Structural studies of aromatic complexes using rotational coherence spectroscopy

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7165024

Joireman, P W

Rotational coherence spectroscopy (RCS), a time-domain variant of high-resolution rotational spectroscopy, has been applied to several one-to-one van der Waals complexes. The primary focus of this study is to obtain rotational constants for each complex from an RCS experiment and then derive structural parameters from them. Each of these complexes contains at least one monomer that exhibits aromatic character. Three different types of interactions, aromatic-aromatic, aromatic-non-aromatic and hydrogen bonding have been investigated. In the first case, the dimers fluorene-benzene, fluorene-toluene, perylene-benzene and perylene-toluene, were studied. In the second, the structurally similar dimers of fluorene-cyclohexane, fluorene-methylcyclohexane, perylene-cyclohexane, and perylene-methylcyclohexane, were studied. The perylene complexes exhibit structures in which the complexing agent is bound between 3.5 [angstrom] to 4.3 [angstrom] above the perylene monomer approximately over the central ring of perylene, and the molecular planes of perylene and the complexing agent are essentially parallel. The fluorene complexes exhibit similar structures. However, for the fluorene-aromatic complexes there are differences. First, the molecular plane of the complexing agent is not stacked directly on top of the fluorene plane, analogous to two neatly stacked sheets of paper, there is a displacement of shear between the two molecular planes. Second, in the case of fluorene-benzene, a noticeable tilt between the molecular planes of the two monomers was observed. The structural results for these van der Waals complexes are compared with structures predicted using empirical atom-atom pair potentials. In the last case, the carbazole-water and carbazole-ammonia complexes, which form N-H[center dot][center dot][center dot]X hydrogen bonds, have been studied using RCS.

• Research Organization: California Univ., Los Angeles, CA (United States)
• OSTI ID: 7165024
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AROMATICS
COMPLEXES
CONDENSED AROMATICS
FLUORENE
HYDROCARBONS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
PERYLENE
VAN DER WAALS FORCES