J, Indian Chern. Soc., NOTE Vol. 81, February 2004, pp. 147-149 Synthesis of some Schiff base complexes of nickel(II) and copper( II) derived from p-dimethylaminobenzaldehyde Vivek Tiwari*, Rashmi Singhai and A. P. Mishra Department of Chemistry, Dr. H. S. Gour University, Sagar-470 003, India E-mail : rashmitiwari @epatra.com; apm 19@rediffmail.com Manuscript received 22 May 2002, revised 20 May 2003, accepted 17 July 2003 Complexes of Ni 11 and Cu 11 with Schiff bases 4-dimelhylaminobenzylidene-4-chloroaniline (DABCA)/4- dimethylaminobenzylidene-4-bromoaniline (DABBA)/4-dimethylaminobenzylidene-3-nitroaniline (DABNA) of general formula ML(H 2 0) 2 CI 2 .2H 2 0 and MLCI 2 (H 2 0) 2 .2H 2 0 have been synthesized. Coordination of azomethine nitrogen in the Schiff base to the metal has been proposed. Ligand field parameters of some of the complexes have been calculated. Schiff base complexes with transition metals have played a prominent role in the development of coordination chemis- try1. Several Schiff base metal complexes have been stud- ied because of their industrial and biological applications 2 ·3. Some organometallic complexes of transition metals derived from substituted anilines have been investigated 4 --6. The present investigation aims at the study ofNi 11 and Cu 11 com- plexes with some bioactive ligands (Schiff base) derived from 4-dimethylaminobenzaldehyde and substituted ani lines. Results and discussion Complexes of Nil/ and Cu 11 with 4-dimethylamino- benzylidene-4-chloroaniline ( DABCA) : The analytical re- sults show that metal-to-ligand ratio is 1 : I in the com- plexes (Table 1). The molar conductance values (I o- 3 Min methanol) of the Nin and Cu 11 complexes are in accordance with uni-bivalent electrolytic nature and non-electrolytic nature of the complexes, respectively 7 . The diamagnetic na- ture of the Nill complex suggests the square-planar geom- etry. The Cu 11 complex gives J.leff value 1.91 B.M. TheIR ligand band of the -N(CH 3 ) 2 group (2830 cm- 1 ) on chelation appears at higher frequencies, i.e. 2860 ± I 0 cm- 1 in the Nin and Cu 11 complexes. The C-N (due to -N(CH3) 2 group) band shifts to lower frequency region by 40-50 cm- 1 in the complexes 8 - 10 . The C=N (azomethine) ligand band ( 1610 cm- 1 ) shifts down by about 40-50 cm- 1 in the complexes, indicating the participation of azomethine nitrogen in coordination4- 10 . In the spectra of both the com- plexes, band at 3400-3500 cm-:- 1 and 770 ± 10 cm- 1 arc assignable to stretching and rocking mode of coordinated water molecules, respectively. The new bands in the com- plexes at 500 ± 10 and 430 ± 10 cm- 1 have been assigned to vM-0 and vM-N• respectively. Further a band at 290 cm- 1 J/CS-8 Table 1. Analytical and physico-chemical data of the complexes* Compd. Colour/M.p.°C Metal% Mol.cond. fleff Found/(Calcd.) .Q- 1 cm2 mol-l B.M. (DABCA) Yellow 110 [Ni (DABCA) Brown 11.84 212.0 Diamag. (H 2 0) 2 1CI 2 . 128 (12.70) 2H 2 0 [Cu(DABCA) Black 13.40 29.60 1.91 CI 2(H20hl- 136 (13.64) 2Hz0 Yellow (DABBA) 85 [Ni(DABBA) Buff 5.88 27.1 3.12 CI 2 CH 2 0) 2 ). 100 (5.40) 2H 2 0 [Cu(DABBA) Buff 5.68 34.80 1.84 CI 2 ].H 2 0 liS (5.96) (DABNA) Orange 120 [Ni(DABNA) Brown 11.91 218.3 Diamag. (H 2 0) 2 J 165 (12.40) CI 2 .2H 2 0 [Cu(DABNA) Brown 12.80 32.40 1.94 CI 2 (H 2 0) 2 ]. 135 ( 13.34) 2H 2 0 *All compounds gave satisfactory C, Hand N analyses. in the Cu 11 complex is probably due to VM-Cl 9 • 10 . The electronic spectrum of the Ni 11 complex shows two bands at 12345 and 18180 cm- 1 , assigned to 1 A 1 g 1 Eg (v 1 ) and 1 A 1 g 1 B 2 g (v 2 ) transitions. The third band ap- pears obscured by a strong charge transfer band. This sug- gest a square-planar geometry. The electronic spectrum of the Cu 11 complex gives a broad band which is splitted slightly giving peaks at 12658 and 16393 cm- 1 clEg 2 T 2 g transi- tion). The ligand field parameters 10 Dq, A.' and LFSE were 147