1166 Inorgmic Chemistv, Vol. 12,No. 5, 1973
Terzis, Heauchamp, and Rivest Contribution from the Department of Chemistry, University of Montreal, Montreal, Quebec, Canada
Molecular Structure of nine-diaquodicopper(I1) Perchlorate Dihydrate, 5 )4(H20)21(@104)4 ' 2 H 2 0 A. TERZIS, A. L. BEAUCHAMP, and R. RIVEST* Received September 14, I9 72 The crystal and molecular structure of the title compound has been determined from three-dimensional X-ray data. The structure was solved by the standard heavy-atom method and refined by least-squares procedures to a conventional R of 0.046 for 2420 observed reflections. The purple complex crystallizes in the monoclinic space group P2, /c and the cell dimensions are R = 12.212 (6), b = 12.240 (6), c = 17.635 (9) A, p = 130.27 (3)', and V = 2011.3 A 3 . The four Cu(C,H,N & z units in the cell pair up to form two centrosymmetric dimeric ions, in which adenine acts as a bridging bidentate ligand. Each copper atom is surrounded by four nitrogen atoms (at 2.00-2.04 A) from four different adenine molecules and by the oxygen atom (at 2.166 A) of a water molecule. The geometry around copper may be described as a tetragonal pyramid. The four basal nitrogen atoms are coplanar, but the copper atom is displaced from that plane by 0.269 A toward the apical water molecule. The large Cu-Cu separation (2.951 A) is not considered to be consistent with significant metalmetal bonding.
Introduction Experimental Section The importance of metal ions in nucleic acid processes has Crystal Data. A sample of the compound was kindly supplied by Boivin and Z a d ~ r . The ~ purple crystals are stable to air and to now been recognized and their involvement in these procX-rays. The reciprocal lattice symmetry 2/m observed from preesses has received considerable attention. They have proliminary precession photographs indicated that the crystals are monofound effects on the structure and function of nucleic acids clinic. Systematic absences, occuring for h01 reflections when 1 = and their constituents. They alter the coding specificity of 2n + 1 and for OkO reflections when k = 2n + 1 are consistent only with space group P2,/c. The cell parameters were calculated by polynucleotides acting as templates for protein synthesis' least-squares refinement of the setting angles of 12 automatically and are required for stabilizing the structure of tRNA.2 centered reflections (Cu Kp radiation, h 1.39217 A, 50" < 20 < Model studies with DNA and its constituents have indicated 63"): u = 12.212 (6), b = 12.240 (6), c = 17.635 (9) A, p = that the ordered structure of the double helix is stabilized 130.27 (3)", V = 2011.3 A3, and calculated density of 1.876 g cm-3 by some metal ions (Mg", Na') and destabilized by other units per cell. The density measured for Z = 4 C,,H,,N,,Cl,O,,Cu by flotation in a mixture of tetrabromoethane and chloroform at metal ions (Cu2*,Cd2+,Pb"). 23" is 1.88 f 0.01 g ~ m - ~The . esd's of the cell parameters are asIn this paper, we report on the crystal structure of a 1: 2 signed twice the values computed in the least-squares refinement, copper perchlorate-adenine (AdH) complex. Our primary which reflects our experience with reproducibility of results. interest was the binding sites of the metal to the base in this There was a small but significant difference between the cell parameters obtained at the beginning and at the end of data colleccompound. In [ C U ( A ~ H ~ ) ~ Bonly ~ ~N9 ] Bwas ~ ~found , ~ to The coordinate to copper, whereas in [ C U ~ ( A ~ H ) ~ C ~ ~ ] C ~ ~tion. *~H ~ average O ? values reported above were used to calculate the bond distances and bond angles. The same calculations were done [Cu$ls(AdH&] *4H20,5and [ C U ~ A ~ ~ ( H.6H20,6 ~O)~] as well with the two extreme sets of cell parameters. This changed adenine acts as a bridging bidentate ligand via both N 3 and the Cu-Cu distance by l u , but the other bond lengths and angles 1\19. The latter mode of binding is observed for adenine in were affected by less than 0.50. Collection and Reduction of Intensity Data. The intensity data the present compound. were collected from a well-formed crystal of dimensions 0 14 X This work was also expected to provide information on 0.18 XO.11 X 0.09 mm (perpendicular to the {loo}, {Oll}, {llr}, the structural changes induced in the ligand molecule by the and { 111) faces, respectively). The crystal was mounted on a metal. This point is particularly relevant to the interpretaPicker FACS-1 four-circle automatic diffractometer with its c axis along the 9 axis of the instrument. Ni-filtered Cu Kor radiation tion of nmr line-broadening experiments. Indeed, the sugwas used and the takeoff angle was 4'. The source-to-cryqtal distance gestion has been made,7 and subsequently challenged,8 that was 16 cm and the crystal-to-counter distance was 35 cm. The data metal ions binding at one site distort the electronic configurawere collected with the 8-20 scan technique, at a scan rate of l"(20)/ tion of the whole molecule, so that broadening could occur min. The scan range was 1.7" applied symmetrically to the calculated 20 value. A dispersion factor of 114.6Ah/h, where Ah is the at sites far removed from the metal. Previous X-ray work on difference between h(Ka,) and h(Ka,) and h is h ( K Z ) , was added to copper-adenine complexes failed to provide meaningful inthe high side of 28 to allow for the separation of the orl az doublet. formation because of disorder or relatively large uncertainty Stationary-counter, stationary-crystal background counts of 40 sec on the ring bond lengths and angles. were taken at each limit of the scan range. During the course of the ( 1 ) W. Szer and S. Ochoa, J. Mol. Biol., 8 , 823 (1964). (2) J. R. Fresco, A. Adams, R. Ascione, D. Henley, and T. Lindahl, ColdSpring Harbor Symp. Quant. Biol., 31, 527 (1966). (3) P . De Meester, D. M. L. Goodgame, K. A. Price, and A. C. Skapski, Biochem. Biophys. Res. Commun., 44, 5 10 (1971). (4) P. De Meester and A. C. Skapski, J. Chem. SOC.A , 2 167 (1971).
(5) P. De Meester, D. M. L. Goodgame, K. A. Price, and A. C. Skapski, Chem. Commun., 1573 (1970). ( 6 ) E. Sletten, Acta Crystallogr.,Sect. B, 25, 1480 (1969). (7) J . A. Carrabine and M. Sundaralingam, J. Amer. Chem. SOC., 9 3 , 369 (1970).
(8) N. A. (1971).
Bergei and G. L. Eichhorn, Biochemistry,
10, 1847
data collection, three standard reflections were measured at a period of 30 reflections. Their variations were less than 2% from their respective means. A total of 4061 measurements were made in the region of 20 < 120" and reduced to a set of 2957 independent reflections, after averaging the equivalent ones and taking out 170 systematically absent reflections. The integrated intensity was calculated as [(net) = Z(scan) - K ( B , + B,), whereZ(scan) is the count over the scan range, B , and B , are the background counts, and K is the ratio of the (9) The crystals were isolated from a water solution containing adenine (0.015 M ) and Cu(ClO,), (0.005 M ) at pH 4.0. They are undoubtedly identical with those prepared by R. Weiss and 14. Venner, Z. Physio2. Chem., 341, 229 (1965), and formulated as [(C,H5N,),Cu](C1O,),~1.5H,O.
Inorganic Chemistry, Vol. 12, No. 5, 1973 1167
[Cu2(C~H5N5)4(Hz0)21(C104)4'2H*0 Table XI. Final Structure Parameteisa and Estimated Standard Deviationsb Atom X Y z 104Pli cu c11 c12 01 02 03 04 05 06 07 08 09 010 N1
c2 N3 c4
c5 C6 N7 C8 N9 N10 N1* c2* N3 * c4 * c5* C6 * N7* C8* N9* N10*
0.04989 (6) 0.48869 (15) 0.85132 (12) 0.3827 (4) 0.5198 (8) 0.4449 (6) 0.6166 (5) 0.9211 (5) 0.9414 (6) 0.7255 (5) 0.8188 (6) 0.1024 (3) -0.1390 (8) -0.2913 (4) -0.1696 (5) -0.1322 (3) -0.2298 (4) -0.3612 (5) -0.3951 (5) -0.4291 (4) -0.3387 (5) -0.2173 (3) -0.5205 (4) 0.2870 (4) 0.2255 (5) 0.1481 (4) 0.1361 (4) 0.1960 (4) 0.2728 (4) 0.1573 (4) 0.0794 (5) 0.0639 (3) 0.3309 (4)
Hydrogens HC2 HN7 HC8 HlNlO H2N10 H109 H209
x
-0.101 -0.512 -0.363 -0.532 -0.583 0.178 0.052
(4) (5) (5) (5) (5) (5) (5)
0.11405 (5) 0.37621 (14) 0.0028 (1) 0.3488 (5) 0.4863 (5) 0.3428 (4) 0.3181 (7) 0.0895 (3) -0.0375 (5) 0.0491 (6) -0.0811 (4) 0.2861 (3) 0.4221 (6) 0.2465 (3) 0.2279 (4) 0.1355 (3) 0.0546 (4) 0.0676 (4) 0.1676 (4) -0.0311 (3) -0.0984 (4) -0.0494 (3) 0.1895 (3) 0.1072 (3) 0.1355 (4) 0.0715 (3) -0.0324 (3) -0.0683 (3) 0.0045 (4) -0.1771 (3) -0.2009 (4) -0.1152 (3) -0.0224 (3) Y 0.295 (3) -0.045 (4) -0.176 (4) 0.260 (4) 0.133 (4) 0.316 (4) 0.323 (4)
0.02854 (4) 0.19790 (9) 0.22057 (9) 0.2049 (3) 0.2123 (5) 0.1045 (3) 0.2738 (4) 0.2128 (4) 0.3177 (3) 0.1943 (5) 0.1541 (4) 0.0450 (2) -0.0746 (5) 0.0104 (3) 0.0276 (3) 0.0093 (2) -0.0273 (3) -0.0506 (3) -0.0335 (3) -0.0856 (3) -0.0819 (3) -0.0470 (2) -0.0549 (3) 0.3431 (2) 0.2504 (3) 0.1691 (2) 0.1886 (3) 0.2821 (3) 0.3622 (3) 0.2697 (2) 0.1729 (3) 0.1207 (2) 0.4550 (3) z 0.055 -0.112 -0.106 -0.048 -0.087 0.078 0.019
(3) (3) (4) (4) (4) (3) (4)
60.1 (6) 143 (2) 93 (1) 136 (6) 526 (17) 324 (9) 152 (7) 202 (7) 291 (10) 117 (6) 316 (10) 107 (4) 422 (14) 102 (5) 97 (6) 73 (4) 57 (5) 88 (6) 103 (6) 68 (4) 80 (5) 63 (4) 105 (5) 103 (5) 103 (6) 70 (4) 6 1 (5) 63 (5) 70 (5) 96 (5) 95 (6) 68 (4) 126 ( 5 ) B, A' 1.7 (8) 3.5 (10) 3.9 (11) 4.5 (12) 4.8 (13) 3.2 (10) 4.0 (11)
38.1 (4)
1o4Pl2
1O4Pi3
20.7 (3) 0.4 (4) 43.5 it$ -68 ( i j 42.4 (7) 0.6 (9) 85 (3) -61 (5) 190 (7) -190 (8) 44 (2) -53 (5) 14 (7) -23 (4) 77 (7) 22 (6) -42 (5) -18 (3) 125 (8) -5 (3) -3 (3) 8 (3) 6 (3) 7 (3) 12 (4) -12 (3) -5 (4) 0 (3) 22 (3) -11 (3) -9 (3) -2 (3) 3 (3) -4 (3) -2 (3) -1 (3) -9 (3) 2 (3) 25 (2) -14 (3)
54 (3)
Hydrogens HC2* HN7* HC8* HlN10* H2N10* HlOlO
a The anisotropic thermal parameters are in the form exp(-h2pll - k'p,, given in parentheses. Identifiers with an asterisk refer to adenine molecule 2.
total scan time to the total background time. A reflection was considered as observed whenI(net) = >8 and >O.lK(Bi + B z ) . By these criteria, 2420 reflections were retained. An absorption correction based on the equations of the crystal faces was applied to each reflection. The transmission factors calculated with the linear absorption coefficient of 47.0 cm-' for Cu Kor radiation ranged from 0.58 to 0.70. Finally, the Lorentz and polarization corrections were applied. Solution and Refinement of the Structure. The structure was solved by the standard heavy-atom method and refined by fullmatrix least squares initially and by block-diagonal least squares in the later stages. The copper position was evident from the threedimensional Patterson map. A Fourier synthesis phased on this position revealed the positions of 14 additional atoms. These positions were refined and the next Fourier synthesis revealed all nonhydrogen atoms. Refinement proceeded normally using the block-diagonal least-squares approximation and converged initially at a n R , (=ZllFol- IFcII/.ZIFoI) of 0.105, after varying the positional and individual isotropic temperature factors for all nonhydrogen atoms. Inclusion of anisotropic temperature factors reduced R , t o 0.053. At this stage, a secondary extinction correction was entered. A difference map showed ten peaks of 0.5-0.7 e/A3, suggesting positions for the hydrogens of the adenine ligands. Inclusion of these positions in the refinement reduced R , t o 0.047. A series of three difference maps with data limited to (sin O)/h = 3o(Fo2). The molecular structure consists of a six-membered ring of alternating Cu atoms and bridging S atoms which is bisected by a crystallographic mirror plane. The ring is puckered into a chair conformation with equatorial (CH,),P groups, and the phosphine sulfide is symmetrically bridged. The copper atoms are three-coordinate, with approximately trigonal-planar coordination to two bridging S atoms of the phosphine sulfides and one terminal chlorine atom. The bond angles about the S and P atoms are nearly tetrahedral. Important bond distances follow: Cu-S, 2.265 (1) A ; Cu-Cl, 2.209 (2) and 2.220 ( 1 ) A ; S-P, 2.025 (1) A .
Introduction While investigating the coordination properties of phosphine sulfide ligands with copper(I), we found that the preferred coordination number is apparently 3 rather than 2 or 4.' In fact, the X-ray structure determination of [Cu((CH3)3PS)3] C104 showed that the cation contained a trigonalplanar arrangement of sulfur atoms around the copper atom.3 Another class of compounds, [CuLX] (X = C1, Br, I, SCN; L = tertiary phosphine sulfide), has recently been i ~ o l a t e d . ~On the basis of their relative insolubilities, we assumed that these compounds were polymeric. For the complexes [Cu((CH&PS)XIn (X = C1, Br, I) the shift of the P-S stretching frequency upon coordination of (CH&PS (as (1)(a) Ohio State University Postdoctoral Fellow, Sept 1971Sept 1972. (b) Postdoctoral Research Associate. (2)J . A. Tiethof, A. T. Hetey, P. E. Nicpon, and D. W. Meek,
Inorg. Nucl. Chem. Lett., 8 , 841 (1972). (3) P. G. Eller and P. W. R. Corfield, Chem. Commun., 105 (1971). (4)J . A. Tiethof, A. T. Hetey, and D. W. Meek, to be submitted
for publication.
observed from their infrared spectra) was twice as large as the shift for [Cu((CH3)3PS>,] Clod (40-45 and 25 cm-', respectively). The larger shift of the P-S infrared absorption in the halide complexes was attributed to sulfur atom bridges: even though few bridging phosphine sulfides have ever been proposed.' The X-ray structural determination of [Cu((CH3)3PS)C1]3, which is reported herein, was undertaken to clarify (1) the nature of the polymer, (2) the bridging atom, and (3) the coordination number and geometry of copper(1) in this compound. To our knowledge this is the first X-ray determination of the structure of a complex involving a bridging phosphine sulfide ligand. A preliminary account of the structure has been reported.6 Experimental Section Microcrystalline [Cu((CH,),PS)Cl], was readily prepared by (5) P. M. Boorman and K. J . Reimer, Cun. J . Chem., 49,2928 (1971). ( 6 ) J . A. Tiethof, J . K. Stalick, P. W. R. Corfield, and D. W. Meek, J . Chem. Soc., Chem. Commun., 1141 (1972).
