Y. Funahashi et al., STRUCTURES AND SPECTRAL PROPERTIES OF IRON(II), COBALT(II), AND COPPER(II) COMPLEXES INVOLVING 2-(DIMETHYLAMINO)-4(3H)-PTERIDINONE, Inorganic chemistry, 36(18), 1997, pp. 3869-3875
With a view to understanding the pterin cofactor-metal ion interaction
s, some divalent transition metal complexes containing 2-(dimethylamin
o)-4(3H)-pteridinone (NDMP), M(NDMP)(2)(CH3OH)(2) (M = Fe(II) (1), Co(
II) (2), Cu(II) (3)) and Fe(NDMP)(2)Cl-2 (4), have been prepared and i
nvestigated by magnetic, spectroscopic, and X-ray diffraction methods.
Complexes 1, 2, and 4 were found to be in a typical high-spin state,
and complex 3 was found to be in a d(x2-y2) ground state. Complexes 1-
3 were structurally determined. [Fe(NDMP)2(CH3OH)(2)]. 2CH(3)OH (1) cr
ystallizes in the triclinic system, space group <P(1)over bar>, with a
= 8.54(1) Angstrom, b = 9.353(10) Angstrom, c = 8.45(2) Angstrom, alp
ha = 96.5(1)degrees, beta = 98.3(2)degrees, gamma = 79.13(9)degrees, V
= 653 Angstrom(3), and Z = 2. [Co(NDMP)(2)(CH3OH)(2)]. 2CH(3)OH (2) i
s isomorphous with 1 with a = 8.4753(6) Angstrom, b = 9.430(1) Angstro
m, c = 8.3695(5) Angstrom, alpha = 95.885(7)degrees, beta = 98.412(6)d
egrees, gamma = 79.421(8)degrees, V = 648.48 Angstrom(3), and Z = 2. [
Cu(NDMP)(2)(CH3OH)(2)] (3) crystallizes in the monoclinic system, spac
e group P2(1)/a, with a = 8.428(1) Angstrom, b = 14.3857(8) Angstrom,
c = 8.9570(8) Angstrom, beta = 95.225(8)degrees, V = 1081.5 Angstrom(3
), and Z = 4. The final R and R-W values are 0.042 and 0.033 fbr 1, 0.
056 and 0.040 for 2, and 0.040 and 0.018 for 3, respectively. The geom
etries around the metal ions are essentially the same, and each metal
ion is octahedrally coordinated with 4-carbonyl oxygens and fi-nitroge
ns of NDMP molecules in the equatorial positions and two methanol mole
cules in the axial positions. The Fe(II) complexes 1 and 4 exhibited a
n absorption band centered at 568 nm (epsilon = 1900 M-1 cm(-1)) in DM
F and a peak at 674 nm in the reflectance spectrum, respectively, both
of which are assigned to a charge transfer. This and other spectrosco
pic and structural properties have been comparatively discussed.