A new tetradentate N2O2-type Schiff base ligand. Synthesis, extractive properties towards transition metal ions and X-ray crystal structure of its nickel complex

Abstract

A new tetradentate N 2 O 2 -type Schiff base, bis(2-hydroxypropiophenone)-1,2-propanediimine (L), was synthesized by the reaction of 1,2-propanediamine with 2-hydroxypropiophenone in EtOH. The Schiff base is able to extract Co II , Ni II , Cu II and Zn II ions in aqueous NaNO 3 media into a CH 2 Cl 2 organic phase via a cation exchange mechanism. The observed extraction order was as follows: Cu II > Ni II > Co II > Zn II . Reaction of nickel acetate with the Schiff base in EtOH afforded the neutral complex Ni AE L. Single crystals of this complex were obtained from mixed CHCl 3 -EtOH (3:1) solvent and its structure was determined by X-ray diffraction. Crystal data for Ni AE L AE CHCl 3 : triclinic, space group P" , with a = 9.005(2) Å , b = 9.625(2) Å , c = 14.212(4) Å , V = 1136.8(5) Å 3 , a = 106.06(2)°, b = 106.06(2), c = 105.10(2)°, and Z = 2. A near square planar structure is observed for the studied complex.

Synthesis, crystal structures, and antimicrobial activity of two thiocyanato-bridged dinuclear copper(II) complexes derived from 2,4-dibromo-6-[(2-diethylaminoethylimino)methyl]phenol and 4-nitro-2-[(2-ethylaminoethylimino)methyl]phenol

“…The Cu-N and Cu-O bond lengths involving the basal planes range from 1.906(4) to 2.078(4) Å for [Cu 2 (L1) 2 (l-NCS) 2 ] and 1.933(4)-2.045(4) Å for [Cu 2 (L2) 2 (l-NCS) 2 ], which agree well with those generally observed in five-coordinate copper(II) complexes [22][23][24] In the crystal structure of [Cu 2 (L2) 2 (l-NCS) 2 ], adjacent dimers are linked through intermolecular N-HXXXO O1-Cu1-S1 i 93.9(2) N1-Cu1-S1 i 88.8 (2) N2-Cu1-S1 i 97.6(2) N3-Cu1-S1 i 93.3 (2) [Cu 2 (L2) 2 (l-NCS) 2 ]…”

“…The asymmetric units in each of the complexes are related by a center of inversion, to form Cu(II) dimer molecules in which the metallic cations are connected through two endto-end thiocyanate bridges. The intra-dimer CuÁÁÁCu distance across the thiocyanate bridges is 5.601(2) Å for [Cu 2 (L1) 2 (l-NCS) 2 ], which is slightly longer than the corresponding value of 5.511(2) Å for [Cu 2 (L2) 2 (l-NCS) 2 ]. This might be caused by the larger hindrance effect of the diethyl groups in [Cu 2 (L1) 2 (l-NCS) 2 ] than that for the ethyl groups in [Cu 2 (L2) 2 (l-NCS) 2 ].…”

“…This might be caused by the larger hindrance effect of the diethyl groups in [Cu 2 (L1) 2 (l-NCS) 2 ] than that for the ethyl groups in [Cu 2 (L2) 2 (l-NCS) 2 ]. Each Cu atom is located in a distorted square pyramidal coordination sphere as revealed by the trigonal index, s = 0.165 for [Cu 2 (L1) 2 (l-NCS) 2 ] and 0.167 for [Cu 2 (L2) 2 (l-NCS) 2 ]. The value of s is defined as the difference between the two largest donor-metal-donor angles divided by 60, a value which is 0 for the ideal square pyramid and 1 for the trigonal bipyramid [21].…”

“…Bond lengths O1-Cu1-S1 ii 90.8(2) N1-Cu1-S1 ii 84.4 (2) N2-Cu1-S1 ii 102.6(2) N4-Cu1-S1 ii 96.7 (2) Symmetry codes: hydrogen bonds, forming chains running along the c axis, as shown in Fig. 3.…”

“…Schiff bases prepared by the condensation of salicylaldehydes with primary amines are an important class of versatile ligands [1][2][3][4]. Transition metal complexes derived from such Schiff bases have been widely investigated due to their potential biological activities, especially the antimicrobial activity [5][6][7][8].…”