Crystal Structure and Properties of a New 2,2’-Ortho(metaxylene) E-Bridged
Stilbenophane
Maryam Mirza-Aghayan
*
, Hossein Reza Darabi, Laleh Ali-Saraie, Mitra Ghassemzadeh, Mohammad
Bolourtchian
Tehran/Iran, Chemistry and Chemical Engineering Research Center of Iran (CCERCI)
Mehdi Jalali-Heravi
Tehran/Iran, Department of Chemistry, Sharif University of Technology
Bernhard Neumüller
Marburg/Germany, Fachbereich Chemie der Universität
Received September 20th, 2001.
Abstract. The synthesis and characterization of novel E and Z-2,2’-
ortho(metaxylene)-bridged stilbenophane 2 by reductive McMurry
condensation are described and the X-ray structure determination
of the E-isomer is reported. The structure analysis of 2-E shows
weak hydrogen bonding. The complexation of Na
1
ions in 2,2’-
Die Kristallstruktur und Eigenschaften eines neuen 2,2’-Ortho(metaxylol)-E-
verbrückten Stilbenophans
Inhaltsübersicht. Vorgestellt wird die Synthese und Charakterisi-
erung der neuen E- und Z-2,2’-Ortho(metaxylol)-verbrückten Stil-
benophane 2 durch reduktive McMurry-Kupplung; das E-Isomer
wurde zusätzlich mittels Röntgenstrukturanalyse untersucht. Da-
nach wird die Konformation im Festkörper durch schwache inter-
1 Introduction
Stilbenophanes constitute an important class of organic
chemistry for their application in material science as optical
brighteners, laser dyes, optical recording media, photores-
ists, photoconductors, light emitting diode and nonlinear
optics [1]. The crown ether stilbenophanes [2] with novel
structures and properties attract considerable attention es-
pecially in host-guest and molecular recognition chemistry
[3].
In this paper we wish to report the synthesis of the novel
2,2’-ortho(metaxylene)-E-bridged stilbenophane using
McMurry reaction [4]. The synthesized compound contains
the shortest and most rigid briding moiety in the class of
stilbenophanes crown ether. The compound is characterized
by NMR, IR spectroscopy and its crystal structure is deter-
* Dr. Maryam Mirza-Aghayan
Chemistry and Chemical Engineering Research Center of Iran
P.O. Box 14335-186
Tehran (Iran)
E-Mail: M.Mirzaaghayan@ccerci.ac.ir
Z. Anorg. Allg. Chem. 2002, 628,6812684 WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 004422313/02/628/6812684 $ 17.501.50/0
681
ortho(metaxylene)-Z-bridged stilbenophane using sodium chloride
and measurements of conductivity were performed. The formation
constant logK was determined to 1.45.
Keywords: Stilbenophanes; Hydrogen bonds; Crystal structure
molekulare Wasserstoff-Brückenbindungen stabilisiert. Die Kom-
plexierung von Na
1
-Ionen in 2-Z wurde durch Konduktometrie
verfolgt und die Komplexbildungskonstante logK zu 1,45 be-
stimmt.
mined by an X-ray analysis, respectively. In addition AM1
calculation, cyclic voltammetry and complexation of the
compound 2-Z with Na
1
ions using NaCl were studied.
2 Synthesis and Characterization of 2
Compound 2 was made in 61 % overall yield from salicylal-
dehyde and α,α’-dibromo-m-xylene [6] (Scheme 1). There-
fore, salicyladehyde was treated with sodium hydroxide in
THF/HMPA (1:1) at room temperature and the solution
was refluxed for further 1 h. The α,α’-dibromo-m-xylene
was added to the solution and it was refluxed for additional
2hrs,togive1 in excellent yield. A solution of 1 in dry
toluene was added dropwise to a suspension of low-valent
titanium reagent (prepared from titanium tetrachloride and
zinc powder (1:2) in boiling dry THF/toluene), at room
temperature under argon atmosphere. The reaction mixture
was refluxed for further four hours to give the desired com-
pound 2 (61 % yield) as a mixture of the E- and Z-isomers
(E:Z 5 25 %:37 %; isolated product). By using dry THF as
solvent, only the 2-Z isomer can be obtained, selectively
(10 %).