A cyclo-P6 Ligand Complex for the Formation of Planar 2D Layers

The all-phosphorus analogue of benzene, stabilized as middle deck in triple-decker complexes, is a promising building block for the formation of graphene-like sheet structures. The reaction of [(CpMo)(2)(,(6):(6)-P-6)] (1) with CuX (X=Br, I) leads to self-assembly into unprecedented 2D networks of [{(CpMo)(2)P-6}(CuBr)(4)](n) (2) and [{(CpMo)(2)P-6}(CuI)(2)](n) (3). X-ray structural analyses show a unique deformation of the previously planar cyclo-P-6 ligand. This includes bending of one P atom in an envelope conformation as well as a bisallylic distortion. Despite this, 2 and 3 form planar layers. Both polymers were furthermore analyzed by P-31{H-1} magic angle spinning (MAS) NMR spectroscopy, revealing signals corresponding to six non-equivalent phosphorus sites. A peak assignment is achieved by 2D correlation spectra as well as by DFT chemical shift computations.