O O N O O O N O O OH N O OH 1 MeO OMe MeO OMe 2 3 188 J. CHEM. RESEARCH (S), 1997 J. Chem. Research (S), 1997, 188–189 J. Chem. Research (M), 1997, 1237–1251 The X-Ray Crystal Structures of Two Derivatives of 2,6-Bis{[2-(dimethoxymethyl)phenoxy]methyl}pyridine Harry Adams, David E. Fenton,* Yuh-Shan Ho, Blanca A. Najera and Cecilia O. Rodriguez de Barbarin Department of Chemistry, Dainton Building, The University of Sheffield, Sheffield S3 7HF, UK The X-ray crystal structures of 2,6-bis{[2-dimethoxymethyl)phenoxy]methyl}pyridine and 2,6-bis{[2-(hydroxymethyl)- phenoxy]methyl}pyridine are reported.We have previously reported that the reaction of 2,2p- [pyridine-2,6-diylbis(methyleneoxy)]dibenzaldehyde (1) and bis(2-aminoethyl) ether, in the presence of barium cations as a templating device, can yield a [1+1] macrocyclic Schiff base.1 Reaction of this macrocycle with cerium nitrate led to the isolation of the complex [Ce(1)2](NO3)3 .2H2O, hydrolysis of the macrocycle having occurred.2 Consequently we have investigated the potential complexation properties of 1 towards the lanthanides3 and have shown that whilst [Ce(1)2](NO3)3 .2H2O can be formed by the reaction of cerium nitrate with 1 in a mixed methanol–acetonitrile medium a very different white crystalline product is formed when the reaction is carried out in methanol alone.Spectroscopic analysis of this product suggested that acetal formation had occurred to give 2,6-bis{[2-(dimethoxymethyl)- phenoxy]methyl}pyridine (2), as we had previously noted in the reaction of 1 with lead(II) salts.1 Recrystallisation of 1 from methanol alone gave no acetal formation, suggesting that 2 is produced as a result of a metal ion activated reaction. A single crystal X-ray crystal structure determination con- firmed the nature of 2 (Fig. 1). The bond angles and distances in the ligand are comparable to those reported for the related compound, pyridine-2,6-dimethanol.7 Crystal Data for 2.·C25H29NO6, Mr=439.49, colourless oblong crystals from methanol, crystal dimensions 0.66Å 0.44Å0.25 mm, monoclinic, a=9.609(3), b=9.327(2), c=26.101(3) Å, b=96.101(2)°, U=2326.0(9) Å3, Z=4, Dc=1.255 g cmµ3, space group P21/n, Mo-Ka radiation (�l =0.71069 Å), m(Mo-Ka)=0.90 cmµ1, F(000)=936.Three-dimensional, room temperature X-ray data were collected in the range 3.5s2ys45° on a Siemens P4 diffractometer by the omega scan method. Of the 4186 reflections measured, all of which were corrected for Lorentz and polarisation effects (but not for absorption), 2250 independent reflections exceeded the significance level |F|/s(|F|)a4.0.The structure was solved by direct methods and refined by full matrix least squares on F2. Hydrogen atoms were included in calculated positions and refined in riding mode. Refinement converged at a final R=0.0571 (wR2=0.1700, for all 3024 data, 289 parameters, mean and maximum d/s 0.000, 0.000), with allowance for the thermal anisotropy of all non-hydrogen atoms.Minimum and maximum final electron density µ0.312 and 0.390 e ŵ3. A weighting scheme w=1/[s2(Fo2)+(0.0895P)2+1.1610P] where P=(Fo2+2Fc2)/ 3 was used in the latter stages of refinement. Complex scattering factors were taken from the program package SHELXL935 as implemented on the Viglen 486dx computer. The structure of 2 may be compared with that of the dialcohol, 2,6-bis{[2-(hydroxymethyl)phenoxy]methyl}pyridine (3) (Fig. 2), prepared by reduction of 1 using NaBH4.5 The dialcohol is isolated as the monohydrate 3.H2O, and the water molecule helps augment three dimensional molecular aggregation, bridging adjacent molecules of 3 by hydrogen bonding to a pyridine nitrogen atom from one molecule and to an alcoholic oxygen atom from an adjacent molecule. Crystal Data for 3. H2O.·C21H23NO5, Mr=369.42, pale yellow prismatic crystals from acetonitrile, crystal dimensions 0.25Å0.85Å0.08 mm, triclinic, a=11.222(4), b=11.308(4), c=7.588(9) Å, a=81.277(12)°, b=105.718(20)°, g= 87.139(6)°, U=912.0(11) Å3, Z=2, Dc=1.350 g cmµ3, space group P�1 (C1i , no. 2), Mo-Ka radiation (�l =0.71069 Å), m(Mo-Ka)=0.90 cmµ1, F(000)=391.95. The experimental data were collected at room temperature in the range 6.5s2ys50.0° on a Stoe Stadi 2 diffractometer by the omega scan method (h from µ15 to 15, k from µ15 to 15, l from 0 to 8). The 1575 independent reflections (of 3187 measured) for which I/s(I)a3.0 were corrected for Lorentz and polarisation effects but not for absorption.The structure was solved by direct methods. Hydrogen atoms were detected and *To receive any correspondence. Fig. 1 X-Ray crystal structure of 2 Fig. 2 X-Ray crystal structure of 3J. CHEM. RESEARCH (S), 1997 189 placed in calculated positions and refined in riding mode with isotropic thermal vibrational parameters related to those of the supporting atoms. One of the alcoholic H atoms was found to be disordered between sites with necessarily equal population.These hydrogens were constrained with an O·H distance of 1.00 Å and refined in riding mode. Refinement by block cascade least-squares methods converted to a final R of 0.0516 (Rw=0.0595) for 244 parameters, with allowance for thermal anisotropy of all non-hydrogen atoms. A weighting scheme wµ1=[s(2(F)+0.0035 F2] was used in the final stages of refinement. The maximum value of d/s in the final cycle was 0.009 (mean value 0.001).The final difference electron density map showed maximum and minimum of 0.194 and µ0.221 e ŵ3. Complex scattering factors were taken from the program package SHELXTL6 as implemented on the Data General DG30 computer. We thank the EPSRC and the Royal Society for funds towards the purchase of the diffractometer and CONACYT for support to B. A. N. and C. O. R. Techniques used: X-ray diffraction References: 7 Figures: 3 Tables 1 and 3: Atomic coordinates and equivalent isotropic displacement parameters for 2 and 3 respectively Tables 2 and 4: Bond lengths (Å) and bond angles (°) for 2 and 3 respectively Tables 5–8: Anisotropic displacement parameters, hydrogen coordinates and isotropic parameters Received, 30th January 1997; Accepted, 21st January 1997 Paper E/7/00690J References cited in this synopsis 1 H.Adams, N. A. Bailey, R. Bastida, D. E. Fenton, Y.-S. Ho and P. D. Hempstead, J. Chem. Res., 1992, (S) 190; (M) 1501. 2 H. Adams, C. O. Rodriguez de Barbarin, D. E. Fenton, Y.-S. Ho and G. J. Humber, Inorg. Chim. Acta, 1995, 232, 227. 3 B. A. Najera, unpublished results, 1996 5 G. M. Sheldrick, SHELXL93 Program for crystal structure refinement, University of Gottingen, Germany, 1993. 6 G. M. Sheldrick, SHELXTL, An integrated system for solving, refining and displaying crystal structures from diffraction data (Revision 5.1), University of Gottingen, Germany 1985. 7 W. Bell, P. I. Coupar, G. Ferguson and C. Glidewell, Acta Crystallogr., Sect. C, 1996, 52,