Distorted square planar Ni(II)-chalcogenolate carbonyl complexes [Ni(CO)(SPh(n)(SePh)(3-n)]- (n = 0, 1, 2): Relevance to the nickel site in CO dehydrogenases and [NiFeSe] hydrogenase

Full text of DOI:10.1021/ja971705c

J. Am. Chem. Soc. 1997, 119, 9299-9300
9299
of heterometallic chalcogenolate species12a,b and that fac-[Fe-
(CO)3(SePh)3]- exhibits a unique coordination behavior toward
divalent nickel ion.12 c-e Our efforts toward the preparations
of Ni(II)-selenolate and Ni(II)-mixed-chalcogenolate carbonyl
complexes providing the first example of binding of CO at a
square planar Ni(II) center surrounded by biological selenolate/
thiolate ligands exploits use of fac-[Fe(CO)3(SePh)3]- as a
selenolate ligand-transfer reagent.
Distorted Square Planar Ni(II)-Chalcogenolate
-
Carbonyl Complexes [Ni(CO)(SPh)n(SePh)3-n
]
(n ) 0, 1, 2): Relevance to the Nickel Site in CO
Dehydrogenases and [NiFeSe] Hydrogenase
Wen-Feng Liaw,*,† Yih-Chern Horng,† Der-Shiaw Ou,†
Chao-Yi Ching,† Gene-Hsiang Lee,‡ and Shie-Ming Peng§
A mixture of [CpNi(CO)]2 (0.0608 g, 0.2 mmol) and (PhSe)2
(0.062 g, 0.2 mmol) was added to fac-[PPN][Fe(CO)3(SePh)3]
(0.458 g, 0.4 mmol) in acetonitrile (or THF) solution, and the
reaction mixture was stirred under N2 at 30 °C. The reaction
mixture finally led to the isolation of dark green [PPN][Ni-
(CO)(SePh)3] precipitate (0.341 g, 83%)13 on addition of diethyl
ether and the diethyl ether-soluble green CpFe(CO)2(SePh)
(0.107 g, 80%).14 The complex [PPN][Ni(CO)(SePh)3] is
insoluble in hexane and ethyl ether and forms slightly air-
sensitive solutions in THF and CH3CN. Crystals suitable for
X-ray analysis were obtained by tetrahydrofuran/hexane diffu-
sion. The sequences of reaction given in Scheme 1 reasonably
accounts for the observation. The oxidative addition of diphenyl
diselenide across the Ni-Ni bond,15 bridge-breaking, and
Department of Chemistry, National Changhua
UniVersity of Education, Changhua 50058, Taiwan
Instrumentation Center
National Taiwan UniVersity, Taipei, Taiwan
Department of Chemistry, National
Taiwan UniVersity, Taipei 10764, Taiwan
ReceiVed May 27, 1997
The chemistry of transition metal selenolate/thiolate com-
plexes has been actively pursued, motivated primarily by
bonding diversity, perspectives of reactivity,1 and, in particular,
the relevance of such complexes (e.g., Fe-thiolate, Ni-thiolate,
and Fe-Ni-chalcogenolate complexes) to biomimetic chem-
istry.2 The structure of the [NiFeSe] hydrogenase from D.
baculatus, determined by XAS studies, revealed that the nickel
is ligated to one Se atom at 2.44 Å, one to two S/Cl atoms at
2.17 Å, and three to four N/O atoms at 2.06 Å.3 A more sulfur-
rich environment is found for nickel in the recently reported
X-ray crystal structure of [NiFe] hydrogenase isolated from D.
gigas, which indicated as well that the Ni ion in the hydrogenase
is in a binuclear metal site bridged by thiocysteines.4 In CODH,
the oxidation of CO to CO2 and acetyl-CoA synthesis from CO,
CH3 group, and CoA occur at coupled [Ni-X-Fe] centers,5
and both nickel and iron have been proposed as binding sites
of CO.6,7 Additionally, excess CO is known to inhibit activity
in both CODH and in [NiFe] hydrogenase, hence precedents
for Ni-CO binding and their spectral characteristics are
desirable.2,5 Recently, the five-coordinate Ni(I)-chalcogenolate
carbonyl complex [Ni(DAPA)(EPh)2(CO)]- (E ) S, Se)8 and
the first five-coordinate Ni(II) thiolate carbonyl complex
[Ni(PS3*)(CO)]- (PS3* ) tris(3-phenyl-2-thiophenyl)phos-
phine) were reported.9 In spite of the large number of Ni(0)
carbonyl complexes known and one series of square planar
Ni(II) carbonyls suggested,10 no example of CO bonded to
Ni(II) in a square planar geometry has been structually
characterized.11
-
displacement of a coordinated C5H5 ligand by an incoming
tridentate metallo ligand fac-[Fe(CO)3(SePh)3]- must be ac-
companied by cyclopentadienyl ligand-transfer from Ni(II) to
Fe(II),16 concomitant Fe(II)-SePh bond cleavage, and a labile
carbonyl ligand shifting from Fe(II) to Ni(II) (CpNi(CO)(SePh),
thermally unstable, converted into [CpNi(µ-SePh)]2 at room
temperature, and the addition of fac-[Fe(CO)3(SePh)3]- to
[CpNi(µ-SePh)]2 in THF led to formation of [Ni(CO)(SePh)3]-
and CpFe(CO)2(SePh)).12a These results establish that the same
stoichiometric quantities of CpFe(CO)2(SePh) are formed
concurrently with [PPN][Ni(CO)(SePh)3].
Complex [NiII(CO)(SePh)3]- exhibits a νCO IR band at 2023
cm-1 which compares well to the νCO bands of pentacoordinate
Ni(I)/Ni(II) carbonyl complexes such as [Ni(NS3tBu)(CO)][BPh4]
(2026 cm-1),17 [Ni(DAPA)(SePh)2(CO)]- (2024 cm-1),8 and
(11) Macgregor, S. A.; Lu, Z.; Eisenstein, O.; Crabtree, R. H. Inorg.
Chem. 1994, 33, 3616. (b) Baidya, N.; Olmstead, M. M.; Whitehead, J. P.;
Bagyinka, C.; Maroney, M. J.; Mascharak, P. K. Inorg. Chem. 1992, 31,
3612. (c) Miedaner, A.; Curtis, C. J.; Wander, S. A.; Goodson, P. A.;
DuBois, D. L. Organometallics 1996, 15, 5185.
(12) (a) Liaw, W. -F.; Chuang, C.-Y.; Lee, W.-Z.; Lee, C.-K.; Lee, G.-
H; Peng, S.-M. Inorg. Chem. 1996, 35, 2530. (b) Liaw, W.-F.; Lee, W.-Z.;
Wang, C.-Y.; Lee, G.-H.; Peng, S.-M. Inorg. Chem. 1997, 36, 1253. (c)
Liaw, W.-F.; Lai, C.-H.; Chiang, M.-H.; Lee, C.-K.; Lee, G.-H.; Peng, S.-
M. J. Chem. Soc., Dalton Trans. 1993, 2421. (d) Liaw, W.-F.; Chiang,
M.-H.; Liu, C.-J.; Harn, P.-J.; Liu, L.-K. Inorg. Chem. 1993, 32, 1536. (e)
Liaw, W.-F.; Chen, C.-H.; Lee, C.-M.; Lee, G.-H.; Peng, S.-M. Submitted
for publication.
Recent work in this laboratory has shown that cis-[Mn(CO)4-
(ER)2]- (E ) Se, Te; R ) phenyl, alkyl) serve as chelating
ligands and selenolate ligand-transfer reagents in the syntheses
1
† National Changhua University of Education.
(13) [PPN][Ni(CO)(SePh)3]: IR (νCO) (THF): 2023 s cm-1. H NMR
‡ Instrumentation Center, National Taiwan University.
(CD3CN): δ 7.04-7.61 (m) (Ph) ppm. 13C NMR (CD3CN): δ 134.5, 133.3,
133.2, 133.0, 130.4, 130.3, 130.2, 130.1, 129.2, 129.0, 125.7 (Ph) ppm.
Absorption spectrum (THF) [λmax, nm (ꢀ, M-1 cm-1)]: 337(16 710),
419(1979) (sh), 569(952). Anal. Calcd for C55H45ONP2Se3Ni: N, 1.28; C,
60.41; H, 4.15. Found: N, 1.34; C, 60.20; H, 4.13. The complex [PPN]-
[Ni(CO)(SePh)3] crystallized in triclinic space group P1h with a )
10.117(4) Å, b ) 15.780(4) Å, c ) 16.425(5) Å, R ) 72.50(3)°, â ) 86.78-
(3)°, γ ) 87.26(3)°, chemical formula ) C55H45ONP2NiSe3, fw ) 1093.49,
V ) 2495.5(14) Å3, Z ) 2, dcalc ) 1.455 g cm-3, λ ) 0.7107, F(000) )
1101, and T ) 298 K; final R ) 0.044 and Rw ) 0.040.
§ Department of Chemistry, National Taiwan University.
(1) Arnold, J. In Progress in Inorganic Chemistry; Karlin, K. D., Ed.;
John Wiley & Sons: New York, 1995; Vol. 43, p 353.
(2) (a) Ragsdale, S. W. In Acetogenesis; Drake, H. L., Ed.; Chapman
and Hall: New York, 1994. (b) Halcrow, M. A.; Christou, G. Chem. ReV.
1994, 94, 2421. (c) Koloweicz, A. F. Prog. Inorg. Chem. 1994, 41, 493.
(d) Moura, J. J. G.; Teixeira, M.; Moura, I.; LeGall, J. The Bioinorganic
Chemistry of Nickel; Lancaster, J. R., Ed.; VCH Publishers: New York,
1988.
1
(3) Eidsness, M. K.; Scott, R. A.; Prickril, B. C.; DerVartanian, D. V.;
LeGall, J.; Moura, I.; Moura, J. J. G.; Peck, H. D., Jr. Proc. Natl. Acad.
Sci. U.S.A. 1989, 86, 147.
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Fontecilla-Camps, J. C. Nature 1995, 373, 580.
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Soc. 1996, 118, 10429.
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W.; Lindahl, P. A.; Mu¨nck, E. J. Am. Chem. Soc. 1996, 118, 830.
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(14) (a) CpFe(CO)2(SePh): IR (ν co) (THF): 2022 s, 1974 s cm-1. H
NMR (CD3CN): δ 5.03 (s) (Cp), 7.06-7.59 (m) (Ph) ppm. 13C NMR
(CD3CN): δ 86.71 (Cp), 137.0, 129.1, 126.4 (Ph), 215.8 (CO) ppm. The
complex CpFe(CO)2(SePh) crystallized in monoclinic space group P21/c
with a ) 9.554(3) Å, b ) 11.479(3) Å, c ) 11.775(6) Å, â ) 104.58(3)°,
V ) 1249.8(8) Å3, Z ) 4, dcalc ) 1.770 gcm-3, λ ) 0.7107, F(000) ) 657,
and T ) 298 K; final R ) 0.063 and Rw ) 0.062. (b) Schermer, E. D.;
Baddley, W. H. J. Organometal. Chem. 1971, 27, 83.
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Chem. 1993, 32, 1435.
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S0002-7863(97)01705-8 CCC: $14.00 © 1997 American Chemical Society

9300 J. Am. Chem. Soc., Vol. 119, No. 39, 1997
Communications to the Editor
Figure 1. ORTEP drawing and labeling scheme of the [Ni(CO)(SePh)3]-
anion. Selected bond distances (Å) and angles (deg): Ni-Se(1),
2.349(1); Ni-Se(2), 2.293(1); Ni-Se(3), 2.309(2); Ni-C(1), 1.729-
(8); C(1)-O, 1.128(9); Se(1)-C(2), 1.928(7); Se(2)-C(8), 1.902(7);
Se(3)-C(14), 1.928(6); Se(1)-Ni-Se(2), 173.84(5); Se(1)-Ni-Se-
(3), 83.99(5); Se(1)-Ni-C(1), 87.17(23); Se(2)-Ni-Se(3), 92.79(5);
Se(2)-Ni-C(1), 96.35(23); Se(3)-Ni-C(1), 170.44(24); Ni-C(1)-
O, 177.1(7); Ni-Se(1)-C(2), 107.95(20); Ni-Se(2)-C(8),
112.30(17); Ni-Se(3)-C(14), 112.29(20).
Figure 2. ORTEP drawing and labeling scheme of the CpFe(CO)2-
(SePh). Selected bond distances (Å) and angles (deg): Fe-Se,
2.413(3); Fe-C(1), 1.731(15); Fe-C(2), 1.758(14); Fe-C(9),
2.090(14); Fe-C(10), 2.043(16); Fe-C(11), 2.073(16); Fe-C(12),
2.036(16); Fe-C(13), 2.072(14); Se-Fe-C(1), 90.3(5); Se-Fe-C(2),
91.8(5); C(1)-Fe-C(2), 94.6(6); Fe-Se-C(3), 105.8(3).
the average Fe(II)-SePh bond length of 2.459(2) Å in fac-[Fe-
(CO)3(SePh)3]- (Figure 2).12c
The reaction of [Ni(CO)(SePh)3]- with 1 equiv of (PhS)2 in
THF results in immediate formation of the extremely air-
sensitive dark green [Ni(CO)(SPh)(SePh)2]- (compared to
[Ni(CO)(SePh)3]-) in 87% yield under N2 at 25 °C.21 When
the air-sensitive [Ni(CO)(SPh)(SePh)2]- solution was exposed
to 13CO, an absorbance at 1982 cm-1 appeared within 10 min.
Reappearance of the 2028 cm-1 band on removal of the 13CO
and replacement with 12CO atmosphere demonstrated revers-
ibility of CO ligand lability of [Ni(CO)(SPh)n(SePh)3-n]- (n )
0, 1) complexes.22 In a similar fashion, [Ni(CO)(SePh)3]- was
reacted with (PhS)2 (1:2 molar ratio) in THF under a nitrogen
atmosphere, and the reaction mixture finally led to the isolation
Scheme 1
of dark green [Ni(CO)(SPh)2(SePh)]-.23,24
Such structural models as [Ni(CO)(SPh)n(SePh)3-n
[Ni(PS3*)(CO)]- (2029 cm-1).9 When a THF solution of
[NiII(CO)(SePh)3]- is purged with 13CO, the IR νCO peak at
2023 cm-1 immediately shifts to a single absorbance at 1976
cm-1. The magnitude 47 cm-1 of the isotopic shift is consistent
with the calculated position, based only on the difference in
masses between 12CO and 13CO.
-
]
(n )
0, 1, 2) may be appreciated as possibilities for intermediates in
biological reaction pathways or as structures important to CO-
inhibitory processes in Ni-containing enzymes.25 In our hands
they serve as precursors for synthetic goals of preparing Ni-
Fe heterometallics in biological-type ligation settings, and
reactivity studies of these Ni(II)-chalcogenolate carbonyl
complexes are underway.
The molecular structure of [Ni(CO)(SePh)3]- is depicted in
Figure 1. Nickel is best described as existing in a distorted
square planar coordination environment surrounded by one
carbonyl and three terminal phenylselenolates in [Ni(CO)(SePh)3]-
with Se(3)-Ni-C(1) ) 170.44(24)°, Se(1)-Ni-Se(2) )
173.84(5)°, Se(1)-Ni-Se(3) 83.99(5)°, and Se(2)-Ni-Se(3)
) 92.79(5)°. The Ni(II)-Se bond lengths range from
2.293(1) to 2.349(1) Å (average ) 2.317(2) Å). These are
shorter than the Ni(II)-Se distances reported in tetrahedral
[Ni(SePh)4]2- (Ni-Seav ) 2.401(3) Å),18 five-coordinate [Ni-
(DAPA)(SePh)2] (Ni-Seav ) 2.420(1) Å),8 and [Ni(dmp)(2,4,6-
(Me)3C6H2Se)2] (Ni-Seav ) 2.362(3) Å),19 but longer than that
observed for planar [Ni(Se(CH2)2N(Me)(CH2)2Se]2, average Ni-
(II)-Se ) 2.295(6) Å.20 The [NiII(CO)(SePh)3]- exhibits a
shorter Ni-CO distance (1.729(8) Å) than [Ni(NS3tBu)(CO)]+
(1.85(1) Å)17 and [Ni(PS3*)(CO)]- (1.75(3) Å (PS3* ) tris-
(3-phenyl-2-thiophenyl)phosphine)).9 The terminal Fe(II)-SePh
bond length of 2.413(3) Å in CpFe(CO)2(SePh) is shorter than
Acknowledgment. We thank the National Science Council (Taiwan)
for support of this work.
Supporting Information Available: Tables of crystal data and
experimental conditions for the X-ray studies, atomic coordinates and
Beq values, complete listings of bond lengths and bond angles, and
anisotropic temperature factors for [PPN][Ni(CO)(SePh)3] and CpFe-
(CO)2(SePh) (7 pages). See any current masthead page.
JA971705C
(21) [PPN][Ni(CO)(SPh)(SePh)2]: IR (νCO) (THF): 2028 s cm-1
.
(22) (a) Lai, C.-H.; Reibenspies, J. H.; Darensbourg, M. Y. Angew.
Chem., Int. Ed. Engl. 1996, 35, 2390. (b) Kumar, M.; Ragsdale, S. W. J.
Am. Chem. Soc. 1992, 114, 8713.
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1992, 114, 6587. (b) Ram, M. S.; Riordan, C. G. J. Am. Chem. Soc. 1995,
117, 2365.
(24) [PPN][Ni(CO)(SPh)2(SePh)]: IR (νCO) (THF): 2032 s cm-1
.
(18) Goldman, C, M.; Olmstead, M. M.; Mascharak, P. K. Inorg. Chem.
1996, 35, 2752.
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118, 483. (c) Bastian, N. R.; Diekert, G.; Niederhoffer, E. C.; Teo, B.-K.;
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