Tetrahedral complexes supramolecular

The first example of chiral tetranuclear supramolecular assembly 5.27 was reported by Saalfrank and coworkers in 1988. Thus the complex [(NH3)4n(Mg (22)5] (5.27) was obtained by serendipity upon treatment of the doubly bidentate ligand 22, which is formed in situ from malonic ester and oxalyl chloride, with MeMgl in aqueous ammonium chloride solution (Scheme 5.13). Later an improved one-pot reaction was used to prepare such tetrahedral complexes of magnesium, manganese, cobalt and nickel by treating the bis(chelate) ligand 22, obtained in situ, with MeLi/MCl2 followed... 

Square-planar zinc compounds predominate with these ligand types as would be predicted. This is in contrast to the prevalence of tetrahedral or distorted tetrahedral geometries for four-coordinate species that have been discussed thus far. Zinc porphyrin complexes are frequently used as building blocks in the formation of supramolecular structures. Zinc porphyrins can also act as electron donors and antenna in the formation of photoexcited states. Although the coordination of zinc to the porphyrin shows little variation, the properties of the zinc-coordinated compounds are extremely important and form the most extensively structurally characterized multidentate ligand class in the CSD. The examples presented here reflect only a fraction of these compounds but have been selected as recent and representative examples. Expanded ring porphyrins have also... 

A plethora of polynuclear copper(I) complexes with bi-, tri-, and tetracon-necting dithiophosphato ligands have been discovered. These include cyclic dimers, [CuS2P(OEt)2 PPh3]2,43 tetrahedral Cu4[S2P(OPr )2]4,44 prismatic Cu6 S2P(OR)2 6, cubane Cu8(p8-E )[S2P(OEt)2]6 (E = S, Se),45 (also known for silver)46 and [Cu8 S2P(OPr )6(p8-X)][PF6] (X = Cl, Br).47 A supramolecular chain-like array of cubane units interconnected through iodine bridges was found in Cu8(S)[S2P(OEt)2]6(p-I) x.48... 

CONTENTS Preface. George W. Gokel. Cryptophanes Receptors for Tetrahedral Molecules, Andre Collett, Jean-Pierre Dutasta and Benedict Lozach. Inclusion Polymerization in Steroidal Canal Complexes, Kiichi Takemoto, Mikiji Miyata. Functionalized Tetraazamacrocycles Ligands with Many Aspects, Thomas A. Kaden. Calixarenes as the Third Supramolecular Host, Seiji Shinkai, Kyushu University, Japan. Fluorescent Chemosensors for Metal and Non-Metal Ions in Aqueous Solutions Based on the Chief Paradigm, Anthony W. Czamik. Index. 

In the complex [Cu(L)4]PF6 (L = 3-cyano-6-methylpyrid-2(lH)-one), the hydrogen-bonded linkage involves the amido R2(8) supramolecular synthon [Fig. 20.4.15(a)]. Each Cu(I) center serves as a tetrahedral node in a fourfold interpenetrated cationic diamondoid network. The tetrahedral metal cluster [Mn(/z3-OH)(CO)3]4 can be used to construct a diamondoid network with the linear 4,4/-bipyridine spacers [Fig. 20.4.15(b)],... 

Although the cyclic dimers are connected by additional H-bonds, the authors did not observe a super-tetrahedral network. Notably, a 2 1 alcohol-amine complex 14 15, was also observed [41] between 4-methoxyphenol (15) and methylhydrazine (14) (Scheme 5). Thus, a dimer formed by a primary amine and a secondary amine in such cases does not have the general requisites to generate a supramolecular architecture. 

In the dimeric version of die complex each Ag(I) ion binds three 4,5-ethylenedithio-l,3-di-diiole-2-thione molecules (149) through die thiono S atoms (Ag—S distance ca 0.25 nm), and two such units become paired as shown in 150 (Ag—S distance between paired units is ca 0.30 nm)226. A polymeric complex [Ag(C5H4S5)2NC>3] (151) also exists, where every Ag atom coordinates two thiono and two heterocyclic S atoms of four different 149 molecules. The Ag atoms have distorted tetrahedral coordination, with two distinct Ag—S bond distances, 0.25612 nm (to thiono) and 0.28268 nm227. In both the dimeric and the polymeric versions supramolecular organization is attained by S - -S contacts between neighboring units. 

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