The preparation of [Pt(tmdz)Cl2] (tmdz
= 5,5,7-trimethyl-1,4-diazacycloheptane) is described. The crystal
structure has been determined by X-ray diffraction methods and refined to an
R value of 0·048 (764F).
The crystals are triclinic, space group P
-1, a 8·023(2),
b 10·874(4), c
14·207(3) Å, α 95·34(3), β 94·96(2),
γ 94·97(3)°. N.m.r. studies and molecular mechanics methods
show that only one diastereomer of the complex—that observed in the
crystal structure—is energetically accessible. In total DNA binding
studies, [Pt(tmdz)Cl2] binds less effectively
and at a lower rate than cisplatin. The complex reacts
with dG and d(GpG) to form a variety of isomeric products, as indicated by
h.p.l.c. analysis.