No abstract

Careful control of the temperature and duration of the reaction between titanium tert-butoxide and acetic acid leads to the formation of new polyoxotitanate clusters with 14, 18, and 28 Ti atoms. They are considered intermediates in the growth of Ti/O nanoclusters of increasing size. The Ti(28) cluster is the largest crystallized to date. UV/vis spectroscopy on this cluster reveals that the optical band gap is blue-shifted with respect to a cluster containing only 17 titanium atoms indicating that the optical properties are more heavily influenced by the internal structure of the particle than its size.

We investigate the out-of-equilibrium switching dynamics of a molecular Fe(III) spin-crossover solid triggered by a femtosecond laser flash. The time-resolved x-ray diffraction and optical results show that the dynamics span from subpicosecond local photoswitching followed by volume expansion (nanosecond) and thermal switching (microsecond). We present a physical picture of the consecutive steps in the photoswitching of molecular materials.