Copper complexes with (2,7-Di-tert-butylfluoren-9-ylidene) methanedithiolate: Oxidatively promoted dithioate condensation

Article abstract of DOI:10.1002/ejic.200500613

The reaction of [Cu(NCMe)₄]PF₆ with piperidinium 2,7-di-tert-butyl-9H-fluorene-9-carbodithioate (pipH)[S₂C(tBu-Hfy)] (1; tBu-Hfy = 2,7-di-tert-butylfluoren-9-yl), affords [Cu_n{S ₂C(tBu-Hfy)}_n] (2), which reacts with various P ligands to give [Cu{S₂C(tBu-Hfy)}L₂] [L = PPh₃ (3a), PCy₃ (3b), PiPr₃ (3d); L₂ = 1,1′-bis(diphenylphosphanyl)ferrocene (dppf, 3c), bis(diphenylphosphanyl) methane (dppm, 3e)]. Compounds 3a-c react with atmospheric oxygen and moisture in the presence of NEt₃ to give the dinuclear complexes [Cu ₂{[SC=(tBu-fy)]₂S}L₂] [tBu-fy = 2,7-di-tert-butylfluoren-9-ylidene; L = PPh₃ (4a), PCy₃ (4b); L₂ = dppf (4c)], which contain a new dithiolato ligand formally resulting from the condensation of two dithioato ligands with loss of a sulfide ion and two protons. Neutral Cu^I dithiolate complexes of the type [Cu₄{S₂C=(tBu-fy)}₂L₄] [S ₂C=(tBu-fy) = [2,7-di-tert-butylfluoren-9-ylidene)methanedithiolate; L = PPh₃ (5a), P(C₆H₄OMe-p)₃ (5b), PiPr₃ (5d) or L₂ = dppf (5c)] were obtained by treating 1 with [Cu(NCMe)₄]PF₆, the corresponding phosphane, and piperidine in a 1:2:2:1 molar ratio. The reaction of 1 with Cu(ClO ₄)₂·6H₂O and (Pr₄N)OH in a 2:1:2 molar ratio gives the Cu^II complex (Pr₄N) ₂[Cu{S₂C=(tBu-fy)}₂] [(Pr₄N) ₂6], which readily oxidizes to the Cu^III complex Pr ₄N[Cu{S₂C=(tBu-fy)}₂] (Pr₄N7) in the presence of atmospheric oxygen and moisture. The salt PPN7 [PPN⁺ = (Ph₃P)₂N⁺] was obtained from 1, CuCl ₂·2H₂O, PPNCl, and piperidine in a 2:1:1:2 molar ratio under aerobic conditions. The crystal structures of 3a, 3c·CH ₂Cl₂, 4a·4Me₂CO, and 4c·CH ₂Cl₂ have been determined by X-ray diffraction studies. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Full text of DOI:10.1002/ejic.200500613

FULL PAPER
DOI: 10.1002/ejic.200500613
Copper Complexes with (2,7-Di-tert-butylfluoren-9-ylidene)methanedithiolate:
Oxidatively Promoted Dithioate Condensation[‡]
José Vicente,[a] Pablo González-Herrero,*[a] Yolanda García-Sánchez,[a] Peter G. Jones,[b]
and Delia Bautista[c]
Keywords: Copper / Dithiolates / Phosphane ligands / S ligands
The reaction of [Cu(NCMe)4]PF6 with piperidinium 2,7-di-
tert-butyl-9H-fluorene-9-carbodithioate (pipH)[S2C(tBu-
Hfy)] (1; tBu-Hfy 2,7-di-tert-butylfluoren-9-yl), affords
P(C6H4OMe-p)3 (5b), PiPr3 (5d) or L2 = dppf (5c)] were ob-
tained by treating 1 with [Cu(NCMe)4]PF6, the correspond-
ing phosphane, and piperidine in a 1:2:2:1 molar ratio. The
reaction of 1 with Cu(ClO4)2·6H2O and (Pr4N)OH in a 2:1:2
molar ratio gives the CuII complex (Pr4N)2[Cu{S2C=(tBu-
fy)}2] [(Pr4N)26], which readily oxidizes to the CuIII complex
Pr4N[Cu{S2C=(tBu-fy)}2] (Pr4N7) in the presence of atmo-
=
[Cun{S2C(tBu-Hfy)}n] (2), which reacts with various P ligands
to give [Cu{S2C(tBu-Hfy)}L2] [L = PPh3 (3a), PCy3 (3b), PiPr3
(3d); L2 = 1,1Ј-bis(diphenylphosphanyl)ferrocene (dppf, 3c),
bis(diphenylphosphanyl)methane (dppm, 3e)]. Compounds
3a–c react with atmospheric oxygen and moisture in the pres-
ence of NEt3 to give the dinuclear complexes [Cu2{[SC=(tBu-
fy)]2S}L2] [tBu-fy = 2,7-di-tert-butylfluoren-9-ylidene; L =
PPh3 (4a), PCy3 (4b); L2 = dppf (4c)], which contain a new
dithiolato ligand formally resulting from the condensation of
two dithioato ligands with loss of a sulfide ion and two pro-
tons. Neutral CuI dithiolate complexes of the type
spheric oxygen and moisture. The salt PPN7 [PPN+
=
(Ph3P)2N+] was obtained from 1, CuCl2·2H2O, PPNCl, and pi-
peridine in a 2:1:1:2 molar ratio under aerobic conditions.
The crystal structures of 3a, 3c·CH2Cl2, 4a·4Me2CO, and
4c·CH2Cl2 have been determined by X-ray diffraction stud-
ies.
[Cu4{S2C=(tBu-fy)}2L4] [S2C=(tBu-fy)
fluoren-9-ylidene)methanedithiolate;
=
L
[2,7-di-tert-butyl-
PPh3 (5a),
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
=
industrial applications as antioxidant additives for lubricant
oils.[12–20] Previously described 1,1-ethylenedithiolates that
have been used for the preparation of copper complexes are
limited to those with X = Y = CN (i-mnt), CO2R [R =
Me (dmd), Et (ded), tBu (tBu-ded)] and X = CN and Y =
P(O)(OEt)2 (cpdt). The anionic CuI clusters [Cu8-
Introduction
The importance of copper complexes and clusters with
thiolato ligands is associated with their use as models for
the understanding of the structure, bonding, and function
of the active sites of copper–sulfur enzymes and pro-
teins,[1–6] which perform crucial functions such as electron-
transfer and dioxygen transport to redox systems and cop-
per transport and delivery.[7–11] Among the variety of sulfur
ligands employed for the synthesis of copper complexes,
1,1-ethylenedithiolates (XYC=CS22–) and related dithio li-
gands have received special attention because of their ability
to form high-nuclearity clusters, some of which have found
(i-mnt)6]4–,[12,13,19]
[Cu8(ded)6]4–,[14]
and
[Cu8(tBu-
ded)6]4–[15,16] stand out as the best-studied 1,1-ethylenedithiol-
ato complexes of copper, and theoretical calculations have
been carried out in order to understand the bonding in the
Cu8S12 core.[21,22] The tetranuclear cluster [Cu4(i-mnt)4]4–
has been obtained from the reaction of the sulfur-rich dithi-
olato cluster [Cu6{S3C=C(CN)2}6]6– with triphenylphos-
phane.[19] Clusters of higher nuclearities have been obtained
by protonation of [Cu8(ded)6]4– and [Cu8(tBu-ded)6]4–.[15,16]
A series of clusters of CuI with the cpdt ligand and bis(di-
phenylphosphanyl)methane (dppm) has also been prepared
from the reaction between [Cu2(dppm)2(NCMe)2](PF6)2
and K2cpdt.[23] The CuII complexes are represented by the
[‡] (Fluoren-9-ylidene)methanedithiolato Complexes, 3. Part 1:
Ref.[28] Part 2: Ref.[29]
[a] Grupo de Química Organometálica, Departamento de Química
Inorgánica, Facultad de Química, Universidad de Murcia,
Apdo. 4021, 30071 Murcia, Spain
E-mail: jvs1@um.es; pgh@um.es
URL: http://www.um.es/gqo
[b] Institut für Anorganische und Analytische Chemie, Technische mononuclear species [Cu(i-mnt)2]2–,[12,24] [Cu(ded)2]2–,[25,26]
and [Cu(i-mnt)(N–N)] (N–N = 1,2-ethanediamines).[27] The
Universität Braunschweig,
Postfach 3329, 38023 Braunschweig, Germany
CuIII complex [Cu(ded)2]– has also been prepared by the
E-mail: p.jones@tu-bs.de
oxidation of [Cu(ded)2]2– with H2O2, I2, or Cu2+ ions.[25,26]
[c] SACE, Universidad de Murcia,
Apdo. 4021, 30071 Murcia, Spain
Part of our recent research in this field has been devoted
to the coordination chemistry of the (fluoren-9-ylidene)me-
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
Eur. J. Inorg. Chem. 2006, 115–126
© 2006 Wiley-VCH Verlag GmbH & Co. KgaA, Weinheim 115

J. Vicente, P. González-Herrero, Y. García-Sánchez, P. G. Jones, D. Bautista
FULL PAPER
thanedithiolato ligand and its 2,7-disubstituted derivatives. dark brown complex [Cun{S2C(tBu-Hfy)}n] (2; Scheme 2),
These ligands have revealed remarkable differences with re- which precipitated in almost quantitative yield. Complex 2
spect to the previously used 1,1-ethylenedithiolates; these is scarcely soluble in most organic solvents and all attempts
differences are largely attributable to the absence of strongly to grow crystals suitable for X ray diffraction studies were
1
electron-withdrawing substituents and affect the photo- unsuccessful. Its H NMR spectrum displays only one set
physical properties and redox behavior of their metal com- of signals for the dithioato ligand, suggesting a highly sym-
plexes.[28,29] Given the multiple coordination possibilities metrical oligomeric structure. A tetrameric structure has
and stoichiometries observed for copper/dithiolate systems, been found for the related copper() dithioate
we thought it of interest to carry out an initial exploration [Cu4(S2CC6H4Me-p)4][30] (Figure 1, a). Compound 2 was
of the chemistry of copper complexes with (2,7-di-tert-bu-
2–
tylfluoren-9-ylidene)methanedithiolate [(tBu-fy)=CS2 (I)
Scheme 1], and to study the effects of the strongly electron-
donating character of this ligand on their structures and
reactivity. In this paper, we describe the preparation of a
series of CuI complexes with 2,7-di-tert-butyl-9H-fluorene-
–
9-carbodithioate [(tBu-Hfy)CS2 (II), the protonated pre-
cursor of I] obtained from the piperidinium salt
(pipH)[(tBu-Hfy)CS2] (1), which, upon deprotonation in
the presence of an oxidizing agent, afford dinuclear com-
plexes with the new ligand S[(tBu-fy)=CS]22– (III), formally
resulting from the condensation of two dithiolates with loss
of a sulfide ion and two protons. The direct syntheses of
CuI, CuII, and CuIII complexes containing the (tBu-
2–
fy)=CS2 ligand from 1 and suitable copper precursors are
reported.
Scheme 1.
Results and Discussion
–
Copper(
I
) Complexes with the (tBu-Hfy)CS2 Ligand
The previously described metal complexes with the (flu-
oren-9-yliden)methanedithiolato ligand and its 2,7-disubsti-
tuted analogs were obtained by treating appropriate metal
precursors with the corresponding piperidinium fluorene-9-
carbodithioate in the presence of a base. The deprotonation
of the dithiolato ligand to form the corresponding dithiol-
ate takes place after its coordination to the metal center,
which increases the acidity of the H9 atom on the fluoren-
9-yl moiety. In some cases, dithioato complexes have been
obtained when the reactions are carried out in the absence
of a base.[28] The synthesis of CuI complexes with (tBu-Hfy)-
CS2– was undertaken in order to use them as precursors for
Scheme 2. (i) [Cu(NCMe)4]PF6; (ii) 2L; (iii) NEt3, O2 (air) or 1/2
1,4-benzoquinone; (iv) [Cu(NCMe)4]PF6, 2L, pip; (v) 1/2
Cu(ClO4)2·6H2O, (Pr4N)OH or 1/2 CuCl2, PPNCl, pip; (vi) O2 (air).
2
the preparation of complexes with the dithiolato ligand
2–
(tBu-fy)CS2
.
The reaction of the piperidinium dithioate 1 with
[Cu(NCMe)4]PF6 in a 1:1 molar ratio in MeCN gave the and the Cu4S4P8 core in [Cu4(cpdt)2(dppm)4] (b).
Figure 1. Structures of the Cu4S8 core in [Cu4(S2CC6H4Me-p)4] (a)
116
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Copper Complexes with (2,7-Di-tert-butylfluoren-9-ylidene)methanedithiolate
FULL PAPER
employed as starting material for the preparation of the of the formation of considerable amounts of the dithiolato
series of complexes [Cu{S2C(tBu-Hfy)}L2] with L = PPh3 complex [Cu4{S2C=(tBu-fy)}2(dppf)2] (5c; see below). Un-
(3a), PCy3 (3b), PiPr3 (3d), or L2 = dppf (3c), dppm (3e). der the same conditions, compound 2 or the dppm deriva-
The products were obtained as salmon-pink or orange sol- tive 3e did not give products of definite composition, while
ids from the reactions of 2 with the corresponding phos- in the case of the PiPr3 derivative 3d a mixture that con-
phane (1:2) or diphosphane (1:1) and isolated in moderate tained the corresponding dithiolato complex 5d as the main
to high yields.
component was obtained.
A possible reaction path leading to the formation of 4a–
c is outlined in Scheme 3. It is very likely that in the initial
steps the deprotonation and oxidation of the dithioato com-
plexes 3a–c to give a CuII intermediate (A) take place, which
would account for the green color of the initial reaction
mixtures. This species can be considered an oxidized analog
Deprotonation and Oxidation of Dithioato Complexes.
Dithiolate Condensation
–
The deprotonation of the dithioato ligand (tBu-Hfy)CS2
in complexes 2 and 3a–e was attempted by using NEt3 as of the reported CuI complex [Cu(i-mnt)(PR3)2]–.[31] It is
the base. The expected results of these reactions included well known that the combination of CuII with thiolates usu-
the formation of anionic clusters. In the case of 3a–e, an- ally results in reduction to CuI and formation of disul-
ionic complexes of the type [Cu{S2C=(tBu-fy)}(PR3)2]– fides.[10,32,33] Such a process would cause intermediate A to
were expected as the primary products, since an analogous dimerize and form a disulfide-bridged dinuclear species
mononuclear complex with the i-mnt ligand has been de- such as B, which would subsequently undergo sulfur ab-
scribed.[31] However, complexes 2 and 3a–e were recovered straction by one of the phosphanes to give the final monos-
unchanged after treatment with NEt3 in MeCN or THF ulfide-bridged dithiolate. Tetraalkylthiuram disulfides
under an inert atmosphere. A different, unexpected result R2NC(S)SSC(S)NR2 have been reported to undergo a sim-
was obtained when the reactions were carried out in the ilar reaction when treated with CuI halides in the presence
presence of atmospheric oxygen and moisture. Thus, under of PPh3, which leads to the formation of complexes con-
these conditions, treatment of 3a with NEt3 in a 1:1 molar taining the corresponding monosulfide R2NC(S)SC(S)-
ratio in MeCN led to the gradual formation of a green solu- NR2.[34] The formation of the condensed ligand in 4a–c is
tion from which a yellowish orange solid precipitated after also related to the well-established reactions of organic di-
4 h. The X-ray structure analysis of a single crystal of this sulfides with phosphanes, which afford thioethers and phos-
product revealed the formation of the dinuclear complex phane sulfide, although they usually require more vigorous
[Cu2{[SC=(tBu-fy)]2S}(PPh3)2] (4a), which contains only reaction conditions, such as refluxing in high boiling point
one PPh3 per Cu and a new dithiolato ligand that formally solvents.[35–37]
results from the condensation of two (tBu-Hfy)CS2– ligands
with loss of a sulfide ion and two protons (Scheme 2). The
yield of 4a was 67% after recrystallization. The oily residue
obtained by evaporation of the supernatant contained
Ph3P=S, Ph3P=O, and free PPh3 as the major components,
as determined by 1H and 31P NMR spectroscopy. Addition-
ally, a very small amount of the dithiolato complex
[Cu4{S2C=(tBu-fy)}2(PPh3)4] (5a; see below) was produced.
The formation of 4a also took place when stirring 3a in
MeCN under aerobic conditions in the absence of NEt3,
but the reaction was much slower. It is therefore clear that
an oxidant is required for this reaction to take place and
that the deprotonation does not require an added base. Fi-
nally, the reaction of 3a with the oxidant base 1,4-benzoqui-
Scheme 3. Proposed reaction path for the formation of 4a–c from
none in a 2:1 molar ratio was carried out under a nitrogen
3a–c. tBu-fy groups have been omitted for clarity.
atmosphere in MeCN at room temperature. Under these
conditions, the gradual formation of a yellowish orange
precipitate of 4a was observed within seven hours. The
product was isolated in 73% yield after recrystallization and
In contrast, similar sulfide-bridged dithiolato ligands
the compounds Ph3P=S, 1,4-hydroquinone, and free PPh3 have not been produced from previously described dithioato
1
were identified by H and 31P NMR spectroscopy as the complexes of the type [Cu(S2CR)(PRЈ3)2] containing a hy-
major components present in the supernatant.
drogen atom in the β position, such as those with R =
The analogous complexes [Cu2{[SC=(tBu-fy)]2S}L2] with Me,[38] or CH=C(OH)C6H4Me-p.[39] Both the presence of
–
L = PCy3 (4b) or L2 = dppf (4c) were similarly obtained by the relatively acidic H9 hydrogen atom in (tBu-Hfy)CS2
stirring suspensions of 3b or 3c, respectively, in MeCN in and the electron-donating ability of (tBu-fy)=CS2 appear
2–
the presence of NEt3 and atmospheric oxygen. The yield of to be crucial for the initial deprotonation/oxidation steps
4b (75%) was appreciably higher than of 4c (51%) because leading to 4a–c.
Eur. J. Inorg. Chem. 2006, 115–126
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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117

J. Vicente, P. González-Herrero, Y. García-Sánchez, P. G. Jones, D. Bautista
FULL PAPER
2–
Copper(
Phosphanes
I
) Complexes with the (tBu-fy)=CS2 Ligand and
investigation and a complete study will be reported else-
where.
The neutral CuI complexes [Cu4{S2C=(tBu-fy)}2L4] [L =
PPh3 (5a), P(C6H4OMe-p)3 (5b) and PiPr3 (5d) or L2 = dppf
(5c)] were obtained by treating 1 with [Cu(NCMe)4]PF6, the
corresponding phosphane, and piperidine in a 1:2:2:1 molar
ratio in MeCN (Scheme 2). The products precipitate in this
solvent as bright yellow (5a,b,d) or yellowish orange (5c)
Copper(II) and Copper(III) Complexes with the (tBu-
fy)=CS2 Ligand
2–
The poorly soluble CuII complex (Pr4N)2[Cu{S2C=(tBu-
microcrystalline solids and can be isolated in moderate to fy)}2] [(Pr4N)26] precipitated as a brown solid upon treat-
high yields. Compounds 5a–d display a moderate stability ment of the dithioate 1 with Cu(ClO4)2·6H2O and (Pr4N)-
in solution, which depends on the phosphane; thus, the OH in a 2:1:2 molar ratio in MeCN under an inert atmo-
PiPr3 complex 5d is the least stable and decomposes in sphere, (Scheme 2). Although [(Pr4N)26] is air stable in the
CDCl3 within 2 h, while the CDCl3 solutions of the solid state, it is slowly oxidized by atmospheric oxygen to
P(C6H4OMe-p)3 complex 5b are stable for more than 24 h. the CuIII complex [Cu{S2C=(tBu-fy)}2]– (7) when sus-
The preparation of analogous complexes with PCy3 or pended in MeCN or CH2Cl2. Thus, the green salt Pr4N7
dppm did not succeed under similar conditions, probably was obtained almost quantitatively by bubbling air through
because of their lower stabilities.
an MeCN suspension of (Pr4N)26. Alternatively, Pr4N7 was
The structures of 5a–d could not be determined by X-ray obtained in high yield when the reaction of 1 with Cu-
diffraction studies because the crystals were not of sufficient (ClO4)2·6H2O and (Pr4N)OH was carried out under atmo-
quality or presented severe twinning problems. However, spheric conditions. The salt PPN7 was similarly obtained
their composition and the copper/dithiolate/phosphane ra- from 1, CuCl2·2H2O, PPNCl, and piperidine in a 2:1:1:2
tio were unambiguously determined by means of elemental molar ratio. The only previously reported CuIII complex
analyses and 1H NMR spectroscopy (see Experimental Sec- with a 1,1-ethylenedithiolato ligand is [Cu(ded)2]–, which
tion for details). The H, 13C, and 31P NMR spectroscopic was prepared from the oxidation of [Cu(ded)2]2– with H2O2,
1
data are consistent with highly symmetrical structures con- I2, or Cu2+ ions.[25,26] In comparison, the formation of the
taining equivalent dithiolato ligands and phosphanes. CuIII complex 7 takes place under milder conditions and
Given the preference of CuI for a trigonal planar or tetrahe- represents an uncommon example of aerobic oxidation of
dral coordination geometry and its tendency to form high a CuII complex. We have previously observed that the (flu-
nuclearity thiolato complexes with extensive cuprophilic in- oren-9-ylidene)methanedithiolato ligand and its 2,7-disub-
teractions, a dinuclear formulation for 5a–d is unlikely. Evi- stituted derivatives facilitate the oxidation of AuI to
dence for a tetranuclear formulation was obtained from AuIII [28] and PtII to PtIV,[29] which can be attributed to their
their positive-ion FAB mass spectra. The tetranuclear [M+] stronger electron-donating character as compared with
ions are observed with very low relative abundances for 5b other, more commonly studied 1,1-ethylenedithiolato li-
(m/z = 2368) and 5c (m/z = 2068). Heavier ions are not gands.
observed, except for the [M + Cu]+ ions. All four complexes
undergo very extensive fragmentations in FAB, which result
in the loss of phosphane ligands and CuL+ units and/or the
cleavage of C–S bonds to form sulfide complexes, most of
which are tetranuclear. Significantly abundant fragments
Crystal Structures of the Complexes
that
support
the
tetranuclear
formulation
are
The crystal structures of 3a (Figure 2), 3c·CH2Cl2 (Fig-
[Cu4{S2C=(tBu-fy)}2L3]+ for 5b, [Cu4S{S2C=(tBu-fy)}L]+ ure 3), 4a·4Me2CO (Figure 4), and 4c·CH2Cl2 (Figure 5)
and [Cu4S{S2C=(tBu-fy)}2L]+ for 5a,b, [Cu4{S2C=(tBu- were solved by X-ray diffraction studies. Selected bond
fy)}2L]+ and [Cu4{S2C=(tBu-fy)}2]+ for 5a,d, and lengths and angles are listed in Tables 1, 2, and 3. The mol-
[Cu4S{S2C=(tBu-fy)}(dppf)2]+ for 5c (see Supporting Infor- ecular structures of 3a and 3c show the copper atom in
mation). Tetranuclear structures have been found for the a distorted tetrahedral environment. The main distortion
related complexes [M4(cpdt)2(dppm)4] (M = Cu[23] and originates from the constraints imposed by the four-mem-
Ag[40]),
[Ag4(i-mnt)2(dppm)4],[41]
and
[Cu4(CS3)2- bered chelate ring, which lead to S–Cu–S angles of
(dppm)4],[42] which have their metal atoms in a nearly 74.48(2)° (3a) and 74.38(3)° (3c). The steric hindrance of
planar arrangement and the dithiolato ligands acting as the PPh3 ligands leads to a relatively wide P(1)–Cu–P(2)
bridging tetradentate ligands above and below the M4 core angle of 129.25(3)° in 3a. The chelating dppf ligand in 3c
(Figure 1, b). The structures of 5a–d probably have similar adopts a staggered conformation leading to a bite angle of
Cu4S4 cores but with four phosphane groups instead of 112.76(4)°, which is closer to the ideal value for a tetrahe-
eight (Scheme 2), which would be consistent with their dral geometry. Similar coordination environments around
NMR spectroscopic data.
the Cu atom and Cu–S bond lengths have been found in
Complexes 5a–d are luminescent at room temperature the analogous dithioato complexes [Cu(S2CR)(PPh3)2] [R =
[44]
in the solid state and also in solution at 77 K. Their Me,[38] Ph,[43] p-To,[30] C5Me5
excitation and emission properties are currently under CH=C(OH)C6H4Me-p].[39]
CO2Me[45] and
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Copper Complexes with (2,7-Di-tert-butylfluoren-9-ylidene)methanedithiolate
FULL PAPER
Figure 4. Thermal ellipsoid plot (30% probability) of complex 4a.
H atoms and tBu groups have been omitted for clarity.
Figure 2. Thermal ellipsoid plot (50% probability) of complex 3a.
H atoms have been omitted for clarity.
Figure 5. Thermal ellipsoid plot (50% probability) of complex 4c.
H atoms and tBu groups have been omitted for clarity.
Figure 3. Thermal ellipsoid plot (50% probability) of complex 3c.
H atoms have been omitted for clarity.
Table 1. Selected bond lengths [Å] and angles [°] for 3a and
3c·CH2Cl2.
Complexes 4a and 4c exhibit essentially the same struc-
tural arrangement for the Cu2{[SC=(tBu-fy)]2S} unit as the
condensed dithiolato ligand coordinates to the two copper
atoms in different ways. The atom Cu(1) is bonded to the
two terminal sulfur atoms S(1) and S(2) and one PPh3 li-
gand (or one of the PPh2 units of dppf), resulting in a
slightly distorted trigonal planar geometry, whereas the
atom Cu(2) is attached to the other PPh3 ligand or the sec-
ond PPh2 unit, and to the dithiolato ligand through the
C(29)=C(30) double bond and the terminal S(1) atom,
which thus bridges the two copper atoms. The coordination
3a
3c·CH2Cl2
2.4196(9)
2.3806(10)
2.2433(9)
2.2325(10)
1.680(4)
1.694(3)
1.520(5)
74.38(3)
112.76(4)
118.7(2)
Cu(1)–S(1)
Cu(1)–S(2)
Cu(1)–P(1)
Cu(1)–P(2)
S(1)–C(1)
S(2)–C(1)
C(1)–C(2)
S(1)–Cu(1)–S(2)
P(1)–Cu(1)–P(2)
S(1)–C(1)–S(2)
2.3901(8)
2.4357(8)
2.2449(7)
2.2413(8)
1.674(3)
1.693(3)
1.520(4)
74.48(2)
129.25(3)
120.30(16)
around Cu(2) is also trigonal planar if we consider the Cu(1)–S(1) distance [2.3413(10) (4a) or 2.3298(11) Å (4c)].
atoms S(1), P(1), and the C(29)=C(30) bond centroid. The There is also an appreciably longer Cu(2)–S(2) distance of
Cu(1)–S(2) and Cu(2)–S(1) bond lengths are very similar 2.7336(9) (4a) or 2.7878(11) Å (4c), which is indicative of
[range 2.2156(10)–2.2659(9) Å] and slightly shorter than the a much weaker interaction. The distance of Cu(1) to the
Eur. J. Inorg. Chem. 2006, 115–126
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119

J. Vicente, P. González-Herrero, Y. García-Sánchez, P. G. Jones, D. Bautista
FULL PAPER
Table 2. Selected bond lengths [Å] and angles [°] for 4a·4Me2CO.
the PPh2 groups occupy the same positions as the two inde-
pendent PPh3 ligands in 4a (P···P = 5.438 Å).
Cu(1)–P(2)
Cu(1)–S(2)
Cu(1)–S(1)
2.2053(9)
Cu(2)–S(2)
2.7336(9)
1.773(3)
1.763(3)
1.769(3)
1.773(3)
1.360(4)
1.401(4)
2.2576(9) S(1)–C(10)
2.3413(10) S(2)–C(30)
2.6999(5) S(3)–C(10)
2.087(3)
2.2069(8) C(9)–C(10)
2.255(3)
2.2659(9)
128.30(4)
128.92(3)
102.76(3)
124.26(3)
124.23(3)
91.42(3)
Cu(1)–Cu(2)
Cu(2)–C(30)
Cu(2)–P(1)
Cu(2)–C(29)
Cu(2)–S(1)
P(2)–Cu(1)–S(2)
P(2)–Cu(1)–S(1)
S(2)–Cu(1)–S(1)
P(1)–Cu(2)–S(1)
P(1)–Cu(2)–S(2)
S(1)–Cu(2)–S(2)
NMR Spectra
S(3)–C(30)
1
The H and 13C{1H} NMR spectra of complexes 2 and
C(29)–C(30)
3a–e show one set of signals for the protons and carbon
atoms of the dithioato ligand, which are slightly modified
with respect to those of the free dithioate 1,[54] with the 9-
H resonance in the range δ = 5.35–5.68 ppm and the CS2
resonance in the range δ = 251.5–259.3 ppm. On the basis
of these data, complex 2 most probably has a highly sym-
metrical oligomeric structure (see above).
C(10)–S(1)–Cu(1)
Cu(2)–S(1)–Cu(1)
C(30)–S(2)–Cu(1)
Cu(1)–S(2)–Cu(2)
C(10)–S(3)–C(30) 103.78(14)
S(3)–C(10)–S(1)
89.29(11)
71.73(3)
98.61(10)
64.68(2)
115.50(16)
116.71(16)
C(10)–S(1)–Cu(2) 105.47(10) S(2)–C(30)–S(3)
The crystal structures of 4a and 4c show that the con-
densed ligand contains two tBu-fy groups in different envi-
ronments. Because the rotation around the C9=CS2 double
bonds is expected to be hindered at room temperature, the
two halves of each of these groups are not equivalent.
Therefore, if their solid-state structures were retained in
solution, the 1H and 13C{1H} NMR spectra of 4a–c should
display the resonances corresponding to four different tBu
groups, four sets of signals for the aromatic H and C atoms,
and two signals for both the C9 and CS2 atoms. Addition-
ally, two different resonances should be expected in the 31P
NMR spectra. However, the 1H, 13C{1H}, and 31P{1H}
NMR spectra of 4a–c reveal that the tBu-fy groups are
equivalent in solution, as are the two PPh3 or PCy3 ligands
in 4a,b or the PPh2 groups of the dppf ligand in 4c. Thus,
Table 3. Selected bond lengths [Å] and angles [°] for 4c·CH2Cl2.
Cu(1)–P(2)
Cu(1)–S(2)
Cu(1)–S(1)
Cu(1)–Cu(2)
Cu(2)–C(30)
Cu(2)–P(1)
2.1821(10) Cu(2)–S(2)
2.2156(10) S(1)–C(10)
2.3298(11) S(2)–C(30)
2.7878(11)
1.757(3)
1.774(4)
1.772(3)
1.790(3)
1.369(5)
1.396(5)
2.7568(6)
2.114(3)
S(3)–C(10)
S(3)–C(30)
2.2172(10) C(9)–C(10)
Cu(2)–S(1)
2.2529(9)
2.256(3)
C(29)–C(30)
Cu(2)–C(29)
P(2)–Cu(1)–S(2)
P(2)–Cu(1)–S(1)
S(2)–Cu(1)–S(1)
P(1)–Cu(2)–S(1)
P(1)–Cu(2)–S(2)
S(1)–Cu(2)–S(2)
137.20(4)
118.41(4)
103.77(4)
118.84(4)
127.88(4)
89.76(3)
C(10)–S(1)–Cu(1) 92.13(12)
Cu(2)–S(1)–Cu(1) 73.94(3)
C(30)–S(2)–Cu(1) 98.77(11)
Cu(1)–S(2)–Cu(2) 65.71(3)
C(10)–S(3)–C(30) 104.51(15)
S(1)–C(10)–S(3)
117.10(18)
115.10(19)
1
C(10)–S(1)–Cu(2) 106.48(11) S(2)–C(30)–S(3)
the H NMR spectra show only two singlets for the tBu
groups and two sets of resonances for the aromatic protons;
the two signals corresponding to the 1-H and 8-H atoms
C(29)=C(30) bond centroid of 2.056 (4a) or 2.072 Å (4c) is are considerably downfield-shifted, as is the case for coordi-
close to the upper limit of the range found for the majority nated (fluoren-9-ylidene)methanedithiolato ligands,[28] and
of alkene complexes of copper() in the Cambridge Struc- also the most affected by the lack of symmetry of the tBu-fy
tural Database (1.840–2.110 Å).[46] The bond length of the groups, appearing at very different chemical shifts (ranges δ
uncoordinated C(9)=C(10) double bond [1.360(4) (4a) or = 9.61–9.71 and 8.55–8.69 ppm, respectively). The 13C{1H}
1.369(5) Å (4c)] is similar to the corresponding distances NMR spectra show two sets of resonances for the carbon
found for 1,1-ethylenedithiolato ligands,[28] which are usu- atoms of the ligand except for the C-9 and CS2 atoms, each
ally close to the higher limit of the range found for of which gives rise to only one resonance; the CS2 reso-
C(sp2)=C(sp2) double bonds (1.294–1.392 Å),[47] whereas nance appears as a slightly broad signal for 4a,b, but in the
the C(29)–C(30) distance of 1.401(4) (4a) or 1.396(5) Å (4c) case of 4c resolves as a triplet because of coupling with two
is slightly longer, as expected for a coordinated C=C bond. equivalent phosphorus atoms. The 31P NMR spectra show
The Cu(1)–Cu(2) distance of 2.6999(5) (4a) or 2.7568(6) Å a relatively broad singlet. The dppf ligand in 4c gives rise to
1
(4c) is slightly shorter than the sum of the van der Waals six multiplets in the room temperature H NMR spectrum
radii for Cu (2.80 Å[48]) and typical of the cuprophilic inter- corresponding to the two inequivalent Ph rings of each
actions found in numerous di- or polynuclear copper() PPh2 group, and four broad resonances corresponding to
complexes with bridging thiolato ligands.[49–53] The planes the protons of the two equivalent Cp rings. This means that
S(1)–C(10)–S(3) and S(3)–C(30)–S(2) form an angle of 75° the diphosphane is essentially rigid in solution and does not
(4a) or 77° (4c). The fluoren-9-ylidene fragments are nearly undergo the fluxional process observed in 5c (see below)
planar, with their respective mean planes being perpendicu- and other metal complexes with bridging dppf,[55–60] which
lar to each other [89° (4a) or 90° (4c)] and slightly rotated involves a conformation change leading to the equivalence
with respect to the corresponding S–C–S planes. The dppf of the phenyl groups and the two Hα and Hβ atoms of the
ligand in 4c adopts an eclipsed conformation, with the Cp rings on the NMR timescale. The absence of any dy-
P(1)–C(81) and P(2)–C(86) bonds rotated by 79° with re- namic process affecting the dppf ligand was further con-
spect to each other. This results in a large distance between firmed by a variable-temperature NMR study of 4c, which
1
both phosphorus atoms (5.275 Å) and allows the flexible revealed no changes in the H and 31P resonances arising
dppf ligand to bridge the copper atoms in such a way that from this diphosphane between –65 and +50 °C in CDCl3.
120
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Eur. J. Inorg. Chem. 2006, 115–126

Copper Complexes with (2,7-Di-tert-butylfluoren-9-ylidene)methanedithiolate
FULL PAPER
Scheme 4. tBu-fy groups have been omitted for clarity.
In view of these observations, the two possible explanations centroid axis, together with the concerted twist around the
for the NMR spectroscopic data of 4a–c are: (i) the exis- P–Cipso(Cp) and P–Cu bonds, causes the two Hα and Hβ
tence of
a
dynamic process mainly affecting the atoms and the Ph rings on each PPh2 group to exchange
Cu2{[SC=(tBu-fy)]2S} unit that causes the copper atoms to their positions. The resonances of the protons of the dithiol-
interchange their coordination environments, or (ii) a dif- ato ligands in 5c remain practically unchanged between
ferent, symmetrical structure of the complexes in solution. –40 and 25 °C.
1
The possible dynamic process is represented in Scheme 4
The H NMR spectrum of the CuII complex (Pr4N)26 in
for 4c. The transition from the solid state form C (or its CDCl3 shows broad signals for the Pr4N+ cation, while the
equivalent CЈ) to the intermediate, C2-symmetrical form D resonances corresponding to the ligand protons are not ob-
requires only minor rearrangements of the molecules in- served, which can be attributed to its paramagnetic nature.
volving the rupture of the relatively weak coordination of The 1H and 13C NMR spectroscopic data of the Q7 salts (Q
C(29)=C(30) to Cu(2) and the strengthening of the Cu(2)– = Pr4N+, PPN+) are fully consistent with a square-planar
S(2) interaction to form a symmetrical bridge, while retain- structure. The chemical shifts of the H and C resonances of
1
ing the conformation of the dppf ligand. However, the H the dithiolato ligand are very similar to those observed for
and 31P NMR spectra of 4a–c show that the signals arising the analogous AuIII complex.[28]
from the condensed ligand and the phosphorus atoms do
not split, even at –90 °C in CD2Cl2, which could be due to
a very low activation energy and/or to negligible differences
in the chemical shifts of the H nuclei of the inequivalent
IR Spectra
tBu-fy groups (or the P nuclei of the phosphanes) in form
C. The possibility that the actual structure in solution is
form D would also be consistent with the experimental ob-
The solid-state infrared spectrum of the dithioato com-
servations; in this case, the arrangement found in the solid- plex 2 displays one band at 975 cm–1 assignable to one of
state structures would most probably be a consequence of the two ν(CS2) modes,[43] while for the phosphane com-
packing forces in the crystals.
plexes 3a–e the corresponding absorption appears around
1
The H and 13C{1H} NMR spectra of complexes 5a–d 1010 cm–1. The dinuclear complexes 4a–c give rise to one
display very similar sets of resonances for the protons and band associated with the C=CS2 double bonds at around
2–
carbon atoms of the (tBu-fy)=CS2 ligand, which indicate 1500 cm–1. The expected ν(C=CS2) band[61] arising from the
2–
that all of them have similar structures with equivalent and (tBu-fy)=CS2 ligand in complexes 5a–d occurs in the
symmetrical dithiolates. The resonances of the 1-H and 8- range 1482–1490 cm–1, while for the CuII complex (Pr4N)26
H atoms are typically downfield-shifted (range δ = 9.37– it is observed at 1480 cm–1 and for the CuIII salts Q7 at
9.54 ppm). The resonances of the Ph and Cp protons of the 1548 (Pr4N+) or 1552 cm–1 (PPN+). We have previously
dppf ligand in 5c are observed as broad signals at room shown that the variations in the energies of the ν(C=CS2)
temperature, suggesting fluxional behavior. At –40 °C, the bands can be attributed to the oxidation state of the metal
Cp resonances resolve into four signals, while the Ph rings center and the nature of the ligands attached to it, which
give rise to five broad signals, indicating that the two Cp affect the strength of the π component of the C=CS2
rings and PPh2 groups of each dppf are equivalent, while bond.[28] Usually, a higher oxidation state and/or the pres-
the two Ph rings of each PPh2 group are not. The fluxional ence of weaker donor ligands increase the energy of the
behavior of a bridging dppf ligand has been observed pre- ν(C=CS2) band, which is consistent with the high energy
viously and thoroughly described for other di- or polynu- observed for the CuIII complex. The spectra of the salts Q7
clear complexes.[55–60] The opposite twisting of the two also show one intense band at 416 (Pr4N+) or 420 cm–1
halves of the ferrocene fragment around the Cp centroid– (PPN+) assignable to the ν(Cu–S) mode.
Eur. J. Inorg. Chem. 2006, 115–126
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121

J. Vicente, P. González-Herrero, Y. García-Sánchez, P. G. Jones, D. Bautista
FULL PAPER
Electronic Absorption Spectra
unit. The lowest-energy band can be assigned to a metal-to-
ligand charge-transfer (MLCT) transition by analogy with
The UV/Visible absorption spectra of compounds 2–7
were measured in the range 200–700 nm in CH2Cl2 at
298 K. All of them display the bands arising from the aro-
matic part of the dithioato or dithiolato ligands at around
230, 260–270 and 300 nm.[28] The bands above 300 nm are
listed in Table 4. The low intensity band centered at about
360 nm for dithioato complexes 3a–d is probably the result
of the modification of the band observed for the free dithio-
ate 1b at 346 nm, which arises from n–π* transitions within
other isoelectronic bis(dithiolato) complexes.[24] The AuIII
and PtII complexes with the same dithiolato ligand show
this band at 410[28] or 490 nm,[29] respectively. The absorp-
tion spectrum of the CuII complex (Pr4N)26 is similar to
those of the Q7 salts, except for the lowest-energy band,
which is observed at 430 nm.
Conclusions
–
the CS2 group. In the case of 3e (L2 = dppm) this band
The series of complexes [Cu{S2C(tBu-Hfy)}L2] [L =
PPh3 (3a), PCy3 (3b), PiPr3 (3d); L2 = dppf (3c), dppm (3e)]
were prepared by the reaction of the oligomeric compound
[Cun{S2C(tBu-Hfy)}n] (2) with different P ligands. Com-
pounds 3a–c react with atmospheric oxygen in the presence
of NEt3 to give the dinuclear complexes [Cu2{[SC=(tBu-fy)]2-
S}L2] [L = PPh3 (4a), PCy3 (4b); L2 = dppf (4c)], containing
a novel, sulfide-bridged dithiolato ligand, formally resulting
from the condensation of two dithioato ligands with loss of
a sulfide ion and two protons. The proposed reaction path
for the formation of 4a–c involves the initial deprotonation
and oxidation of 3a–c, the formation of a disulfide-bridged
dinuclear species and the subsequent sulfur abstraction by
one of the phosphane ligands. The first family of Cu
complexes with the (2,7-di-tert-butylfluoren-9-ylidene)-
methanedithiolato ligand has been prepared, including a
series of CuI complexes of the type [Cu4{S2C=(tBu-fy)}2L4]
[L = PPh3 (5a), P(C6H4OMe-p)3 (5b), PiPr3 (5d) or L2 =
dppf (5c)] and salts of the CuII complex [Cu{S2C=(tBu-
fy)}2]2– (6) and the CuIII complex [Cu{S2C=(tBu-fy)}2]– (7).
appears at 391 nm. The spectrum of compound 2 shows
two very broad bands at 393 and 438 nm, which are proba-
bly also related to these transitions.
Table 4. Electronic absorption data for compounds 2–7 in CH2Cl2
solution (ca. 5×10–5 ) at 298 K (λ Ͼ 300 nm).
Compound
λ [nm] (ε [–1 cm–1])
2
3a
393, 438[a]
353 (5200)
360 (6000)
356 (6800)
357 (6100)
3b
3c
3d
3e
391 (4100)
4a
369 (20900), 409 (24600), 467 (sh, 9000)
372 (sh, 20700), 407 (22700), 500 (sh, 7800)
367 (19800), 403 (29100), 452 (sh, 9300)
415 (sh, 36300), 435 (42200)
418 (sh, 36900), 440 (48000)
411 (sh, 31700), 442 (37400)
423 (sh, 63800), 442 (76800)
399 (36800), 430 (62500)
376 (16200), 397 (43600), 451 (64100)
377 (29900), 397 (51300), 451 (67100)
4b
4c
5a
5b
5c
5d
(Pr4N)26
Pr4N7
PPN7
[a] Accurate concentration and ε values could not be measured for
this compound because of its very low solubility.
Experimental Section
General Considerations, Materials, and Instrumentation: All reac-
tions were carried out at room temperature under an atmosphere
of nitrogen using Schlenk techniques, except in the cases indicated.
The absorptions of complex 4a above 300 nm occur as
broad, medium-intensity bands at 369 and 409 nm, with a
shoulder at 467 nm. The analogous complexes 4b and 4c
show a very similar pattern. The probable origins of these
bands are intraligand transitions associated with the C=CS2
units and ligand-to-metal charge-transfer transitions
(LMCT), which are usually observed in this region for CuI
complexes with sulfur donor ligands.[62]
Solvents were dried by standard methods and distilled under nitro-
[63]
gen before use. The compounds [Cu(NCMe)4]PF6
and
(pipH)[(tBu-Hfy)CS2][54] (1) were prepared following published
procedures. All other reagents were obtained from commercial
sources and used without further purification. NMR spectra were
recorded on Bruker Avance 200, 300, or 400 spectrometers at
The spectra of the dithiolato complexes 5a–d display a 298 K, unless otherwise indicated. Chemical shifts are referenced
to internal TMS (1H and 13C{H}) or external 85% H3PO4
very intense absorption band at around 440 nm, with a
(31P{H}). The assignments of the 1H and 13C{H} NMR spectra
shoulder on the higher energy slope between 411 and
were made with the help of HMBC and HSQC experiments.
420 nm. Very similar absorptions have been observed for
Scheme 1 shows the atom numbering of the dithiolato ligand. Melt-
ing points were determined on a Reichert apparatus and are uncor-
rected. Elemental analyses were carried out with a Carlo Erba 1106
neutral AuI–phosphane complexes containing the (fluoren-
9-yliden)methanedithiolato ligand or its substituted deriva-
tives (415 nm), which are assignable to LMCT transi-
microanalyzer. Infrared spectra were recorded in the range 4000–
tions.[28]
200 cm–1 on a Perkin–Elmer 16F PC FT-IR spectrophotometer as
Nujol mulls between polyethylene sheets or KBr pellets. UV/Visible
absorption spectra were recorded on an Unicam UV500 spectro-
The absorption spectra of the CuIII salts Q7 are almost
identical and show two medium intensity bands at 377 and
397 nm and a very intense band at 450 nm. The two higher photometer. FAB mass spectra were recorded on a VG Autospec
500 mass spectrometer using 3-nitrobenzyl alcohol as matrix.
energy bands appear with very little differences from those
in the spectra of other square-planar AuIII and PtII com-
[Cun{S2C(tBu-Hfy)}n] (2): Dithioate 1 (473 mg, 0.99 mmol) was
added to a solution of [Cu(NCMe)4]PF6 (359 mg, 0.96 mmol) in
2–
plexes containing the (tBu-fy)=CS2 ligand and can be as-
signed to intraligand transitions associated with the C=CS2 MeCN (20 mL). An immediate reaction was observed, with forma-
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Copper Complexes with (2,7-Di-tert-butylfluoren-9-ylidene)methanedithiolate
FULL PAPER
tion of a dark brown precipitate. The mixture was stirred for 30 min
and the solid collected by filtration, washed with MeCN (2×2 mL),
and vacuum-dried to give 2. Yield: 389 mg (97%), m.p. 184 °C
3, C-4, Cp), 34.8 (CMe3), 31.5 (CMe3) ppm. 31P{1H} NMR
(75.5 MHz, CDCl3): δ = –13.33 ppm. C56H53CuFeP2S2 (971.51):
calcd. C 69.23, H 5.50, S 6.60; found C 69.03, H 5.57, S 6.32.
(dec.). IR (Nujol): ν = 975 cm–1 (CS2). 1H NMR (400.9 MHz,
˜
[Cu{S2C(tBu-Hfy)}(PiPr3)2] (3d): PiPr3 (167 µL, 0.88 mmol) was
added to a suspension of 2 (182 mg, 0.44 mmol) in MeOH (8 mL)
and the mixture was stirred for 2 h. A salmon-pink precipitate
formed, which was filtered off, washed with methanol (2×2 mL),
and vacuum-dried to give 3d. Yield: 269 mg (84%), m.p. 110 °C
3
CDCl3): δ = 7.61 (d, JH,H = 8.0 Hz, 2 H, 4-H, 5-H), 7.47 (br., 2
3
4
H, 1-H, 8-H), 7.42 (dd, JH,H = 8.0, JH,H = 1.5 Hz, 2 H, 3-H, 6-
H), 5.68 (s, 1 H, 9-H), 1.29 (s, 18 H, tBu) ppm. 13C{1H} NMR
(50.3 MHz, CDCl3): δ = 259.3 (CS2), 150.5 (C-2, C-7), 144.6 (C-
8a, C-9a), 138.5 (C-4a, C-4b), 125.4 (C-3, C-6), 121.6 (C-1, C-8),
119.2 (C-4, C-5), 71.3 (C-9), 35.0 (CMe3), 31.5 (CMe3) ppm.
C22H25CuS2 (417.12): calcd. C 63.35, H 6.04, S 15.37; found C
62.95, H 6.06, S 15.21.
(dec.). IR (Nujol): ν = 1012 cm–1 (CS2). 1H NMR (400.9 MHz,
˜
3
CDCl3): δ = 7.72 (s, 2 H, 1-H, 8-H), 7.58 (d, JH,H = 7.9 Hz, 2 H,
4-H, 5-H), 7.36 (d, 3JH,H = 7.9 Hz, 2 H, 3-H, 6-H), 5.46 (s, 1 H, 9-
H), 2.13 (m, 6 H, CHMe2), 1.35 (s, 18 H, tBu), 1.22 (m, 36 H,
[Cu{S2C(tBu-Hfy)}(PPh3)2] (3a): PPh3 (90 mg, 0.34 mmol) was CHMe2) ppm. 13C{1H} NMR (75.5 MHz, CDCl3): δ = 252.8
added to a suspension of 2 (64 mg, 0.15 mmol) in CH2Cl2 (15 mL)
and the mixture was stirred for 1 h. Partial evaporation of the re-
sulting orange solution and addition of methanol (15 mL) led to
the precipitation of a pale-pink solid, which was filtered off, washed
with methanol (2×2 mL), and vacuum-dried to give 3a. Yield:
(CS2), 149.1 (C-2, C-7), 145.9 (C-8a, C-9a), 138.4 (C-4a, C-4b),
124.4 (C-3, C-6), 122.1 (C-1, C-8), 118.7 (C-4, C-5), 72.4 (C-9), 34.9
(CMe3), 31.6 (CMe3), 23.6 (CHMe2), 20.1 (CHMe2) ppm. 31P{1H}
NMR (162.3 MHz, CDCl3):
δ = 21.93 ppm. C40H67CuP2S2
(737.60): calcd. C 65.14, H 9.16, S 8.69; found: C 65.01, H 9.23, S
104 mg (72%), m.p. 120 °C (dec.). IR (Nujol): ν = 1011 cm–1 (CS2). 8.56.
˜
1H NMR (400.9 MHz, CDCl3): δ = 7.84 (s, 2 H, 1-H, 8-H), 7.63
[Cu{S2C(tBu-Hfy)}(dppm)] (3e): This orange compound was pre-
pared as described for 3c, from 2 (262 mg, 0.63 mmol) and bis(di-
phenylphosphanyl)methane (251 mg, 0.65 mmol). Yield: 415 mg
3
3
(d, JH,H = 8.0 Hz, 2 H, 4-H, 5-H), 7.40 (d, JH,H = 7.8 Hz, 2 H,
3-H, 6-H), 7.28–7.22 (m, 18 H, o-H + p-H, Ph), 7.10 (m, 12 H, m-
H, Ph), 5.38 (s, 1 H, 9-H), 1.26 (s, 18 H, tBu) ppm. 13C{1H} NMR
(50.3 MHz, CDCl3): δ = 256.4 (CS2), 149.3 (C-2, C-7), 144.7 (C-
8a, C-9a), 138.5 (C-4a, C-4b), 133.6 (C-1 + C-2, C-6, Ph), 129.3
(C-4, Ph), 128.3 (C-3, C-5, Ph), 124.4 (C-3, C-6), 123.2 (C-1, C-8),
118.8 (C-4, C-5), 71.3 (C-9), 34.9 (CMe3), 31.6 (CMe3) ppm.
(82%), m.p. 151 °C (dec.). IR (Nujol): ν = 1010 cm–1 (CS2). 1H
˜
NMR (400.9 MHz, CDCl3): δ = 7.70 (br., 2 H, 1-H, 8-H), 7.59 (d,
3
3JH,H = 8.0 Hz, 2 H, 4-H, 5-H), 7.35 (d, JH,H = 8.0 Hz, 2 H, 3-H,
6-H), 7.20 (br. m, 8 H, o-H, Ph), 7.13 (br. m, 4 H, p-H, Ph), 6.96
(br. m, 8 H, m-H, Ph), 5.61 (s, 1 H, 9-H), 3.00 (s, 2 H, CH2), 1.23
(s, 18 H, tBu) ppm. 13C{1H} NMR (75.5 MHz, CDCl3): δ = 256.1
(CS2), 149.3 (C-2, C-7), 145.8 (C-8a, C-9a), 141.8 (C-4a, C-4b),
138.4 (C-1, Ph), 135.0 (C-2, C-6 Ph), 129.1 (C-4, Ph), 128.1 (C-3,
C-5, Ph), 124.2 (C-3, C-6), 122.4 (C-1, C-8), 118.7 (C-4, C-5), 71.4
(C-9), 34.8 (CMe3), 31.6 (CMe3) (CH2 of dppm not observed) ppm.
31P{1H} NMR (162.3 MHz, CDCl3):
δ = 0.66 ppm (br).
C58H55CuP2S2 (941.70): calcd. C 73.98, H 5.88, S 6.81; found C
73.79, H 5.94, S 6.47.
[Cu{S2C(tBu-Hfy)}(PCy3)2] (3b): This salmon-pink compound was
prepared as described for 3a, from 2 (198 mg, 0.47 mmol) and PCy3
(270 mg, 0.96 mmol). Yield: 391 mg (84%), m.p. 120 °C (dec.). IR
31P{1H} NMR (162.3 MHz, CDCl3):
δ
=
–12.42 ppm.
1
(Nujol): ν = 1014 cm–1 (CS2). H NMR (400.9 MHz, CDCl3): δ =
C47H47CuP2S2 (801.52): calcd. C 70.43, H 5.91, S 8.00; found C
70.18, H 6.21, S 7.76.
˜
3
7.89 (br., 2 H, 1-H, 8-H), 7.57 (d, JH,H = 8.0 Hz, 2 H, 4-H, 5-H),
7.35 (d, JH,H = 8.0 Hz, 2 H, 3-H, 6-H), 5.35 (s, 1 H, 9-H), 1.87–
3
[Cu2{[SC=(tBu-fy)]2S}(PPh3)2] (4a). Method A: NEt3 (22 µL,
0.17 mmol) was added to a suspension of 3a (160 mg, 0.17 mmol)
in MeCN (10 mL) and the mixture was stirred under atmospheric
conditions for 4 h. The poorly soluble starting material slowly re-
acted to give a green solution, from which a yellowish orange solid
gradually precipitated. The suspension was cooled to –15 °C and
the solid collected by filtration and washed with cold MeCN
(3×4 mL). Recrystallization from CH2Cl2/MeCN gave orange
crystals of 4a, which turned red upon drying under vacuum. Yield:
1.55 (m, 30 H, Cy), 1.37 (br. s, 30 H, tBu + Cy), 1.18 (br. s, 24 H,
Cy) ppm. 13C{1H} NMR (300.1 MHz, CDCl3): δ = 251.5 (CS2),
148.8 (C-2, C-7), 145.2 (C-8a, C-9a), 138.5 (C-4a, C-4b), 124.1 (C-
3, C-6), 123.1 (C-1, C-8), 118.5 (C-4, C-5), 71.7 (C-9), 34.9 (CMe3),
33.5 (C-1, Cy), 31.6 (CMe3), 30.1 (C-2, C-6, Cy), 27.8 (C-3, C-5,
Cy), 26.4 (C-4, Cy) ppm. 31P{1H} NMR (162.3 MHz, CDCl3): δ =
12.64 ppm. C58H91CuP2S2 (977.99): calcd. C 71.23, H 9.38, S 6.56;
found C 71.12, H 9.20, S 6.26.
[Cu{S2C(tBu-Hfy)}(dppf)] (3c): dppf (351 mg, 0.63 mmol) was 76 mg (67%).
added to a suspension of 2 (262 mg, 0.63 mmol) in CH2Cl2 (15 mL)
and the mixture was stirred for 1 h. Partial evaporation of the re-
sulting orange solution (5 mL) and addition of pentane (30 mL)
led to the precipitation of an orange solid, which was filtered off,
washed with pentane (2×5 mL), and vacuum-dried to give 3c.
Method B: A solid mixture of 3a (203 mg, 0.22 mmol) and 1,4-
benzoquinone (12 mg, 0.11 mmol) was suspended in MeCN
(10 mL) and stirred for 7 h under an atmosphere of nitrogen. The
reaction took place gradually to give a yellowish orange precipitate,
which was isolated and purified as described for method A to give
Yield: 541 mg (89%), m.p. 198 °C (dec.). IR (Nujol): ν = 1010 cm–1 red crystals of 4a. Yield: 104 mg (73%), m.p. 145 °C (dec.). IR (Nu-
˜
(CS2). 1H NMR (400.9 MHz, CDCl3): δ = 7.87 (br. s, 2 H, 1-H, 8-
jol): ν = 1506 cm–1 (C=CS2). H NMR (400.9 MHz, CDCl3): δ =
1
˜
3
4
H), 7.63 (d, JH,H = 8.0 Hz, 2 H, 4-H, 5-H), 7.56 (m, 8 H, o-H, 9.64, 8.66 (both d, JH,H = 1.4 Hz, 2 H each, 1-H, 8-H), 7.48, 7.40
3
4
3
Ph), 7.39 (dd, JH,H = 8.0, JH,H = 1.3 Hz, 2 H, 3-H, 6-H), 7.32
(both d, JH,H = 8.0 Hz, 2 H each, 4-H, 5-H), 7.24–7.16 (m, 10 H,
(m, 4 H, p-H, Ph), 7.23 (m, 8 H, m-H, Ph), 5.48 (s, 1 H, 9-H), 4.27 3-H, 6-H + C-4, Ph), 7.06 (m, 12 H, C-2, C-6, Ph), 6.94 (m, 12 H,
(br., 4 H, 3-H, 4-H, Cp), 4.14 (br., 4 H, 2-H, 5-H, Cp), 1.21 (s, 18 C-3, C-5, Ph), 1.25, 1.14 (both s, 18 H each, tBu) ppm. 13C{1H}
H, tBu) ppm. 13C{1H} NMR (75.4 MHz, CDCl3): δ = 256.5 (CS2),
NMR (75.45 MHz, CDCl3): δ = 148.9, 148.8 (C-2, C-7), 140.1,
149.5 (C-2, C-7), 145.1 (C-8a, C-9a), 138.5 (C-4a, C-4b), 134.8 (vt, 139.1 (C-8a, C-9a), 138.8 (br., CS2), 136.4, 136.2 (C-4a, C-4b),
N = 31.0 Hz, C-1, Ph), 133.9 (vt, N = 16.8 Hz, C-2, C-6 Ph), 129.6 133.5 (d, 2JC,P = 15.0 Hz, C-2, C-6, Ph), 132.0 (C-9), 130.9 (d, 1JC,P
3
(C-4, Ph), 128.3 (vt, N = 9.6 Hz, C-3, C-5, Ph), 124.4 (C-3, C-6), = 38.4 Hz, C-1, Ph), 129.8 (C-4, Ph), 128.4 (d, JC,P = 10.0 Hz, C-
122.8 (C-1, C-8), 118.7 (C-4, C-5), 77.8 (vt, N = 37.7 Hz, C-1, Cp),
3, C-5, Ph), 123.8, 123.7, 123.0, 122.9 (C-1, C-8, C-3, C-6), 118.1,
73.9 (vt, N = 10.8 Hz, C-2, C-5, Cp), 71.6 (br., C-9), 71.5 (br., C- 117.9 (C-4, C-5), 34.9, 34.8 (CMe3), 31.6, 31.4 (CMe3) ppm.
Eur. J. Inorg. Chem. 2006, 115–126
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
123

J. Vicente, P. González-Herrero, Y. García-Sánchez, P. G. Jones, D. Bautista
FULL PAPER
31P{1H} NMR (162.3 MHz, CDCl3): δ = 7.38 ppm. C80H78Cu2P2S3 Yield: 228 mg (71%), m.p. 123 °C (dec.). IR (KBr): ν = 1482 cm–1
˜
4
(1324.7): calcd. C 72.53, H 5.94, S 7.26; found C 72.56, H 5.88, S
7.03.
(C=CS2). 1H NMR (400.9 MHz, CDCl3): δ = 9.37 (d, JH,H
=
3
1.4 Hz, 4 H, 1-H, 8-H), 7.60 (d, JH,H = 7.9 Hz, 4 H, 4-H, 5-H),
7.25–7.18 (m, 28 H, 3-H, 6-H + o-H, Ph), 6.97 (t, JH,H = 7.3 Hz,
3
[Cu2{[SC=(tBu-fy)]2S}(PCy3)2] (4b): NEt3 (30 µL, 0.24 mmol) was
added to a suspension of 3b (215 mg, 0.22 mmol) in MeCN (8 mL)
and the mixture was stirred under atmospheric conditions for 4 h.
A red precipitate gradually formed, which was filtered off and
washed with MeCN (3×4 mL). The crude product was recrys-
tallized from CH2Cl2/MeCN and vacuum-dried to give 4b as a red
microcrystalline solid. Yield: 113 mg (75%), m.p. 134 °C (dec.). IR
3
12 H, p-H, Ph), 6.72 (t, JH,H = 7.0 Hz, 24 H, m-H, Ph), 1.03 (s,
36 H, tBu) ppm. 13C{1H} NMR (75.4 MHz, CDCl3): δ = 157.9
(br., CS2), 147.7 (C-2, C-7), 140.9 (C-8a, C-9a), 135.7 (C-4a, C-4b),
133.8 (d, 2JC,P = 14.6 Hz, C-2, C-6, Ph), 133.3 (C-9), 132.6 (d, 1JC,P
3
= 30.7 Hz, C-1, PPh3), 129.3 (C-4 PPh3), 128.2 (d, JC,P = 9.1 Hz,
C-3, C-5, PPh3), 124.8 (C-1, C-8), 121.3 (C-3, C-6), 116.9 (C-4, C-
5), 34.8 (CMe3), 31.8 (CMe3) ppm. 31P{1H} NMR (162.3 MHz,
CDCl3): δ = –4.04 ppm. C116H108Cu4P4S4 (2008.5): calcd. C 69.37,
H 5.42, S 6.39; found C 69.16, H 5.56, S 6.25.
(KBr): ν = 1498, 1486 cm–1 (C=CS2). 1H NMR (400.9 MHz,
˜
4
CDCl3): δ = 9.61, 8.55 (both d, JH,H = 1.5 Hz, 2 H each, 1-H, 8-
H), 7.61, 7.57 (both d, JH,H = 8.0 Hz, 2 H each, 4-H, 5-H), 7.33,
3
3
4
7.20 (both dd, JH,H = 8.0 Hz, JH,H = 1.5 Hz, 2 H each, 3-H, 6-
H), 1.67 (br. m, 6 H, CH, Cy), 1.60 (br. m, 24 H, CH2, Cy), 1.42,
1.19 (both s, 18 H each, tBu), 1.16–0.99 (br. m, 36 H, CH2, Cy)
[Cu4{S2C=(tBu-fy)}2{P(C6H4OMe-p)3}4] (5b): This yellow com-
pound was obtained as described for 5a, from [Cu(NCMe)4]PF6
(235 mg, 0.63 mmol), 1 (152 mg, 0.32 mmol), and tri-p-methoxy-
ppm. 13C{1H} NMR (75.45 MHz, CDCl3): δ = 148.9, 148.7 (C-2, phenylphosphane (227 mg, 0.64 mmol). Yield: 331 mg (89%), m.p.
C-7), 140.9 (C-8a, C-9a), 140.6 (br., CS2), 139.5 (C-8a, C-9a), 136.5,
135.8 (C-4a, C-4b), 131.7 (C-9), 123.8, 123.5, 122.9, 122.5 (C-1, C-
167 °C (dec.). IR (KBr): ν = 1498 cm–1 (C=CS2). 1H NMR
˜
4
(400.9 MHz, CDCl3): δ = 9.53 (d, JH,H = 1.4 Hz, 4 H, 1-H, 8-H),
3
8, C-3, C-6), 117.9, 117.8 (C-4, C-5), 35.1, 34.9 (CMe3), 32.1 (d, 7.63 (d, JH,H = 7.9 Hz, 4 H, 4-H, 5-H), 7.19 (m, 28 H, 3-H, 6-H
1JC,P = 16.8 Hz, C-1, Cy), 31.8, 31.6 (CMe3), 30.1 (vdd, N =
+ o-H, C6H4OMe-p), 6.24 (d, JH,H = 7.8 Hz, 24 H, m-H,
3
44.1 Hz, C-2, C-6, Cy), 27.4 (d, 3JC,P = 11.0 Hz, C-3, C-5, Cy), 25.9 C6H4OMe-p), 3.45 (s, 36 H, OMe), 1.02 (s, 36 H, tBu) ppm.
(C-4, Cy) ppm. 31P{1H} NMR (162.3 MHz, CDCl3): δ = 21.9 ppm.
C80H114Cu2P2S3 (1361.0): calcd. C 70.60, H 8.44, S 7.07; found C
70.37, H 8.63, S 7.84.
13C{1H} NMR (100.8 MHz, CDCl3): δ = 160.2 (C-4, C6H4OMe-
p), 148.0 (C-2, C-7), 141.3 (C-8a, C-9a), 135.4 (C-4a, C-4b), 135.2
2
(d, JC,P = 16.2 Hz, C-2, C-6, C6H4OMe-p), 132.6 (C-9), 125.2 (C-
1
1, C-8), 124.5 (d, JC,P = 35.0 Hz, C-1, C6H4OMe-p), 120.9 (C-3,
[Cu2{[SC=(tBu-fy)]2S}(dppf)] (4c): NEt3 (21 µL, 0.17 mmol) was
added to a suspension of 3c (160 mg, 0.16 mmol) in MeCN (8 mL)
and the mixture was stirred for 24 h. The reaction took place grad-
ually to give a brown suspension. The solvent was removed under
vacuum and the residue was stirred in CH2Cl2 (10 mL) for 7 h. The
dark-brown solution was filtered through Celite and concentrated
to about 4 mL. Addition of acetone (12 mL) led to the slow precipi-
tation of an orange solid, which was filtered off, washed with ace-
3
C-6), 117.0 (C-4, C-5), 113.9 (d, JC,P = 10.2 Hz, C-3, C-5,
C6H4OMe-p), 54.8 (OMe), 34.8 (CMe3), 31.7 (CMe3) ppm; CS2
not observed. 31P{1H} NMR (162.3 MHz, CDCl3): δ = –8.26 ppm.
C128H132Cu4P4S4 (2176.8): calcd. C 64.90, H 5.62, S 5.41; found C
64.66, H 5.68, S 5.36.
[Cu4{S2C=(tBu-fy)}2(dppf)2] (5c): This yellowish orange microcrys-
talline compound was obtained as described for 5a, from
tone (3×2 mL), and vacuum-dried to give 4c. Yield: 57 mg (51%),
[Cu(NCMe)4]PF6 (234 mg, 0.63 mmol), dithioate 1 (154 mg,
0.32 mmol), and dppf (177 mg, 0.32 mmol). The product was puri-
fied by recrystallization from CH2Cl2/acetone and dried at 60 °C
1
m.p. 200 °C (dec.). IR (Nujol): ν = 1504 cm–1 (C=CS2). H NMR
˜
4
(400.9 MHz, CDCl3): δ = 9.71, 8.69 (both d, JH,H = 1.5 Hz, 2 H
each, 1-H, 8-H), 7.77 (m, 4 H, o-H, Ph), 7.46–7.37 (m, 8 H, 4-H, for 4 h. Yield: 255 mg (78%), m.p. 198 °C (dec.). IR (KBr): ν =
˜
5-H + m-H, p-H, Ph), 7.27 (d, 3JH,H = 8.0 Hz, 2 H, 4-H, 5-H), 7.23
1490 cm–1 (C=CS2). 1H NMR (400.9 MHz, CDCl3): δ = 9.54 (d,
(dd, JH,H = 1.7, JH,H = 8.0 Hz, 2 H, 3-H, 6-H), 7.14–7.09 (m, 4 4JH,H = 1.5 Hz, 4 H, 1-H, 8-H), 7.71 (d, JH,H = 7.9 Hz, 4 H, 4-H,
H, 3-H, 6-H + p-H, Ph), 6.83 (m, 4 H, m-H, Ph), 6.52 (m, 4 H, o- 5-H), 7.46 (br., 16 H, o-H, Ph), 7.23 (dd, JH,H = 7.9, JH,H
4
3
3
3
4
=
H, Ph), 5.34 (br., 2 H, Cp), 4.22 (br., 2 H, Cp), 3.94 (br., 2 H, Cp),
3.47 (br., 2 H, Cp), 1.25, 1.24 (both s, 18 H each, tBu) ppm.
13C{1H} NMR (100.8 MHz, CDCl3): δ = 149.0, 148.6 (C-2, C-7),
1.5 Hz, 4 H, 3-H, 6-H), 7.12 (br., 8 H, p-H, Ph), 6.91 (br., 16 H,
m-H, Ph), 4.80 (br., 8 H, Cp), 3.86 (br., 8 H, Cp), 1.06 (s, 36 H,
tBu) ppm. 13C{1H} NMR (100.8 MHz, CDCl3): δ = 157.5 (app t,
3JC,P = 8.5 Hz, CS2), 148.1 (C-2, C-7), 141.1 (C-8a, C-9a), 135.8
3
140.2 (t, JC,P = 4.1 Hz, CS2), 140.0, 139.1 (C-8a, C-9a), 136.3 (C-
2
1
4a, C-4b), 134.4 (d, JC,P = 15.5 Hz, C-2, C-6, Ph), 132.4 (d, JC,P
(C-4a, C-4b), 134.3 (br., C-1, Ph), 133.9 (C-9), 133.2 (br., C-2, C-
2
3
= 38.5, C-1, Ph), 131.0 (d, JC,P = 14.5 Hz, C-2, Ph), 130.65 (C-4, 6, Ph), 129.2 (C-4, Ph), 128.2 (d, JC,P = 9.3 Hz, C-3, C-5, Ph),
3
2
Ph), 130.63 (C-9), 128.9 (C-4, Ph), 128.4 (d, JC,P = 10.4 Hz, C-3,
124.9 (C-1, C-8), 121.6 (C-3, C-6), 117.3 (C-4, C-5), 74.1 (d, JC,P
3
C-5, Ph), 128.2 (d, JC,P = 9.7 Hz, C-3, C-5, Ph), 123.7, 123.6, = 36.6 Hz, C-1, Cp), 71.6 (d, 3JC,P = 5.2 Hz, CH, Cp), 34.9 (CMe3),
123.2, 123.0 (C-1, C-8, C-3, C-6), 118.3, 117.9 (C-4, C-5), 80.2 (br. 31.9 (CMe3) ppm. 31P{1H} NMR (162.3 MHz, CDCl3): δ =
d, JC,P = 27.8 Hz, CH, Cp), 72.9 (d, JC,P = 3.4 Hz, CH, Cp), 72.7
–14.49 ppm. C112H104Cu4Fe2P4S4 (2068.1): calcd. C 65.05, H 5.07,
1
(d, JC,P = 44.1 Hz, C-1, Cp), 71.9 (d, JC,P = 9.9 Hz, CH, Cp), S 6.20; found C 65.01, H 5.22, S 6.05.
71.4 (br., CH, Cp), 34.94, 34.89 (CMe3), 31.62, 31.60 (CMe3) ppm.
[Cu4{S2C=(tBu-fy)}2(PiPr3)4] (5d): This bright-yellow microcrystal-
line compound was obtained as described for 5a, from [Cu-
(NCMe)4]PF6 (335 mg, 0.90 mmol), 1 (214 mg, 0.45 mmol), and
31P{1H} NMR (162.3 MHz, CDCl3): δ = –1.39 ppm. C78H76Cu2-
FeP2S3 (1354.5): calcd. C 69.16, H 5.66, S 7.10; found C 69.28, H
5.77, S 6.91.
PiPr3 (172 µL, 0.90 mmol). Yield: 241 mg (67%), m.p. 171 °C
1
[Cu4{S2C=(tBu-fy)}2(PPh3)4] (5a):
A
solid mixture of [Cu-
(dec.). IR (KBr): ν = 1482 cm–1 (C=CS2). H NMR (400.9 MHz,
˜
3
(NCMe)4]PF6 (239 mg, 0.64 mmol), PPh3 (177 mg, 0.67 mmol),
and 1 (163 mg, 0.34 mmol) was suspended in MeCN (15 mL) and
treated with piperidine (36 µL, 0.36 mmol). The resulting orange
suspension was stirred for 1 h, whereupon a yellow precipitate
CDCl3): δ = 9.61 (s, 4 H, 1-H, 8-H), 7.60 (d, JH,H = 7.8 Hz, 4 H,
3
4-H, 5-H), 7.18 (d, JH,H = 7.8 Hz, 4 H, 3-H, 6-H), 1.98 (m, 12 H,
CHMe2), 1.35 (s, 36 H, tBu), 1.14 (m, 72 H, CHMe2) ppm. 31P{1H}
NMR (162.3 MHz, CDCl3): δ = 22.85 ppm. C80H132Cu4P4S4
formed, which was filtered off, washed with MeCN (3×5 mL), and (1600.27): calcd. C 60.04, H 8.31, S 8.01; found C 59.86, H 8.32, S
vacuum dried to give 5a as a bright-yellow microcrystalline solid. 7.69.
124
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 115–126

Copper Complexes with (2,7-Di-tert-butylfluoren-9-ylidene)methanedithiolate
Table 5. Crystallographic data for 3a, 3c·CH2Cl2, 4a·4Me2CO, and 4c·CH2Cl2.
FULL PAPER
3a
3c·CH2Cl2
4a·4Me2CO
4c·CH2Cl2
Formula
Mol. wt.
T [K]
C58H55CuP2S2
941.62
100(2)
0.71073
orthorhombic
P212121
9.9445(5)
19.6841(9)
24.5657(12)
90
90
90
4808.7(4)
4
1.301
C57H55Cl2CuFeP2S2
1056.36
100(2)
0.71073
orthorhombic
Pbca
15.2475(4)
18.7570(5)
35.9456(11)
90
C92H102Cu2O4P2S3
1556.94
133(2)
C79H78Cl2Cu2FeP2S3
1439.36
133(2)
0.71073
monoclinic
P21/n
16.998(2)
18.785(2)
21.544(2)
90
96.539(4)
90
6834.8(13)
4
1.399
1.087
0.0558
λ [Å]
0.71073
Cryst syst
Space group
a [Å]
b [Å]
c [Å]
α [°]
β [°]
triclinic
¯
P1
13.901(2)
17.245(2)
18.922(2)
103.664(5)
96.463(5)
100.832(5)
4270.0(9)
2
1.211
0.657
0.0495
0.1372
90
90
γ [°]
V [Å3]
Z
10280.3(5)
8
1.365
0.980
0.0584
ρcalcd. [Mgm–3]
µ [mm–1]
0.646
0.0414
0.1046
[a]
R1
[b]
wR2
0.1321
0.1374
[a] R1 = Σ||Fo| – |Fc||/Σ|Fo| for reflections with I Ͼ 2σ(I). [b] wR2 = {Σ[w(Fo – Fc2)2]/Σ[w(Fo ) ]}0.5 for all reflections; w–1 = σ2(F2) + (aP)2 +
2
2 2
bP, where P = (2Fc + Fo2)/3 and a and b are constants set by the program.
2
(Pr4N)2[Cu{S2C=(tBu-fy)}2] [(Pr4N)26]:
A
previously degassed
H, 4-H, 5-H + PPN+), 7.56–7.51 (m, 12 H, PPN+), 7.28 (dd, 4JH,H
= 1.7, JH,H = 8.0 Hz, 4 H, 3-H, 6-H), 1.38 (s, 36 H, tBu) ppm.
3
1.0  solution of (Pr4N)OH in water (0.60 mL, 0.60 mmol) and a
solution of Cu(ClO4)2·6H2O (85 mg, 0.23 mmol) in MeCN (5 mL)
were added successively to a solution of 1 (234 mg, 0.49 mmol) in
MeCN (10 mL). Reaction was observed to give a dark-brown sus-
pension, which was stirred for 5 min. The supernatant was de-
canted and the precipitate was washed with MeCN (3×5 mL) and
vacuum-dried to give (Pr4N)26 as a brown powder. Yield: 208 mg
13C{1H} NMR [75.5 MHz, (CD3)2CO]: δ = 154.3 (CS2), 149.6 (C-
2, C-7), 140.3 (C-8a, C-9a), 135.7 (C-4a, C-4b), 128.2 (C-9), 122.7
(C-3, C-6), 120.7 (C-1, C-8), 119.1 (C-4, C-5), 35.4 (CMe3), 32.1
(CMe3) ppm. C80H78CuNS4 (1245.3): calcd. C 73.50, H 6.01, N
1.07, S 9.81; found: C 73.50, H 5.80, N 1.10, S 9.52.
(79%), m.p. 237 °C (dec.). IR (KBr): ν = 1480 cm–1 (C=CS2).
X-ray Structure Determinations: Crystals of 3a, 3c·CH2Cl2,
4a·4Me2CO, and 4c·CH2Cl2 suitable for X-ray diffraction studies
were obtained from chloroform/pentane (3a), CH2Cl2/hexane (3e),
acetone/hexane (4a), or CH2Cl2/pentane (4c). Numerical details are
presented in Table 5. The structures of 3a and 3c were measured
on a Bruker Smart APEX diffractometer, and those of 4a and 4c
on a Bruker SMART 1000 CCD diffractometer. Data were col-
lected using monochromated Mo-Kα radiation in ω-scan mode.
The structures were solved by direct methods and refined aniso-
tropically on F2 using the program SHELXL-97 (G. M. Sheldrick,
University of Göttingen, Germany). Restraints to local aromatic
ring symmetry or light-atom displacement factor components were
applied in some cases. The methyl groups were refined using rigid
groups, and the other hydrogen atoms were refined using a riding
model. Special features of refinement: For compound 3a, the Flack
parameter is 0.047(10). For compounds 3c, 4a, and 4c the Me
groups of one tBu group are disordered over two positions. The
solvent in the crystals of 4a was so badly resolved that no sensible
refinement model could be developed. For this reason the program
SQUEEZE (A. L. Spek, University of Utrecht, Netherlands) was
used to remove the effects of the solvent mathematically. The sol-
vent content of four acetone molecules is only an approximate esti-
mate. The dichloromethane molecule in 4c is disordered over two
positions.
˜
C68H104CuN2S4 (1141.4): calcd. C 71.56, H 9.18, N 2.45, S 11.24;
found C 71.36, H 9.23, N 2.50, S 11.45.
Pr4N[Cu{S2C=(tBu-fy)}2] (Pr4N7):
A solution of 1 (607 mg,
1.27 mmol) in MeCN (15 mL) was treated successively with a 1.0 
solution of (Pr4N)OH in water (1.4 mL, 1.4 mmol) and Cu-
(ClO4)2·6H2O (228.7 mg, 0.617 mmol). The resulting brown sus-
pension was stirred for 2.5 h under atmospheric conditions, where-
upon a green precipitate formed, which was filtered off, washed
with MeCN (3×3 mL), and vacuum-dried to give Pr4N7. Yield:
544 mg (92%), m.p. 233 °C (dec.). IR (Nujol): ν = 1548 cm–1
˜
1
(C=CS2), 416 (Cu–S). H NMR [400.9 MHz, (CD3)2CO]: δ = 8.46
(d, JH,H = 1.3 Hz, 4 H, 1-H, 8-H), 7.68 (d, JH,H = 8.0 Hz, 4 H,
4
3
3
4
4-H, 5-H), 7.29 (dd, JH,H = 8.0, JH,H = 1.7 Hz, 4 H, 3-H, 6-H),
3.31 (m, 8 H, NCH2), 1.78 (m, 8 H, CH2), 1.39 (s, 36 H, tBu),
0.95 (t, JH,H = 7.2 Hz, 12 H, Me, Pr4N+) ppm. 13C{1H} NMR
3
[75.5 MHz, (CD3)2CO]: δ = 154.1 (CS2), 149.6 (C-2, C-7), 140.2
(C-8a, C-9a), 135.7 (C-4a, C-4b), 128.2 (C-9), 122.8 (C-3, C-6),
120.7 (C-1, C-8), 119.2 (C-4, C-5), 35.4 (CMe3), 32.1 (CMe3) ppm.
C56H76CuNS4 (955.03): calcd. C 70.43, H 8.02, N 1.47, S 13.43;
found C 70.66, H 8.29, N 1.50, S 13.79.
PPN[Cu{S2C=(tBu-fy)}2] (PPN7): Piperidine (46 µL, 0.46 mmol)
and CuCl2·2H2O (34 mg, 0.20 mmol) were added successively to a
solution of 1 (212 mg, 0.45 mmol) and PPNCl (130 mg, 0.23 mmol)
in MeCN (15 mL). The resulting red solution was stirred for 1 h
under atmospheric conditions, after which time a green solid pre-
cipitated. The product was filtered off, washed with ethanol
(3×2 mL) and diethyl ether (2 mL), and vacuum-dried to give
CCDC-277675 (3a) -277674 (3c·CH2Cl2), -277676 (4a·4Me2CO),
and -277673 (4c·CH2Cl2) contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
PPN7. Yield: 184 mg (63%), m.p. 238 °C (dec.). IR (Nujol): ν =
˜
1552 cm–1 (C=CS2), 420 (Cu–S). 1H NMR [400.9 MHz, (CD3)2- Supporting Information (see footnote on the first page of this arti-
4
CO]: δ = 8.46 (d, JH,H = 1.4 Hz, 4 H, 1-H, 8-H), 7.72–7.65 (m, 22 cle): Positive ion FAB mass spectra of 5a–d.
Eur. J. Inorg. Chem. 2006, 115–126
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
125

J. Vicente, P. González-Herrero, Y. García-Sánchez, P. G. Jones, D. Bautista
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Received: July 11, 2005
Published Online: November 11, 2005
126
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Eur. J. Inorg. Chem. 2006, 115–126