A Theoretical Study For Anticancer Properties Of Trans Platinum Complexes Containing Pyridine Ligand(s)

A series of transplatin analogues with pyridine ligand(s) are studied here using B3LYP-DFT method. The hydrolysis processes of trans-[PtCl₂(ipa)(3-pic)] shows the barrier heights and the endothermicity are both increased when attacking/released ligands are included into the reactant/product complexes. Addition of the bulk solvation increases the barrier heights for both models wherease decreases the reaction energies. The barrier height of the second hydrolysis is always higher than the first step. Barrier heights of the first substitution with DNA are lower than those of cisplatin except the platination of adenine by Pt-diaqua. The inter-strand cross link in the second substitutions is preferred over intra-strand and guanine is preferred over adenine. The second substituon with guanine is more preferred than cisplatin. The tc reaction alignment reveals trans-geometric reactant complex can give rise to cis-geometric product complex in addition to the trans-geometric product complex, and tc alignment is both kinetically and thermodynamically comparable to tt alignment.Barrier heights for the first substitution of trans-[PtCl₂(NH₃)(2-pic)] with guanine are preferred over cisplatin. The inter-strand cross link is more preferred in the second substitution. The first substitutions of trans-[PtCl₂(NH₃)(4-pic)] with DNA is preferred over cisplatin when chloroaqua complex is employed. The inter-strand cross link is more preferred in the second substitution.Both the first and second substitutions of trans-[PtCl₂(NH₃)(pyridine)] with DNA are preferred over those of cisplatin. The first substitutions of trans-[PtCl₂(pyridine)₂] with DNA are preferred over cisplatin and the second substituons are preferred over cisplatin except the interstrand cross link of Pt with guanine. Barrier heights relative to protein residues containing N-atom are lower than purines.