Monoanionic {Mn(NO)}5 and dianionic {Mn(NO)}6 thiolatonitrosylmanganese complexes: [(NO)Mn(L)2]- and [(NO)Mn(L)2]2- (LH2 = 1,2-Benzenedithiol and toluene-3,4-dithiol)

Article abstract of DOI:10.1021/ic801553s

The reaction of MnBr₂ and [PPN]₂[S,S-C ₆H₃-R] (1:2 molar ratio) in THF yielded [(THF)Mn(S,S-C₆H₃-R)₂]^- [R = H (1a), Me (1b); THF = tetrahydrofuran]. Formation of the dimeric [Mn(S,S-C ₆H₃-R)₂]₂^2- [R = H (2a), Me (2b)] was presumed to compensate for the electron-deficient Mn^III core via two thiolate bridges upon dissolution of complexes 1a and 1b in CH ₂Cl₂. Complex 2a displays antiferromagnetic coupling interaction between two Mn^III centers (J = -52 cm^-1), with the effective magnetic moment (μ_eff) increasing from 0.85 μ_B at 2.0 K to 4.86 μ_B at 300 K. The dianionic manganese(II) thiolate complexes [Mn(S,S-C₆H₃-R) ₂]^2- [R = H (3a), Me (3b)] were isolated upon the addition of [BH₄]^- into complexes 1a and 1b or complexes 2a and 2b, respectively. The anionic mononuclear {Mn(NO)}⁵ thiolatonitrosylmanganese complexes [(NO)Mn(S,S-C₆H ₃-R)₂]^- [R = H (4a), Me (4b)] were obtained from the reaction of NO(g) with the anionic complexes 1a and 1b, respectively, and the subsequent reduction of complexes 4a and 4b yielded the mononuclear (Mn(NO)}⁶ [(NO)Mn(S,S-C₆H₃-R)₂] ^2- [R = H (5a), Me (5b)]. X-ray structural data, magnetic susceptibility measurement, and magnetic fitting results imply that the electronic structure of complex 4a is best described as a resonance hybrid of [(L)(L)Mn^IIINO^?)]^- and [(L)(L ^?)Mn^III(NO^-)]^- (L = 1,2-benzenedithiolate) electronic arrangements in a square-pyramidal ligand field. The lower IR v_NO stretching frequency of complex 5a, compared to that of complex 4a (shifting from 1729 cm^-1 in 4a to 1651 cm ^-1 in 5a), supports that one-electron reduction occurs in the {(L)(L^?)Mn^III} core upon reduction of complex 4a.

Full text of DOI:10.1021/ic801553s

Inorg. Chem. 2008, 47, 11435-11443
Monoanionic {Mn(NO)}5 and Dianionic {Mn(NO)}6
Thiolatonitrosylmanganese Complexes: [(NO)Mn(L)2]- and
[(NO)Mn(L)2]2- (LH2 ) 1,2-Benzenedithiol and Toluene-3,4-dithiol)
Chia-Huei Lin,† Chien-Ge Chen,† Ming-Li Tsai,† Gene-Hsiang Lee,‡ and Wen-Feng Liaw*,†
Department of Chemistry, National Tsing Hua UniVersity, Hsinchu 30013, Taiwan, and
Instrumentation Center, National Taiwan UniVersity, Taipei, Taiwan
Received August 14, 2008
The reaction of MnBr2 and [PPN]2[S,S-C6H3-R] (1:2 molar ratio) in THF yielded [(THF)Mn(S,S-C6H3-R)2]- [R ) H
(1a), Me (1b); THF ) tetrahydrofuran]. Formation of the dimeric [Mn(S,S-C6H3-R)2]22- [R ) H (2a), Me (2b)] was
presumed to compensate for the electron-deficient MnIII core via two thiolate bridges upon dissolution of complexes
1a and 1b in CH2Cl2. Complex 2a displays antiferromagnetic coupling interaction between two MnIII centers (J )
-52 cm-1), with the effective magnetic moment (µeff) increasing from 0.85 µB at 2.0 K to 4.86 µB at 300 K. The
dianionic manganese(II) thiolate complexes [Mn(S,S-C6H3-R)2]2- [R ) H (3a), Me (3b)] were isolated upon the
addition of [BH4]- into complexes 1a and 1b or complexes 2a and 2b, respectively. The anionic mononuclear
{Mn(NO)}5 thiolatonitrosylmanganese complexes [(NO)Mn(S,S-C6H3-R)2]- [R ) H (4a), Me (4b)] were obtained
from the reaction of NO(g) with the anionic complexes 1a and 1b, respectively, and the subsequent reduction of
complexes 4a and 4b yielded the mononuclear {Mn(NO)}6 [(NO)Mn(S,S-C6H3-R)2]2- [R ) H (5a), Me (5b)]. X-ray
structural data, magnetic susceptibility measurement, and magnetic fitting results imply that the electronic structure
of complex 4a is best described as a resonance hybrid of [(L)(L)MnIII(NO•)]- and [(L)(L•)MnIII(NO-)]- (L ) 1,2-
benzenedithiolate) electronic arrangements in a square-pyramidal ligand field. The lower IR vNO stretching frequency
of complex 5a, compared to that of complex 4a (shifting from 1729 cm-1 in 4a to 1651 cm-1 in 5a), supports that
one-electron reduction occurs in the {(L)(L•)MnIII} core upon reduction of complex 4a.
Introduction
to form N2O and metal nitrite via a metal nitrosyl intermedi-
ate;4 and (v) interactions of NO and heme/nonheme proteins
resulting in physiologically relevant M-NO bonds.5
Because of the “noninnocent” character of both NO (acting
as NO+, NO-, and a NO• radical)6 and a 1,2-benzenedithi-
olate ligand,7-11 the determination of formal oxidation states
of a transition metal and NO in the 1,2-benzenedithi-
olatometal nitrosyl complexes may rely on an understanding
of what low-lying excited states are present and how this
Transition-metal nitrosyl complexes have attracted con-
siderable interest stimulated by (i) the versatile bonding
properties between metal and NO;1 (ii) the elucidation of
the electronic structure of transition-metal nitrosyls having
intrigued inorganic chemists;2 (iii) the metal nitrosyl com-
plexes being employed to serve as a nitric oxide delivery
reagent to biological targets;3 (iv) the ability of certain
transition-metal complexes promoting NO disproportionation
* To whom correspondence should be addressed. E-mail: wfliaw@
mx.nthu.edu.tw.
(3) (a) Cheng, L.; Richter-Addo, G. B. Binding and Activation of Nitric
Oxide by Metalloporphyrins and Heme. In The Porphyrin Handbook;
Guilard, R., Smith, L., Kadish, K. M., Eds.; Academic Press: New
York, 2000; Vol. 4, Chapter 33. (b) Afshar, R. K.; Patra, A. K.;
Mascharak, P. K. J. Inorg. Biochem. 2005, 99, 1458.
†
National Tsing Hua University.
National Taiwan University.
‡
(1) (a) Ford, P. C.; Bourassa, J.; Lee, K. B.; Lorkovic, I.; Boggs, S.; Kudo,
S.; Laverman, L. Coord. Chem. ReV. 1998, 171, 185. (b) Ford, P. C.;
Lorkovic, I. M. Chem. ReV. 2002, 102, 993. (c) Butler, A. R.; Megson,
I. L. Chem. ReV. 2002, 102, 1155.
(4) Averill, B. A. Chem. ReV. 1996, 96, 2951.
(5) Richter-Addo, G. B.; Legzdins, P. Metal Nitrosyls; Oxford University:
New York, 1992.
(2) (a) Hayton, T. W.; Legzdins, P.; Sharp, W. B. Chem. ReV. 2002, 102,
935. (b) Hsu, I.-J.; Hsieh, C.-H.; Ke, S.-C.; Chiang, K.-A.; Lee, J.-
M.; Chen, J.-M.; Jang, L.-Y.; Lee, G.-H.; Wang, Y.; Liaw, W.-F.
J. Am. Chem. Soc. 2007, 129, 1151.
(6) (a) Pierpont, C. G.; Buchanan, R. M. Coord. Chem. ReV. 1981, 38,
45. (b) Attia, A. S.; Pierpont, C. G. Inorg. Chem. 1995, 34, 1172. (c)
Wang, P. G.; Xian, M.; Tang, X.; Wu, X.; Wen, Z.; Cai, T.; Janczuk,
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10.1021/ic801553s CCC: $40.75  2008 American Chemical Society
Inorganic Chemistry, Vol. 47, No. 23, 2008 11435
Published on Web 11/07/2008

Lin et al.
Scheme 1
affects the electronic spectroscopy,11 although the metal-NO
unit has so far been generally designated by {M(NO)x}n,
where n ) total number of electrons in the valence orbitals
of the metal ion and π* orbitals of NO, known as
Enemark-Feltham notation.8,12 Recently, some interesting
compounds of NO binding metal centers such as M-NO+/
M-NO-/M-NO• have been reported.9-11 Though Fe-N-O
is almost linear [Fe-N-O ) 174.3(4)°] and the Fe-N bond
length is as low as 1.670(4) Å, Lippard and co-workers7
concluded on the basis of electron paramagnetic resonance
(EPR), Mo¨ssbauer spectroscopy, SQUID susceptometry, and
normal-coordinate analysis that the structure of [(NO)Fe(TC-
5,5)] (TC-5,5 ) tropocoronand) is a trigonal bipyramid with
a low-spin-state {FeIII(NO-)} electronic structure.9 On the
basis of Mo¨ssbauer spectroscopy and EPR measurements,
Wieghardt and co-workers concluded that the electronic
structure of [Fe(H2O)5(NO)]2+ is best described as
[FeIII(H2O)5(NO-)]2+ with FeIII antiferromagnetically coupled
to NO- (S ) 1), yielding the observed spin quartet ground
state (S ) 3/2).10 Interestingly, the experimental and theoreti-
cal studies conducted by Wanner et al. show that
[(NC)5Fe(NO)]3- contains delocalized oxidation levels of the
Figure 1. ORTEP drawing of the anionic part ([(THF)Mn(S,S-C6H4)2]-)
of complex 1a with thermal ellipsoids drawn at the 50% probability level.
Selected bond distances (Å) and angles (deg): Mn-O1 2.250(3), Mn-S1
2.3035(12), Mn-S2 2.3052(12), Mn-S3 2.2954(12), Mn-S4 2.3092(12);
O1-Mn-S3 99.07(9), S3-Mn-S1 87.57(4), S3-Mn-S2 158.91(5),
O1-Mn-S4 93.92(8), S1-Mn-S4 171.17(5), O1-Mn-S2 101.94(9),
O1-Mn-S1 94.43(8).
benzenedithiolate serving as good σ- and π-donating coli-
gands. By application of nitrosylation of [(THF)Mn(S,S-
C6H3-R)2]- [R ) H (1a), Me (1b); THF ) tetrahydrofuran],
the anionic {Mn(NO)}5 [(NO)Mn(S,S-C6H3-R)2]- [R ) H
(4a), Me (4b)] complexes were prepared. Because of the
noninnocent nature of the ligands, three resonate forms of
{Mn(NO)}5 [(NO)Mn(S,S-C6H3-R)2]- can be described as
in Scheme 1. The dianionic, mononuclear {Mn(NO)}6
[(NO)Mn(S,S-C6H3-R)2]2- [R ) H (5a), Me (5b)] complexes
were produced upon the reduction of complexes 4a and 4b
by [S,NH2-C6H4]-, respectively. Oxygen oxidation of the
{Mn(NO)}6 complexes 5a and 5b leads to the formation of
complexes 4a and 4b and the major product [Mn(S,S-C6H3-
R)3]2- [R ) H (6a), Me (6b)], respectively.15
metal and ligand, namely,
a resonance hybrid of
[(NC)5FeII(NO· )]3- and [(NC)5FeI(NO+)]3-.11
In spite of a large number of mononuclear {Mn(NO)}6
and {Mn(NO)}7 manganese nitrosyl complexes known,2b,13
no examples of mononuclear {Mn(NO)}5 thiolatonitrosyl-
manganese complexes are reported. The present investigation
was therefore initiated to uncover the electronic structure
and reactivity of the unexplored {Mn(NO)}5 thiolatonitrosyl-
manganese complexes by introducing the redox-active 1,2-
Results and Discussion
(7) (a) Franz, K. J.; Lippard, S. J. J. Am. Chem. Soc. 1998, 120, 9034.
(b) Brown, C. A.; Pavlosky, M. A.; Westre, T. E.; Zhang, Y.; Hedman,
B.; Hodgson, K. O.; Solomon, E. I. J. Am. Chem. Soc. 1995, 117,
715. (c) Mingos, D. M. P.; Sherman, D. J. AdV. Inorg. Chem. 1989,
34, 293.
(8) Enemark, J. H.; Feltham, R. D. Coord. Chem. ReV. 1974, 13, 339.
(9) Franz, K. J.; Lippard, S. J. J. Am. Chem. Soc. 1999, 121, 10504.
(10) (a) Wanat, A.; Schneppensieper, T.; Stochel, G.; van Eldik, R.; Bill,
E.; Wieghardt, K. Inorg. Chem. 2002, 41, 4. (b) Ray, K.; Weyher-
mu¨ller, T.; Goossens, A.; Craje´, M. W. J.; Wieghardt, K. Inorg. Chem.
2003, 42, 4082. (c) Ghosh, P.; Stobie, K.; Bill, E.; Bothe, E.;
Weyhermu¨ller, T.; Ward, M. D.; McCleverty, J. A.; Wieghardt, K.
Inorg. Chem. 2007, 46, 522. (d) Herebian, D.; Bothe, E.; Bill, E.;
Weyhermuller, T.; Wieghardt, K. J. Am. Chem. Soc. 2001, 123, 10012.
(e) Chaudhuri, P.; Verani, C. N.; Bill, E.; Bothe, E.; Weyhermuller,
T.; Wieghardt, K. J. Am. Chem. Soc. 2001, 123, 2213.
Synthetic and Characterization Aspects: Interconver-
sion among [(THF)Mn(L)2]-, [Mn(L)2]22-, and [Mn(L)2]2-
(THF ) tetrahydrofuran; L ) 1,2-Benzenedithiolate and
Toluene-3,4-dithiolate). The anionic mononuclear manganese
thiolate complexes [(THF)Mn(S,S-C6H3-R)2]- [R ) H (1a),
Me (1b); THF ) tetrahydrofuran] containing [S,S-C6H3-R]2-
and [C4H8O] ligands bound to manganese in a bidentate and
a monodentate manner, respectively, were obtained when a
MeOH solution of 2 equiv of [Na]2[S,S-C6H3-R] and MnBr2
was added to a THF solution of [PPN][Cl] (or [Et4N][Br]).
Presumably, the role of a THF ligand coordinated to a MnIII
center in complex 1a is to compensate for the electron
deficiency of the MnIII center as well as to stabilize the MnIII
(11) Wanner, M.; Scheiring, T.; Kaim, W.; Slep, L. D.; Baraldo, L. M.;
Olabe, J. A.; Zalis, S.; Baerends, E. J. Inorg. Chem. 2001, 40, 5704.
(12) (a) Enemark, J. H.; Feltham, R. D. Proc. Natl. Acad. Sci. U.S.A. 1972,
69, 3534. (b) Leverman, L. E.; Wanat, A.; Oszajca, J.; Stochel, G.;
Ford, P. C.; van Eldik, R. J. Am. Chem. Soc. 2001, 123, 285. (c) Gray,
H. B.; Bernal, I.; Billig, E. J. Am. Chem. Soc. 1962, 84, 3404.
(13) (a) Scheidt, W. R.; Hatano, K.; Rupprecht, G. A.; Piciulo, P. L. Inorg.
Chem. 1979, 18, 292. (b) Ghosh, K.; Eroy-Reveles, A. A.; Avila, B.;
Holman, T. R.; Olmstead, M. M.; Mascharak, P. K. Inorg. Chem. 2004,
43, 2988. (c) Zahran, Z. N.; Shaw, M. J.; Khan, M. A.; Richter-Addo,
G. B. Inorg. Chem. 2006, 45, 2661.
(15) (a) Lee, C.-M.; Hsieh, C.-H.; Dutta, A.; Lee, G.-H.; Liaw, W.-F. J. Am.
Chem. Soc. 2003, 125, 11492. (b) Lee, C.-M.; Chen, C.-H.; Chen,
H.-W.; Hsu, J.-L.; Lee, G.-H.; Liaw, W.-F. Inorg. Chem. 2005, 44,
6670.
(16) Hsieh, C.-H.; Hsu, I.-J.; Lee, C.-M.; Ke, S.-C.; Wang, T.-Y.; Lee,
G.-H.; Wang, Y.; Chen, J.-M.; Lee, J.-F.; Liaw, W.-F. Inorg. Chem.
2003, 42, 3925.
(14) Greiwe, K.; Krebs, B.; Henkel, G. Inorg. Chem. 1989, 28, 3713.
11436 Inorganic Chemistry, Vol. 47, No. 23, 2008

Thiolatonitrosylmanganese Complexes
Scheme 2
1
oxidation level. The H NMR spectrum of complex 1a at
10-6 cm3 mol-1 for 2b (Figure S3b in the Supporting
Information), i.e., both centers having S ) 2 spins magneti-
cally couple to each other possibly via the direct metal d-d
orbital overlap (Mn1· · · Mn1A ) 3.365 Å) and the bridging
sulfurs [Mn1· · · S4 ) 2.594(1) Å for 2b].
298 K exhibits the paramagnetic shifts that appear at δ -8.16
(br), -22.95 (br) (S,S-C6H4), 3.62 (s), 1.78 (s) (C4H8O) ppm
(C4D8O). The temperature-independent effective magnetic
moment (µB) in the solid state by a SQUID magnetometer
was 4.84 µB for complex 1a (Figure S1 in the Supporting
Information), consistent with a total spin value (ST) of 2.
In contrast to the formation of the mononuclear, distorted
square-pyramidal complexes 1a and 1b in THF, the forma-
tion of the stable dimeric [Mn(S,S-C6H3-R)2]22- [R ) H (2a),
Me (2b)] was observed when complexes 1a and 1b were
dissolved in CH2Cl2, respectively (Scheme 2a). Coordinative
association of two anionic mononuclear [Mn(S,S-C6H3-R)2]-
complexes yielding complexes 2a and 2b in the absence of
a THF-coordinating solvent, respectively, is attributed to the
avoidance of electron deficiency at the MnIII centers as well
as to the availability of the nonbonding electron pairs of the
sulfur atoms in the [Mn(S,S-C6H3-R)2]- complex. In contrast
to the temperature-independent effective magnetic moment
observed in 1a, 2a shows that its µeff decreases from 4.68
µB at 300 K to 0.85 µB at 2.0 K (Figure S2 in the Supporting
Information) and 2b shows a decrease from 4.80 µB at 300
K to 0.64 µB, with 0.5 T applied field in both cases (Figure
S3a in the Supporting Information). Thus, the electronic
structures of complexes 2a and 2b can be best described as
two paramagnetic d4 MnIII cores with antiferromagnetic
coupling (J ) -52 cm-1) with TIP held constant at 200 ×
As presented in Scheme 2b, upon the addition of [BH4]-
into CH3CN of complexes 2a and 2b in a 2:1 stoichiometry
under nitrogen at room temperature, respectively, a reaction
ensued over the course of 3 h to yield the dianionic
mononuclear manganese thiolate complexes [Mn(S,S-C6H3-
R)2]2- [R ) H (3a), Me (3b)].14 Also, the temperature-
independent effective magnetic moment in the solid state
by a SQUID magnetometer was 6.15 µB for complex 3a,
which is consistent with the MnII ion having a high-spin d5
electronic configuration in a tetrahedral ligand field.15
Alternatively, treatment of complex 1a with 1 equiv of
[BH4]- in CH3CN for 1 h at ambient temperature also led
to the reduction of complex 1a to produce complex 3a
(Scheme 2c). Consistent with complex [(THF)Fe(S,S-
C6H4)2]-,15 complex 3a does not initiate O2 activation to yield
manganese sulfinate/sulfenate compounds identified by IR
νSO. Instead, purging of a THF solution of complex 3a by
O2 yielded complex 1a (Scheme 2c′).
Structures of Complexes 1a, 2b, and 3a. Figures 1-3
display the thermal ellipsoid plots of complexes 1a, 2b, and
3a, respectively, and selected bond distances and angles are
given in the figure captions. The O1-Mn-S3, O1-Mn-S4,
Inorganic Chemistry, Vol. 47, No. 23, 2008 11437

Lin et al.
Figure 2. ORTEP drawing of the anionic part ([Mn(S,S-C6H3-Me)2]22-) of complex 2b with thermal ellipsoids drawn at the 50% probability level. Selected
bond distances (Å) and angles (deg): Mn1-S3 2.2933(9), Mn1-S1 2.2978(9), Mn1-S2 2.999(9), Mn1-S4A 2.3411(9), Mn1· · ·S4 2.5938(10), Mn1· · ·Mn1A
3.365; S3-Mn1-S1 159.33(4), S3-Mn1-S2 86.09(3), S1-Mn1-S2 87.85(3), S3-Mn1-S4A 88.47(3).
Scheme 3
Figure 3. ORTEP drawing of the anionic part ([Mn(S,S-C6H4)2]2-) of
complex 3a with thermal ellipsoids drawn at the 50% probability level.
Selected bond distances (Å) and angles (deg): Mn-S1A 2.4230(5),
Mn-S1B 2.4230(5), Mn-S1 2.4230(5), Mn-S1C 2.4230(5); S1-Mn-S1C
88.50(2),S1C-Mn-S1A131.68(3),S1-Mn-S1A111.18(3),S1C-Mn-S1B
111.18(3), S1-Mn-S1B 131.68(3), S1B-Mn-S1A 88.50(2).
characterized by single-crystal X-ray analysis. Upon bubbling
of nitrogen into a THF solution of complex 4a, the identical
IR νNO stretching frequency and UV-vis absorption bands
demonstrated that complex 4a is stable under a nitrogen
atmosphere. In order to elucidate the valence state distribution
pattern of the {(L)2Mn(NO)}5 (L ) S,S-C6H3-R) core, the
criteria [the C-S bond distance of 1.735(6) Å and the
alternative patterns of two shorter CdC (ave 1.380 Å) as
well as four longer CdC bonds (ave 1.406 Å) denoting the
radical monoanion [L•]- electronic state (L ) 1,2-benzene-
dithiolate)] reported by Wieghardt and co-workers were
adopted.6,10 The C-S bond length of 1.745 Å in combination
with the alternative patterns of two shorter CdC (ave 1.375
Å) and four longer CdC (ave 1.403 Å) bonds implies the
existence of a π-radical monoanionic 1,2-benzenedithiolate
in complex 4a, as shown in Scheme 3. The temperature-
dependent effective magnetic moment (µeff) increases from
3.25 µB at 2.0 K to 4.77 µB at 300 K (Figure 4). These results
imply that the electronic structure of complex 4a may adopt
S3-Mn-S1, and S1-Mn-S4 bond angles of 99.07(9),
93.92(8), 87.57(4), and 171.17(5)°, respectively, are consis-
tent with the distorted square-pyramidal coordination envi-
ronment about manganese of complex 1a. The displaced
distance (0.2942 Å) of the manganese atom from the mean
four-sulfur-atom plane toward the axial THF was observed
in complex 1a. The dinuclear complex 2b is electronically
dianionic, and therefore both manganese atoms should be
MnIII. Complex 2b possesses crystallographically imposed
centrosymmetry. Two [Mn(S,S-C6H3CH3)2]- units are con-
nected via two thiolate bridges [Mn1 · · · S4 ) 2.594(1) Å]
in complex 2b. It is noticed that the average Mn-S bond
lengths of 2.3033(12) and 2.3080(9) Å in complexes 1a and
2b, respectively, are shorter than that of 2.4230(5) Å in
complex 3a (Table S1 in the Supporting Information). The
reduction of complex 1a to 3a (MnIII to MnII) was believed
to cause the elongation of the mean Mn-S bond distances.
The geometry of the manganese center of complex 3a is best
described as a distorted tetrahedral with S1-Mn-S1A,
S1-Mn-S1B, S1-Mn-S1C, and S1A-Mn-S1C bond
angles of 111.18(3), 131.68(3), 88.50(2), and 131.68(3)°,
respectively.
a
resonance hybrid of [(L)(L)MnIII(NO•)]- and
[(L)(L•)MnIII(NO-)]- electronic configurations in a square-
pyramidal ligand field.
When THF solutions of complexes 4a and 4b were treated
with 1 equiv of [S,NH2-C6H4]-, respectively, instead of the
direct nucleophilic attack of [S,NH2-C6H4]- on the coordi-
nated NO yielding [ON-S,NH2-C6H4] and [Mn(S,S-C6H3-
R)2]2-, UV-vis, IR spectra, and X-ray diffraction studies
confirmed the formation of the dianionic, mononuclear
{Mn(NO)}6 [(NO)Mn(S,S-C6H3-R)2]2- [R ) H (5a), Me
(5b)] accompanied by byproduct 2-aminophenyl disulfide
identified by 1H NMR (Scheme 2e). The temperature-
dependent effective magnetic moment (µeff) of complex 5a
increases from 2.86 µB at 2 K to 3.59 µB at 300 K (Figure
5). The most noteworthy characteristic of the reduction of
Syntheses of the Anionic {Mn(NO)}5 [(NO)Mn(S,S-C6H3-
R)2]- and Dianionic {Mn(NO)}6 [(NO)Mn(S,S-C6H3-R)2]2-
(R ) H, CH3). Upon bubbling of NO(g) (10% NO + 90%
N2) through THF solutions of complexes 1a and 1b,
respectively, IR [νNO: 1735 s (THF), 1727 s (KBr) cm-1 (4a)]
and UV-vis spectra implied the formation of the anionic
{Mn(NO)}5 complex [(NO)Mn(S,S-C6H3-R)2]- [R ) H (4a),
Me (4b); Scheme 2d]. Complex 4a was isolated and
11438 Inorganic Chemistry, Vol. 47, No. 23, 2008

Thiolatonitrosylmanganese Complexes
Figure 4. Plot of the effective magnetic moment (µB) vs temperature for complex 4a.
Figure 5. Plot of the effective magnetic moment (µB) vs temperature for complex 5a.
complex 4b is the disappearance of the low-energy absorp-
tion band at 740 nm with concomitant formation of 665 and
357 nm absorption bands. No optical evidence (based on
the UV-vis spectrum) for the presence of [S,S-C6H3R]• was
observed.10,15 It is believed that relief of the electron
deficiency of the {Mn(NO)} core due to reduction does not
require electronic compensation from the “redox-noninno-
cent” 1,2-benzenedithiolate(2-) ligand. The lower energy
νNO band [1650 cm-1 (KBr)] of complex 5b shifted by 76
cm-1 from that of complex 4b [1727 cm-1 (KBr)] implies
that the reduction process occurred in the {(L)(L•)MnIII} core.
These results indicate that the electronic structure of the
{Mn(NO)}6 core of complex 5b may exist as {(L)(L)-
MnIII(NO-)}, i.e., the {Mn(NO)}6 5b having a high-spin d4
MnIIINO- electronic configuration in a distorted square-
pyramidal ligand field,9 although the Mn1-N1-O1 bond
angle of 176.87(14)° in complex 4a is comparable to that of
177.2(6)° in complex 5a. Alternatively, when complex 3a
(or 3b) was treated with NO(g) (10% NO + 90% N2) in
CH3CN at room temperature, a rapid reaction ensued over
the course of 5 min to give the air-sensitive, deep-green
complex 5a (or 5b), as shown in Scheme 2f.
Magnetic Susceptibility Study. To further understand
the chemical properties of complexes 4a and 5a, the
detailed description of the electronic structure is impera-
tive, specifically, the oxidation states of manganese and
NO. In complex 4a, four possible electronic structures of
{(L)(•L)MnNO} (L ) 1,2-benzenedithiolate) with a radical
monoanion (•L) serving as a coligand can be depicted;
1
i.e., {(L)(•L)MnINO+} (S•L ) /2, SMn ) 2, SNO ) 0),
{(L)(•L)MnII(•NO)} (S•L
) ) )
1/2, SMn 5/2, SNO 1/2),
1
{(L)(•L)MnIIINO-} (S•L ) /2, SMn ) 2, SNO ) 1), and
Inorganic Chemistry, Vol. 47, No. 23, 2008 11439

Lin et al.
Figure 6. (a) Least-squares fit (R2 ) 0.982) to the ꢀM vs temperature (2-300 K) curve for complex 4a, shown as a solid line, giving J ) -25 cm-1, θ )
-0.8277 cm-1, g ) 2 (fixed), with TIP held constant at 200 × 10-6 cm3 mol-1. (b) Least-squares fit to the ꢀM vs temperature (2-300 K) curve for complex
5a, shown as a solid line, giving g ) 2 (fixed), |D| ) 2.05, and |E| ) 0.0473. (The values of D and E are shown by their absolute values because the sign
cannot be unambiguously determined by fitting of the powder susceptibility data). The results were fitted by using the program ANISOFIT (Shores, M. P.;
Sokol, J. J.; Long, J. R. J. Am. Chem. Soc. 2002, 124, 2279-2292; assuming that only the ground state is populated) including axial zero-field splitting (D),
rhombicity of the system (E), and Zeeman interactions and incorporate a full powder average.
{(L)(•L)MnIIINO-} (S•L ) /2, SMn ) 2, SNO ) 0).10c In
1
order to validate the most possible electronic structure of
{(L)(•L)MnNO}, a magnetochemical study suitable for
elucidating interactions of unpaired electrons in a spin-
coupled system was conducted. The spin Hamiltonian of
isotropic spin exchange of three-spin and two-spin centers,
respectively, can be expressed as
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
H3spin ) -J1SFe · SNO - J2SFe · SL - J3SNO · SL
(1)
(2)
Figure 7. ORTEP drawing of the anionic part ([(NO)Mn(S,S-C6H4)2]-)
of complex 4a with thermal ellipsoids drawn at the 50% probability level.
Selected bond distances (Å) and angles (deg): Mn1-N1 1.6355(14),
Mn1-S1 2.2579(5), Mn1-S2 2.2474(5), Mn1-S3 2.2793(5), Mn1-S4
2.2703 (5), N1-O1 1.1861(18); S3-Mn1-N1 99.56(5), S3-Mn1-S4
86.906(17),S2-Mn1-S187.882(18),S2-Mn1-S486.691(18),S1-Mn1-S4
150.220(19),S1-Mn1-S386.049(17),S3-Mn1-S2155.55(2),S2-Mn1-N1
104.55(5), S1-Mn1-N1 113.95(5), S4-Mn1-N1 95.75(5), O1-N1-Mn1
176.87(14).
ˆ
ˆ
ˆ
H2spin ) -JSFe · SL
Several attempts have been made to fit the magnetic
susceptibility data of complex 4a based on the electronic
structures described above. Results show that the electronic
structure of {(L)(•L)MnIIINO-} (S•L ) /2, SMn ) 2, SNO
1
)
0) fits the experimental susceptibility data (Figure 6a) because
the detailed comparisons of the average Mn-S bond
distances rule out the possibility of a {(L)(•L)MnINO+}
electronic structure (Tables S1 and S2 in the Supporting
Information). The analytical expression of ꢀm is given below
(ꢀm is the molar susceptibility, J is the exchange coupling
parameter, TIP is temperature-independent paramagnetism,
and θ is a Weiss-like temperature correction; all other terms
have their usual significances).
hybrid of [(L)(L)MnIII(NO•)]- and [(L)(L•)MnIII(NO-)]- (S•L
) 1/2, SMn ) 2, SNO ) 0) with intramolecular antiferromag-
netic coupling between manganese and radical monoanion
(•L)/nitric oxide (NO•), respectively. Also, because of the
low-energy absorption band (740 nm) tentatively assigned
as the existence of [S,S-C6H3R]•,10 we cannot rule out the
existence of the [(L)(L•)MnIII(NO-)]- resonance form in
complex 4a. Complex 5a is best characterized as a {(L)(L-
)MnIIINO-} (SL ) 0, SMn ) 2, SNO ) 0) electronic structure
possessing tetragonal distortion imposed by an axial NO-
ligand, consistent with the previous assignments.
Structures of Complexes 4a and 5a. X-ray crystal
structures of complexes 4a and 5a are depicted in Figures 7
and 8, respectively, and selected bond dimensions for both
complexes are presented in the figure captions. Analysis of
the bond angles for complex 4a reveals that the coordination
geometry of the manganese center is best described as a
distorted square pyramid with a linear apical NO and a
dihedral angle of 38° (between planes S1-Mn1-S2 and
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
H3spin ) -J1SFe · SNO - J2SFe · SL - J3SNO · SL
(3)
The magnetic behavior of complex 5a can also be fitted
properly by {(L)(L)MnIIINO-} (SL ) 0, SMn ) 2, and SNO
)
0; Figure 6b) modeled by spin Hamiltonian (4).
2
2
2
ˆ
ˆ
ˆ
ˆ
H ) DSz + E(Sx + Sy ) + gisoµBB · S
(4)
On the basis of the magnetochemical studies in combina-
tion with average Mn-S bond lengths of 2.2637(5) Å for
complex 4a and 2.259(1-2) Å for complex 5a, the electronic
structure of complex 4a may be best described as a resonance
11440 Inorganic Chemistry, Vol. 47, No. 23, 2008

Thiolatonitrosylmanganese Complexes
Figure 8. ORTEP drawing of the anionic part ([(NO)Mn(S,S-C6H4)2]2-
)
of complex 5a with thermal ellipsoids drawn at the 50% probability level.
Selected bond distances (Å) and angles (deg): Mn1-N1 1.607(6), Mn1-S1A
2.2966(14), Mn1-S2 2.2753(16), Mn1-S2A 2.2380(15), Mn1-S1
2.2249(15), N1-O1 1.206(8); Mn1-N1-O1 177.2(6), S1A-Mn1-N1
101.9(2), S1-Mn1-N1 100.8(2), S2A-Mn1-N1 100.3(2), S1A-Mn1-S1
157.29(5),S2-Mn1-N1102.4(2),S1A-Mn1-S286.57(5),S1A-Mn1-S2A
87.23(5), S2-Mn1-S2A 157.19(5), S2-Mn1-S1 88.07(6).
S3-Mn1-S4). The manganese atom is displaced from the
mean four-sulfur-atom plane (0.5304 Å for 4a). Compared
to the Mn-N(O) and N-O bond lengths of 1.6355(14) and
1.1861(18) Å, respectively, for {Mn(NO)}5 complex 4a,
relief of the electron deficiency from reduction may explain
the observed shortening and lengthening of the Mn-N(O)
and N-O bond lengths [1.607(6) and 1.206(8) Å, respec-
tively] for {Mn(NO)}6 complex 5a (Table S2 in the Sup-
porting Information). However, the average Mn-S bond
lengths are not affected by the electronic change going from
{Mn(NO)}5 to {Mn(NO)}6 [2.2637(5) Å for complex 4a vs
2.259(1-2) Å for complex 5a]. It is also noticed that the
N-O bond length of 1.206(8) Å in complex 5a, longer than
that of 1.186(18) Å in complex 4a, is nearly midway between
the N-O bond distance of 1.154 Å in free •NO and 1.26 Å
in NO-. Consistent with the previous discussion, the
electronic structure of the {Mn(NO)}6 core of complexes
5a is best described in terms of having a {MnIII(NO-)}6
core.9
Figure 9. ORTEP drawing of the anionic part ([Mn(S,S-C6H4)3]2-) of
complex 6a with thermal ellipsoids drawn at the 50% probability level.
Selected bond distances (Å) and angles (deg): Mn1-S4 2.3430(17),
Mn1-S5 2.3220(17), Mn1-S3 2.3355(15), Mn1-S2 2.3248(16), Mn1-S6
2.3270(16), Mn1-S1 2.3309(17); S4-Mn1-S5 103.36(6), S5-Mn1-S3
86.29(6), S2-Mn1-S4 85.37(6), S2-Mn1-S3 102.70(6), S5-Mn1-S6
85.46(6), S2-Mn1-S6 86.78(6), S4-Mn1-S1 167.62(6), S3-Mn1-S1
87.72(6), S6-Mn1-S1 100.59(6).
complexes 5a and 5b leading to the formation of complexes
4a and 4b, the major products [Mn(S,S-C6H3-R)3]2- [R ) H
(6a), Me (6b)], respectively, identified by IR, UV-vis, and
X-ray diffraction and the unidentified byproducts (presumably,
the NO-containing byproducts) were observed (Scheme 2e′ and
2h).18 Many attempts made to isolate and characterize the
proposed NO-containing byproducts (nitrite or nitrate) were
unsuccessful. Presumably, for the oxygen oxidation of the
{M(NO)}6 complexes, the electronic structures of the {M(NO)}6
centers (M ) Fe, Mn) (d6 FeII {FeII(NO+)}6 vs d4 MnIII
{MnIII(NO-)}6) appear to be crucial for the triggering of an
inner- or outer-sphere process.12
Structure of Complex 6a. The single-crystal X-ray struc-
ture of complex 6a is depicted in Figure 9, and selected bond
coordinates are presented in the figure caption. The geometry
of the manganese center is a distorted octahedral. The steric
effect among the chelating [S,S-C6H3R]2- ligands from the five-
coordinated MnIII complex 2b to the six-coordinated MnIV
complex 6a may rationalize an increase of mean Mn-S bond
distances of 0.023 Å (Table S1 in the Supporting Information).
Obviously, the longer Mn-S bond distances in complex 6a
indicate that the influence of the steric effect of the chelating
ligands overwhelms the contraction effect resulting from the
oxidation of MnIII (complexes 1a and 2b) to MnIV (complex
6a).
Synthesis of Complexes [Mn(S,S-C6H3-R)3]2- [R ) H
(6a), CH3 (6b)]. The oxygen oxidation reaction of complexes
3a and 3b in CH3CN led to the formation of complexes 2a
and 2b and the known [Mn(S,S-C6H3-R)3]2- [R ) H (6a),
Me (6b)] characterized by UV-vis and single-crystal X-ray
diffraction (Scheme 2g and 2b′).17 The H NMR spectrum
1
of complex 6b at 298 K exhibits the paramagnetic chemical
shifts that appear at δ -23.15 (br), -20.33 (br), 18.36 (br),
20.04 (br) (S,S-C6H3CH3) ppm (CD3CN). The effective
magnetic moment of complex 6b in the solid state, found
using the SQUID magnetometer, is from 2.57 µB at 2 K to
4.01 µB at 299 K (Figure S4 in the Supporting Information).
These results support the idea that complex 6a (or 6b) adopts
a d3 MnIV electronic configuration in a distorted octahedral
ligand field.
Conclusion and Comments
To follow up on our earlier study with a better understanding
of the reactivity of the {M(NO)}n (M ) transition metal; n )
6,7)-nitrosylated metal thiolates toward oxygen, the reaction of
complexes 5a and 5b and oxygen was investigated. In contrast
to the {Fe(NO)}6 complex [(NO)Fe(S,S-C6H4)2]- triggering
sulfur oxygenation yielding the S-bonded monosulfinate iron
nitrosyl species,15 an attack of oxygen on the {Mn(NO)}6
The anionic mononuclear {Mn(NO)}5 thiolatonitrosylman-
ganese complex 4a was obtained from nitrosylation of the
(18) (a) Grapperhaus, C. A.; Darensbourg, M. Y. Acc. Chem. Res. 1998,
31, 451. (b) Kovacs, J. A. Chem. ReV. 2004, 104, 825. (c) Harrop,
T. C.; Mascharak, P. K. Coord. Chem. ReV. 2005, 249, 3007. (d) Lugo-
Mas, P.; Dey, A.; Xu, L.; Davin, S. D.; Benedict, J.; Kaminsky, W.;
Hodgson, K. O.; Hedman, B.; Solomon, E. I.; Kovacs, J. A. J. Am.
Chem. Soc. 2006, 128, 11211. (e) Chohant, B. S.; Maroney, M. J.
Inorg. Chem. 2006, 45, 1906.
(17) Bressel, U.; Katritzky, A. R.; Lea, J. R. J. Chem. Soc. A 1969, 2258.
Inorganic Chemistry, Vol. 47, No. 23, 2008 11441

Lin et al.
solution was added to a THF solution (5 mL) of MnBr2 (1 mmol,
0.215 g) via cannula under nitrogen. After the reaction solution
was stirred for another 2 h at ambient temperature, the red-brown
mixture solution was then transferred to another Schlenk flask
containing [Et4N][Br] (2 mmol, 0.420 g) or [PPN][Cl] (2 mmol,
1.148 g). The reaction solution was then stirred overnight, and the
mixture solution was filtered through Celite to remove NaBr (NaCl)
and the insoluble solid. Diethyl ether was then added into the filtrate
to precipitate the reddish-brown solid [cation][(THF)Mn(L)2] [THF
) tetrahydrofuran, L ) 1,2-benzenedithiolate, cation ) PPN + (1a);
toluene-3,4-dithiolate, cation ) Et4N+ (1b)] (yield 61% for 1a and
55% for 1b). Diffusion of diethyl ether into a THF solution of
complex 1a at -15 °C for 3 days yielded reddish-brown crystals
suitable for X-ray crystallography. Complex 1a. 1H NMR (C4D8O):
δ 3.62 (s), 1.78 (s) (C4H8O), -8.16 (br), -22.95 (br) (S,S-C6H4)
ppm. Absorption spectrum (THF) [λmax, nm (ꢀ, M-1 cm-1)]: 352
(14 837), 540 (748). Anal. Calcd for C52H46MnNOP2S4: C, 66.00;
H, 4.86; N, 1.45. Found: C, 66.02; H, 4.75; N, 1.49. Complex 1b.
Absorption spectrum (THF) [λmax, nm (ꢀ, M-1 cm-1)]: 355 (19 215),
552 (986).
anionic complex 1a. Reduction of complex 4a yielded the
dianionic mononuclear {Mn(NO)}6 complex 5a. The coordina-
tion environment of [MnS4(NO)] units and the average Mn-S
bond lengths remain intact when complexes 4a and 4b were
reduced to yield 5a and 5b, respectively; however, the observed
shortening and lengthening of the Mn-N(O) and N-O bond
lengths [1.607(6) and 1.206(8) Å, respectively] for {Mn(NO)}6
complex 5a, compared to the Mn-N(O) and N-O bond lengths
of 1.6355(14) and 1.1861(18) Å for {Mn(NO)}5 complex 4a,
may rationalize relief of the electron deficiency of the {Mn-
(NO)} core by the electronic change going from {Mn(NO)}5
to {Mn(NO)}6. X-ray structural data, the IR νNO spectrum,
magnetic measurements, and magnetic fitting results suggest
that the electronic structure of complex 4a is best described as
the resonating forms of A, B, and C, with major contributions
from B and C forms, as shown in Scheme 1. Also, IR, UV-vis,
and magnetic susceptibility measurements suggest that the
electronic structure of the {Mn(NO)}6 core of complexes 5a
and 5b may exist as {(L)(L)MnIII(NO-)}, i.e., the {Mn(NO)}6
having a high-spin d4 MnIIINO- electronic configuration in a
distorted square-pyramidal ligand field.9 In contrast to the
{Fe(NO)}6 [(NO)Fe(S,S-C6H4)2]- initiating sulfur oxygenation
of iron thiolate by molecular oxygen to yield S-bonded
monosulfinate iron complex [(NO)Fe(SO2,S-C6H4)(S,S-
C6H4)]-,15 oxygen oxidation of the {Mn(NO)}6 complex 5a
led to the formation of complex 4a and the major product 6a
identified by IR, UV-vis, and X-ray diffraction. Presumably,
factors contributing to the distinct oxidation pathways are
attributed to the different electronic structures of the {M(NO)}6
core (M ) Fe, Mn) between {Fe(NO)}6 complex [(NO)Fe(S,S-
C6H4)2]- (d6 FeII {FeII(NO+)}6) and {Mn(NO)}6 complexes 5a
and 5b (d4 MnIII {MnIII(NO-)}6, the weaker Mdπ-Spπ interac-
tion).18
Preparation of [cation]2[Mn(L)2]2 [L ) 1,2-benzenedithiolate,
+
cation ) PPN
(2a); toluene-3,4-dithiolate, cation ) Et4N+
(2b)]. Complex 1a (0.4 mmol, 0.378 g) or complex 1b (0.4 mmol,
0.224 g) was loaded into a 20-mL Schlenk tube, and then 15 mL
of the degassed CH2Cl2 was added via cannula under positive
nitrogen. CH2Cl2 solutions of complexes 1a and 1b were stirred
for 10 min at ambient temperature, and then the solution was filtered
through Celite to remove the insoluble solid. Diethyl ether was
added to precipitate the red-brown solid [PPN]2[Mn(L)2]2 [L ) 1,2-
benzenedithiolate (2a); toluene-3,4-dithiolate, cation ) Et4N+ (2b)]
(yield 80% for 2a and 78% for 2b). Diffusion of diethyl ether into
CH2Cl2 solutions of complexes 2a and 2b at -15 °C yielded red-
brown crystals suitable for single-crystal X-ray diffraction. Complex
2a. 1H NMR (CD2Cl2): δ -24.57 (br), -4.17 (br) (S,S-C6H4) ppm.
Absorption spectrum (CH2Cl2) [λmax, nm (ꢀ, M-1 cm-1)]: 538
(1458), 639 (426), 895 (193). Anal. Calcd for C96H76Mn2N2P4S8:
C, 65.96; H, 4.38; N, 1.6. Found: C, 65.82; H, 4.30; N, 1.41.
Complex 2b. Absorption spectrum (CH2Cl2) [λmax, nm (ꢀ,
M-1cm-1)]: 538 (2952), 639 (196), 895 (90).
Experimental Section
Manipulations, reactions, and transfers of samples were conducted
under nitrogen according to standard Schlenk techniques or in a
glovebox (nitrogen gas). Solvents were distilled under nitrogen from
appropriate drying agents [diethyl ether from CaH2, acetonitrile from
CaH2-P2O5, methylene chloride from P2O5, hexane and tetrahydro-
furan (THF) from sodium benzophenone] and stored in dried, nitrogen-
filled flasks over 4 Å molecular sieves. Nitrogen was purged through
these solvents before use. The solvent was transferred to a reaction
vessel via a stainless steel cannula under positive pressure of nitrogen.
The reagents 1,2-benzenedithiol, toluene-3,4-dithiol, sodium methoxide,
bis(triphenylphosphine)iminium chloride, manganese(II) bromide, tet-
raethylammonium chloride, and bis(triphenylphosphine)iminium boro-
hydride (Lancaster/Acros/Aldrich/Fluka) were used as received. IR
spectra of the πNO stretching frequencies were recorded on a Perkin-
Elmer model Spectrum One B spectrophotometer with sealed solution
cells (0.1 mm) and KBr windows. UV-vis spectra were recorded on
GBC Cintra 10e and Hewlett-Packard 71 spectrophotometers. Analyses
of carbon, hydrogen, and nitrogen were obtained with a CHN analyzer
(Heraeus).
Preparation of [cation]2[Mn(L)2] [L ) 1,2-benzenedithiolate,
cation ) PPN
+
(3a); toluene-3,4-dithiolate, cation ) Et4N+
(3b)]. Complex 2a (0.4 mmol, 0.564 g) or complex 2b (0.4 mmol,
0.394 g) was loaded into a 20-mL Schlenk tube, and the degassed
CH3CN (9 mL) was added via cannula under positive nitrogen.
The CH3CN solution of complex 2a was then transferred slowly
into another Schlenk flask containing [PPN][BH4] (1 mmol, 0.553
g) or [Et4N][BH4] (1 mmol, 0.145 g) via cannula under positive
nitrogen. The resulting mixture was stirred for 5 min at room
temperature, and then the light-yellow mixture solution was filtered
through Celite to remove the insoluble solid. Degassed diethyl ether
was added into the filtrate to precipitate the light-yellow solid
[PPN]2[Mn(L)2] (3a; L ) 1,2-benzenedithiolate) (yield 37%).15
Diffusion of diethyl ether into a CH3CN solution of complex 3a at
room temperature yielded light-yellow crystals suitable for X-ray
crystallography. Complex 3a. Absorption spectrum (CH3CN) [λmax
,
nm (ꢀ, M-1 cm-1)]: 521 (444), 370 (8895). Anal. Calcd for
C84H68MnN2P4S4: C, 71.42; H, 4.85; N, 1.98. Found: C, 70.82; H,
4.89; N, 2.08. Complex 3b. Absorption spectrum (CH3CN) [λmax
,
Preparation of [cation][(THF)Mn(L)2] [THF ) tetrahydrofu-
ran, L ) 1,2-benzenedithiolate, cation ) PPN + (1a); toluene-3,4-
dithiolate, cation ) Et4N+ (1b)]. A MeOH solution (7 mL) of
[Na][OMe] (4 mmol, 0.216 g) was added slowly to toluene-3,4-
dithiol (2 mmol, 246 µL) or 1,2-benzenedithiol (2 mmol, 260 µL).
After the reaction solution was stirred for 20 min, the mixture
nm (ꢀ, M-1 cm-1)]: 521 (865), 370 (8355).
Preparation of [cation][(NO)Mn(L)2] [L ) 1,2-benzenedithi-
olate, cation ) PPN+ (4a); toluene-3,4-dithiolate, cation ) Et4N+
(4b)]. The THF solution (15 mL) of complex 1a (0.4 mmol, 0.378
g) was purged by NO(g) (10% NO + 90% N2) for 5 min at 0 °C,
11442 Inorganic Chemistry, Vol. 47, No. 23, 2008

Thiolatonitrosylmanganese Complexes
and then the solution was stirred for 10 min at 0 °C. Degassed
diethyl ether was then added to precipitate the deep-brown solid
[PPN][(NO)Mn(L)2] (4a; L ) 1,2-benzenedithiolate) (yield 91%).
Diffusion of diethyl ether into a THF solution of complex 4a at
-15 °C yielded deep-brown crystals suitable for X-ray crystal-
lography. Complex 4a. IR νNO: 1735 s cm-1 (THF), 1729 s cm-1
(KBr). Absorption spectrum (CH2Cl2) [λmax, nm (ꢀ, M-1 cm-1)]:
727 (1369). Anal. Calcd for C48H38MnN2OP2S4: C, 63.78; H, 4.24;
dithiolate, cation ) Et4N+ (6b)]. Complex 6b. 1H NMR (CD3CN):
δ 20.04 (br), 18.36 (br), -20.33 (br), -23.15 (br) (S,S-C6H4CH3)
ppm. Absorption spectrum (CH3CN) [λmax, nm (ꢀ, M-1 cm-1)]: 363
(8436), 508 (1916), 582 (1488), 741 (1265). Anal. Calcd for
C37H58N2S6Mn: C, 57.14; H, 7.46; N, 3.60. Found: C, 57.26; H,
7.88; N, 3.15. Complex 6a. Absorption spectrum (CH3CN) [λmax
,
nm (ꢀ, M-1 cm-1)]: 363 (8530), 502 (1328), 575 (1032), 727 (736).
Diffusion of diethyl ether into a CH3CN solution of complex 6a at
room temperature yielded dark-green crystals suitable for X-ray
crystallography.
N, 3.10. Found: C, 63.07; H, 4.71; N, 2.48. Complex 4b. IR νNO
:
1735 s cm-1 (THF), 1727 s cm-1 (KBr). Absorption spectrum
(CH2Cl2) [λmax, nm (ꢀ, M-1 cm-1)]: 740 (1483).
Magnetic Measurements. The magnetic data were recorded on
a SQUID magnetometer (MPMS5 Quantum Design Co.) under a 0.5
T external magnetic field in the temperature range of 2-300 K for
complexes 1a, 2a, 2b, 4a, and 5a (2-299 K for complex 6b). The
magnetic susceptibility data were corrected with TIP (2 × 10-4 cm3
mol-1) and ligands’ diamagnetism by the tabulated Pascal’s constants.19
Crystallography. Crystallographic data of complexes 1a, 2b, 3a,
4a, 5a, and 6a are summarized in the Supporting Information. The
crystals of 1a, 2b, 3a, 4a, 5a, and 6a are chunky. Each crystal was
mounted on a glass fiber. Diffraction measurements for complexes
2b and 4a were carried out at 100(2) K on a CCD area detector [150(2)
K for complexes 5a and 6a on a Nonius Kappa CCD, 293(2) K for
1a on a CAD4 diffractometer (point detector), and 150(2) K for
complex 3a] on a Bruker SMART Apex CCD diffractometer with
graphite-monochromated Mo KR radiation (λ 0.7107 Å) and θ between
1.63 and 25.00° for complex 1a, between 1.47 and 28.36° for complex
2b, between 1.66 and 27.50° for complex 3a, between 1.27 and 28.31°
for complex 4a, between 2.18 and 27.50° for complex 5a, and between
1.56 and 27.50° for complex 6a. In the case of complex 5a, Mn and
NO were found at disordered positions (shown in the crystallographic
data), and only one of the disordered positions is shown in Figure 8.
Least-squares refinement of the positional and anisotropic thermal
parameters for the contribution of all non-hydrogen and hydrogen
atoms was fixed at calculated positions and refined as riding models.
An absorption corrections were made for 1a (PSI-SCAN), 2b (Empiri-
cal), 3a (SADABS20), 4a (Empirical), and 5a and 6a (SORTAV21). The
SHELXTL22 structure refinement program was employed.
Preparation of [cation]2[(NO)Mn(L)2] [L ) 1,2-benzenedithi-
olate, cation ) PPN+ (5a); toluene-3,4-dithiolate, cation ) Et4N+
(5b)]. NO(g) (10% NO + 90% N2) was purged through the
CH3CN-MeOH (light-yellow) solutions of complexes 3a and 3b,
freshly prepared from the addition of CH3CN solutions (9 mL) of
complexes 2a and 2b (0.5 mmol) into a MeOH solution (3 mL) of
[PPN][BH4] (1 mmol, 0.553 g) or [Et4N][BH4] (1 mmol, 0.145 g)
and stirred for 5 min at ambient temperature. A significant change
in color of the reaction solution from light-yellow to deep-green
was observed. The solution was filtered through Celite to remove
the insoluble solid. Diethyl ether (25 mL) was added to precipitate
the deep-green solid [cation]2[(NO)Mn(L)2] [L ) 1,2-benzenedithi-
olate, cation ) PPN+ (5a); toluene-3,4-dithiolate, cation ) Et4N+
(5b)] (yield 85% for 5a and 78% for 5b). Diffusion of diethyl ether
into CH3CN solutions of complexes 5a and 5b at room temperature
yielded deep-green crystals suitable for X-ray crystallography.
Complex 5b. IR νNO: 1648 s cm-1 (CH3CN), 1651 s cm-1 (KBr).
Absorption spectrum (CH3CN) [λmax, nm (ꢀ, M-1 cm-1)]: 362
(6621), 667 (1569). Anal. Calcd for C30H52N3OS4Mn: C, 55.13;
H, 7.96; N, 6.43. Found: C, 54.69; H, 8.32; N, 6.09. Complex 5a.
IR νNO: 1651 s cm-1 (CH3CN), 1651 s cm-1 (KBr). Absorption
spectrum (CH3CN) [λmax, nm (ꢀ, M-1 cm-1)]: 357 (6581), 665
(2274). Alternatively, complex 4a (0.4 mmol, 0.362 g) or complex
4b (0.4 mmol, 0.210 g) was loaded into a 20-mL Schlenk tube,
and the degassed CH3CN (9 mL) was added via cannula under
positive nitrogen. The CH3CN solution of complexes 4a and 4b
were then transferred slowly into another Schlenk flask containing
a CH3CN solution (3 mL) of [PPN][S,NH2-C6H4] (0.4 mmol, 0.265
g) via cannula under positive nitrogen. The resulting mixture
solution was stirred for 2 h at room temperature, and the color of
the solution changed from deep-brown to deep-green. Diethyl ether
(25 mL) was then added to precipitate the deep-green solid 5a and
5b. The solution was then separated from the deep-green solid and
dried under vacuum to give 2-aminophenyl disulfide identified by
1H NMR.
Acknowledgment. We gratefully acknowledge financial
support from the National Science Council of Taiwan and
facilities from the National Center for High-performance
Computing.
Supporting Information Available: X-ray crystallographic files
in CIF format for the structure determinations of [PPN][(TH-
F)Mn(S,S-C6H4)2], [Et4N]2[Mn(S,S-C6H3CH3)2]2, [PPN]2[Mn(S,S-
C6H4)2], [PPN][(NO)Mn(S,S-C6H4)2], [PPN]2[(NO)Mn(S,S-C6H4)2],
and [PPN]2[Mn(S,S-C6H4)3], plots of the effective magnetic moment
(µB) versus temperature for complexes 1a, 2a, 2b, and 6b, and tables
of bond lengths and angles and of crystal data and structure
refinement. This material is available free of charge via the Internet
at http://pubs.acs.org.
Preparation of Complex [cation]2[Mn(L)3] [L ) 1,2-benzene-
+
dithiolate, cation ) PPN (6a); toluene-3,4-dithiolate, cation )
Et4N+ (6b)]. Pure oxygen gas (10 mL) was injected into CH3CN
solutions of complexes 5a and 5b (0.4 mmol), and then the reaction
solution was stirred for 30 min at room temperature. A significant
change in the color of the reaction solution from deep-green to
dark-green was observed, and then the solution was filtered through
Celite to remove the insoluble solid. Degassed diethyl ether (25
mL) was added to precipitate the dark-green solid. The filtrate (red-
brown solution) was dried under vacuum and redissolved in THF.
Hexane was then added to precipitate the red-brown solid identified
by IR and UV-vis as complexes 4a and 4b. The dark-green solid
IC801553S
(19) (a) O’Connor, C. J. Prog. Inorg. Chem. 1982, 29, 203. (b) Bain, G. A.;
Berry, J. F. J. Chem. Educ. 2008, 85, 532–536.
(20) Sheldrick, G. M. SADABS, Siemens Area Detector Absorption Cor-
rection Program; University of Go¨ttingen: Go¨ttingen, Germany, 1996.
(21) SORTAV: Blessing, R. H. Acta Crystallogr., Sect A: Fundam.
Crystallogr. 1995, 51, 33.
was characterized by UV-vis as complexes [cation]2[Mn(L)3] [L
(22) Sheldrick, G. M. SHELXTL, Program for Crystal Structure Determi-
nation; Siemens Analytical X-ray Instruments Inc.: Madison, WI, 1994.
+
) 1,2-benzenedithiolate, cation ) PPN
(6a); toluene-3,4-
Inorganic Chemistry, Vol. 47, No. 23, 2008 11443