CIS-DIAMINEDICHLOROPLATINUM(II) COMPLEXES REVERSIBLY LINKED INTO THE MAIN-CHAIN OF WATER-SOLUBLE POLYAMIDES

As a follow-up study to previous work involving the platination of pol yamide carriers through metal chelation by side group-incorporated eth ylenediamine ligands, the present investigation is concerned with the synthesis of platinum-containing polymers in which the metal-coordinat ing ethylenediamine segments are components of the main chain. Two chl oro groups in cia geometry are attached to each Pt atom as additional ligands, complementing a square-planar cis-diaminedichloroplatinum(Il) complex system. The water-soluble polymeric carriers are synthesized by Michael-type addition polymerization, interfacial polymerization, a nd high-temperature solution polycondensation techniques and are crude ly fractionated by stepwise aqueous dialysis, ultimately in tubing wit h a molecular mass cutoff of 25,000. Carrier platination is brought ab out by treatment with tetrachloroplatinate(II) anion in aqueous soluti on, care being taken to exercise strict control of reaction variables and workup conditions in an effort to restrict platination to the give n ligands and avoid metal aquation or hydroxylation. The platinum conj ugates, with Pt contents ranging from about 11 to 23% by mass, are com pletely soluble in aqueous media when freshly prepared, although long- term storage at room temperature in the solid state is conducive to gr adual loss of solubility. The conjugates are of interest as carcinosta tic agents.