Quaternization and oxidation reactions of cyclodiphosphazane derivatives and their copper(I) and gold(I) complexes.

The reactions of cyclodiphosphazane derivatives cis-{(t)BuN(H)P(μ-N(t)Bu)2PN(H)(t)Bu} (1), cis-{MeN(C4H8N)P(μ-N(t)Bu)2P(NC4H8Me)} (2) and {(Me2NCH2CH2O)P(μ-N(t)Bu)2P(OCH2CH2NMe2)} (3) with methyl iodide and methyl triflate and their subsequent reactions with elemental sulfur and selenium are reported. Interestingly, the reactions of 1-3 with an excess of methyl iodide resulted in quaternising only one phosphorus atom in cis-[{(t)BuNHP(μ-N(t)Bu)2P(CH3)NH(t)Bu}](I) (4), two exocyclic nitrogen atoms and one of the phosphorus atoms in cis-{(Me2NC4H8N)P(μ-N(t)Bu)2P(CH3)(NC4H8NMe2)}](I)3 (7) and only two exocyclic nitrogen atoms in cis-[{(Me3NCH2CH2O)P(μ-N(t)Bu)2P(OCH2CH2NMe3)}](I)2 (8). The reaction of 1 with one equiv. of methyl triflate produced cis-[{(t)BuN(H)P(μ-N(t)Bu)2P(CH3)N(H)(t)Bu}]OTf (5), whereas the same reaction in a 1 : 2 molar ratio afforded cis-{(t)BuN(H)P(CH3)(μ-N(t)Bu)2P(CH3)N(H)(t)Bu}(OTf)2 (6). Compounds 4 and 5 showed poor solubility in water, whereas 7 and 8 were high melting crystalline solids with moderate to good water solubility. Treatment of 4 with either elemental sulfur or selenium gave both cis- and trans-chalcogenide derivatives. Similar reactions of 7 and 8 produced both mono- and bischalcogenides. Reactions between 4 or 7 and CuI yielded dinuclear complexes, cis-[{Cu2(μ-I)3((t)BuN(H)P)(μ-N(t)Bu)2(P(CH3)N(H)(t)Bu)]2}(I)] (15) and cis-[{Cu2(μ-I)3[(Me2NC4H8N)P(μ-N(t)Bu)2P(CH3)(NC4H8NMe2)]2}(I)5] (16), while the reaction of 8 with CuI produced a coordination polymer [{Cu2(μ-I)3(μ-N(t)BuP)2(OCH2CH2NMe3)2}I]∞ (17), containing triiodo-bridged [Cu2(μ-I)3] linkers. The molecular structures of several of these compounds were confirmed by single crystal X-ray diffraction studies. The Cu(I)···Cu(I) distance of 2.55 Å in 15 is quite short and is the same as that found in copper metal and also in complexes containing [Cu2(μ-I)3] linkers. All the metal complexes exhibit strong intra-, inter- or both intra- and inter-molecular hydrogen bonding interactions.