A metalloligand appended with benzimidazole rings: tetranuclear [CoZn3] and [CoCd3] complexes and their catalytic applications

Abstract

A novel Co³⁺-based metalloligand 1 offering appended benzimidazole rings has been prepared and utilized for the synthesis of tetranuclear [CoZn₃] (2 and 2-Cl) and [CoCd₃] (3) heterometallic coordination complexes (HCCs). Crystallographic studies of 2-Cl and 3 illustrate coordination of three secondary metal ions (Zn²⁺/Cd²⁺) to the appended benzimidazole rings of 1 thus producing tetranuclear HCCs. Both HCCs were utilized as heterogeneous catalysts for Knoevenagel condensation and Henry reactions. The stability and recyclability experiments illustrate the stable nature of both HCCs during the catalysis.