Niobium oxochlorides in the gas phase: Quantum chemical calculations of the structure and relative stability of isomers

• Published in: Russian journal of inorganic chemistry 2013, Vol.58 (1), p.38-45
• Main Authors: Il’in, E. G., Yarzhemskii, V. G., Parshakov, A. S., Buryak, A. K.
• Format: Article
• Language: English
• Subjects: Anions; Chemistry; Chemistry and Materials Science; Gas phases; Inorganic Chemistry; Isomers; Lasers; Mathematical analysis; Niobium; Quantum chemistry; Stability; Theoretical Inorganic Chemistry
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023613010087

The gas-phase niobium oxochloride anions that result by the interaction between the finely dispersed stereoselective acetylene cyclotrimerization catalyst NbCl 2 (C n H n ) ( n = 10–12) and atmospheric oxygen and moisture have been characterized by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry. From the relative intensities of mass spectrometric lines, it has been deduced that, among the various niobium oxochloride species passing into the gas phase under the action of laser radiation, the most abundant monomer ion is NbO 2 Cl 2 − , the most abundant dimers are Nb 2 O 4 Cl 3 − and Nb 2 O 3 Cl 5 − , the most abundant trimer is Nb 3 O 6 Cl 5 − , and the most abundant tetramer is Nb 4 O 8 Cl 5 − . The gas phase also contains low concentrations of fragments corresponding to the pentanuclear anion Nb 3 O 11 Cl 4 − and the hexanuclear anion Nb 6 O 15 Cl 2 − . The geometric parameters and total energy of the stable isomers of the dinuclear and polynuclear niobium oxochloride anions existing in the gas phase has been calculated by quantum chemical methods, and their relative thermodynamic stabilities have been determined for different metal core configurations and different arrangements of oxygen and chlorine ions. The stereochemistry of the niobium oxochlorides is discussed.