Nuclear magnetic resonance measurements determine which metallochlorophylls, besides magnesium-containing chlorophylls, possess coordination aggregation properties. Infrared spectroscopy reveals that only zinc pheophytin and zinc methyl pheophorbide showed significant coordination aggregation, whereas divalent nickel and copper did not

Boucher, L. J.

Katz, J. J.

English

NASA Technical Reports Server

	June 1969	 Brief 69-10163 
•	
Icy e
AEC-NASA TECH BRIEF 
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of theU.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
application. Tech Briefs are published by NASA and may be purchased, at 15 cents each, from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Aggregation of Metallochiorophylls: Examination by Spectroscopy 
.
Is coordination aggregation a unique property of 
magnesium-containing chlorophylls, or do other metal-
lochiorophylls behave similarly? The aggregation 
properties of metallochiorphylls had not been studied 
in detail before recent presentation (1) of new infor-
mation, derived from infrared and nuclear magnetic 
resonance (NMR) measurements, on the aggregation 
behavior of divalent nickel, copper, and zinc chloro-
phylls. 
Metal ions play a decisive, but still little understood, 
role in the photosynthetic unit. Chlorophyll, the most 
important compound of photosynthesis, is a magne-
sium (II) complex of dihydroporphyrin (chlorin) 
liquid. Examination of chlorophyll derivatives in 
which magnesium is replaced by other metal ions 
(metallochiorophylls) is valuable in providing infor-
mation about the contribution by the metal to the 
various properties and functions of chlorophyll. The 
state of aggregation of chlorophyll is a property re-
quiring special attention. 
The tendency to self-aggregation of divalent nickel, 
copper, and zinc methyl pheophorbides a and b was 
examined by infrared spectroscopy (1). Of these, only 
the zinc compounds show significant coordination ag-
gregation. Measurements by NMR on zinc pheophytin 
a and zinc methyl pheophorbide a and b show that 
both coordination aggregation and aggregation occur 
in nonpolar solvents. However, NMR and infrared 
measurements indicate that under comparable condi-
tions in nonpolar solvents the zinc chlorophylls are 
aggregated to a considerably lesser extent than are 
magnesium chlorophylls. 
Visible and infrared spectra of nickel, copper, and 
zinc methyl pheophorbides a and b are reported (1)
and tentative band assignments are made. Considera-
tions of absorption position and relative intensities 
suggest that the extent of metal-ligand interaction fol-
lows the order Ni>Cu>Zn>Mg. The materials used 
(1) were chromatographically pure, and their visible, 
ultraviolet, infrared, and NMR spectra are entirely 
compatible with their presumed molecular structures. 
Reference: 
L. J. Boucher and J. J. Katz, J. Amer. Chem. Soc. 
89, 4703 (1967). 
Notes: 
1. This information may be useful to horticulturists 
and canners of green vegetables. 
2. Inquiries may be directed to: 
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B69-10163 
Source: L. J. Boucher and J. J. Katz 
Chemistry Division

Argonne National Laboratory 
(ARG-10273) 
Patent status: 
Inquiries concerning rights for commercial use of 
this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439
Category 04 
This document was prepared under the sponsorship of the Atomic 
Energy Commission and/or the National Aeronautics and Space 
Administration. Neither the United States Government nor any per-
son acting on behalf of the United States Government assumes any
liability resulting from the use of the information contained in this 
document, or warrants that the use of any information, apparatus, 
method, or process disclosed in this document may not infringe pri-
vately owned rights.
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Aggregation of metallochlorophylls - Examination by spectroscopy

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