Chem. Soc. Rev. 2008, 37, 68–83.

C. A. HUNTER, J. K. M. SANDERS, J. Am. Chem. Soc. 1990, 112, 5525– 5534.

H.-J. SCHNEIDER, T. SCHIESTEL, P. ZIMMERMANN, J. Am. Chem. Soc. 1992, 114, 7698–7703.

D. B. SMITHRUD, E. M. SANFORD, I. CHAO, S. B. FERGUSON, D. R. CARCANAGUE, J. D. EVANSECK,

K. N. HOUK, F. DIEDERICH, Pure Appl. Chem. 1990, 62, 2227– 2236.

U. ZIENER, E. BREUNING, J.-M. LEHN, E. WEGELIUS, K. RISSANEN, G. BAUM, D. FENSKE, G. VAUGHAN,

Chem. Eur. J. 2000, 6, 4132–4139.

F. SCHREIBER, J. Phys. Condens. Matter 2004, 16, R881– R900.

J. A. ZASADZINSKI, R. VISWANATHAN, L. MADSEN, J. GARNAES, D. K. SCHWARTZ, Science 1994, 263,

1726– 1733.

M. C. MARDEN, L. KIGER, C. POYART, S. J. EDELSTEIN, Cell. Mol. Life Sci. 1998, 54, 1365– 1384.

J. J. PERONA, C. S. CRAIK, Protein Sci. 1995, 4, 337– 360.

D. PHILP, J. F. STODDART, Angew. Chem. Int. Ed. Engl. 1996, 35, 1155–1196.

S. ANDERSON, H. L. ANDERSON, J. K. M. SANDERS, Acc. Chem. Res. 1993, 26, 469– 475.

B. R. BOWSHER, A. J. REST, J. Chem. Soc. Dalton Trans. 1981, 1157– 1161.

P. THANASEKARAN, R. T. LIAO, Y. H. LIU, T. RAJENDRAN, S. RAJAGOPAL, K. L. LU, Coord. Chem. Rev.

2005, 249, 1085–1110.

M. M. CONN, J. REBEK, JR., Chem. Rev. 1997, 97, 1647– 1668.

G. M. WHITESIDES, E. E. SIMANEK, J. P. MATHIAS, C. T. SETO, D. N. CHIN, M. MAMMEN, D. M. GORDON,

Acc. Chem. Res. 1995, 28, 37– 44.

F. M. RAYMO, J. F. STODDART, Chem. Rev. 1999, 99, 1643–1663.

K. ARIGA, J. P. HILL, Q. JI, Phys. Chem. Chem. Phys. 2007, 9, 2319–2340.

P. L. LUISI, F. FERRI, P. STANO, Naturwissenschaften 2006, 93, 1–13.

S. MANN, Angew. Chem. Int. Ed. 2008, 47, 5306– 5320.

G. A. OZIN, Adv. Mater. 1992, 4, 612– 649.

K. E. DREXLER, Engines of Creation, New York: Anchor Books/Doubleday, 1986; electronic version:

http://e-drexler.com/p/06/00/EOC_Cover.html.

G. M. WHITESIDES, J. P. MATHIAS, C. T. SETO, Science 1991, 254, 1312–1319.

H. ROHRER, Microelectron. Eng. 1996, 32, 5 –14.

S. IIJIMA, Nature 1991, 354, 56–58.

H. DAI, E. W. WONG, Y.-Z. LU, S. FAN, C. M. LIEBER, Nature 1995, 375, 769– 772.

C. J. MURPHY, Science 2002, 298, 2139– 2140.

J. J. MARTY, R. C. OPPENHEIM, P. SPEISER, Pharm. Acta Helv. 1978, 53, 17–23.

J. KREUTER, Pharm. Acta Helv. 1978, 53, 33– 39.

R. C. OPPENHEIM, Int. J. Pharm. 1981, 8, 217– 234.

L. ILLUM, P. D. E. JONES, J. KREUTER, R. W. BALDWIN, S. S. DAVIS, Int. J. Pharm. 1983, 17, 65–76.

P. A. HANSSON, Futures 1991, 23, 849– 859.

N. M. RODRI´GUEZ, A. CHAMBERS, R. T. K. BAKER, Langmuir 1995, 11, 3862–3866.



10



Chapter 1 Hybrid (Nano)Materials Meet Supramolecular Chemistry



57. K. JAYARAMAN, M. KOTAKI, Y. ZHANG, X. MO, S. RAMAKRISHNA, J. Nanosci. Nanotechnol. 2004, 4,

52–65.

58. M. MACIAS, A. CHACKO, J. P. FERRARIS, K. J. BALKUS, Microporous Mesoporous Mater. 2005, 86, 1–13.

59. T. R. KLINE, M. TIAN, J. WANG, A. SEN, M. W. H. CHAN, T. E. MALLOUK, Inorg. Chem. 2006, 45,

7555– 7565.

60. H. J. FAN, P. WERNER, M. ZACHARIAS, Small 2006, 2, 700– 717.

61. E. GAZIT, FEBS J. 2007, 274, 317–322.

62. J. M. TOUR, Acc. Chem. Res. 2000, 33, 791–804.

63. T. M. SWAGER, Acc. Chem. Res. 1998, 31, 201–207.

64. M. J. FRAMPTON, H. L. ANDERSON, Angew. Chem. Int. Ed. 2007, 46, 1028– 1064.

65. Y. YIN, A. P. ALIVISATOS, Nature 2005, 437, 664– 670.

66. M. G. BAWENDI, M. L. STEIGERWALD, L. E. BRUS, Annu. Rev. Phys. Chem. 1990, 41, 477–496.

67. J. P. WILCOXON, B. L. ABRAMS, Chem. Soc. Rev. 2006, 35, 1162– 1194.

68. A. C. TEMPLETON, W. P. WUELFING, R. W. MURRAY, Acc. Chem. Res. 2000, 33, 27–36.

69. S. POKRANT, K. B. WHALEY, Eur. Phys. J. D 1999, 6, 255–267.

70. H. GLEITER, Adv. Mater. 1992, 4, 474– 481.

71. R. P. FEYNMAN, Eng. Sci. 1960, 23, 22–26, 30, 34, and 36, accessible online at http://www.zyvex.com/

nanotech/feynman.html.

72. J.-M. LEHN, Supramolecular Chemistry: Concepts and Perspectives, Weinheim: VCH, 1995.

73. K. REICHELT, X. JIANG, Thin Solid Films 1990, 191, 91– 126.

74. B. D. FAHLMAN, Curr. Org. Chem. 2006, 10, 1021–1033.

75. K. PLOOG, Angew. Chem. Int. Ed. Engl. 1988, 27, 593– 621.

76. M. XIONG, M. WU, S. ZHOU, B. YOU, Polym. Int. 2002, 51, 693– 698.

77. K. SISKOVA, B. VLCKOVA, P. Y. TURPIN, A. THOREL, A. GROSJEAN, Vib. Spectrosc. 2008, 48, 44– 52.

78. M. NAKADE, K. ICHIHASHI, M. OGAWA, J. Porous Mat. 2005, 12, 79– 85.

79. M. QHOBOSHEANE, P. ZHANG, W. H. TAN, J. Nanosci. Nanotechnol. 2004, 4, 635 –640.

80. J. JOO, S. MOON, J. M. JACOBSON, J. Vac. Sci. Technol. B 2006, 24, 3205– 3208.

81. Y. XIA, G. M. WHITESIDES, Annu. Rev. Mater. Sci. 1998, 28, 153– 184.

82. J. GU, X. XIAOIAO, B. R. TAKULAPALLI, M. E. MORRISON, P. ZHANG, F. ZENHAUSERN, J. Vac. Sci. Technol. B

2008, 26, 1860–1865.

83. L. B. MCCUSKER, F. LIEBAU, G. ENGELHARDT, Pure Appl. Chem. 2001, 73, 381–394.

84. S. A. EDWARDS, The Nanotech Pioneers, Weinheim: Wiley-VCH, 2006, 2 –3.

85. E. KATZ, I. WILLNER, Angew. Chem. Int. Ed. 2004, 43, 6042–6108.

86. H.-T. CHEN, Y. OFIR, V. M. ROTELLO in Molecular Recognition and Polymers (Eds. V. M. Rotello,

S. Thayumanavan), Hoboken, NY: Wiley, 2008, 137–157.

87. B. WANG, G. L. WILKES, J. C. HEDRICK, S. C. LIPTAK, J. E. MCGRATH, Macromolecules 1991, 24,

3449– 3450.



Chapter



2



Supramolecular Chemistry at

the Mesoscale

KATSUHIKO ARIGA, GARY J. RICHARDS,

JONATHAN P. HILL, AJAYAN VINU, AND

TOSHIYUKI MORI

2.1 INTRODUCTION



11



2.2 SUPRAMOLECULAR CHEMISTRY IN MESOSCOPIC MEDIA



12



2.3 SUPRAMOLECULAR ASSEMBLY AT THE MESOSCALE



18



2.4 SUPRAMOLECULAR MATERIALS AT THE MESOSCALE



25



2.5 FUTURE PERSPECTIVES



32



ACKNOWLEDGMENT



33



REFERENCES



33



2.1



INTRODUCTION



Dimensions between the atomic/molecular and the bulk macroscopic scales are

sometimes called “mesoscopic.” Because the mesoscopic scale corresponds roughly

to the electron free path, unusual phenomena such as quantum effects can be observed,

some of which could be used in the development of single-electron devices or

quantum computers. Top-down-type nanofabrication techniques are now capable of

producing structures in this size range, and research on this subject has received

significant attention, especially in the field of semiconductor science and technology.

The mesoscopic size regime is also relevant to organic chemistry and biochemistry since many biological mechanisms, including information transmission across cell

membranes, ribosomal protein synthesis, mitochondrial energy conversion, and enzymatic reactions, occur within complexes at the mesoscopic level. For construction of

functional mesoscopic structures from organic and biological components, bottom-up

The Supramolecular Chemistry of Organic–Inorganic Hybrid Materials. Edited by Knut Rurack and

Ramo´n Martı´nez-Ma´n˜ez

Copyright # 2010 John Wiley & Sons, Inc.



11



12



Chapter 2 Supramolecular Chemistry at the Mesoscale



Figure 2.1 Schematic illustration of the bottom-up approach from molecular to bulk scales.



approaches based on supramolecular self-assembly techniques have to be utilized,

because such structures require sophisticated arrangement of their components in order

to express fine functions. However, although formation of self-assembling structures

at the molecular- and nano-scales is well developed, fabrication of well-organized

structures in the mesoscale range remains a challenging target.1

In Figure 2.1, schematic representations illustrate strategies for creation of bulk

materials using molecular scale interactions through bottom-up supramolecular

approaches. Control of molecular arrangement,2–6 self-assembly or designed assembly processes,7–9 and structural transcription to materials10,11 all play important roles.

Additionally, construction of mesoscopic structures is one of the most important steps.

Assembly processes involving only organic materials are sometimes not suitable for

obtaining well-structured materials at the mesoscopic level. Combination of organic

or biological moieties with inorganic materials is one of the practical solutions to this

problem because inorganic materials can improve stability of the resulting hybrids.

Fabrication of organic– inorganic hybrid materials is thus an excellent route for the

construction of mechanically stable mesoscopic structures. Immobilization of organic

and biological components on inorganic supports leads to sophisticated arrangements

of these functional components, while transcription of supramolecular self-assembled

structures into inorganic materials results in novel functional inorganic structures.

These ambitious challenges can now be achieved at the mesoscopic scale.

In this chapter, supramolecular chemistry related to developments in materials

fabrication and functionalization at the mesoscale are discussed, with an emphasis on

those systems based on organic – inorganic hybrid structures. The contents of this

chapter are classified into (1) supramolecular chemistry within mesoscopic media,

(2) supramolecular assembly at the mesoscale, and (3) supramolecular materials at

the mesoscale. Despite this classification these topics have considerable similarities.



2.2 SUPRAMOLECULAR CHEMISTRY IN

MESOSCOPIC MEDIA

Molecular recognition is a key event in supramolecular chemistry since it determines

how molecules assemble in a predesignated way. Most molecular recognition events in



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Hybrid (Nano)Materials Meet Supramolecular Chemistry: A Brief Introduction to Basic Terms and Concepts

Tải bản đầy đủ ngay(0 tr)

×