No abstract

No abstract

The reaction of the (2-pyridylmethylamino)-substituted cyclotriphosphazene N3P3(0C6H5)5(NHCH2(C5H4N)-2) (1) with copper(I1) nitrate, platinum(I1) chloride, and cobalt(I1) nitrate yields the stable complexes [Cu(N03), .( 1 ) 4 (la), [PtQ . (l)] ( l b ) , [CO(NO,)~ . ( l ) ] ( l c ) . The X-ray crystallographic studies of these metal complexes revealed the different coordination behavior of the multifunctional ligand.Since the last decades the interest in polymers which form macromolecular metal complexes has been increasing significantly because of the wide range of possible applications for these materials such as ion exchange resins, catalysts, ionic conductors, and carriers or depots for chemotherapeutic For these applications not only the knowledge of the structures of the metal centers but also the physical properties of the polymeric complexes are important for fundamental mechanistical reason^[^^']. Small molecular modelling offers the opportunity to gain important information about the coordination behavior of the functional sites in macromolecules. This method is well established in phosphazene chemistry [2]. Cyclic phosphazene trimers are, besides their importance in the fundamental research of this class of compounds, indicators for the structural and chemical behavior of analogous macromolecules. Especially the coordination behavior of cyclotriphosphazenes can be studied by X-ray crystallography.In the past, different side groups which interact with transition metals were described. Previous choices of exocyclic coordination groups include, for example, phosphanes, acetylenic units, or aryl g r o u p~ [~~~] .These groups are bound to the metal by P-or n-donor coordination.Another type of exocyclic side groups are N-donor groups such as pyrazolyl or dimethylamino groups. This kind of phosphazene contains two possible coordination sites which can interact with transition metals: (a) The Ndonor side group reacts preferably, when electron-withdrawing groups such as pyrazolyl or imidazolyl are combined with phenyl, phenoxy, or trifluoroethoxy Pyridine-substituted phosphazenes are rare, mainly because reactions of chlorinated phosphazenes with pyridine derivatives are known to form cationic adducts which decompose rapidly when water, even in traces, is present in the reaction rnixt~re[~~~'*]. Studies of the complex formation of these phosphazene derivatives are hardly known, and no molecular structures of metal complexes have been published so far [19~20].We recently described the synthesis of several pyridylalkylamino-substituted cyclo-and polyphosphazenes[21 -231. 2-(Aminomethy1)pyridine is known to react with transition metal ions as a bidentate chelating ligand1241. Once attached to the phosphazene, the three PN nitrogen atoms might additionally participate in complex formation although the possibility of metal interactions at these sites is quite low when cosubstituents lower their basicity.Our latest experiments revealed that the new phosphazene-based N-donor ligand shows a very interesting coordin...

Several small molecule cyclotriphosphazenes and high polymeric poly(organophosphazenes) with methylthio groups (CH3SR) have been synthesized: [NP(OCH2CH2SCH3)2]n (n = 3, 1; n = 15,000, 5); [NP(OCH2CH2CH2CH2SCH3)2]n (n = 3, 2; n = 15,000, 6); [NP(OCH2CH2CH(SCH3)CH2CH2CH3)2]n (n = 3, 3; n = 15,000, 7); and [NP(OCH2C6H4SCH3)2]n (n = 3, 4; n = 15,000, 8). Both series of compounds possess multiple thioether coordination sites for potential binding to metals. The methylthioethoxide substituent readily oxidizes to the sulfoxide derivatives in the presence of peroxides. All the phosphazenes were characterized by 1H‐, 13C‐, and 31P‐NMR spectroscopy and elemental analysis, and the small molecule cyclotriphosphazenes were examined by mass spectrometry. Gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) were also employed to characterize the polymers. Metal complexation and extraction capabilities of both the small molecule and polymeric systems are described. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 650–661, 2000