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Platinum(II) Complexes with the Diethyl Aminomethylphosphonate Ligand (amp): Characterization, Properties, and Unusual Solution Behavior
Author(s) -
Cornacchia Daniele,
Cerasino Leonardo,
Pacifico Concetta,
Natile Giovanni
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200701245
Subject(s) - chemistry , ligand (biochemistry) , phosphonate , denticity , chelation , stereochemistry , cisplatin , adduct , neurotoxicity , medicinal chemistry , organic chemistry , crystal structure , biochemistry , toxicity , chemotherapy , receptor , medicine , surgery
Cisplatin is one of the most widely prescribed drugs for the treatment of solid tumors, even though its pharmacological potential is often limited by side effects (nephrotoxicity, neurotoxicity, alopecia) and a limited spectrum of activity. Overcoming these limitations is one of the most chased goals by researchers in the field of medicinal chemistry. Since phosphonates have a great selectivity for bone tissues, we have extended a previous study on a platinum(II) complex with a diethyl [(methylsulfinyl)methyl]phosphonate (smp) ligand, [PtCl 2 ( S,O ‐smp)], to another phosphonate ester ligand, diethyl aminomethylphosphonate (amp). Further interest in this investigation was generated by the observation that [PtCl 2 ( S , O ‐smp)] was capable of inhibiting matrix metalloproteinases (MMPs), which also play a role in tumor growth. The interaction of the amp ligand with the tetrachloroplatinate(II) anion resulted in the production of the mono‐ and bis(amp) adducts in which the ligand acts as a monodentate N ‐coordinated species; however, no stable species with the chelating ligand could be isolated. A rationale for the different chelating abilities of amp and smp is offered. A solution of cis ‐[PtCl 2 ( N ‐amp) 2 ] in organic solvents is very stable if kept in the dark; if it is exposed to light, it undergoes a ready and clean cis / trans isomerization, affording the trans ‐[PtCl 2 ( N ‐amp) 2 ] complex. The compounds have been characterized by means of spectroscopic techniques ( 1 H, 31 P, and 195 Pt NMR), ESI‐MS, and elemental analysis. In the case of trans ‐[PtCl 2 ( N ‐amp) 2 ], the X‐ray structure has revealed a peculiar in‐plane orientation of the amp ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)