Copyright WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000 Angew. Chem. 2000 Supporting Information For Binding Cesium Ion with Nucleoside Pentamers. Templated Self-Assembly of an Isoguanosine Decamer.** Mangmang Cai, Allison L. Marlow, James C. Fettinger Daniele Fabris, Tamara J. Haverlock, Bruce A. Moyer, and Jeffery T. Davis* [*] Prof. J. T. Davis Department of Chemistry and Biochemistry University of Maryland, College Park College Park, MD 20742 (USA) 301-314-9121 (fax); jd140@umail.umd.edu
1. Crystallographic Experimental: A colorless crystal was cut along its prominent faces into a block with approximate dimensions 0.40 x 0.40 x 0.40 mm. The crystal was optically centered on the Bruker SMART1000 single crystal CCDdiffractometer. The crystal's initial unit cell parameters and crystal orientation matrix were determined from a leastsquares analysis of a random set of reflections collected via three sets (35 frames/set) of 0.3 wide ω-scans that were well distributed in reciprocal space. The intensity data were collected with 0.3 wide ω-scans (40 sec/frame), a crystal to detector distance of 9.0 cm, at two detector 2Θ settings (-15 and 35 ) thus providing a complete sphere of data to 49.4 in 2Θ with a 10 overlap between the two individual detector settings. The unit cell was then optimized using all of the frames from the initial series (606 frames) and used throughout the data reduction sequence. The SAINT+ 1 data reduction program, 2Θ max set to 47.5, was implemented to correct for Lorentz and polarization effects. An empirical absorption correction was applied to the 281,329 data (±h±k±l) with 92,549 unique [R(int)=0.0593] based upon equivalent reflection measurements using Blessing s method in the program SADABS 2. Zone images clearly indicated 2/m symmetry, not mmm symmetry, thus allowing XPREP 3 to eliminate the orthorhombic system and further check the data to indicate potential space groups. Since the molecules are chiral the most probably space group was P21 (no. 5) in two possible cell orientations with each possibility having its initial SHELX files generated. The structure was determined by direct methods using the program XS 4 and resulted in the successful location of many atoms comprising the two unique isog-decamer Cs units. Refinement was begun, using XL 5, and it became readily apparent that some form of disorder and/or twinning was additionally present. A TWIN 5 instruction, (100 0-10 00-1), was input and the refined structure began to converge with the twinning fraction found to be 0.412 (BASF 5 ). Countless least-square full-matrix refinement and difference-fourier map cycles were implemented to find the remaining non-hydrogen atoms and to additionally locate the solvent molecules. Atoms in close proximity to the central Cs + atoms, along with the Si atoms, were refined anisotropically. All others were refined isotropically. A disordered Si side chain, Si9a/Si9b, was also refined. Hydrogen atoms were placed in calculated positions. The
structure was refined to convergence [ /σ 0.001] with R(F)=10.39%, wr(f 2 )=22.72% and GOF=0.984 for all 92,533 unique reflections [R(F)=8.14%, wr(f 2 )=21.14% for those 69,614 data with Fo > 4σ(Fo)]. A final difference-fourier map possessed many residual peaks with the largest, within 1 Å of the heavy atoms, ρ 1.37 eå -3, while the remaining peaks were no larger than ρ 1.37 eå -3, indicating that the structure is both correct and complete. The function minimized during the full-matrix least-squares refinement was Σω(Fo 2- Fc 2 ) where ω=1/[σ 2 (Fo 2 ) + (0.1642*P) 2 + 0.0*P] and P=(max(Fo 2,0) + 2*Fc 2 )/3. An empirical correction for extinction was also attempted but found to be negative and therefore not applied. References: 1. Saint+ Data Reduction program. Bruker Analytical X-ray Systems. 2. (a) Blessing, R.H. Acta Cryst. (1995), A51, 33-38. (b) Sheldrick, G.M. SADABS Siemens Area Detector Absorption Correction ; Universität Göttingen, Germany, 1996. 3. Sheldrick, G.M., (1994). SHELXTL. Version 5.03. Siemens Analytical X-ray Instruments 4. Sheldrick, G.M., (1990). Acta Cryst. A46, 467-473. 5. Sheldrick, G.M., (1993). Shelxl-93 Program for the Refinement of Crystal Structures. University of Göttingen, Germany.
Table. Crystal data and refinement for (isog 1)10. Cs + Ph4B - Empirical formula C251 H372 B Cs N68.50 O50.75 Si10 Formula weight 5585.79 Temperature Wavelength Crystal system Space group 173(2) K 0.71073 Å Monoclinic P2(1) Unit cell dimensions a = 23.948(5) Å α= 90. b = 24.594(5) Å β= 90.015(3). c = 52.090(10) Å γ = 90. Volume 30680(10) Å 3 Z 4 Density (calculated) 1.209 Mg/m 3 Absorption coefficient 0.237 mm -1 F(000) 11854 Crystal size 0.40 x 0.40 x 0.40 mm 3 Theta for data collection 0.83 to 23.75. Reflections collected 281266 Independent reflections 92533 [R(int) = 0.0593] Completeness to θ= 23.75 99.8 % Absorption correction None Refinement method Full-matrix least-squares on F 2 Data/restraints/parameters 92533 / 43 / 4366 Goodness-of-fit on F 2 0.984 Final R indices [I>2σ(I)] R1 = 0.0814, wr2 = 0.2114 R indices (all data) R1 = 0.1039, wr2 = 0.2272 Absolute structure parameter -0.006(10) Largest diff. peak and hole 1.368 and -0.942 e.å -3
2. Electrospray Mass Spectral Experimental. Crystals of (isog 1)10. Cs + Ph4B - were dissolved in dry CHCl3. ESI spectra were collected using the first two sectors of a JEOL HX110/HX110 four sector mass spectrometer, equipped with a thermally assisted electrospray ion source (Analytica of Branford). Analyte solutions were infused into the source at a 1 ml/min flow rate using a syringe pump. The interfacing capillary was heated at 90 o C. Resolution was set to 1000 or higher by slit width adjustment. Mass accuracy was at least 175 ppm. Spectra were the averaged profile of 10-20 scans obtained with a scan rate of 90 s for the range 0-6000 m/z. High-resolution experiments on samples of (isog 1)10. Cs + (calc. avg. mw = 4508.62 Da, for a 175 ppm accuracy) produced isotopic peaks spaced by 1.0 m/z for the major species at m/z 4509.4, confirming a charge state of 1+.