3.5 Electronic spectral data

The assignments of the significant electronic spectral absorption band of the nanometal complexes are given in Table 3. Two absorption peaks were observed in the spectra range of 210–227 and 279–337 nm due to п-п\* and n-п\* transitions, respectively, due to benzene and the azomethine (CH=N) function [26, 29]. Moreover, the spectra of complexes indicate no significant absorption in the visible region due to the absence of f–f transition, since f–f transitions are Laporteforbidden and very weak in nature.


#### Table 3.

Magnetic moment and electronic spectral data of La(III) nanocomplexes.

#### 3.6 Magnetic susceptibility

The following equation was used to calculate the magnetic susceptibility of the La nanocomplexes:

$$X\_{\mathfrak{g}} = \frac{C(bal)(\mathfrak{1})\left(R - R^0\right)}{\mathbf{1}0^{-9}\mathbf{m}}\tag{1}$$

3.8 Powder X-ray diffraction studies

DOI: http://dx.doi.org/10.5772/intechopen.83558

estimated from Debye-Scherrer equation (Eq. (2)):

nanocrystals can be prepared by our procedure [23].

good agreement with that of the elemental analysis.

X-ray powder diffractogram of complex (1) nanoparticle.

θ, the corresponding incidence angle.

3.9 EDX spectra

3.10 SEM analysis

Figure 2.

25

The diffraction of X-rays from the planes of a crystal (diffraction analysis) is considered as one of the important methods of the analytical work. By using X-ray diffraction which depends on the crystal properties of solids, we can identify the crystal structure of various solid compounds and identify the actual compounds from its structure, and we can also determine the arrangement of molecules in crystal [30]. X-ray diffractometry is an important technique as it is a nondestructive, non-contrast, fast, and sensitive one. Obtained XRD data of H2L1 ligand and its La(III) complex 1 of nanoparticle (Figure 2) show that XRD pattern of the ligand is different in comparison with the XRD pattern of the nanocomplex. The obtained data indicate that the complex is more crystalline in nature than that of the ligand which has an amorphous phase. The average particle size of the complex (1) can be

Synthesis and Characterization of Nanocomplexes by Green Chemistry and Their Applications…

where β the breadth of the observed diffraction line at its half intensity maximum; K, the shape factor, 0.89; λ, the wavelength of the X-ray source used in XRD;

The average particle size of the nanoparticles is 15 nm. The sharp diffraction

The amount of elements present in the percentage level of the metal complexes was identified by EDX data [31]. EDX spectra are used to calculate the percentage level of the elements present in the metal complexes like C, O, N, S, and La that are present in the La(IIl) nanocomplex 2, shown in Figure 3. The revealed data are in

SEM technique was used to study the morphology and size of nanoparticles (Figure 4). It seems that the particles are semispherical with some agglomerations

peaks of the samples indicate that the well-crystallized lanthanum complex

L ¼ Kλ=β cosθ (2)

where C, calibration constant of standard; l, length of sample in filled tube; R0 , reading of empty sample tube; R, reading with sample; χ<sup>g</sup> gram magnetic susceptibility.

The gram magnetic susceptibility of the complexes was found in the range �2.2098 � <sup>10</sup>�<sup>6</sup> –(-2.3013 � <sup>10</sup>�<sup>6</sup> ) cm<sup>3</sup> mol�<sup>1</sup> , respectively. Negative values of χ<sup>g</sup> show that these complexes are diamagnetic in nature or there is no significant magnetic moment (Table 3).

### 3.7 Thermal analysis

Thermogravimetric analyses (TGA) of the La nanocomplexes were used to determine the thermal stability of the complexes, decide whether the water molecules are lattice or coordinated, and finally suggest a scheme for thermal decomposition of these chelates. In the present investigation, heating rates were suitably controlled at 10<sup>o</sup> C min�<sup>1</sup> under nitrogen atmosphere, and the weight loss was measured from the ambient temperature up to � <sup>600</sup><sup>o</sup> C. The weight loss for each chelate was calculated within the corresponding temperature ranges.

Also, TGA curve of the La(III) complex of nanoscale [(La)(L<sup>1</sup> )(NO3)(H2O)] (1) showed three thermal stages. The first stage represents the loss of H2O molecule of coordination, HNO3 and ½O2 with a found weight loss of 11.72% (cacld. 11.54%) within the temperature range of 130�180o C; the subsequent second step (180�300o C) corresponds to the loss of C5H3BrN2O with an estimated mass loss of 22.60% (calcd. 22.27%). The final stage at 300�520o C corresponds to loss of rest of the organic part (C12H7BrN3O2S2) with an estimated weight loss 44.25% (calcd. 43.94%) leaving 4 C and La metal as a metallic residue. The overall weight loss amounts is 78.57% (cacld. 77.75%):


Synthesis and Characterization of Nanocomplexes by Green Chemistry and Their Applications… DOI: http://dx.doi.org/10.5772/intechopen.83558
