Tetranuclear rhodium(I) macrocycle containing cyclodiphosphazane [Rh2(μ-Cl)2(CO)2{(tBuNP(OC6H4OMe-o))2-κP]2 and its reversible conversion into trans-[Rh(CO)Cl{(tBuNP(OC6H4OMe-o))2-κP}2]

The 1:1 reaction between cis-[(BuNP)-Bu-t(OC6H4OMe-o)](2) (2) and [Rh(mu-Cl)(CO)(2)](2) affords novel tetranuclear rhodium(l) macrocycle (3) containing two cyclodiphosphazanes bridged by two [Rh(mu-Cl)(CO)](2) moieties, whereas the corresponding 4:1 reaction affords trans-[Rh(CO)Cl-{((BuNP)-Bu-t(OC6H4OMe-o))(2)-kappa P}2] (4).