Merocyanine dyes Synthesis, properties, application

1
Merocyanine dyesSynthesis, properties,
application
m
Eugenij Poronik
2
Introduction
Brookers merocyanine
J Am Chem Soc 73 (1951) 5326
Merocyanine 540

• Merocyanine dyes are considered as a
  superposition of neutral (I) and zwitterionic
  (III) forms.
• There is an ideal state, so-called cyanine
  limit, which relates to equal contributions of
  the polyene-type and the zwitterionic resonance
  structures.
• Merocyanines in the cyanine limit are also dyes
  with most favorable absorption properties, that
  is, intense absorption bands at the longest
  possible wavelength for a given polymethine
  chain, and they possess enhanced thermal and
  photochemical stability owing to equalized bond
  orders

3
Synthesis
Simple Merocyanines (n 0)
87
J Am Chem Soc 73 (1951) 5326
50
Bull Korean Chem Soc 24 (2003) 569
Zeromethine merocyanines (n 0) are commonly
prepared by the reaction of nitrogen heterocycles
containing a leaving group with active methylene
bases.
4
J Chem Soc, Perkin Trans 2 (1997) 1055
Tetr. Lett 39 (1998) 1763
5
Merocarbocyanines (n 1)
Russ Chem Bull, Int Ed 54 (2005) 2417
Dyes Pigm 60 (2004) 215 Dyes Pigm 58 (2003) 83
J Mater Chem 9 (1999) 2991
The classical route for the synthesis of
merocarbocyanine dyes is a reaction of
heterocyclic enamines or corresponding salts with
hydroxybenzaldehydes or their heterocyclic
analogs.
6
Dyes Pigm 58 (2003) 83
The capability of merocyanines to produce salts
is used for their isolation
7
Using of aldehyde analogous
A versatile method for the preparation of
merocyanine dyes involves the treatment of
methyl-substituted quaternary salts of nitrogen
heterocycles with anilinomethylene derivatives of
heterocyclic ketones.
8
Acetanilidomethylene-substituted heterocycles are
useful, versatile synthones, and they have been
extensively used for the preparation of
merocyanine dyes
9
Dimethylaminomethylene derivatives prepared by
treatment of carbo and heterocyclic ketones with
DMF-DMA or with DMF in acetic anhydride have been
used for the synthesis of various merocyanine dyes
10
Tetr. Lett. 42 (2001) 6129
This reaction is suitable for the preparation of
symmetrical merocyanines (ketocyanines),
difunctionalized ketones are condensed with two
equivalents of quaternary salt
Russ Chem Bull 45 (1996) 164
11
From w-aldehydes
Org Lett 5 (2003) 3143 Angew Chem Int Ed 36
(1997) 2765
The condensation of w-aldehydes with active
methylene compounds in in the absence of the base
leads to merocyanines in moderate yields
J Am Chem Soc 121 (1999) 8146
Aza derivatives of w-aldehydes are the most
utilized starting materials for the preparation
of merocyanine dyes since the first merocyanine
syntheses
12
Synthesis (1999) 2103 Angew Chem Int Ed 38 (1999)
1649

• A versatile one-pot synthesis of merocyanines
  based on multi-step reaction of nitrogen
  heterocycles with active methylene compounds and
  DMF in acetic anhydride 45, 59.
• The process is uninfluenced by impurities in
  starting compounds, including water, and can be
  used in combinatorial synthesis.

13
51
Tetrahedron 55 (1999)14421
14
Heterocycl Commun 11 (2005) 129
15
Long-Bridge Merocyanines
J Chem Soc, Faraday Trans 93 (1997) 3653
Similar methodology as utilized for the synthesis
of simple merocyanines is useful for the
preparation of their cyclic higher vinilogues.
16
J Appl Spectroscopy 71(2004) 641
17
Structure and Isomerization

• Merocarbocyanines can exist as four transoid
  isomers with regard to two double bonds of the
  bridge fragment.

18
Solvatochromism
Acetone, 96  ethanol, acetic acid, water, DMF,
acetonitrile, 2-propanol, methanol, THF and DMSO
Solvatochromic merocyanines exhibit bathochromic
or hypsochromic shifts in solvents of various
polarities. Other characteristics such as dipole
moments, fluorescence, and NLO properties change
as well.
19
Ion Sensors
Titration with Ni2
20
Anal Chim Acta 504 (2004) 227
Calcium-sensitive chromogenic crown ethers. The
water-soluble dye (R CH3) can be used for
calcium ion sensing in solution while
lipophilized derivative (R C12H25) has been
successfully applied to ion-exchange type optode
PVC membranes.
21
Molecular Aggregation

• Molecular aggregates are self-assemblies of
  molecules by non-covalent interactions.
• They have significant technological applications
  such as molecular optoelectronic devices,
  fluorescence probes for mitochondrial membrane,
  and as models of antenna systems that function to
  transfer energy and electrons in biological
  systems

22
Langmuir 20 (2004) 5718-5723
Aggregation processes of merocyanine dyes on
lyposomes (artificial cell membranes)
23
Spiropyrans
24
3D data storage media
Schematic representation of a cross-section
through a 3D optical storage disc (yellow) along
a data track (orange marks). Four data layers are
seen, with the laser currently addressing the
third from the top. The laser passes through the
first two layers and only interacts with the
third, since here the light is at a high
intensity.
No commercial product based on 3D optical data
storage has yet arrived on the mass market,
although several companies are actively
developing the technology and claim that it may
become available "soon".
25
Photodynamic therapy
Merocyanine 540
J Photochem Photobiol B 32 (1996) 27-32
26
Non-linear properties
d 115 GM
d 25 GM
d 35 GM
d 125 GM
at 1064 nm
Optics Commun 281 (2008) 6072-6079
27
n 1 dmax 2300 GM (at 826 nm) n 2 dmax
5000 GM (at 900 nm) n 3 dmax 10000 GM (at
980 nm)
J. Mater. Chem. 19 (2009) 75037513
28
Conclusions

• Merocyanine dyes with nitrogen donor and carbonyl
  acceptor fragments have found a wide application
  in various areas of science and technology,
  including optical and fluorescent sensors, silver
  halide photography, optical data storage, and
  photodynamic therapy.
• The synthetic methods on merocyanines preparation
  allow to obtain dyes with a wide variety of
  electron donor and acceptor parts, and hence with
  various properties.
• Recent progress in computer science and
  nanotechnology have stimulated new
  investigations, including the studies in
  non-linear optics, and new areas of medicine.

29
Thank you for your attention