Morphological and Structural Characterization of (Pt, Au, and Ag) Nanoparticle/Zn-MOF-74 Composites.

Metallic nanoparticles (NPs) were decorated onto Zn-MOF-74 crystals by photoreducing different metal precursors (Pt, Au, and Ag) using ultraviolet (UV) light in an aqueous solution with different metal concentrations without using additional stabilizers. X-ray diffraction revealed the three-dimensional structural integrity and crystallinity conservation of Zn-MOF-74 crystals during the UV decoration process. Raman spectroscopy showed a minor rearrangement in the structure of the Zn-MOF-74 crystal surface after NP decoration.

Hexamethylenetetramine-tridecanedioic acid (1/1): temperature-induced order-disorder structural phase transitions with phase co-existence.

The cocrystal hexamethylenetetramine-tridecanedioic acid (1/1) (HMT-C13), CHN·CHO, was investigated by single-crystal X-ray diffraction techniques at several temperatures during cooling and heating processes. Our results show the formation of two crystalline phases, separated by a large temperature phase co-existence between 290 and 340 K. Phase I, stable above 341 K, presents an orthorhombic structure described in the space group Bmmb, with one N(CH)·CHO adduct in its asymmetric unit.