A flexible framework obtained from oxidative additions upon the binuclear complex [Ir2(µ-pz)(µ-SBut)(CO)2{P(OMe)3}2]: preparation and X-ray structures of [Ir2(µ-pz)(µ-SBut)(µ-L)(CO)2{P(OMe)3}2] and [Ir2(µ-pz)(µ-SBut)(µ-L)I2(CO)2-{P(OMe)3}2](Hpz = pyrazole, L = dimethyl acetylenedicarboxylate)