10.1021/jp983507t.s001
Daniel B. Lawson
Daniel B.
Lawson
Roger L. DeKock
Roger L.
DeKock
Geometry and Electronic Structure of Titanacycloalkenes
American Chemical Society
1999
NRT analysis
Vibrational frequencies
TZV
BLYP
carbon atoms
bond
electron delocalization
CTiC plane
ab initio techniques
B 3LYP levels
h 2 TiC 2 H 2
H 2 TiC 2 H 2
MP
RHF
TiC 4 ring
resonance theory
H 2 TiC 4 H 4
LANL 2DZ pseudopotential
Electronic Structure
HTiC 3 H 3
AIM
isovalent cyclobutadiene
HTiC 5 H 5
C 2 v symmetry
1999-02-27 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Geometry_and_Electronic_Structure_of_Titanacycloalkenes/3727395
A number of titanacycloalkenes, H<sub>2</sub>TiC<sub>2</sub>H<sub>2</sub>, HTiC<sub>3</sub>H<sub>3</sub>, H<sub>2</sub>TiC<sub>4</sub>H<sub>4</sub>, and HTiC<sub>5</sub>H<sub>5</sub>, have been studied using ab
initio techniques. Vibrational frequencies were computed at the RHF, MP2, BLYP, and B3LYP levels. Both
a LANL2DZ pseudopotential and an all-electron TZV basis set was used for each method. The electronic
structure of the systems of interest is characterized in terms of natural resonance theory (NRT) and the atoms
in molecules (AIM) analysis. All rings are planar except for titanabenzene, HTiC<sub>5</sub>H<sub>5</sub>. H<sub>2</sub>TiC<sub>2</sub>H<sub>2</sub> has <i>C</i><sub>2</sub><i><sub>v</sub></i>
symmetry and has single Ti−C bonds. HTiC<sub>3</sub>H<sub>3</sub>, unlike the isovalent cyclobutadiene and silacyclobutadiene,
has <i>C</i><sub>2</sub><i><sub>v</sub></i> symmetry and shows significant electron delocalization. In H<sub>2</sub>TiC<sub>4</sub>H<sub>4</sub> the TiC<sub>4</sub> ring is planar with
equivalent single Ti−C bonds and has <i>C</i><sub>2</sub><i><sub>v</sub></i> symmetry. HTiC<sub>5</sub>H<sub>5</sub> has a boat-shaped geometry where the angle
between the CTiC plane and the plane formed by the neighboring four carbon atoms is nearly 90°. AIM
analysis isolates a weak critical point between Ti and the para-C atom, and NRT analysis confirms the weak
bonding interaction.