The reactions of cyclodiphosphazanes, cis-[(${}^t$BuN-𝜇)₂(PNC₄H₈O)₂] (1, R = NC₄H₈O; 2, R = NC₄H₈NMe ) (2) with [{RhCl(COD)}₂] and [{RhCl(CO)₂}₂] are described. The reactions of 1 or 2 with [{RhCl(COD)}₂] in 2:1 molar ratio yielded the mononuclear complexes [(COD)RhCl{(𝜇-N$^t$BuP)₂(NC₄H₈X)₂}] (3, X = O; 4, X = NMe) in good yield. Treatment of one equivalent of [{RhCl(CO)₂}₂] with four equivalents of 1 or 2 produced the trans-[(CO)RhCl{(𝜇-N$^t$BuP)₂(NC₄H₈X)₂}₂] (5, X = O; 6, X = NMe) complexes as pale yellow solids. On changing the molar ratio of [{RhCl(CO)₂}₂] and 1 or 2 from 1:4 to 1:1 resulted in the formation of tetranuclear complexes [{(CO)Rh(𝜇-Cl)(𝜇-N$^t$BuP)(NC₄H₈X)$\}_4$] (7, X = O; 8, X = NMe) under similar reaction conditions. The tetranuclear rhodium(I) complex 8 upon stirring with wet acetonitrile or in the presence of four equivalents of water at room temperature afforded a novel hydroxo bridged zwitterionic dirhodium(I) complex [{(ClRh(CO))₂(𝜇-OH)(MeNC₄H₈N)(𝜇-N$^t$BuP)₂(NC₄H₈NHMe)}] (9). The crystal structures of 5, 6 and 9 were established by single crystal X-ray diffraction studies.

The hydrolysis of cis-{ClP(𝜇-N$^t$Bu)2P(NH$^t$Bu)} (1) produced a mixed P^III/P^V derivative of cyclodiphosphazane, cis-{($^t$BuNH)P(𝜇-N$^t$Bu)₂P(O)H} (2). The treatment of 2 with elemental selenium resulted in the formation of the monoselenide, trans-{($^t$BuNH)P(Se)(𝜇-N$^t$Bu)₂P(O)H} (3) in good yield. The reactions of two equivalent of 2 with [Pd(𝜇-Cl)(𝜂³-C₃H₅)]₂ or [Ru(𝜂⁶-𝑝-cymene)(𝜇-Cl)Cl]₂ in dichloromethane afforded corresponding mononuclear complexes, [(𝜂³-C₃H₅)PdCl{($^t$BuNH)P(𝜇-N$^t$Bu)₂P(O)H}] (4) and [((𝜂⁶-𝑝-cymene)RuCl₂){($^t$BuNH)P(𝜇-N$^t$Bu)₂P(O)H}] (5). The treatment of 2 with M(COD)Cl₂ (M = Pd and Pt) in dichloromethane at room temperature gave [MCl₂{($^t$BuNH)P(𝜇-N$^t$Bu)₂P(O)H}₂] (6 M = Pd; 7 M = Pt) in good yield. Owing to the cis/trans isomerisation of the cyclodiphosphazane rings, the complexes 6 and 7 exist as a mixture of two isomers. Various NMR spectroscopic techniques were employed for structural elucidation. The molecular structures of 5 and 7 were established by single crystal X-ray crystallographic studies.