A phosphorescent copper(i) coordination polymer with sodium 3,5-dimethyl-4-sulfonate pyrazolate

A phosphorescent copper(I) coordination polymer with the sodium salt of 3,5-dimethyl-4-sulfonate
pyrazole (HLNa) has been prepared and structurally characterized. The presence of the SO3Na substituent
in position 4 of the pyrazole ring led to a 3D polymeric species in which an organic/inorganic/organic
sandwich motif is observed and repeated along the a axis through zig-zag chains of linear coordinated
Cu(I) ions. The inorganic core of the sandwich consists of a trapezoidal grid of Na-ions interconnected by
μ-(κO;κ2-O′,O″)-bridging sulfonates and bridging water molecules; H-bonds can be also found between
water molecules and SO3− groups. In the solid state, the copper derivative showed an interesting phosphorescent
behavior when irradiated with UV light, with a yellow emission (570 nm) and a good absolute quantum
yield (ΦPL = 0.44), together with a remarkable Stokes shift of 2.50 eV.