Novel octanuclear copper(I) clusters [Cu8{(N)-(μ4-S)}4(μ3-I)2I2(PPh3)2] produced via reductive S-S bond cleavage of disulfide Schiff base ligands and their use as efficient heterogeneous catalysts in CuAAC click reaction

•Facile one pot synthesis of 5 novel [Cu8{(N)-(μ4-S)}4(μ3-I)2I2(PPh3)2] clusters.•X-ray structures, and DFT calculations to verify S-S bond cleavage and cluster formation.•Efficient use of the Cu8 clusters as catalysts in CuAAC click reaction.•Low catalyst loading (0.5 mol%) provides high yield of 1,2,3-triazoles (up to 97%).•The catalysts show excellent performance in water, under air at rt with good recyclability.