Lawrence Berkeley National Laboratory

The development of heterogeneous materials, catalysts, and semiconductors is often reliant on precise control of self-assembly and crystal packing. Many new materials are initially synthesized as microcrystalline powders, making them incompatible with typical methods of structure determination, such as single-crystal X-ray diffraction. This resultant lack of structural information has made thorough investigation into the effect of metal substitution on crystal structure in metal-organic chalcogenolates (MOChas) challenging. Here, we use small molecule serial femtosecond crystallography (smSFX) to present the structures of four copper n-alkanethiolates: CuSC4, CuSC5, CuSC6, and CuSC7. Divergent patterns of alkyl chain packing are identified from microcrystalline powders via smSFX. An odd-even effect in crystal packing has been identified and attributed to different orientations of symmetry elements in the even- and odd-numbered chains. This results in minute changes in the azimuthal organization of the even-numbered chains and the network of cuprophilic interactions. Additionally, we present a synthesis of crystalline gold n-alkanethiolates to provide the first comparison between three d¹⁰ coinage metals (Cu, Ag, and Au) and their resultant n-alkanethiolates.