Copper complexes with 1,10-phenanthrolines tethered to a cyclotriphosphazene platform

The synthesis of two ligands, L1 and L2, each containing two 2-oxy-1,10-phenanthroline moieties attached to the same phosphorus atom of a substituted cyclotriphosphazene ring via an oxy-bridge, but differing in substitution on the biphenyl capping groups, is described. The single-crystal X-ray structure of L1 · 2CH2Cl2 shows an ordered structure in the lattice with channels, containing dichloromethane molecules, running parallel to the a-axis. The reactions of L1 and L2 with [Cu(MeCN)4](PF6) afford the dimetallic copper(I) derivatives, [(CuL1)2] (PF6)2 · CH2Cl2 and [(CuL2)2](PF6)2. The single-crystal X-ray structure of the former complex shows that the L1 ligands of the cation [(CuL1)2]2+ act as a bridges coordinating to the two copper(I) centres in a helical fashion. The copper atoms have distorted tetrahedral geometries with the interligand dihedral angle being 85°. With copper(II) chloride and copper(II) perchlorate, the monomeric copper(II) complexes, [CuL1Cl]Cl · 2CH2Cl2, [CuL2Cl]Cl · CH2Cl2, [CuL1(OMe)]PF6 · 2H2O, [CuL2(OMe)]PF6 · 2H2O, [CuL1(OH2)](ClO4)2 and [CuL2(OH2)](ClO4)2 · H2O are obtained. The single-crystal X-ray structure of [CuL1Cl]Cl · 2CH2Cl2 shows the copper to be in a square-base pyramidal distorted trigonal-bipyramidal (SBPDTB) environment (τ = 0.57) with L1 acting as a κ4N donor, coordinating via the four nitrogen atoms of the two tethered 1,10-phenanthrolines. In CH3CN, this complex undergoes hydrolysis via the presence of adventitious water losing one oxyphenanthroline arm to form the centrosymmetric dimetallic species, [(CuL3Cl)2] · 4CH3CN · 3H2O (L3 = [N3P3(biph)2(ophen)O]− where biph = 2,2′-dioxybiphenyl and O replaces an oxyphenanthroline and is attached to the phosphorus of the phosphazene ring). The two monomeric units, which are linked by bridging chlorine atoms, have a distorted square-based pyramidal geometry about the copper with the basal plane made by the ‘ON2Cl’ ligand set. Spectroscopic (mass spectral, electronic and ESR) and magnetic moment data for the complexes are discussed.

The reaction of copper salts with 2-oxy-1,10-phenanthroline moieties tethered to a cyclotriphosphazene ring affords dimetallic copper(I) complexes with the ligand coordinating to two metal centres in a helical fashion whereas the copper(II) complexes are five-coordinate monomeric species.Figure optionsDownload as PowerPoint slide