Abstract:
The crystal structure of Cu(PM)2(N03hoH20 (where PM is pyridoxamine,
CSHI2N202) has been determined from three dimensional x-ray diffraction data.
The crystals are triclinic, space group pI, a = 14.248 (2), b = 8.568 (1),
c = 9.319 (1) 1, a = 94.08 (1), e = 89.73 (1), y~~ 99.18 (1)°, z = 2,
jl(MoK) = 10.90 em-I, Po = 1.61 g/cm3 and Pc = 1.61 g/em3• The structure
a
was solved by Patterson techniques from data collected on a Picker 4-circle
diffractometer to 26max = 45°. All atoms, including hydrogens, have been
located. Anisotropic thermal parameters have been refined for all nonhydrogen
atoms. For the 2390 independent reflections with F ? 3cr(F) ,
R = 0.0408.
The results presented here provide the first detailed structural
information of a metal complex with PM itself. The copper atoms are
located on centres of symmetry and each is chela ted by two PM zwitterions
through the amino groups and phenolate oxygen atoms. The zwitterionic form
found in this structure involves the loss of a proton from the phenolate
group and protonation of the pyridine ring nitrogen atoms. The two
independent Cu(PM)2 moieties are symmetrically bridged by a single oxygen
atom from one of the nitrate groups. The second nitrate group is not
coordinated to the copper atoms but is central to an extensive hydrogen
bonding network involving the water molecule and uncoordinated functional
groups of PM.
