Synthesis of a highly reactive form of WO2Cl2, its conversion into nanocrystalline mono-hydrated WO3and coordination compounds with tetramethylurea.
A new form of WO2Cl2was obtained by modification of a literature procedure. Both the newly prepared WO2Cl2and the commercial yellow WO2Cl2exhibited an orthorhombic structure (powder X-ray diffraction, P-XRD), and their air exposure at room temperature afforded light green and lemon yellow WO3·H2O (orthorhombic phase), respectively. These materials were characterized by P-XRD, high-resolution transmission electron microscopy (HR-TEM) and scanning transmission electron microscopy (S-TEM). The analyses revealed the nanocrystalline nature of light green WO3·H2O, and the prevalent amorphism of lemon yellow WO3·H2O. The reactions of grey WO2Cl2with one and two equivalents of tetramethylurea (tmu), in CH2Cl2at room temperature, led to the isolation of the trinuclear complex [WO2Cl2(tmu)]3, 1 (45% yield), and the mononuclear one WO2Cl2(tmu)2, 2 (64%), respectively. Compounds 1 and 2 were fully characterized by analytical and spectroscopic methods, single crystal X-ray diffraction (SC-XRD) and DFT calculations.
Università di Venezia Ca' Foscari, Dipartimento di Scienze Molecolari e Nanosistemi, Via Torino 155, I-30170 Mestre, VE, Italy.
Marco
M
Bortoluzzi
Claudio
C
Evangelisti
Fabio
F
Marchetti
Guido
G
Pampaloni
Fabio
F
Piccinelli
Stefano
S
Zacchini