Synthesis and structure of new light-resistant bactericide bis(nitrilotrismethylenephosphonato)diaquatetrasilver monohyd

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Synthesis and Structure of New Light-Resistant Bactericide Bis(nitrilotrismethylenephosphonato)diaquatetrasilver Monohydrate {Ag4[NH(CH2PO3H)3]2(H2O)2} ⋅ H2O N. V. Somova and F. F. Chausovb a

University of Nizhny Novgorod, pr. Gagarina 23, Nizhny Novgorod, 603950 Russia b Udmurt State University,Universitetskaya ul. 1, Izhevsk, 426034, Russia e-mail: [email protected] e-mail: [email protected] Received December 29, 2014

Abstract—A new four-core silver complex {Ag4[NH(CH2PO3H)3]2(H2O)2} ⋅ H2O has been synthesized and investigated. Its crystallographic characteristics are sp. gr. P 1 , Z = 1, a = 7.5806(2) Å, b = 8.4946(2) Å, c = 10.1092(3) Å, α = 81.087(2)°, β = 88.356(2)°, γ = 82.132(2)°. The ligand in the form of zwitterion is hexdentate. The complex is chelating; each silver atom closes an eight-membered cycle Ag–O–P–C–N–C–P–O. Simultaneously, two ligand molecules form six bridge bonds with neighboring formula units. Silver atoms form a polycyclic cluster Ag4O6, the configuration of which is stabilized by coordination and hydrogen bonds. DOI: 10.1134/S1063774516010235

INTRODUCTION

in a bactericidal complex makes it possible to suppress the resistance of some strains to silver. Along with bactericidal properties, some coordination silver compounds exhibit valuable luminescence properties [11, 12]. Organopolyphosphonic acids are promising ligands for Ag(I) due to the large number and steric availability of donor oxygen atoms [13] and, as a consequence, the possibility of various coordinations of transition metal atoms with the formation of both bridge and chelating structures. Nevertheless, the structure of complexes of copper subgroup metals with nitrilo-tris(methylene phosphonic) acid (NTP), N(CH2PO3)3H6, has been studied rather poorly. Complexes of copper with NTP have been synthesized and investigated only recently [14, 15], and, to the best of our knowledge, there are no data on the corresponding silver derivatives. In this paper we describe the synthesis and crystal structure of monohydrate bis[nitrilo-tris (methylene phosphonate)]diaquatetrasilver {Ag4[NH(CH2PO3H)3]2(H2O)2} ⋅ H2O.

Bactericidal properties of silver compounds and dispersed metallic silver, which have been known for a long time, are successfully applied in human and veterinary medicine, as well as in everyday practice [1, 2]. Silver-containing preparations are highly toxic for bacteria and low-toxic for warm-blooded animals and humans [3]. The selective activity of silver for bacteria is explained by its reversible interaction with nucleic acids [4], which leads to the selective inhibition of the metabolism of phosphates in procariotic cells [5]. In addition, silver and its derivatives exhibit fungicidal [6] and viricidal activity; in particular, they are active to human immunodeficiency virus (HIV) [7, 8]. However, the wide application of silver-containing bactericides is limited by the toxicity of water-soluble silver preparations for many water organisms [9]. The application of nanodispersed metallic silver is r