Dalton communications. Metal-ion recognition. Donor-set control of silver(I)/lead(II) discrimination using mixed-donor macrocyclic ligands

Lead Coordination and Organometallic Compounds: Classification and Analysis of Crystallographic and Structural Data

“…Another yellow derivative [85] has the Pb(ll) atom located non-centrosymmetrically within the macrocyclic cavity, being displaced from the mean plane of 0 3 N 2 donor atoms by 126 pm. There are three more yellow derivatives [86][87][88] in which the Pb(ll) atom is coordinated by one tridentate N-donor atom ligand and two monodentate O-donor atoms [86,87] or one bidentatate O-donor ligand [88] to give five coordination with the PbN 3 0 2 chromophore (Table 5A).…”

Macrocyclic ligand design. Effect of donor-set and ringsize variation on silver(I)/lead(II) discrimination within an extended series of dibenzo substituted rings

“…Although X-ray-quality crystals were not obtained for the lead complexes of L8, L' O and LI4, the previously reported structure of the lead@) complex of Li6 does indeed show very long Pb-S bonds of 3.175(4) and 3.141(3) A. 15 Considering now the effect on stability of variation of the donor-atom set. The interaction of silver(r) and lead(rr) with the N,-donor ring (L') or any of the O,N,-donor rings (L"-L8) in every case led to a stability difference between the respective complexes of less than a factor of 10.…”

“…In contrast to the situation for silver, LI6 provides only part of the co-ordination sphere of lead(rr) in [PbL'6(C104)2]. 15 The latter has a seven-co-ordinate structure with an approximate equatorial arrangement of the S,N,-donor set and axial perchlorate oxygens, giving an overall distorted pentagonal-bipyramidal geometry. The lead atom lies above the equatorial donor plane, being displaced 0.44 8, towards O( 11) of the co-ordinated perchlorate group.…”

“…All values k 0.1 unless otherwise indicated in parentheses; approximate values represent values obtained for a limited set of titration points. From ref 15…”

Pyrrole Azocrown Ethers. Synthesis, Complexation, Selective Lead Transport and Ion-Selective Membrane Electrode Studies

“…Previously macrocycle mediated transport experiments [14] have had as their focus silver/lead discrimination -metals that occur together in nature [15,16]. From an environmental point of view ideally Zn 2+ should not compete with the removal of Pb 2+ (or Cd 2+ ) [17].…”