PMID- 18266819
OWN - NLM
STAT- MEDLINE
DCOM- 20080911
LR  - 20131121
IS  - 0031-8655 (Print)
IS  - 0031-8655 (Linking)
VI  - 84
IP  - 3
DP  - 2008 May-Jun
TI  - Solvochromic effects in model eumelanin compounds.
PG  - 620-6
LID - 10.1111/j.1751-1097.2007.00290.x [doi]
AB  - We have created an indolic compound which is ideally suited to the study of the 
      relationship between structure and function in eumelanin formation. 
      N-methyl-5-hydroxy-6-methoxyindole (MHMI) is stable in solid and liquid states, 
      highly soluble in a variety of solvents and forms a dimer only through the 4-4' 
      positions. The limited binding possibilities are due to functional groups 
      strategically placed to inhibit chemical interactions through the 2 and 7 
      positions. It forms a crystal structure with a remarkable packing arrangement, 
      with four monomers grouped in parallel pairs spaced 3.5 A apart within each unit 
      cell. Optical spectra reveal a multi-peaked absorbance profile similar to 
      5,6-dihydroxyindole (DHI) and N-acetyl-tryptophanamide (NATA), and strong 
      fluorescence emission with radiative quantum yields of 29% and 33% in benzene and 
      acetonitrile, respectively. The quantum yield is similar to that of 
      5,6-dihydroxyindole-2-carboxylic acid (DHICA) and shows that solvent aromaticity 
      by itself does not affect the yield. Solution in chloroform results in an almost 
      complete quenching of the fluorescence but an increase in emission is observed 
      with photoactivation. Crystallographic results shown here suggest new structural 
      possibilities for eumelanin and the controlled binding possibilities make this an 
      excellent model for monitoring changes in function with increasing oligomer size 
      in eumelanin formation.
FAU - Nighswander-Rempel, Stephen P
AU  - Nighswander-Rempel SP
AD  - Centre for Organic Photonics and Electronics, School of Physical Sciences, 
      University of Queensland, Brisbane, Queensland, Australia. 
      snighrem@physics.uq.edu.au
FAU - Mahadevan, Indumathy B
AU  - Mahadevan IB
FAU - Bernhardt, Paul V
AU  - Bernhardt PV
FAU - Butcher, Jessica
AU  - Butcher J
FAU - Meredith, Paul
AU  - Meredith P
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20080207
PL  - United States
TA  - Photochem Photobiol
JT  - Photochemistry and photobiology
JID - 0376425
RN  - 0 (Indoles)
RN  - 0 (Melanins)
RN  - 0 (Solutions)
RN  - 0 (Solvents)
RN  - 12627-86-0 (eumelanin)
RN  - 7V31YC746X (Chloroform)
SB  - IM
MH  - Chloroform/chemistry
MH  - Crystallography, X-Ray
MH  - Indoles/chemical synthesis/*chemistry
MH  - Melanins/*chemistry
MH  - *Models, Biological
MH  - Models, Molecular
MH  - Molecular Structure
MH  - Solutions/chemistry
MH  - Solvents/chemistry
MH  - Spectrometry, Fluorescence
MH  - Structure-Activity Relationship
EDAT- 2008/02/13 09:00
MHDA- 2008/09/13 09:00
CRDT- 2008/02/13 09:00
PHST- 2008/02/13 09:00 [pubmed]
PHST- 2008/09/13 09:00 [medline]
PHST- 2008/02/13 09:00 [entrez]
AID - PHP290 [pii]
AID - 10.1111/j.1751-1097.2007.00290.x [doi]
PST - ppublish
SO  - Photochem Photobiol. 2008 May-Jun;84(3):620-6. doi: 
      10.1111/j.1751-1097.2007.00290.x. Epub 2008 Feb 7.