Oxidation reactions of 1,8-bis(phosphino)naphthalenes: Syntheses and molecular structures of bis(phosphine oxides) and of a bis(phosphine sulfide)

Article abstract of DOI:10.1002/hc.7

A series of naphthalenediyl-1,8-bis(phosphine oxides) 1-RR′P(:O)(C₁₀H₆)-8-P(:O)RR′ (R = R′ = Me (2a), Et (2b), iPr (2c), Cy (2d), Ph (2f) and R = tBu, R′ = Ph (2e) was prepared by oxidation of the corresponding bis(phosphines) 1a-f w

Full text of DOI:10.1002/hc.7

Heteroatom Chemistry
Volume 12, Number 2, 2001
Oxidation Reactions of 1,8-
Bis(phosphino)naphthalenes: Syntheses and
Molecular Structures of Bis(phosphine oxides)
and of a Bis(phosphine sulfide)
Atilla Karac¸ar, Matthias Freytag, Holger Tho¨nnessen,
Jan Omelanczuk,* Peter G. Jones, Rainer Bartsch,
and Reinhard Schmutzler
Institut fu¨ r Anorganische und Analytische Chemie der Technischen Universita¨t, Postfach 3329,
D-38023 Braunschweig, Germany
Received 18 August 2000; revised 22 September 2000
bis(phosphines). In each case, the proximity of the
ABSTRACT:
A
series of naphthalenediyl-1,8-
P(:X)R2 groups (X ס O, S) led to distortion, the main
feature of which was the out-of-plane displacement of
the P atoms. ᭧ 2001 John Wiley & Sons, Inc. Hetero-
atom Chem 12:102–113, 2001
bis(phosphine oxides) 1-RRЈP(:O)(C10H6)-8-P(:O)RRЈ
(R ס RЈ ס Me (2a), Et (2b), iPr (2c), Cy (2d), Ph (2f)
and R ס tBu, RЈ ס Ph (2e) was prepared by oxidation
of the corresponding bis(phosphines) 1a–f with mo-
lecular oxygen or H2O2 •(H2N)2C(:O) and characterized
by NMR and IR spectroscopy, mass spectrometry, and
elemental analysis (2a, 2b, 2d–f). X-ray crystal struc-
ture analyses were performed for 1,8-bis(dimeth-
ylphosphinyl)naphthalene (2a), (RR,SS)-1,8-bis-
(phenyl-tert-butylphosphinyl)naphthalene (2e) and
1,8-bis(diphenylphosphinyl)naphthalene (2f). Treat-
ment of 1,8-bis(diphenylphosphino)naphthalene
(dppn, 1f) with an excess of sulfur in hot toluene
afforded the bis(phosphine sulfide) 1-Ph2P(:S)
(C10H6)-8-P(:S)Ph2 (dppnS2, 3f) the structure of which
was elucidated by X-ray crystal structure analysis. The
geometries of the compounds 2a, 2e, 2f, and 3f re-
vealed an increase of strain from the corresponding
INTRODUCTION
Steric strain associated with 1,8-disubstituted naph-
thalenes (peri-substitution) has received much atten-
tion [1,2]. Relief of such strain may be accomplished
by in- and out-of-plane deflection of the substituents
and distortion or buckling of the aromatic frame-
work. Moreover, the close proximity of NMR-active
nuclei endows these compounds with unique NMR-
spectroscopic properties [3].
Recently, we described the molecular structures
of some 1,8-bis(dialkylphosphino)naphthalenes(1a–
d), a 1,8-bis(alkylarylphosphino)naphthalene (1e)
and
a 1,8-bis[(dialkylamino)phosphino]naphthal-
Dedicated to Professor Richard Neidlein on the occasion of his
70th birthday.
*On leave from Center of Molecular and Macromolecular Stud-
ies, Polish Academy of Sciences, 90-363 Lodz, Sienkiewicza 112,
Poland.
Correspondence to: Reinhard Schmutzler.
Contract Grant Sponsor: Fonds der Chemischen Industrie.
᭧ 2001 John Wiley & Sons, Inc.
ene (1g) [4] (Scheme 1). These compounds can be
regarded as phosphorus analogues of 1,8-bis(di-
methylamino)naphthalene, known as proton sponge
[5]. There is considerable interest in bis(phosphines)
with a rigid C3-backbone as bidentate ligands in tran-
sition metal–catalyzed reactions, because their pal-
102

Oxidation Reactions of 1,8-Bis(phosphino)naphthalenes 103
SCHEME 1 1,8-Bis(phosphino)naphthalenes.
SCHEME
2 Quaternization of 1,8-bis(dimethylphos-
phino)naphthalene 1a [3a].
ladium(II) chelates turned out to be active catalysts
for CO/ethylene copolymerization [6]. The ligand
1,8-bis(diphenylphosphino)naphthalene (dppn, 1f),
in particular, was reported to have high catalytic ac-
tivity in the cyanation of vinylic halides and in the
alkylation of heteroarenes [7].
Quaternization of the trivalent phosphorus at-
oms, for example, by oxidation, should drastically
increase the steric strain in 1,8-bis(phosphino)
naphthalenes. However, Schmidbaur and Costa [3a]
found that two-fold quaternization of 1,8-bis-
(dimethylphosphino)naphthalene (1a) by alkylation
with methyl iodide failed because of the unfavorable
steric and electronic situation in the expected dica-
tion 1aЉ (Scheme 2).
SCHEME 3 Oxidation of 1a–f with air or H2O2 •(H2N)2C(:O).
As part of our interest in 1,8-bis(phosphino)-
naphthalene ligands, we have also studied their be-
havior toward oxygen, sulfur, selenium and tellu-
rium. The resulting phosphine chalcogenides are
useful model compounds for the resolution of race-
mic, pro-chiral phosphines, such as 1e, with chirality
at phosphorus [8], and may be used for the com-
plexation of coinage metals [9] and in metal extrac-
tion [10].
2b, 2d–f are colorless solids, which are readily sol-
uble in chlorinated solvents (CHCl3, CH2Cl2) but
poorly soluble in ethers (THF, Et2O) and in alcohols
(MeOH, EtOH).
Treatment of 1f with two equivalents of sulfur in
toluene at ם80ꢀC selectively afforded the bis-
(phosphine sulfide) 3f (dppnS2). The reaction pro-
ceeded via the phosphine sulfide 3fЈ, which was com-
pletely transformed to 3f in the presence of sulfur
(Scheme 4a). Compound 3f was isolated as a yellow,
air-stable solid, which is soluble in all common non-
polar organic solvents.
RESULTS AND DISCUSSION
Oxidation Reactions of 1,8-
Bis(phosphino)naphthalenes
The reaction of 1f with two equivalents of grey
selenium powder, carried out under standard con-
ditions [11], did not afford the bis(phosphine selen-
ide) 4f. Instead, only the phosphine selenide 4fЈ
(dppnSe) was obtained (Scheme 4b). Even after pro-
longed heating of 4fЈ with excess selenium in tolu-
ene, formation of 4f could not be observed. Similarly,
treatment of 1f with elemental tellurium in boiling
toluene afforded neither the bis(phosphine telluride)
5f nor the phosphine telluride 5fЈ (Scheme 4c). We
ascribe this behavior to the bulk of the seleno- and
the tellurophosphinyl groups and to the inherent in-
stability of the latter [12]. All isolated new com-
pounds were characterized by a combination of 1H,
13C, and 31P{1H} (2c) NMR spectroscopy, IR spectros-
copy, electron impact–mass spectrometry (EI-MS),
In contrast to previous reports [3a,3c,7], in which
1,8-bis(dimethylphosphino)naphthalene (1a) and
1,8-bis(diphenylphosphino)naphthalene (1f) were
described as air-stable solids, we found that, apart
from the bulky 1,8-bis(phenyl-tert-butylphos-
phino)naphthalene (1e), 1,8-bis(diorganophos-
phino)naphthalenes 1a–d and 1f were air sensitive,
even in the solid state. We ascribed this behavior to
a mutual enhancement of basicity of the phosphino
groups caused by their spatial proximity [4a].
The bis(phosphine oxides) 2a–d and 2f were thus
prepared by exposing the corresponding bis(phos-
phines) 1a–d and 1f to air, while 2e was obtained by
oxidation of 1e with H2O2 •(H2N)2C(:O) in dichloro-
methane (Scheme 3). The bis(phosphine oxides) 2a,

104 Karac¸ar et al.
P-2 because of their symmetrical orientation, triplets
were observed at dC ꢁ 133–136 (C-4a) and dC ꢁ 131–
134 (C-8a) with typical values of 3JCP ꢁ 8–10 Hz and
2JCP ꢁ 4–8 Hz. For C-1 and C-8 doublets of doublets
with 1JCP ꢁ 95–108 Hz and 3JCP ꢁ 2–3 Hz due to cou-
pling to P-1 and P-2 were observed between dC ꢁ 121
3
and dC ꢁ 133. In the 13C NMR spectrum of 2d, JCP
was unresolved. Interestingly, a doublet of doublets
with a small coupling of 4JCP ס 1.3 Hz was observed
for C-2,7 in the spectrum of 2b.
In the spectra of the parent phosphines 1a–f, the
carbon atoms C-␣, C-b, and C-c, as well as C-i in 1e
showed some interesting NMR-spectroscopic fea-
tures. For C-␣ in 1a and 1e, C-b and C-bЈ in 1b–e,
C-c and C-cЈ in 1d, and C-i in 1e, virtual triplets were
observed. This was interpreted as direct coupling
through space that resulted from a considerable P-P
interaction via the nonbonding electron pairs at P-1
and P-2 [3a,4a]. In the bis(phosphine oxides), no
nonbonding electron pairs were available for
through space interactions. Thus, for C-␣ in 2a, 2b,
and 2e; C-b in 2b; C-c in 2d; C-i, C-o, C-m, and C-p
in 2f and 3f; only doublets were observed that re-
sulted from direct coupling to the next phosphorus
nucleus. Surprisingly, the 13C NMR spectrum of 2e
SCHEME 4 Reaction of 1f with elemental sulfur, selenium,
and tellurium.
1
showed a doublet of doublets for C-i with JCP ꢁ 52
Hz and 5JCP ꢁ 3 Hz.
and elemental analysis. X-ray crystal structure de-
terminations were carried out for 2a, RR/SS-2e, 2f,
and 3f.
The phosphine chalcogenides 3fЈ and 4fЈ have
potential significance as hemilabile, mixed-donor li-
gands in coordination chemistry. Compound 3fЈ
could even play a role in homogeneous catalysis [13].
Their preparation and characterization together
with their coordination chemistry is described in an-
other article [14].
As was expected, the d(C-␣) values of the substit-
uents R and RЈ at phosphorus increased in the order
Me ꢂ Et ꢂ Cy ꢂ tBu/Ph (2a ꢂ 2b ꢂ 2d ꢂ 2e) (b-
effect) whereas J(CP) values decreased in the order
1JCP ꢃ 3JCP ꢃ 2JCP ꢃ 4JCP.
1
At room temperature, the 13C (and H) NMR
spectra of 2d and 3f displayed broad signals indica-
1
tive of dynamic behavior. In the H NMR spectrum
of 3f, the signal for o-H was broad and unresolved,
and therefore C-o could not be observed in the CH
HMQC and CH HMBC experiments. We suggest that
in dppnS2 (3f) rotation of the phenyl groups about
the P-C(phenyl) bond is hindered compared to ro-
tation of the phenyl groups in the less bulky dppnO2
(2f).
13C NMR Spectra
The 13C NMR data of compounds 2a, 2b, 2d–f, and
3f are summarized in Table 1. The atom numbering
(C, H, P) is explained in Scheme 5. The assignment
of the signals and the evaluation of the coupling con-
stants are based on 2D experiments (HH, CH corre-
lation spectroscopy [COSY], correlation spectros-
copy in long-range coupling [COLOC] [2f], and CH
H-detected heteronuclear multiple quantum, coher-
ence via direct coupling [HMQC]/heteronuclear
multiple bond connectivity by 2D multiple quantum
NMR [HMBC] [2e,3f]) or on a comparison of the
NMR data of 2a, 2b, and 2d with those of 2e.
1H NMR Spectra
1
The H NMR spectra of 2a and 2b showed the ex-
pected ABC signal pattern for the aromatic protons
of the 1,8-naphthalenediyl units with typical J-values
(without 31P: [AAЈBBЈCCЈ] spin systems). Due to the
presence of naphthalenediyl and phenyl groups, the
aromatic region in the 1H NMR spectra of 2e, 2f, and
3f was complex.
The quaternary carbon atoms C-4a, C-8a, and
C-1,8 of the naphthalenediyl unit gave rise to char-
acteristic signals. For C-4a and C-8a, which experi-
ence coupling to both phosphorus nuclei P-1 and
1
In the H NMR spectra of the phosphines 1a–e
the aliphatic region was complicated by (a) coupling
of protons with P-1 and P-2 (X and XЈ), and (b) dias-

Oxidation Reactions of 1,8-Bis(phosphino)naphthalenes 105
TABLE 1 31P{1H} and 13C NMRa Data of 1,8-Naphthalenediyl-bis(phosphine oxides) 2a, 2b, 2d–f and of the Bis(phosphine
sulfide) 3f [in CDCl3, rel. H3PO4 (ext. ס 0) and CDCl3 (int. ס 77.05): d, JPC in Hz and multiplicity in (O)]
Compound (dbP)
C-1,8
C-2,7
C-3,6
C-4,5
C-4a
C-8a
C-i
C-o
C-m
C-p
C-␣
C-b
2a
132.70
102.4, 2.5
(dd)
131.72 124.54 131.96 134.06 131.18
—
—
—
—
21.17
73.8
(d)
—
12.8
(d)
15.8
(d)
2.9
(d)
8.8
(t)
5.3
(t)
(39.9)
2b
131.18
131.80 124.41 131.60 133.80 133.18
—
—
—
—
—
25.00 6.10
95.3, 2.3 12.0, 1.3 14.4 3.1, 1.3
8.3
(t)
4.2
(t)
70.3
(d)
5.5
(d)
—
(48.9)
(dd)
127.91
101
(dd)
(d)
(dd)
—
2dd
131.24 124.39
133.19 134.09
26.18
31.1
(d)
38.43 26.51
br
(m)
—
—
(br, m)
13.2
(d)
8
(t)
4
(t)
12.8
(d)
(46.3)
(d)
2e
130.74
98.2, 2.2
(dd)
129.96
107.7, 2.4
(dd)
134.24 124.09 132.35 133.76 133.70 130.72 131.53 127.58 131.02 36.99 25.63
—
(s)
13.9
(d)
—
(s)
8.1
(t)
covered 51.9, 2.9
(t) (dd)
8.5
(d)
11.5
(d)
—
(s)
72.2
(d)
—
—
(s)
—
(38.6)
2f
137.63 123.99 132.78 134.30 134.44 137.85 131.41 137.72 130.42
12.2
(d)
14.9
(d)
2.9
(d)
9.0
(t)
6.0
(t)
106.8
(d)
9.4
(d)
12.2
(d)
2.4
(d)
(31.5)
3f
121.40
97.5, 3.2
(vdd)
142.21 126.11 138.36 135.60 133.00 126.70 131.80 129.67 134.12
—
—
13.6
(d)
15.2
(d)
—
(s, br)
9.7
(t)
7.5
(t)
112.5
(d)
10.8
(d)
13.3
(d)
2.9
(d)
(46.2)
aRecorded at 50.3 MHz; assignments are based on CH COSY, COLOC (2f) and HC HMBC, HC HMQC (2e, 3f) determinations at 100.61 MHz
or on comparison (2a, 2b, 2d, with 2e).
b2c: dP ס 52.4.
c31P NMR: dP ס 48.9 [mc (ꢁ octet), JPH ꢁ 13 Hz].
dC-i, -o, -m, -p denote C-␣, -b, -c, -d, respectively.
coupled spectra, the virtual triplets were simplified
to singlets and the virtual quintet was reduced to a
virtual triplet. Similarly, in the bis(phosphine ox-
ides), doublets (2a, 2e) and a doublet of triplets (2b)
were observed for the methyl protons, formally cor-
responding to [A6X]–(2a), [A9X]–(2e) and [A6B4X]–
(2b) spin systems. This again illustrates how the nu-
clear magnetic through space interaction in the
bis(phosphines) was reduced by oxidation of the
phosphorus atoms. Our results support the expla-
nation of magnetic through space interactions in
1,8-bis(phosphino)naphthalenes by (1) a mutual
overlap of the nonbonding electron pairs on phos-
phorus or (2) an H-contact with the electron pair on
the neighboring P atom by rotation of the R2P group
about the P–C(naphthyl)-axis [3a].
The proton NMR spectrum of 2d showed very
SCHEME 5 The atom numbering (C, H, P) in 1,8-bis(phos-
complex, unresolved, broad multiplets between dH ס
phinyl)naphthalenes.
0.50 and dH ס 4.00 and at dH ס 7.65. Apparently, a
1
thorough H and 13C NMR spectroscopic investiga-
tion of 2d is complicated by line-broadening caused
by dynamic processes.
tereotopy of methylene and/or methyl protons in the
case of 1b–e [4a]. The spectra of the bis(phosphines)
thus displayed signals corresponding to spin systems
of the type [A6AЈXXЈ] (1a) [3a], [A6AЈB4BЈXXЈ] (1b),
6
6
4
31P{1H} NMR Spectra
[A2AЈ2B4BЈC4CЈD2DЈXXЈ] (1d) and [A9AЈXXЈ] (1e)
4
4
2
9
(diastereotopy of protons was not taken into ac-
count). Hence, for the methyl protons in 1a and 1e,
virtual triplets were observed, whereas the methyl
protons in 1b gave a virtual quintet. In the 31P-de-
The 31P{1H} NMR spectra of the bis(phosphine ox-
ides) 2a–f (recorded in CDCl3) showed sharp singlets.
The dP values (Table 1) were in a range typical of
phosphine oxides and sulfides [15] (cf. Ph3P(:O),

106 Karac¸ar et al.
dP ס 27.0 and Ph3P(:S), dP ס 42.6). The dP values of
2a–f were shifted to high energy in the order [R,RЈ]:
[Ph,Ph] (2f); [tBu,Ph] (2e); [Me,Me] (2a); [Cy, Cy]
(2d); [Et,Et] (2b); [iPr, iPr] (2c). For 2c and particu-
larly 2d, the signals were considerably broader than
those of the corresponding bis(phosphines), indicat-
ing hindered rotation about the P–C(naphthyl)
bonds.
X-Ray Crystal Structure Determinations
The molecular structures of 2a, (S,S)-2e, 2f, and 3f
are shown in Figures 1–3.
Whereas (S,S)-2e and 3f display crystallographic
two-fold symmetry, the structures of 2a and 2f dis-
play only approximate noncrystallographic C2-sym-
metry about the C9–C10 bond (Figure 3). Perhaps
surprisingly, the compounds 2f and 3f are not iso-
structural. The P(:O)RRЈ groups in 2a, (S,S)-2e, and
2f lie close to each other, with P•••P distances be-
tween 337.9 and 347.9 pm (Table 3), still well within
380 pm, the double van der Waals radius of phos-
phorus [16], and O•••O distances between 291.9 and
298.3 pm. In the bis(phosphine sulfide) 3f, the P•••P
[374.6 pm] and the S•••S [368.5 pm] distances are
considerably larger than the P•••P and the O•••O
distances in the bis(phosphine oxides) (see following
section). As in the phosphines 1a/1aЈ (1aЈ denotes a
second independent molecule), 1e, and 1f, the close
proximity of the two bulky peri-substituents leads to
in-plane and out-of-plane displacement of the P at-
oms, the latter being the main feature of the struc-
tures studied in this article. We were particularly in-
terested in the effects of quaternization of the
bis(phosphines) by the addition of an oxygen or sul-
fur atom on the geometry of the bis(phosphine chal-
cogenides) compared to the bis(phosphines).
Mass Spectrometry and IR Spectroscopy
For further structural characterization, compounds
2a, 2b, 2d–f, and 3f were subjected to a EI mass spec-
trometric investigation (see Table 2). Molecular ions
ם
ם
[M] or [M-H] were observed for all the products.
Fragmentation occurred mainly by stepwise loss of
the alkyl or aryl groups via P–C bond cleavage or
elimination of the chalcogenide atoms. In the spec-
tra of compounds 2a, 2b, 2e, and 2f, the ions that
resulted from loss of one phosphinyl group formed
the base peak (100% intensity), whereas in 2d and
ם
ם
3f the ions [M-R] and [M-2X-2R] were observed
with 100% intensity.
In the IR spectra of the bis(phosphine oxides),
2a, 2b, and 2d–f, characteristic strong absorption
מ1
bands were observed between 1170 cm (2e) and
מ1
1195 cm
(2f). The bis(phosphine sulfide) 3f
showed typical absorptions at 663 (w) and 644 (m)
cmמ1 [15].
As in the bis(phosphines), the twisting of the
molecules is evident in the torsion angles P1–
TABLE 2 Mass Spectrometric data of 1,8-phosphinyl-substituted naphthalenes 2a, 2b, 2d–f (X ס O) and the phosphine
sulfide 3f (X ס S)
2a
2b
2d
2e
2f
3f
Fragment
R ס RЈ ס CH3 R ס RЈ ס C2H5 R ס RЈ ס C6H11 R ס C4H9, RЈ ס C6H5 R ס RЈ ס C6H5 R ס RЈ ס C6H5
ם
[M]
{280}
279 (6)
{336}
335 (.24)
321b (.06)
307 (45)
—
{552}
551 (0.50)
488 (0.4)
—
472 (0.2)
431 (73)
415 (2)
375b (20)
—
528 (0.6)
560 (6)
—
528 (20)
483 (1)
451 (50)
—
375 (31)
419b (33)
343b (100)
—
ם
[M-H]
—
—
[M-X]a
[M-R]a
—
265 (20)
249 (1)
—
469 (100)
451 (2.8)
435 (1.8)
ם
[M-X-R]
[M-2R]
[M-X-2R]
[M-2X-R]
[M-2X-2R]
[M-P(:X)RRЈ]
[M-2R-RЈ]
[MЈ-R]
[MЈ-R-X]
—
279a (2)
—
387b (11)
—
—
—
—
ם
ם
—
—
—
—
—
—
ם
—
—
—
—
ם
203c (100)
235 (ꢂ1)
189b (4)
—
231 (100)
250a (4)
203a (2)
—
173 (15)
157 (11)
128b (4)
339 (79)
307 (100)
297 (44)
251b (46)
233 (30)
173 (30)
157 (12)
—
327 (100)
ם
305b (25)
—
249 (24)
—
—
—
—
—
—
—
ם
םd
—
—
—
—
—
םd
םd
[MЈ-R-RЈ]
[MЈ-R-RЈ-X]
[M-2P(:X)R2]
173 (16)
157 (3)
127 (3)
—
—
—
םd
ם
Note: { }, not observed; bold, base peak; intensity indicated by values in parentheses.
aPresumably H-transfer (ם 1H) and alkene-elimination.
bם 1H.
cמ 1H.
d[MЈ] ס [M-P(:X)RRЈ].

Oxidation Reactions of 1,8-Bis(phosphino)naphthalenes 107
and a twist into a nonplanar conformation. Mean
deviations from the best plane (C1 to C10) range
from 8.6 pm in 2a to 13.0 pm in 3f. The peri-carbon
atoms C1 and C8 and also C4 and C5 show a dis-
placement from the best plane such that each C6-ring
is distorted to a flattened half boat. Bond angle de-
formation is indicated by a widening of the C1–C9–
C8 angle (see Table 4), which deviates significantly
from the standard C–C–C bond angle in naphthalene
(119–121ꢀ [17]).
The conformations of the phosphinyl and the
thiophosphinyl groups relative to the naphthalene
plane (Figure 3) can be described by the orientation
of the PסX bonds toward that plane. Torsion angles
X–P1–C1–C2 and X–P2–C8–C7 of 180ꢀ indicate a bi-
secting conformation [4a] of the P(:X)R2 groups rela-
tive to the C10-plane, whereas angles of about 120ꢀ
indicate an eclipsed conformation (Scheme 6 and
Table 5). These angles range from מ149.7 (2)ꢀ at P1
in 2f to מ168.00 (13)ꢀ in 2e. In the case of 2e, the
conformation is approximately bisecting, in the
other molecules the conformation lies between the
ideal forms bisecting and eclipsed. In all four mole-
cules, the chalcogenide atoms point to opposite faces
of the naphthalene plane.
The CPC bond angles vary from 101.8(1)ꢀ (C17–
P1–C11 in 2f) to 105.84(8)ꢀ (C11–P–C7 in 2e). P–
C(sp2) and P–C(sp3) bond lengths are normal [18];
the longer P–C(tBu) bond in 2e [186.6(2) pm] lies in
the usual range for P–C(tBu) bonds found from a
CCDC search [17] (11 hits, mean value: 185.5 pm,
min.: 182.2 pm, max.: 187 pm).
In all four structures, nonclassical hydrogen
bonds (C–H•••X) were found (Table 6). In 2f, there
is a short [250 pm] and approximately linear [170.6ꢀ]
hydrogen bond. In 3f, because sulfur is a weaker ac-
ceptor, only a weak C–H•••S contact [294.0 pm,
143.2ꢀ] was observed, which may be the reason for
the nonisostructural crystallization.
In summary, the structures of the bis(phosphine
chalcogenides) 2a, 2e, 2f, and 3f are more strongly
distorted than those of the corresponding
bis(phosphines) 1a/1a؅, 1e, and 1f. A comparison be-
tween the oxidized and the sulfurated compounds 2f
and 3f shows a significantly bigger distortion in 3f.
As in the case of the bis(phosphines), there is no sim-
ple correlation between the type and extent of dis-
tortion and the steric bulk of the organic substitu-
ents on phosphorus in the bis(phosphine
chalcogenides).
FIGURE 1 Molecular structure of 2e in the crystal; (S,S)-
enantiomer.
C1•••C8–P2, P1–C1–C9–C8, and P2–C8–C9–C1, as
well as in the displacement of the phosphorus atoms
to opposite faces of the best naphthalene plane (Ta-
ble 3); the pseudo-torsion angles P1–C1•••C8–P2,
for example, range from 39.8 (1)ꢀ in the
bis(diphenylphosphine oxide) 2f to values as high as
63.8 (1)ꢀ in the bis(tert-butylphenylphosphine oxide)
(S,S)-2e, the largest value that has been observed in
1,8-P,P-disubstituted naphthalenes to date. The out-
of-plane distortion in the bis(dimethylphosphine ox-
ide) 2a is unexpectedly large, compared to the
bis(diphenylphosphine oxide) 2f (Table 3). It should
be noted that the pseudo-torsion angle P1–C1•••C8–
P2 in 2a [48.45 (7)ꢀ] is even larger than the angle in
the bulky bis(tert-butylphenylphosphine) 1e [46.54
(7)ꢀ]. Again, there seems to be no simple correlation
between out-of-plane distortion in the bis(phosphine
oxides) and the steric bulk of the P(:O)RRЈ groups.
Apart from the out-of-plane distortion, in-plane dis-
tortion of the P(:X)RRЈ groups, which is indicated by
a widening of the bay angles P1–C1–C9, P2–C8–C9
and C1–C9–C8 is apparent in 2a, 2f, and 3f (Table 4).
Widening of the bay angles was also observed in 1a/
1aЈ and 1f. Again, there is no obvious trend relating
in-plane distortion and steric bulk of the P(:X)R2
groups. It should be noted that in 2e the angles P1–
C1–C9 and P2–C8–C9 are smaller than the ideal sp2
angle of 120ꢀ. This observation was also made for the
corresponding bis(phosphine) 1e.
EXPERIMENTAL
The displacement of the phosphinyl substituents
is also associated with the distortion of the usually
planar and rigid C10-unit by bond angle deformation
General experimental methods were as described
previously [4a]. The 1,8-bis(diorganophosphino)

108 Karac¸ar et al.
FIGURE 2 Molecular structures of 2a, (S,S)-2e, 2f, and 3f viewed along the C2•••C9•••C7 axis to illustrate the amount of
out-of-plane displacement of the P(:X)R2 groups (X ס O, S).
naphthalenes 1a–f were prepared by literature meth-
ods [3a,4a,7]. H2O2 •(H2N)2C(:O) was obtained from
Merck-Schuchhardt, Darmstadt, and elemental, grey
selenium (99.5%) from Acros Chemicals, Gelnhau-
sen, Germany. NMR: Bruker AC 200 (1H: 200.1 MHz,
13C: 50.3 MHz, 31P: 81.0 MHz), Bruker AM 400 and
DRX 400 (1H: 400.13 MHz, 13C: 100.61 MHz). CDCl3
was used throughout as solvent. Reference sub-
ments (DRX 400) (2e); mc denotes a complex mul-
tiplet. Elemental analyses were carried out by Anal-
ytisches
Laboratorium
des
Instituts
fu¨r
Anorganische und Analytische Chemie, Analytisches
Laboratorium des Instituts fu¨r Pharmazeutische
Chemie der Technischen Universita¨t Braunschweig,
and by Pracownia Mikroanalizy, Center of Molecular
and Macromolecular Studies, Polish Academy of
Sciences, Ło´dz´, Poland.
stances were SiMe4 (TMS) or CHCl3 (int.) at dH
ס
7.25 for 1H and dC ס 77.05 for 13C NMR spectra and
85% H3PO4 (ext.) at dP ס 0 for 31P NMR spectra. The
atom numbering (C, H, P) is summarized in Scheme
5. Assignments were supported by CH correlation
spectroscopy (COSY) and COLOC experiments (AM
400) (2f, 3f) or HC HMBC and HC HMQC experi-
Preparation of 1,8-Bis(diphenylphosphinyl)
naphthalene (dppnO2) (2f).
Dppn 1f (0.6 g, 1.21 mmol) was stored in air. After
three weeks, the intensive yellow color had faded,

Oxidation Reactions of 1,8-Bis(phosphino)naphthalenes 109
FIGURE 3 Molecular structures of 2a, (S,S)-2e, 2f, and 3f viewed along the C9–C10 bond to illustrate the amount of out-of-
plane displacement of the P(:X)R2 groups (X ס O, S), their conformation relative to the naphthalene ring, and the exact or
approximate C2 symmetry. Because of crystallographic symmetry, the bond is labeled as C5–C6 on the right-hand side of the
figure.
and a colorless product was formed. After three
months, oxidation was almost complete, as was ob-
served from the 31P{1H} NMR spectrum. In order to
take the oxidation to completion, the crude product
was dissolved in 10 mL of dichloromethane. The so-
lution was saturated with air and stirred at room
temperature for 12 hours. After removal of the sol-
vent in vacuo 0.611 g (1.16 mmol, 96%) of a color-
less, crystalline solid were obtained (m.p. ꢃ 230ꢀC,
decomp.). Alternatively, 2f can also be prepared by
oxidation of 1f with (1) H2O2 •(H2N)2C(:O) or (2)
aqueous H2O2: (1) To a solution of 0.490 g (0.987
mmol) dppn in 15 mL of dichloromethane, 0.230 g
(2.4 mmol, 2.5 eq) of H2O2 •(H2N)2C(:O) was added
in small portions with stirring at room temperature.
The mixture was stirred overnight. After removal of
the urea adduct by filtration and following removal
of the solvent, 0.507 g (0.96 mmol, 97%) of a color-
less powder was obtained. (2) To a solution of 0.624
g (1.26 mmol) dppn in 20 mL of dichloromethane,
0.5 mL of aqueous H2O2 (35%) was added at room
temperature. After stirring at room temperature
overnight, drying with Na2SO4 (ca. 3 g), and remov-
ing the solvent, 0.648 g (1.23 mmol, 97%) of a col-
orless powder were obtained. Single crystals suitable
for an X-ray structure analysis were obtained from
a saturated solution of 2f in dichloromethane/n-hex-
ane by slow evaporation at room temperature. See
Table 1 for 13C and 31P NMR data and Scheme 5 for
the numbering of the H- and C-atoms. 1H NMR (400

110 Karac¸ar et al.
TABLE 3 Out-Of-Plane Distortion in Bis(phosphines) 1a/1aЈa [4b], 1e [4a], and 1f [3c], in Their Oxides 2a, 2e, and 2f, and in
dppnS2 (3f), as Indicated by the Torsion Angles P1–C1•••C8-P2, P1–C1–C9–C8, P2–C8–C9–C1, and the Out-Of-Plane Dis-
placement of P1 and P2 from the Least-Squares Plane of the Naphthalene Carbon Atoms
Out-Of-
Plane Disp.
Mean
Devn.
Nonbonded
Distances
Torsion Angles
Compound P1–C1•••C8–P2 P1–C1–C9–C8 P2–C8–C9–C1
P1
P2
C1 to C10 P1•••P2 X1•••X2b
1aa
1aЈ
1e
30.7 (2)
20.0 (2)
46.5 (1)
17.7
18.0 (4)
11.9 (2)
26.7 (2)
13.4 (7)
18.0 (4)
11.9 (2)
26.5 (2)
7.7 (7)
ם37.8 (5) מ37.8 (5)
ם29.7 (6) מ29.7 (6)
ם88.9 (2) מ91.2 (2)
1.0
ꢂ0.1
9.6
307.0 (1)
303.6 (1)
305.6 (1)
305.2
—
—
—
—
1fc
ם34
מ50
6.6
2a
2e
2f
מ48.5 (1)
63.8 (1)
39.8 (1)
מ29.4 (4)
36.5 (1)
22.2 (4)
מ28.1 (4)
מ36.5 (1)d
25.5 (4)
94.1 (3) מ93.9 (3)
מ121.1 (1)
10.2
14.6
7.8
343.2 (1) 293.0 (3)
347.9 (1) 298.3 (2)
337.9 (1) 291.9 (3)
374.6 (1) 368.5 (6)
121.1 (1)d
70.3 (3) מ81.5 (3)
107.8 (1) מ107.8 (1)d
3f
מ53.4 (1)
מ32.4 (1)
32.4 (1)d
14.9
Note: Angles in degrees; distances in pm.
aThe structure of 1,8-bis(dimethylphosphino)naphthaleneconsists of two independent molecules denoted as 1a and 1aЈ.
b2a, 2e, 2f: X ס O; 3f: X ס S.
cValues taken from Ref. [3c] or calculated from deposited data; standard deviations were not available for some values.
dBy symmetry.
TABLE 4 In-Plane Distortions in Bis(phosphines) 1a/1aЈa
[4b], 1e [4a], and 1f [3c], in Their Oxides 2a, 2e, and 2f, and
in dppnS2 (3f) as Indicated by the Bay Angles P1–C1–C9,
P2–C8–C9, and C1–C9–C8 (in ꢀ)
TABLE 5 Conformations of the P(:X)R2 Groups, Relative to
the C10-Plane, Described by the Orientation of the PסX
Bonds (ꢀ)
Compound
Torsion Angle
Compound
P1–C1–C9
P2–C8–C9
C1–C9–C8
2a
2e
2f
3f
1a
1aЈ
1e
1f
121.6 (4)b
123.1 (9)b
118.1 (1)
124.5 (3)
121.6 (4)c
123.1 (9)c
118.4 (1)
123.0 (4)
125.5 (6)
125.5 (6)
123.5 (1)
125.3
X–P1–C1–C2 157.5 (2) מ168.00 (13) מ149.7 (2) 158.42 (7)
X–P2–C8–C7 162.5 (2) מ168.00 (13)a מ153.8 (2) 158.42 (7)a
aBy symmetry.
2a
2e
2f
123.0 (2)
117.8 (1)b
123.2 (2)
125.1 (1)b
121.9 (2)
117.8 (1)c
124.1 (2)
125.1 (1)c
126.3 (3)
126.0 (2)
127.3 (3)
128.1 (1)
MHz): d ס 7.30–7.44 [mc, 14H, H-o or H-m, H-p, and
H-3], 7.48 [mc, 8H, H-o or H-m], 7.71 [mc (ꢁ ddd),
3J(H2H3) ס 7.2 Hz, 4J(H2H4) ס 1.0 Hz, 2H, H-2], 7.90
[mc ꢁ dd, 3J(H3H4) ꢁ 8.1 Hz, 4J(H2H4) ꢁ 1.3 Hz, 2H,
H-4]; IR (KBr): m˜(cmמ1) ס 3052 (w), 1556 (w), 1482
(w), 1435 (m), 1322 (w), 1217 (w, sh), 1195 (vs, mPסO),
1158 (w), 1112 (m), 1101 (m), 891 (m), 822 (w), 772
(m), 748 (m), 713 (s), 692 (s), 566 (s), 520 (s), 434
(m); EI-MS: see Table 2; Anal. found: C, 77.03%; H,
5.17%; P, 11.64%. Calcd for C34H26O2P2 (528.53): C,
77.27%; H, 4.96%; P, 11.72%. The preparation of
compounds 2a, 2b, 2d, and 2e was conducted anal-
ogously to the preparation of 2f [method (1)]:
3f
a1a and 1aЈ denote two independent molecules.
bLabelled as P1–C1–C6 in Figures 1–3 because of crystallographic
symmetry.
cBy symmetry.
1,8-Bis(dimethylphosphinyl)naphthalene (2a)
Starting from 2.17
bis(dimethylphosphino)naphthalene (1a), CH2Cl2
(10 mL) and 1.80 (19 mmol, 2.2 eq) of
g
(8.74 mmol) of 1,8-
g
H2O2 •(H2N)2C(:O), 2.11 g (7.53 mmol, 86%) of a col-
orless solid (m.p. ꢃ 200ꢀC, decomp.) were obtained
by recrystallization from CH2Cl2/Et2O. Crystals suit-
SCHEME 6 Idealized eclipsed (a) and bisecting (b) confor-
mations of 1,8-bis(phosphinyl)naphthalenes. Numerical val-
ues are pseudo torsion angles (see text).

Oxidation Reactions of 1,8-Bis(phosphino)naphthalenes 111
TABLE 6 Non-Classical Hydrogen Bonds for 2a, 2e, 2f and 3f [pm] and [ꢀ]
Compound
D–H•••A
d(D–H) d(H•••A) d(D•••A) ꢂ(DHA)
Sym. Transformations for Equiv. Atoms
2a
2e
C11-H11B•••O1#1
C6-H6•••O2#2
C3-H3•••O#1
C14-H14•••O#2
C27-H27•••O1#1
C13-H13•••S#1
98
95
95
95
95
95
239
251
260
252
250
294
335.4 (4)
331.2 (4)
351.0 (2)
343.5 (2)
344.1 (4)
374.2 (1)
168.5
142.7
159.9
161.1
170.6
143.2
#1 0.5מx, מ0.5םy,.z #2 מx, 0.5םy,.0.5מz
#1 x, מy,.0.5םz #2 x, 1מy,.0.5םz
2f
3f
#1 מx, y,.0.5מz
#1 2.5מx, 0.5מy,.1מz
able for X-ray diffraction were obtained from CDCl3
by slow evaporation of the solvent. See Table 1 for
13C and 31P NMR data and Scheme 5 for the num-
and 110 mg (1.2 mmol, 2.3 eq) H2O2 •(H2N)2C(:O),
227 mg (0.41 mmol, 82%) of a colorless solid (m.p.
153 ꢀC) were obtained by recrystallization from
CH2Cl2/Et2O. See Table 1 for 13C and 31P NMR data
and Scheme 5 for the numbering of the H- and C-
atoms. 1H NMR (400.1 MHz): d ס 0.10–4.00 [mc, 44
1
bering of the H- and C-atoms. H NMR (200 MHz):
d ס 1.78 [d, 2J(PH) ס 12.8 Hz, 12H, ␣-H, P(:O)CH3],
3
4
7.42 [mc (ꢁ ddd), J(H2H3) ꢁ 7.6 Hz, J(H2H4) ꢁ 2.0
3
3
Hz, 2 H, 2-H], 7.61 [mc (ꢁ ddd), J(H3H4) ꢁ 7.9 Hz,
3J(H2H3) ꢁ 7.0, 4J(PH) ꢁ 1.1 Hz, 2 H, 3-H], 7.81 [mc
H, cyclohexyl-CH and -CH2], 7.43 [mc (ꢁ t), J(HH)
ꢁ 6.5 Hz, 2H, 3-H], 7.66 [mc, br, 2H, 2-H], 7.80 [mc
3
4
מ1
(ꢁ dq), J(H3H4) ꢁ 8.0 Hz, J(H2H4) ꢁ 1.6 Hz, 2 H,
4-H]; IR (KBr): m˜ (cmמ1) ס 3053 (w), 3023 (m), 2972
(m), 2912 (m), 1487 (m), 1293 (s), 1189 (s, mPסO), 1166
(s), 1060 (w), 1005 (w), 946 (s), 859 (m), 831 (s), 727
(m), 463 (w), 406 (m), 360 (m), 309 (m); EI-MS: see
Table 2; Anal. found: C, 59.25%; H, 6.57%. Calcd. for
C14H18O2P2 (280.24): C, 60.00%; H, 6.47%.
(ꢁ d), 3J(HH) ꢁ 7.7 Hz, 2 H, 4-H]; IR (KBr): m˜ (cm
)
ס 3048 (w), 2930 (vs), 2850 (vs), 1448 (m), 1277 (w),
1215 (w), 1181 (m, mPסO), 1106 (w), 885 (w), 772 (w),
564 (w); EI-MS: see Table 2; Anal. found: C, 73.33%;
H, 9.24%. Calcd for C34H50O2P2 (552.72): C, 73.88%;
H, 9.12%.
rac-1,8-Bis(phenyl-tert-
butylphosphinyl)naphthalene (2e)
1,8-Bis(diethylphosphinyl)naphthalene (2b)
From 302 mg (0.99 mmol) of 1,8-bis(diethyl-
phosphino)naphthalene (1b), CH2Cl2 (5 mL), and
200 mg (2.13 mmol, 2.15 eq) H2O2 •(H2N)2C(:O), 246
mg (0.73 mmol, 74%) of a colorless solid (m.p.
164ꢀC) were obtained by recrystallization from
CH2Cl2/Et2O. See Table 1 for 13C and 31P NMR data
and Scheme 5 for the numbering of the H- and C-
From 0.158 g (0.35 mmol) rac-1,8-bis(phenyl-tert-bu-
tylphosphino)naphthalene (1e), CH2Cl2 (5 mL), and
0.98 g (1 mmol, 1.4 eq) H2O2 •(H2N)2C(:O), 0.140 g
(0.28 mmol, 80%) of a colorless solid (m.p. 325–
330ꢀC, decomp.) were obtained by recrystallization
from CH2Cl2/Et2O. See Table 1 for 13C and 31P NMR
data and Scheme 5 for the numbering of the H- and
C-atoms. 1H NMR (200 MHz): d ס 0.57 [d, J(PH) ס
13.6 Hz, 18 H, C(CH3)3, b-H], 7.50–7.60 [mc, 8 H,
arom. H], 7.93 [mc (ꢁ dd), 3J(H3H4) ס 8.3 Hz,
3J(H2H3) ס 7.1 Hz, 2 H, 3-H], 8.06–8.17 [mc, 6 H,
arom. H]; IR (KBr): m˜ (cmמ1) ס 3085 (w), 3055 (m),
2981 (s), 2947 (s), 2900 (m), 2865 (m), 1472 (m),
1442 (m), 1360 (w), 1170 (s, mPסO), 1106 (m), 1009
(w), 878 (w), 750 (m), 691 (m), 611 (m), 566 (m), 537
(m), 513 (m), 397 (w); EI-MS: see Table 2; Anal.
found: C, 71.85%; H, 7.41%; P, 11.67%. Calcd for
C30H34O2P2 (488.55): C, 73.76%; H, 7.01%; P, 12.68%.
1
atoms. H NMR (200 MHz): d ס 0.89 [mc (ꢁdt),
J(PH) ס 16.3 Hz, J(HH) ס 7.6 Hz, 12 H, CH2CH3, b-
H (AAЈ-part)], 2.15 [mc, 8 H, CH2CH3, ␣-H (BBЈ-
part)], 7.41 [mc (ꢁ ddd), 3J(H2H3) ꢁ 7.5 Hz, 4J(H2H4)
ꢁ 2.3 Hz, 2 H, 2-H], 7.55 [mc (ꢁ ddd), 3J(H3H4) ꢁ 7.7
Hz, 3J(H2H3) ꢁ 7.0, 2 H, 3-H], 7.80 [mc (ꢁ dq),
4
3J(H3H4) ꢁ 7.9 Hz, J(H2H4) ꢁ 1.5 Hz, 2 H, 4-H]; 31
P
NMR (CDCl3): d ס 48.9 [mc (ꢁvoctet), J ꢁ 14 Hz]; IR
(KBr): m˜ (cmמ1) ס 3052 (w), 2966 (vs), 2933 (s), 2912
(m), 2878 (s), 1938 (m), 1456 (m), 1322 (w), 1179 (s,
mPסO), 1034 (m), 891 (m), 829 (m); EI-MS: see Table
2; Anal. found: C, 63.79%; H, 7.75%. Calcd. for
C18H26O2P2 (336.35): C, 64.28%; H, 7.79%.
Formation of 1,8-
Bis(diisopropylphosphinyl)naphthalene (2c).
1,8-Bis(dicyclohexylphosphinyl)naphthalene
(2d)
A small portion of H2O2 •(H2N)2C(:O) was added to
an NMR sample of 1,8-bis(diisopropylphosphino)
naphthalene (1c) dissolved in CDCl3. The resulting
From 260 mg (0.5 mmol) 1,8-bis(dicyclo-
hexylphosphino)naphthalene (1d), CH2Cl2 (5 mL)

112 Karac¸ar et al.
mixture was investigated by 31P{1H} NMR spectros-
(KBr): m˜ (cmמ1): 3046 (w), 1479 (w), 1437 (s), 1304
(w), 1096 (m), 879 (w), 817 (w), 766 (m), 742 (m),
721 (s), 700 (m), 663 (w), 644 (m), 616 (w), 538 (w),
521 (w), 498 (s), 454 (w), 423 (m); EI-MS: see Table
2; Anal. found: C, 73.00%; H, 4.51%; P, 10.94%; S,
11.53%. Calcd for C34H26P2S2 (560.66): C, 72.84%; H,
4.67%; P, 11.05%; S 11.44%.
copy. 31P{1H} NMR: d ס 52.4.
Preparation of 1,8-
Bis(diphenylthiophosphinyl)naphthalene (3f)
Dppn 1f (1.24 g, 2.5 mmol) and 0.2 g (6.2 mmol, 2.5
eq) of elemental sulfur were slurried in 20 mL of tol-
uene and heated under reflux for 17 hours. The re-
action was monitored by 31P{1H} NMR spectroscopy.
In the first step, the phosphine sulfide 3fЈ was
formed, which reacted to the bis(phosphine sulfide)
3f upon heating in the presence of sulfur (Scheme
4a). After removal of the solvent by rotary evapora-
tion, a yellow solid was obtained, which was taken
up in dry methanol. The crude product was purified
by recrystallization from a 1:1 mixture of CH2Cl2 and
n-hexane. Yield: 0.66 g (1.18 mmol, 47%) of a col-
orless solid (m.p. 237–239ꢀC). See Table 1 for 13C and
31P NMR data and Scheme 5 for the numbering of
the H- and C-atoms. 1H NMR (400 MHz): d ס 7.10–
Reaction of Dppn with Elemental Selenium
Dppn 1f (0.80 g, 1.60 mmol), grey selenium (0.30 g,
3.80 mmol), and a catalytic amount of AlCl3 were
slurried in 20 mL of toluene and heated under reflux
for 23 hours. The reaction was monitored by 31P{1H}
NMR spectroscopy. In the first step, the phosphine
selenide 4fЈ was formed, which did not react to the
bis(phosphine selenide) 4f upon heating in the pres-
ence of an excess of selenium (Scheme 4b). A cata-
lytic amount of AIBN was added, and the mixture
was refluxed for 7 hours. No further reactions were
observed.
3
7.25 [mc, 12 H, H-m, H-p], 7.30 [mc (ꢁ dt), J(H2H3)
3
ꢁ 6.9 Hz, J(H3H4) ꢁ 8.3 Hz, 2 H, H-3], 7.40 [mc, 8
Reaction of Dppn with Elemental Tellurium
H, H-o], 7.76 [mc (ꢁ ddd), 3J(H2H3) ס 7.1 Hz,
4J(H2H4) not resolved, 2 H, H-2], 7.85 [mc (ꢁ dq),
A suspension of 0.15 g (0.30 mmol) dppn (1f), 0.038
g (0.30 mmol) elemental tellurium, and a catalytic
4
3J(H3H4) ꢁ 8.0 Hz, J(H2H4) ꢁ 1.0 Hz, 2 H, H-4]; IR
TABLE 7 Crystallographic Data for 2a, 2e, 2f, and 3f
Compound
2a
2e
2f
3f
Formula
Mr
C14H18O2P2
280.22
C30H34O2P2
488.51
C34H26O2P2
528.49
C34H26P2S2
560.61
Crystal habit
Crystal size (mm)
Temperature (ꢀC)
Crystal system
Space group
Cell constants
a (pm)
colourless prism
0.75 ן 0.50 ן 0.30
מ100
orthorhombic
Pbca
colourless, irregular
0.65 ן 0.65 ן 0.50
מ100
monoclinic
C2/c
colourless tablet
0.70 ן 0.60 ן 0.30
מ130
monoclinic
C2/c
colourless prism
0.44 ן 0.22 ן 0.15
מ130
monoclinic
C2/c
1655.94(14)
1011.15(10)
1683.7(2)
90
2.8192(5)
8
1.320
0.300
1184
24.99
1846.0(2)
1159.54(12)
1229.36(12)
98.954(8)
2.5994(5)
4
1.248
0.193
1040
25.00
3459.0(8)
870.2(2)
1921.9(4)
112.38(2)
5.349(2)
8
1.312
0.193
2208
25.04
1162.32(12)
1522.62(16)
1573.67(16)
93.63(3)
2.7794(5)
4
1.340
0.330
1168
30.55
b (pm)
c (pm)
b (ꢀ)
U (nm3)
Z
מ3
Dx (Mg m
)
מ1
l (mm
F(000)
2hmax (ꢀ)
)
No. of reflections:
Measured
2586
2462
4568
2286
8709
4729
11797
4264
0.0495
0.0879
0.0321
173
1.047
ꢂ0.001
439
Independent
Rint
0.019
0.1241
0.0473
167
1.035
ꢂ0.001
379
0.0296
0.0877
0.0342
158
0.989
ꢂ0.001
340
0.0417
0.1281
0.0523
343
1.044
ꢂ0.001
476
wR(F2, all refl.)
R(F, ꢃ4r(F))
No. of parameters
S
Max. D/r
Max. Dq (e nm
מ3
)

Oxidation Reactions of 1,8-Bis(phosphino)naphthalenes 113
Iroff, L. D.; Sjo¨strand, U.; Mislow, K. J Am Chem Soc
1980, 102, 99; (c) Anet, F. A. L.; Donovan, D.; Sjo¨s-
trand, U.; Cozzi, F.; Mislow, K. J Am Chem Soc 1980,
102, 1748; (d) Hounshell, W. D.; Anet, F. A. L.; Cozzi,
F.; Damewood, J. R., Jr.; Johnson, C. A.; Sjo¨strand, U.;
Mislow, K. J Am Chem Soc 1980, 102, 5941; (e)
Schro¨ck, R.; Angermaier, K.; Sladek, A.; Schmidbaur,
H. Organometallics 1994, 13, 3399; (f) Leger, J. M.;
Grignon-Dubois, M.; Laguerre, M. Acta Cryst 1995,
C51, 1665; (g) Wozniak, K.; He, H.; Klinowski, J.;
Barr, T. L.; Hardcastle, S. E. J Phys Chem 1996, 100,
11, 408.
amount of pyridine in 20 mL of toluene was heated
at reflux for 25 hours. The reaction was monitored
by 31P{1H} NMR spectroscopy.
Crystal Structure Analyses
Crystal data are summarized in Table 7.
Data Collection and Reduction. Crystals were
mounted on glass fibers in inert oil and transferred
to the cold gas stream of the diffractometer (Siemens
P4 for 2a and 2e, Stoe STADI-4 for 2f, both with LT-
2 low temperature attachment, and Bruker SMART
1000 CCD with LT-3 low temperature attachment for
3f). The orientation matrix for 2a and 2e was refined
from setting angles of 70 (60) reflections in the 2h
range 5–25ꢀ. The cell constants for 2f were refined
from עx angles of 52 reflections in the 2h range 20–
23ꢀ and for 3f from 5973 reflections in the 2h range
2–60ꢀ (monochromated MoK␣ radiation).
[3] See, for example: 31P, (a) Costa, T.; Schmidbaur, H.
Chem Ber 1982, 115, 1374; (b) Berger, S.; Braun, S.;
Kalinowski, H.-O. NMR-Spektroskopie von Nicht-
metallen; 31P-NMR-Spektroskopie; Thieme: Stutt-
gart, New York, 1992; Vol. 3, p 145; (c) Jackson, R. D.;
James, S.; Orpen, A. G.; Pringle, P. G. J Organomet
Chem 1993, 458, C3; 125Te (d) Fujihara, H.; Ishitani,
H.; Takaguchi, Y.; Furukawa, N. Chem Lett 1995, 571.
[4] (a) Karac¸ar, A.; Tho¨nnessen, H.; Jones, P. G.; Bartsch,
R.; Schmutzler, R. Heteroatom Chem 1997, 8, 539;
(b) Jones, P. G.; Tho¨nnessen, H.; Karac¸ar, A.; Schmut-
zler, R. Acta Cryst 1997, C53, 1119; (c) Karac¸ar, A.;
Tho¨nnessen, H.; Jones, P. G.; Bartsch, R.; Schmutzler,
R. Chem Ber Recueil 1997, 130, 1485.
Structure Solution and Refinement. The struc-
tures were solved by direct methods and refined an-
isotropically on F2 (program system: SHELXL-93 for
2a, 2e, and 2f and SHELXL-97 for 3f, G. M. Sheld-
rick, University of Go¨ttingen). H atoms were in-
cluded using a riding model or rigid methyl groups.
[5] Alder, R. W. Chem Rev 1989, 89, 1215.
[6] See Ref. [3c] and references cited therein.
[7] van Soolingen, J.; de Lang, R.-J.; den Besten, R.; Klu-
sener, P. A. A.; Veldman, N.; Spek, A. L.; Brandsma,
L. Synth Commun 1995, 25, 1741.
[8] Hartley, F. R. Ed. The Chemistry of Organophospho-
rus Compounds, Wiley: New York, 1992, Vol. 1, Chap-
ter 3.
[9] See, for example, (a) Jones, P. G.; Tho¨ne, C. Acta Crys-
tallogr C 1992, 48, 2114; (b) Matrosov, E. I.; Stari-
kova, Z. A.; Yanovsky, A. I.; Lobanov, D. I.; Aladzheva,
I. M.; Bykhovskaya, O. V.; Struchkov, Y. T.; Mastryu-
kova, T. A.; Kabachnik, M. I. J Organomet Chem
1997, 535, 121; (c) Preisenberger, M.; Bauer, A.;
Schmidbaur, H. Chem Ber Recueil 1997, 130, 955; (d)
Pilloni, G.; Longato, B.; Bandoli, G. Inorg Chim Acta
1998, 277, 163; (e) Jones, P. G.; Ahrens, B. Chem Com-
mun 1998, 2307.
מ1
Weighting schemes of the form w ס [r2(Fo2) ם
(aP)2 ם bP], with P ס (Fo2 ם 2F2c)/3 were employed.
Full details of the structure determinations have
been deposited at the Cambridge Crystallographic
Data Centre, 12 Union Rd., GB Cambridge CB2 1EZ,
under the numbers 148131 (2a), 148132 (2e), 148133
(2f), and 148134 (3f). Copies may be obtained free
of charge on application to the Director (Telefax: Int
ם12 23 33 60 33; e-mail: deposit@ccdc.cam.ac.uk).
[10] See Ref. [8]; ch. 8.
ACKNOWLEDGMENTS
[11] Grim, S. O.; Walton, E. D. Inorg Chem 1980, 19, 1982.
[12] du Mont, W.-W.; Hensel, R.; Kubiniok, S.; Lange, L.
in The Chemistry of Organic Selenium and Tellurium
Compounds; Patai, S., Ed.; Wiley: New York, 1987;
Vol. 2, Chapter 15.
[13] Baker, M. J.; Giles, M. F.; Orpen, A. G.; Taylor, M. J.;
Watt, R. J. J Chem Soc Chem Commun 1995, 197.
[14] Karac¸ar, A.; Freytag, M.; Tho¨nnessen, H.; Omelan-
czuk, J.; Jones, P. G.; Bartsch, R.; Schmutzler, R. Z
Anorg Allg Chem, 2000, 626, 2361.
A. Karac¸ar is grateful to the Hoechst AG for a
maintenance grant, and J. Omelanczuk thanks the
Alexander von Humboldt-Stiftung. The gifts of
chemicals by Chemetall AG, Basf AG, Bayer AG, and
Hoechst AG are gratefully acknowledged. Professor
W.-W. du Mont is thanked for helpful discussion.
[15] See Ref. [8]; Chapter 5.
[16] Bondi, A. J Phys Chem 1964, 68, 441.
[17] Allen, F. H.; Kennard, O. Chem Des Autom News
1993, 8, 31.
[18] Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer,
L.; Orpen, A. G.; Taylor, R. J Chem Soc Perkin Trans
2 1987, S1.
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