Catechol and 1,2,4,5-tetrahydroxybenzene functionalized cyclodiphosphazane ligands: synthesis, structural studies, and transition metal complexes

Syntheses of two novel cyclodiphosphazane derivatives appended on catechol and 1,2,4,5-tetrahydroxy benzene, [{(mu-N(Bu-t)P)(2)(C6H4O2)}] (1) and [{((mu-N(Bu-t)P)(2))(2)(mu-C6H2O4)}] (2), are described. Reactions of 1 with copper(I) halides led to the isolation of one-dimensional (1-D) and two-dimensional (2-D) coordination polymers, depending on the reaction conditions, metal-to-ligand ratio and CuX (X = Cl, Br or I) employed. The 1 : 1 reaction between 1 and CuCl yielded a 1-D coordination polymer [{(mu-N(Bu-t)P)(2)(C6H4O2)}{Cu(mu(2)-Cl) (NCCH3)}(2)] n (3) containing [Cu(mu(2)-Cl)](2) rhombus units. Similar reactions of 1 with CuBr and CuI produced rare 1-D coordination polymers [{(mu-N(Bu-t)P)(2)(C6H4O2)}{CuX(NCCH3)}](n) (4, X = Br; 5, X = I) with discrete copper atoms linked by bridging cyclodiphosphazane ligands. However, the reactions of 1 with CuX (X = Cl, Br or I) in 1 : 2 molar ratios afforded 2-D coordination polymers [{(mu-N(Bu-t) P)(2)(C6H4O2)}(2){Cu-4(mu(3)-X)(4)}](n) (6, X = Cl; 7, X = Br and 8, X = I) containing cuboids [Cu-4(mu(3)-X)(4)] with 1 linking such units. Treatment of 1 with [RuCl2(eta(6)-p-cymene)](2), [Rh(COD)Cl](2) and [Pd(eta(3)-C3H5)Cl](2) in 1 : 1 molar ratios produced dinuclear complexes [{(mu-N(Bu-t)P)(2)(C6H4O2)}{RuCl2(eta(6)-p-cymene)}(2)] (9), [{(mu-N(Bu-t) P)(2)(C6H4O2)}{RhCl(COD)}(2)] (10) and [{(mu-N(Bu-t)P)(2)(C6H4O2)}{PdCl(eta(3)-C3H5)}(2)] (11), respectively. The reaction between 1 and [AuCl(SMe2)] in a 1 : 2 ratio yielded a dinuclear complex [{(mu-N(Bu-t)P)(2)(C6H4O2)} {AuCl}(2)] (12). The reactions of 2 with [RuCl2(eta(6)-p-cymene)](2), [Rh(COD)Cl](2) and [Pd(eta(3)-C3H5)Cl](2) in 1 : 2 molar ratios afforded tetranuclear complexes [{((mu-N(Bu-t)P)(2))(2)(mu-C6H2O4)}{RuCl2(eta(6)-p-cymene)}(4)] (13), [{((mu-N(Bu-t)P)(2))(2)(mu-C6H2O4)}{RhCl(COD)}(4)] (14) and [{((mu-N(Bu-t)P)(2))(2)(mu-C6H2O4)}{PdCl(eta(3)-C3H5)}(4)] (15), respectively. The reaction of 2 with [AuCl(SMe2)] also afforded a tetranuclear complex [{((mu-N(Bu-t) P)(2))(2)(mu-C6H2O4)}{AuCl}(4)] (16). In all these complexes, ligands preferred a bridged bidentate mode of coordination. Compounds 3-8 are the rare examples of 1-D and 2-D copper(I) coordination polymers containing cyclodiphosphazane ligands. The crystal structures of 2-8, and 15 were established by X-ray diffraction studies.