Crystal structure of 4,4',6,6'-tetra(tert-butyl)-2,2'-[(1,4-butylene)dioxybis( nitrilomethylidyne)]diphenol, C34H52N2O4

Abstract

C34H52N2O4, monoclinic, P121/c1 (no. 14), a = 15.166(3) Å, b = 9.981(2) Å, c = 11.899(3) Å, b = 110.898(3)°, V = 1682.7 Å 3 , Z = 2, Rgt(F) = 0.068, wRref(F 2 ) = 0.227, T = 298 K. Source of materialTo an ethanol solution (10 ml) of 3,5-di(tert-butyl)-2-hydroxybenzaldehyde (236.7 mg, 1.00 mmol) was added an ethanol solution (3 ml) of 1,4-bis(aminooxy)butane (60.1 mg, 0.50 mmol). After the solution had been stirred at 55°C for 6 h, the mixture was filtered, washed successively with ethanol and ethanol/hexane (1:4), respectively. The isolated product was dried under reduced pressure and purified with recrystallization from ethanol to yield 133.8 mg of colorless crystalline solid (yield 48.4 %, m.p. 136-137°C). Block-like colorless single crystals of the title compound suitable for X-ray diffraction studies were obtained by slow evaporation of an acetone solution at room temperature. Elemental analysis found: C, 73.76 %; H, 9.67 %; N, 5.16 %; calc. for C34H52N2O4: C, 73.87 %; H, 9.48 %; N, 5.07 %. IR data are available in the CIF. DiscussionRecently, great attention was focused on N,N¢-bis(salicylidene)-ethylenediamine (salen) and its derivatives [1,2]. These compounds can easily form metallosalen complexes, and some of them show excellent catalytic activities for epoxidation and aziridination [3,4]. In addition, they are also used as models of reaction centers of metalloenzymes [5,6], and nonlinear optical materials [7]. Moreover, in biological and artificial systems allosteric regulation is effective in controlling molecular functions, such as molecular recognition and biological activity [8]. To improve such functions, chemical modifications of a basic salen skeleton are very interesting and important [9][10][11][12][13][14]. So, the introduction of some functional groups or substitution of some parts with appropriate ones are effective and inevitable. If an O-alkyl oxime moiety (-CH=N-O-(CH2)n-O-N=CH-) is used instead of (-CH=N-C-X-C-N=CH-) group, the large electronegativity of oxygen atoms is expected to affect strongly the electronic properties of N2O2 coordination sphere, which can lead to different and novel properties and structures of the resulted complexes. Thus, we have recently studied some novel salen-type bisoxime chelating compounds on the basis of O-alkyloxime instead of the imine moiety [13,14]. Here, we report another novel salen-type bisoxime chelating compound, which is sufficiently stable to resist scrambling of the C=N bonds.In the crystal structure of the title compound, the molecule adopts an conformation where the two salicylaldoxime moieties are apart from each other. The oxime groups and phenolic alcohols