Lead carboxylates, coordination polymers

Safarifard V, Morsali A. Mechanochemi-cal solid-state transformations from a 3D lead(II) chloride triazole carboxylate coordination polymer to its bromide/thiocyanate analogs via anion-replacements precursors for the preparation of lead(II) chlo-ride/bromide/sulfide nanoparticles. Cryst Eng Commun 2012 14(16) 5130. 

Safarifard V, Morsali A. Solid state syntheses of nano lead(II) iodide triazole carboxylate coordination polymer from its bromide/ thiocyanate/chloride analogs via mechanoche-mical crystal to crystal transformations. Inorg Chim Acta 2013 405 203- . 

Safarifard V, Morsali A. Sonochemical syntheses and characterization of nano-sized lead(II) coordination polymer with ligand lH-1,2,4-triazole-3-carboxylate. Ultrason Sonochem 2012 19(2) 300-6. 

Nanoparticles of a two-dimensional coordination polymer, containing lead complexed with IH-1,2,4-triazole-3-carboxylate, have been synthesized by a sonochemical process [29]. 

By thermal decomposition of the nano 2D MOCP precursors [Pb(2-pyc)(NCS)] and [Pb(3-pyc)(NCS)] (.Hpyc = pyridinecarboxylic acid) at 400°C, nanorods and nanoplates of PbS were obtained (Figure 3.4) [141]. The sizes and shapes of the nanostructures are related to the structure of the coordination polymers. An identical thermal processing on the [Pb(L4)(p3 3-NCS)(H20)] HL4 = lH-l,2,4-triazole-3-carboxylic acid) precursor has led to the formation of a mixture composed from PbS and Pb (S0 )0 nanoparticles [142]. This reveals that the composition or crystal packing of the initial MOCP may lead to different final products. 

Another aspect of tin as a constituent of electrode material is shown by tin(IV)TPP complexes incorporated into PVC membrane electrodes. These increase the selectivity to salicylate over anions such as Cl-, Br- I-, I()4, Cl()4, citrate, lactate and acetate. The specificity is attributed to the oxophilic character of the Sn ion in TPP at the axial coordination sites. Indeed, carboxyl groups incorporated into the membrane polymer compete for these binding sites. The complete complex structure is important. Substitution of TPP with octaethylporphirine results in loss of salicylate selectivity231. Preparation and analytical evaluation of a lead-selective membrane electrode, containing lead diethyldithiocarbamate chelate, has also been described232. 

Condensation of dicarboxylic acids and both diaryl- or dialkyllead dichlorides generated lead-containing polymers, 101.233>234>235 The IF polymerization method was used and higher yields resulted using the bis-carboxylate salts. The lead centers in these polymers can exist as tetrahedral or octahedral geometries. The octahedral lead centers result from further coordination of two carbonyl oxygens to the lead atom. IR studies demonstrated both lead structures exist within the polymers. 

In principle, such protection using the carboxylate salt is feasible, but an exchange of the metal cation coordinated to the carboxylate salt has to be taken into account. This would lead to a transfer of the protected olefin between the titanocene and the active catalyst. Copolymerization experiments of Tim/Iia with ethene lead to the desired titanocene-protected copolymers in yields comparable to ethene homopolymerization. Hydrochlorination of the protected polymer regenerates the protecting Cp2TiCl and the free carboxylic acid of the polymer (Scheme 19). 

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