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Carbonyldinitrosyltris(fluorosulfato)tungstate(II) and ‐Molybdate(II) Anions: Synthesis, Spectroscopy, and Density Functional Theory Calculations
Author(s) -
Xu Qiang,
Tsumori Nobuko,
Jiang Ling,
Kondo Masanobu,
Arakawa Ryuichi
Publication year - 2007
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200600430
Subject(s) - chemistry , tungstate , density functional theory , molybdate , crystallography , ligand (biochemistry) , nucleophile , moiety , mulliken population analysis , raman spectroscopy , singlet state , population , coordination sphere , inorganic chemistry , stereochemistry , computational chemistry , crystal structure , excited state , catalysis , biochemistry , physics , receptor , demography , sociology , nuclear physics , optics
Carbonyldinitrosyltris(fluorosulfato)tungstate(II) and ‐molybdate‐(II) anions, [ fac ‐M(CO)(NO) 2 (SO 3 F) 3 ] − (M=W, Mo), which are novel weakly coordinating anions that contain a metal carbonyl/nitrosyl moiety, have been generated in fluorosulfonic acid and completely characterized by multinuclear NMR, IR, and Raman spectroscopy as well as ESI mass spectrometry. ESI MS measurements performed for the first time on a superacidic solution system unambiguously reveal the formation of the monoanionic, mononuclear W and Mo complexes formulated as [M(CO)(NO) 2 (SO 3 F) 3 ] − (M=W, Mo). Multinuclear NMR spectroscopic studies at natural abundance and 13 C and 15 N enrichment clearly indicate the presence of one CO ligand, two equivalent NO ligands, and two types of nonequivalent SO 3 F − groups in a 2:1 ratio. The IR and Raman spectra reveal that the two equivalent NO ligands have a cis conformation, thus indicating a fac structure. Density functional calculations at the B3LYP level of theory predict that these anions have a singlet ground state ( 1 A′) with a C s symmetry along with C–O and N–O vibrational frequencies that are in agreement with the experimental observations. Mulliken population analysis shows that the monovalent negative charge is dispersed on the bulky sphere, the surface of which is covered by all the negatively charged O and F atoms with charge densities much lower than SO 3 F − , suggesting that [ fac ‐M(CO)(NO) 2 (SO 3 F) 3 ] − (M=W, Mo) are weakly nucleophilic and poorly coordinating anions.