(μ-Methylenediphosphonato-κ4 O,O':O'',O''')bis[(ethyl-ene-diamine-κ2 N,N')palladium(II)] tetra-hydrate.

Viktoriya V Dyakonenko,Natalia V Tsaryk,Vasily I Pekhnyo,Ruslan V Lavryk,Alexandra N Kozachkova

doi:10.1107/s2056989018016419

Abstract

The title compound, [Pd2(C2H8N2)2(CH2O6P2)]·4H2O, comprises of a binuclear mol-ecule (point group symmetry 2), with a twofold rotation axis running through the central C atom of the methyl-enedi-phospho-nate (MDP) anion. The PdII atom has a square-planar coordination environment defined by the N atoms of a bidentate ethyl-enedi-amine (en) ligand and two O atoms of the bridging MDP anion. In the crystal structure, metal complexes are arranged in layers parallel (001) and are sandwiched between layers containing disordered water mol-ecules of crystallization. Extensive intra-layer hydrogen bonds of the type N-H⋯O in the metal complex layer and O-H⋯O in the water layer, as well as O-H⋯O hydrogen bonds between the two types of layers, lead to the formation a three-dimensional network structure. The two lattice water mol-ecules are each equally disordered over two positions.

Highlights

Platinum drugs are some of the most important and clinically applied anti-cancer agents
The binuclear [Pd2(en)2(MDP)] complex molecule is uncharged and exhibits point group symmetry 2, with the twofold rotation axis passing through the central C atom of the MDP ligand (Fig. 1)
The PdII atom has a square-planar environment defined by two nitrogen atoms (N1 and N2) of the chelating en ligand and two oxygen atoms (O2 and O3) of the bis-bidentately coordinating MDP ligand that bridges two symmetry-related PdII atoms into the binuclear complex

Summary

Chemical context

Platinum drugs are some of the most important and clinically applied anti-cancer agents. Diphosphonic acids are therapeutic agents for treating osteoporosis and metastatic bone diseases. New complexes designed with a combination of platinum group metals with diphosphonic acid (or derivatives thereof) as bone-targeting groups can improve the chemotherapeutic efficacy in the treatment of bone cancer and can reduce adverse effects. Methylenediphosphonic acid (medronic acid, MDP, H4L) is the smallest bisphosphonate, which accumulates on the sites of osteoid mineralization and can be used in combination with platinum metals to treat cancer and metastatic bone diseases. Platinum–bisphosphonate complexes, including bis{ethylenediamine)platinum(II)}medronate, as novel Pt-prodrugs in the local treatment of bone tumors have been reported (Wani et al, 2016; Iafisco et al, 2009; Palazzo et al, 2007; Iafisco & Margiotta, 2012; Margiotta et al, 2009). We synthesized a new platinum metal complex, viz. [Pd2(C2H8N2)2(CH2O6P2)]Á4H2O or [Pd2(en)2(MDP)]Á4H2O, and report here its molecular and crystal structures

Structural commentary

Supramolecular features

Database survey

Refinement