Tapashi G. Roy

Synthesis, Characterisation and Antifungal Activities of Some New Copper(II) Complexes of Isomeric 3,5,7,7,10,12,14,14-Octamethyl-1,4,8,11-Tetraazacyclotetradecanes

Three isomeric Me8[14]anes, LA, LB and LC, undergo complexation with copper(II) salts to form a series of [CuLXn(H2O)x]Xy.(H2O)z complexes where L = LA, LB and LC; X = Cl, Br, NO3; n, x, y and z may have values of 0, 1 or 2. The complexes have been characterised on the basis of analytical, spectroscopic, magnetic and conductance data. Further, the X-ray crystal structure of one complex, [CuLB(OH2)2](NO3)2, has been determined. The antifungal activity of all three isomeric ligands and their complexes has been investigated against a range of phytopathogenic fungi.

Axial ligand substitution in diastereoisomeric trans-[Co(Me8 14ane)Cl2]+ complexes and their anti-fungal activities

Three isomeric Me8 14anes, LA, LB and LC, on aeration with cobalt(II) acetate tetrahydrate and subsequent treatment with concentrated HCl and HClO4, give green trans-[CoLCl2]ClO4 diastereoisomers. Whereas the macrocyclic ligands LA and LB yield two N-chiral diastereoisomers, LC gives one isomer. The complexes undergo axial ligand substitution with small ligands such as , SCN−, OH− and H2O to produce corresponding trans products. Anti-fungal activities of the complexes against a range of phytopathogenic fungi have been investigated.

Synthesis, electrolytic behaviour and antimicrobial activities of cadmium complexes of isomers of 3,10-C- meso -3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane

Reactions of two diastereoisomers of 3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecanes, Me8[14]ane (LA and LB) with Cd(NO3)2 in methanol produced trans-[CdL(NO3)2] (L = LA or LB). However, the third diastereoisomer, Me8[14]ane (LC) did not react with Cd(NO3)2. Trans-[CdLB(NO3)2] undergoes axial ligand substitution reactions with KSCN, KNO2, KCl, KBr and KI, in the ratio of 1 : 2 to yield white solid products corresponding to molecular formula [CdLBX2] where X = NCS−, , Cl−, Br− or I−. Characterization has been carried out on the basis of elemental analysis, IR, UV-visible and 1H-, 13C- and 113Cd-NMR spectroscopy, as well as by magnetic moment and conductivity measurement. These complexes show different electrolytic behaviours in different solvents. In chloroform, they are noneletrolytic indicating that both anions coordinate to cadmium(II) with retention of original molecular formula [CdLBX2]; their 1 : 2 electrolytic nature in water reveals the formation of diaquo complexes [CdLB(H2O)2]X2. On the other hand, conductance values corresponding to 1 : 2 electrolyte in DMF indicate the formation of square pyramidal complexes [CdLB(DMF)]X2. The antimicrobial activities of these ligands and their complexes have been tested against some selected fungi and bacteria.

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

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.

Characterization of Diastereoisomeric [Ni(Me8[14]ane)]2+ Cations

The isomeric Me8[l4]anes, designated by LA, LB and LC, on reaction with nickel(II) acetate tetrahydrate and subsequent addition of LiClO4·3HO yield yellow or orange-yellow square planar [NiL](ClO4)2 diastereoisomers. It has been possible to isolate two N-chiral diastereoisomers for each ligand and these give distinct infrared and 1H NMR spectra. The structures of these isomers have been assigned mainly on the basis of their 1H NMR spectra. One structure, namely [NiLBα ](ClO4)2, has been confirmed by x-ray crystallography.

Axial addition in diastereoisomeric [Cu(Me8 14ane)](ClO4)2 complexes: antifungal and antibacterial activities

A series of diastereoisomeric square planar copper(II) perchlorate complexes, [Cu(Me8[14]ane)](ClO4)2, undergo axial addition reactions with H2O, NCS− and to yield the octahedral species trans-[CuL1X2](ClO4) n (L1 = isomeric Me8[14]ane; X = H2O, NCS, NO2 or NO3; n = 2 when X = H2O; n = 0 when X = NCS, NO2 or NO3). The products have been characterized on the basis of analytical, spectroscopic, magnetic and conductance data. Some derivatives are unstable in open air and may react with adventious H2O to form diaquo complexes. Antifungal and antibacterial activities of the uncomplexed ligands, the square planar copper(II) complexes and their axial addition products have been investigated against a range of phytopathogenic fungi and bacteria.

SYNTHESIS AND CHARACTERIZATION OF COPPER(II) AND NICKEL(II) COMPLEXES WITH 1,5,8,12-TETRAAZACYCLOHEPTADECANE AND 1,5,8,12-TETRAAZACYCLOOCTADECANE

Abstract Copper(II) and nickel(II) complexes with 1,5,8,12-tetraazacycloheptadecane and 1,5,8,12-tetraazacyclo-octadecane have been synthesised. These complexes contain 8- and 9-membered chelate rings. The visible spectra of the copper(II) complexes show that the 5,6,5 chelate ring sequence is the most favourable geometry for coordination. The nickel(II) complex of 1,5,8,12-tetraazacycloheptadecane is square planar, but can be converted into corresponding octahedral complexes. The geometrical features of this macrocyclic ligand show that the 4-coordinate nickel(II) species is favoured over the 6-coordinate one.

Two solvatomorphic forms of a copper complex formulated as Cu(L(1))(ClO4)2·1.2H2O and Cu(L(1))(ClO4)2, where L(1) is 3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane.

Two copper complex solvatomorphs, namely (3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane)bis(perchlorato-κO)copper(II) 1.2-hydrate, [Cu(ClO4)2(C18H40N4)]·1.2H2O, (I), and (3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane)bis(perchlorato-κO)copper(II), [Cu(ClO4)2(C18H40N4)], (II), are described and compared with each other and with a third, already reported, anhydrous diastereomer, denoted (III). Both compounds present very similar centrosymmetic coordination environments, with the Cu(II) cation lying on an inversion centre in a distorted 4+2 octahedral environment, defined by the macrocyclic N4 group in the equatorial sites and two perchlorate groups in trans-axial positions [one of the perchlorate ligands in (I) is partially disordered]. The most significant difference in molecular shape is seen in the orientation of the perchlorate anions, and the influence of this on the intramolecular hydrogen bonding is discussed. The (partially) hydrated state of (I) favours the formation of chains along [011], while the anhydrous character of (II) and (III) promotes loosely bound structures with low packing indices.

cis-(Nitrato-κ(2)O,O')(2,5,5,7,9,12,12,14-octa-methyl-1,4,8,11-tetra-aza-cyclo-tetra-decane-κ(4)N,N',N'',N''')cadmium nitrate hemihydrate.

The CdII atom in the title complex, [Cd(NO3)(C18H40N4)]NO3·0.5H2O, is coordinated within a cis-N4O2 donor set provided by the tetradentate macrocyclic ligand and two O atoms of a nitrate anion; the coordination geometry is distorted octahedral. The lattice water molecule is located on a twofold rotation axis. N—H⋯O hydrogen bonds and weak C—H⋯O interactions link the complex cations into a supramolecular layer in the bc plane. Layers are connected by O—H⋯O hydrogen bonds between the lattice water molecule and the non-coordinating nitrate anion, as well as by weak C—H⋯O contacts.

Benzyl 2-methyl-3-[(E)-(thio­phen-2-yl)methyl­idene]dithio­carbazate

In the title compound, C14H14N2S3, the thione S atom and methyl group are syn, as are the two thioether S atoms. The molecule is twisted, the dihedral angles between the central (C2N2S2) residue and the pendent 2-thienyl and phenyl rings being 21.57 (6) and 77.54 (3)°, respectively. In the crystal, molecules assemble into a three-dimensional architecture via C—H⋯π interactions, involving both the five- and six-membered rings as acceptors, as well as S⋯S interactions [3.3406 (5) Å] between centrosymmetrically related 2-thienyl rings.