Platinum complexes with binding affinity for the estrogen receptor.

A number of (1,2-diaminoethane)dichloroplatinum(II) complexes, linked to dihydroxy-2-phenylindole by spacer groups of varying lengths, were synthesized and studied for their binding affinities for the calf uterine estrogen receptor. Best binding conditions were provided by the n-hexyl and the p-xylene group as spacer with RBA values of 6.5 (16c) and 4.4 (17c), respectively (17 beta-estradiol: RBA = 100). These values are only slightly lower than those of the corresponding diaminoethane ligands.