Characterization and crystal structure of a 17-membered macrocyclic Schiff base compound MeO-sal-pn-bn

Abstract

UDC 548.737The reaction of 1,4-diaminobutane with 2,2′-diformyl-6,6′-dimethoxy-diphenoxypropane in a mixed solvent of methanol and chloroform results in a new 17-membered macrocyclic Schiff base compound MeO-sal-pn-pn. The title compound is characterized by the elemental analysis (CHN), FT-IR, 1 H NMR spectroscopy, and powder X-ray diffraction. The crystal data are: M r = 396.5, orthorhombic, P2 1 2 1 2 1 , with unit cell parameters: a = 4.71769(3) Å, b = 19.1524(2) Å, c = 22.9418(2) Å, V = 2072.90(3) Å 3 , and Z = 4.The macrocyclic Schiff base compounds and their transition metal complexes play a key role in coordination chemistry [1][2][3][4][5]. They are extensively studied for their capacity to bind and transport metal ions, for the possibility to act as models for metalloproteins [6,7]. and for their role in host-guest and supramolecular chemistry [8][9][10]. Macrocycles containing imine groups can form mono-, di-, and polynuclear transition metal complexes with various applications [11][12][13][14]. Among them a wide Schiff base macrocycles based on 2,6-diacetylpyridine and 2,6-diformylpyridine as building blocks evolved from the early studies [15].Many synthetic methods for the preparation of Schiff base macrocyclic compounds use transition metal ions as templating agents [16][17][18][19][20][21]. However, this method yields stable macrocyclic complexes, thus making the preparation of a metal free ligand difficult [16][17][18][19][20][21]. Therefore, during the last decade, considerable effort has been made to develop metal free methods for the preparation of Schiff base macrocyclic compounds [15,[22][23][24]. Recently, many compounds in this field have been rapidly developed and studied [25]. Herein, we report the synthesis, characterization, and crystal structure of a 17-membered [1+1] macrocyclic Schiff base compound MeO-sal-pn-bn obtained by the condensation of 1,4-diaminobutane with 2,2′-diformyl-6,6′-dimethoxy-diphenoxypropane in a mixed solvent of methanol and chloroform (1:1 v/v) (Scheme 1).

Crystal structure of (bis(2,2′-bipyridine-κ 2 N,N′))-(3,5-dinitrosalicylato-κ 2 O,O′)nickel(II), C27H18N6NiO7

“…Complexs with salicylato and N-donor ligands, were found to display diverse structure types [1][2][3]. A large number of hydrogen-bonded supramolecular architectures based on bipyridine and carboxylato ligands have been reported [4].…”

FOX, Current State and Possibilities

“…An interesting example where the usage of the MD approach was crucial is the crystal structure of the 17-membered cyclic Schiff base [33]. According to the volume of the orthorhombic unit cell Modelling of the orientation disorder of rigid fragments (closo-borane in our example where the disorder is dynamical and supporting cation mobility) is simplified in FOX by Dynamical Occupancy Correction (DOC) [1], which also takes into account the point symmetry of the Wyckoff site where the fragment is localized.…”

“…An interesting example where the usage of the MD approach was crucial is the crystal structure of the 17-membered cyclic Schiff base [33]. According to the volume of the orthorhombic unit cell (a = 4.71769(3), b = 19.1524 (2), c = 22.9418(2) Å, V = 2072.90(3) Å 3 ), and the fact that the systematic extinctions satisfying P2 1 2 1 2 1 space group, the asymmetric part of the unit cell contains only one molecule of the Schiff base (Z = 4) with 21 DoF.…”