pH as a Structure Director in the Synthesis of Copper Molybdates

摘要

This paper deals with the investigation of the reactions of aqueous molybdates in the presence of copper ions under varying pH to obtain new copper molybdates and rationalize the structures formed in terms of the self-assembling nano-building blocks of polyoxomolybdates (POMs). The reactions led to the precipitation of porous copper molybdates: 1D polymeric anions in (NH_4)_6[{Cu(H_2O)_4} {Mo_(36)O_(112)(H_2O)_(16)}]_(21)H_2O,1, a 3D framework bimetallic oxide in Cu_3Mo_2O_g, 2. Our results reported here clearly suggest that copper complexes formed during the initial stages of the reaction probably dictate the architecture of the final solids. Interestingly the magnetic properties studied on these compounds showed that 1 shows paramagnetic ordering since magnetically active centres i.e. Cu(ll) are separated by large diamagnetic centres of {Mo_(36)} cluster anions where as 2 shows the dominance of antiferromagnetic near-neighbor interaction.