Mixed-Metal\nAlloying in Hybrid Bronzes

We show that substitutional alloying\nduring the aqueous self-assembly\nof layered organic-templated metal oxides produces single-phase mixed-metal\nhybrids. Single-crystal X-ray diffraction, bulk elemental analyses,\nand vibrational and electronic spectroscopies corroborate a solid\nsolution of Mo and W atoms at lattice sites within the two-dimensional\nmetal oxide layers. Mild postsynthetic reduction then introduces relatively\ndelocalized electrons to afford mixed-metal hybrid bronzes. To our\nknowledge, this represents the first demonstration of mixed-metal\nalloying in a hybrid metal oxide and a rare example of solid-solution\nformation at low temperature. We show this approach yields mixed-metal\ncongeners with optical band gaps over 130 meV smaller than those of\nsingle-metal analogs, while achieving activation energies (<i>E</i><sub>a</sub>) of conduction as low as 78.4(2) meV. Further,\nmetal substitution appears to tune collective electronic phenomena\nby suppressing the non-Arrhenius behavior observed for Mo-based hybrids.\nThis work considerably expands the nascent hybrid bronze platform\nto help address energy-related challenges and fundamental solid-state\nphysical questions.