Platinum complexes of aromatic selenolates

Article abstract of DOI:10.1002/ejic.201000357

Several synthetic methods are used to prepare naphthalene based aromatic 1,2-diselenoles. A new one-pot synthesis starting from naphthalene is used to produce the known compound naphtho[1,8-c,d][1,2]diselenole (Se₂naph). Friedel-Crafts alkylation is used on Se₂naph to substitute either one tert-butyl group to form 2-tert-butylnaphtho[1,8-c,d][1,2]diselenole (mt-Se₂naph) or two tert-butyl groups to form 2,7-di-tert- butylnaphtho[1,8-c,d][1,2]diselenole (dt-Se₂naph). Bromination of mt-Se₂naph results in dibromination of the naphthalene ring, rather than reaction at selenium, to give 4,7-dibromo-2-tert-butylnaphtho[1,8-c,d][1,2] -diselenole (mt-Se₂naphBr₂). Reduction of the Se-Se bond in Se₂naph, mt-Se₂naph, dibenzo[c,e][1,2]diselenine (dibenzSe₂), or diphenyl diselenide (Se₂Ph₂) with LiBEt₃ H, followed by in-situ addition of [PtCl ₂{P(OPh)₃}₂] yields the fourcoordinate mono-and dinuclear platinum(II) bis(phosphite) complexes [Pt(Se₂naph){P(OPh) ₃}₂] (1), [Pt(mt-Se₂naph)-{P(OPh) ₃}₂] (2), [Pt₂(dibenzSe₂) ₂{P(OPh)₃}₂] (3), cis-[Pt(SePh) ₂-{P(OPh)₃}₂] (4), and trans-[Pt ₂(SePh)₄{P(OPh)₃}₂] (5).

Full text of DOI:10.1002/ejic.201000357

FULL PAPER
DOI: 10.1002/ejic.201000357
Platinum Complexes of Aromatic Selenolates
Amy L. Fuller,[a] Fergus R. Knight,[a] Alexandra M. Z. Slawin,[a] and J. Derek Woollins*[a]
Keywords: Platinum / Selenium / Heterocycles
Several synthetic methods are used to prepare naphthalene-
based aromatic 1,2-diselenoles. A new one-pot synthesis
starting from naphthalene is used to produce the
known compound naphtho[1,8-c,d][1,2]diselenole (Se2naph).
Friedel–Crafts alkylation is used on Se2naph to substitute
either one tert-butyl group to form 2-tert-butylnaphtho[1,8-
nium, to give 4,7-dibromo-2-tert-butylnaphtho[1,8-c,d][1,2]-
diselenole (mt-Se2naphBr2). Reduction of the Se–Se bond in
Se2naph, mt-Se2naph, dibenzo[c,e][1,2]diselenine (di-
benzSe2), or diphenyl diselenide (Se2Ph2) with LiBEt3 H, fol-
lowed by in-situ addition of [PtCl2{P(OPh)3}2] yields the four-
coordinate mono- and dinuclear platinum(II) bis(phosphite)
c,d][1,2]diselenole (mt-Se2naph) or two tert-butyl groups to complexes [Pt(Se2naph){P(OPh)3}2] (1), [Pt(mt-Se2naph)-
form 2,7-di-tert-butylnaphtho[1,8-c,d][1,2]diselenole (dt-
Se2naph). Bromination of mt-Se2naph results in dibromina-
tion of the naphthalene ring, rather than reaction at sele-
{P(OPh)3}2] (2), [Pt2(dibenzSe2)2{P(OPh)3}2] (3), cis-[Pt(SePh)2-
{P(OPh)3}2] (4), and trans-[Pt2(SePh)4{P(OPh)3}2] (5).
oped a facile, “one-pot” synthesis for Se2naph. We have in-
vestigated substitution of this ring using Friedel–Crafts
alkylation and report the synthesis of 2,7-di-tert-butyl-
naphtho[1,8-c,d][1,2]diselenole (dt-Se2naph) and 2-tert-
butylnaphtho[1,8-c,d][1,2]diselenole (mt-Se2naph). Reaction
of mt-Se2naph with bromine gives 4,7-dibromo-2-tert-butyl-
naphtho[1,8-c,d][1,2]diselenole (mt-Se2naphBr2) (Figure 2).
Introduction
The first synthesis of naphtho[1,8-c,d][1,2]diselenole
(Se2naph) was reported in 1977 by Meinwald et al. (Fig-
ure 1).[1] In their work, Se2naph was synthesized by adding
two equivalents of selenium powder to dilithionaphthalene
and then exposing the reaction mixture to air to obtain the
desired product in 18–22% yield. Today this preparation is
still the most referenced procedure for making this com-
pound. In 1988, Yui et al. reported a different synthetic
route to Se2naph, which involves the addition of sodium
diselenide (Na2Se2) to 1,8-dichloronaphthalene, producing
Se2naph in a 69% yield.[2] Others have started with 1,8-di-
bromonaphthalene, synthesized 1,8-dilithionaphthalene,
then added elemental selenium (as in Meinwald et al.’s pro-
cedure); however, low yields are reported (16%).[3] These
reported procedures are, in reality, quite lengthy and pres-
ent a number of synthetic hurdles, i.e. lengthy synthesis of
1,8-dichloro-[4] or 1,8-dibromonaphthalene.[5]
Figure 2.
2,7-di-tert-butylnaphtho[1,8-c,d][1,2]diselenole
(dt-
Se2naph), 2-tert-butylnaphtho[1,8-c,d][1,2]diselenole (mt-Se2naph),
and 4,7-dibromo-2-tert-butylnaphtho[1,8-c,d][1,2]diselenole (mt-
Se2naphBr2).
The crystal structure of Se2naph has previously been re-
ported,[7] along with several other compounds having an
Se–Se bond; such as dibenzo[c,e][1,2]diselenine (dibenzSe2)
and diphenyl diselenide (Se2Ph2) (Figure 3).[8,9] Similar
backbones in each of these compounds produce similar
chemical environments for the selenium atoms. Although
the compounds are structurally similar around the selenium
atoms, there are major differences in the conformation that
the backbone forces on the selenium substituents. As a re-
sult, the Se–Se bond length varies as a function of the flexi-
Figure 1. Naphtho[1,8-c,d][1,2]diselenole (Se2naph).
In 1994, a synthetic procedure for the sulfur analog,
naphtho[1,8-c,d][1,2]dithiole (S2naph) was published using
unsubstituted naphthalene as a starting material.[6] We have
extended that synthesis to the selenium system and devel-
[a] School of Chemistry, University of St Andrews,
St Andrews, Fife KY16 9ST, UK
E-mail: jdw3@st-and.ac.uk
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Platinum Complexes of Aromatic Selenolates
bility of the diaryl backbone. Se2naph has the longest Se–Se
To date, there is only one reported “series” of related
bond length at 2.3639(5) Å, followed by dibenzo[c,e][1,2]- complexes. This series contains platinum bis-triphenylphos-
diselenine (benzSe2) [2.323(2) Å], and then diphenyl diselen- phane complexes with the general formula LPt(PPh3)2,
ide (Se2Ph2) [2.29(1) Å]. The direct relationship that can be where L is Se2naph, dibenzSe2, or two molecules of SePh
drawn is the more rigid the backbone, the longer the Se–Se (Figure 5). These complexes were not synthesized in a single
bond.
laboratory, but have been reported independently by several
groups. [Pt(PPh3)2(Se2naph)], [Pt(PPh3)2(dibenzSe2)], and
cis-[Pt(PPh3)2(SePh)2] were obtained via oxidative addition
reactions with [Pt(PPh3)4] and the respective neutral dis-
elenium compound.[10,11,14] These complexes are very sim-
ilar around the PtII metal center despite the flexibility of
the backbone.
Figure 3. a: Naphtho[1,8-c,d][1,2]diselenole (Se2naph), b: dibenzo-
[c,e][1,2]diselenine (dibenzSe2), and c: diphenyl diselenide (Se2Ph2).
These compounds can be used as ligands, by reducing
the Se–Se bond to form dianionic Se2naph or dibenzSe2
or monoanionic SePh (the reduced, negatively charged
ligands are indicated by italics). There are very few
metal complexes reported that have Se2naph (or any naph-
thalene derivative) or dibenzSe as a ligand. These are
limited to the platinum(II) bis(phosphane) complexes, [Pt-
(Se2naph)(PPh3)2], [Pt(Se2naph)(PMe3)2], and [Pt(dibenzSe2)-
(PPh3)2].[10,11] Furthermore, there are only a few reported
mononuclear square-planar complexes having two SePh li-
gands. These include cis- and trans-[Pt(SePh)2(PPh3)2],
trans-[Pt(SePh)2{P(nBu)3}2], and trans-[Pt(SePh)2(PEt3)2].
Not only does SePh form mononuclear complexes, but
there are several examples of the formation of dinuclear
complexes with SePh moieties bridging the two metal cen-
ters (Figure 4).[11–13]
Figure 5. a: [Pt(PPh3)2(Se2naph)], b: [Pt(PPh3)2(dibenzSe2)], and c:
cis-[Pt(PPh3)2(SePh)2].
In order to expand the number of di-selenium containing
complexes and to obtain a series of these types of platinum
complexes from which to draw structural insights, we have
synthesized and characterized a new group of complexes
produced by reactions using cis-[PtCl2{P(OPh)3}2] as a
starting material. The resulting four-coordinate mono-
and di-nuclear platinum(II) bis-phosphite complexes are
[Pt(Se2naph){P(OPh)3}2] (1), [Pt(mt-Se2naph){P(OPh)3}2]
(2), [Pt2(dibenzSe2)2{P(OPh)3}2] (3), cis-[Pt(SePh)2{P-
(OPh)3}2] (4), and trans-[Pt2(SePh)4{P(OPh)3}2] (5) (Fig-
ure 6). The X-ray structures of these compounds are re-
ported along with a detailed comparison of their structures
focusing on the geometry around the PtII metal center.
Figure 4. Known dinuclear complexes with bridging SePh ligands.
Figure 6. Complexes reported in this work: [Pt(Se2naph){P(OPh)3}2] (1), [Pt(mt-Se2naph){P(OPh)3}2] (2), [Pt2(dibenzSe2)2{P(OPh)3}2] (3),
cis-[Pt(SePh)2{P(OPh)3}2] (4) and trans-[Pt2(SePh)4{P(OPh)3}2] (5).
Eur. J. Inorg. Chem. 2010, 4034–4043
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A. L. Fuller, F. R. Knight, A. M. Z. Slawin, J. D. Woollins
FULL PAPER
Results and Discussion
Several useful ligands have been prepared by novel syn-
thetic methods in the course of this research. Naphtho[1,8-
c,d][1,2]diselenole (Se2naph) is synthesized using a one-pot
reaction starting from naphthalene (26% yield). This syn-
thesis was modelled after one reported by Ashe et al. for
the sulfur analog naphtho[1,8-c,d][1,2]dithiole.[6] It was also
found that substitution of the naphthalene ring in Se2naph
with either one tert-butyl group to form 2-tert-butylnaph-
tho[1,8-c,d][1,2]diselenole (mt-Se2naph) or two tert-butyl
groups to form 2,7-di-tert-butylnaphtho[1,8-c,d][1,2]diselen-
ole (dt-Se2naph) was possible via a standard Friedel–Crafts
alkylation.[7,15] The addition of dibromine to mt-Se2naph
gave no reaction between selenium and bromine. Instead,
electrophilic aromatic substitution dominates to produce
the doubly substituted compound 4,7-dibromo-2-tert-
Figure 7. The 77Se NMR for mt-Se2naph.
butylnaphtho[1,8-c,d][1,2]diselenole
(mt-Se2naphBr2)
X-ray structural characterization was conducted for dt-
Se2naph and mt-Se2naphBr2 (Table 1, Figure 8), however,
mt-Se2naph is a persistent oil and could not be crystallized.
(Scheme 1). This is unusual, since reacting organoselenium
compounds with dibromine generally results in oxidative
addition with addition of the dibromine to the selenium
atom, which adopts a “T-shaped” geometry.[16–18]
Table 1. Selected interatomic distances [Å] and angles [°] for dt-
Se2naph and mt-Se2naphBr2.
dt-Se2naph[a]
mt-Se2naphBr2
Se(1)–Se
Se(1)–C(1)
Se(2)–C(9)
2.3383(5)
1.934(3)
2.3388(14)
1.935(9)
1.888(9)
Se(1)–Se(2)–C(9)
Se(2)–Se(1)–C(1)
Se(1)–C(1)–C(2)
Se(1)–C(1)–C(10)
Se(2)–C(9)–C(8)
Se(2)–C(9)–C(10)
C(2)–C(1)–C(10)
C(10)–C(9)–C(8)
C(1)–C(10)–C(9)
90.9(3)
93.9(2)
93.16(10)
122.4(2)
113.2(2)
Scheme 1. The reaction scheme for the preparation of 4,7-dibromo-
2-tert-butylnaphtho[1,8-c,d][1,2]diselenole (mt-Se2naphBr2).
122.0(7)
114.4(6)
121.6(7)
119.1(7)
123.6(8)
119.3(8)
121.7(8)
The bromine selectivity can be explained by the elec-
tronic directing influence of selenium and the steric bulk of
the tert-butyl group. Both selenium and tert-butyl groups
donate electrons into the π-system, activating the naphth-
alene ring and directing incoming electrophiles to the ortho
or para positions. The first attack at the position para to
selenium would be sterically more favorable, keeping the
two large bromine and tert-butyl groups further apart.
However, the second substitution reaction is directed to the
ortho position on the second ring to avoid the steric interac-
tion with the first bromine atom.
124.3(3)
124.8(3)
C(4)–C(5)–C(10)–C(1)
C(6)–C(5)–C(10)–C(9)
C(4)–C(5)–C(10)–C(9)
C(6)–C(5)–C(10)–C(1)
–0.9(2)
–0.9(2)
179.1(2)
179.1(2)
–1.0(5)
–1.0(5)
180.0(10)
180.0(10)
Mean plane deviations
Se(1)
Se(2)
–0.1989(57)
–3.2451(39)
–3.3015(40)
A unique characteristic of these compounds is the sele-
nium NMR spectroscopy. These compounds are made up
of 77SeSe, Se77Se, and 77Se77Se isotopomers. Any selenium
sample is a mixture of several stable isotopes, but only 77Se,
[a] Se(2) is Se(1A), C(10) is C(6), C(9) is C(1A) and C(6) is
C(4A)Ј.
The Se–Se bond lengths of dt-Se2naph [2.3383(5) Å] and
natural abundance of 7%, is NMR active. When the sele- mt-Se2naphBr2 [2.3388(14) Å] are almost identical, but they
nium atoms are in different chemical environments, the 77Se are shorter than in Se2naph, [2.3639(5) Å].[7] In dt-Se2naph
NMR contains two major signals. For example, in mt- the selenium atoms are forced out of the plane, but this
Se2naph, the first two isotopomers give rise to singlets cen- does not occur in Se2naph or mt-Se2naphBr2. Despite the
tered at 414 and 360 ppm, whilst the latter gives an AX deviation from planarity of dt-Se2naph, a comparison of
spectrum with JSe-Se = 345 Hz (Figure 7). The peak at δ = torsion angles around the bridgehead carbon atoms of the
360 ppm corresponds to the selenium atom closest to the backbone reveals little variation between Se2naph, dt-
tert-butyl group, based on comparison to the 77Se spectra Se2naph and mt-Se2naphBr2 (Figure 9).
of Se2naph (δ = 420 ppm) and dt-Se2naph (δ = 353 ppm).
The crystal packing in Se2naph, dt-Se2naph and mt-
The 77Se NMR spectrum of mt-Se2naphBr2, is similar, Se2naphBr2 shows significant differences. Se2naph forms
showing two shifts at 454 and 374 ppm, however, the peaks herringbone π-stacks that are linked by an Se···Se interac-
were broad and the JSe-Se could not be determined.
tion, with a π-π distance between naphthalene rings on
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Platinum Complexes of Aromatic Selenolates
Figure 10. View of crystal packing in mt-Se2naphBr2 along the b-
axis.
(2), [Pt2(dibenzSe2)2{P(OPh)3}2] (3), cis-[Pt(SePh)2{P-
(OPh)3}2] (4), and trans-[Pt2(SePh)4{P(OPh)3}2] (5).
Scheme 2 shows the reaction to form 1 and 2.
Figure 8. Molecular representation of mt-Se2naph (top) and mt-
Se2naphBr2 (bottom).
Scheme 2. Synthesis of 1 and 2.
Complexes 1 and 2 have been fully characterized by ele-
1
mental analysis, MS, IR, Raman, and H, 13C, 31P, 77Se,
and 195Pt NMR spectroscopy. We were unable to isolate
bulk samples of complexes 3–5 and these complexes have
been characterized by X-ray crystallography and multinu-
clear NMR spectroscopy.
Figure 9. Out-of-plane deflections of a) Se2naph, b) dt-Se2naph,
and c) mt-Se2naphBr2.
The 31P, 77Se, and 195Pt NMR spectroscopic data for 1–
5 are given in Table 2 In its 31P NMR spectrum, 1 displays
separate molecules of 3.81 Å.[7] However, due to the bulky a singlet at δ = 87 ppm, and both platinum (JP,Pt = 4711 Hz)
tert-butyl arms, there are no intermolecular interactions be- and selenium (JP-Se = 28 Hz) satellites are visible. The 77Se
tween Se atoms in the crystal packing of dt-Se2naph. In mt- NMR contains a peak at δ = 140 ppm (JSe-P = 28 Hz)
Se2naphBr2, there is no intermolecular Se···Se interaction, (JSe-Pt = 205 Hz). The 195Pt NMR displays a triplet centered
however, there is a close intermolecular Br(4)···Br(8)Ј con- at –4711 ppm with selenium satellites visible (JPt,P
tact [3.4790(13) Å]. This interaction and the resulting pack- 4711 Hz) (JPt-Se = 205 Hz).
ing, is illustrated in Figure 10.
=
The 31P NMR spectrum for 2 displays a typical [ABX]-
Reduction of the Se–Se bond in Se2naph, mt-Se2naph, or pattern (A = PIII, X = Pt) indicative of direct coordination
dibenzo[c,e][1,2]diselenine (dibenzSe2) forms the dianion of of two inequivalent phosphorus atoms to the platinum cen-
those species {the presence of which, is denoted by italics ter. Both signals have platinum and selenium satellites; δ =
in a molecular formula, e.g. [Pt(mt-Se2naph)(P(OPh)3)2]}. 89 (JP-P = 68 Hz) (JP,Pt = 4686 Hz) (JP-Se = 19, 28); δ = 86
The analogous reduction of diphenyl diselenide (Se2Ph2) (JP-P = 68 Hz) (JP,Pt = 4669 Hz) (JP-Se = 35 Hz). The 77Se
gives monoanionic SePh (also indicated by italics). Forma- NMR of 2 consists of two signals, each split by two inequiv-
tion of the anion is followed by in situ addition of alent phosphorus atoms into a doublet of doublets with
[PtCl2{P(OPh)3}2], which yield the four-coordinate mono- platinum satellites. The upfield peak at δ = 138 ppm is as-
and di-nuclear platinum(II) bis-phosphite complexes signed to the 77Se furthest from the tert-butyl arm by com-
[Pt(Se2naph){P(OPh)3}2] (1), [Pt(mt-Se2naph){P(OPh)3}2] parison with 1. The 195Pt NMR displays an apparent triplet
Eur. J. Inorg. Chem. 2010, 4034–4043
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A. L. Fuller, F. R. Knight, A. M. Z. Slawin, J. D. Woollins
FULL PAPER
Table 2. NMR[a] data for complexes 1–5.
1
2[b]
2[c]
3
4/5
δ = 31P
[ppm]
87
89
86
85
84
JP-P [Hz]
JP,Pt [Hz]
JP-Se [Hz]
68
4686
19, 28
68
4669
35
4711
28
4685
21
4724
28
δ = 77Se
JSe-P [Hz]
JSe-Pt [Hz]
140 (t)
28
205
258 (dd) 138 (dd) 225 (t)
222 (t)
28
188
19, 35
327
7, 28
212
21
183
–4575
(dd)
4979
δ = 195Pt
–4711 (t)
–4570 (t) –4075
JPt,P [Hz]
JPt-Se [Hz]
4711
205
4685
183
4729
[a] All NMR samples were prepared from crystalline samples in
CDCl3. [b] In complex 2, two signals result from the 77Se atom
present in one of two inequivalent positions, either the position
closest to or furthest away from the substituted tert-butyl arm. At
this time, based on comparisons to complex 1, it is thought that
the 77Se peak at δ = 138 ppm corresponds to the 77Se atom furthest
from the tert-butyl substituent. [c] See footnote [b].
(doublet of doublets with similar coupling constants) cen-
tered at –4575 ppm (JPt,P ≈ 4680 Hz).
The NMR spectroscopic data for 3 indicates the mono-
nuclear complex [Pt(dibenzSe2){P(OPh)3}2] is the predomi-
nant species in solution.[19] The 31P NMR for 3 displays a
typical [AX]-pattern relating to the direct coordination of
two equivalent phosphorus atoms to the platinum center
and selenium satellites are also observed; δ = 85 (JP,Pt
4685 Hz) (JP-Se = 21). The 77Se NMR displays a triplet with
platinum satellites at δ = 225 (JSe-P = 21 Hz) (JSe-Pt
183 Hz). The 195Pt NMR spectrum displays a triplet cen-
tered at –4570 ppm with selenium satellites visible (JPt,P
=
=
=
4685 Hz) (JPt-Se = 183 Hz). We were unable to separate 4
and 5 and the 31P, 77Se, and 195Pt NMR spectra were mea-
sured using samples that contained crystalline material of
at least some crystals of both complexes, as determined by
X-ray studies. The NMR spectroscopic data, however, are
indicative of the presence in solution of just compound 4.
The 31P NMR spectrum displays a typical [AAX]-pattern
with a single signal at δ = 85 ppm with platinum satellites
(JP,Pt = 4724 Hz). As in 3, the 77Se NMR spectrum of 4/5
Figure 11. Molecular representations of the core atoms in 1 (top),
2 (middle), and one molecule of 4a (bottom).
exhibits a triplet with platinum satellites; δ = 222 (JSe-P
=
28 Hz) (JSe-Pt = 188 Hz). The 195Pt NMR spectrum displays
a triplet centered at –4075 ppm (JPt,P = 4729 Hz).
The X-ray crystal structures of 1, 2, and 4a are shown in structure of 4, however, this same solution also yielded crys-
Figure 11, while Figure 12 shows 3 and 5. The X-ray analy- tals of binuclear 5.
ses show that in every complex, the platinum center lies in
Complexes 1, 2, and 4 have strong similarities. Selected
a distorted square-planar environment.
bond lengths and angles can be found in Table 3. Each of
The differing molecular structures of 4 and 5 were quite these complexes is monomeric, containing a four-coordi-
unexpected. As described above, the 31P NMR clearly sug- nate PtII center having two –P(OPh)3 ligands and two sele-
gest that only one species is present in the solution after nium ions from one or more of the selenium containing
synthesis and purification of the reaction mixture. Crystalli- ligands. A comparison of bond lengths within this series of
zation using pentane diffusion into a dichloromethane solu- mononuclear complexes shows that all of these complexes
tion produced orange block crystals, which were charac- have very similar Pt–P bond lengths ranging from
terized by X-ray crystallography, revealing the monomeric 2.2232(13) Å to 2.2390(16) Å, with complex 2 having the
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Platinum Complexes of Aromatic Selenolates
Table 3. Selected interatomic distances [Å] and angles [°] for 1, 2,
and 4 (41 is the second independent molecule of 4).
1
2
4
41
Pt(1)–Se(1)
Pt(1)–Se(2)
Pt(1)–P(1)
Pt(1)–P(2)
Se(1)–C(1)
Se(2)–C
2.4600(7) 2.4356(5) 2.474(2)
2.4527(7) 2.4256(5) 2.463(2)
2.2390(16) 2.2232(13) 2.229(5)
2.2324(14) 2.2385(14) 2.224(4)
2.481(2)
2.481(2)
2.235(5)
2.235(5)
1.87(2)
1.921(6)
1.924(6)
1.914(5)
1.930(4)
1.85(2)
1.94(2)
Se(1)–Pt(1)–Se(2) 85.55(2)
89.43(8)
Se(1)–Pt(1)–P(1)
Se(2)–Pt(1)–P(2)
P(1)–Pt(1)–P(2)
Se(1)–Pt(1)–P(2)
Se(2)–Pt(1)–P(1)
91.19(4)
88.80(4)
94.67(6)
169.82(5) 176.93(3) 86.50(13) 86.11(15)
176.33(4) 175.08(3) 93.73(13) 86.11(15)
Pt(1)–Se(1)–C(1) 100.17(17) 107.59(13) 110.3(6)
Pt(1)–Se(2)–C 107.63(18) 116.77(15) 112.8(5)
105.0(6)
105.0(6)
pushes the selenium atom nearest to it out of the plane of
the naphthalene ring, rendering the Se–Pt–Se bond angle
larger than in 1, where the selenium atoms may be con-
strained by a need to stay in the plane of the rings to par-
ticipate in π-resonance. However, the size of the Se(1)–
Pt(1)–Se(2) bond angle in 4 falls in the middle of the series
of complexes, despite not being restricted by the backbone,
as in 1 and 2. The similarity of the bond angle (only ca. 4°
difference) amongst the complexes is likely not coincidental,
even if the ligands have no strong geometric preferences, the
geometry of the complex is still limited by the tendency of
PtII to be square planar.
Compared to 4 in the Se–Pt–Se angles, the cis-bond
angles Se–Pt–P in the three complexes are universally sim-
ilar. The Se(1)–Pt(1)–P(2) bond angle in 4 is 86.50(13)° and
the Se(2)–Pt(1)–P(1) bond angle is 93.73(13)° with the
Se(1)–Pt(1)–P(1) bond angle being 91.19(4)° and the Se(2)–
Pt(1)–P(2) bond angle being 88.80(4)°. The bond angle dif-
ferences in 2 are similar to the other two complexes, with
the Se(1)–Pt(1)–P(1) bond angle being 86.94(3)° and the
Se(2)–Pt(1)–P(2) bond angle being 88.02(4)°. The two trans
Se–Pt–P bond angles of the three complexes likewise differ
Figure 12. Molecular representations of 3 (top) and 5 (bottom).
shortest Pt–P bond length. The Pt–Se bond lengths have a from each other by only a few degrees. The difference be-
larger difference. The Pt–Se bond lengths are longest in tween the two angles is 7.5° in 1, 4.2° in 4 and 1.8° in 2.
4/4a ranging from 2.481(2) Å to 2.463(2) Å, slightly shorter
The smallest of the trans Se–Pt–P bond angles occurs in
in 1 at 2.4600(7) Å and 2.4527(7) Å, and yet shorter in 2 at 1, with an angle of 169.82(5)°. Other than a bond angle of
2.4356(5) Å and 2.4256(5) Å. The short Pt–Se distances in 173.40(14)° in 4, all the other trans bond angles in all three
2 are possibly an effect of the electron donating tert-butyl complexes are very close to 176°. Like all the other angles,
arm on the naphthalene ring. It is noticeable on going from the P(1)–Pt(1)–P(2) bond angles of 1, 2, and 4 are very sim-
1 to 2 the six membered PtSe2C3 ring changes substantially. ilar, except in 4b, where it is the largest by 4° at 99.3(2)°.
In 1 the ring is essentially a boat conformation with a hinge Somewhat strangely, the steric strain presented by the tert-
at the Se···Se vector whilst in 2 the ring is a twisted chair butyl group in 2 and the greater degree of freedom allowed
conformation this difference presumably arises as a conse- by the lack of a constraining background in 4 do not seem
quence of the sterically demanding tert-butyl group in 2.
to cause much variation in the structure around the metal
The Se(1)–Pt(1)–Se(2) bond angles increase from center. The metal center appears to be dictating the geome-
85.55(2)° in 1, to 87.47(7)° in 4 to 89.43(8)° in 4a, and fi- try and forcing the ligands to arrange themselves so that
nally to 89.885(17)° in 2. It is interesting that the only dif- the complex has as close to a square planar motif it can.
ference between 1 (the smallest angle) and 2 (the largest
Complexes 3 and 5 are different from the three just dis-
angle) is the substitution of the tert-butyl substituent on the cussed, in that they each crystallize as a dinuclear complex
naphthalene ring. The steric bulk of the tert-butyl group with two four-coordinate PtII metal centers in a diamond
Eur. J. Inorg. Chem. 2010, 4034–4043
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4039

A. L. Fuller, F. R. Knight, A. M. Z. Slawin, J. D. Woollins
FULL PAPER
core motif. Each PtII ion in both complexes is coordinated bond lengths are similar at ca. 2.20 Å in 3 and ca. 2.19 Å in
by three selenium ions and one –P(OPh)3 ligand. A list of 5. The Pt–Se bonds in both complexes differ depending on
selected bond lengths and angles for 3 and 5 are shown in whether they are coordinated in a terminal or bridging
Tables 4 and 5. The difference between the two coordina- fashion, but are again markedly similar between the two
tion spheres is that 3 has dianionic bis-selenium ligands complexes. In 3, the terminal Pt–Se bond lengths are
based on the biphenyl backbone, while the platinum centers ≈ 2.44 Å, whereas the bridging bond lengths are
in 5 are ligated by individual SePh ligands. One of the sele- about 2.46 Å. In 5, the terminal Pt–Se bond lengths are
nium atoms on the biphenyl in 3 is in a bridging position, ca. 2.45 Å, and the bridging bond lengths are ca. 2.47 Å.
which forces the ligand to twist and strain in order for the
Like the bond lengths, the bond angles in 3 and 5 are
platinum to coordinate the other selenium atom. In 5, the very similar. Complex 3 has two obtuse angles and two
bridging and terminal positions are occupied by the SePh acute angles around the platinum centers, which form a flat-
ligands instead.
tened X with a platinum atom in the center. The Se–Pt–Se
bond angle of the diamond core is 83.89(3)°, and the bond
trans to this, across the platinum center, is 88.50(7)°. The
other two angles around the platinum center are ca. 94°.
The Pt–Se–Pt bond bridging the diamond core is 96.04(3)°.
The bond angles in 5 track very closely to those in 3.
The Se–Pt–Se bond angle of the diamond core is 83.89(3)°
and trans to this, the angle is 85.83(6)°. The other two
angles around the platinum center are 94.71(3)° and
95.66(6)°. The bridging Pt–Se–Pt angles are both almost
exactly 96°. From this data, it seems as though the visibly
twisted biphenyl-based diselenium ligand is not responsible
for the distortion of the geometry around the metal center
in 3, since the SePh ligands in 5 end up giving the complex
an extremely similar set of bond lengths and angles without
the ligand imposing a geometric restriction.
Table 4. Selected interatomic distances [Å] and angles [°] for com-
plex 3.
Pt(1)–P(1)
Pt(1)–Se(2)
Pt(1)–Se(31)
Pt(1)–Se(1)
2.202(2)
Pt(31)–P(31)
2.200(2)
2.4370(10) Pt(31)–Se(32)
2.4582(10) Pt(31)–Se(31)
2.4569(10) Pt(31)–Se(1)
2.4449(11)
2.4544(10)
2.4628(10)
Se(1)–C(19)
Se(31)–C(49)
Se(32)–C(56)
Se(2)–C(26)
1.928(9)
1.944(10)
1.960(9)
1.922(10)
P(1)–Pt(1)–Se(2)
P(1)–Pt(1)–Se(31)
Se(2)–Pt(1)–Se(1)
Se(31)–Pt(1)–Se(1) 83.89(3)
Se(2)–Pt(1)–Se(31) 173.11(4) Se(32)–Pt(31)–Se(1) 172.28(4)
P(1)–Pt(1)–Se(1) 177.60(7) P(31)–Pt(31)–Se(31) 177.84(7)
88.50(7)
93.86(7)
93.64(3)
P(31)–Pt(31)–Se(32) 88.72(7)
P(31)–Pt(31)–Se(1) 94.00(7)
Se(32)–Pt(31)–Se(31) 93.44(4)
Se(31)–Pt(31)–Se(1) 83.85(3)
C(19)–Se(1)–Pt(1) 93.9(3)
C(19)–Se(1)–Pt(31) 106.5(3)
Pt(1)–Se(1)–Pt(31) 96.04(3)
C(49)–Se(31)–Pt(31) 93.2(3)
C(49)–Se(31)–Pt(1) 107.1(3)
Pt(31)–Se(31)–Pt(1) 96.22(3)
Experimental Section
General: All synthetic procedures were performed under nitrogen
using standard Schlenk techniques unless otherwise stated, reagents
were obtained from commercial sources and used as received. Dry
C(26)–Se(2)–Pt(1) 110.1(3)
C(56)–Se(32)–Pt(31) 110.6(3)
solvents were collected from an MBraun solvent system. H, 13C,
1
31P, and 77Se spectra were recorded on a Jeol DELTA GSX270
spectrometer. 195Pt spectra were obtained on a Bruker AVII400.
Chemical shifts are reported in ppm and coupling constants (J) are
given in Hz. IR (KBr pellet) and Raman spectra (powder sample)
were obtained on a Perkin–Elmer system 2000 Fourier Transform
spectrometer. Elemental analysis was performed by the University
of St. Andrews, School of Chemistry Service. Positive-ion FAB
mass spectra were performed by the EPSRC National Mass Spec-
trometry Service, Swansea. Precious metals were provided by Cei-
mig Ltd.
Table 5. Selected interatomic distances [Å] and angles [°] for 5.
Pt(1)–P(1)
2.186(2)
Pt(31)–P(31)
2.193(2)
Pt(1)–Se(2)
Pt(1)–Se(1A)
Pt(1)–Se(1)
Se(1)–Pt(1A)
2.4493(9) Pt(31)–Se(32)
2.4697(9) Pt(31)–Se(3A)
2.4771(8) Pt(31)–Se(31)
2.4697(9) Se(31)–Pt(3A)
2.4445(8)
2.4632(8)
2.4763(8)
2.4632(8)
Se(1)–C(19)
Se(2)–C(25)
1.927(7)
1.932(8)
Se(31)–C(49)
Se(32)–C(55)
1.931(7)
1.925(8)
P(1)–Pt(1)–Se(2)
P(1)–Pt(1)–Se(1A)
Se(2)–Pt(1)–Se(1)
Se(1A)–Pt(1)–Se(1) 83.89(3)
Se(2)–Pt(1)–Se(1A) 175.74(3) Se(32)–Pt(31)–Se(3A) 176.46(3)
85.83(6)
95.66(6)
94.71(3)
P(31)–Pt(31)–Se(32)
84.01(5)
Synthetic Remarks: The compound cis-[Pt{P(OPh)3}2Cl2] was pre-
pared by adding two equivalents of P(OPh)3 to cis-[PtCl2(cod)] (cod
= 1,5-cyclooctadiene) in dichloromethane at room temperature in-
stead of by the procedure reported by Sabounchei et al.[20]
P(31)–Pt(31)–Se(3A) 96.90(5)
Se(3A)–Pt(31)–Se(31) 84.07(3)
Se(32)–Pt(31)–Se(31) 94.99(3)
P(1)–Pt(1)–Se(1)
178.57(5) P(31)–Pt(31)–Se(31)
178.86(6)
Synthesis of Naphtho[1,8-c,d][1,2]diselenole (Se2naph): Crystalline
naphthalene (6.10 g, 47.6 mmol) was added to a 500 mL round bot-
tom Schlenk flask. The flask was evacuated and purged with nitro-
gen. Butyllithium (BuLi) (46.8 mL of 2.5  in THF, 117 mmol) was
added dropwise via syringe with stirring, followed by the slow ad-
dition of TMEDA (17.7 mL, 117 mmol). Upon addition, the flask
became slightly warm and a white precipitate (pcc) formed. The
pcc dissolved as the solution yellowed and then became increas-
ingly darker until it was dark reddish in color. A reflux condenser
was added to the flask, which was then warmed to ca. 70 °C for
C(19)–Se(1)–Pt(1A) 98.9(2)
C(19)–Se(1)–Pt(1) 104.2(2)
Pt(1A)–Se(1)–Pt(1) 96.11(3)
C(49)–Se(31)–Pt(3A) 100.5(2)
C(49)–Se(31)–Pt(31) 103.7(2)
Pt(3A)–Se(31)–Pt(31) 95.93(3)
C(25)–Se(2)–Pt(1)
106.6(2)
C(55)–Se(32)–Pt(31) 106.3(2)
Rather unsurprisingly, given their similar coordination
spheres, the bond lengths in 3 and 5 are very similar
throughout the complexes (Table 4, Table 5). The Pt–P two hours. The mixture was allowed to cool to room temperature,
4040 Eur. J. Inorg. Chem. 2010, 4034–4043
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Platinum Complexes of Aromatic Selenolates
at which time the reflux condenser was replaced by a septum. The
mixture was then cooled to –70 °C using a dry ice/acetone bath.
Tetrahydrofuran (THF) (ca. 150 mL) was added dropwise via sy-
ringe. Selenium powder (11.1 g, 141 mmol) was then added at once.
The reaction mixture was allowed to slowly warm to room tem-
perature and was stirred overnight under nitrogen.
1186 (w), 1147 (s), 1116 (vs), 996 (vs), 913 (s), 881 (s), 860 (w), 820
(s), 799 (s), 741 (s), 663 (w), 558 (w), 509 (w), 485 (w), 468 (w), 381
1
(w) cm–1. HNMR (CDCl3): δ = 7.77–7.64 (m, 2 H, 3,5-H), 7.53–
7.40 (m, 1 H, 6-H), 1.52 [s, 9 H, -C(CH3)3] ppm. 13C NMR
(CDCl3): δ = 134.5 (s), 133.6 (s), 132.9 (s), 131.4 (s), 131.2 (s), 130.6
(s), 130.2 (s), 130.1 (s), 124.9 (s), 124.1 (s), 29.8 (s), 28.7 (s) ppm.
77SeNMR (CDCl3): δ = 454, 374 ppm. MS (TOF MS EI+): m/z
(%) =497.98 (100) [M+].
Caution! As the mixture warms to room temperature, the flask be-
comes slightly pressurized. Make sure the stopper is clipped and
the flask is opened to nitrogen.
Synthesis for [Pt(L){P(OPh)3}2], L = Se2naph (1) and mt-Se2naph
(2): In a Schlenk tube, ca. 10 mL of dry THF was added to 1 mol-
equiv. of L, the resulting purple solution was stirred for 10 min and
then, 2 mol-equiv. of a 1  solution of LiBEt3H in THF was added
dropwise via syringe. Upon addition, the purple solution turned
bright yellow and gas evolution was observed. This solution was
stirred ca. 15 min and [Pt{P(OPh)3}2Cl2] was added. The solution
turned orange in color and was stirred 12 h, after which ca. 1 g of
silica gel was added and the solvent was evaporated under vacuum.
The flask containing the orange solid was opened to the air and
the solid was placed on top of a short hexane-packed silica gel
column. The column was eluted with hexane to remove any unre-
acted starting material and then washed with CH2Cl2. The CH2Cl2
band was collected and the solvent was removed under vacuum.
Orange crystals were obtained for 1 (97 mg, 53%) and 2 (109 mg,
50%) after recrystallization from CH2Cl2 by pentane diffusion.
The next day, the flask was opened and the mixture was poured
into a 2 separating funnel where ca. 500 mL of distilled water and
ca. 300 mL of hexane was then added. It was difficult to see the
separation line, but as the water layer was removed the line became
more evident. The hexane layer, a clear purple solution, was col-
lected. Silica gel was added to the organic layer and the solvent
was evaporated. The silica gel/product was placed on top of a silica
column and the product was eluted with hexane. The purple band
was collected and the solvent evaporated. The purple solid was dis-
solved in a minimal amount of dichloromethane. The solution was
then layered with hexane and placed in the freezer for recrystalli-
zation; yield 3.544 g, 26%. 1H and 77Se NMR matched those of
the previous reported samples.[1]
Synthesis of 2,7-Di-tert-butylnaphtho[1,8-c,d][1,2]diselenole (dt-
Se2naph) and 2-tert-butylnaphtho[1,8-c,d][1,2]diselenole (mt-
[Pt(Se2naph){P(OPh)3}2] (1): Se2naph (47 mg, 165 mmol), 0.33 mL
of 1  soln of LiBEt3H in THF, and [Pt{P(OPh)3}2Cl2] (147 mg,
165 mmol). C46H36O6P2PtSe2·CH2Cl2: calcd. C 47.60, H 3.23;
found C 47.79, H 3.10. FAB+ MS: m/z = 1100 [M+]. IR (KBr):
Se2naph):
2,7-Di-tert-butylnaphtho[1,8-c,d][1,2]diselenole (dt-
Se2naph) and 2-tert-butylnaphtho[1,8-c,d][1,2]diselenole (mt-
Se2naph) were prepared by methods reported for the thiol ana-
logues.[15,16] Se2naph (0.38 g, 1.3 mmol), tert-butyl chloride
(0.43 mL, 3.9 mmol), and CH3NO2 (ca. 7 mL), were added to a
100 mL round bottom Schlenk flask. The reaction was heated with
stirring to about 80 °C and AlCl3 (36 mg, 0.27 mmol) was added.
The mixture continued to heat at about 80 °C for one hour. After
the reaction cooled to room temperature, distilled water was added,
which then was extracted with dichloromethane. The organic layer
was removed, dried with MgSO4, filtered, and the solvent was evap-
orated. These compounds were purified by column chromatog-
raphy on silica gel elution using hexane, with mt-Se2naph eluting
first, then dt-Se2naph, followed by starting material. dt-Se2naph
was crystallized by slow evaporation of a pentane solution to give
orange blocks (17 mg, 3%). mt-Se2naph is a dark red oil (104 mg,
23%), and finally 81 mg (21%) of the starting material was reco-
vered.
ν
= 1587, 1486, 1182, 1159, 918, 778, 757, 687, 596, 496 cm–1.
˜
max
Raman: ν = 30720, 1591, 1538, 1333, 1007, 851, 733, 530, 200 cm–1.
˜
All NMR samples were prepared from crystalline samples in
1
CDCl3. H NMR: δ = 7.6 (d, JH,H = 7 Hz), 7.5 (d, JH,H = 7 Hz),
7.2–6.9 (m), 6.9 (t, JH,H = 7 Hz) ppm. 13C NMR: δ = 150.9, 136.3,
135.1, 129.8, 126.9, 125.2, 124.7, 120.9 ppm. 31P NMR: δ = 87 ppm
(JP,Pt = 4711 Hz) (JP-Se = 28 Hz). 77Se NMR: δ = 140 ppm (t,
JSe-P = 28 Hz) (JSe-Pt = 205 Hz). 195Pt NMR: δ = –4711 ppm (t,
JPt,P = 4711 Hz) (JPt-Se = 205 Hz).
[Pt(mt-Se2naph){P(OPh)3}2] (2): mt-Se2naph (64 mg, 187 mmol),
0.37 mL of 1  soln of LiBEt3H in THF, and [Pt{P(OPh)3}2Cl2]
(166 mg, 187 mmol). C50H44O6P2PtSe2·0.5CH2Cl2:: calcd. C 50.50,
H 3.78; found C 50.51, H 3.49. FAB+ MS: m/z = 1156 [M+]. IR
(KBr): ν
= 1588, 1488, 1186, 1160, 922, 776, 756, 686, 595, 497
˜
˜
max
cm–1. Raman: ν = 3066, 1595, 1586, 1515, 1340, 1007, 857, 733, 185
1
mt-Se2naph: H NMR (CDCl3): δ = 7.52–7.17 (m, 5 H), 1.53 (s, 9
cm–1. All NMR samples were prepared from crystalline samples in
CDCl3. 1H NMR: δ = 7.4–7.0 (m), 6.9 (t, JH,H = 7 Hz)., 1.7 (s)
ppm. 13C NMR: δ = 151.0, 150.9, 147.0, 142.5, 132.9, 132.1, 131.9,
129.7, 129.6, 126.5, 125.5, 125.2, 125.0, 123.9, 123.2, 121.0, 120.9,
H) ppm. 77Se NMR (CDCl3): δ = 414 (s), 414 (d, JSe-Se = 345 Hz),
360 (s), 360 (d, JSe-Se = 345 Hz) ppm. 13C NMR (CDCl3): δ =
144.3, 139.5, 138.8, 138.3, 136.5, 126.8, 125.8, 124.8, 123.3, 122.0,
36.5, 29.2 ppm. MS (TOF MS CI):m/z = 339 [78Se, 80Se], 341 [80Se].
120.7, 120.6, 38.2, 31.6 ppm. 31P NMR: δ = 89 ppm (d, JP-P
=
1
dt-Se2naph: HNMR (CDCl3): δ = 7.52–7.44 (m, JH,H = 8, 21 Hz,
68 Hz), (JP,Pt = 4686 Hz) (JP-Se = 19, 28) 86 ppm (d, JP P = 68 Hz),
(JP,Pt = 4669 Hz) (JP Se = 35). 77Se NMR: δ = 258 ppm (dd, JSe-P
= 19, 35 Hz) (JSe-Pt = 329 Hz), 138 ppm (dd, JSe-P = 7, 28 Hz)
(JSe-Pt = 212 Hz). 195Pt NMR: δ = –4575 ppm (observed is apparent
triplet JPt,P ≈ 4680 Hz).
4 H), 1.56 (s, 18 H) ppm. 77SeNMR (CDCl3): δ = 353 (s) ppm.
13CNMR (CDCl3): δ = 144.05, 140.37, 136.99, 134.98, 125.82,
124.37, 36.66, 29.10 ppm. MS (TOF MS CI): m/z = 396 [78Se, 80Se],
398 [80Se].
Synthesis of 4,7-Dibromo-2-tert-butylnaphtho[1,8-c,d][1,2]diselenole
(Se2naphBr2): A solution of 2-tert-butylnaphtho[1,8-c,d][1,2]di-
selenole (mt-Se2naph) (0.11 g, 0.33 mmol) in dichloromethane
(10 mL) was cooled to 0 °C and slowly treated with bromine
(0.11 g, 0.034 mL, 0.66 mmol). An analytically pure sample was ob-
tained by crystallisation from diffusion of pentane into a dichloro-
Synthesis of [Pt2(dibenzSe2)2{P(OPh)3}2] (3): In a Schlenk tube,
ca. 10 mL of dry THF was added to 1 mol-equiv. of dibenzSe2, the
resulting pale orange solution was stirred for 10 min and then
2 mol-equiv. of a 1  solution of LiBEt3H in THF was added drop-
wise via syringe. Upon addition, the solution turned very pale yel-
low, then clear with gas evolution. This solution was stirred
ca. 15 min and [Pt{P(OPh)3}2Cl2] was added. The solution turned
methane solution of the product (0.1 g, 74%). IR (KBr tablet): ν
˜
max
= 3424 (br. s), 3069 (w), 2955 (s), 2854 (w), 1584 (w), 1568 (w), bright yellow in color and was stirred 12 h, after which time ca. 1 g
1514 (w), 1482 (s), 1466 (vs), 1392 (s), 1361 (s), 1282 (s), 1218 (s), of silica gel was added and the solvent was evaporated under vac-
Eur. J. Inorg. Chem. 2010, 4034–4043
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4041

A. L. Fuller, F. R. Knight, A. M. Z. Slawin, J. D. Woollins
FULL PAPER
uum. The flask containing the yellow solid was opened to the air
and the solid was placed on top of a short hexane-packed silica gel
column. The column was eluted with hexane to remove any unre-
ca. 15 min and [Pt{P(OPh)3}2Cl2] was added. The solution turned
bright orange in color and was stirred 12 h, after which time ca. 1 g
of silica gel was added and the solvent was evaporated. The flask
acted starting material and then washed with 2:1 CH2Cl2/hexane. containing the orange solid was opened to the air and the solid
The resulting bright yellow band was collected and the solvent was
removed under vacuum. X-ray quality crystals were obtained for 3
after recrystallization from CH2Cl2 by pentane diffusion. FAB+
MS: m/z 1631 [M+] (matches theoretical isotope profile for 3). IR
was placed on a small hexane silica gel column. The column was
eluted with hexane to remove any unreacted starting material and
then washed with 2:1 CH2Cl2/hexane. This orange band was col-
lected and the solvent was removed under vacuum. Complexes 4
and 5 co-crystallized out of the same CH2Cl2 solution by pentane
(KBr): νmax = 1588, 1486, 1184, 1160, 1025, 922, 765, 687, 595, 491
˜
cm–1. Raman IR: ν = 3066, 1589, 1030, 1008 cm–1. NMR samples diffusion. Complex 4 is deep orange in color, almost red, whereas
˜
were prepared from crystalline samples in CDCl3. 31P NMR: δ =
85 ppm (JP,Pt = 4685 Hz) (JP-Se = 21). 77Se NMR: δ = 225 ppm (t,
5 is bright yellow. All data was obtained from crystalline solid that
contained both 4 and 5. C48H40O6P2PtSe2 (4) (1127.80): calcd. C
JP-Se = 21) (JPt-Se = 183 Hz). 195Pt NMR: δ = –4570 ppm (t, JPt,P 51.12, H 3.57 and for C60H50O6P2Pt2Se4 (5) (1635.02): calcd. C
= 4685 Hz) (JPt-Se = 183 Hz). The NMR spectroscopic data seem
to suggest that the predominant species in solution is
[Pt(dibenzSe2){P(OPh)3}2].
44.08, H 3.08; found C 44.62, H 2.81. FAB+ MS: m/z 1635 [M+]
(matches theoretical isotope profile for 5, but there are higher mo-
lecular ion peaks in the sample). IR (KBr): ν
= 1587, 1485,
˜
max
1183, 1156, 919, 784, 686, 601, 488 cm–1. Raman IR: ν = 3063,
˜
Synthesis of cis-[Pt(SePh)2{P(OPh)3}2] (4) and [Pt2(SePh)4{P-
(OPh)3}2] (5): In a Schlenk tube, ca. 10 mL of dry THF was added
to 1 mol-equiv. of Se2Ph2, the resulting yellow solution was stirred
for 10 min and then 2 mol-equiv. of a 1  solution of LiBEt3H in
THF was added dropwise via syringe. Upon addition, the solution
turned pale yellow with gas evolution. This solution was stirred
1597, 1576, 1220, 1169, 1071, 1001, 226, 178 cm–1. NMR samples
were prepared in CDCl3. 31P NMR: δ = 84 ppm. (JP,Pt = 4724 Hz)
(JP-Se = 28 Hz). 77Se NMR: δ = 222 ppm (t, JP-Se = 28 Hz) (JSe-Pt
= 188 Hz). 195Pt NMR: δ = –4075 ppm (t, JPt,P = 4729 Hz). NMR
spectroscopic data seem to suggest that the mononuclear species 4
exists in solution, rather than the dinuclear species 5.
Table 6. Crystallographic data for compounds dt-Se2naph, mt-Se2naphBr2 and 1–5.
dt-Se2naph
mt-Se2naphBr2
1
2
3
4
5
Empirical formula C18H22Se2
C14H14Br2Se2
499.99
–148(1)
C46H36O6Se2P2Pt PtC51H46O6P2Se2Cl2 C62H50Cl4O6P2Pt2Se4 C146H124O18P6Pt3Se6Cl4 C60H50O6P2Pt2Se4
Formula weight
Temperature [°C]
Crystal colour,
habit
396.29
–148(1)
1099.74
–148(1)
1240.78
–148(1)
1800.78
–180(1)
3553.26
–148(1)
1634.96
–180(1)
orange, block
red, prism
orange, block
yellow, platelet
yellow, prism
orange, block
yellow, prism
Crystal dimensions
[mm3]
0.55ϫ0.40ϫ0.30 0.09ϫ0.06ϫ0.06 0.22ϫ0.15ϫ0.07 0.41ϫ0.14ϫ0.10
orthorhombic monoclinic orthorhombic monoclinic
0.20ϫ0.20ϫ0.20
monoclinic
0.52ϫ0.10ϫ0.06
monoclinic
0.10ϫ0.03ϫ0.03
triclinic
Crystal system
Lattice parameters a = 11.333(11) Å a = 9.638(7) Å
b = 12.079(11) Å b = 7.112(5) Å
a = 13.3431(5) Å a = 17.1347(5) Å
b = 13.5580(5) Å b = 26.5360(8) Å
a = 12.0039(15) Å
b = 20.430(2) Å
c = 25.009(3) Å
–
β = 99.836(3)°
–
6043.1(13)
Cc
4
a = 61.179(3) Å
b = 11.9162(4) Å
c = 18.9059(9) Å
–
β = 98.6466(18)°
–
13626.1(11)
C2/c
4
1.732
6960
48.776
a = 10.1847(12) Å
b = 13.7001(16) Å
c = 20.338(2) Å
α = 83.840(7)°
β = 82.868(7)°
γ = 85.896(8)°
2794.7(6)
P1
2
1.943
1560
77.13
c = 12.029(11) Å c = 10.499(8) Å c = 22.8535(8) Å c = 11.0032(3) Å
–
–
–
–
β = 90°
–
β = 94.263(15)° β = 90°
–
β = 102.4922(8)°
–
–
Volume [Å3]
Space group
Z value
1647(3)
Pcca
4
1.598
792
717.6(8)
P21/m
2
2.314
472
4134.3(3)
P212121
4
4884.6(2)
Cc
4
¯
Dcalcd. [g/cm3]
F(000)
1.767
2144
52.68
1.687
2440
45.75
1.979
3440
73.15
m(MoKa) [cm–1]
Number of reflec-
tions measured
Rint
44.807
107.166
13383
0.032
4132
0.039
43187
0.095
25442
0.041
19245
0.0453
52775
0.329
18111
0.047
Min.–max. trans-
missions
Independent reflec-
tions
0.130–0.261
1508
0.373–0.526
1362
0.398–0.692
9468
0.304–0.633
11089
0.7102–1.0000
8754
0.383–0.746
11981
0.6118–1.0000
9897
Observed reflection
(no. variables)
Reflection/param-
eter ratio
1314 (94)
16.04
1267 (115)
11.84
8094 (515)
18.38
9956 (578)
19.19
7937 (722)
12.12
7175 (826)
14.5
7534 (688)
14.39
Residuals: R1
[I Ͼ 2.00s(I)]
Residuals: R (all
reflections)
Residuals: wR2 (all
reflections)
0.0385
0.0452
0.048
0.0345
0.0362
0.125
0.0453
0.0444
0.0499
0.0629
0.061
0.042
0.0414
0.1953
0.067
0.1011
0.1072
0.0543
0.0705
0.3989
0.0726
Goodness-of-fit
indicator
Flack parameter
Max. peak in final
diff. map [e/Å3]
Min. peak in final
diff. map [e/Å3]
1.093
–
1.181
–
1.051
–0.006(5)
0.987
0.001(3)
0.874
–0.005(7)
1.145
–
0.975
–
0.83
0.66
2.59
1.54
1.744
6.56
1.807
–0.55
–0.99
–1.02
–0.70
–1.424
–10.18
–1.542
4042
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 4034–4043

Platinum Complexes of Aromatic Selenolates
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X-ray Crystallography: Crystal structure data for 1, 2, dt-Se2naph
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Rigaku Saturn CCD diffractometer using Mo-Kα radiation (graph-
ite monochromator optic, λ = 0.71073 Å), 4 was determined by
using a Rigaku SCX-Mini whilst 3 and 5 were determined by using
a Rigaku MM007 rotating anode and Mercury CCD. All data were
corrected for absorption. The structure was solved by direct meth-
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of all data. Refinements were performed using SHELXTL (version
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(for 4), -759121 (for 5), -759122 (for dt-Se2naph), -759123 (for mt-
Se2naphBr2) contain the supplementary crystallographic data for
this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
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Received: March 31, 2010
Published Online: July 9, 2010
Eur. J. Inorg. Chem. 2010, 4034–4043
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4043