Redox-Active phosphorus ligands bearing a [4Fe-4C] core substituent

Article abstract of DOI:10.1021/om900811u

Reaction of [(n⁵-C₅H₄Me) ₄Fe₄(HCCH)(HCCBr)](PF₆) (1) with HPPh ₂ in the presence of NEt₃, followed by treatment of [Cp₂Co], afforded [(n⁵-C₅

Full text of DOI:10.1021/om900811u

Organometallics 2009, 28, 7055–7058 7055
DOI: 10.1021/om900811u
Redox-Active Phosphorus Ligands Bearing a [4Fe-4C] Core Substituent
Masaaki Okazaki,*,† Ken-ichi Yoshimura, Masato Takano, and Fumiyuki Ozawa*
International Research Center for Elements Science (IRCELS), Institute for Chemical Research, Kyoto
University, Uji, Kyoto 611-0011, Japan. †Present address: Graduate School of Science and Technology,
Hirosaki University, Hirosaki 036-8561, Japan.
Received September 16, 2009
Summary: Reaction of [(η5-C5H4Me)4Fe4(HCCH)(HCCBr)]-
Scheme 1
(PF6) (1) with HPPh2 in the presence of NEt3, followed by
treatment of [Cp2Co], afforded [(η5-C5H4Me)4Fe4(HCCH)-
(HCC-PPh2)] (2). The electron-rich [4Fe-4C] core substituent
leads to the extremely electron-releasing character of the phos-
phine part, estimated by the JPSe coupling constant of the
corresponding selenide [(η5-C5H4Me)4Fe4(HCCH)(HCC-
P(Se)Ph2)] (3). Reaction of 2with [AuCl(SMe2)] gave [(η5-C5H4-
Me)4Fe4(HCCH)(HCC-P(AuCl)Ph2)] (4). The cyclic voltam-
mogram of 4 shows two reversible one-electron oxidation waves,
indicating the existence of one- and two-electron oxidized forms.
Introduction
The design of ancillary ligands is crucial for realizing the
efficient catalysis of homogeneous transition-metal complexes.
C5H4Me)4Fe4(HCCH)(HCC-PPh2)](PF6) ([2](PF6)) in 65%
yield (Scheme 1).5 Further treatment of [2](PF6) with [Cp2Co]
resulted in a one-electron reduction to give 2 in 97% yield. As
Incorporation of a redox-responsive functionality into a frame-
work of ligands enables alternation of reactivity and selectivity
of metal centers through the chemical or electrochemical mod-
expected from the odd number of cluster electrons of [2](PF6),
the 31P NMR signal exhibits a characteristic paramagnetic
shift (δ -281) and line-broadening (W1/2 = 173 Hz), while the
ification of redox states.1 Such a redox-active phosphorus ligand
has been developed by the introduction of mononuclear
transition-metal complexes.2 Wrighton et al. reported a repre-
sentative example using a rhodium complex coordinated
diamagnetic species 2 has a sharp signal at δ 51.6.
To estimate the s character of the lone pair orbital of 2, the
by 1,10-bis(diphenylphosphino)cobaltocene that can switch
catalytic activity between hydrosilylation and hydrogenation
1
coupling constant JPSe of phosphine selenide [(η5-C5H4-
Me)4Fe4(HCCH)(HCC-P(Se)Ph2)] (3) was measured.6
Cluster 3 was synthesized by the reaction of 2 with selenium
in dichloromethane at room temperature (Scheme 1). Table 1
of alkenes upon the redox change of the cobaltocene moiety.2a
Considering the multiple redox properties of transition-metal
clusters, it is expected that the introduction of polymetallic
lists the results in addition to those of other phosphine
cores3 could provide a new type of ancillary ligand subject to
multistep tuning of catalytic behavior. Herein, we report the
synthesis and properties of a redox-active phosphorus ligand
selenides. The average value of the C-P-C angles is calc-
ulated on the basis of X-ray diffraction analysis of 3
1
(Figure 1). The JPSe value of 3 (693 Hz) is significantly
smaller than those of R3PdSe (R = Ph, Cy, and tBu), which
indicates the smaller s character of the lone pair orbital of 2.
Thus, it is considered that 2 exhibits a significant electron-
releasing character compared with other well-known tertiary
phosphines. The average of the three C-P-C angles is
smaller than those of R3PdSe; therefore, the electron-releasing
character is mainly attributable to the electron-rich
[4Fe-4C] core; a cyclic voltammogram of [(η5-C5H4Me)4-
Fe4(HCCH)2] shows a reversible one-electron oxidation
wave at E1/2 = -0.86 V vs Fc/Fcþ.7 The low value of E1/2
implies an electron-rich [4Fe-4C] core. The strong σ-donor
bearing a [4Fe-4C] core substituent, its complexation with
gold, and the resultant structure.
Results and Discussion
Reaction of [(η5-C5H4Me)4Fe4(HCCH)(HCC-Br)](PF6)
(1)4 with HPPh2 in the presence of NEt3 afforded [(η5-
*To whom correspondence should be addressed. E-mail: mokazaki@
cc.hirosaki-u.ac.jp; ozawa@scl.kyoto-u.ac.jp.
(1) (a) Allgeier, A. M.; Mirkin, C. A. Angew. Chem., Int. Ed. 1998, 37,
894. (b) Geiger, W. E. Organometallics 2007, 26, 5738.
(2) (a) Lorkovic, I. M.; Duff, R. R., Jr.; Wrighton, M. S. J. Am. Chem.
Soc. 1995, 117, 3617. (b) S€ussner, M.; Plenio, H. Angew. Chem., Int. Ed.
2005, 44, 6885. (c) Gregson, C. K. A.; Gibson, V. C.; Long, N. J.; Marshall, E.
L.; Oxford, P. J.; White, A. J. P. J. Am. Chem. Soc. 2006, 128, 7410.
(3) Construction of functional molecules with polymetallic cores
have been reported in the following papers: (a) Albinati, A.; Fabrizi
de Biani, F.; Leoni, P.; Marchetti, L.; Pasquali, M.; Rizzato, S.; Zanello,
P. Angew. Chem., Int. Ed. 2005, 44, 2. (b) Aranzaes, J. R.; Belin, C.; Astruc,
D. Angew. Chem., Int. Ed. 2006, 45, 132.
(5) Compound [2](PF6) was also synthesized in 46% yield by the
reaction of 1 with LiPPh2 in acetonitrile.
(6) (a) Allen, D. W.; Taylor, B. F. J. Chem. Soc., Dalton. Trans. 1982,
51. (b) Tsuji, H.; Inoue, T.; Kaneta, Y.; Sase, S.; Kawachi, A.; Tamao, K.
Organomeallics 2006, 25, 6142.
(4) (a) Takano, M.; Okazaki, M.; Tobita, H. J. Am. Chem. Soc. 2004,
126, 9190. (b) Okazaki, M.; Takano, M.; Yoshimura, K. J. Organomet.
Chem. 2005, 690, 5318.
(7) (a) Okazaki, M.; Ohtani, T.; Inomata, S.; Tagaki, N.; Ogino, H.
J. Am. Chem. Soc. 1998, 120, 9135–9138. (b) Okazaki, M.; Ohtani, T.;
Takano, M.; Ogino, H. Inorg. Chem. 2002, 41, 6726.
r
2009 American Chemical Society
Published on Web 11/10/2009
pubs.acs.org/Organometallics

7056 Organometallics, Vol. 28, No. 24, 2009
Okazaki et al.
Table 1. 31P NMR Parameters and C-P-C Angles for R3PdSe
Ph3PdSe
tBu3PdSe
Cy3PdSe
3
1J(P-Se)/Hz
C-P-C/deg
755
105.7
708
110.0
706
108.3
693
107.5
Figure 2. ORTEP drawing of 4 with thermal ellipsoids at 50%
probability. All hydrogen atoms and methyl groups on η5-
C5H4Me ligands are omitted for clarity. Selected bond distances
˚
(A) and angles (deg): Fe1-Fe2 2.5158(7), Fe2-Fe3 2.5134(8),
Fe3-Fe4 2.4969(9), Fe4-Fe1 2.5300(8), C1-C2 1.511(4),
C3-C4 1.504(4), P-C1 1.840(3), Au-P 2.2466(7), Au-Cl
2.3006(8), P-Au-Cl 176.56(5).
Figure 1. ORTEP drawing of 3 with thermal ellipsoids at 50%
probability. All hydrogen atoms and methyl groups on η5-
C5H4Me ligands are omitted for clarity. Selected bond distances
Table 2. Cyclic Voltammetry Results for 4a
˚
(A) and angles (deg): Fe1-Fe3 2.5329(12), Fe1-Fe4 2.5062(12),
Epa, V
Epc, V
E1/2, V
ΔEp, mV
Fe2-Fe3 2.4981(11), Fe2-Fe4 2.5048(11), P-Se 2.1239(14),
P-C1 1.841(5), P-C29 1.839(5), P-C35 1.838(5), C1-C2
1.503(6), C3-C4 1.490(8), C1-P-C35 107.7(2), C1-P-C29
112.8(2), C29-P-C35 102.1(2).
[4]2þ/[4]þ
[4]þ/[4]0
þ0.54
-0.32
þ0.48
-0.38
þ0.51
-0.35
61
65
a Conditions: solution of 4 (0.1 mM) in acetonitrile with 0.1 M
[NnBu4]BF4 as supporting electrolyte; scan rate 50 mV s-1. Potentials
are given in V vs Fc/Fcþ.
Scheme 2
electron-rich [4Fe-4C] core. For instance, the reaction of
[2](PF6) with [AuCl(SMe2)] provided a one-electron oxidized
form of 4, [(η5-C5H4Me)4Fe4(HCCH)(HCC-P(AuCl)Ph2)]-
(PF6) ([4](PF6)), in 83% yield. The 31P{1H} NMR spectrum
of [4](PF6) shows a broad signal at δ -456 (W1/2 = 276 Hz),
characteristic of paramagnetism. Although the quality of
X-ray diffraction data was low (R1 = 0.091), the structure of
the one-electron oxidized form [4](PF6) was determined by
X-ray diffraction study (see Supporting Information). The
asymmetric unit consists of two independent molecules of
[4](PF6). The average of the Au-P bond distances (2.269(3)
2 would allow for the development of wide-scope catalytic
systems.8
Reaction of 2 with [AuCl(SMe2)] in dichloromethane at
room temperature gave [(η5-C5H4Me)4Fe4(HCCH)-
(HCC-P(AuCl)Ph2)] (4) in 77% yield (Scheme 2). The 31P
NMR signal of 4 appears at δ 62.2. The signal is shifted to the
downfield region by 10.6 ppm from 2 upon coordination to
the Au(I) center. The structure of 4 was determined by X-ray
diffraction analysis (Figure 2). Complex 4 adopts an almost
linear geometry, typical for two-coordinated Au(I) species;
the angle of P-Au-Cl is 176.56(5)°. The bond distance of
˚
A) is considerably longer than that in the neutral form 4
˚
(2.2466(7) A). Removal of one electron from the [4Fe-4C]
core weakens the σ-donation of [2](PF6) to the Au(I) center.
Rauchfuss and his co-workers described the introduction
of functional groups onto the Cp ligand of [Cp4Fe4(CO)4]
through deprotonation with lithium diisopropylamide
(LDA) followed by treatment with electrophiles.10 The use
of PPh2Cl afforded [(η5-C5H4PPh2)Cp3Fe4(CO)4], which
further ligated with the Ru(II) center through P-coordina-
tion to give [(η5-C5H4PPh2)Cp3Fe4(CO)4RuCl2(cymene)].
Due to the highly electron-rich character of [(C5H4Me)4-
Fe4(HCCH)2], the methodology involving deprotonation of
the cyclopentadienyl ligand10,11 was not operative in our
system. The direct introduction of the functional group onto
˚
Au-P (2.2466(7) A) lies within the range observed for
9
˚
[AuCl(PR3)] (2.20-2.25 A).
The cyclic voltammogram of 4 exhibits two reversible one-
electron oxidation waves (Table 2). These oxidation pro-
cesses are attributable to the removal of electrons from the
(8) (a) de Meijere, A.; Diederich, F. Metal-Catalyzed Cross-Coupling
Reactions; Wiley-VCH: Weinheim, Germany, 2004; 2 volumes. (b) Grubbs,
R. H. Handbook of Metathesis; Wiley-VCH: Weinheim, Germany, 2003; 3
volumes.
(9) Based on a survey of the Cambridge Structural Database, CSD
version 5.30; The Cambridge Crystallographic Data Centre: Cambridge,
U.K., Nov 2008.
(10) Westmeyer, M. D.; Massa, M. A.; Rauchfuss, T. B.; Wilson, S.
R. J. Am. Chem. Soc. 1998, 120, 114.
(11) Yeh, W.-Y.; Wu, C.-Y.; Chiou, L.-W. Organometallics 1999, 18,
3547.

Note
Organometallics, Vol. 28, No. 24, 2009 7057
the cluster core presented here is promising for the construc-
tion of functional polymetallic molecules with redox respon-
sibility.
pellet, cm-1): 2961 (w), 2925 (w), 1483 (m), 1434 (m), 1373 (m),
1262 (m), 1092 (m), 1029 (m), 844 (vs), 747 (m), 702 (m), 557 (s).
Synthesis of [(η5-C5H4Me)4Fe4(HCCH)(HCC-PPh2)] (2).
Cobaltocene (53 mg, 0.28 mmol) was added to a solution of
[2](PF6) (250 mg, 0.271 mmol) in acetonitrile (12 mL) at room
temperature. The solution was stirred for 1 h and was concen-
trated to dryness under vacuum. The residue was extracted with
diethyl ether. Removal of the solvent from the extract under
vacuum gave a dark brown solid of [(η5-C5H4Me)4Fe4(HCCH)-
(HCC-PPh2)] (2). Yield: 204 mg (97%). Data of 2: Anal. Calcd
for C40H41Fe4P: C, 61.90; H, 5.32. Found: C, 61.70; H, 5.32.
Mass (FAB): m/z 776 (Mþ, 100), 591 (Mþ - PPh2, 82). 1H NMR
(C6D6): δ 1.06 (s, 6H, C5H4Me), 1.36, 1.54 (s, 3H ꢀ 2, C5H4Me),
3.54, 3.58, 3.67, 3.82, 4.04, 4.21, 4.47, 4.89 (m, 2H ꢀ 8, C5H4Me),
7.04-7.13 (m, 6H, o,p-Ph), 7.46 (m, 4H, m-Ph), 9.89 (s, 2H,
HCCH), 10.46 (d, 1H, 3JHP = 6.6 Hz, HCCP). 13C{1H} NMR
(C6D6): δ 12.6, 12.8, 13.6 (C5H4Me), 84.4, 85.9, 86.0, 86.6, 86.9,
87.9, 88.4, 88.5, 95.8, 99.2, 100.5 (C5H4Me), 127.6 (m-Ph), 127.8
(p-Ph), 134.9 (d, 2JCP = 20 Hz, o-Ph), 144.3 (1JCP = 32 Hz, ipso-
Ph), 210.5 (d, 1JPC = 98 Hz, HCCP), 215.5 (HCCH), 216.2 (d,
2JCP = 9H, HCCP). 31P{1H} NMR (C6D6): δ 51.6. IR (KBr
pellet, cm-1): 3059 (w), 2925 (s), 2898 (s), 1482 (m), 1453 (m),
1431 (m), 1371 (w), 1261 (w), 1029 (s), 855 (m), 820 (s), 792 (s),
748 (m), 700 (m).
In conclusion, the PPh2 group was successfully introduced
onto the [4Fe-4C] core. The electron-rich [4Fe-4C] core
gives rise to an extremely electron-releasing characteristic
of 2, which is estimated by the NMR parameter of the
JPSe value in the corresponding selenide 3. Ligand 2 can
perturb the electronic structure of transition-metal centers
through redox processes, which would allow switching of the
reactivity and functionality at the metal center.
Experimental Section
General Procedures. All reactions were performed under a dry
nitrogen or argon atmosphere using standard Schlenk techni-
ques. Acetonitrile and dichloromethane were distilled from
CaH2 and stored over activated molecular sieves (MS4A).
Diethyl ether and hexane were distilled from sodium benzophe-
none ketyl prior to use. [(η5-C5H4Me)4Fe4(HCCH)(HCC-Br)]-
(PF6) (1) was prepared according to the literature method.4
Other chemicals were purchased and used as received. NMR
spectra were recorded on a Bruker Avance II 400 spectrometer.
Chemical shifts are reported in δ, referenced to 1H (of residual
protons) and 13C signals of deuterated solvents as internal
standards or to the 31P signal of 85% H3PO4 as an external
standard. IR spectra were recorded on a JASCO FT/IR-410.
MS and elemental analysis were performed by the ICR Analy-
tical Laboratory, Kyoto University. Cyclic voltammetry was
carried out with a Bioanalytical System ALS-600B electroche-
mical analyzer. Measurements were made in 0.1 mol dm-3
tetrabutylammonium tetrafluoroborate (TBAB)/acetonitrile
solutions with a three-electrode system with a Pt rod working
electrode, a Pt coil auxiliary electrode, and an Ag/AgNO3
reference electrode.
Synthesis of [(η5-C5H4Me)4Fe4(HCCH)(HCC-P(Se)Ph2)]
(3). A suspension of 2 (31.8 mg, 0.0410 mmol) and selenium
powder (9.7 mg, 0.12 mmol) in dichloromethane (2 mL) was
stirred at room temperature for 1 h. Insoluble materials were
removed by filtration. Removal of volatiles from the filtrate
under vacuum gave 3 as a dark brown solid. Yield: 34.3 mg
(98%). Data of 3: Anal. Calcd for C40H41Fe4PSe: C, 56.19; H,
4.83. Found: C, 55.99; H, 5.04. Mass (FAB): m/z 856 (Mþ, 21).
1H NMR (C6D6): δ 0.88 (s, 6H, C5H4Me), 1.28, 1.39 (s, 3H ꢀ 2,
C5H4Me), 3.50, 3.70, 3.80, 3.81, 4.10, 4.21, 4.75, 5.31 (m, 2H ꢀ 8,
C5H4Me), 7.00-7.03 (m, 6H, o- and p-Ph), 7.85 (m, 4H, m-Ph),
3
9.89 (s, 2H, HCCH), 10.41 (d, 1H, JPH = 11.6 Hz, HCCP).
13C{1H} NMR (C6D6): δ 12.4, 12.7, 13.6 (C5H4Me), 85.3, 86.75,
86.82, 88.1, 88.2, 88.5, 88.9, 89.4, 97.1, 99.6, 101.0 (C5H4Me),
Synthesis of [(η5-C5H4Me)4Fe4(HCCH)(HCC-PPh2)](PF6)
([2](PF6)). Method A: To a solution of 1 (500 mg, 0.613 mmol) in
dichloromethane (30 mL) were added PPh2H (124 mg, 0.666
mmol) and NEt3 (74.0 mg, 0.731 mmol) at room temperature.
After stirring for 2 h, volatiles were removed under vacuum. The
residue was subjected to silica gel flash column chromatogra-
phy. Elution with a dichloromethane/acetonitrile (20:1) mixture
afforded a brown band. The eluate was concentrated to dryness
to give [(η5-C5H4Me)4Fe4(HCCH)(HCC-PPh2)](PF6) ([2]-
(PF6)) as a brown solid. Yield: 366 mg (65%). Method B: To a
solution of HPPh2 (110 mg, 0.592 mmol) in hexane (5 mL) was
added nBuLi (1.59 M hexane solution, 0.41 mL, 0.65 mmol) at
0 °C. After stirring at room temperature for 30 min, volatiles are
removed under reduced pressure. The resultant LiPPh2 was
suspended in acetonitrile (7 mL) and added to a solution of 1
(439 mg, 0.538 mmol) in acetonitrile (10 mL) at room tempera-
ture. After stirring for 45 min, volatiles were removed under
vacuum. The residue was subjected to silica gel flash column
chromatography. Elution with a dichloromethane/acetonitrile
(20:1) mixture afforded a brown band. The eluate was concen-
trated to dryness to give [2](PF6) as a brown solid. Yield: 228 mg
(46%). Data of [2](PF6): Anal. Calcd for C40H41F6Fe4P2: C,
52.16; H, 4.49. Found: C, 51.92; H, 4.55. Mass (FAB): m/z 776
(Mþ - PF6, 41), 591 (Mþ - PF6 - PPh2, 100). 1H NMR
(CD3CN): δ -77.6 (br, W1/2 = 63 Hz, 1H, HCC-P), -67.3
(br, W1/2 = 52 Hz, 2H, HCCH), -6.6, 0.5 (br, W1/2 = 14 Hz,
3H ꢀ 2 C5H4Me), 1.5 (br, W1/2 = 19 Hz, 6H, C5H4Me), 5.1 (br,
2
4
127.2 (d, JPC = 10 Hz, o-Ph), 129.7 (d, JPC = 3 Hz, p-Ph),
133.5 (d, 3JPC = 9 Hz, m-Ph), 138.5 (d, 1JPC = 61 Hz, ipso-Ph),
193.1 (d, 1JPC = 17 Hz, HCCP), 215.9 (HCCH), 219.4 (HCCP).
1
31P{1H} NMR (C6D6): δ 57.4 (d, JSeP = 693 Hz). IR (KBr
pellet, cm-1): 3083 (w), 2919 (m), 2278 (w), 1483 (m), 1454 (m),
1434 (m), 1371 (m), 1260 (w), 1087 (m), 1028 (m), 927 (w), 863
(m), 803 (m), 745 (m), 695 (m), 603 (w), 572 (w), 532 (m), 501 (m).
Synthesis of [(η5-C5H4Me)4Fe4(HCCH)(HCC-P(AuCl)Ph2)]
(4). [AuCl(SMe2)] (8.8 mg, 0.030 mmol) and 2 (23.1 mg, 0.0298
mmol) were dissolved in dichloromethane (1.5 mL), and the
solution was stirred at room temperature for 25 min. After
removal of volatiles under vacuum, recrystallization of the
residue from dichloromethane/hexane gave dark brown crystals
of [(η5-C5H4Me)4Fe4(HCCH)(HCC-P(AuCl)Ph2)] (4). Yield:
23.1 mg (77%). Data of 4: Anal. Calcd for C40H41AuClFe4P: C,
47.64; H, 4.10. Found: C, 47.19; H, 4.13. Mass (FAB,
m-nitrobenzyl alcohol): m/z 1007 (Mþ - 2H, 71). 1H NMR
(CD2Cl2): δ 1.03 (s, 6H, C5H4Me), 1.51, 1.59 (s, 3H ꢀ 2,
C5H4Me), 3.73, 3.84, 3.85, 4.01, 4.19, 4.28, 4.55, 4.78 (m, 2H
ꢀ 8, C5H4Me), 7.38-7.53 (m, 10H, Ph), 9.99 (s, 2H, HCCH),
3
10.30 (d, 1H, JPH = 11.1 Hz, HCCP). 13C{1H} NMR
(CD2Cl2): δ 12.3, 12.9, 13.6 (C5H4Me), 85.5, 85.9, 87.02,
87.05, 87.7, 88.4, 89.8, 97.6, 101.4, 102.1 (C5H4Me), 128.4 (d,
4
3JPC = 10 Hz, m-Ph), 130.8 (d, JPC = 2 Hz, p-Ph), 134.7 (d,
1
2JPC = 12 Hz, o-Ph), 135.2 (d, JPC = 45 Hz, ipso-Ph), 215.4
W
1/2 = 24 Hz, 4H, Ph), 5.2, 5.7, 6.5, 9.7, 10.4, 10.8, 11.7, 13.0
(HCCP), 216.7 (HCCH). The 13C NMR signal of the carbon
atom connected to the PPh2 moiety was not assigned. 31P{1H}
NMR (122 Hz, CD2Cl2): δ 62.2 (s).
(br, W1/2 = 29 Hz, 2H ꢀ 8, C5H4Me), 6.7 (br, W1/2 = 22 Hz, 4H,
Ph), 7.3 (br, W1/2 = 22 Hz, 2H, Ph). 13C{1H} NMR (CD3CN): δ
1.7, 9.3, 24.1 (C5H4Me), 64.1, 78.6, 92.2, 95.1, 96.3, 97.6, 99.6,
Synthesis of [(η5-C5H4Me)4Fe4(HCCH)(HCC-P(AuCl)Ph2)]-
(PF6) ([4](PF6)). [AuCl(SMe2)] (19.4 mg, 0.0659 mmol)
and [2](PF6) (60.8 mg, 0.0660 mmol) were dissolved in dichloro-
methane (6 mL), and the solution was stirred at room
99.9, 139.0, 139.2 (C5H4Me), 127.2, 128.3, 155.0 (Ph). Other 13
C
NMR signals were not assigned due to the line-broadening.
31P{1H} NMR (CD3CN): δ -281 (br, W1/2 = 173 Hz). IR (KBr

7058 Organometallics, Vol. 28, No. 24, 2009
Okazaki et al.
temperature for 30 min. After removal of volatiles, recrystalliza-
tion of the residue from dichloromethane/hexane gave dark
brown crystals of [(η5-C5H4Me)4Fe4(HCCH)(HCC-P(AuCl)-
Ph2)](PF6) 1/4(CH2Cl2) ([4](PF6) 1/4(CH2Cl2)). The ratio of
X-ray Structure Analysis. The X-ray diffraction study was
performed on a Rigaku Mercury CCD diffractometer with
graphite-monochromated Mo KR radiation (λ = 0.71070 A).
The intensity data were collected at 173 K and corrected for
Lorentz and polarization effects and absorption (numerical).
The structure was solved by direct methods and refined by full-
matrix least-squares on F2 against all reflections using the
program SHELXL-97. Further information is available as
CIF files in the Supporting Information.
˚
3
3
[4](PF6) and CH2Cl2 was established by 1H NMR data and
confirmed by elemental analysis. Yield: 65.3 mg (83%). Data of
[4](PF6) 1/4(CH2Cl2): Anal. Calcd for C40.5H42AuCl2F6Fe4P2:
3
C, 41.15; H, 3.56. Found: C, 41.50; H, 3.58. Mass (FAB): m/z
=
1008 (Mþ - H, 100). 1H NMR (CD3CN): δ -68.9 (br, W1/2
60 Hz, 1H, HCCP), -66.4 (br, W1/2 = 51 Hz, 2H, HCCH), -5.7,
1.5 (br, W1/2 = 10 Hz, 3H ꢀ 2, C5H4Me), 1.0 (br, W1/2 = 18 Hz,
6H, C5H4Me), 5.2 (m, 4H, o-Ph), 6.1, 7.1, 8.0, 9.5, 11.2, 12.3, 13.7,
13.8 (br, W1/2 = 21 Hz, 2H ꢀ 8, C5H4Me), 6.83 (m, 4H, m-Ph),
7.47 (m, 2H, p-Ph). 13C{1H} NMR (CD3CN): δ 8.2, 21.4
(C5H4Me), 68.7, 69.9, 92.8, 101.1, 104.7, 108.0, 117.4, 121.0
(C5H4Me), 87.0, 107.4, 149.9, 159.8 (ipso-C5H4Me or ipso-Ph),
128.1, 128.8, 131.8 (Ph). Other 13C NMR signals were not
assigned due to the line-broadening. 31P{1H} NMR (CD3CN):
δ -456 (br, W1/2 = 276 Hz). IR (KBr, cm-1): 3924 (w), 1483 (m),
1436 (m), 1374 (m), 1261 (w), 1094 (m), 1030 (m), 844 (vs),
746 (m), 700 (m), 557 (s).
Acknowledgment. This work was supported by the
Ministry of Education, Culture, Sports, Science, and
Technology of Japan (Grants-in-Aid for Scientific
Research Nos. 17750051, 19655019, 20037036, 20350027,
21655019).
Supporting Information Available: ORTEP drawing of
[4](PF6) and CIF files giving crystal data for compounds 3, 4,
and [4](PF6). This material is available free of charge via the
Internet at http://pubs.acs.org.