Multiporphyrin assemblies

Hubberstey P, Suksangpanya U (2004) Hydrogen-Bonded Supramolecular Chain and Sheet Formation by Coordinated Guranidine Derivatives 111 33-83 Hupp JT (2006) Rhenium-Linked Multiporphyrin Assemblies Synthesis and Properties 121 145-165... 

Ercolani, G., (ed. E. Alessio) (2006) Noncovalent Multiporphyrin Assemblies, Springer, Berlin. 

This multithreading process was realized in the construction of multiporphyrin assemblies from macrocycles with pendent zinc(II) or gold(III) meso-tetraarylporphyrins.59 These assemblies are shown in Figure 2.26,... 

Synthetic strategies and structural aspects of metal-mediated multiporphyrin assemblies 06ACR841. 

Two of the classical bis-nitrogen ligands to assemble porphyrins (predominantly zinc metallated) are the bidentate l,4-diazabicyclo[2.2.2]octane (DABCO) and 4,4 -bipyridine (bipy). Other di-topic nitrogen-ligands studied include hydrazine, 4,4 -bipyrimidine, diaza-pyrene, 5,5 -dicyano-2,2 -bipyri-dine, perylene-bisimide, extended bipyridine units and non-covalently linked di-pyridyl ligands via bipy-metal interactions. The formation of various bis-porphyrin and multiporphyrin assemblies using these versatile ligands were studied in detail by Sanders, Anderson, Hunter, Branda and many others. The structures of the supramolecular multi-porphyrin architectures are schematically represented in Fig. 9. 

In fact, hardly any donor atoms other than nitrogen have been used to create multiporphyrin assemblies. Using hard Lewis acids as central metal opens the possibility to bind two axial ligands on either side of the porphyrins. With ditopic Ugands such as diols this can lead to polymerization. However, a few examples can be found in the Uterature, where the central metal of the porphyrin is axially coordinated by oxygen, sulfur or selenium to assemble porphyrins. The use of (non-porphyrinic) phosphine ligands apparently has so far not been successful in the construction of supramolecular multiporphyrin arrays. 

The methodologies to design and synthesize multiporphyrin assemblies on a rational basis have advanced to the point, where almost any metallopor-phyrin can be incorporated into oligomeric heterometalUc arrays. The use of... 

Fig. 3 Schematic drawing of the square planar and octahedral metal fragments (and of their precursors) most commonly used in the metal-driven construction of multiporphyrin assemblies...

According to the definition of multiporphyrin assembly given in the Introduction (Sect. 1), a dimeric hetero-assembly can be formed by A—A and B—B monomers only if both contain porphyrin subunits. An example is given by the dimer 24 (meso-aryl groups omitted) whose stability constant, iCsa = 3x10 mol 1, was determined in CH2CI2 by a fluorescence titration... 

Significant developments in the construction of multiporphyrin assemblies have been seen over recent years and many more will be seen in the years to come. No doubt the rational design of complex and intriguing supramolecu-... 

Chambron J-C, Heitz V, Sauvage J-P (2000) Noncovalent multiporphyrin assemblies. In Kadish KM, Smith KM, Guilard R (eds) The porphyrin handbook, vol 6. Academic, New York, p 1... 

This book summarizes recent work on metal-mediated and hydrogen-bonded multiporphyrin assemblies which are stable enough to be characterized in solution. Assemblies coordinated only in soUds (e.g. crystals) are not included. Emphasis is given on the photophysical and molecular recognition properties of the supramolecular multiporphyrin systems. 

Chambron, J.-C. Heitz, V. Sauvage, J.-P. Noncovalent Multiporphyrin Assemblies. In The Porphyrin Handbook,... 

In the following discussion, we will focus on the construction of multiporphyrin assemblies, whose components are held together by noncovalent bonds. We will restrict our discussion to discrete molecular species and thus we will not include micelles, membranes or films. The types of interaction described here are diverse and include hydrophobic interaction, hydrogen bonding and coordination bonds (metal-ligand interaction) in particular. 

---