Synthesis and Investigation of Pyrazole-containing Platinum Complexes for the Design of Macrocyclic Molecules and Potential Two-electron Reagents PDF Download

Author: Stuart Alan Willison
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Languages : en
Pages : 200

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Book Description
A detailed study involving platinum(II) compounds with bis-2,6-pyrazolyl-phenyl type ligands have been undertaken in an effort to design a new architecture for building macrocyclic molecules with potentially coordinating tridentate ligands. Initial reports focused on platinum complexes with 2,6-bis-pyrazolyl-pyridine ligands. One complex, Pt(bpp)Ph +, exhibited an intense pink emission of the solid at 77 K, which is one of the first examples of a luminescent platinum compound with a bis-pyrazolyl-pyridine ligand. Herein we report the investigation of steric influence to promote C-H activation on the formation of monomeric and macrocyclic platinum(II) complexes, using methyl substituents on a series of anionic bis-pyrazolyl-phenyl ligands. Further studies of concentrated reaction mixtures at long reaction times result in exclusively trimeric products, whereas more dilute mixtures and shorter reaction times give only monomer products. Thus, careful control of the reaction conditions allows for selective activation of C-H bonds on the ligand giving isolated products of expected monomers and trimers, as well as surprising new dimeric products. In the course of our investigations of the monomeric platinum(II) products, we have discovered that four complexes react with dithiocarbamate accelerators most commonly used in latex processing, giving a colored response. Thus, the platinum complexes can be used as colorimetric indicators to detect allergenic dithiocarbamate compounds in latex products. In addition, we describe the synthesis and preliminary characterization of a potential two-electron reagent using a monomeric complex, Pt(4)Cl, and pip 2NNN, where 4 is 1,3-bis(3,5-dimethylpyrazolyl)benzene and (pip 2NNN) is 2,6-bis(piperidylmethyl)pyridine, to give Pt(4)(pip 2NNN) +.