Tsalen- and Tsalpn-Based Nickel Complexes with Two Aldehyde Functionalities as Potential Synthons for Thiophenolate-Containing Di- and Polynucleating Acyclic and Macrocyclic Ligands.

Abstract

Tsalen- and tsalpn-based nickel complexes with aldehyde functionalities have been prepared (tsalen = N,N'-ethylenebis(thiosalicylideneaminato)(2-) and tsalpn = N,N'-propane-1,3-diyl(thiosalicylideneaminato)(2-)). One of the complexes has been structurally characterized: Ni(pftp) (pftp = N,N-ethylene(6-formyl-4-methyl-2-methyliminatothiophenolato)(2-)) crystallizes in the monoclinic space group C2/c with a = 28.761(7), b = 8.582(2), c = 7.841(4) Å; beta = 98.92(3) degrees, and Z = 4. Ni(pftp) and Ni(eftp) (efpt = N,N-ethylene(6-formyl-4-methyl-2-methyliminatothiophenolato)(2-)) were used as synthons for acyclic and macrocyclic complexes and a prototype of each has been structurally characterized. The Schiff base derivative of Ni(pftp) and 2-(2-aminoethyl)pyridine gives the acyclic complex, Ni(peptp) (peptp =N,N-propane-1,3-diyl(6-(N-(2-ethylpyridyl)iminomethyl)-4-methyl-2-methyliminatothiophenolato)(-)) with the two ethylpyridyl arms furnishing an "open site", which in this complex is vacant, and a "closed site", in which the Ni(2+) is located. Ni(peptp) crystallizes in the monoclinic space group P2(1)/n with a = 10.247(7), b = 21.886(8), c = 15.662(9) Å; beta = 92.58(6) degrees, and Z = 4. Schiff base condensation of Ni(pftp) with diaminopropane gave two different macrocyclic dinickel complexes [L(1)Ni(2)](ClO(4))(2) and L(2)Ni(2). L(1) and L(2) are the 2 + 2 and 4 + 4 macrocycles, respectively, comprising two propylenediamine and two thiocresol units and four propylenediamine and four thiocresol units, respectively. Crystals of L(2)Ni(2) (L(2) = (10,23,36,49-tetramethyl-13,26,39,52-tetramercapto-2,6,15,19,28,32,41,45-octaaza-1,7,14,20,27,33,40,46-octaene[7.7.7.7]metacyclophane) are of poor quality and crystallize in the C2/c space group with a = 31.517(14), b =8.980(2), c = 26.822(12) Å; beta = 117.17(2) degrees, and Z = 4.