Tectons, self-assembly

Manna, J., C.J. Kuehl, J.A. Whiteford, P.J. Stang, D.C. Muddiman, SA. Hofstadler, and R.D. Smith (1997). Nanoscale tectonics Self-assembly, characterization, and chemistry of a novel class of organoplatinum square macrocycles. J. Am. Chem. Soc. 119, 11611-11619. 

Lehn has outlined a hierarchical order of the terms tern-plating, self-assembly, and self-organization to describe the spontaneous formation of supramolecular assemblies composed of preprogrammed molecular components (i.e., tectons) Self-assembly concerns the antientropic aggregation of individual components to yield an ordered multi-molecular entity. Intermolecnlar interactions that are intrinsically preprogrammed (see synthon) into the bnilding... 

The diaminopyridodipyrimidinedione 73 has been synthesised as a cytosine-like Tecton designed for self assembly into a helical superstructure. Self recognition occurs in the solid state <96MI02 96CA(125)221771 >. 

The layer thickness usually depends on the compounding module s size and an accurate metric engineering can be done according to which the length of starting module determines the thickness of the layer. This holds for self-assembled architectures wherein the XB acceptor is both an anionic [ 189] (Fig. 13) and a neutral tecton [168]. 

For instance, adamantanoid architectures are formed on the self-assembly of tetradentate XB donors with tetradentate XB acceptors, both the complementary tectons alternating at the nodes of the network (this is the case in the complex CBr4/Et4N+Cl and its bromide and iodide analogues [192], in the complex tetrakis(4-pyridyl)pentaerythritol/tetrakis(4-iodiotetralluorophenyl)pentaerythritol [195], and in other systems [197]). 

We saw in Figure 1.2c that supramolecular chemistry is not just about solid state or solution host-guest chemistry but increasingly emphasises self-assembly and the construction of multi-nanometre scale devices and ultimately materials based on nanometre-scale components (a nanometre is 10 9 of a metre). Strict supramolecular self-assembly (Chapter 10) involves the spontaneous formation of a multi-component aggregate under thermodynamically controlled conditions based on information encoded within the individual building blocks (referred to as tectons ) themselves. The aggregate might comprise only one kind of molecule (as in the multiple copies of the same protein that comprise... 

Hajek, F., Graf, E., Hosseini, M. W., Delaigue, X., DeCian, A., Fischer, J., Molecular tectonics. 1. The first synthesis and X-ray analysis of a linear koilate obtained by self-assembly of linear koilands and hexadiyne. Tetrahedron Lett. 1996, 37, 1401-1404. 

Self-assembly is the spontaneous and reversible association of molecules or ions (tectons) to form larger, more complex supramolecular entities according to the intrinsic information contained in the molecules themselves. 

Self-assembly of a single molecular component or molecular tectonics. 27 In such a situation, all the molecular recognition features that lead to supra-molecular synthons15d are present in a single molecule. 

Wuest has demonstrated that the pyridone moiety also generates a hydrogen-bonded supramolecular synthon that is suitable for building extended arrays.67 Remarkably, methanetetra(6-phenylethynyl-2-pyridone) exhibits a diamondoid network, sevenfold interpenetration and cavities large enough to enclathrate butyric or valeric acid.27 Wuest introduced the concept of tectons to describe molecules that inherently possess the molecular structure and intermolecular recognition features to predictably self-assemble into crystalline networks. He followed this study with several other examples of diamondoid networks sustained by the pyridone moiety 27c d... 

The self-assembly methodology can be extended to linkers containing oxygen. Oxalate 62 and oxocarbon dianions 63 and 64 are rigid molecules that react immediately with tecton 31 in water/acetone to form neutral metallomacro-cycles 65, 66, and 67, respectively, in 90-98% yields <2005IC7130>. 

The term synthon is more familiar to organic chemists and describes fragments from which varions molecnles can be bnilt by synthetic procedures. Sometimes the term was also used to describe structural units within supermolecules which can be formed and/or assembled by known or conceivable synthetic operations involving intermolecular interactions To avoid confusion, the term tecton was introduced to describe the molecular units of supramolecular structures assembled through noncovalent forces. Thus, the tecton has been defined as any molecule whose interactions are dominated by particular associative forces that induce self-assembly of an organized network Here, we will use the term synthon for... 

Treatment of 2,9-dibromophenanthrene with Pt (Et3P)4 followed by bromine-nitrate exchange gave the desired 60° tecton, 2,9-6/i [/ra 5 -Pt(PEt3)2(N03)]phenanthrene, which with different linear connectors afforded a series of self-assembled supramolecular triangles <03JA5193>. A series of related binuclear metallomacrocycles [Cd(N03)2L]2, where L is an angular exo-bidentate, such as 4-(4 -pyridinyl)(2-pyridinylethynyl) benzene, have been reported... 

Substituted anilines have found use in the synthesis of tectons for self-assembly studies in biological systems140. The diaminotriazine 193, a tecton, undergoes molecular self-assembly, offering potential for one-step syntheses of macromolecules (Scheme 37)141. A versatile tecton is 2-amino-4,6-dichlorotriazine (194)142. 

Self-assembling systems do not involve hosts and guests but rather self-complementary molecules or complementary partners (tectons). 

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