Synthesis,Characterization, and Reactivity of Cationic Palladium(II) and Platinum(II) Iodo Complexes Containing a Linear or a Tripodal Aminophosphine. The X‐Ray Crystal Structures of [Pd{HN(CH2CH2PPh2)2}I]I and [Pd3{N(CH2CH2PPh2}3)2I4]I2

The complexes [M(PNHP)I]I (PNHP = bis[2‐(diphenylphosphino)ethyl]amine; M = Pd ( 1 ), Pt ( 2 )) and [M(NP₃)I]I (NP₃ = tris[2‐(diphenylphosphino)ethyl]amine; M = Pd ( 3 ), Pt ( 4 )) were prepared by interaction of the appropriate aminophosphine in CH₂Cl₂ with aqueous solutions containing [MCl₄]^2— salts and NaI in a ratio 1:4. Complexes 2 and 3 form the polynuclear compounds [Pt₂(PNHP)₃]I₄ ( 2a ) and [Pd₃(NP₃)₂I₄]I₂ ( 3a ) in the presence of coordinating solvents such as the mixture CD₃OD/D₂O/DMSO‐d₆ and CH₂Cl₂/CH₃OH, respectively. Complex 1 consists of distorted square‐planar cations [Pd(PNHP)I]⁺ and iodide anions able to establish short N‐H···I interactions of 2.850Å. The aminophosphine adopts a boat conformation and is coordinated to palladium in a tridentate chelating fashion. The crystal structure for cations of 3a reveals the presence of two types of distorted square‐planar Pd^II atoms, PdNP₂I and trans‐PdP₂I₂, NP₃ acting as tridentate chelating and bridging ligand, respectively. On the basis of ³¹P {¹H} NMR data it has been shown that each distorted square‐planar Pt(II) centre of 2a contains one PNHP acting as tridentate chelating ligand with the other aminophosphine bridging the two metals via the P atoms. Complexes 3 and 4 were shown by ³¹P {¹H} NMR to have the metal atom bound to the three P atoms of NP₃ and one iodo ligand. Additions of AcCysSH and GSH to 4 result, by a ring‐opening process, in the formation of [Pt(NP₂PO)(SR)] (RS = Acys ( 4a ), GS ( 4b )) in which the ligand contains a dangling arm phosphine oxide group and the platinum atom achieves the four‐coordination involving the N atom of the aminophosphine. Compounds [Pt₂(PNHP)₃]Cl₄ ( 2a′ , 2a″ ), [PtAu(PNHP)₂I]I₂ ( 2b ), and [Pt(PNHP)(ONO₂)](NO₃) ( 2c ) were detected in some extent in solution by reaction of complex 2 with Au(tdg)Cl (tdg = thiodiglycol), AuI and excess AgNO₃, respectively. While 1 does not react with AuI, complex 3 affords the heterobimetallic complexes PdCu(NP₃)I₃ ( 5 ), PdAg₂(NP₃)I₄ ( 6 ) and PdAu(NP₃)I₃ ( 7 ) by interaction with the appropriate iodide M′I (M′ = Cu, Ag, Au) via a chelate ring‐opening.