Results and dissection
3.1 Transition metal complexes of the macrocyclic, H6L Ligand
3.1.1 The macrocyclic, H6L Ligand
The physical and analytical data of the macrocyclic, H6L ligand and its transition metal complexes were shown in Table 1. From the investigation, the expected structure of H6L with its possible toutomeric forms can be represented as shown in Figure 1.
H6L ligand is highly symmetric under the point group C2v symmetry and can show all the normal modes of vibrations by solving the irreducible representation under C2v. For simplicity, the macrocyclic, H6L, ligand can be divided into two (I and II) moieties which are repeated twice in the structure of the molecule. Figure 2 represents the structure of the two (I and II) moieties …show more content…
3) Broad bands in the range (3571-3361 cm-1) can be assigned to the stretching frequencies of (OH) of either water or methanol molecules associated with the complexes which are also confirmed from elemental analysis. 4) Amide II, (NH), occurs at 1528 cm-1 in the free ligand are shifted to lower frequencies in the range 1530-1523 cm-1, except in the case of Cd(II), Fe(III) and Cr(III) which appear at higher frequencies at 1549-1537 cm-1. Amide III (C-N) occurs at 1324 cm-1 in the free ligand while in the metal complexes appeared at the same range 1313-1336 cm-1. This means there is no significant effect on this band during the coordination. 5) The appearance of a broad band of (NH) at 3213-3151 cm-1 compared to the corresponding stretching frequency of the free ligand 3177 cm-1, which means that there is no significant effect on these bands during the coordination. 6) The weak band in region 478-420 cm-1 could be assigned to (M-N). 7) The NO3- ion is coordinated to the metal ion as unidentate for the Ni (II), Cu (II), Fe (III) and Cr (III) complexes with C2v symmetry. The unidentate nitrate group possess three non-degenerated modes of vibrations (s, s' and as) which appeared at 1454, 1309, 1104 cm-1 for Fe (III). The free NO3- ions have also three modes of vibrations (s, s' and as) which appeared at (1760 and 1700) and 1707 cm-1 for the Ni (II) and Cd (II) complexes, respectively. The Cr (III) complex has coordinated and uncoordinated NO3- which appeared at 1761, 1290 and 1108
3.1 Transition metal complexes of the macrocyclic, H6L Ligand
3.1.1 The macrocyclic, H6L Ligand
The physical and analytical data of the macrocyclic, H6L ligand and its transition metal complexes were shown in Table 1. From the investigation, the expected structure of H6L with its possible toutomeric forms can be represented as shown in Figure 1.
H6L ligand is highly symmetric under the point group C2v symmetry and can show all the normal modes of vibrations by solving the irreducible representation under C2v. For simplicity, the macrocyclic, H6L, ligand can be divided into two (I and II) moieties which are repeated twice in the structure of the molecule. Figure 2 represents the structure of the two (I and II) moieties …show more content…
3) Broad bands in the range (3571-3361 cm-1) can be assigned to the stretching frequencies of (OH) of either water or methanol molecules associated with the complexes which are also confirmed from elemental analysis. 4) Amide II, (NH), occurs at 1528 cm-1 in the free ligand are shifted to lower frequencies in the range 1530-1523 cm-1, except in the case of Cd(II), Fe(III) and Cr(III) which appear at higher frequencies at 1549-1537 cm-1. Amide III (C-N) occurs at 1324 cm-1 in the free ligand while in the metal complexes appeared at the same range 1313-1336 cm-1. This means there is no significant effect on this band during the coordination. 5) The appearance of a broad band of (NH) at 3213-3151 cm-1 compared to the corresponding stretching frequency of the free ligand 3177 cm-1, which means that there is no significant effect on these bands during the coordination. 6) The weak band in region 478-420 cm-1 could be assigned to (M-N). 7) The NO3- ion is coordinated to the metal ion as unidentate for the Ni (II), Cu (II), Fe (III) and Cr (III) complexes with C2v symmetry. The unidentate nitrate group possess three non-degenerated modes of vibrations (s, s' and as) which appeared at 1454, 1309, 1104 cm-1 for Fe (III). The free NO3- ions have also three modes of vibrations (s, s' and as) which appeared at (1760 and 1700) and 1707 cm-1 for the Ni (II) and Cd (II) complexes, respectively. The Cr (III) complex has coordinated and uncoordinated NO3- which appeared at 1761, 1290 and 1108