Synthesis and Characterization of some Unsymmetrical Schiff Base Ligands and their Nickel(II) Complexes Incorporating o‐Phenylenediimine Units

Abstract

Six new nickel(II) complexes of the unsymmetrical Schiff base ligands derived from o-phenylenediamine were synthesized. These complexes were prepared by template and non-template reactions of the precursor 3-acetyl-4-[N-(2'-aminophenyl)-amino]-3buten-2-one (HL°) with appropriate o-hydroxycarbonyl aromatic compounds, aromatic 1,3-oxo aldehydes and 1,3-diketones. The nickel(II) compounds were characterized by analytical and spectroscopic methods. Crystal structure of complex [3-acetyl-(6,7)benzo-8-salicylidene-5,8-diazahepta-3-ene-2-onato(2-)]nickel(II) (NiL 1 ) has been determined by X-ray powder diffraction method, Die Synthese und Charakterisierung einiger unsymmetrischer Schiff-Basen als Liganden und deren Nickel(II)-Komplexe mit o-Phenylendiamin-FragmentenInhaltsübersicht. Sechs neue Nickel(II)-Komplexe der unsymmetrischen Schiff-Basen als Liganden wurden synthetisiert. Diese Komplexe wurden mittels Template-und Nicht-template-Reaktionen aus 3-Acetyl-4-[N-(2'-aminophenyl)-amino]-3-buten-2-on (HL°) und entsprechenden aromatischen o-Hydroxykarbonylverbindungen, aromatischen 1,3-Oxoaldehyden und 1,3-Diketonen dargestellt. Die Nickel(II)-Verbindungen wurden mit Hilfe analytischer und spektroskopischer Methoden charakterisiert. Kristallstrukturbestimmung des Komplexes [3-Acetyl-(6,7)benzo-8-salicylidene-597 revealed that the molecules are almost flat, and there are no forces other than van der Waals interactions between molecules. The structure was solved by global optimisation technique and refined by the Rietveld method, obtained R F and R wp are 11.6 and 17.4%, respectively. The synthesis of a new unsymmetrical nickel(II) tetraazamacrocyclic complex is also described. Keywords: Schiff bases; Nickel; Macrocyclic complex; X-ray powder diffraction; NMR spectroscopy 5,8-diazahepta-3-en-2-onato(2)]nickel(II) (NiL 1 ) erfolgte mit Röntgen-Pulverdiffraktometrie und bestätigte, daß die Moleküle fast eben sind und zwischen ihnen keine andere als van der Waals-Wechselwirkungen bestehen. Die Strukturanalyse wurde mit der Technik globaler Optimierung durchgeführt und mit der Rietveld-Methode verfeinert, die erhaltenen R F -und R wp -Werte sind 11,6 und 17,4 %. Die Synthese eines neuen unsymmetrischen Nickel(II)tetraaza-makrozyklischen-Komplexes wird beschrieben.

New unsymmetrical Schiff base Ni(ii) complexes as scaffolds for dendritic and amino acid superstructures

“…Complexes 3D 3 -3D 5 and 4D 3 -4D 5 (general procedure). A solution of complex 3 or 4 (1 mmol), the mesylate of the appropriate poly(arylether) dendron (D n -OSO 2 Me; 2 mmol), [18]-crown-6 (1 mmol) and K 2 CO 3 (2 mmol) in anhydrous acetone (20 ml) was vigorously stirred and refluxed under argon for 12 h. After the solvent was evaporated under reduced pressure, the residue was treated with a small quantity of water (10 ml) and extracted three times with dichloromethane (30 ml). Organic layers were collected, dried with anhydrous MgSO 4 and evaporated to dryness.…”

“…3,4 Much less attention has been focused on unsymmetrical Schiff bases derived from 1,2-diamines, salicylic aldehyde and b-diketones. [5][6][7][8][9][10][11][12][13][14][15][16] In particular, those derived from aromatic 1,2-diamines have been relatively under-investigated 17,18 and are not yet sufficiently appreciated in the synthesis of advanced materials. It is worthwhile to mention here that unsymmetrical Schiff bases of this type seem to be of practical importance in synthesis as systems allowing the independent use of reactive centres located in their substratebased fragments.…”

Structural Studies of β‐Cyclodextrin and Permethylated β‐Cyclodextrin Inclusion Compounds of Cyclopentadienyl Metal Carbonyl Complexes

“…In this paper, we use conventional powder X‐ray data, in combination with the technique proposed by Caira, to produce a hypothetical structural model of the inclusion compound TRIMEB · [CpMo(CO) 3 Cl], obtained by global optimisation using simulated annealing. The calculations were performed using the recently developed FOX program,20,21 which has proven to be a reliable, fast and robust software package for the solution of many different types of compounds 22–26. This kind of ab initio model idealisation is unusual among compounds typically composed of light atoms (such as carbon, hydrogen and oxygen), and, to the best of our knowledge, is completely unprecedented among cyclodextrin inclusion compounds.…”