Subject: Paramagnetically shifted 1H NMR spectra

From: Arvydas Tamulis <[email-masked]>
Date: Sun, 11 Feb 2001 19:47:23 +0200 (EET)

Dear Netters,

We did not succeeded to calculate paramagnetically shifted 1H NMR spectrum
of biliverdin molecule CuOEB using Gaussian 98 (see experimental data in
J. Am. Chem.Soc., vol. 115, p. 12206 (1993)).

We have optimized geometry of TeMeSilane molecule and obtained from NMR
calculation the Isotropic Shielding values for H atoms (in ppm):

   H    Isotropic =    31.9027   Anisotropy =     9.6413
   XX=    29.4642   YX=     0.2951   ZX=    -0.7329
   XY=     0.4642   YY=    32.9871   ZY=    -5.1492
   XZ=    -0.8947   YZ=    -5.1015   ZZ=    33.2567
   Eigenvalues:    27.9348    29.4430    38.3302

We have used Density Functional Theory B3PW91/6-311G**

We have taken geometry of CuOEB from X-Ray experiment.
Our B3PW91\6-311G** calculated CuOEB NMR  Hm shielding values (ppm):
 23  H    Isotropic =    28.4781   Anisotropy =    10.0683
   XX=    24.0637   YX=    -1.2135   ZX=     -.8179
   XY=     -.0906   YY=    35.1141   ZY=    -2.2717
   XZ=     9.0739   YZ=     1.6948   ZZ=    26.2566
   Eigenvalues:    20.8808    29.3633    35.1904

 60  H    Isotropic =    27.5216   Anisotropy =    12.3793
   XX=    22.4061   YX=     2.7621   ZX=    -1.0495
   XY=     -.3733   YY=    35.4454   ZY=     2.7019
   XZ=    10.0293   YZ=    -6.4196   ZZ=    24.7134
   Eigenvalues:    18.6646    28.1258    35.7745

 and shielding Hm' value:
24  H    Isotropic =    25.8868   Anisotropy =    16.3237
   XX=    36.5750   YX=     -.6396   ZX=     4.7813
   XY=     -.0379   YY=    23.9614   ZY=      .1694
   XZ=     -.9100   YZ=     2.3766   ZZ=    17.1241
   Eigenvalues:    16.7005    24.1907    36.7693

It means that our calculated chemical shifts for Hm and Hm' are equal to
few ppm while CuOEB experimental NMR chemical shift values for Hm and Hm' in
J. Am. Chem.Soc., vol 115, p. 12206 are equal approximately to 135 ppm and
-100 ppm.

Why so badly we have calculated paramagnetically shifted 1H NMR spectrum
for CuOEB molecule?
Maybe GAUSSIAN is not able to calculate paramagnetically shifted 1H NMR
spectra?
Which program is suitable for calculations of paramagnetically shifted 1H
NMR spectra?

Thanking your in advance.
With best regards, Arvydas Tamulis & Jelena Tamuliene
*******************************************************
           Arvydas Tamulis

Doctor of Natural Sciences, senior research fellow

Institute of Theoretical Physics and Astronomy,
Theoretical Molecular Electronics Research Group,
A. Gostauto 12, Vilnius 2600, Lithuania
e-mail: [email-masked]; WEBsite: http://www.itpa.lt/~tamulis/
fax: +(370-2)-225361  or  +(370-2)-224694
Phone: +(370-2)-620861
Home address: Didlaukio 27-40, Vilnius 2057, Lithuania
Phone: +(370-2)-778743