Synthesis, Characterisation and Anti-Fungal Activities of Some New
Copper(II) Complexes of Octamethyl Tetraaza-Cyclotetradecadiene

Tapashi G. Roy,Edward R. T. Tiekink,Saroj K. S. Hazari,Benu K. Dey,Samar Chakraborti

doi:10.1155/mbd.1999.345

Synthesis, Characterisation and Anti-Fungal Activities of Some New Copper(II) Complexes of Octamethyl Tetraaza-Cyclotetradecadiene

Tapashi G. Roy, Edward R. T. Tiekink + Show 3 more

Open Access

https://doi.org/10.1155/mbd.1999.345

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Abstract

The ligand Me8[14]diene, L, in its free state as well as in the dihydroperchlorate form, L.2HClO4, coordinates copper(ll) in different salts to yield a series of [CuLXx] Xy(H2O)z complexes where X = NO3, ClO4, NCS, Cl and Br; x and y may have values of 0 or 2 and z = 0, 1 or 2. The complex, [CuL(ClO4)2].2H2O is found to undergo axial ligand substitution reactions with SCN-, NO3 and Cl- to give a variety of substitution derivatives: [CuL(ClO4)m Xn] where X = NCS, NO3 and Cl; m = 0 or 1, and n = 1 or 2. The complexes .have been characterised on the basis of analytical, spectroscopic, magnetic and conductance data. The anti-fungal activities of the ligand and its complexes have been investigated against a range of phytopathogenic fungi.

Highlights

The synthetic macrocycles and their complexes have attracted attention owing to their wide variety of applications. This contribution focuses on the synthesis and characterisation of a series of copper(ll) complexes of octamethyl tetraazacyclotetradecadiene with the view of investigating their anti-fungal activities
It has been established that stereospecific condensation of 1,2diaminopropane with acetone yields only the 3,10-C-meso isomer of the macrocycle 3,5,7,7,10,12,14,14-octamethyl-1,4,8,1 1-tetraazacyclotetradeca-4,1 1-diene, L, as determined by
Owing to the steric hindrance of eight methyl groups in L, it was expected that the preparation of five- or six-coordinate complexes containing this ligand would be difficult

Summary

Introduction

On reaction with copper(ll) salts, L.2HCIO4 and L yield both four- and six-coordinate complexes of the general formula [CULXx]Xy(H20)z, where X NO3, CIO4, NCS, CI and Br; x and y may have values of 0 or 2; z 0, or 2. The conductance value at 0.0 ohm cm mol (Table 2) for this complex in CHCI3 solution is an indication of the non-electrolytic nature of the complex, i.e. both CIO4 groups are in the coordination sphere. This assignment, i.e. an octahedral geometry, has been confirmed by an X-ray structure determination [7]. The conductance value (64 ohm cm mol) of a pink-violet DMF solution, corresponding to an 1"1 electrolyte, is accounted for by the equilibrium between [CuL]Br2.2H20 and [CuLBr2].2H20 This observation suggests that the non-coordinating Br ions of [CuL]Br2.2H20 are forced into the coordination sphere to some extent. It is noteworthy that the decrease in activity upon coordination of this particular ligand was found to be less compared to that of sulphur containing compounds [14] but comparable to that observed in case of its saturated macrocyclic analogues [6]

Experimental

Anti-fungal activities

Results and discussion