Synthesis of Dodecaaza-tetrachlorotricyclodotriacontane (DACD) Macro Cyclic Complexes of Transitional Metal Ions (cu++) Present in Pulp and Paper Mill Effluents

Some of the metals such as Ni, Co, Cu, As, Hg, Pb, Zn, Cr etc. are highly toxic to         human beings and when absorb in small quantity. In this paper an attempt is made to discuss studies in relation with transitional metal like Cu, its source, effect on health and its physio-chemical property.

In the present investigation di-polymetallic complexes of Cu (II) have been derived from polyamines. Template condensation of chloro carbon such as hexachloroethane with tri-amine such as diethylenetriamine in presence of Cu (II) which was formed by the Pulp and Paper mill effluent yield the corresponding metal complex of the following macro cyclic legend – 3,6,9,12,15,18,19,22,25,26,29,32-dodecaaza-1,2,10,11-tetrachlorotricyclo[9.7.7.7] dotriacontane (DACD) (Figure 1).

 

Figure 1: Macro cyclic legend – ,6,9,12,15,18,19,22,25,26,29,32-dodecaaza-1,2,10,11-tetrachlorotricyclo[9.7.7.7] dotriacontane (DACD) Click here to View figure

 

Figure 2: Cu (II) complex of ,6,9,12,15,18,19,22,25,26,29,32-dodecaaza-1,2,10,11-tetrachlorotricyclo[9.7.7.7] dotriacontane (DACD)  Click here to View figure

 

Results and Discussion

In the condensation of diethylenetriamine with hexachloroethane in presence of copper hydroxide under similar reactant molar ratio dodecaaza macrocyclic ligand 3,6,9,12,15,18,19,22,25,26,32-dodecaaza-1,2,10,11-tetrachlorotricyclo[9.7.7.7] dotriacontane (DACD) is generated. The metal complex [Cu₄(DACD)(H₂O₄]Cl₈ is tetranuclear. Cyclization proceeds by condensation of hexachloroethane with copper coordinated diethylenetriamine. Each copper (II) is a square planer structure is surrounded by three aza groups of the macrocyclic and one water molecule.

Conductivity data of the complex was recorded using their 0.01 M aqueous solution, with the help of a DDR Conductivity meter type 304. Mass spectra were recorded at the RSIC, CDRI Lucknow. A Jeol D-300 (El/Cl) spectrometer was used for obtaining the mass spectra of the ligand hydrochlorides of low molecular weight. Infrared spectra in the range 4000-250cm^-1 were recorded by Perkin Elmer infrared spectrometer in KBr pellets at Regional Sophisticated Instrumentation Centre, C.D.R.I. Lucknow. The pmr spectra were taken in D₂O solution and recorded on Bruker DRX300 (300 MHz. PT NMR) using tetra methyl silane as an internal standard (Table 1).

Table 1: Analytical and physical data of the Macrocyclic Compounds derived from Diethylenetriamine Click here to View table

In the infrared spectrum of the copper-DACD complex the medium but sharp N-H stretching modes of only secondary amine groups appear at 3125cm^-1.The compound exhibits a δ (N-H) vibrations at 1582 cm^-1.Very sharp bands at 1070 (strong) and 440 cm^-1(medium) frequencies may be assigned to ν(C-N) and ν(Cu-N), respectively. Vibrations for C-H asymmetric (medium, sharp), symmetric (weak, sharp) and scissoring (medium) are seen at 2920, 2870 and 1442 cm^-1respectively. The presence of coordinated water is indicated by appearance of a strong and sharp band at 3220 cm^-1 followed by other peaks at 830,620 and 518 cm^-1 attributed to O-H stretching, rocking, wagging and ν (Cu-O) ,respectively.

The metal-free macrocyclic molecules DACD.12HCl exhibits a very strong but very broad band in the region 3200-2800 cm^-1assigned to ν (C-N). A C-H scissoring peak appears at 1489 cm^-1. The ν (N-H) vibration for secondary amine is not seen, probably due to its coupling with the strong and broad ν (C-H) vibrations. A peak at 1605 cm^-1 may be attributed to N-H bending vibration. The number of weak bands associated with the amine hydrochloride in the region 2800-2000 cm^-1 is low. A weak but broad band for ν (C-N) appears at 1110 cm^-1.

Compound	IR Bands (cm-1) Table1.2:  for Important IR Bands of the Macrocyclic Compounds Derived from Diethylenetriamine
[ Cu4(DACD)(H2O)Cl8	3220(s,sp), 3125(m,sp), 2920(m,sp), 2870(w,sp), 1582(m,sp), 1442(m), 1380(w,vsp), 1360(vw,sp), 1290(v,csp), 1240(m,sp), 1140(m,vsp), 1070(s,vsp), 1020(s,vsp), 986(m,vsp), 940(m,sp), 892(w,vsp), 860(vw,vsp), 830(vw), 620(m,vsp), 518(m,vsp), 440(m,vsp), 383(w,vsp), 342(w,vsp), 315(vw,sp), 250(vw).

*Abbreviations Used: b = broad, d = doublet, m = medium, s = strong, sh = shoulder, sp = sharp, vb = very broad, vs = very strong, vsp = very sharp, vw = very weak, w = weak

Figure 3: IR Spectra of [Cu4(DACD)(H2O)4]Cl8  or   Cu4C20H52N12O4Cl12 Click here to View figure

The pmr spectrum of DACD hydrochloride can be resolved into three distinct regions due to NH₂⁺ and two monequivalent CH₂ protons. It shows a broad singlet at 4.99 ppm assigned to NH₂⁺ resonances. The remaining two signals for nonequivalent CH₂ protons are broad triplets centred at 3.47 and 3.55 ppm (J-6.00 Hz).The first triplet resonance is attributed to the CH₂ proton bonded to

groups whereas the second resonance is assigned to the remaining CH₂ protons. The relative areas of the two triplets being identical correspond to the expected protons.

Determination of molecular weight by mass spectra of the compound DACD.12HCl by FABMS has been very useful in completing their characterization .The highest mass peaks found in the spectrum occur at m/z values close to their molecular ions (Table 1.1) and are very weak and are comparable to those observed in earlier reported aza macrocyclic complexes.

[Cu₂(DACD) (H₂O)₄]Cl₈ compounds are highly soluble in water and generally in polar solvents like ethanol, methanol, DMF etc.The molecular conductivity of the complexes and number of ionizable chloride ion in all macrocyclic molecules recorded in Table 1.1 are in support of their ionic structures. The complex Copper-DACD is 8:1 electrolytes. The molar conductance value 968 ohm^-1 cm² mol^-1 determined for Copper-DACD complex. The copper complex is blue or deep blue. The metal-free ligand hydrochloride DACD-12HCl is yellowish-white in colour. This compound is thermally stable and decomposes above 200⁰C

Conclusion

According to the result of this study, transition metal ions present in pulp and paper mill effluents can be isolated and treated with equimolar amount of diethylenetriamine and hexachloroethane, macrocyclic complexes are formed. The above procedures outlined for the preparation of the resultant macrocyclic complexes are facile and appear to proceed smoothly.  This is used as electro catalyst in fuel cell, enhances the electrical conductivity. It should prove useful for investigation of metal containing-biological molecules such as metalloenzymes and their catalytic activity for industries.

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