Trinuclear networks

The first example of a symmetric triangular mixed-valent triruthenium complex 99 has been obtained by thermal treatment of Ru(acac)2(MeCN)2 with substituted 2-thiouracil (equation 66). Although the usual coordination mode of the acetylacetonate is present in the trinuclear compound, the y-carbon atom of one of the coordinated acetylacetonato units of the parent Ru(acac)2(MeCN)2 links to a ruthenium atom forming the trinuclear network. The factors which are primarily involved in the ruthenium-mediated C—S bond cleavage of the stable thiouracyl are not clear. It was suggested that the process starts with the initial coordination of thiouracyl to ruthenium followed by cleavage of the C—S bond and subsequent nucleation. ... 

In this section, I will comment on selected examples of luminescent supramolecular architectures built through Au-Au interactions, both in the solid state and/or, when there is enough evidence, in solution. This topic will be divided into four parts based on the unit that by repetition gives rise to the supramolecular network, that is mononuclear, binuclear, trinuclear and higher nuclearity systems. 

In the case of the trinuclear [ t-N1,C2-bzimAu]3 (bzim = benzylimidazolate), in addition to the extended structures that form with other metals (see Section 6.3), it also forms supramolecular networks, acting as an electron donor with small organic acids [48]. For example, it reacts with TCNQ (tetracyanoquinodimethane) giving rise to a columnar structure in which each TCNQ molecule is sandwiched between two units of the trinuclear complex in a face-to-face manner. Thus, the repetition of this pattern leads to a stacking of the type (Au3)(Au3)( t-TCNQ)(Au3)... 

Besides the network and one-dimensional polymeric Pcs, binuclear, binuclear double decker [16-22], binuclear clamshell and double decker clamshell [9,23-26], trinuclear [27-31], tetranuclear [9,32], pentanuclear [33], and octanuclear Pcs [34] have been reported. 

Figure 2.5.8 Trinuclear, tetranuclear, and hexanuclear macrocyclic rings present in two-dimensional and three-dimensional networks of triorganotin cyanometalates...

ResBrg is similar to Re3Cl9 but the iodide, which is a black solid and is similarly trinuclear, differs in that it is thermally less stable and only 2 Re atoms in each duster are linked to adjacent clusters, thereby forming infinite chains of trimeric units rather than planar networks. 

Figure 4 Single-crystal X-ray structure of M MOF-1 showing that the framework is composed of trinuclear [Zn3(COO)g] SBUs (b) bridged by BDC moieties to form 3 tessellated 2D sheets (c) that are further pillared by the Cu(Pyen) rmits (a) to form a 3D network having curved pores of about 5.6 X 12.0 along the c axis (d) and irregular ultramicropores along the b axis (e). Variation of isosteric enthalpy of adsorption (f) and activation energy (g) with amount adsorbed for H2 and Dj on M MOF-1 (Reprinted with permission from Ref 4. Copyright (2008) American Chemical Society.)...

Cu(mal)2(H20)2], respectively, which are linked by electrostatic forces, van der Waals interactions, and an extensive network of hydrogen bonds involving carboxylate groups and water molecules. The trinuclear copper(II) unit is the next condensation of dinuclear unit in which another pendant [Cu(H20)4] group has been symmetrically attached to the central [Cu(mal)2(H20)2] unit (Fig. 19c). Whereas the mononuclear and dinuclear entities could also be obtained under the adequate crystallization conditions. 

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