Polymeric nitrogen-bridged compounds

This synthetic gap has been bridged by the development of another process that involves the condensation polymerization of suitably constructed sllicon-nitrogen-phosphorus compounds. The most significant feature of this method is that it leads directly to fully P-C substituted polyphosphazenes, i.e., poly(alkyl/arylphosphazenes), [RR PN]p, where R and R are alkyl and/or... 

The compounds [CymB(Pz)3]Tl (136) and [FcB(Pz)3]Tl show polymeric structures, with bridging B(Pz)3 fragments in the solid state. This is a result of unfavorable steric interaction between the substituent on boron and the hydrogen atoms on the pyrazolyl ring 5-position. The structure of [Cym B(Pz)3]Tl is somewhat related, but it adopts a macrocyclic tetrameric structure rather than a linear polymeric structure. Ligands with secondary donors on the backbone may form additional bonds to the thallium atom. For example, in [HB(3-(2-pyridyl)Pz)3]Tl, weak TF"N interactions between pyridyl nitrogens and the T1 atom have been observed. HB(3-(2-MeOC6Fl4)Pz)3]Tl features close intramolecular TF 0 interactions. ... 

Lead(II) thiocyanate forms a linear polymeric compound with 2,2 6, 2"-terpyridine(terpy), [(terpy)Pb(SCN)2]oo, comprising seven-coordinate lead centers coordinating three pyridyl nitrogens and two A-bound and two 5 -bound bridging thiocyanates... 

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