Inorg. Chem. 1984, 23, 4242-4248
4242
will be dominated by the 6-membered ring pair awaits confirmation. remain Some assignments in the literature that There modification* The absolute 'Onfiguration Of the cO(en)(~yclam)~+ enantiomer presented by Lai and h o n 4 (Figure 2 ) should be (SSSS), and the chirality defined by the 5membered chelate rings in isomer I (Figure 3 of ref 6) should be A. A c b w J d p n t *We thank the New Universities Grants Committee and the Department of Scientific and Industrial Research for providing funds to purchase instruments used in this research. We also thank a reviewer for drawing our attention to a method for the complete isomeric enu-
meration of trans-octahedral cyclam complexes.28 Registry No. [Cr(ox)(cyclam)]C104,931 10-52-2; cis-[CrCI2(cyclam)]C10,, 27435-97-8; (-)-[Cr(ox)(cyc]am)]C104, 93219-75-1; (-)-~is-[CrC1~(cyclam)]ClO~, 93219-77-3; (+)-cis-CrCl(cyclam)OH^)^+, 93220-77-0; (+)-~is-Cr(cyclam)(OH~)~~+, 93219-78-4; (-)-cis-Cr(OH),(cyclam)+, 931 10-53-3. Supplementary Material Available: Tables of bond lengths, bond angles, anisotropic temperature factors, coordinates of hydrogen atoms, and calculated and observed structure factors (8 pages). Ordering information is given on any current masthead page,
(28) Tapscott, R. E.; Mancovich, D. Inorg. Chem. 1978, 17, 2050.
Contribution from the Chemistry Department, University of Canterbury, Christchurch, New Zealand
X-ray Crystal and Molecular Structures of Related Octahedral Magnesium Tetraphenylporphyrin Complexes V. McKEE, C H I N C H O O N ONG, and G. A. RODLEY*
Received January 15, 1984 The crystal and molecular structures are reported for the magnesium tetraphenylporphyrin complexes, MgTPP( 1methylimida~ole)~ M g T P P ( C p i ~ l i n e ) ~and , MgTPP(piperidine),. MgTPP( 1-methylimidazole), crystallizes in the tetragonal space group P4,/n with 4 molecules per unit cell of dimensions a = 20.764 (5) A, c = 9.659 (3) 8,. MgTPP(4-pi~oline)~ and MgTPP(~iperidine)~ are isostructural. These two compounds crystallize in the triclinic space group Pi with 1 molecule in unit cells ofdimensions a = 10.146 (2), 9.944 (3) 8,, b = 11.210 (2), 11.436 (3) A, c = 11.643 (3), 11.914 (3) A, a = 65.63 (2), 101.78 (2)O, p = 76.32, 104.59 (2)O, and y = 67.42 ( l ) , 115.60 (2)O, respectively. As observed for related complexes the binding in the axial, octahedral positions is weak. The Mg-N axial bond distances are long, varying from 2.297 (8) 8, (I-methylimidazole) to 2.386 (2) and 2.419 (3) 8, (4-picoline and piperidine, respectively). Corresponding values for isostructural low-spin Fe(I1) 1-methylimidazole and piperidine complexes are significantly shorter, indicating that an absence of tzg electrons for Mg(I1) limits the binding of axial ligands to porphyrin systems to a significant extent. The stronger binding of I-methylimidazole, compared with piperidine, for both Mg(I1) and Fe(I1) complexes indicates that an electronic effect as well as a smaller steric interaction favors the axial coordination of this ligand.
Introduction The crystal and molecular structures of metalloporphyrins have been of considerable interest because of their relevance to the structure and function of biological compounds.' The majority of these metalloporphyrin structures consist of elements in the first-row transition series, particularly iron., However, the structures of magnesium porphyrins are also of interest because of their relationship to chlorophyll, as highlighted in a recent report.3 Most X-ray structural studies of magnesium macrocyclic tetrapyrrole complexes are those of five-coordinated entities. In these cases the magnesium atom is displaced out of the mean plane of the four chelating nitrogen atoms toward the axial ligands, by values ranging from 0.21 to 0.496 A.3-9 ( I ) Scheidt, W. R.; Reed, C. A. Chem. Rev. 1981, 81, 543, (2) Scheidt, W. R. Acc. Chem. Res. 1977, 10, 339. (3) Barkigia, K. M.; Spaulding, L. D.; Fajer, J. Inorg. Chem. 1983, 22, 349. (4) Fischer, M. S.; Templeton, D. H.; Zalkin, A,; Calvin, M. J. Am. Chem. SOC.1971, 93, 2622. (5) Timkovich, R.; Tulinsky, A. J. Am. Chem. SOC.1969, 91, 4430. (6) Chow, H. C.; Serlin, R.; Strouse, C. E. J. Am. Chem. Soc. 1975, 97, 7230. (7) Serlin, R.; Chow, H. C.; Strouse, C. E. J. Am. Chem. Soc. 1975, 97, 7237. (8) Kratky, C.; Dunitz, J. D. Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 1977, 833, 545.
0020-1669/84/1323-4242$01.50/0
Equilibrium studies of Mg porphyrins with nitrogenous bases also indicate that five-coordination is the preferred coordination state of Mg. However, under suitable conditions, six-coordination can be realized'"-'3 as shown in particular by X-ray structural results. Although the first attempt to determine the crystal structure of a six-coordinated complex, (Mg etioporphyrin)(py), (py = pyridine), was limited by a high degree of disorder, it did reveal the existence of long Mg-N axial ligand bonds.l4-I6 More recently, a complete structure determination of six-coordinated MgOEP(py), (OEP = octaethylporphyrin) confirmed this resu1t.l' In this paper, we report details of the crystal and molecular structures of three related six-coordinated MgTPP (TPP = tetraphenylporphyrin) complexes, MgTPP( 1-MeIm), (9) Kratky, C.; Isenring, H. P.; Dunitz, J. D. Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 1977, 833, 547. (10) Rodley, G. A.; Ong,C. C. Inorg. Chim. Acta 1983, 78, 171. (11) Miller, J. R.; Dorough, G. D. J. Am. Chem. Sac. 1952, 74, 3977. (12) Storm, C. B.; Corwin, A. H.; Arellano, R. A,; Martz, M.; Weintraub, R. J . Am. Chem. SOC.1966, 88, 2525. (13) Kadish, K. M.; Shiue, L. R. Inorg. Chem. 1982, 21, 3623. (14) Hoard, J. L. Science (Washington, D.C.)1971, No. 174, 1295. (1 5 ) Hoard, J. L. In "Porphyrins and Metalloporphyrins"; Smith, K. M., Ed.; Elsevier: Amsterdam, 1975; p 317. (16) Collins, D. M.; Hoard, J. L. J. Am. Chem. SOC.1970, 92, 3761. (17) Bonnett, R.; Hursthouse, M. B.; Malik, K. M. A,; Mateen, B. J. Chem. Soc., Perkin Trans. 2 1977, 2072.
0 1984 American Chemical Society
Inorganic Chemistry, Vol. 23, No. 25, 1984 4243
Magnesium Tetraphenylporphyrin Complexes
Table 11. Atom Coordinates (X l o 4 ) and Temperature Factors (A') of MgTPP(1-MeIm),
Table I. Crystal Data
empirical formula mol wt cryst syst space group cell dimens a, A b, .A c, A
MgT PP(1-MeIm),
MgTPP(4-pic)'
MgTPP(pip),
C,,H,,N,Mg 801.3 tetragonal P4,ln
C,,H,,N,Mg 823.3 tficlinic P1
C,,H,,N,Mg 806.9 triclinic
PI
20.764 (4)
4164.3 1.28 1.28 4 1679.6 0.85 0.22 X 0.2 X 0.2 0.31 Mo Kcu 3-45 2741
10.146 (2) 11.210 (2) 11.643 (3) 65.63 (2) 76.32 (2) 67.42 (1) 1108.9 1.25 1.23 1 431.91 0.81 0.43 X 0.19 X 0.21 0.25 Mo Kcu 3-50 3927
9.944 (3) 11.463 (3) 11.914 (3) 101.78 (2) 104.59 (2) 115.60 (2) 1103.7 1.23 1.21 1 425.91 0.79 0.56 X 0.75 0.28 0.22 Mo Ka 3-50 3907
1132
2059
2144
0.074 0.057 -0.00
0.0449 0.045 -0,000 109
0.0591 0.0579 -0.000 262
9.659 (3)
deg P , deg -r, deg 01,
v, A3
D m e a d , g cm" Dcalcd, g cm-3 Z
F(000) p, cm-' cryst dimens, mm mosaicity radiation 20 range total no. of indep reflcns no. of reflcns with 1, > 30(Z0)
R Rw g
atom
X
(1-MeIm = 1-methylimidazole), MgTPP(Cpic), (pic = picoline), and MgTPP(pip), (pip = piperidine). Two of these structures, MgTPP( 1-MeIm), and MgTPP (pip),, are isomorphorous with those reported for the low-spin iron(I1) a n a l o g ~ e s , ' ~while J ~ MgTPP(4-pic), and MgTPP(pip), are isostructural with each other. From these results a number of useful comparisons can be made, in particular the bonding characteristics of a transition-metal ion (Fe2+)with those of a non-transition-metal one (Mg2'). In addition, the effect of the aromatic character of an axial ligand can be assessed by comparing the structure of the 1-methylimidazole and 4-picoline complexes with that of the piperidine complex. Experimental Section (TPP)H2 was prepared by the condensation of pyrrole and benzaldehydem and purified by a procedure adapted from Barnett et al.,' Mg(I1) was inserted into (TPP)H2 by using the dimethylformamide Shiny, red-purple hexagonal-shaped crystals of method.,, MgTPP( 1-MeIm), were obtained by heating the MgTPP complex in pure 1-methylimidazole and then crystallizing in an acetone-lmethylimidazole solution. The crystals were assigned to the tetragonal system after examination by precession photography, using Mo K a radiation. A similar technique was used to obtain MgTPP(pip), and MgTPP(rl-pic),. Long needlelike crystals were obtained from a solution of chloroform and the nitrogenous ligand. The crystals chosen for data collection were mounted on a computer-controlled Nicolet R3m diffractometer. The cell constants and orientation matrices were determined from a least-squares fit of at least 20 reflections. Important crystal data are summarized in Table I. (18) Radonovich, L. J.; Bloom, A.; Hoard, J. L. J. Am. Chem. SOC.1972, 94, 2073. (19) Steffen, W. L.; Chun, H. K.; Hoard, J. L.; Reed, C. A. 'Abstracts of
Papers", 175th National Meeting of the American Chemical Society, Anaheim, CA, March 1974; American Chemical Society: Washington, DC, 1978; INOR 15. Hoard, J. L., private communication. (20) Adler, A. D. J . Org. Chem. 1967, 32, 476. (21) Barnett, G. H.; Hudson, M. F.; Smith, K. M. J . Chem. SOC.,Perkin
Trans. I , 1975, 9, 1401. (22) Adler, A. D.; Longo, F. R.; Kampas, F.; Kim, J. J. Inorg. Nucl. Chem. 1970, 32, 2443.
X
Y
Z
5000 4609 (3) 4100 (3) 5246 (4) 5642 (5) 4958 (4) 4528 (4) 3937 (4) 3989 (3) 3485 (4) 3545 (4) 3043 (4) 3281 (4) 6043 (4) 5615 (4) 5912 (4) 5740 (4) 6038 (4) 6510 (4) 6690 (4) 6379 (3) 5630 (5) 5273 (5) 5036 (5) 6024 (6) 5300 (13) 2820 (4) 2532 (4) 1918 (4) 1600 (4) 1861 (4) 2481 (4)
0 908 (3) -332 (3) 299 (4) 396 (5) 1449 (4) 2001 (4) 1770 (4) 1085 (3) 674 (4) 20 (4) -392 (4) -990 (4) 951 (4) 1478 (4) 2128 (4) 2494 (4) 3086 (4) 3297 (4) 2954 (4) 2364 (4) 22 (5) 886 (5) 840 (5) 266 (6) 1202 (12) 951 (3) 1116 (4) 1400 (4) 1497 (4) 1317 (4) 1046 (4)
0 359 (7) -603 (6) -2228 (8) -4333 (9) 628 (8) 576 (8) 263 (8) 114 (9) -308 (8) -690 (8) -1 178 (7) -1383 (7) 982 (8) 957 (8) 1235 (8) 2374 (8) 2635 (10) 1763 (9) 618 (9) 347 (9) -3129 (11) -4180 (1 1) -2911 (11) -5507 (13) -5306 (28) -298 (8) 951 (9) 970 (10) -239 (10) -1455 (9) -1498 (9)
1 0 3 ~ 31 (1)* 34 (3)* 28 (3)* 47 (3)* 79 (5)* 33 (2) 38 (2) 39 (2) 25 (2) 32 (2) 29 (2) 33 (2) 31 (2) 30 (2) 28 (2) 30 (2) 37 (2) 5 0 (3) 49 (3) 56 (3) 41 (2) 67 (5)* 68 (5)* 63 (5)* 60 (5) 50 (10) 29 (2) 56 (3) 67 (3) 59 (3) 56 (3) 45 (3)
Asterisks denote equivalent isotropic Udefined as onethird of the trace of the orthogonalized Uij tensor. Data were collected at room temperature with use of graphitemonochromated Mo K a radiation and the 8-28 scan technique (3O < 28 < 45' (MgTPP(l-MeIm),), SOo (MgTPP(4-pic),), 50' (MgTPP(pip),)). Crystal stabilities were monitored by recording three standard reflections every 100 reflections, and no significant variations were observed. Intensities were corrected for Lorentz-polarization effects, and empirical absorption corrections were applied based on $-scan data. Only those reflections for which I, 3 3u(10) were used in the subsequent structural analyses. The structure of MgTPP(1-MeIm), was solved by direct methods, using the program SOLV, which revealed the positions of all the non-hydrogen atoms. For both MgTPP(Cpic), and MgTPP(pip),, crystal symmetry defined the position of the Mg atom (0, 0,O in each case) and the remaining non-hydrogen atoms were located from difference Fourier maps. The structures were refined by blockedcascade least-squares refinement, and hydrogen atoms were included at calculated positions (C-H = 0.96 A) with thermal parameters equal to 1.2Uof their camer atoms. All the programs used for data reduction and structure solution are included in the SHELXTL (version 3.0) package.23 M g scattering factors were obtained from Cromer and and the anomalous dispersion corrections from Cromer and Liberma~,~ MgTPP( 1-MeIm), was refined to R = 0.074 and R, = 0.057 with all atoms isotropic except the Mg, the coordinated nitrogen atoms, and the 1-MeIm group. A final difference map showed no features greater than f0.3 e A-3. The 1-MeIm group shows twofold disorder about the Mg-N(3) axis; thus, the 1-Me group was found to have site occupancy of 0.68 (C(44)) and 0.32 (C(44') in the two related orientations. MgTPP(4-pic), was refined with all the non-hydrogen atoms anisotropic and converged with R = 0.0499 and R, = 0.045, and the final difference map showed no features greater than f0.26 e A-3. (23) Sheldrick, G. M. 'SHELXTL User Manual", Revision 3; Nicolet XRD Corp.: Cupertino, CA, 198 1. (24) Cromer, D. T.; Mann, J. B. Acta Crystallogr., Sect. A: Cryst. Phys., Diffr., Theor. Gen. Crystallogr. 1968, A24: 321. (25) Cromer, D. T.; Liberman, D. J. Chem. Phys. 1970, 53, 1891.
McKee, Ong, and Rodley
4244 Inorganic Chemistry, Vol. 23, No. 25, 1984 Table 111. Atom Coordinates (X l o 4 ) and Temperature Factors ( A 2 ) of MgTPP(4-pic), atom Mg N(l) N(2) N(5) C(1) C(2) C(3) C(4) C(5 C(6) C(7) C(8) C(9) C(10) C(21) C(22) C(23) C(24) C(25) C(26) C(31) C(32) C(33) C(34) C(35) C(36) C(51) C(52) C(53) C(54) C(55) C(56)
Y 0 0 1253 (3) 1026 (3) 119 (2) -1175 (3) -1633 (3) 2233 (3) -2329 (3) -1413 (3) -2763 (4) -2306 (3) 1935 (3) 2465 (3) 1673 (3) 976 (3) 1588 (3) -85 (3) 880 (3) -1084 (3) 893 (3) -2226 (3) 166 (3) -2989 (3) -319 (3) -2342 (3) -2860 (3) -1062 (3) -4067 (3) -1556 (3) -3859 (4) -2576 (3) -4945 (4) -3111 (4) -6259 (4) -2595 (4) -6507 (4) -1561 (4) -5417 (3) -1044 (4) 2410 (3) -250 (3) 1803 (4) 352 (4) 2562 (4) 117 (4) 3925 (4) -697 (4) 4546 (4) -1287 (4) 3790 (3) -1062 (4) -3038 (4) 2575 (4) 3910 (4) -3969 (4) 4997 (4) -3473 (4) 4649 (4) -2.045 (5) 3293 (4) -1181 (4) 6475 (4) -4444 (5) X
2
0 116 (2) 1686 (2) -1l" (2) 760 (3) 416 (3) 631 (3) 973 (3) 1999 (3) 2324 (3) 3343 (3) 3305 (3) 2262 (3) 1850 (3) 2663 (3) 3852 (3) 4570 (4) 4133 (4) 2986 (4) 2243 (3) 2802 (3) 3937 (3) 4699 (3) 4323 (3) 3192 (4) 2435 (3) -669 (4) -1065 (4) -1830 (3) -2181 (4) -1765 (4) -2246 (4)
1 0 3 ~ 46 (1)* 44 (I)* 43 (I)* 55 (2)* 44 (2)* 53 (2)* 5 3 (2)* 44 (2)* 43 (2)* 41 (2)* 47 (2)* 49 (2)* 41 (2)* 43 (2)* 4.5 (2)* 56 (2)* 77 (2)* 89 (3)* 85 (3)* 66 (2)* 43 (2)* 59 (2)* 67 (2)* 6 2 (2)* 70 (2)* 64 (2)* 69 (2)* 78 (2)* 66 (2)* 85 (2)* 79 (2)* 103 (3)*
a Asterisks denote equivalent isotropic U defined as one-third of the trace of the orthogonalized Uii tensor.
Table IV. Atom Coordinates (X l o 4 )and Temperature Factors ( A 2 ) of MgTPP(pip), atom X Y Z 103p 49 (1)* 0 0 0 Mg 42 (2)* 159 (3) -1661 (2) -1044 (3) N(1) N(2) 2251 (3) 1010 (3) -88 (2) 42 (2)* 1126 (3) 58 (2)* 426 (4) 2226 (3) N(5 1 2226 (3) 43 (1) 2646 (4) 249 (3) C(1) 51 (1) 287 (4) -3220 (3) -2824 (4) C(2) 48 (1) 999 (4) -3238 (3) -1356 (4) c(3) 42 (1) 929 (3) -2263 (3) -225 (4) ~(4) 42 (1) 1464 (4) 1596 (3) -1942 (3) c(5) -927 (3) 40 (1) 2606 (4) 1645 (3) C(6) -573 (3) 48 (1) 4337 (4) 2410 (4) ~(7) 472(3) 48 (1) 5003 (4) 2240 (3) C(8) 783 (3) 41 (1) 3696 (4) 1371 (3) ~(9) 1855 (3) 40 (1) 3897 (4) 1009 (3) C(10) 2695 (3) 43 (2)* 5582 (4) 1501 (4) c(21) 2330 (4) 57 (2)* 289 (4) 6503 (4) C(22) 3124 (4) 66 (3)* ~ ( 2 3 ) 8075 ( 5 ) 1490 (4) 4257 (4) 67 (3)* 2523 (4) 8762 (5) C(24) 4625 (4) 67 (3)* 7857 (5) 3029 (4) C(25) 3865 (3) 56 (2)* 6278 (4) 2507 (4) c(26) 45 (2)* 2102 (4) 2380 (4) -2737 (3) C(3I) 59 (2)* 2077 (5) 1727 (4) -3855 (3) C(32) 67 (3)* 2658 (5) 2467 (4) -4582 (4) C(33) 63 (2)* 3248 (4) 3856 (4) -4212 (4) C(34) 78 (3)* 3284 (5) 4522 (4) -3101 (4) C(35) 69 (3)* 2722 ( 5 ) 3801 (4) -2370 (4) C(36) 490 (4) 74 (3)* -613 (5) 2688 (4) C(51) 1297 (4) 77 (3)* -427 (5) 4004 (4) C(52) 1848 (4) 86 (3)* 1290 (6) 5168 (5) C(53) 2561 (5) 102 (3)* 2353 (6) 4714 (5) C(54) 1737 ( 5 ) 88 (3)* 2108 (5) 3378 (4) c(55) a Asterisk denote equivalent isotropic Udefined as one-third of the trace of the orthogonalized Uij tensor.
For MgTPP(pip), the Mg, coordinated nitrogen a t o m , phenyl groups, and axial ligand were refined anisotropically to give R = 0.0591 and
Table V. Selected Bond Lengths (A) of MgTPP(I-MeIm), Mg-N(l) Mg-N(2) Mg-N(3) N(l)-C(l) N(l)-C(4) N(2)-N(6) N(2)-C(9a) N(3)-C(43) N(3)-C(41) N(4)-C(41) N(4)-C(42) N(4)-C(44) C(l)-C(2)
2.082 (6) 2.074 (6) 2.297 (8) 1.361 (10) 1.360 (9) 1.368 (10) 1.370 (10) 1.373 (14) 1.314 (13) 1.399 (14) 1.282 (15) 1.410 (16) 1.454 ( 1 1 )
C(2)-C(3) C(3)-C(4) C(4)-c(5) W)-C(6) C(5)-C(50) C(6)-C(7) C(7)-C(8) C(8)-C(9a) C(9a)-C(lOa) C(l0)-C(11) C(42)-C(43) C(42)-C(44')
1.352 1.433 (11) 1.496 (10) 1.412 (11) 1.496 (10) 1.429 (11) 1.352 (10) 1.460 (10) 1.409 (11) 1.403 (10) 1.324 (15) 1.272 (28)
Table VI. Selected Angles (de& of MgTPP(1-Meh" N(l )-Mg-N(2) 89.8 (2) N(l )-Mg-N(3) 89.9 (3) N(2)-Mg-N (3) 91.5 (3) Mg-N(I )-C(1 ) 124.9 (5) 125.8 (5) Mg-N(1 )-C(4) 126.8 (5) Mg-N(2)-C(6) 125.6 (5) Mg-N(Z)-C(ga) 108.5 (6) N(l)-C(l)-C(2) 108.8 (6) N(l)-C(4)4(3) N(2)-C(6)-C(5) C(5)-C(6)-C(7) C(8)-C(9a)-C(lOa) Mg-N(3)-C(41) Mg-N(3)-C(43) N(3)-C(41W(4) N(3)-C(43)-C(42) N(4)-C(4i)-C(43) N(4)-C(42)-C(44') C(41 )-N(4)-C(42) C(41)-N(3)4(43) C(41)-N(4)-C(44) C(42>.N(4)-C(44) C(43)C(42)4(44')
109.4 (7) 105.1 (7) 108.2 (6) 107.6 (6) 124.8 (7) 125.0 (7) 126.7 (7) 124.6 (7) 129.6 (7) 126.9 (7) 108.5 (9) 112.8 (9) 105.7 (10) 106.5 (15) 109.6 (9) 103.4 (8) 124.8 (10) 125.6 (10) 147.8 (16)
Table VII. Selected Bond Lengths (A) of MgTPP(4-pic), Mg-N(I) Mg-N(2) Mg-NG) N(l)-C(la) N(l)-C(4) N(z)-c(~) ~(2)-~(9) N(5)-C(51) N(5)-C(55) C(la)-C(Za) C(2a)-C(3) C(3)-C(4) C(4)-C(5)
2.072 (3) 2.069 (2) 2.386 (2) 1.376 (4) 1.380 ( 5 ) 1.380 (5) 1.375 (4) 1.330 (5) 1.329 (5) 1.452 (6) 1.342 (5) 1.444 (6) 1.404 (4)
C(5)-C(6) C(5)-C(31) C(6)-C(7) W)-C(8) C(8)-C(9) C(9)-C(10) C(lO)-C(l) C(lO)-C(21) C(51)-C(52) C(52)-C(53) C(53)-C(54) C(53)-C(56) C(54)-C(55)
1.409 (5) 1.508 (6) 1.450 (4) 1.340 (6) 1.448 (5) 1.408 (6) 1.408 (5) 1.498 (4) 1.377 (5) 1.377 (6) 1.355 (6) 1.503 (5) 1.373 (5)
Table VIII. Selected Angles (deg) of MgTPPWpic), N(l )-Mg-N(2) 90.9 (1) N(l )-Mg-N(5) 86.3 86.6 (1) N(2)-Mg-N(5) Mg-N(l)-C(la) 126.9 (3) Mg-N( 11-C(41 125.1 (2) 125.1 (2) Mg-N(2)-C(6 1 127.4 (3) Mg-N (2)-C (9) N(l)-C(la)-C(2a) 108.9 (3) N(l)-C(4)-C(3) 109.1 (3) 109.0 (3) N(2)-C(6)-C(7) N(2)-C(9)-C(8) 109.4 (3) N(l)-C(la)-C(lOa) 125.5 (2) N(l)-C(4)-C(5) 125.3 (4) 124.8 (3) N(2)-C(9)-C(10) N(2)-C(6)-C(5) 125.5 (3) C(2a)-C(3)-C(4) 107.6 (4) 107.5 (3) C(la)-C(2a)-C(3) 107.6 (4) C(6)-C(7)-C(8) 107.3 (3) C(7)-C(8)-C(9) 127.7 (2) C(4)-C(S)-C(6) C(9)-C(1 O)-C(l) 126.2 (3)
C(la)-N(l)-C(4)
107.0 (3)
125.8 106.6 (3) C(2a)-C(la)C(lOa) C(6)-N(2)-C(9) 125.7 (4) C(3)4(4)4(5) 125.8 (3) C(5)-C(6)-C(7) C(8)-C(9)C(10) 125.8 (3) C(l)-C(IO)-C(21) 116.6 (4) C(9)-C(1O)-c(21) 117.1 (3) C(4)-C(5)-C(31) 117.2 (3) C(6)-C(5)-C(31) 115.6 (3) 122.7 (2) Mg-N(5)-C(51) Mg-N(5)-C(55) 121.7 (2) N(5)-C(51)-C(52) 123.7 (4) N(5)-C(55)-C(54) 124.7 (4) C(5 1)-N(5)-C(55) 114.6 (3) C(5 1)-C(52)-C(53) 120.8 (4) C(52)C(53)4(56) 122.0 (4)
R, = 0.0579 with no features greater than f0.24 e A-' in the final difference map. In all three cases the function minimized was Cw(lF,,l- lFC1)' with w = [cZ(Fo) gF:]-'. Atomic coordinates and associated thermal
+
Inorganic Chemistry, Vol. 23, No. 25, 1984 4245
Magnesium Tetraphenylporphyrin Complexes
Figure 1. Computer-drawn structure of MgTPP( l-MeIm)* showing the numbering scheme (30% probability ellipsoids). Table IX. Selected Bond Lengths (A) of MgTPP(pip), Mg-N(l) Mg-N (2 1 Mg-NG 1 N(l)-C(la) N(l)-C(4) N(2)-C(6) N(2)-C(9) N(5)-C(51) N(S)-C(55) C(la)-C(2) C(2)-C(3) C(3)-C(4) C(4)-C(5)
2.074 (3) 2.071 (3) 2.419 (4) 1.378 (5) 1.374 (5) 1.379 (5) 1.369 (4) 1.470 (7) 1.467 (4) 1.447 (6) 1.338 (5) 1.441 (6) 1.414 (5)
C(5)-C(6) C(5)-C(31) C(6)-C(7) C(7)
