Structural, Magnetic, and Electrochemical Studies on Macrocyclic

Aug 2, 1988 - structural, magnetic and electrochemical properties. The binuclear center dimensions of [Cu,(UPM)(H,O),] [CUI-. (UPM)(H20)2(C104)2](C104...
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Inorg. Chem. 1989, 28, 3707-3713

3707

Contribution from the Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1 B 3x7, and Chemistry Division, National Research Council, Ottawa, Ontario, Canada K1 A OR6

Structural, Magnetic, and Electrochemical Studies on Macrocyclic Dicopper(I1) Complexes with Varying Chelate Ring Size Sanat K. Mandal,'* Laurence K. Thompson,*,la M i c h a e l J. Newlands,la and Eric J. GabetJb Received February 16, 1989 Binuclear macrocyclic copper(I1) complexes involving ligands derived by condensation of 4-methyl-2,6-diacetylphenol with 1.2diaminoethane (MeUEM) and 4-methyl-2,6-diformylphenol with 1,3-diaminopropane(UPM) and 1,4-diaminobutane(UBM), which have chelate rings of varying size (five-, six-, and seven-membered, respectively), have been compared in terms of their structural, magnetic and electrochemical properties. The binuclear center dimensions of [Cu,(UPM)(H,O),] [CUI(UPM)(H20)2(C104)2](C104)2 and [Cu,(UBM)(ClO,),] are very similar, and both compounds exhibit comparable, strong antiferromagnetic exchange (-2J = 850 (2) and 857 (6) cm-I, respectively). [CLI~(M~UEM)(H~O)~](BF,), has a much smaller binuclear center, including a reduced Cu-O-Cu bridge angle, and is less strongly coupled (-2J = 689 (3) cm-I). Chelate ring size also affects values for one-electron reduction, with [CU~(UBM)(CIO,)~] exhibiting the most positive reduction potentials. The crystal and molecular structures of [Cu2(UPM)(H20),][CU~(UPM)(H~O)~(CIO,)~] (ClO,), (I) and [CU~(UBM)(CIO~)~] (11) are reported. I crystallized in the monoclinic system, space group P21/a, with a = 14.7242 ( 5 ) A, b = 12.3816 (3) A, c = 16.5571 (6) A, j3 = 105.681 (3)O, and Z = 4. I1 crystallized in the monoclinic system, space group m 1 / c ,with a = 8.6653 (3) A, b = 16.7173 (13) A, c = 9.9714 (6) A, 0 = 97.273 (4)O, and Z = 8. Two different molecules are found in the unit cell of I, one involving square-pyramidal copper centers and the other six-coordinate copper centers. In I1 two asymmetrically bound, axial, bidentate perchlorates complete the distorted six-coordinate structure at each copper atom.

Introduction Macrocyclic dicopper(I1) complexes of Robson-type ligands have been the focus of a great deal of recent attention,>I7 especially from the standpoint of their electrochemical properties. Sequential one-electron-reduction steps a t negative potentials (V vs SCE) with large potential separations lead to the generation of relatively stable "odd"-electron intermediates that exhibit commonly four-line and less commonly seven-line EPR spectra in solution.4*6g8s11*15 The four-line spectrum indicates the localization of the odd electron at one copper center, while the seven-line spectrum indicates delocalization of the electron over both copper centers ( I = 3/z). It is significant that seven-line spectra have only been obtained for ligands involving unsaturated nitrogen donors derived from 2,ddiformylphenols (Figure 1; R = H, R' = Me, n = 3,4; R = H, R' = tBu, n = 3,46,8911)and that nitrogen saturation and substitution a t the azomethine carbon center leads to four-line ~ p e c t r a . ~ Saturation ,'~ of the azomethine nitrogen donors leads to macrocyclic dicopper(I1) complexes that, in addition to undergoing sequential one-electron-reduction steps, can also undergo sequential one-electron oxidation with the formation of Cu"Cu"' and C U " ' C U ~species.I5 ~~ Odd-electron intermediates have been shown to exhibit four-line solution EPR spectra a t room temperature.15 The proximity of the two copper(I1) centers in these phenoxo-bridged complexes leads to a situation where strong antiferromagnetic exchange has been o b ~ e r v e d , ~ according -~J~*~~ to variable-temperature magnetic studies, with -25 > 580 cm-'. In this report we describe the X-ray structures of the complexes [C~z(UPM)(HzO)zI[Cuz(UPM)(HzO)z(C104)21 (c104)2 (1) and [ C U ~ ( U B M ) ( C ~ O(11) ~ ) ~(Figure ] 1). Both of these compounds have been reported previously, but no structural details have been published HI'). Two different molecules exist in the unit cell in I, one involving square-pyramidal copper(I1) centers with axially bound water and the other involving six-coordinate copper(I1) centers with a trans-axial arrangement of coordinated water and monodentate perchlorate. This contrasts with the complex CU,(UPM)(TCNQ)~( T C N Q = 7,7',8,8'-tetracyanoquinodimethane), which contains a single binuclear cation with square-pyramidal copper(I1) centers involving an apical interaction with a T C N Q nitrogen.I6 The structure of I1 involves two sixcoordinate copper( 11) atoms in an asymmetric trans arrangement having axially bound bidentate perchlorates. Both complexes exhibit very strong antiferromagnetic exchange (-2J = 850 ( 2 ) (I), 857 (6) cm-I (11)), a feature common to fairly planar systems of this sort involving diphenoxo bridges. The complexes [Cuz(I,296.8910*17

*To whom correspondence should be addressed. 'This paper assigned NRCC Contribution No. 30528.

(MeUPM)](C104)z (111) and [CU~(P~UPM)](C~O~)~~~.~H~O (IV) are also found to be strongly coupled (-2J = 835 (5) (111), 806 (9) cm-' (IV)). Electrochemical studies on I1 indicate a more thermodynamically favored one-electron-reduction step compared with that in I, and the one-electron-reduced species exhibits a seven-line EPR involving spectrum. Complex V, [CU~(M~UEM)(H~O)~](BF~)~,~~ a macrocyclic ligand with five-membered chelate rings (Figure 1), has a one-electron-reduction potential comparable to that of I, despite the constraints imposed by the ethylene bridge.

Experimental Section Wysical Measurements. Variable-temperature magnetic susceptibility data were obtained in the temperature range 5-300 K with an Oxford

Instruments superconducting Faraday magnetic susceptibility system with a Sartorius 4432 microbalance. A main solenoid field of 1.5 T and a gradient field of 10 T m-I were employed. HgCo(NCS), was used as calibrant. The electrochemical experiments were performed at room temperature in dimethyl sulfoxide (Me2S0 spectroscopic grade, dried over molecular sieves) and acetonitrile (spectroscopic grade, dried over molecular sieves) under 02-freeconditions with use of a BAS CV27 Voltammograph and a Hewlett-Packard XY recorder. A three-electrode system was used (cyclic voltammetry) in which the working electrode was glassy carbon (GC) and the counter electrode platinum, with a standard calomel (a) Memorial University of Newfoundland. (b) National Research Council. Pilkington, N. H.; Robson, R. Ausr. J. Chem. 1970, 23, 2225. Okawa, H.; Kida, S . Bull. Chem. SOC.Jpn. 1972,45, 1759. Addison, A. W. Inorg. Nucl. Chem. Lett. 1976, 12, 899. Hoskins, B. F.; McLeod, N. J.; Schaap, H. A. Aust. J. Chem. 1976,29, 515. Gagnt, R. R.; Koval, C. A.; Smith, T. J. J . Am. Chem. SOC.1977,99, 8367. Lambert. S. L.: Hendrickson. D. N. Inorp. Chem. 1979. 18. 2683. Gagn6, R.R.; Koval, C. A.; S k t h , T. J.; CiGolino, M. C. J.Am: Chem. SOC.1979, 101, 4571. Gagnt, R. R.; Henling, L. M.; Kistenmacher, T. J. Inorg. Chem. 1980, 19. 1226. Mandal, S . K.; Nag, K. J . Chem. SOC.,Dalton Trans. 1983, 2429. Long, R. S.;Hendrickson, D. N. J. Am. Chem. SOC.1983, 105, 1513. Mandal, S. K.; Nag, K. J . Chem. Soc., Dalton Trans. 1984, 2141. Carlisle, W. D.; Fenton, D. E.;Roberts, P. B.; Casellato, U.; Vigato, P. A,; Graziani, R. Transition Met. Chem. 1986, 11, 292. Mandal, S.K.; Thompson, L. K.; Nag, K.; Charland, J.-P.; Gabe, E. J. Inorg. Chem. 1987, 26, 1391. Mandal, S. K.; Thompson, L. K.; Nag, K.; Charland, J.-P.; Gabe, E . J. Can. J . Chem. 1987,65, 2815. Lacroix, P.; Kahn, 0.; Gleizes, A.; Valade, L.; Cassoux, P. Nouu. J. Chim. 1984, 8, 643. Lacroix, P.; Kahn, 0.; Theobald, F.; Leroy, J.; Wakselman, C. Inorg. Chim. Aero 1988, 142, 129.

0020-1669/89/1328-3707$01.50/00 1989 American Chemical Society

Mandal et al.

3708 Inorganic Chemistry, Vol. 28, No. 19, 1989 R’

h

R‘

Figure 1. Macrocyclic ligands UPM (R = H, R’ = Me, n = 3), UBM (R = H, R’ = Me, n = 4), MeUPM (R = Me, R’ = Me, n = 3), PrUPM (R = Pr”, R’ = Me, n = 3), and MeUEM (R = Me, R’ = Me, n = 2).

(a) Compound I chem formula: C U ~ C ~ ~ H fw~ =~751.41 C ~ ~ N ~ ~ ~ ~ u = 14.7242 (5) 8, space group: E 1 / u b = 12.3816 (3) 8, T=22OC c = 16.5571 (6) 8, A = 1.54056 8, @ = 105.681 (3)O paled = 1.717 g cm-’ V = 2906.17 8,’ p = 4.04 mm-’ z = 4 R = 0.061 R, = 0.049 (b) Compound I1 chem formula: CU2C26H&12N4010 fw = 189.13 u = 8.6653 (3) 8, space group: R 1 / c b = 16.7173 (13) 8, T=22OC h = 0.709 30 8, c = 9.9714 (6) 8, /3 = 97.273 (4)O paled = 1.754 g cm-’ V = 1432.84 8,’ 1 = 1.74 mm-I Z=8 R = 0.060 R, = 0.063

Table 11. Final Atomic Positional Parameters and Equivalent electrode (SCE) as reference. The ferrocenium/ferrocene internal poIsotropic Debye-Waller Temperature Factors (Esd’s) for tential marker has been used to compare redox potentials in Me2S0, and [Cu2(UPM)(H20)21 [Cu2(UPM)(H20)2(C104)21(c104)2 (1) ElI2values are also quoted versus the normal hydrogen electrode (NHE) X Y z B h , AZn (EII2(Fct/Fc) = +0.400 V vs NHE).I8 For coulometry measurements 2.97 (8) 0.47662 (10) 0.38546 (11) 0.46311 (9) Cu(1) a three-electrode system was employed consisting of a platinum-mesh-flag 0.05479 (25) 0.09902 (23) 4.83 (20) Cl(1) 0.3197 (3) working electrode, a platinum-mesh counter electrode, and a SCE ref0.3791 (3) 0.4891 (3) 5.85 (22) Cl(2) 0.2302 (3) erence electrode. The supporting electrolyte was tetraethylammonium 0.4284 (4) 2.8 (4) 0.4700 (5) 0.5390 (5) 0(1) perchlorate (TEAP) or tetrabutylammonium perchlorate (TBAP 0.1 M), 0.0212 (7) 0.0642 (6) 8.6 (6) O(3) 0.2259 (7) and all solutions were 10-’-104 M in complex. The best combination 0.1673 (6) 0.1082 (5) 7.3 (6) O(4) 0.3176 (6) of experimental conditions (working electrode, scan rates, solvent, etc.) 0.0274 (9) 0.0463 (7) 12.8 (9) O(5) 0.3718 (8) was determined by preliminary experiments. 0.0070 (7) 0.1761 (6) 12.0 (9) O(6) 0.3560 (9) EPR experiments were carried out at room temperature by using a 0.4262 (10) 0.4765 (8) 13.3 (10) O(7) 0.3088 (7) Bruker ESP 300 X-band spectrometer. Samples of the air-sensitive 0.4368 (9) 0.5422 (8) 12.7 (10) O(8) 0.1947 (9) mixed-valence species were prepared under nitrogen and loaded into the 0.2781 (8) 0.5219 (7) 10.9 (8) 0(9) 0.2563 (8) EPR tubes with use of syringe techniques. 0.4177 (7) 14.2 (9) 0.1603 (9) 0.3713 (10) O(10) Syntbesis of Complexes. [Cu2(UBM)(CIO4),] (11). 1,4-DiaminoH20(1) 0.6345 (6) 0.3830 (8) 0.4409 (5) 8.7 (7) butane (0.612 g, 6.00 mmol) dissolved in methanol (10 mL) was added 0.3476 (5) 3.4 (5) 0.4235 (6) 0.3366 (7) N(l) to a solution of C ~ ( C 1 0 ~ ) ~ . 6(1.48 H ~ 0g, 4.00 mmol) in methanol (25 0.2435 (6) 0.5166 (5) 2.6 (5) N(2) 0.4863 (6) mL). A solution of 2,6-diformyl-4-methyIphen0I~~ (0.654 g, 4.00 mmol) 0.3557 (6) 2.5 (6) 0.4265 (7) 0.5839 (9) C(l) in hot methanol (50 mL) was then added and the resulting mixture 0.6957 (8) 0.3448 (7) 2.6 (6) C(2) 0.4208 (7) refluxed for 7 h with stirring. When the mixture was cooled to room 0.7355 (11) 0.2657 (9) 3.7 (8) C(3) 0.3732 (9) temperature, a dark khaki green microcrystalline product was obtained, 0.6752 (11) 0.1965 (7) 3.5 (7) C(4) 0.3322 (8) which was collected by filtration and washed several times with cold 0.5673 (11) 0.2075 (7) 3.4 (7) C(5) 0.3412 (8) water. Well-grown crystals suitable for X-ray analysis were obtained by 0.5172 (8) 0.2848 (6) 2.6 (6) C(6) 0.3871 (7) making a boiling saturated aqueous solution of the compound and al0.1161 (11) 5.7 (11) C(7) 0.2829 (15) 0.7282 (17) lowing it to cool slowly to room temperature (yield l .12 g). Anal. Calcd 0.3997 (9) 0.2854 (7) 3.5 (6) 0.3906 (8) C(8) C, 41.28; H, 4.00, N, 7.41. Found: C, for [CU~(C~~H~~N~O~)(CIO,)~]: 0.3276 (10) 6.6 (11) C(9) 0.4225 (14) 0.2211 (10) 41.35; H, 3.94; N, 7.32. The synthesis of this compound has been re0.3839 (14) 8.5 (15) 0.3822 (22) 0.1626 (19) C(10) ported previously.” 0.4726 (10) 4.1 (8) C(l1) 0.4429 (12) 0.1433 (10) The syntheses of the complexes [ C U ~ ( U P M ) ( H ~ O [Cu2)~] 0.2257 (8) 0.5923 (7) 2.9 (6) C(12) 0.5334 (7) (UPM)(H20)2(CIO4)2I(C104)2(I),1o[Cu2(MeUPM)I(C1O4)2(III)?~lo 3.18 (9) 0.03470 (11) 1.09101 (11) 0.06516 (9) [CU~(P~UPM)](C~O~)~.~.~H~O (IV),Io and [ C U ~ ( M ~ U E M ) ( H ~ O ) ~ ] -Cu(2) 0.9342 (5) 0.0565 (4) 2.7 (4) 0.0113 (4) (BF4)2 (V)I3 have been reported already. Anal. Calcd for [ C U ~ ( C ~ ~ - O(2) H20(2) 0.8704 (4) 0.1268 (5) 0.0632 (4) 3.7 (4) (V): C, 40.68; H, 4.46; N, 7.30. Found: C, H30N402)(H20)2](BF4)2 1.0877 (7) 0.1861 (6) 3.9 (5) N(3) 0.0874 (6) 41.11; H, 4.48; N, 7.52. 0.7538 (6) -0.0495 (6) 3.4 (5) N(4) -0.0595 (6) Crystallographic DPta Collection and Refinement of tbe Structures. 2.7 (6) 0.8590 (8) 0.1158 (7) 0.0398 (7) C(21) [C~~(UPM)(H~~)~ICU~(UPM)(HZO)~(~~,)~I(~~~)Z (1). Crystals of 0.7495 (8) 0.0975 (7) 2.9 (6) C(22) 0.0239 (8) I are green. The diffraction intensities of an approximately 0.20 X 0.20 0.6733 (10) 0.1613 (8) 3.8 (7) C(23) 0.0563 (8) X 0.20 mm crystal were collected with graphite-monochromatized Cu Ka 0.6970 (9) 0.2413 (8) 3.6 (7) C(24) 0.1047 (8) radiation by using the 8/28 scan technique with profile analysism to 28, 0.2574 (9) 4.2 (9) 0.1174 (10) 0.8034 (12) C(25) = 99.9’ on a Picker four-circle diffractometer at 295 K. A total of 2999 0.8878 (9) 0.1990 (7) 3.2 (6) C(26) 0.0883 (8) reflections were measured, of which 2996 were unique and 2197 were 0.3067 (11) 7.2 (12) 0.1392 (17) 0.6080 (17) C(27) considered significant with Inet> 2.5c(Inet). Lorentz and polarization 0.2261 (8) 4.7 (8) C(28) 0.1031 (10) 0.9992 (12) factors were applied, but no correction was made for absorption. The 0.2359 (7) 6.8 (10) C(29) 0.1165 (11) 1.1895 (10) cell parameters were obtained by the least-squares refinement of the 1.28990 0.19804 3.69 C(30) 0.08446 setting angles of 68 reflections with 28 = 1OC-12O0 ( ~ ( C U Ka) = C(30)’ 0.15580 1.26945 0.20247 4.47 1.540 56 A). 0.6857 (9) -0.1206 (8) 5.4 (8) C(31) -0.1106 (9) The structure was solved by direct methods with use of M U L T A N ~and ~ 0.0184 (7) 3.4 (7) -0.0277 (7) 0.7018 (9) C(32) refined by full-matrix least-squares methods to final residuals of R = OB,,,

(18) Koepp, H. M.; Wendt, H.; Strehlow, H. 2.Efektrochem. 1960,64,483. (19) Ullman, F.; Brittner, K.Chem. Ber. 1909, 42, 2539. (20) Grant, D. F.; Gabe, E. J. J. Appf. Crystaflogr. 1978, 1 1 , 114. (21) Germain, G.; Main, P.; Woolfson, M. M. Acta Crysraffogr.1W1,A27,

368.

is the mean of the principal axes cf the thermal ellipsoid.

0.061 and R, = 0.049 for the significant data (0.088 and 0.051 for all data) with weights based on counting statistics. Hydrogen atoms were placed in calculated positions but not refined. Crystal data are given in Table I, and final atomic positional parameters and equivalent isotropic

Inorganic Chemistry, Vol. 28, No. 19, 1989 3709

Macrocyclic Dicopper(I1) Complexes Table 111. Final Atomic Positional Parameters and Equivalent Isotropic Debye-Waller Temperature Factors (Esd's) for [C~z(UBM)(C104)zI(11) X Y z B h , A'" 0.027441 (23) 0.39543 (4) 2.367 (13) Cu 0.10151 (4) 0.23830 (8) 3.15 (3) CI -0.19441 (9) -0.10227 (5) 0 0.09174 (23) -0.05545 (12) 0.53067 (20) 2.45 (7) 4.81 (13) -0.07667 (19) 0.2403 (3) O(1) -0.0352 (3) 5.37 (14) -0.10964 (20) 0.3738 (3) O(2) -0.2306 (4) 5.82 (16) -0.17684 (18) 0.1689 (3) O(3) -0.2126 (4) 7.02 (18) -0.04511 (22) 0.1662 (4) O(4) -0.2935 (4) -0.01062 (15) 0.35559 (25) 2.53 (10) N(1) 0.3071 (3) 0.0644 (3) 0.11283 (16) 0.26425 (24) 2.58 (10) N(2) 2.27 (10) -0.12831 (18) 0.5273 (3) C(l) 0.1514 (3) 2.39 (10) 0.1074 (3) -0.19015 (18) 0.6099 (3) C(2) -0.26741 (19) 0.5986 (3) 2.68 (11) C(3) 0.1651 (3) 2.82 (12) -0.28644 (19) 0.5102 (3) C(4) 0.2706 (4) 2.78 (11) -0.22398 (20) 0.4387 (3) C(5) 0.3239 (4) -0.14535 (18) 0.4445 (3) 2.42 (11) C(6) 0.2680 (3) C(7) 0.3248 (6) -0.37136 (25) 0.4968 (5) 4.30 (18) -0.08432 (20) 0.3748 (3) 2.68 (12) C(8) 0.3456 (3) 3.19 (14) 0.03776 (22) 0.2972 (4) C(9) 0.4282 (4) 0.12700 (21) 0.2925 (3) 3.18 (13) C(10) 0.3992 (4) 0.15458 (24) 0.1654 (3) 3.39 (14) C(11) 0.2976 (4) 3.14 (13) 0.11067 (24) 0.1411 (3) C(12) 0.1434 (4) 2.77 (12) 0.17617 (21) 0.2820 (3) C(13) -0.0136 (4)

a

A

H 201A

b

B h is the mean of the principal axes of the thermal ellipsoid.

temperature factors are listed in Table 11. All calculations were performed with the NRCVAX system of and scattering factors were taken from ref 23. Anisotropic thermal parameters (Table SI) and a listing of structure factors are included as supplementary material. [ C U ~ ( U B M ) ( C ~ O(11). ~ ) ~ Crystals ] of I1 are green. The diffraction intensities of an approximately 0.20 X 0.20 X 0.20 mm crystal were collected with graphite-monochromatized Mo Kar radiation by using the 8/28 scan technique with profile analysisa to 20- = 60.0' on a Nonius diffractometer at 295 K. A total of 7023 reflections were measured, of which 4171 were unique and 2902 were considered significant with I,, > 2.5u(Inet). Lorentz and polarization factors were applied, but no correction was made for absorption. The cell parameters were obtained by the least-squares refinement of the setting angles of 21 reflections with 28 = 5 M O 0 (X(Mo Ka) = 0.709 30 A). The structure was solved by direct methods with use of MULTAN~' and refined by full-matrix least-squares methods to final residuals of R = 0.060 and R , = 0.063 for the significant data (0.089 and 0.083 for all data) with weights based on counting statistics. Hydrogen atoms were placed in calculated positions but not refined. Crystal data are given in Table I, and final atomic positional parameters and equivalent isotropic temperature factors are listed in Table 111. All calculations were perand scattering factors formed with the NRCVAX system of were taken from ref 23. Anisotropic thermal parameters (Table SII) and a listing of structure factors are included as supplementary material. Results and Discussion Description of the Structures of [Cu,(UPM) (H 2 0 ) 2 L C ~ 2 -

(UPM)(H,O),(CIO,)21(C104)2(1) and [CUZ(UBM)(C~O~)Z] (n)*

The structure of I is shown in Figure 2, and interatomic distances and angles relevant to the copper coordination spheres are given in Table IV. Two different molecules are found in the unit cell, one involving two pseudooctahedral copper centers with equatorial N202donor sets provided by two azomethine nitrogen centers and two shared, phenoxide oxygen bridging atoms and bound axially by a water molecule and a monodentate perchlorate in a trans axial arrangement (Figure 2a). The axial contacts are fairly long with a copper-water distance of 2.451 (9) A (Cu(l)-H20(l)) and a copper-perchlorate distance of 2.589 (10) 8, (Cu( 1)-O(7)). In-plane distances to the phenoxide bridge (1.981 ( 6 ) , 1.989 (6) A) are somewhat longer than those reported for related ethylenediamine- and propylenediamine-bridged complexes with weakly

(22) Gab, E. J.; Lee,F. L.;LePage, Y. In Crystallographic Computing II& Sheldrick, G., Kruger, C., Goddard, R., Eds.; Clarendon Press: Oxford, England, 1985; p 167. (23) International Tables for X-ray Crystallography;Kynoch Press: Birmingham, England, 1974; Vol. IV, Table 2.2B, p 99.

i/C3lA

-w w 3 0 A

Figure 2. Structural representation for (a) [ C U ~ ( U P M ) ( H ~ O ) ~ ( C ~ O ~ ) ~ ] of I and (b) the cation [ C U ~ ( U P M ) ( H ~ O )of~ ]I ~with + hydrogen atoms omitted (40% probability thermal ellipsoids). Table IV. Interatomic Distances Copper Coordination Spheres in

(A) and Angles (deg) Relevant to the

[cud UPM)(H20)21[ ~ ~ z ( ~ ~ ~ ) ( ~(clod2 z ~ ) (1) 2 Cu(l)-Cu(l)A 3.091 (3) Cu(l)-H20(1) Cu(1)-N(1) CU(l)-O(l) 1.981 (6) Cu(l)-O(l)A 1.989 (6) Cu(l)-N(2) O(l)-Cu(l)A Cu( 1)-O(7) 2.589 (10) O(l)A-C~(1)-0(7) O(I)A-Cu(l)-H20(1) O(l)A-Cu(l)-N(l) O(l)A-Cu(l)-N(2) 0(7)CU(l)-H20(1) 0(7)-Cu(l)-N( 1) O(l)-Cu(l)-O(l)A O(X)-CU( 1)-0(7)

89.1 (3) 89.0 (3) 169.9 (3) 92.9 (3) 168.9 (4) 90.3 (4) 77.7 (3) 82.2 (3)

C U ( ~ ) - C U ( ~ ) A 3.096 (3) CW-O(2) 1.970 (6) Cu(2)-0(2)A 1.970 (6) C~(2)-H20(2) 2.451 (6)

( ~ ~ ~ 4 ) ~ 1 2.451 (9) 1.956 (8) 1.957 (8) 1.989 (6)

O(l)-Ch(l)-H~O(l) 86.7 (3) O(l)-CU(l)-N(l) 92.2 (3) 0(l)-C~(l)-N(2) 170.3 (3) 0(7)-Cu(l)-N(2) 95.2 (4) HZO(l)-Cu(l)-N(l) 89.7 (3) H20(1)-C~(l)-N(2) 95.8 (3) N(l)-Cu(l)-N(2) 97.2 (4) Cu(1)-O(l)-Cu(l)A 102.3 (3) Cu(2)-N(3) Cu(2)-N(4) 0(2)-C~(2)A

0(2)-C~(2)-N(4) 168.1 (3) 0(2)-Cu(2)-H20(2) 0(2)A-C~(2)-H,0(2) 87.10 (24) 0(2)-C~(2)-N(3) 0(2)A-C~(2)-N(3) 169.3 (3) HzO(2)