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Structures and Magnetostructural Correlation of Two Desolvated Polymorphs of Ferrimagnetic meso-Tetrakis(4-chlorophenyl)porphinatomanganese(III) Tetracyanoethenide, [MnTClPP]+[TCNE]•- † Jae-Hyuk Her,‡,§ Peter W. Stephens,‡ Joshua D. Bagnato,⊥ and Joel S. Miller* Department of Chemistry, 315 South 1400 East, room 2124, UniVersity of Utah, Salt Lake City, Utah 84112-0850, and Department of Physics & Astronomy, Stony Brook UniVersity, Stony Brook, New York 11794-3800 ReceiVed: June 3, 2010; ReVised Manuscript ReceiVed: August 16, 2010

The structures of two polymorphs of [MnTClPP][TCNE] have been determined by Rietveld refinement of the X-ray powder diffraction method. Samples were prepared by thermolysis of the toluene and CH2Cl2 solvates, [MnTClPP][TCNE] · 2Sol (Sol ) PhMe, CH2Cl2). The desolvated structures are similar to their solvates, consisting of alternating stacks of the molecular donor and acceptor. Among the four structures, the largest changes are observed for the dihedral angle between the mean Mn(N4)TPP and [TCNE]•- planes, and the Mn-(N-C)TCNE angle. A magnetostructural correlation between the intrachain coupling and both the dihedral angle between the mean Mn(N4)TPP and [TCNE]•- planes and Mn-(N-C)TCNE angles is observed. This is in accord with the intrachain coupling arising from the overlap of MnIII dz2-like singly occupied molecular orbital (SOMO) and the z component of the [TCNE]•- π* (πz*) SOMO, which increases with decreasing dihedral angle between the mean Mn(N4)TPP and [TCNE]•- planes and Mn-(N-C)TCNE angle. Introduction [MnIII(porphyrin)]+[TCNE]•- (TCNE ) tetracyanoethylene) organic-based ferrimagnets1,2 are a large, well-studied family, as many members have been both structurally and magnetically characterized. In all cases, the antiferromagnetic coupling and structural motifs possess parallel 1-D chains of alternating S ) 2 [MnIIITPP]+ [TPP ) meso-tetraphenylporphyrinato] cations and bridging S ) 1/2 µ-[TCNE]•- anions. Members differ in their solvate (Sol) of the parent [MnTPP][TCNE] (e.g. [MnTPP][TCNE] · xSol) or the substitution in the phenyl groups of the [MnTPP]+ (1, R ) H). Typically, substitution of hydrogen at the 4-position has been reported, although other substitutions, including multiple substitutions, have been achieved. All magnetically order as ferrimagnets (Tcs e 28 K),3 exhibit spin glass behavior, and have coercive fields as great as 27 kOe at 2 K.4 The dominant spin coupling for members of the [MnIII(porphyrin)]+[TCNE]•- family of ferrimagnets is the intrachain antiferromagnetic coupling (Jintra), as evidenced by the fit of temperature dependence of magnetic susceptibility, χ(T), as χ-1(T), to the Curie-Weiss expression, χ ∝ (T - θ)-1 where θ is the T at which the extrapolated linear fit intercepts the abscissa, and θ > 0 reflects ferromagnetic coupling, whereas θ < 0 reflects antiferromagnetic coupling. Although the latter is sometimes observed at higher temperatures, the former, denoted as θ′, is observed at reduced temperature and is indicative of short-range, ferromagnetic interactions. The higher the value of θ′ suggests stronger interchain coupling, Jintra.5 †

Part of the “Mark A. Ratner Festschrift”. * Corresponding author. Phone: (J.S.M.) +1 801 585 5455, (P.W.S.) 1 631 632. Fax: (P.W.S.) +1 801 581 8433, (P.W.S.) 1 631 632 8176. E-mail: (J.S.M.) [email protected], (P.W.S.) [email protected]. ‡ Stony Brook University. ⊥ University of Utah. § Current address: GE Global Research Center, Niskayuna, NY.

Another approach to obtain Jintra is from a fit of the χT(T) data to the Seiden model6 for isolated chains (Jinter ) 0) composed of alternating quantum S ) 1/2 and classical S ) 2 spins, and cannot account for the interchain (2- and 3-D) interactions. At higher temperatures, the χT(T) data for the [Mn(porphyrin)][TCNE] family can be fit to the Seiden expression, indicating that Jintra is sufficient (i.e., Jinter ) 0) to model the data. In contrast, at low temperature, χT(T) deviates from the fit to the Seiden expression, as growing magnetic correlations along the chains amplify the effect of a weak Jinter. An inverse linear correlation between θ′ and (a) the dihedral angle between the [Mn(porphyrin)]+ and the [TCNE]•- mean planes, and (b) the Mn-(N-C)TCNE angle has been previously reported for a series of substituted [MnTPP][TCNE] · 2PhMe.5,7 Attempts to obtain meaningful correlations with the Mn-NTCNE and Mn · · · Mn distances or the Mn-Mn-NTCNE angle were unsuccessful.8 The intrachain magnetic coupling originates from the direct overlap between the orbitals of the bonded [Mn(porphyrin)]+ and [TCNE]•- radicals and depends upon the solvent and substitution on the aromatic rings.5,7,8 Solvates and their desolvation products have different values of Jintra, as well as

10.1021/jp105109d  2010 American Chemical Society Published on Web 09/22/2010

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TABLE 1: Summary of the Structurala and Magnetic Properties of [MnTClPP][TCNE] · xSolb solvent, S x θ′, K9 Jintra/kB, K9 Jintra, cm-1 9 χ′maxd (Tc), K9 Mn · · · Mn, interchain, Å Mn-NTCNE, Å interchain, Å, I-II Mn · · · Mn, interchain, Å, I-II Mn · · · Mn, interchain, Å, I-II interchain, Å, I-III Mn · · · Mn, interchain, Å, I-III Mn · · · Mn, interchain, Å, I-III interchain, Å, I-IV Mn · · · Mn, interchain, Å, I-IV Mn · · · Mn, interchain, Å, I-IV interchain, Å, II-III Mn · · · Mn, interchain, Å, II-III Mn · · · Mn, interchain, Å, II-III Mn-N-C, deg MnN4- TCNE, deg

PhMe, 2a 9

2 13 -33 -23 8.8 10.189 2.267 13.85 14.52 15.22 9.46 10.17 11.46 17.06 17.08 19.55 16.48 16.61 18.36 167.2 86.8

PhMe, 2a′ 0 29 -65 -45 6.7 10.1426(3) 2.20(6) 11.43 12.5074(6) 12.5074(6) 9.73 10.9697(4) 10.9697(4) 14.68 14.6792(7) 14.6792(7) 15.3358(7) 15.3358(7) 15.3358(7) 165.5(34) 74.1(3)

% changec

CH2Cl2, 2b′

% changec

2 58 -160 -111 14.1 9.894 2.276 10.70 10.70 14.57 12.73 13.00 14.65

0 86 -265 -184 10.8 9.5196(2) 2.31(2) 10.71 10.7091(2) 14.3286(2) 12.35 13.0423(2) 13.4444(2)

3.8 2.0 -0.1 -0.1 1.6 3.0 -0.3 8.2

12.73 13.00 14.65 143.1 52.4

12.35 13.0423(2) 13.4444(2) 125.9(23) 36.6(2)

3.0 -0.3 8.2 12.1 30.5

CH2Cl2, 2b 9

0.5 3.1 17.5 13.8 17.8 -2.9 -7.9 4.3 14.0 14.1 24.9 6.9 7.6 0.2 1.0 14.6

a A few typographical errors in the distances reported in reference9 have been corrected. b x ) 0, 2; Sol ) PhMe, CH2Cl2. c The values from the × ) 0 were subtracted from × ) 2. d The temperature at which χ′(T) has a maximum at 10 Hz.

different Tc’s. For example, five pseudopolymorphs of [MnTClPP][TCNE] · 2Sol (2 · 2Sol) [MnTClPP ) 1 (R ) Cl); H2TClPP ) meso-tetrakis(4-chlorophenyl)porphyrin] have been reported,9 and desolvation enhances the magnetic coupling (θ′ and Jintra) but attenuates the ordering temperatures (Tc) (Table 1). For Sol ) PhMe (2a), θ′ ) 13 K and Tc ) 8.8 K, and for the Sol ) CH2Cl2 (2b), θ′ ) 58 K and Tc ) 14.1 K. Desolvation of the latter led to 2b′ with θ′ ) 86 K (and a Tc of 10.8 K), whereas desolvation under different conditions of 2a led to two additional phases, namely, ones with θ′ ) 29 and 92 K (2a′) and 6.7 and 11.1 K Tcs, respectively.9 To validate and to obtain a more detailed correlation, it is essential to include the magnetostructural data from the desolvated phases with those obtained from the structurally characterized solvates of 2. The crystal structure determinations of the desolvated phases have been thwarted by the lack of single crystals as a consequence of the preparative procedure (thermolysis). Nonetheless, the polycrystalline desolvated phases diffract, and herein, we report the structures solved by the ab initio determination method (simulated annealing) followed by Rietveld refinements of the X-ray powder diffraction (XRPD) data of desolvated [MnTClPP][TCNE] · 2Sol (2a′ prepared from the Sol ) PhMe; 2b′, from CH2Cl2) and correlate their magnetic properties to the structure and the solvated phases [MnTClPP][TCNE] · 2Sol (2). Experimental Section General Procedures. [MnTClPP][TCNE] · xSol [x ) 0; Sol ) PhMe (2a′), CH2Cl2 (2b′)] were prepared as previously reported.9 Confirmation that they were the correct polymorphs was successfully made by comparing the frequency dependencies of the ac susceptibility, χ′(T) and χ′′(T), below 15 K. X-ray Structure. The specimens were prepared by sealing the polycrystalline samples in a thin-walled capillary under an inert atmosphere, and high-resolution powder diffraction patterns were collected at X16C beamline of the National Synchrotron Light Source, Brookhaven National Laboratory. A Si(111) channel-cut monochromator selected the 0.605 99(7) Å highly parallel incident beam. The diffracted X-rays were analyzed

using a Ge(111) single-reflection crystal and detected using a NaI scintillation counter. The wavelength and diffractometer zero position were calibrated by measuring a sample of NIST standard reference material 1976 (sintered plate of Al2O3). All measurements were performed at room temperature, and the capillaries were rotated during data collection for better averaging of the powder pattern. The TOPAS-Academic (TA) program was used to index, solve, and refine the crystal structure.10-12 The space group was hypothesized by checking the systematic absences of Pawley whole profile fitting. On the basis of the structure of the solvated single crystals,9 both the central Mn atom of the porphyrin molecule and the center of the TCNE were expected to reside on crystallographic inversion centers. Direct space searching (simulated annealing) was used to solve the structure, fixing the Mn atom and geometric center of TCNE molecule at two distinct inversion centers. The starting structure model was generated from the previously reported single crystal structures of 2a and 2b.9 After obtaining good agreement between the observed and calculated XRPD patterns with rigid body molecules, Rietveld refinements were used to improve the fits and optimize the atomic positions. When compared to the number of structural parameters to be determined, the X-ray powder diffraction patterns of these samples, however, do not provide sufficient information to determine every atom position independently. Consequently, restraints keeping the atoms within a reasonable molecular shape were used. The molecular structures were described with the z-matrix formalism in TA, which allows use of bonding distances, angles, and torsion angles as structural parameters. The z-matrix also permits the point symmetry of the TCNE moiety to be fixed as D2h. It is not known that this species in this environment has such high point symmetry, but allowing lower symmetries did not significantly improve the quality of the Rietveld fit. Furthermore, TA allows structural parameters to be refined within chemically meaningful ranges. We imported relevant limit values from the MOGUL database.13 These restrictions may bias the molecular geometry, but the R-factor decrease by removing those limits was not significant, and

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Her et al. TABLE 2: Summary of Crystallographic Parameters for [MnTClPP][TCNE] · xSola S x a, Å b, Å c, Å R, deg β, deg γ, deg V, Å3 Z space group Fcalcd, g/cm3 Rp, % Rwp, % T, K GOF (Rwp/Rexp) a

Figure 1. High-resolution synchrotron powder diffraction data and Rietveld fits to the data for 2a′ (top) and 2b′ (bottom). The lower traces of each plot are the differences (measured - calculated) plotted to the same vertical scale.

Fourier difference maps do not show any significant features. Four independent displacement parameters (IDP) were used for each structure model: Mn, Cl, C, and N atoms (together) in [MnTClPP]+, and all atoms in [TCNE]•-. All H atoms were attached to their associated carbon atoms in porphyrin and phenyl rings using the z-matrix and set to have the same IDP. Results and Discussion Description of the Structures. The structures of 2a′ and 2b′ were determined by analysis of the synchrotron powder diffraction data on the basis of the chemical composition, as discussed in the experimental procedure. The Rietveld refinement fits to the data are shown in Figure 1, and the crystallographic parameters are summarized in Table 2. Both structures have fully ordered [MnTClPP][TCNE] with both the cations and anion residing on a center of symmetry, Figure 2. The intracation distances are similar to that reported for [MnTClPP]+ 9 as well as other [MnIII(porphyrin)]+ cations.14 The [TCNE]•-’s are planar with central intra-[TCNE]•- C-C bond distances of 1.29(9) and 1.25(4) Å. [TCNE]•-’s are uniformly trans-µ-N-σ-bound to two MnIII’s, forming parallel 1-D · · · D+A•-D+A•- · · · [D ) MnTClPP; A ) TCNE], as occurs for the entire family of [MnIII(porphyrin)][TCNE] ferrimagnets (Figure 2).2 The [TCNE]•- N-Mn distances are 2.20(6), and 2.32(2) Å for 2a′ and 2b′, respectively. These are shorter by 3.1 and 2.0% with respect to the solvated counterparts, indicative of contraction upon desolvation.15 The Mn-N-C angles are 165.6° and 125.8° and are reduced by 1.6° and 17.3° with respect to the solvated counterparts. Also reduced in value are the dihedral angles between the mean Mn(N4)TPP and the [TCNE]•- planes, which are 74.1° and 36.4°,

PhMe 9

2 2a 10.171(4) 10.189(3) 14.522(3) 107.51(2) 85.58(2) 111.51(3) 1334.4(7) 1 P1j 1.391 4.26 8.31 193

PhMe 0 2a′ 19.454(2) 10.143(1) 22.866(3) 90 92.54(1) 90 4508(2) 4 C2/c 1.376 4.69 5.98 295 1.284

CH2Cl2 9

2 2b 9.894(2) 10.697(2) 23.560(5) 90 101.34(2) 90 2444.6(8) 2 P21/n 1.499 4.11 10.34 193

CH2Cl2 0 2b′ 9.519(1) 10.710(1) 22.280(3) 90 92.88(1) 90 2268.5(8) 2 P21/n 1.367 4.78 6.07 295 1.649

x ) 0, 2;9 Sol ) PhMe, CH2Cl2.

respectively. These values are 14.6 and 30.5% smaller than for 2a and 2b and are the most significant structural changes that are observed upon desolvation. Although these values are in the range observed for related compounds, their reduced and different values correlate with the different intrachain magnetic couplings observed for these materials (vide infra). The arrangements of the unique parallel chains are shown in Figures 3 and 4 for 2a′ and 2b′, respectively. These respective arrangements are qualitatively very similar to that of the parent solvate with four and three unique nearest-neighbor chain interactions of 2a′ and 2b′, respectively. This suggests that upon solvent loss, minimal packing rearrangements occur. The perpendicular distances between parallel chains (interchain separations) as well as the interchain Mn · · · Mn separations are listed in Table 1. Loss of PhMe leads to a space group change from P to C2/c for 2a′. Hence, although the arrangement of the parallel chains (Figure 3) is qualitatively similar for 2a and 2a′, the relative relationships are altered. For 2a, three chain pairs are out-of-registry, and one chainpair is in-registry with respect to each other.9 However, for 2a′, two chain pairs (I-II and I-III) are out-of-registry, and two chain pairs (II-III and I-IV) are in-registry with respect to each other (Figure S1 of the Supporting Information and Table 2). Upon loss of PhMe from 2a, the separation between chains I-II, I-IV, and II-III decreases by 17.5, 14.0, and 6.8% respectively. This is due to the loss of the PhMe solvent in layers between the planes defined by I-III and II-IV. In contrast, the separation between chains I-III increased from 8.86 to 9.73 Å (9.8%) due to shifting of the chains. The Mn · · · Mn separations may either increase or decrease upon solvent loss. Because PhMe loss reduces the interchain I-II separation, there is a corresponding reduction in the Mn · · · Mn separations to 12.51 Å from 14.52 and 20.09 Å. For chains II-III, however, the Mn · · · Mn separations increase to 18.39 Å from 16.62 and decrease to 18.37 Å. Although chains I-III and I-IV both increase and decrease upon solvent loss, their corresponding Mn · · · Mn separations increase and decrease to 10.97 and 17.84 Å, respectively. In contrast, the space group does not change upon desolvation of 2b, and the in-registry chain pair I-II and the out-of-registry chain pair I-III (and equivalently II-III) remain unaltered (Figure S2 of the Supporting Information and Table 2). The separation between chains I-II is not

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Figure 2. Segment of the chain structure for 2a′ and 2b′.

Figure 3. View along the chain (b) axis for 2a′ showing the interchain interactions.

altered upon solvent loss for 2b; however, the separation between chains I-III (and equivalently, II-III) decreases by 3% from 12.73 to 12.35 Å upon loss of CH2Cl2 because the solvent resides between the layers defined by chains I-II and III-III′. The Mn · · · Mn separations decrease or remain about the same; however, they do slightly decrease by 1.6% between chains I-III, which increases in length a small amount upon desolvation. Overall, upon desolvation of 2a and 2b to 2a′ and 2b′, respectively, two different polymorphs quantitatively form, and there is no evidence of mixtures from the diffraction data. The unit cell and packing motifs closely resemble that of the solvates. The intrachain distances decrease, and the [TCNE]•- assumes a different orientation with respect to the solvate as well as the other desolvate ( see Figure 5). The largest changes are observed for the dihedral angle between

the mean Mn(N4)TPP and [TCNE]•- planes. The interchain separations generally decrease upon desolvation, with the greatest decrease observed in the direction from which the solvent is lost. The relative positions of the chains shift with respect to each other, and the Mn · · · Mn separations, although generally decreasing, sometimes increase. Correlation of the Magnetic Properties. As noted earlier and quantified in Table 1, each solvate magnetically orders as a ferrimagnet, but exhibits different magnetic properties that upon loss of solvent leads to (a) an enhancement the intrachain coupling as measured by either the θ′ or Jintra taken from a fit observed χT(T) data to the Seiden expression and (b) Tc is suppressed.9 With the availability of structural parameters for 2a′ and 2b′, a more detailed magnetostructural correlation can be established.

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Figure 4. View along the chain (a) axis for 2b′ showing the interchain interactions.

Figure 5. Overlay view of the intrachain orientations of the 2a (red), 2a′ (green), 2b (blue), and 2b′ (purple) showing the orientation (top) and dihedral angle (bottom) of the [TCNE]•- with and without solvent.

The best, and essentially equivalent, correlations occur between the intrachain coupling and either the dihedral angle between the mean Mn(N4)TPP-[TCNE]•- planes or the Mn-(N-C)TCNE angle (Figure 6).16 The lower values of either of these angles correlate with stronger coupling. Hence, systems with reduced Mn(N4)TPP-[TCNE]•- dihedral angles and Mn-(N-C)TCNE angles are sought for the design of new magnets with enhanced magnetic properties; however, they cannot be a priori designed. This enhancement of intrachain coupling with angle is in accord with the dominant overlap

leading to spin coupling arising from the MnIII dz2-like SOMO and the z-component of the [TCNE]•- π* (πz*) SOMO (Figure 7). When [TCNE]•- is perpendicular to the Mn(N4)TPP, there is no πz* to overlap with the MnIII dz2-like SOMO. Hence, the coupling is weak, as observed for 2a.5 When the MnNC angle is 180°, then there is no πz* component, and upon reduction of this angle, πz* becomes finite and increases, leading to the greater overlap and spin coupling in accord with the observed increase in θ′ and Jintra. Attempts to correlate the intra- and interchain Mn · · · Mn separations and

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Figure 6. Correlation occurs between the intrachain coupling [θ′ (b) and Jintra (2)] and either the dihedral angle between the mean Mn(N4)TPP and [TCNE]•- planes (a), or the Mn-(N-C)TCNE angle (b).16

fits of the magnetic data to both the Curie-Weiss and Seiden expressions.

Figure 7. Illustration of the overlap leading to spin coupling arising from the MnIII dz2-like and πz*-[TCNE]•- SOMOs.

the Mn-NTCNE distance with either θ′ or Jintra were unsuccessful. The identification of a correlation with Tc and structural parameters, however, remains elusive. Magnetic ordering is a bulk phenomenon that includes contributions from interchain coupling in addition to intrachain coupling.7,17 From the evaluation of the interchain Mn · · · Mn separations as a function of solvent loss, it is clear that although some separations get closer and most likely lead to enhanced interchain coupling that should contribute to an enhanced Tc, others do the opposite. Further insight and modeling is needed to correlate the interchain couplings, in addition to the intrachain couplings, with Tc, and the structural data provided herein should be important in this future endeavor. Conclusion Thermolysis of [MnTClPP][TCNE] · 2Sol (sol ) PhMe, CH2Cl2) forms two desolvated polymorphs (2a′ and 2b′) that are different and related to the structure of their solvates. The most significant structural difference among the four structures is the dihedral angle between the mean Mn(N4)TPP and [TCNE]•planes and the Mn-(N-C)TCNE angle. From this, a magnetostructural correlation between the intrachain coupling and both the dihedral angle between the mean Mn(N4)TPP and [TCNE]•planes and Mn-(N-C)TCNE angles is validated. Hence, the intrachain coupling is primarily attributed to occur from the overlap of MnIII dz2-like and the [TCNE]•- πz* SOMOs. As the dihedral angle between the mean Mn(N4)TPP and [TCNE]•planes and Mn-(N-C)TCNE angle deceases, this overlap increases, as does the intrachain couplings, as determined from

Acknowledgment. We appreciate the continued support in part by the Department of Energy Division of Material Science (Grants nos. DE-FG03-93ER45504 and DE-FG02-01ER4593). Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract no. DE-AC02-98CH10886. This paper is dedicated to Mark A. Ratner for his innumerable contributions to chemistry and his unwavering friendship. Supporting Information Available: The structures reported in this paper have been deposited with the Cambridge Crystallographic Data Center as Supplementary Publication CCDC Nos. 775930 and 775931. Copies of the data can be obtained free of charge on application to The Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (Fax: +44 1223 336 033; e-mail: [email protected] or on the web www: http://www.cam. ac.uk). This material is available free of charge via the Internet at http://pubs.acs.org. References and Notes (1) Miller, J. S. AdV. Mater. 2002, 14, 1105. Day, P. Notes Rec. R. Soc. Lond. 2002, 56, 95. (2) Miller, J. S.; Epstein, A. J. Chem. Commun. 1998, 1319. Blundell, S. J.; Pratt, F. L. J. Phys.: Condens. Matter 2004, 16, R771. Crayson, J. A.; Devine, J. N.; Walton, J. C. Tetrahedron 2000, 56, 7829. Ovcharenko, V. I.; Sagdeev, R. Z. Russ. Chem. ReV. 1999, 68, 345. Kinoshita, M. Philos. Trans. R. Soc. London (A) 1999, 357, 2855. Plass, W. Chem. Unserer Zeit. 1998, 32, 323. Day, P. J. Chem. Soc., Dalton Trans. 1997, 701. Miller, J. S.; Epstein, A. J. Chem. Eng. News 1995, 73 (40), 30. Miller, J. S.; Epstein, A. J. AdV. Chem. Ser. 1995, 245, 161. Miller, J. S.; Epstein, A. J. Angew. Chem., Int. Ed. Engl. 1994, 33, 385. Kahn, O. AdV. Inorg. Chem. 1995, 43, 179. Kinoshita, M. Jpn. J. Appl. Phys. 1994, 33, 5718. (l) Gatteschi, D. AdV. Mater. 1994, 6, 635. (3) Rittenberg, D. K.; Arif, A. M.; Miller, J. S. J. Chem. Soc., Dalton Trans. 2000, 3939. (4) Rittenberg, D. K.; Sugiura, K.-i.; Sakata, Y.; Mikami, S.; Epstein, A. J.; Miller, J. S. AdV. Mater. 2000, 12, 126. (5) Brandon, E. J.; Kollmar, C.; Miller, J. S. J. Am. Chem. Soc. 1998, 120, 1822. (6) Seiden, J. J. Phys., Lett. 1983, 44, L947. (7) Ribas-Arin˜o, J.; Novoa, J. J.; Miller, J. S. J. Mater. Chem. 2006, 16, 2600.

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(8) Brandon, E. J.; Miller, J. S. In NATO ARW Supramolecular Engineering of Synthetic Metallic Materials: Conductors and Magnets; Veciana, J., Rovira, C., Amabilino, D., Eds.; 1998; C518; 197. (9) Brandon, E. J.; Rittenberg, D. K.; Arif, A. M.; Miller, J. S. Inorg. Chem. 1998, 37, 3376. (10) Bruker AXS. TOPAS V3: General profile and structure analysis software for powder diffraction data. User’s Manual; Bruker AXS: Karlsruhe, Germany; 2005. (11) Coelho, A. A. J. Appl. Crystallogr. 2000, 33, 899. (12) TOPAS-Academic is available at http://www.topas-academic.net. (13) Bruno, I. J.; Cole, J. C.; Kessler, M.; Luo, J.; Motherwell, D. S.; Purkis, L. H.; Smith, B. R.; Taylor, R.; Cooper, R. I.; Harris, S. E.; Orpen, A. G. J. Chem. Inf. Comput. Sci. 2004, 44, 2133. (14) Hibbs, W.; Rittenberg, D. K.; Sugiura, K.-i.; Burkhart, B. M.; Morin, B. G.; Arif, A. M.; Liable-Sands, L.; Rheingold, A. L.; Sundaralingam, M.; Epstein, A. J.; Miller, J. S. Inorg. Chem. 2001, 40, 1915. Miller, J. S.; Epstein, A. J. Chem. Commun. 1998, 1319. Goldberg, I.; Krupitsky, H.; Stein, Z.; Hsiou, Y.; Strouse, C. E. Supramol. Chem. 1995, 4, 203. Krupitsky, H.; Stein, Z.; Goldberg, I. J. Inclusion Phenom. Mol. Recognit. 1995, 20, 211. Goldberg, I. Mol. Cryst. Liq. Cryst. 1996, 278, 767. Byrn, M. P.; Curtis, C. J.; Hsiou, Y.; Kahn, S. I.; Sawin, P. A.; Tendick, S. K.; Terzis, A.; Strouse, C. E. J. Am. Chem. Soc. 1993, 115, 9480. Rittenberg, D. K.; Sugiura, K.-i.; Sakata, Y.; Mikami, S.; Epstein, A. J.; Miller, J. S. AdV. Mater. 2000, 12, 126. Rittenberg, D. K.; Sugiura, K.-i.; Sakata, Y.; Guzei, I. A.; Rheingold, A. L.; Miller, J. S. Chem.sEur. J. 1999, 5, 1874. ¨ hrstrom, L.; Sugiura, K.-i.; Arif, A. M.; Rittenberg, D. K.; Schweizer, J.; O Epstein, A. J.; Miller, J. S. Chem.sEur. J. 1997, 3, 138. Brandon, E. J.; Sugiura, K.-i.; Arif, A. M.; Liable-Sands, L.; Rheingold, A. L.; Miller, J. S. Mol. Cryst., Liq. Cryst. 1997, 305, 269. Brandon, E. J.; Burkhart, B. M.;

Her et al. Rogers, R. D.; Miller, J. S. Chem.sEur. J. 1998, 4, 1938. Brandon, E. J.; Arif, A. M.; Burkhart, B. M.; Miller, J. S. Inorg. Chem. 1998, 37, 2792. (l) Brandon, E. J.; Arif, A. M.; Miller, J. S.; Sugiura, K.-i.; Burkhart, B. M. Crystal Eng. 1998, 1, 97. Sugiura, K.-i.; Mikami, S.; Tanaka, T.; Sawada, M.; Manson, J. L.; Miller, J. S.; Sakata, Y. Chem. Lett. 1997, 1071. Day, V. W.; Sults, B. R.; Tasset, E. L.; Marianelli, R. S.; Boucher, L. J. Inorg. Nucl. Chem. Lett. 1975, 11, 505. Cheng, B.; Cukiernik, F.; Fries, P.; Marchon, J.-C.; Scheidt, W. R. Inorg. Chem. 1995, 34, 4627. Guildard, R.; Perie, K.; Barbe, J.-M.; Nurco, D. J.; Smith, K. M.; Caemelbecke, E. V.; Kadish, K. M. Inorg. Chem. 1998, 37, 973. Landrum, J. T.; Hatano, K.; Scheidt, W. R.; Reed, C. A. J. Am. Chem. Soc. 1980, 102, 6729. Hill, C. L.; Williamson, M. M. Inorg. Chem. 1985, 24, 3024. Fleischer, E. B. Acc. Chem. Res. 1970, 3, 105. Scheidt, W. R.; Reed, C. A. Chem. ReV. 1981, 81, 543. Turner, P.; Gunter, M. J.; Hambley, T. W.; White, A. H.; Skelton, B. W. Inorg. Chem. 1992, 32, 2297. (15) Note that the desolvated structures were obtained at room temperature (whereas that of the solvated structures was obtained at low temperature) and at room temperature should have even longer Mn-N distances. (16) Linear correlations between the Mn(N4)TPP-[TCNE]•- dihedral angle, f, and q′ [q′ ) 136.04-1.433f] and J ) [q′ ) 417.81-4.598f] have regression fits of 99.8 and 98.7%, respectively. The linear correlations between the Mn-N-C angle, φ′, and θ′[θ′ ) 288.42-1.433φ] and J ) [θ′ ) 921.27-5.2552φ′] have regression fits of 98.5 and 99.4%, respectively. (17) Wynn, C. M.; Gıˆrtu, M.; Brinckerhoff, W. B.; Sugiura, K.-i.; Miller, J. S.; Epstein, A. J. Chem. Mater. 1997, 9, 2156.

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