Ladder architecture

Baxter. P.N.W. Hanan, G.S. Lehn, J.-M. Inorganic arrays via multicomponent self-assembly The spontaneous generation of ladder architecture. Chem. Commun. 1996. 2019-2020. 

Fig. 11 Ladder-type architecture formed by self-assembly of a tridentate module (I ) with a bidentate module (1,4-DITFB)...

Concerning the nomenclature of higher-dimensionality silicon polymers such as networks, ladders, cages, and dendrimers, the variety of architectures possible is too great to treat concisely here, and the reader is directed to IUPAC sources.2... 

Metal-directed Self-assembly of Complex Supramolecular Architecture Chains, Racks, Ladders, Grids, Macrocycles, Cages, Nanotubes and Self-intertwining Strands (Helicates)... 

An alternative polymerization mechanism and polymer architecture has been proposed by Kirchhoff [1, 2, 3], Tan and Arnold [77], By this mechanism, polybenzocyclobutenes which do not contain reactive sites of unsaturation are proposed to polymerize by the 1,4 addition of the o-quinodimethane intermediates to give a substantially linear poly(o-xylylene) structure. Since the monomers all contain at least two benzocyclobutene units the net result of this reaction will to a first approximation be a ladder type polymer as shown in Fig. 17. The formation of a true ladder polymer however would require that all... 

Conceptually, the macromolecular architecture of polycatenanes 9 bears many similarities to that of ladder polymers 15, depicted in Scheme 5. Therefore, certain similarities also exist between synthetic strategies leading to both polycatenanes 9 and ladder polymers 15. Conceptually, two synthetic routes may be envi-... 

Figure 9.1 Schematic representation of some of the simple network architectures structurally characterised for metal-organic polymers (a) 2D honeycomb, (b) ID ladder, (c) 3D octahedral, (d) 3D hexagonal diamondoid, (e) 2D square grid, and (f) ID zigzag chain (reprinted from Section Key Reference The American Chemical Society).

Figure 7.6. Schematic illustration of the formation of a layered architecture from the edge-shared four-membered ladder structure.

Flexibility in ligands can lead to subtle or dramatic changes in architecture. For example, l,2-bis(pyridyl)ethane, dipy-Et, can readily adapt gauche or anti conformations. In the case of [Co(dipy-Et), 5(N03)2]n, which contains a T-shape node, infinite molecular ladders which contain six molecules of chloroform per cavity exist as the most commonly encountered architecture (Figure 3A).45b In such a situation all spacer ligands are necessarily anti. However, under certain crystal-... 

The bilayer architecture has been observed in at least three compounds.48 Interestingly, it has been observed as the product from the reaction of Co(N03)2 and bipy, which also generates ladder, square grid, and herringbone architectures. The bilayer form of [Co(bipy)j 5(N03)2] is observed if crystallization occurs in the presence of CS2 or H20. The bilayers pack by partial interdigitation, which allows... 

Among the inorganic open-framework compounds, the family of phosphates is a large one [3]. A large variety of open-framework metal phosphates of different architectures have been synthesized in the last few years. They include one-dimensional (ID) linear chain and ladder structures, two-dimensional (2D) layer structures and three-dimensional (3D) channel structures [4]. In the linear chain and ladder structures, four-membered metal phosphate units of the type M2P2O4 share comers and edges respectively. Zero-dimensional four-membered zinc phosphates have been synthesised and characterized recently [5]. Several open-framework metal carboxylates have also been reported [6] and the presence of a hierarchy of zinc oxalates covering the monomer, dimer, chain, honeycomb-layer and 3D structures has indeed been established [7]. 

Another important feature controlling the properties of polymeric systems is polymer architecture. Types of polymer architectures include linear, ring, star-branched, H-branched, comb, ladder, dendrimer, or randomly branched as sketched in Fig. 1.5. Random branching that leads to structures like Fig. 1.5(h) has particular industrial importance, for example in bottles and film for packaging. A high degree of crosslinking can lead to a macroscopic molecule, called a polymer network, sketched in Fig. 1.6. Randomly branched polymers and th formation of network polymers will be discussed in Chapter 6. The properties of networks that make them useful as soft solids (erasers, tires) will be discussed in Chapter 7. 

---