Structure and magnetic properties of (meso-tetraphenylporphinato) manganese(III) bis(dithiolato)nickelates

Article abstract of DOI:10.1021/ic050980u

The crystal structures of [MnTPP]{Ni[S₂C₂H(CN)] ₂} [MnTPP = (meso-tetraphenylporphinato)manganese(III)] and [MnTPP]{Ni[S₂C₂(CN)₂]₂} have been determined. These salts possess trans-μ-coordination of S = 1/2 {Ni[S ₂C₂H(CN)]₂}?^- and {Ni[S ₂C₂(CN)₂]₂}?^- to Mn(III) and form parallel 1-D coordination polymer chains exhibiting ν_CN at 2210 and 2200 and 2220 and 2212 cm^-1, respectively. The bis(dithiolato) monoanions are planar and bridge two cations with MnN distances of 2.339(16), and 2.394(3) A, respectively, which are comparable to related MnN distances observed for [MnTPP][TCNE]?x(solvates). In addition, [MnTP′P]{Ni[S₂C₂(CN)₂] ₂} {H₂TP′P = mesotetrakis[3,5-di-tert-butyl-4- hydroxyphenyl)porphyrin] and [MnTP′P(OH₂)]{Ni[S ₂C₂(CN)₂]₂} were prepared. The latter forms isolated paramagnetic ions. The room-temperature values of χ T for 1-D [MnTPP]{Ni[S₂C₂H(CN)]₂}, [MnTPP]-{Ni[S₂C₂(CN)₂]₂}, and [MnTP′P]{Ni[S₂C₂(CN)₂]₂} are 2.55, 3.28, and 2.86 emu K/mol, respectively. Susceptibility (χ) measurements between 2 and 300 K reveal weak antiferromagnetic interactions with Θ = -5.9 and -0.2 K for [MnTPP]{Ni[S₂C₂H(CN)] ₂} and [MnTPP]{Ni[S₂C₂(CN)₂] ₂}, respectively, and stronger antiferromagnetic coupling of -50 K for [MnTP′P]{Ni[S₂C₂(CN)₂]₂} from fits of χ(T) to the Curie-Weiss law. The 1-D intrachain coupling, J_intra of [MnTPP]{Ni[S₂C₂H(CN)]₂} and [MnTPP]{Ni[S₂C₂(CN)₂]₂} was determined from modeling χT(T) by the Seiden expression (H = -2JS _i·S_i) with J/k_B = -8.00 K (-5.55 cm ^-1; -0.65 meV) for [MnTPP]{Ni[S₂C₂H(CN)] ₂}, J/k_B = -3.00 K (-2.08 cm^-1; -0.25 meV) for [MnTP′P]{Ni[S₂C₂(CN)₂]₂}, and J/k_B = -122 K (-85 cm^-1) for [MnTP′P]-{Ni[S ₂C₂(CN)₂]₂}. These observed negative J_intra/k_B values are indicative of antiferromagnetic coupling. These materials order as ferrimagnets at 5.5,2.3, and 8.0 K, for [MnTPP]{Ni[S₂C₂H(CN)]₂}, [MnTPP]{Ni[S ₂C₂(CN)₂]₂}, and [MnTP′P]-{Ni[S₂C₂(CN)₂]₂}, respectively, based upon the temperature at which maximum in the 10 Hz χ′(T) data occurs. [MnTP′P]{Ni[S₂C ₂(CN)₂]₂} has a coercivity of 17 700 Oe and remanent magnetizations of 7250 emu Oe/mol at 2 K and 17 Oe and 850 emu Oe/mol at 5 K; hence, upon cooling it goes from being a soft magnet to being a very hard magnet.

Full text of DOI:10.1021/ic050980u

Inorg. Chem. 2005, 44, 7530−7539
Structure and Magnetic Properties of
(meso-Tetraphenylporphinato)manganese(III) Bis(dithiolato)nickelates
Louise N. Dawe,† Jesse Miglioi,† Laura Turnbow,† Michelle L. Taliaferro,† William W. Shum,†
Joshua D. Bagnato,† Lev N. Zakharov,‡ Arnold L. Rheingold,‡ Atta M. Arif,† Marc Fourmigue´,§ and
Joel S. Miller*,†
Department of Chemistry, UniVersity of Utah, 315 S. 1400 East, RM 2020,
Salt Lake City, Utah 84112-0850, Laboratoire Chimie Inorganique, Mate´riaux et Interfaces
(CIMI), FRE 2447, CNRS-UniVersite´ d’Angers, 49045 Angers, France, and Department of
Chemistry, UniVersity of California, San Diego, 9500 Gilman DriVe, La Jolla, California 92093
Received June 15, 2005
The crystal structures of [MnTPP]
[MnTPP] Ni[S2C2(CN)2]2 have been determined. These salts possess trans-
Ni[S2C2H(CN)]2}•- and Ni[S2C2(CN)2]2}•- to Mn(III) and form parallel 1-D coordination polymer chains exhibiting
{
{
Ni[S2C2H(CN)]2
}
[MnTPP
)
(meso-tetraphenylporphinato)manganese(III)] and
{
}
µ
-coordination of 1/2
S )
{
νCN at 2210 and 2200 and 2220 and 2212 cm-1, respectively. The bis(dithiolato) monoanions are planar and
bridge two cations with MnN distances of 2.339(16), and 2.394(3) Å, respectively, which are comparable to related
MnN distances observed for [MnTPP][TCNE]
tetrakis[3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin] and [MnTP
forms isolated paramagnetic ions. The room-temperature values of
Ni[S2C2(CN)2]2 , and [MnTP P] Ni[S2C2(CN)2]2 are 2.55, 3.28, and 2.86 emu K/mol, respectively. Susceptibility
) measurements between 2 and 300 K reveal weak antiferromagnetic interactions with Θ ) −5.9 and 0.2 K for
, respectively, and stronger antiferromagnetic coupling of
‚
x(solvates). In addition, [MnTP
P(OH2)] Ni[S2C2(CN)2]2
T for 1-D [MnTPP]
′
P]
{
Ni[S2C2(CN)2]2} {H2TP
were prepared. The latter
Ni[S2C2H(CN)]2 , [MnTPP]-
′P ) meso-
′
{
}
{
ø
}
{
}
′
{
}
(
ø
−
[MnTPP]
50 K for [MnTP
of [MnTPP] Ni[S2C2H(CN)]2
{
Ni[S2C2H(CN)]2
P] Ni[S2C2(CN)2]2
and [MnTPP]
Sj) with J/kB ) −8.00 K (
0.25 meV) for [MnTP P]
}
and [MnTPP]
{
Ni[S2C2(CN)2]2
}
−
′
{
}
from fits of
ø
(T) to the Curie
−
Weiss law. The 1-D intrachain coupling, Jintra
,
{
}
{
Ni[S2C2(CN)2]2
5.55 cm-
Ni[S2C2(CN)2]2
} was determined from modeling øT(T) by the Seiden
1
expression (H ) −2JSi
‚
−
{
;
−
}
0.65 meV) for [MnTPP]
, and J/kB ) −122 K (
{
−
Ni[S2C2H(CN)]2
}
, J/kB
)
P]-
1
−
3.00 K (
Ni[S2C2(CN)2]2
order as ferrimagnets at 5.5, 2.3, and 8.0 K, for [MnTPP]
Ni[S2C2(CN)2]2 , respectively, based upon the temperature at which maximum in the 10 Hz ø′(T) data occurs.
[MnTP P] Ni[S2C2(CN)2]2 has a coercivity of 17 700 Oe and remanent magnetizations of 7250 emu Oe/mol at 2
−
2.08 cm-
;
−
′
85 cm-1) for [MnTP
′
{
}. These observed negative Jintra/kB values are indicative of antiferromagnetic coupling. These materials
{
Ni[S2C2H(CN)]2 , [MnTPP] Ni[S2C2(CN)2]2 , and [MnTP P]-
}
{
}
′
{
}
′
{
}
K and 17 Oe and 850 emu Oe/mol at 5 K; hence, upon cooling it goes from being a soft magnet to being a very
hard magnet.
Introduction
based magnets typified by [MnTPP][TCNE]‚2PhMe (H2TPP
) meso-tetraphenylporphyrin) were discovered3a,7 Subse-
quently, a wide range of manganese porphyrin compounds
The study of magnetically ordered molecule-based materi-
als is a growing area of contemporary chemistry.2-4 The first
organic-containing molecule-based magnet, [Fe(C5Me5)2]•+[TC-
NE]•- (TCNE ) tetracyanoethylene), and has an ordering
temperature, Tc, of 4.8 K.5 Improvements led to the discovery
of V(TCNE)x•y(solvent), the first room-temperature organic
magnet (Tc ∼ 400 K).6 Later a family of metallomacrocycle-
(1) (a) Miller, J. S., Dougherty, D., Eds. Proceedings on the Conference
on Ferromagnetic and High Spin Molecular Based Materials. Mol.
Cryst. Liq. Cryst. 1989, 176. (b) Kahn, D., Gatteschi, J. S., Miller, F.,
Palacio, O., Eds. Proceedings on the Conference on Molecular
Magnetic Materials. NATO ARW Mol. Magn. Mater. 1991, E198. (c)
Iwamura, H., Miller, J. S., Eds. Proceedings on the Conference on
the Chemistry and Physics of Molecular Based Magnetic Materials.
Mol. Cryst. Liq. Cryst. 1993, 232/233. (d) Miller, J. S., Epstein, A. J.,
Eds. Proceedings on the Conference on Molecule-Based Magnets. Mol.
Cryst. Liq. Cryst. 1995, 271-274. (e) Itoh, K., Miller, J. S., Takui,
T., Eds. Proceedings on the Conference on Molecular-Based Magnets.
Mol. Cryst. Liq. Cryst. 1997, 305/306. (f) Turnbull, M. M., Sugimoto,
T., Thompson, L. K., Eds. ACS Symp. Ser. 1996, No. 644.
* To whom correspondence should be addressed. E-mail:
jsmiller@chem.utah.edu.
† University of Utah.
‡ CNRS-Universite´ d’Angers.
§ University of California, San Diego.
7530 Inorganic Chemistry, Vol. 44, No. 21, 2005
10.1021/ic050980u CCC: $30.25
© 2005 American Chemical Society
Published on Web 09/14/2005

[MnTPP]{Ni[S2C2H(CN)]2}
has been structurally characterized with [TCNE]•- trans-µ-
N-σ-bound to MnIII forming a 1-D coordination polymer
consisting of parallel chains of alternating ‚‚‚D+A•-D+A•-‚‚‚
(D ) MnTPP; A ) radical anion).3a These materials are
ferrimagnets resulting from the antiferromagnetic coupling
of the S ) 2 MnIII with S ) 1/2 [TCNE]•- with critical
temperatures, Tc, ranging from 3.5 to 28 K.3a,8 Furthermore,
at low temperature they exhibit complex magnetic behaviors
that include large coercivities in the range of 27 kOe.9 Herein,
we extend the A•- to bis(2-cyano-1,2-ethanedithiolato)-
nickelate(III) (1) {Ni[S2C2H(CN)]2}•- 10 and (bis(maleoni-
trile)dithiolato)nickelate(III) (2) {Ni[S2C2(CN)2]2}•-.11,12 2 is
of particular interest as it has been reported as [NH4]2‚H2O
to magnetically order as a weak ferromagnetic at 4.9 K.13
Furthermore, while magnetic order has not been reported for
metallocenium salts of 2, they frequently exhibit ferromag-
netic coupling14 and decamethymanganocenium salts of
{Ni[S2C2(CF3)2]2}•- order as metamagnets.14,15 Herein,
[MnTPP]{Ni[S2C2H(CN)]2} and [MnTPP]{Ni[S2C2(CN)2]2}
have been prepared and are reported. Additionally, due to
the increased steric constraints of substitution of the phenyl
rings in the 3,5-positions with tert-butyl groups, higher
magnetic ordering temperatures have been observed;16,17
hence, [MnTP′P]{Ni[S2C2(CN)2]2} (H2TP′P ) meso-tetrakis-
(3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin) was prepared
and its magnetic properties compared to [MnTPP]{Ni[S2C2H-
(CN)]2} and [MnTPP]{Ni[S2C2(CN)2]2}.
Experimental Section
Synthesis. Solvents for the preparation of manganese porphyrins
were used as received. Solvents used for preparation of the electron-
transfer salts were distilled under nitrogen from appropriate drying
agents before use, and the syntheses of electron-transfer salts were
carried out in inert atmosphere DriLab or using standard Schlenck
vacuum techniques. TCNQF4 was obtained as a gift from the Du
Pont Co. and was recrystallized from CH2Cl2 prior to use. [NBu4]-
{Ni[S2C2(CN)2]2}11b and [HNMe3]{Ni[S2C2H(CN)]2}10 were syn-
thesized according to literature procedures. Pyrrole was dried by
vacuum distillation from CaH2.
All free-base porphyrins were prepared by the Adler-Longo
method that involves refluxing pyrrole and the appropriately
substituted benzaldehyde in propionic acid for 30 min.18 Chlorin
impurities were removed via the metalation of the corresponding
free-base porphyrins. Relative purity was confirmed by thin-layer
chromatography and/or UV-visible spectroscopy. The free-base
porphyrins were metalated according to the literature19 method by
reaction with MnI2 in dichloromethane stabilized with triethylamine.
The products were purified via boiling in toluene to remove the
triethylamine and then recrystallized from CH2Cl2/MeOH. MnTPP
and MnTP′P were further purified by dynamic vacuum sublimation
at 325 °C and 50 mTorr.
(2) Reviews: (a) Miller, J. S.; Epstein, A. J. Chem. Commun. 1998, 1319.
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A. J. Chem. Eng. News 1995, 73 (No. 40), 30. (e) Miller, J. S.; Epstein,
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Jpn. J. Appl. Phys. 1994, 33, 5718. (g) Miller, J. S.; Epstein, A. J.
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J. H.; Reiff, W. M. J. Chem. Soc., Chem. Commun. 1986, 1026. Miller,
J. S.; Calabrese, J. C.; Rommelmann, H.; Chittipeddi, S.; Zhang, J.
H.; Reiff, W. M.; Epstein, A. J. J. Am. Chem. Soc. 1987, 109, 769.
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J. S. Science 1991, 252, 1415. (b) Epstein, A. J.; Miller, J. S. In
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Structure; Oxford University Press: New York, 1993; p 475. Epstein,
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Symposium #NS-81 Conjugated Polymers and Related Materials: The
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Manriquez, J. M.; Epstein, A. J. Chim. Ind. 1992, 74, 845.
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Mater. 1992, 4, 498. (b) Zhou, P.; Morin, B. G.; Epstein, A. J.;
McLean, R. S.; Miller, J. S. J. Appl. Phys. 1993, 73, 6569.
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[MnTPP]{Ni[S2C2H(CN)]2}, 3. MnIIITPPCl (95.61 mg; 0.136
mmol) and Ag[SbF6] (47.94 mg; 0.140 mmol) were dissolved in
∼7 mL of CH2Cl2 to give green and clear solutions, respectively.
The Ag[SbF6] solution was added dropwise to the rapidly stirred
MnTPPCl solution to produce a black solution containing [MnIII-
TPP][SbF6]. This solution was left to stir for an additional 30 min,
and then it was filtered to remove AgCl. [HNMe3]{Ni[S2C2H-
(CN)]2} (45.32 mg; 0.131 mmol) dissolved in ∼15 mL of CH2Cl2
was slowly diffused into the above filtrate using a three-compart-
ment vessel. After 14 days the vessel was opened and X-ray-quality
crystals and some purple powder were collected. IR (Nujol, νCN):
2210 (m), 2200 (s) cm-1
.
[MnTPP]{Ni[S2C2(CN)2]2}, 4. The above method was used
except that [NBu4]{Ni[S2C2(CN)2]2} was the anion. IR (Nujol,
ν
CN): 2220 (m), 2212 (s) cm-1
.
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Cronin, L. Coord. Chem. ReV. 2002, 227, 93.
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3083.
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J.; Korsakoff, L. J. Org. Chem. 1967, 32, 476.
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Inorganic Chemistry, Vol. 44, No. 21, 2005 7531

Dawe et al.
Table 1. Summary of the Crystallographic Data for [MnTPP]{Ni[S2C2H(CN)]2}, 3, [MnTPP]{Ni[S2C2(CN)2]2}, 4, and
[MnTP′P(OH2)]{Ni[S2C2(CN)2]2}‚EtOH‚H2O, 6
param
formula
formula mass
space group
a, Å
[MnTPP]{Ni[S2C2H(CN)]2}, 3
[MnTPP]{Ni[S2C2(CN)2]2}, 4
[MnT′PP(OH2)]{Ni[S2C2(CN)2]2}‚EtOH‚H2O, 6
C50H30MnN6NiS4
956.69
P1h
10.6560(3)
10.7154(4)
10.8898(2)
97.8288(18)
117.3550(16)
98.5935(15)
1
C52H28MnN8NiS4
1006.71
P1h
10.4769(9)
10.8561(9)
11.2213(9)
99.060(2)
101.452(2)
113.5120(10)
1
C86H102MnN8NiO7S4
1601.65
P1h
14.647(3)
16.688(3)
19.783(4)
90.842(3)
98.920(3)
113.425(3)
2
b, Å
c, Å
R, deg
â, deg
γ, deg
Z
V, Å3
1061.86(5)
0.982
1106.54(16)
0.948
4367.8(15)
0.511
µ, cm-1
F
calcd, g/cm3
1.496
1.511
1.218
R(F)a
wR(F2)b
T, K
0.0411
0.0435
0.0756
0.0768
0.1092
0.1522
150(1)
218(2)
100(2)
λ, Å
0.710 73
0.710 73
0.710 73
2
2
2
a R(F) ) Σ(|Fo| - |Fc|)/Σ|Fo|. b wR(F2) ) [Σ(w(Fo - Fc )2)/Σ(Fo )2]1/2
.
[MnTP′P]{Ni[S2C2(CN)2]2}, 5. The above method for 4 was
used except that MnTP′PCl was utilized and [MnIIITP′P][SbF6] was
prepared in situ. IR (Nujol, νCN): 2208 (s) cm-1. Anal. Calcd (obsd)
for C84H92MnN4NiS4: C, 66.39 (66.42); H, 6.10 (6.15); N, 7.37
(7.51). TGA analysis of 5 reveals that it is thermally stable below
260 °C and decomposes at higher temperature. 5 forms very fine
fibrous crystals that have precluded their structural study. Nonethe-
less, crystals of [MnTP′P(OH2)]{Ni[S2C2(CN)2]2}‚EtOH‚H2O, 6,
composition have been grown from ethanol/water.
their unit cells were determined on a Nonius KappaCCD diffrac-
tometer equipped with Mo KR radiation. The crystallographic data
are summarized in Table 1. Equivalent reflections were merged,
and only those for which Io > 2σ(I) were included in the refinement,
where σ(Fo)2 is the standard deviation based on counting statistics.
Reflections were indexed, integrated, and corrected for Lorentz,
polarization, and absorption effects using DENZO-SMN and
SCALEPAC.27 The structure was solved by a combination of direct
methods and heavy atom methods using SIR 97.28 All of the non-
hydrogen atoms were refined with anisotropic displacement coef-
ficients. Hydrogen atoms were assigned isotropic displacement
coefficients U(H) ) 1.2U(C), and their coordinates were allowed
to ride on their respective carbons using SHELXL97.29
Physical Methods. The thermal properties were studied on a
TA Instruments model 2050 thermogravimetric analyzer (TGA)
equipped with a TA-MS Fison triple filter quadrupole mass
spectrometer, to identify gaseous products with masses less than
300 amu. This instrument is located in a Vacuum Atmospheres
DriLab under argon to protect air- and moisture-sensitive samples.
Samples were placed in an aluminum pan and heated at 20 °C/min
under a continuous 10 mL/min nitrogen flow. The 2-300 K
magnetic susceptibility was determined on a Quantum Design
MPMS-5XL 5 T SQUID (sensitivity ) 10-8 emu or 10-12 emu/
Oe at 1 T) or a PPMS 9T as previously described.20 Due to the
large diamagnetic component of the observed magnetization, all
magnetic measurements were perform in closed nonairtight gelatin
capsules. In addition to correction for the diamagnetic contribution
from the sample holder, core diamagnetic corrections of -430 ×
10-6, -804 × 10-6, -82 × 10-6, and -91 × 10-6 emu/mol based
on summing Pascal’s constants were used for MnTPP, MnTP′P,
{Ni[S2C2H(CN)]2}•-, and {Ni[S2C2(CN)2]2}•-, respectively. Infrared
spectra ((600-4000) ( 1 cm-1) were obtained on a Bruker Tensor
37 FT IR-40 spectrophotometer as potassium bromide pellets.
Elemental analyses were performed by Complete Analysis Labo-
ratories Inc. of Parsippany, NJ.
(20) The B3LYP is a combination of the nonlocal three-parameter exchange
functional (Becke, A. D. J. Chem. Phys. 1993, 98, 5648) and nonlocal
LYP correlation functional (Lee, C.; Yang, W.; Parr, R. G. Phys. ReV.
B 1998, 37, 785).
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724. (b) Clark, T.; Chandrasekhar, J.; Spitznagel, G. W.; Schleyer, R.
v. R. J. Comput. Chem. 1983, 4, 294.
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M. A.; Cheeseman, J. R.; Montgomery, J. A., Jr.; Vreven, T.; Kudin,
K. N.; Burant, J. C.; Millam, J. M.; Iyenger, S. S.; Tomasi, J.; Barone,
V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G.
A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.;
Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai,
H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.;
Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev,
O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P.
Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.;
Zakrewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas,
O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foreman, J. B.;
Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.;
Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.;
Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.;
Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen,
W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian 03, revision
B.02; Gaussian, Inc.: Pittsburgh, PA, 2003.
(23) Kobayahi, A.; Sasaki, Y. Bull. Chem. Soc. Jpn. 1977, 50, 2650.
(24) Glendening, E. D.; Reed, A. E.; Carpenter, A. E.; Weinhold, F. NBO,
version 3.1.
(25) Szabo, A.; Ostlund, N. S. Modern Quantum Chemistry: Introduction
to AdVanced Electronic Structure Theory; Macmillan Publishing Co.,
Inc.: New York, 1982.
(26) Otwinowski, Z.; Minor, W. Methods Enzymol. 1997, 276, 307.
(27) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G.; Giacovazzo,
C.; Guagliardi, A.; Moliteni, A. G. G.; Polidori, G.; Spagna, R. SIR97-A
program for automatic solution and refinement of crystal structure,
release 1.02.
(28) Sheldrick, G. M. SHELX97 (Includes SHELXS97, SHELXL97, CIFT-
AB) Programs for Crystal Structure Analysis, release 97-2; University
of Go¨ttingen: Go¨ttingen, Germany, 1997.
Ab initio calculations were executed using the hybrid B3LYP
exchange and correlation DFT21 with the 6-31++g(d,p) basis set.22
All calculations were done using Gaussian-03.23 The optimized
structures of 1 and 2 were based on the reported crystal structure
for [NEt4]1.24 Trans-substitution of H for CN onto the optimized
structure of 2 yielded 1. Each radical anion was optimized
completely. Mulliken and natural bond orbital (NBO) charge and
spin distributions were calculated.25 NBO spin densities were
determined for both R and â electron populations for each unique
atoms within 2 and 1. The spin density was calculated from the
differences between the R and the â electron populations.26
X-ray Structure Determination. Single crystals of 3, 4, and 6
were grown from their respective solvents via slow diffusion, and
7532 Inorganic Chemistry, Vol. 44, No. 21, 2005

[MnTPP]{Ni[S2C2H(CN)]2}
The final cycle of full-matrix least-squares refinement of 3 was
based on 7757 observed reflections [Io > 2σ(I)] and converged with
unweighted and weighted agreement factors R(F) ) 0.0322 and
wR(F2) ) 0.0710, respectively. The final cycle of full-matrix least-
squares refinement of 4 was based on 8087 observed reflections
[Io > 2σ(I)] and converged with unweighted and weighted agree-
ment factors R(F) ) 0.0435 and wR(F2) ) 0.1092, respectively.
The cations lie on crystallographic inversion centers with Mn at
the center for both 3 and 4.
An extremely thin lavender plate (0.41 × 0.31 × 0.004 mm) of
6 was mounted on a Cryo-loop. The structure was solved by direct
methods. All non-hydrogen atoms were refined anisotropically, and
hydrogen atoms were treated as idealized contributions. The final
cycle of full-matrix least-squares refinement of 6 was based on
7075 observed reflections [Io > 2σ(I)] and converged with
unweighted and weighted agreement factors R(F) ) 0.0756 and
wR(F2) ) 0.1522, respectively. The asymmetric unit consists of
[MnIIITP′P(OH2)]+, two half-{Ni[S2C2(CN)2]2}- anions located on
inversion centers, and one molecule of water and one molecule of
EtOH of solvation.
correlated to poor intrachain antiferromagnetic coupling and
low magnetic ordering temperatures,17 as were subsequently
observed (vide infra). Hence, we targeted the preparation of
[MnTP′P]{Ni[S2C2(CN)2]2} (5) (H2TP′P ) meso-tetrakis[3,5-
di-tert-butyl-4-hydroxyphenyl)porphyrin], which due to the
increased steric constraints arising from the substitution of
the phenyl rings in the 3,5-positions with tert-butyl groups
reduces the dihedral angle between the mean TCNE and
MnN4 planes and stronger antiferromagnetic coupling and
higher magnetic ordering temperatures are expected as
observed for [MnTP′P][TCNE].16
The shift of the νCN absorption of 3 (2210 and 2000 cm-1),
4 (2220 and 2212 cm-1), and 5 (2208 cm-1) with respect to
[HNMe3]{Ni[S2C2H(CN)]2} (νCN ) 2203 cm-1) and [NBu4]-
{Ni[S2C2(CN)2]2} (νCN ) 2206 cm-1) indicates trans-µ-
bonding of the dithiolate radical anion.
Structure. The structures of 3 and 4 were determined by
single-crystal X-ray diffraction. The unit cell and metric
parameters are summarized in Table 1, and the ORTEP
drawings are presented in Figures 1 and 2. In each case the
structures of the [MnIIITPP]+ cations, which lie on crystal-
lographic inversion centers at Mn, are nearly indistinguish-
able and consistent with other D4h [MnIII(por)]+ cations
reported in the literature.8,31,32 The TPP ligand is planar with
Mn-N(pyrrole) bond distances averaging 2.005 Å. The bond
distances and angles of the porphyrin ring are identical within
the limits of the standard deviation for [MnIII(por)]+.
Results and Discussion
Synthesis. Magnetically ordered [MnTPP][TCNE] are
prepared via the electron-transfer reaction of MnIITPP and
TCNE, eq 1. However, neither {Ni[S2C2(CN)2]2}0 nor {Ni-
[S2C2(CN)2]2}0 is stable; hence, eq 1 using these acceptors
is not an option. The sequential oxidation of MnIITPP with
Ag[SbF6] forming [MnIIITPP][SbF6] in situ and the meta-
thesis reaction with either {Ni[S2C2H(CN)]2}•- or {Ni[S2C2(C-
N)2]2}•-, eq 2, forming [MnIIITPP]{Ni[S2C2H(CN)]2} or
[MnIIITPP], respectively, was utilized.
(30) (a) McKee, V.; Ong, C. C.; Rodley, G. A. Inorg. Chem. 1984, 23,
4242. (b) Barkigia, K. M.; Spaulding, L. D.; Fajer, J. Inorg. Chem.
1983, 22, 349.
MnIITPP + TCNE f [MnIIITPP]+[TCNE]•-
MnIITPP + Ag+ f [MnIIITPP]+
(1)
(31) (a) 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. (b) Miller, J. S.; Epstein, A. J. Chem. Commun. 1998, 1319.
(c) Goldberg, I.; Krupitsky, H.; Stein, Z.; Hsiou, Y.; Strouse, C. E.
Supramol. Chem 1995, 4, 203. (d) Krupitsky, H.; Stein, Z.; Goldberg,
I. J. Inclusion Phenom. Mol. Recognit. Chem. 1995, 20, 211. (e)
Goldberg, I. Mol. Cryst. Liq. Cryst. 1996, 278, 767. (f) 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. (g)
Rittenberg, D. K.; Sugiura, K.-i..; Sakata, Y.; Mikami, S.; Epstein, A.
J.; Miller, J. S. AdV. Mater. 2000, 12, 126. (h) Rittenberg, D. K.;
Sugiura, K.-i..; Sakata, Y.; Guzei, I. A.; Rheingold, A. L.; Miller, J.
S. Chem.sEur. J. 1999, 5, 1874. (i) Sugiura, K.-i.; Arif, A.; Rittenberg,
D. K.; Schweizer, J.; O¨ hrstrom, L.; Epstein, A. J.; Miller, J. S. Chem.s
Eur. J. 1997, 3, 138. (j) Brandon, E. J.; Sugiura, K.-i.; Arif, A. M.;
Liable-Sands, A.; Rheingold, A. L.; Miller, J. S. Mol. Cryst., Liq. Cryst.
1997, 305, 269. (k) Brandon, E. J.; Burkhart, B. M.; Rogers, R. D.;
Miller, J. S. Chem.sEur. J. 1998, 4, 1938. (l) Brandon, E. J.; Arif, A.
M.; Burkhart, B. M.; Miller, J. S. Inorg. Chem. 1998, 37, 2792. (m)
Brandon, E. J.; Arif, A. M.; Miller, J. S.; Sugiura, K.-i.; Burkhart, B.
M. Cryst. Eng. 1998, 1, 97. (n) Sugiura, K.-i.; Mikami, S.; Tanaka,
T.; Sawada, M.; Manson, J. L.; Miller, J. S.; Sakata, Y. Chem. Lett.
1997, 1071. (o) Day, V. W.; Sults, B. R.; Tasset, E. L.; Marianelli, R.
S.; Boucher, L. J. Inorg. Nucl. Chem. Lett. 1975, 11, 505. (p) Cheng,
B.; Cukiernik, F.; Fries, P.; Marchon, J.-C.; Scheidt, W. R. Inorg.
Chem. 1995, 34, 4627. (q) Guildard, R.; Perie, K.; Barbe, J.-M.; Nurco,
D. J.; Smith, K. M.; Caemelbecke, E. V.; Kadish, K. M. Inorg. Chem.
1998, 37, 973. (r) Landrum, J. T.; Hatano, K.; Scheidt, W. R.; Reed,
C. A. J. Am. Chem. Soc. 1980, 102, 6729. (s) Hill, C. L.; Williamson,
M. M. Inorg. Chem. 1985, 24, 3024. (t) Fleischer, E. B. Acc. Chem
Res. 1970, 3, 105. (u) Scheidt, W. R.; Reed, C. A. Chem. ReV. 1981,
81, 543. (v) Turner, P.; Gunter, M. J.; Hambley, T. W.; White, A. H.;
Skelton, B. W. Inorg. Chem. 1992, 31, 2297.
(2a)
[MnIIITPP]+ + {Ni[S2C2(CN)2]2}•-
f
[MnIIITPP]{Ni[S2C2(CN)2]2} (2b)
Since {Ni[S2C2H(CN)]2}•- [E1/2° ) -0.31 V vs SCE]10
and {Ni[S2C2(CN)2]2}•- [E1/2° ) 0.23 V]10 are easily reduced
to the dianion, care was extended to minimize their forma-
tion, but they are observed. X-ray-quality crystals were grown
from solutions of CH2Cl2 by slow diffusion. Unexpectedly,
neither [MnIIITPP]{Ni[S2C2H(CN)2]} nor [MnIIITPP]{Ni-
[S2C2(CN)2]2} is solvated as observed for all previously
characterized TCNE electron-transfer salts with MnTPP or
substituted MnTPP’s3a as well as so many other MTPPs that
they have been called sponges.30 This eliminates differences
in data arising from differing solvent contents.
Structural studies on 3 and 4 revealed that the µ-radical
anion acceptor is nearly perpendicular with respect to the
MnN4 porphyrin plane (vide infra). The motif has been
(29) (a) Goldberg, I.; Krupitsky, H.; Stein, Z.; Hsiou, Y.; Strouse, C. E.
Supramol. Chem 1995, 4, 203. (b) Krupitsky, H.; Stein, Z.; Goldberg,
I. J. Inclusion Phenom. Mol. Recognit. Chem. 1995, 20, 211. (c)
Goldberg, I. Mol. Cryst. Liq. Cryst. 1996, 278, 767. (d) 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. Byrn,
M. P.; Curtis, C. J.; Hsiou, Y.; Khan, S. I.; Sawin, P. A.; Terzis, A.;
Strouse, C. E. In ComprehensiVe Supramolecular Chemistry; Atwood,
J. L., Davies, J. E. D., MacNicol, D. D., Vogtle, F., Eds.; 1996; Vol.
6, p 715.
(32) Zurcher, S.; Gramlich, V.; Arx, D. v.; Tongi, A. Inorg. Chem. 1998,
37, 4015. Day, M. W.; Qin, J.; Yang, C. Acta Crystallogr. 1998, C54,
1413. Hobi, M.; Zurcher, S.; Gramlich, V.; Burckhardt, U.; Mensing,
C.; Spahr, M.; Tongi, A. Organometellics 1996, 15, 5342. Brunn, K.;
Endes, H.; Weiss, J. Z. Naturforsh. 1987, 42b, 1222. Ramakrishna,
B. L.; Manoharan, P. T. Inorg. Chem. 1983, 22, 2213.
Inorganic Chemistry, Vol. 44, No. 21, 2005 7533

Dawe et al.
Figure 1. ORTEP atom-labeling diagram of [MnTPP]{Ni[S2C2H(CN)]2}, 3, using 30% thermal ellipsoids.
Å) for a member of the [MnTPP][TCNE]‚x(solvates) family34
as both 1 and 2 are much larger than [TCNE]•-. The larger
Mn‚‚‚Mn separations enable adjacent chains to interdigitate
(Figures 3a and 4a) not enabling the solvent to be occluded.
The out-of-registry interchain separations are 8.14 and 8.40
Å for 3 and 4, respectively. This is at variance with all other
[MTPPs][TCNE] that occlude solvents and are termed
sponges.30 The longer intra-N‚‚‚N separation of 11 Å for 3
and 4 vs ∼5.9 Å for [TCNE]•- increases the intrachain Mn‚
‚‚Mn separation by 45% to ∼14.25 Å from ∼9.8 Å enabling
interdigitation to occur. [TCNQF4]•- with its N‚‚‚N separa-
tion of ∼9.5 Å (Mn‚‚‚Mn separation ) 12.68 Å), like
[TCNE]•-, is also solvated.35 This, it appears that Mn‚‚‚Mn
separations ∼14 Å (and N‚‚‚N separations ∼10 Å) are
needed for interdigitation to occur for the MnTPP family of
1-D coordination polymers.
Attempts to grow crystals of 5 suitable for a single-crystal
X-ray structural analyses were unsuccessful due to formation
of only fibrous needle crystals. Due to the stability of the
2•-, crystallization from ethanol/water was successful. How-
ever, the sought 1-D coordination polymer motif was not
observed as the no terminal nitrogens {Ni[S2C2(CN)2]2}•-
bond to a Mn(III). Each Mn(III) is five coordinate with four
N atoms and the axial water, and the unit cell has an ethanol
and additional water molecule. The coordinated water and
lattice water are H-bonded (O‚‚‚O ) 2.82 Å), and the
molecule of EtOH is H-bonded to N5 in one of the Ni
complexes. The Mn‚‚‚S is 3.4 Å, which is less than the sum
of the van der Waal radii indicative of an interaction. Hence,
the composition is [MnTP′P(OH2)]{Ni[S2C2(CN)2]2}‚EtOH‚
Figure 2. ORTEP atom-labeling diagram of [MnTPP]{Ni[S2C2(CN)2]2},
4, complexes using 30% thermal ellipsoids.
110 and 233 are planar with intramolecular distances and
angles comparable to that reported for the isolated ligands.
1 and 2 are uniformly trans-µ-N-σ-bound to two MnIII’s
forming parallel 1-D‚‚‚D+A•-D+A•-‚‚‚ [D ) MnTPP; A )
1 (Figure 3) or 2 (Figure 4)] chains. Chains I-II and I-III
are out-of-registry, and chains II-II and I-IV are in-
registry. The key inter- and intrachain interaction can be
found in Figures 3 and 4 and summarized in Table 2.
The acceptor N-Mn distances are 2.339(16) and 2.394-
(3) Å for 3 and 4, respectively, which are on the high side
but comparable to that observed for [MnTPP][TCNE]‚
x(solvates).32a The MnNC angles are 139.9 ( 1.5° while the
dihedral angle between the mean MnN4 and the mean
acceptor planes range from 79.5 to 85.2° for 3 and 4,
respectively. These former values are typical of related
compounds,32 while the latter are on the high side indicative
(33) Rittenberg, D. K.; Arif, A. M.; Miller, J. S. J. Chem. Soc., Dalton
Trans. 2000, 3939.
(34) Johnson, M. T.; Arif, A. M.; J. S. Miller, J. S. Eur. J. Inorg. Chem.
2000, 1781.
(35) Values less than the calculated spin only value of 2.45 µB are attributed
to weighing errors due to errors in molecular weight due to the specific
degree of solvation and subtraction of the ferromagnetic impurity.
2
of poorer pz-dz overlap and reduced coupling leading to
lower Tc’s.17
The intrachain Mn‚‚‚Mn separations range from 14.20 to
14.33 Å for 3 and 4, respectively, which are expectedly
longer (>2 Å) than even the longest one observed (10.39
7534 Inorganic Chemistry, Vol. 44, No. 21, 2005

[MnTPP]{Ni[S2C2H(CN)]2}
Figure 3. View down the a-axis normal to the parallel chains showing the interchain interactions among chains I-IV (a). View parallel to out-of-registry
chains I-II (b) and I-III (c) and in-registry chains I-IV (s) and II-III (e) for [MnTPP]{Ni[S2C2H(CN)]2}, 3.
H2O, 6. The unit cell and metric parameters are summarized
in Table 1, and the ORTEP atom labeling drawing is
presented in Figure 5. The structures of the C4v [MnIIITPP-
(OH2)]+ cation are nearly indistinguishable and consistent
with related five coordinate [MnIII(por)]+ cations reported
in the literature.
Magnetic Data. The 2-300 K corrected molar magnetic
susceptibility, ø, was measured for 3-5. The 300 K values
Inorganic Chemistry, Vol. 44, No. 21, 2005 7535

Dawe et al.
Figure 4. View down the a-axis normal to the parallel chains showing the interchain interactions among chains I-IV (a). View parallel to out-of-registry
chains I-II (b) and I-III (c) and in-registry chains I-IV (d) and II-III (e) for [MnTPP]{Ni[S2C2(CN)2]2}, 4.
7536 Inorganic Chemistry, Vol. 44, No. 21, 2005

[MnTPP]{Ni[S2C2H(CN)]2}
Table 2. Summary of Key Bond Distances and Separations for
[MnTPP]{Ni[S2C2H(CN)]2}, 3, and [MnTPP]{Ni[S2C2(CN)2]2}, 4
moment remains relatively constant with decreasing tem-
perature until approximately 50-100 K (Figure 6). Above
20 K, øT(T) can be fit to the Curie-Weiss expression, ø
1/(T - Θ), with Θ ) -1.4 and -0.57 K for 3 and 4,
respectively, indicating weak antiferromagnetic coupling.
Above 190 K for 5, øT(T) changes slope; if data could be
taken to a higher temperature, øT(T) could be fit with Θ <
0 K. øT(T), however, is linear between 80 and 190 K and
can be fit to the Curie-Weiss expression with effective Θ,
Θ′, of 49 K (Figure 6).
The [MnTPP][TCNE]‚xS family of compounds has sig-
nificant antiferromagnetic intrachain interactions and order
as ferrimagnets. Minima in the øT(T), Tmin, are observed at
22 and 8 K for 3 and 4, respectively, that indicate dominant
antiferromagnetic coupling.23 Typically, the øT(T) data above
∼50 K can be fit to the Seiden expression36 for a uniform
isolated 1-D chain comprised of alternating quantum (S )
1/2) and classical (g ) 2; S ) 2) spin sites (H ) -2JSi‚Sj).
However, below ∼50 K, the onset of long-range interchain
coupling occurs and no appropriate magnetic model exists.
The 1-D intrachain coupling, Jintra, of 3-5 was determined
from modeling øT(T) by the Seiden expression with J/kB )
-8.0 K (J ) -5.6 cm-1) for 3, -3.0 K (-2.1 cm-1) for 4,
and -122 K (-85 cm-1) for 5 (Figure 6). These observed
negative Jintra/kB values are indicative of antiferromagnetic
coupling. The Seiden model is not valid below ∼50 K due
to increased 3-D spin correlations or for systems in which
the intrachain coupling is weak, likely due to next nearest
neighbor interactions. For 5 the Seiden model was modified
to include Θ, to account for the interchain interactions, and
Θ ) -8 K (-5.6 cm-1) indicating antiferromagnetic
interchain couplings, which are much weaker than the
intrachain interactions, i.e., -122 K.
[MnTPP]{Ni-
[MnTPP]{Ni-
param
[S2C2H(CN)]2}, 3 [S2C2(CN)2]2}, 4
MnNCN, Å
MnNC, deg
MnN4-TCNE dihedral angle, deg
MnNpor, Å
2.3390(16)
139.39(15)
79.5
2.0072(15)
2.0140(14)
180.00(7)
14.200
2.394(3)
141.41(3)
85.2
1.996(2)
2.002(2)
180.00(12)
14.332
NCN-Mn-NCN, deg
Mn‚‚‚Mn intrachain, Å
Mn‚‚‚Mn interchain,a Å
10.656b
10.715b
10.890b
11.202c
13.206b
13.937c
8.136b
10.476b
10.857b
11.221b
11.698c
13.332b
13.748c
8.404b
interchain separatn, Å
9.435b
9.311b
10.969c
13.791c
11.509c
13.491c
a <15 Å. b Out-of-registry. c In-registry.
Figure 5. ORTEP atom-labeling diagram of [MnTP′P]2Ni[S2C2(CN)2]2},
6, depicted without solvent molecules and with symmetry-completed Ni
complexes using 30% thermal ellipsoids.
Isothermal field-dependent magnetization, M(H), experi-
ments reveal magnetizations at 50 kOe and at 2 K of 10 700
(3), 15 000 (4), and 11 700 (5) emu Oe/mol. For an
antiferromagnetic Stot ) 2 - 1/2 ) 3/2 system, the expected
saturation magnetization, Ms, is 16 755 emu Oe/mol, and for
a ferromagnetic Stot ) 2 + 1/2 ) 5/2 system, Ms is expected
to be 27 925 emu Oe/mol. The magnitude of the magnetiza-
of øT for 3-5 are 2.55, 3.28, and 2.86 emuK/mol, respec-
tively, averaging 2.90 emu K/mol, in accord with the
expected value for and S ) 2 and S ) 1/2 spins of 3.38 emu
K/mol, with antiferromagnetic coupling.36 For 3 and 4, the
Figure 6. ø-1(T) and øT(T) for 3 (b, ×), 4 (b, ×), and 5 (b, ×). The inset shows the fit of øT(T) to the Seiden model (see text) for 5.
Inorganic Chemistry, Vol. 44, No. 21, 2005 7537

Dawe et al.
Figure 7. Zero field (ZFC) and field cooled (FC) M(T) for 5.
Figure 8. 2 K M(H) showing hysteretic behavior for 5.
tion at 5 T (and even 9 T of 13 300 emu Oe/mol for 5) is
lower than expected for an antiferromagnetically coupled Stot
) 2 - 1/2 system; however, on the basis of the slope of the
M(H) curves, saturation was not evident. Thus, these
materials are ferrimagnets.7b
Magnetic ordering temperatures, Tc, were determined by
the peak in the in-phase susceptibility at 10 Hz, ø′(T), and
are from 5.5, 2.3, and 8.0 K for 3-5, respectively. Both the
in-phase and out-of-phase ac susceptibilities are frequency
dependent. Frequency (ω) dependencies of the ac suscepti-
bility, φ ) ∆Tf/(Tf ∆(log ω), and are 0.015, 0.031, and 0.19
for 3-5, respectively. The values for 3 and 4 are consistent
with typical spin glasses26 as reported for related materials.4a,20
The higher value of 0.19 for 5 is characteristic of greater
disorder, presumable due to the tert-butyl groups, as reported
for [MnTP′P][TCNE]‚2PhMe that has φ ) 0.18.16 Very small
φ values (<0.001) are typically noted for ferromagnets and
weak ferromagnets. However, disordered spins systems
display φ values which typically range from 0.01 to 0.1 such
as found in the alloys of PdMn, φ ) 0.013, and NiMn, φ )
0.018, and the superparamagnet R-(Ho2O3)(B2O3), φ )
0.28.26
Zero-field-cooled and field-cooled magnetic measurement
were taken below 35 K at 5 Oe field for 5 (Figure 7). These
data reveals a bifurcation temperature, Tb, at 4.8 K in accord
with magnetic ordering.
Magnetic ordering is further evidenced by the presence
of hysteresis loop that is observed for 3 and 5. 3 exhibits a
coercive field, Hcr, of 550 Oe and remanent magnetization
of 7800 emu Oe/mol at 2 K. Due to the higher Tc, 5 has a
Hcr of 17 700 Oe and remanent magnetization of 7250 emu
Oe/mol at 2 K and 17 Oe and 850 emu Oe/mol at 5 K,
respectively (Figures 8 and 9). Albeit large, the 2 K 17 700
(36) Seiden, J. J. Phys. Lett. 1983, 44, L947.
7538 Inorganic Chemistry, Vol. 44, No. 21, 2005

[MnTPP]{Ni[S2C2H(CN)]2}
cooling 5 goes from being a soft magnet to being a very
hard magnet. The coercivity decreases linearly with increas-
ing temperature, as observed for [MnTBrPP][TCNE] (MnT-
BrPP ) (meso-tetrakis(4-bromophenyl)porphinato)manganese-
(III).9
In contrast, 4 does not exhibits either a Hcr or Mrem that is
atypical for [Mn(porphyrin)][TCNE] systems17 due to its low
Tc with respect to the 2 K at which the measurements are
made.
A relationship between structure and magnetic properties
continues to be elusive. The data herein and that previously
reported3a,16 demonstrate a trend toward higher Θ′ being
associated with smaller dihedral angle formed from the
[TCNE]•- and MnN4 mean planes. These angles are influ-
enced by the size of the solvent molecule or porphyrin ring
substituents.
MO Calculations. Mulliken and NBO charge and spin
density calculations were performed using the B3LYP DFT
and the 6-31++g(d,p) basis set for both {Ni[S2C2H(CN)]2}•-
(1) and {Ni[S2C2(CN)2]2}•- (2) (Table S1 and S2).
The Mulliken and NBO charge distributions for 1 and 2
differ significantly (Table S1 and S2). The Mulliken charge
distribution reveals the majority of the positive charge for 1
resides on C1 and H, 0.20 and 0.21, respectively. However,
for 2 the majority of the positive charge is on C1, 0.53, with
Ni having 0.16 (vs 0.05 for 1). This is at variance to the
NBO charge distributions where the majority of the positive
charge for both 1 and 2 reside on Ni (0.49 each). In addition
the Mulliken charge distribution for 1 reveals a -0.11 charge
difference between S1 and S2 and a -0.07 difference
between C1 and C3, whereas the NBO charge distribution
for 1 shows no difference between S1 and S2 and only a
-0.01 difference between C1 and C3. Thus, the trans-
substitution of H for CN caused a significant change in the
Mulliken charge distribution but little to no effect in the NBO
charge distribution.
The NBO spin distributions for 1 and 2 (Tables S1 and
S2) reveal that the majority of the positive spin density/atom
resides on Ni with values of 0.22 and 0.23, respectively. In
addition the NBO spin distribution for 1 reveals a 0.06 spin
density difference between S1 and S2 and a 0.03 difference
between C1 and C3; similar differences are observed in the
Mulliken spin distribution. In general the presence of H in
1 allows a small potion of the positive spin density present
on Ni and S to be pulled further out onto the molecule, a
possible explanation for why 3 has a higher Tc than 4.
Acknowledgment. The authors gratefully acknowledge
discussions with Israel Goldberg (Tel Aviv University) and
support in part from the National Science Foundation Grant
Nos. CHE9730948, CHE 0110685, and CHE-9002690.
Supporting Information Available: Calculated NBO and
Mulliken charge and spin (R and â) distributions as well as total
electronpopulationsfor{Ni[S2C2H(CN)]2}•-,1,and{Ni[S2C2(CN)2]2}•-,
2. This material is available free of charge via the Internet at http://
pubs.acs.org. X-ray CIF files for [MnTPP]{Ni[S2C2H(CN)]2}, 3,
[MnTPP]{Ni[S2C2(CN)2]2}, 4, and 6 have been deposited with the
Cambridge Crystallographic Data Center, reference nos. CCDC-
275193, CCDC 275194, and CCDC 275195, respectively.
Figure 9. Real, ø′(T), and imaginary, ø′′(T), ac susceptibilities for 5. The
lines are guides.
Oe coercivity is lower in value than that observed for the
[MnTPP][TCNE] family of molecule-based magnets, which
frequently have coercivities exceeding 25 000 Oe.9 The 5 K
Hcr values for the [MnTPP][TCNE] family of ferrimagnets
are much smaller than that observed at 2 K and typical in
the range of several hundred Oe. 5, however, is atypical due
to its 5 K Hcr 1 order of magnitude lower. Hence, upon
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Inorganic Chemistry, Vol. 44, No. 21, 2005 7539