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Volume 3, Issue 2 (Suppl) Ind Chem
ISSN: 2469-9764, ICO an open access journa Industrial Chemistry 2017
May 22-23, 2017
Page 46
Notes:
conferenceseries.com
May 22-23, 2017 Las Vegas, USA
2nd World Conference on
Industrial Chemistry and Water Treatment
Unusual phenomena in helix-sense-selective polymerization and its product
In 1993, we accidentally discovered the first example of an asymmetric-induced polymerization (AIP) of chiral substituted
acetylene, during our study on optical resolution membranes. Since poly substituted acetylenes have no asymmetric carbons,
the optical activity is caused by the one-handed helical conformation. Therefore, the optical activity is often not static but
dynamic. In 2003, we reported the first helix-sense-selective polymerization (HSSP) of an achiral substituted acetylene by
using a chiral catalytic system consisting of chiral phenyl ethylamine (PEA) and a rhodium dimer complex ([Rh (nbd) Cl]2,
nbd=2,5-norbornadiene). The achiral monomer had two hydroxymethyl groups and a relatively hydrophobic substituent and
the one-handed helicity of the resulting polymer was statically maintained by intramolecular hydrogen bonds in nonpolar
solvents. After the discovery, we found some new monomers suitable for the HSSP reaction and have tried to control the
polymerization. During these studies, some unusual phenomena were also found to occur in the HSSP process. We found
that the HSSP of achiral phenylacetylenes having two hydroxy groups was catalyzed by the chiral polymers prepared by the
HSSP of the same or similar achiral phenylacetylenes instead of using the chiral cocatalyst like PEA (Self-HSSP). In addition,
it shows the possibility of in-situ self-catalyzed HSSP where the HSSP products formed during the HSSP functioned in-situ
as a chiral cocatalyst for the HSSP of the same monomer (In-situ self-HSSP). In addition to the discovery of self-HSSP, other
several unusual phenomena were observed in the HSSP of RDHPA. For example, the sense of the helicity of the polymers
prepared by HSSP was controlled by changing non-chiral conditions such as the molar ratio of the chiral cocatalyst to the
rhodium complex (Reversal HSSP). That may be caused by formation of different chiral rhodium species depending on the
ratio. In addition, HSSP was also realized without any chiral source (Spontaneous HSSP). It may result from the formation
of a chiral supramolecular compound of the monomer. Since the polymer resulting from HSSP adopts very tight cis-cisoidal
conformation and therefore a rigid rod structure, which is not seen in any other poly (substituted acetylenes), it shows many
unusual and interesting properties, including unique types of reactivity. For example, in 2013, we reported highly selective
photo aromatization (SCAT) of the very tight cis-cisoidal polymer prepared by HSSP.
Biography
Toshiki Aoki has received his Doctorate degree (1987) on synthesis and oxygen permeability of graft copolymers from oligosiloxane macromonomers in Department
of Applied Chemistry at Nagoya University, Japan. He has joined Fluorine Chemistry Division at Government Industrial Research Institute, Nagoya in 1987-1989.
He has then moved to Department of Applied Chemistry at Niigata University in 1989. He has worked at Niigata University as an Assistant Professor (1989), Asso-
ciate Professor (1995) and Full Professor (2000). He has worked as a Visiting Scientist at University of Southern California from 1998-1999. His research interest
covers synthesis of functional polymers, including synthesis of new chiral polymers for permselective membranes. His recent interest is in synthesis and application
of two-dimensional polymers using HSSP and SCAT reactions.
Toshiki Aoki
Niigata University, Japan
Toshiki Aoki, Ind Chem 2017, 3:2 (Suppl)