Porphyrin arrays connected with

Fig.26 a One-dimensional P(V)-porphyrin array connected with a conducting wire [78-80] b axial covalent attachment of a terpy-moiety that modulates the electronic properties of the array through additional metal complexation [M = Zn(II) or Cd(II)] [81]... 

Figure 47. Porphyrin assemblies. (A) Porphyrin monomer with two oligothiophene, (B) 1-D porphyrin arrays connected with molecular conjugated wires, (C) insulating wires and (D) 2-D porphyrin arrays connected with molecular conjugated wires. Reprinted with permission from Segawa, H. Nakayama, N. Shimidzu, T, /. Chem. Soc., Chem. Commun. 1992, 7B4.

Optical and Photonic Functions of Conjugated Polymer Superlattices and Porphyrin Arrays Connected with Molecular Wires... 

Conjugated polymer superlattices and porphyrin arrays connected with molecular wires are superstructured materials, which exhibit unique optical and photonic functions. The former shows a shift in photoluminescence to higher energy which is interpreted as a quantum size effect. The latter class of materials exhibits photoconductivity by a hole carrier mechanism and photoinformation storage by a localized excitation mechanism. The syntheses of these two classes of materials are described. 

Porphyrin Arrays Connected With Molecular Wires... 

ID porphyrin arrays connected with conjugating molecular wire... 

ID porphyrin array connected with insulating molecular wire 2D porphyrin array connected with conjugating molecular wire... 

Fig. 8 Singlet and triplet photoexcited states of 1-D porphyrin arrays connected with insulating molecular wires of short and long chains.

The present study on photoactive ID and 2D porphyrin arrays connected with molecular wires together with their syntheses open the way to 3 D porphyrin array which is expected to be a proto-type molecular device and an artificial photo-neuron. 

Both conjugated polymer superlattices and porphyrin arrays connected with molecular wires device which are described here represent powerful candidates for optical and photonic materials. 

Star-shaped multi-porphyrin arrays have been constructed to mimic energy funneUng in photosynthesis. These dendrimers contain free-base porphyrin cores (Pfb) connected to four dendrons consisting of 1,3, or 7 zinc-metallated porphyrins (Pzn) embedded in an organic matrix coimected by ether linkages (Scheme 21) [70,71]. The periphery consists of methoxy-terminated poly(aryl ether) dendrons. For comparison, cone-shaped arrays consisting of Pfb cores monosubstituted with Pz dendrons were also synthesized. 

Fig. 25). Alternatively, one can "reverse the process. Porphyrin array formation can start with imidazolyl zinc porphyrin, which can be immobilized using, for example, thiolate attachment on the electrode surface [90,91]. In this case the porphyrin attached to the electrode can serve as a molecular solder connecting the electrode to polymers made of hundreds of meso-meso-or bis(acetylene)-linked bis(imidazolyl zinc porphyrins) 55 [92]. Molecular wires or light-energy conversion systems could be built on the basis of such technologies. 

The synthesis was recently extended from grid porphyrin arrays to soluble windmill arrays [109]. Flanking with a peripheral Ni p-octaalkylporphyrin was achieved by Ag(I)-promoted coupling reactions of 1,4-phenylene-bridged linear porphyrin arrays, which are composed of a central Zn P-free porphyrin. Up to 48 porphyrin rings were connected. Efficient singlet energy transfer from the peripheral porphyrins to the central Zn-porphyrins was found. 

When electron transfer processes are targeted, one of two different options can be chosen. The first deals with photoinduced charge separation. This requires the connection of the photoactive unit, the porphyrin or muitiporphyrin architecture, to a nonporphyrinic eiectron donor and/or acceptor. The second option concerns electron conduction in muitiporphyrin arrays. The donor and acceptor in this case can be eiectrode materiais to which the array is connected on both sides. 

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