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A. V. Pomogaeva and A. Y. Timoshkin
It was found that the closer the In atoms are located to the NH/H 3 -capped end,
the greater is the reduction of the energy gap. The closer the Al atoms are located to
the NH/H 3 -capped end, the bigger is the HOMO-LUMO difference.
The importance of electrostatic interaction in open rods has been noticed in
early study [167]. Dipole moments μ of studied compounds are given in Table 6.4.
The direction of the vector is from the GaR/R 3 -capped end of the oligomer to the
NH/H 3 -capped end. There is almost linear dependence of the dipole moments on
the position of substituted rings for open oligomers. Replacement of Ga atoms by
Al or In atoms in the middle rings of the open oligomer has very minor effect on the
dipole moment. For closed oligomers, the position of the substituent in the vicinity
of the N-capped end plays a predominant role in the value of the dipole moment.
Dipole moments of the open oligomers are more than an order of magnitude larger
than that of closed ones. Values of dipole moments for closed oligomers are 2.66,
1.78, and 1.50 D for Al, Ga, and In, respectively. For open oligomers, respective
values are 14.75, 14.45, and 14.07 D. However, there is no simple linear correlation
between the value of dipole moment and the decrease of the HOMO-LUMO gap
energy.
The dependences of energies of HOMO, LUMO, and energy gap values from the
number of the Al/In atoms in mixed metal oligomers are shown in Fig. 6.17. N is
a number of Ga atoms substituted by Al (shown by black marks) or In (shown by
empty marks) atoms. The leftmost side of the figures (N = 0) corresponds to the
binary [CH 3 GaNH] 10 (triangles) and (CH 3 ) 3 [CH 3 GaNH] 9 H 3 (circles) compounds.
Gallium atoms are one by one substituted by Al or In atoms, starting from the
capping CH 3 Ga group of the closed oligomer and followed by the gallium atoms
Fig. 6.17 The HOMO-LUMO gap energy (a), energies of HOMO (b), energies of LUMO (c) of
closed (triangles) and open (circles) mixed metal oligomers. N is a number of Ga atoms, substituted
by Al (black markers) or In (empty markers) atoms. Lines drawn are to guide the eye only. (Adapted
by permission from Springer Nature: Springer [56], COPYRIGHT (2014))
A. V. Pomogaeva and A. Y. Timoshkin
It was found that the closer the In atoms are located to the NH/H 3 -capped end,
the greater is the reduction of the energy gap. The closer the Al atoms are located to
the NH/H 3 -capped end, the bigger is the HOMO-LUMO difference.
The importance of electrostatic interaction in open rods has been noticed in
early study [167]. Dipole moments μ of studied compounds are given in Table 6.4.
The direction of the vector is from the GaR/R 3 -capped end of the oligomer to the
NH/H 3 -capped end. There is almost linear dependence of the dipole moments on
the position of substituted rings for open oligomers. Replacement of Ga atoms by
Al or In atoms in the middle rings of the open oligomer has very minor effect on the
dipole moment. For closed oligomers, the position of the substituent in the vicinity
of the N-capped end plays a predominant role in the value of the dipole moment.
Dipole moments of the open oligomers are more than an order of magnitude larger
than that of closed ones. Values of dipole moments for closed oligomers are 2.66,
1.78, and 1.50 D for Al, Ga, and In, respectively. For open oligomers, respective
values are 14.75, 14.45, and 14.07 D. However, there is no simple linear correlation
between the value of dipole moment and the decrease of the HOMO-LUMO gap
energy.
The dependences of energies of HOMO, LUMO, and energy gap values from the
number of the Al/In atoms in mixed metal oligomers are shown in Fig. 6.17. N is
a number of Ga atoms substituted by Al (shown by black marks) or In (shown by
empty marks) atoms. The leftmost side of the figures (N = 0) corresponds to the
binary [CH 3 GaNH] 10 (triangles) and (CH 3 ) 3 [CH 3 GaNH] 9 H 3 (circles) compounds.
Gallium atoms are one by one substituted by Al or In atoms, starting from the
capping CH 3 Ga group of the closed oligomer and followed by the gallium atoms
Fig. 6.17 The HOMO-LUMO gap energy (a), energies of HOMO (b), energies of LUMO (c) of
closed (triangles) and open (circles) mixed metal oligomers. N is a number of Ga atoms, substituted
by Al (black markers) or In (empty markers) atoms. Lines drawn are to guide the eye only. (Adapted
by permission from Springer Nature: Springer [56], COPYRIGHT (2014))