Tetranuclear Complexes Based on a Dynamic Metal−Metal Linkage, [(μ<sub>4</sub>-X)Rh<sub>4</sub>(CO)<sub>4</sub>(PNNP)<sub>2</sub>]<i><sup>n</sup></i><sup>+</sup> (X/<i>n</i> = RC⋮C/1 (Acetylide), C<sub>2</sub>/0 (Dicarbide))
Tetrarhodium complexes with a PNNP auxiliary, [(mu(4)-X)Rh-4(CO)(4)(PNNP)(2)](n+) (X/n = RCequivalent toC/1 (acetylide), C-2/0 (dicarbide); PNNP = 3,5-bis((diphenylphosphino)methyl)pyrazolato), are integrated mainly through M-X interactions and exhibit unique dynamic behavior associated with reversible metal-metal bond cleavage and recombination processes.