Stacked polymers

Fig. 30 Left Side view of a single chain of amphiphilic polymer 52 at the air-water interface. Right End-on view of three adjacent n-stacking polymer chains...

Fig. 12 a, b Electronic band structure of the rhombohedral C60 polymer with a ACB stacking and b ABC stacking, respectively. In each case, the electronic density of states is shown (in arbitrary units) energy is measured from the valence band top. The two systems show very similar valence-band dispersions, while the conduction-band states show a little difference in their dispersion. The fundamental gap of the ABC stacking polymer (lower panels) is found to be narrower than that of the ACB stacking polymer (upper panels) [39]... 

As important examples of square complexes, we may mention yellow [Ni(CN)4]2, red bis(dimethylglyoximato)nickel(II) (17-G-V), which gives a stacked polymer, and the yellow to orange-brown compounds NiX2(PR3)2 (R = alkyl or aryl). 

Type III The metal is part of a polymer chain or network. This type considers homochain or heterochain polymers with covalent bonds to the metal, coordinative bonds between metal ions and a polyfunctional ligand (coordination polymers), Ti-complexes in the main chain with a metal, cofacially stacked polymer metal complexes and different types (polycatenanes, polyrotaxanes, dendrimers with metals) (Figure 3). 

The thermal polycondensation of dihydroxy(metallo)phthalocyanines to cofacially stacked polymer in the solid state as example of a type III polymers [equation (7)] is topotactic and under topochemical control, which means that well-defined intermolecular distances and interactions in the lattice control the reaction [56]. Following a kinetic study the fraction of unreacted -OH end groups X over time does not obey a first order kinetics (X = exp(— 2 ), M = Si, Ge, Sn n = 50-200). 

The cofacial stacked polymers are characterized by different chemical stabilities. Whereas polymers 108 may be unaffected by aqueous HF at 100 °C, aqueous 2 M NaOH at reflux and concentrated H2SO4, polymers 110 are not stable and are reacting with an excess of a monofunctional and even a bifunctional donor ligand under heating. The thermal stability in general increases in the sequence 110 < 109 < 108. These polymers can exhibit very high electrical conductivities as compressed powders of 10 Scm [34,376]. 

K. Kato, K. Tanaka, S. Tsum, and S. Sakai, Multipage display using stacked polymer-dispersed liquid crystal films, Jprt J. Appl. Phys. 32, 4594-4599 (1993) ... 

Stacked phthalocyanine polymers (52) with oxygen bridges between the metal atoms have been prepared by dehydration of the phthalocyanine complexes of Si, Ge, and Sn to produce face-to-face stacking polymers." " When the oxygen-bridged systems are oxidatively doped, they become electrically conducting or semiconducting. 

The electrical, optical, and magnetic properties of stacked polymers are a delicate function of architectural and electronic control. For example, electrochemical oxidation in the presence of BF4 causes a change in structure from orthorhombic to tetragonal as the BF4" coimterions move into the closely packed sfructure (Fig. 1)." Moreover, the electrical properties are tunable. This was the first case where the band filling of a molecular metal was broadly tunable. 

Phthalocyanine complexes of Ge were prepared by Marks et al. and converted to stacked polymers imder dehydrative conditions. The degree of polymerization for... 

T. Nakano (ed.), n-Stacked Polymers and Molecules Theory, Synthesis, and Properties, DOI 10.1007/978-4-431-54129-5 l, Springer Japan 2014... 

Poly(DBF) is a vinyl polymer and is kin of polystyrene, a versatile and durable material unlike the other jc-stacked polymers. However, poly(DBF) and its derivatives have characteristic structural and functional features that are not known for polystyrene and its analogues and can be recognized, in the context of this chapter, as a polyethylene derivative which creates an ordered alignment of fluorene, a chro-mophore molecule. Hereafter, the synthesis, structure, and properties of ju-stacked poly(DBF) and its derivatives are described in detail. 

An alternative interpretation may be that the elecnonic interaction of the stacked fluorene groups in the polymer side chain extends inherently up to ca. five units even for a long, completely uniform frozen jt-stacked polymer. Absorption measurements at an extremely low temperature or in a solid-state matrix that may significantly retard molecular vibration might provide an answer. Computational studies on the electronic states of poly(DBF) may also be necessary. 

---