Synthesis and Characterization of Heterotrinuclear Complexes of Nickel and Palladium with Pyridinecarboxylate as Bridging Ligands

Abstract

Heterotrinuclear pyridinecarboxylate complexes of nickel(II) and palladium(II) of the types [Ni(mcN 3 )(pyridinecarboxylate)] 2 {μ-[Pd(C 6 F 5 ) 2 ]}(PF 6 ) 2 [mcN 3 = 2,4,4-trimethyl-1,5,9-triazacyclododec-1-ene (Me 3 -mcN 3 ) or 2,4,4,9-tetramethyl-1,5,9-triazacyclododec-1-ene (Me 4 -mcN 3 )] have been prepared by two different routes. The corresponding monomeric pyridinecarboxylate complexes of nickel and the

Spacer directed metallo-supramolecular assemblies of pyridine carboxylates

“…Pyridine donating monodentate ligands with free carboxylic acid ends are potential metalloligands upon deprotonation, thus providing a viable pathway to heterometallic complexes [37,71] (Fig. 4).…”

“…Among the few exceptions are [Ni(nic)(tetramethyltriazacyclododecene)] + [71] ( Fig. 6) and Mo 2 (isonic)(formadinate) 3 [78] in which the active donor comes from the pendant pyridine, enabling the complexes to serve as nitrogen metalloligands.…”

“…This mobility and flexibility enable the ligand to self-select the metals and self-organize the resultant framework. The presence of both pyridine and carboxylate functions therefore gives these ligands maximum prowess to cope with the demands of different metals and adapt to different forms of metal connections [31,71,72,[74][75][76][87][88][89] (Fig. 1).…”

“…More common are those donors that have similar characteristics (such as hardness) but show sufficient selectivity to differentiate metals of related properties, such as the isoelectronic Rh(I)/Pd(II) and Pt(II)/Au (III). Typical examples of such are the N,O donors such as amino acids [46][47][48], amino-alkoxides [49], carboxyimidazoles [50][51][52], pyrazine carboxylates [53][54][55][56][57], pyridine alkoxides [58][59][60], pyridine ketones [61,62], pyridine esters [63], pyrimidine carboxylates [64,65], pyridine carboxylates [31,[35][36][37][38][39][40][41][42][43][44][45][66][67][68][69][70][71][72][73][74][75][76][77][78][79] and pyrazole carboxylates …”