Molecular polygons

Figure 4.1 Schematic depiction of routes for the self-assembly of molecular polygons.

Figure4.12 Self-assembly of chiral Pt-alkynyl molecular polygons.

When the linear trans-[Pt(PEt3)2Cl2] was used to connect the bis (alkyne) ligand 15a-c, a mixture of different sizes of chiral metallocycles [trans-(PEt3)2Pt(15a-c)] , (rt = 3-8,19-24) was obtained [26], Each of the chiral molecular polygons 19-24 was purified by silica-gel column chromatography and analytically pure 19-24 was obtained in yields (%) of 5,18,16,10,5, and 4, respectively (Figure 4.12). Compounds 19-24 have been characterized by H, and P H NMR spectroscopy,... 

FAB and MALDI-TOF MS, and IR, UV/Vis, and circular dichroism (CD) spectroscopies, and microanalysis. The limited conformational flexibility of the bridging ligand is key to the facile one-pot self-assembly of chiral molecular polygons 19-24. 

Jiang, H, and Lin, W. (2005) Chiral molecular polygons based on the Pt-alkynyl linkage Self assembly, characterization, and functionalization. 

The room temperature emission characteristics of the molecular polygons varied. The emission maximum of rectangle A (R = - (CFbhiCHj) was located near 600 nm and its intensity was dependent on the solvent. 

In general, emission intensity in the molecular polygons examined here was significantly diminished from that of the monomolecular rhenium complexes. This can be attributed to a decrease in the emission lifetime due to quenching by the additional vibronic components. 

Application of the lessons learnt in the self-assembly of molecular squares has led to successful strategies for preparing further molecular polygons (and, in particular, new triangles, rectangles and hexagons) as well as examples of particular other polyhedra. ... 

Self-assembly methodologies have been used for the designed synthesis of a range of discrete, metallocyclic 2-D and 3-D coordination compounds. The topologies of many such compounds resemble well-known geometric shapes, so that they are widely referred to as molecular polygons (2-D) or molecular polyhedra (3-D). 

Self-assembly of chiral molecular polygons (reproduced with permission from reference... 

Unlike helicates, molecular polygons are hollow, containing a central cavity similar to simple macrocyclic host molecules (see Chapter 2, Section 2.2). The assembly processes can be templated around a guest in a novel variant of the... 

Chiral molecular polygons have been prepared via treatment of either (R)- or (S)-254 with [trans-PtCl2(PEt3)2] (Scheme 6.34) [89]. This one-pot reaction affords a mixture of polygons 255-260, with highest yields observed for the tetramer 256... 

Scheme 10.16. Chiral platinum-containing molecular polygons with potential enantioselective catalytic activities.

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