Organolead polymers

Kochkin, D. A., Azerbayev, I. N. Organotin and Organolead Monomers and Polymers, Alma-Ata, Nauka Publishers 1968, (Russ.)... 

Catena-[(p2-acetoxy)-acetoxydiphenyllead(IV)] (19) is among the few structurally characterized hypervalent hexacoordinate organolead acetates. The latter forms a polymer via intermolecular O —y Pb interactions152. 

Examples of supramolecular association as a result of intermolecular organolead-sulphur interactions are rare and compounds such as Me3PbSMe and Pl PbSPh are monomeric in the solid state463. In contrast, triphenyllead pyridine-4-thiolate, d-Pl PbSCsFLjN464, is a chain polymer as a result of intermolecular N—Pb interactions. The cyclic dithiolate 2,2-diphenyl-l,3,2-dithiaplumbolane 177465 self-assembles in the solid state via intermolecular tin-sulphur interactions into a one-dimensional polymeric array. The intramolecular Pb—S bond lengths amount to 2.52(2) and 2.49(1) A and the intermolecular Pb—S distances are 3.55(2) A. 

Early examples of structurally characterised organolead coordination polymers with Pb—N interactions are trimethyllead cyanide, Me3PbCN335, dimethyllead dicyanide, Me2Pb(CN)2337, and trimethyllead azide, Me3PbN3 (179)467,468. The latter compound forms a linear chain polymer with a /X2-N atom symmetrically bridging the pentacoordinated lead centres [Pb—N 2.54(1) A], The N—Pb—N angle [178.6(5)°] deviates only slightly from the ideal value of 180°. 

Organic derivatives of Group IV find applications in diverse areas. Especially important are the silicone polymers, organotin compounds as stabilizers for plastics and as biocides and organolead antiknock agents for petrol. 

In the past few years unsaturated organolead compounds have become of special interest. They are starting materials for lead-containing polymers (125) (see Sections 2 and 4 below), and the unsaturation makes the Pb—C bond especially reactive. For their preparation the procedures described in Sections II,B,C are mainly of interest. 

For example, polymerization of ethylene or propylene at 200-400 C, 1-250 atm gives only liquefied polymers. However, with Ziegler type eatalysts of tetraethyllead and metal halides (halides of Ti, Mo or V), produces the polymerization at 90-180 °C form an atmospheric pressure to a high pressure gives erystalline polymers [39], Organolead compounds have been investigated as catalysts for polyesters, polysulfones, polyurethanes, etc. [9,39]. 

There are a limited number of examples of lead-containing polymers. This is attributed partially to the insolubility of suitable organolead monomers. In the 1970s, Carraher and Deremo Reese reported the synthesis and thermal properties of Iead(IV) polyesters. Reaction of dialkyllead dichloride (224) (Scheme 56) in DMSO with dicarboxyUc acids (225) in 50% DMSO-H2O led to the isolation of the lead containing polymers (226) (Scheme 56). 

The synthesis of organolead polymers has been reported by Fischer and coworkers by combining aqueous solutions of MejPbCl and K4[M(CN)6] (M=Fe, Ru), assemble to give supramolecular assemblies. Edelmann and coworkers have also reported the supramolecular assembly of triphenyllead(IV) dimethylphosphino-dithioate to produce a linear polymer with the structure 227 It was noted that the phosphinodithioate ligands were bridging with nearly linear S-Pb S segments. 

A general introduction of silicon-, germanium-, tin- and lead-containing polymers is presented in Chapter 6 of Volume 1 in this series. A more extensive treatment of organogermanirrm, organotin, and organolead polymers is presented in this volume in Chapter 9, Chapter 10, and Chapter 11, respectively. The remainder of this volume (Chapters 2-8) focuses attention of special aspects and new developments in silicon-containing polymers. 

The use of organolead compounds as paint biocides was also widely recognized, but tiiese lost out to the less toxic and better accepted organotin monomers and polymers. ... 

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