Metal-Organic Frameworks with Zero and Low-Valent Metal Nodes Connected by Tetratopic Phosphine Ligands.

Metal-organic frameworks (MOFs) constructed with M 0 nodes are attractive targets due to the reactivity of these low-valent metals, but examples of these MOFs remain exceedingly rare. The rational design of three-dimensional MOFs with Pd 0 and Pt 0 nodes using tetratopic phosphine ligands is reported. Five new MOFs have been synthesized by systematic variation of the phosphine ligands and metal precursors employed, and these represent the first examples of MOFs constructed using phosphine-metal bonds as the sole structural component. The MOFs display solid-state luminescence, with emission maxima that are significantly red-shifted compared to Pd(PPh 3 ) 4 . In addition, a Rh I low-valent coordination solid based on the same linker design is reported, which displays solid-state luminescence that is not observed for the molecular analogue.