Combining Fourier transform nuclear quadrupole resonance (FT-NQR) spectroscopy and mass spectrometry (MS) to study the electronic structure of titanocene dichlorides.
A combination of nuclear quadrupole resonance spectroscopy (NQR) and mass spectrometry (MS) has been used to observe trends in electronic structure in three titanocenes: bis(cyclopentadienyl) titanium dichloride (η(5)-C(5)H(5))(2)TiCl(2), bis(pentamethylcyclopentadienyl) titanium dichloride (η(5)-C(5)(CH(3))(5))(2)TiCl(2) and dimethylsilylene-bridged ansa bis(cyclopentadienyl) titanium dichloride Si(CH(3))(2)(η(5)-C(5)H(5))(2)TiCl(2). Using MS, electron ionisation mass spectra of these compounds are presented within the context of the entire homologous series with one to five methyl groups on each cyclopentadienyl ligand. A dedicated NQR spectrometer was constructed for this study with a sensitivity sufficient to precisely determine the NQR resonant frequency of (35)Cl atoms using 3 g samples of these titanocenes. The observed frequencies are thus 11.784, 11.930 and 10.863 MHz at 298 K. The results demonstrate that NQR using a relatively simple apparatus can be used as a sensitive and cost effective probe into the molecular structure of organometallic chlorides, which complements the information inferred from the mass spectra.
J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova, 182 23 Prague, Czech Republic. kubista@jh-inst.cas.cz
Jiří
J
Kubišta
Martin
M
Civiš
Patrik
P
Spaněl
Svatopluk
S
Civiš