Metallophilic interaction

A transmetallation reaction was used to synthesize the complex [Au(C6F5)2][Bi (C6H4CH2NMe2-2)2j [119] and the crystal structure of the complex was studied by X-ray diffraction. This is the first example of metallophilic interactions of the Bi(111) atom and this is the most interesting characteristic of this complex, the presence of Au Bi distances of 3.7284(5) A. 

Hermann, H.L., Boche, G. and Schwerdtfeger, P. (2001) Metallophilic Interactions between Closed-Shell Copper(I) Molecules - A Theoretical Study. Chemistry A European Journal, 7, 5333-5342. 

Scheme 5 shows a group of alkynylgold(i) complexes for which the studies focused on the UV-VIS electronic absorption and emission properties. Most of these compounds are of the type [(L)AuC=CR], for which the methods of synthesis have been summarized above. The products were found to show phosphorescence in various polymorphs and crystal forms of solvates. Although there are no metallophilic interactions discernible in the crystal between most of the monomers due to the steric effect of the large tertiary phosphines, there is nevertheless strong excitonic coupling based on other weak interactions, which depend on the organization of the molecules in the crystal.105,106... 

As in the case of the gold-silver analogous systems, perhaps the most productive method for preparing extended systems through metallophilic interactions is the acid-base process, in which basic gold(I) precursors react with metallic Lewis acids forming supramolecular networks via acid-base stacking. The cation-anion interactions assist the formation of extended chains. 

The most common strategy in the synthesis of heteronuclear complexes is the use of bidentate donor ligands bearing different donor centers. In that way both donor atoms can be coordinated selectively to two different metal centers in a consecutive way. If the space between the donor atoms of the ligands is short, interactions between both metals usually appear, normally intramolecular. Sometimes, albeit not very often, the bidentate units bind to one another, leading to extended structures through metallophilic interactions. As we have commented, in the case of gold-silver derivatives the number of luminescent studies of these derivatives is very scarce. 

As described above, among the several closed-shell metal ions that form luminescent supramolecular entities with gold, thallium(I) forms the most numerous examples. While aurophilic attractions can be considered the upper extreme of the metallophilic interactions (with values up to 46 kJ mol-1), intermetallic contacts involving T1(I) centers appear as the weakest ones (even <20 kJ mol-1),46 which is explained by the enhancement of the Au---Au interactions and the weakening of the Van der Waals attractions between the s2 metal atoms produced by the relativistic effects.47 Nevertheless, the complexes in which this interaction appears are surprisingly stable, with additional electrostatic, packing forces, or the ligand architecture, responsible for this fact. 

Recently the metallophilic interaction between heavy elements has earned considerable interest see Polynuclear... 

Cases of study of double salts in which no metallophilic interaction is involved are also known. In this respect, Schlofer and coworkers first reported an energy transfer studies in Cr(III)-based complexes of formula [Cr(urea)e] [CrfCNlel X3H2O. Afterward, Kobayashi 162,163), Hauser 164-166), and Kaizu 167-169), reported on quenching studies in Ru(II)/Cr(III) and Os(II)/Cr(III) mixed double complex salts. 

In short, it is clear that gold makes an essential contribution to metallophilic interactions. Thus, the design of synthetic strategies to prepare systems with these bonds of unique versatility and flexibility must include gold as an essential building block. 

Another type of interactions used successfully as template to steer olefins is the metallophilic interaction based on monovalent ions with electronic configuration The most common one is the argentophilic... 

Kishimura, A. Yamashita, T. Aida, T. Phosphorescent organogels via metallophilic interactions for reversible RGB-color switching. J. Am. Chem. Soc. 2005,127, 179-183. 

Figure 3.13 The net in lAg(4,4 -bipyridine)JN03 is held together by long Ag-4,4 -bipyridine-Ag links and by shorter Ag(I)-Ag(l) metallophilic interactions [40,41],...

In this type of complexes, the luminescent behavior is generally considered to be a consequence of the so-called metallophilic interaction. This interaction, also named metallophihcity, describes an intra- or inter-molecular interaction between two centers with a d closed-shell electronic configuration. The low coordination number is an important prerequisite since it minimizes the steric repulsions between the ligands in the abrogates... 

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