Crystal structures hexanuclear complexes

Apart from the gold(i) system, bis(mesityl)mercury(ii), which also possesses a heavy metal center with strong relativistic effects, has been used for the synthesis of the mixed metal silver(i) aryl complexes, [HgAg2(mes)X2]2 (X = OTf 13a (Figure 7), C104 13b).33 X-ray crystal structure analysis of 13a revealed its hexanuclear nature with the... 

FIGURE 78 Syntheses of hexanuclear and octanuclear samarium cluster complexes and their reaction with dinitrogen to afford tetranuclear cluster species containing a N2 ligand derived from dinitrogen reduction (top). The crystal structures of the hexanuclear (bottom left) and octanuclear (bottom right) clusters are shown (redrawn after Ganesan et al 2001). 

FIGURE 124 Clockwise from top left molecular structure of tpen, crystal structure of a dinuclear hydroxo complex [La(tpen)(/r-OH)]2(/r-V OTf) +, crystal structure of cationic hexanuclear cluster [La6(tpen)4(MeCN)2(H20)2(/r3-7j 7j 7j C03)4 (/t3-7] 7] 7] C03)2], and its core motif (redrawn after Natrajan et al., 2006). 

The hexanuclear complexes of Cu(II) and Ni(II) with polysiloxanolate ligands display different magnetic behavior [20]. The Cu(II) complex shows a ferromagnetic coupling with a ground state of S=3 [113], while in the case of the Ni(II) complex the ground state has S=0 [114]. Analysis of the crystal structures reveals a similar structure of the complex, but in the case of the nickel atom a chloride anion is placed in the center of the channel in order to complete the octahedral coordination whilst the copper atom has square pyramidal coordination (see Fig. 11). 

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