Molecular ordering by halide–halide interactions in dimolybdenum p-halobenzoates

•Synthesis of MM quadruply bonded complexes supported by halobenzoates.•Solid state structures contains halogen–halogen interactions were found.•Halogen effects on the 1MLCT and 3δδ∗ excited states were examined.

A series of compounds of the form Mo2(O2C-C6H4-X)4, 1-X, and trans-Mo2(TiPB)2(O2C-C6H4-X)2, 2-X, have been prepared where X = F, Cl, Br, and I and TiPB = 2,4,6-triisopropylbenzoate. The compounds 1-X (X = F, Cl) and 2-X (X = F, Cl, Br, and I) have been structurally characterized by single crystal X-ray crystallography, some of which are shown to form extended chains in the solid state due to the formation of halide–halide intermolecular interactions. Both families of compounds have been examined by electronic absorption and emission spectroscopy and the lifetimes of the singlet and triplet lifetimes have been determined. S1 lifetimes are ∼5–8 ps and T1 lifetimes are ∼50–80 μs. The heavy atom halogen appears to have little effect on the S1 lifetimes.

Graphical abstractThe structural and photophysical properties of dimolybdenum quadruply bonded complexes supported by halobenzoate ligands were investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide