446
B.L.HIRAN et al.
Table 1. Analysis of FMBA - metal complexes
Elemental analysis, %
H %
Calcd. Found Calcd. Found Calcd. Found Calcd. Found
Metal complex
Yield
%
C %
N %
Metal %
Mol.Wt
C26H20 N2O8 Cu2+
.2H2O
587.54 80
582.71 85
582.93 82
53.10 53.0 4.08 4.0 4.16 4.7 10.81 10.7
C26H20 N2O8 Ni2+
.2H2O
2+
C26H20N2O8 CO
53.54 53.4 3.43 9.3 4.80 4.7 10.70 10.0
10.0
.2H2O
53.52 53.4 3.43 3.3 4.80 4.7 10.05
C26H20 N2O8 Zn2+
80
588.39
53.02 52.9 3.40 3.3 4.75 4.6 11.08 11.0
.2H2O
C26H20 N2O8 Mn2+
.2H2O
578.93 79
53.89 53.7 4.14 4.1 4.83 4.7 9.48
9.4
The metal complexes showed the slightly less broad band between 3600-3200 cm-1
compared to that of ligand FMBA. This might be due to presence of coordinated water
molecule. The bands due to amide υC = 0 mode around 1650 cm-1 for the free ligands are shifted
to higher frequency in all the complexes indicating involvement of the carbonyl oxygen of the
amide group in coordination and non involvement of the amide nitrogen10,11. The absorption
band around 1700 cm-1 and 1300 cm-1 in the free ligands attributed to υC=o and υC-OH of the
carbonyl group12. They are replaced by two bands in the region of 1540-1590 cm-1 and 1340-
1380 cm-1 corresponding to υC00 (assymm.) and υC.0 (symm.) in all the complexes.
The infrared spectra of all the complexes are identical and suggest the formation of the entire
metalocyclic compound by the absence of band characteristic of free -OH group of parent FMBA.
The other bands are almost at their respectable positions as appeared in the spectrum of parent-
FMBA ligand. However, the band due to (M-O) band could not be detected as it may be appeared
below the range of instrument used. The important IR spectral data are shown in Table 2.
Magnetic moments of metal complexes are given in Table 2. The diffuse electronic
spectrum of Cu2+ chelate show two broad bands around 13000 and 23000 cm-1. The first
2
2
band may be due to a B1g - A1g transition, while the second band may be due to charge
transfer. The first band shows structures suggesting a distorted octahedral structure for the
Cu2+ metal chelates13,14 .The higher value of the magnetic moment of the Cu2+ chelate
supports the same. The Co2+ metal chelate gives rise to two absorption bands at 23800 and
19040 CMT, which can be assigned 4T1g - 4T1g - 4T1g (P) transitions respectively15,16
The spectrum of Mn2+ polymeric complex comprised two bands at 19010 cm-1 and
23300 cm-1. The latter does not have a very long tail. These bands may be assigned to 6A1g
.
-
6
4
42g(G) and A1g - A2g(G) transitions, respectively. The high intensity of the bands suggests
that they may have some charge transfer character. The magnetic moment is found to be
lower than normal range. In the absence of low temperature measurement of magnetic
moment it is difficult to attach any significance to this. As the spectrum of the metal chelate
of Ni2+ has two distinct bands at 11960 - 11450 and 17700-17400 cm-1 which are assigned as
3
3
3A2g (F) - T1g (F) and A2g (F) - T1g (F) transitions, respectively suggested the octahedral
environment for Ni2+. The observed µeff values are in the range 3.01 - 3.2 moiety14,15
.
The examination of antifungal activity of FMBA ligand and its all complexes (Table 3)
reveals that the ligand is moderately toxic against fungi, while all the chelates are more toxic
than ligand. Among all the chelates, the Cu2+ complex is more toxic against fungi.
Patel
