Templated synthesis and intact coordination of a diorganotriselenane: [RuCl2(PPh3){κ3-Se,N,N′-Se(mt Se)2}] (mtSe = selenomethimazolyl)

Article abstract of DOI:10.1021/om0608511

The reaction of [RuCl₂(PPh₃)₃] with methimazole (Hmt) under basic conditions provides the simple bis(chelate) complex [Ru(κ²-S,N-mt)₂(PPh₃) ₂], while the selenium analogue Hmt^Se provides an intact coordinated diorganotriselenane [Ru{κ³-Se,N,N′-Se(mt ^Se)₂}Ch(PPh₃)]. Bidentate mt^Se coordination is however observed in the complexes [RuR(κ²-Se,N) (CO)-(PPh₃)₂] (R = H, CH=CHC₆H ₄Me-4).

Full text of DOI:10.1021/om0608511

Organometallics 2006, 25, 5843-5846
5843
Templated Synthesis and Intact Coordination of a
Diorganotriselenane: [RuCl2(PPh3){K3-Se,N,N′-Se(mtSe)2}] (mtSe )
selenomethimazolyl)
Rian D. Dewhurst, Andrew R. Hansen, Anthony F. Hill,* and Matthew K. Smith
Research School of Chemistry, Institute of AdVanced Studies, Australian National UniVersity, Canberra,
Australian Capital Territory, Australia
ReceiVed September 18, 2006
Chart 1. (a) Diorganotriselenanes; (b)
Triselenaferrocenophane; (c)
Summary: The reaction of [RuCl2(PPh3)3] with methimazole
(Hmt) under basic conditions proVides the simple bis(chelate)
complex [Ru(κ2-S,N-mt)2(PPh3)2], while the selenium analogue
HmtSe proVides an intact coordinated diorganotriselenane [Ru-
{κ3-Se,N,N′-Se(mtSe)2}Cl2(PPh3)]. Bidentate mtSe coordination
is howeVer obserVed in the complexes [RuR(κ2-Se,N)(CO)-
(PPh3)2] (R ) H, CHdCHC6H4Me-4).
Metalladichalcaferrocenophanes (X ) S, Se; M ) Pd, Pt; L
) PPh3)2c,3
Diorganotriselenanes, RSeSeSeR, are a well-established class
of organoselenium compound,1 the coordination chemistry of
which is however essentially unexplored. The exception involves
triselenometallocenophanes,2 which in reactions with zerovalent
complexes of platinum and palladium proceed via rupture of
the CSe3C spine by analogy with Seyferth’s palladadithiafer-
rocenophane synthesis (Chart 1).3 Given that even in the absence
of transition metal reagents diorganotriselenanes can be prone
to redistribution and selenium extrusion,1 this factor alone may
have discouraged the study of the organotransition metal
chemistry of such species. We have however, inadvertently
encountered a stable example of a complex of an intact
diorganotriselenane, which we describe herein. Of particular note
is the implication that the triselenane was actually constructed
at the metal center.
metal-boron dative bonding.6 We have attributed this phenom-
enon to the geometric features of methimazolyl-derived chelates
A(mt)n, which bring the bridgehead group A into close proximity
to the metal center upon coordination, e.g., as illustrated for
the isoelectronic complexes [Rh(cod){A(mt)2}] (cod ) 1,5-
cyclooctadiene, A ) BH2, CH2+), which feature three-center,
two-electron B-H-Rh and C-H-Rh interactions.7 Thus the
complex [RuH(CO)(PPh3){HB(mt)3}] (1), a precursor to the
archetypal ruthenaboratrane [Ru(CO)(PPh3){B(mt)3}](RufB)8
(2) features κ3-H,S,S′ rather than the anticipated κ3-S,S′,S′′ borate
coordination.6b,8,9 Given that 2 arose from the reaction of [RuCl-
(R)(CO)(PPh3)2] (R ) aryl, vinyl)6a with Na[HB(mt)3] and that
[Pt(PPh3){B(mt)3}](PtfB)10 is obtained similarly from [PtCl2-
(PPh3)2] under basic conditions,6f it was of interest to ascertain
whether the reaction of [RuCl2(PPh3)3] would provide a met-
allaboratrane [Ru(PPh3)2{B(mt)3}](RufB)8 or a simple scor-
We have for some time explored the unusual proclivity of
Reglinski’s poly(methimazolyl)borate ligand HB(mt)3 (Hmt )
methimazole, mt ) methimazolyl)4,5 to enter into B-H activa-
tion processes, which ultimately lead to the formation of
“metallaboratranes”, i.e., cage compounds involving transannular
(6) (a) Hill, A. F.; Owen, G. R.; White, A. J. P.; Williams, D. J. Angew.
Chem., Int. Ed. 1999, 38, 2759. (b) Foreman, M. R. St.-J.; Hill, A. F.; Owen,
G. R.; White, A. J. P.; Williams, D. J. Organometallics 2003, 22, 4446. (c)
Foreman, M. R. St.-J.; Hill, A. F.; White, A. J. P.; Williams, D. J.
Organometallics 2004, 23, 913. (d) Foreman, M. R. St.-J.; Hill, A. F.; White,
A. J. P.; Williams, D. J. Organometallics 2004, 23, 913. (e) Crossley, I.
R.; Hill, A. F.; Willis, A. C. Organometallics 2005, 24, 1062. (f) Crossley,
I. R.; Hill, A. F. Organometallics 2004, 23, 5656. (g) Crossley, I. R.;
Foreman, M. R. St.-J.; Hill, A. F.; White, A. J. P.; Williams, D. J. Chem.
Commun. 2005, 221. (h) Crossley, I. R.; Hill, A. F.; Willis, A. C.
Organometallics 2005, 24, 1062. (i) Crossley, I. R.; Hill, A. F.; Humphrey,
E. R.; Willis, A. C. Organometallics 2005, 24, 4083. (j) Crossley, I. R.;
Hill, A. F.; Willis, A. C. Organometallics 2005, 24, 4889. (k) Crossley, I.
R.; Hill, A. F.; Willis, A. C. Organometallics 2006, 25, 289.
(7) Crossley, I. R.; Hill, A. F.; Humphrey, E. R.; Smith, M. K.
Organometallics 2006, 25, 2242.
(8) To obviate confusion that might arise as to the assignment of oxidation
number, d-configuration, and metal valency for metallaboratranes, it is
recommended that line formulas for such compounds carry the suffix
(MfB)n, where n denotes the total number of d-electrons, including the
pair involved (to some variable extent) in donation to the boron.9 In a similar
manner, describing Seyferth’s palladadithiaferrocenophane3 as (FefPd)8
circumvents such issues.
* Corresponding author. E-mail: a.hill@anu.edu.au.
(1) (a) Kharasch, N.; King, W. J. Am. Chem. Soc. 1955, 77, 931. (c)
Rheinboldt, H.; Giesbrecht, E. Chem. Ber. 1955, 88, 1. (c) McKinnon, B.
J.; De Mayo, P.; Payne, N. C.; Ruge, B. NouV. J. Chim. 1978, 2, 91. (d)
Sladky, F.; Bildstein, B.; Rieker, C.; Gieren, A.; Betz, H.; Hu¨bner, T. J.
Chem. Soc., Chem. Commun. 1985, 1800. (e) Ishii, A.; Okazaki, R.; Inamoto,
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du Mont, W. W.; Jones, P. G.; Jeske, J. Z. Anorg. Allg. Chem. 1993, 619,
1693. (h) Pridoehl, M.; Steudel, R.; Baumgart, F. Polyhedron 1993, 12,
2577. (i) Bates, C. M.; Morley, C. P. J. Organomet. Chem. 1997, 533, 193.
(j) Thaler, G.; Fimml, W.; Wurst, K.; Sladky, F. Inorg. Chim. Acta 2003,
349, 45. (k) Klapoetke, T. M.; Krumm, B.; Mayer, P. Z. Naturforsch. 2004,
59B, 547.
(2) (a) Hollands, R. E.; Osborne, A. G.; Townsend, I. Inorg. Chim. Acta
1979, 37, L541. (b) Thaler, G.; Klotz, B.; Wurst, K.; Sladky, F. J.
Organomet. Chem. 2001, 637, 745. (c) Akabori, S.; Kumagai, T.; Shirahige,
T.; Sato, S.; Kawazoe, K.; Tamura, C.; Sato, M. Organometallics 1987, 6,
526.
(3) Seyferth, D.; Hames, B. W.; Rucker, T. G.; Cowie, M.; Dickson, R.
S. Organometallics 1983, 2, 472.
(9) Hill, A. F. Organometallics 2006, 25, 4741.
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Commun. 1996, 1975.
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Armstrong, D. R. J. Chem. Soc., Dalton Trans. 1999, 2119.
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10.1021/om0608511 CCC: $33.50 © 2006 American Chemical Society
Publication on Web 11/04/2006

5844 Organometallics, Vol. 25, No. 25, 2006
Communications
or its conjugate base have been reported. We find that the
reaction of [RuH(NCMe)2(CO)(PPh3)2]BF4 with HmtSe under
basic conditions does indeed provide a selenomethimazolyl
complex [RuH(κ2-N,Se-mtSe)(CO)(PPh3)2] (4).18 In parallel with
the analogous mt complex14,19 this complex hydrometalates
ethynyl toluene under ambient conditions to provide the
organometallic derivative [Ru(CHdCHC6H4Me-4)(κ2-N,Se-mt-
Se)(CO)(PPh3)2] (5) (Scheme 1).20 Surprisingly however, the
reaction of HmtSe with [RuCl2(PPh3)3] under basic conditions
does not parallel the formation of 3. Rather a dark brown
compound was isolated in modest yield and characterized as
the novel diorganotriselenane complex [RuCl2(PPh3){κ3-Se,N,N′-
Se(mtSe)2}] (6).21 The yield of 6 could be increased (ca. 63%)
by carrying out the reaction in the presence of excess elemental
selenium (4 equiv). The molecular geometry of the inner
coordination sphere is depicted in Figure 2 and shows that the
pseudo-octahedral complex has no element of symmetry, with
two distinct mtSe environments. The respective trans influences
of the phosphine and Cl2 are reflected in the modest lengthening
(8 esd) of the Ru-N bond trans to the former. The features of
note relate to the triselenane linkage and its coordination to
Figure 1. Molecular geometry of 3 in a crystal (50% displacement
ellipsoids, phenyl groups and hydrogen atoms omitted). Selected
bond distances (Å) and angles (deg): Ru1-N211 2.141(3), Ru1-
N111 2.187(3), Ru1-P1 2.2833(8), Ru1-P2 2.3057(9), Ru1-S111
2.4615(9), Ru1-S211 2.4918(8), S111-C111 1.731(3), N111-
C111 1.325(4), C111-N112 1.357(4), S211-C211 1.725(3),
N211-C211 1.332(4), C211-N212 1.343(4), P1-Ru1-P2 101.69-
(3), N111-Ru1-S111 67.90(7), P1-Ru1-S111 94.18(3), P2-
Ru1-S111 103.51(3), N211-Ru1-S211 67.57(8), N111-Ru1-
S211 95.95(7), P1-Ru1-S211 98.56(3), P2-Ru1-S211 97.80(3),
S111-Ru1-S211 152.36(3), C111-S111-Ru1 78.12(10), C111-
N111-Ru1 97.56(19), N111-C111-N112 111.6(3), N111-C111-
S111 116.4(2), N112-C111-S111 131.9(2), C211-S211-Ru1
77.21(11), C211-N211-Ru1 99.3(2), C212-N211-Ru1 153.2-
(2), N211-C211-N212 111.0(3), N211-C211-S211 115.4(2),
N212-C211-S211 133.6(3).
(17) (a) Wazeer, M. I. M.; Isab, A. A. Spectrochim. Acta, Part A 2005,
62A, 880. (b) Al-Amri, A.-H. D.; Fettouhi, M.; Wazeer, M. I. M.; Isab, A.
A. Inorg. Chem. Commun. 2005, 8, 1109. (c) Wazeer, M. I. M.; Isab, A.
A.; Ahmad, S. J. Coord. Chem. 2005, 58, 391. (d) Isab, A. A.; Ahmad, S.;
Arnold, A. P. Trans. Met. Chem. 2004, 29, 870. (e) Ahmad, S.; Isab, A.
A.; Arnold, A. P. J. Coord. Chem. 2003, 56, 539. (f) Ahmad, S.; Isab, A.
A.; Al-Arfaj, A. R.; Arnold, A. P. Polyhedron 2002, 21, 2099. (g) Williams,
D. J.; White, K. M.; Van, Derveer, D.; Wilkinson, A. P. Inorg. Chem.
Commun. 2002, 5, 124. (h) Weiss, R.; Kraut, N.; Hampel, F. J. Organomet.
Chem. 2001, 473, 617. (i) Blake, A. J.; Casabo, J.; Devillanova, F. A.;
Escriche, L.; Garau, A.; Isaia, F.; Lippolis, V.; Kivekas, R.; Muns, V.;
Schroder, M.; Sillanpia, R.; Verani, G. J. Chem. Soc., Dalton Trans. 1999,
1085. (j) Williams, D. J.; Jones, T. A.; Rice, E. D.; Davis, K. J.; Ritchie,
J. A.; Pennington, W. T.; Schimek, G. L. Acta Crystallogr. Sect. C 1997,
C53, 837. (k) Kuhn, N.; Fawzi, R.; Kratz, T.; Steimann, M.; Henkel, G.
Phosphorus Sulfur Silicon Rel. Elem. 1996, 108, 107.
pionate derivative [RuCl(PPh3)2{HB(mt)3}] analogous to the
synthetically versatile complex [RuCl(PPh3)2{HB(pz)3}] (pz )
pyrazolyl).10 In practice, neither occurs, but, rather, fragmenta-
tion of the pro-ligand occurs to provide, inter alia, traces of the
simple bis(chelate) complex [Ru(mt)2(PPh3)2] (3).11,12 Methi-
mazolyl complexes of ruthenium have recently received atten-
tion,13,14 and 3 provides a simpler analogue of the previously
reported complex [Ru(mt)2{κ2-P,P′-MeC(CH2PPh2)3}].13 Figure
1 depicts the inner coordination sphere geometry of 3, which
however calls for little comment, with metrical parameters for
the chelates falling within expected norms for bidentate mt
coordination.12-15
(18) 4: [RuH(NCMe)2(CO)(PPh3)2]BF4 (250 mg, 0.31 mmol), HmtSe (50
mg, 0.31 mmol), and DBU (200 mg, 1.31 mmol) in CH2Cl2 (100 mL) were
stirred anaerobically for 48 h, diluted with ethanol (100 mL), and slowly
concentrated (ca. 50 mL) to provide pale orange crystals. Recrystallized
(CH2Cl2/EtOH) yield 147 mg (59%). Anal. Found: C, 60.01; H, 4.73; N,
3.60. Calcd for C41H36N2OP2RuSe: C, 60.44; H, 4.45; N, 3.44. IR
(Nujol): 1962w (νRuH), 1899vs (νCO) cm-1. NMR (CDCl3, 25 °C) 1H: δH
3
The isolation of 3 suggested the possible extension to the
selenium analogue of methimazole (HmtSe).16 While the coor-
dination chemistry of saturated cyclic selenoureas is well-
developed,17 no complexes of the unsaturated heterocycle HmtSe
7.70-7.22 (m, 30 H, C6H5), 5.74, 5.49 (d × 2, 1 H × 2, NCHdCH, JHH
2
) 1.5), 2.70 (s, 3H, NCH3), -12.87 (t, 1 H, JPH ) 19.2 Hz, RuH). 31P-
{1H}: δP 49.79.
(19) The complex [RuH(mt)(CO)(PPh3)2] displays a rich chemistry
derived from both the reactivity of the hydride ligand and the hemilability
(κ2-κ1) of the mt ligand: Foreman, M. R. St.-J.; Hill, A. F.; Smith, M. K.
Manuscript in preparation.
(11) 3: This compound was only ever obtained in trace amounts sufficient
for crystallographic characterization. Crystal Data for 3: C44H40N4P2RuS2,
Mw ) 851.93 gmol-1, monoclinic, P21/a, a ) 18.5682(6) Å, b ) 10.8947-
(4) Å, c ) 19.3594(8) Å, â ) 97.332(1)°, V ) 3883.9 Å3, Z ) 4, T )
(20) 5: Ethynyltoluene (100 mg, 0.86 mmol) and 4 (70 mg, 0.086 mmol)
in toluene (5 mL) were stirred for 18 h and then diluted with methanol (30
mL) to precipitate the product. Recrystallized yield (acetone/Et2O): 29 mg
(47%). Anal. Found: C, 64.04; H, 4.61; N, 3.28. Calcd for C50H44N2OP2-
RuSe: C, 64.51; H, 4.76; N, 3.01. IR (Nujol): 1905vs (νCO) cm-1. NMR
(CDCl3, 25 °C) 1H: δH 7.83 (dt, 1 H, 3JHH ) 17.1, 3JPH not resolved, RuCH),
200(2) K, orange prsim, Dc ) 1.457 Mg m-3, µ(Mo KR) ) 0.632 mm-1
,
7924 independent absorption-corrected reflections, R ) 0.0423, Rw ) 0.0993
[6022 reflections with I > 2σ(I), 2θ < 52.74°], 480 parameters; CCDC
620515.
7.64, 7.46, 7.23 (m × 3, 30 H, C6H5), 6.82, 6.36 (d × 2, 2 H × 2, 3JHH
)
)
(12) We have on numerous occasions encountered the cleavage of mt
groups from the salts Na[H2B(mt)2], Na[HB(mt)3], e.g.: (a) Hill, A. F.;
Smith, M. K. Chem. Commun. 2005, 1920. (b) Hill, A. F.; Smith, M. K.
Dalton Trans. 2006, 28.
(13) Landgrafe, C.; Sheldrick, W. S.; Sudfeld, M. Eur. J. Inorg. Chem.
1998, 407.
(14) Wilton-Ely, J. D. E. T. Honarkhah, S. J.; Wang, M.; Tocher, D. A.;
Slawin, A. M. Z. Dalton Trans. 2005, 1930.
(15) (a) Cooper, D. A.; Rettig, S. J.; Storr, A.; Trotter, J. Can. J. Chem.
1986, 64, 1643. (b) Brandt, K.; Sheldrick, W. S. Inorg. Chim. Acta 1998,
267, 39. (c) Basumallick, L.; DeBeer,; George, S.; Randall, D. W.; Hedman,
B.; Hodgson, K. O.; Fujisawa, K.; Solomon, E. I. Inorg. Chim. Acta 2002,
337, 357.
(16) (a) Guziec, L. J.; Guziec, F. S., Jr. J. Org. Chem. 1994, 59, 4691.
(b) Taurog, A.; Dorris, M. L.; Guziec, L. J.; Guziec, F. S., Jr. Biochem.
Pharm. 1994, 48, 1447. (c) Roy, G.; Nethaji, M.; Mugesh, G. J. Am. Chem.
Soc. 2004, 126, 2712. (d) Roy, G.; Nethaji, M.; Mugesh, G. J. Am. Chem.
Soc. 2005, 127, 15207. (e) Landry, V. K.; Minoura, M.; Pang, K.; Buccella,
D.; Kelly, B. V.; Parkin, G. J. Am. Chem. Soc. 2006, 128, 12490.
7.4, C6H4), 6.27, 5.80 (s br × 2, 1 H × 2, NCHCH), 5.85 (d, 1 H, 3JHH
16.8, RuCHdCH), 2.51 (s, 3 H, NCH3), 2.22 (s, 3 H, CCH3). 31P{1H}: δP
43.02.
(21) 6: [RuCl2(PPh3)3] (261 mg, 0.27 mmol), HmtSe (87 mg, 0.55 mmol),
Na2CO3 (51 mg, 0.48 mmol), and gray selenium (80 mg, 1.01 g-atom) were
stirred anaerobically in CH2Cl2 (50 mL) for 48 h, filtered through
diatomaceous earth, concentrated to ca. 20 mL, layered with light petroleum,
and cooled to -20 °C overnight to provide black crystals. Yield: 142 mg
(63%). Anal. Found: C, 34.85; H, 2.97; N, 5.72. Calcd for C26H25N4PCl2-
1
RuSe3‚CH2Cl2: C, 35.24; H, 3.18; N, 6.09. NMR (CDCl3, 25 °C) H: δH
3
8,15 (s br, 1 H, NCHdCH) 7.22 (d, 1 H, JHH ) 2.1, NCHdCH), 6.91 (s
br, 1 H, NCHdCH), 6.39 (d, 1 H, 3JHH ) 1.5 Hz, NCHdCH), 7.86-7.18
(m, 15 H, C6H5), 3.64, 3.43 (s × 2, 3H × 2, NCH3). 31P{1H}: δP 34.22.
Crystal data for 6: C26H25N4PCl2Se3Ru‚2CH2Cl2, Mw ) 1003.17, mono-
clinic, P21/n, a ) 11.579(2) Å, b )17.835(4) Å, c ) 17.212(3) Å, â )
101.30(3)°, V ) 3485.6(12) Å3, Z ) 4, T ) 200(2) K, black prism, Dc )
1.912 Mg m-3, µ(Mo KR) ) 4.116 mm-1, 6141 independent absorption-
corrected reflections, R1 ) 0.049, wR2 ) 0.138 [6141 reflections with I >
2σ(I), 2θ < 50.1°], 390 parameters; CCDC 620516.

Communications
Organometallics, Vol. 25, No. 25, 2006 5845
Scheme 1. Synthesis of Methimazolyl, Selenomethimazolyl,
Chart 2
and Triselenane Complexes (L ) PPh3)a
Scheme 2. Possible Decomposition Routes for HmtSe
closest point of comparison is provided by the recently reported
bis(4-(phenylamino)quinazolin-2-yl)triselenane (8, see Chart
2).23 Assuming that the disparity in imidazolyl and quinazolinyl
heterocyclic substituents contributes only a modest perturbation,
the primary differences between the free and coordinated CSe3C
linkage involve elongations in the Se-Se bond lengths (6:
2.4311(11), 2.4161(11) Å vs 8: 2.324 Å) and C-Se-Se bond
angles (6: 91.9(2)°, 93.3(2)° vs 8: 102.9°), with the angles at
the unique selenium being comparable (6: 104.44(4)° vs 8:
103.54°). These variations are most likely simple corollaries of
the constraints of chelation, although retrodonation into the σ*-
(SeSe) orbital(s) could contribute to the significant lengthening
of the Se-Se bonds. This interpretation, i.e., dπfσ* retrodo-
nation, is consistent with the comparative shortening (11 esd)
of the π-donor Ru-Cl1 bond trans to Se1, relative to that trans
to N21.
a (i) RuCl2L3; (ii) RuCl2L3, Na2CO3, Se; (iii) [RuHCl(CO)L3] or
[RuH(NCMe)2(CO)L2]BF4, DBU; (iv) HCtCR (R ) C6H4Me-4).
The origin of the third selenium atom of the triselenane
ligand, in the absence of added selenium, is of note given the
well-established activation of chalcogens by N-alkylimidazoles.24
We might speculate that an equilibrium could operate, unde-
tected, relating HmtSe to the free N-heterocyclic carbene (NHC)
and elemental selenium. Were the liberated selenium to be
consumed, the NHC would simply tautomerize to N-methylimi-
dazole (Scheme 2). The reverse of this reaction could thus
account for the activating effect of N-methylimidazole on
elemental selenium. It should be noted that ruthenium has a
long tradition of effecting imidazole/imidazolylidene tautom-
erism.25 Under the mild conditions in which 6 is formed, the
combination of elemental selenium with either HmtSe or (mtSe)2
does not appear to lead to the formation of the free triselenane
(excess selenium is present during the synthesis of HmtSe), i.e.,
the metal plays a pivotal role in either the templating or the
trapping of the triselenane. An alternative interpretation is that
the metal plays a more intimate role in the activation of the
CdSe bond of HmtSe, given that the reverse reaction, i.e.,
addition of elemental selenium to a carbene complex has
Figure 2. Molecular geometry of 6 in a crystal of 6‚(CH2Cl2)2
(50% displacement ellipsoids, phenyl groups and hydrogen atoms
omitted). Selected bond distances (Å) and angles (deg): Ru1-N21
2.062(6), Ru1-N11 2.112(5), Ru1-Se1 2.2998(10), Ru1-P1
2.3333(18), Ru1-Cl1 2.4241(18), Ru1-Cl2 2.4439(17), Se1-Se21
2.4161(11), Se1-Se11 2.4311(11), Se11-C11 1.879(7), Se21-
C21 1.876(8), N21-Ru1-N11 83.7(2), N21-Ru1-Se1 91.14(16),
N11-Ru1-Se1 88.71(17), N21-Ru1-P1 92.00(16), Se1-Ru1-
P1 94.82(5), N21-Ru1-Cl1 91.23(17), N11-Ru1-Cl1 90.15(17),
P1-Ru1-Cl1 86.51(6), Se1-Ru1-Cl2 86.86(5), P1-Ru1-Cl2
95.49(6), Cl1-Ru1-Cl2 90.61(6), Ru1-Se1-Se21 102.73(4),
Ru1-Se1-Se11 101.82(4), Se21-Se1-Se11 104.44(4), C11-
Se11-Se1 91.9(2), C21-Se21-Se1 93.3(2).
(23) Atanassov, P. K.; Linden, A.; Heimgartner, H. HelV. Chim. Acta
2004, 87, 187.
(24) (a) Rauchfuss, T. B. Inorg. Chem. 2004, 43, 14. (b) Rauchfuss, T.
B.; Dev, S.; Wilson, S. R. Inorg. Chem. 1992, 31, 154. (c) Dev, S.; Ramli,
E.; Rauchfuss, T. B.; Wilson, S. R. Inorg. Chem. 1991, 30, 2514. (d) Ramli,
E.; Rauchfuss, T. B.; Stern, C. L. J. Am. Chem. Soc. 1990, 112, 4043. (e)
Dev, S.; Ramli, E.; Rauchfuss, T. B.; Stern, C. L. J. Am. Chem. Soc. 1990,
112, 6385.
(25) (a) Sundberg, R. J.; Shepherd, R. E.; Taube, H. J. Am. Chem. Soc.
1972, 94, 6558. (b) Sundberg, R. J.; Gupta, G. Bioinorg. Chem. 1973, 3,
39. (c) Sundberg, R. J.; Bryan, R. F.; Taylor, I. F., Jr.; Taube, H. J. Am.
Chem. Soc. 1974, 96, 381. (d) Tweedle, M. F.; Taube, H. Inorg. Chem.
1982, 21, 3361.
ruthenium. The Ru-Se1 separation of 2.2998(10) Å is signifi-
cantly shorter than typical values for selenoether coordination
to octahedral ruthenium(II) (2.40-2.50 Å, mean 2.46 Å).22
Although the free molecule Se(mtSe)2 “7” is unknown, the
(22) Cambridge Crystallographic Data Centre, Conquest, May 2006
release.

5846 Organometallics, Vol. 25, No. 25, 2006
Communications
precedent,26 as does the metal-mediated transfer of selenium
between isoselenocyanates and carbene27 or carbyne28 ligands.
Furthermore, the spontaneous extrusion of tellurium from a
SCTe complex has been noted.29 Finally, thioureas have been
shown to serve as carbene precursors in low-valent ruthenium
chemistry via CdS bond cleavage.30
To conclude, the first complex of an intact neutral diorga-
notriselenane Se(mtSe)2 has been isolated from a reaction that
appears to involve metal-mediated triselenane assembly. The
mechanism of formation remains obscure; however the metal
center is necessary. Furthermore, the first complexes of the
conjugate base mtSe have been isolated, allowing a demonstra-
tion that the bidentate coordination mode is hemilabile, allowing
alkyne hydrometalation to occur with an otherwise coordina-
tively saturated complex.
(26) (a) Hill, A. F.; Roper, W. R.; Waters, J. M.; Wright, A. F. J. Am.
Chem. Soc. 1983, 105, 5939. (b) Fischer, H.; Stumpf, R.; Roth, G. AdV.
Organomet. Chem. 1998, 43, 125.
(27) Fischer, H.; Zeuner, S. Z. Naturforsch. 1983, 38b, 1365.
(28) Caldwell, L. M.; Hill, A. F.; Willis, A. C. Chem. Commun. 2005,
2615.
(29) Herberhold, M.; Hill, A. F.; McAuley, N.; Roper, W. R. J.
Organomet. Chem. 1986, 310, 95.
(30) Su¨ss-Fink, G. In Transition Metal Carbyne Complexes; NATO ASI
Series, C393; Kluwer Academic Publishers: Dordrecht, 1993; p 151.
Supporting Information Available: Crystallographic data in
CIF format for 3 (CCDC 620515) and 6 (CCDC 620516). This
material is available free of charge via the Internet at http://
pubs.acs.org.
OM0608511