The Stability of Metal N,N,N′,N′‐Tetrakis(2‐aminoethyl)ethane‐ 1,2‐diamine (=penten) Complexes and the X‐Ray Crystal Structure of [Tl(NO3)(penten)](NO3)2

Complex formation between N,N,N′,N′‐tetrakis(2‐aminoethyl)ethane‐1,2‐diamine (penten) and the metal ions Mn²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Ag⁺, Pb²⁺, and Tl³⁺ (in 1.00M NaNO₃ and 25°) was investigated by potentiometry and spectrophotometry. These are the first reported values of the stability constants for this ligand with Ag⁺, Pb²⁺, and Tl³⁺. The X‐ray crystal structure of Tl(NO₃)(penten)](NO₃)₂ was determined. In this structure, Tl³⁺ shows a coordination number of seven made up of the six N‐donors and one O‐atom of NO.