Thermal transformations and stability of organometallic materials with electrical and optical properties: the case of polycrystalline cis-[Ir(CO)2Cl(C5H5N)].
In this paper the solid-state transformations under heating of cis-[Ir(CO)2Cl(C5H5N)] are discussed. The complexity of the transformations was revealed by integrating infrared spectroscopy, conventional and bidimensional X-ray diffraction, thermal analysis, and hot stage optical microscopy. During heating anisotropic expansion of the lattice along the Ir-Ir stacking takes place. Then cis-[Ir(CO)2Cl(C5H5N)] undergoes an irreversible solid-solid phase transition to a lattice of higher symmetry followed by a reversible transition into the amorphous phase. Under proper cooling a partial recrystallization takes place. Experiments in the presence of oxygen must be carried out in short time periods to avoid oxidation from Ir(I) to Ir(III).
Bergese
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P
Laboratorio di Strutturistica Chimica, Università di Brescia and INSTM UdR di Brescia, via Branze 38, 25123 Brescia, Italy. paolo.bergese@ing.unibs.it
Bontempi
E
E
Dragonetti
C
C
Roberto
D
D
Ugo
R
R
Colombo
I
I
Depero
L E
LE
D003460:Crystallization; D004583:Electrons; D007495:Iridium / Q000737:chemistry*; D055095:Optics and Photonics; D009942:Organometallic Compounds / Q000737:chemistry*; D013696:Temperature
D009942:Organometallic Compounds; C521421:dicarbonylchloro(pyridine)iridium(I); D007495:Iridium