Metal binding in chelation therapy: the crystal structure of D-penicillaminatolead(II)

Fundamental Coordination Chemistry, Environmental Chemistry, and Biochemistry of Lead(II)

“…The crystal structure for D-penicillaminatolead(II) (195) [ Fig. 13(a)] reveals that multiple ligand molecules are bound to each lead ion in the solid state, resulting in an extended structure.…”

“…However, pioneering structural studies by Raymond, Reger, and others have revealed that Pb(II) exhibits a rich and interesting coordination chemistry (39,170,(176)(177)(178)(179)(180)(181)(182)(183)(195)(196)(197)(198): lead(II) binds to a broad range of donor groups, assumes a wide range of coordination numbers, and can exhibit a stereochemically active 6s lone pair. A survey of the Cambridge Structural Database (CSD) (199,200) reveals 295 Pb(II) structures for which coordinates have been deposited, including both extended structures and discrete complexes.…”

Coordination chemistry of two heavy metals: I, Ligand preferences in lead(II) complexation, toward the development of therapeutic agents for lead poisoning: II, Plutonium solubility and speciation relevant to the environment

“…The crystal structure of the 1: 1 lead(II), D-penicillamine complex shows the ligand acting as a tridentate chelator and an oxygen and a sulphur of neighboring molecules forming two weak bonds to lead. 70 A thiohydroxamic acid linked to the penicillamine primary amine could replace the weakly bound oxygen and sulfur atoms in the structure. The lead complex of a ligand containing these two groups should have a high formation constant, based on log~ for the 1: 1 D-penicillamine, lead(II) specie~, 13.5 71 and log~ for the 1:1 N-methylacetothiohydroxamate, lead(II) species, 6.88.…”

“…75 The tertiary amine nitrogen in 2-(morpholin-4-yl)ethanethiolatolead(II) nitrate has a bond distance with lead of 2.61A. 76 ) Lead-thiohydroxamate bond angles were fixed; but the leadpenicillamine angles were not reported by Freeman, 70 and therefore were allowed to vary in the energy minimization.…”

“…69,73 A prototype ligand where penicillamine and N-methylacetothiohydroxamic acid are joined by a 2-ethyl-benzyl group is shown as a lead complex in Figure 31. The structure was generated using the molecular dynamics software package, CAChe 74 , and lead-donor atom bond distances and from the lead-penicillamine 70 and bis(Nmethylacetothiohydroxamato)lead 18 crystal structures. The lead-nitrogen bond was fixed at 2.55 A in the energy minimization based on the lead-nitrogen distance in lead isopropylxanthate-pyridine where the lead is five-coordinate is 2.55A.…”