peri-interactions in naphthalenes, 6 [1]. On hypercoordination of phosphorus in 8-dialkylamino-naphth-1-yl phosphonium salts

Article abstract of DOI:10.1515/znb-2002-0102

Under favourable conditions, the phosphorus centres in tetraorganophosphonium cations are sufficiently electrophilic to become hypercoordinate by reaction with strong nucleophiles. However, as a peri substituent at the naphthalene system, such a centre proved to be unable to induce the nitrogen of a peri-bound dialkylamino group to bond formation. The distortion of the naphthalene skeleton revealed by X-ray structure determination of four 8-dialkylamino-naphth-1-yl phosphonium salts does not exhibit the criteria of N-P bond formation but rather those of intersubstituent repulsion.

Full text of DOI:10.1515/znb-2002-0102

peri-Interactions in Naphthalenes, 6 [1]. On Hypercoordination of
Phosphorus in 8-Dialkylamino-naphth-1-yl Phosphonium Salts
Gu¨nter Paulus Schiemenza, Simon Po¨rksena, Paulina M. Dominiakb, and Krzysztof Wozniakb
a
Institute of Organic Chemistry, University of Kiel, D-24098 Kiel, Germany
b Chemistry Department, Warsaw University, 02 093 Warszawa, ul. Pasteura 1, Poland
Reprint requests to Prof. Dr. G. P. Schiemenz. Fax: +49 (0)431 880 1558.
Z. Naturforsch. 57 b, 8–18 (2002); received August 2, 2001
peri-Naphthalenes, Hypercoordination, Steric Effects
Under favourable conditions, the phosphorus centres in tetraorganophosphonium cations
are sufficiently electrophilic to become hypercoordinate by reaction with strong nucleophiles.
However, as a peri substituent at the naphthalene system, such a centre proved to be unable
to induce the nitrogen of a peri-bound dialkylamino group to bond formation. The distortion
of the naphthalene skeleton revealed by X-ray structure determination of four 8-dialkylamino-
naphth-1-yl phosphonium salts does not exhibit the criteria of N-P bond formation but rather
those of intersubstituent repulsion.
Introduction
Substituent interactions in peri-substituted naph-
thalenes and related systems with rigid geome-
tries presently attract much interest [2]. The con-
sequences of steric hindrance as well as the pos-
sibilities of electronic interactions (including, e. g.,
through space coupling of NMR-active nuclei [3])
have been investigated. A special aspect in this area
is the bond formingprocess between nucleophilic
and electrophilic substituents [4].
Fig. 1. Geometric conditions in peri-substituted naph-
thalenes.
too short to accommodate any peri substituents ex-
cept hydrogen. Steric hindrance enforces deforma-
tions of the naphthalene skeleton. These can be in-
plane and/or out-of-plane. Frequently, the in-plane
deformation is predominating[22 - 24]: the sum of
the three bay angles: S(1)-C(1)-C(9), C(1)-C(9)-
C(8) and S(2)-C(8)-C(9) will exceed 360 , the sum
of the three angles minus 360 beingthe splay angle
(3) [19, 20]. In such cases, the distance between the
peri-bound atoms S(1) and S(2) is longer than ca.
In 8-dialkylamino-naphth-1-yl phosphorus
(DAN-P) compounds (Figs 2, 5), the phosphorus
atom could conceivably become hypercoordinate as
a consequence of electron donation from nitrogen
to phosphorus. Based on various concepts of inter-
pretation contrastingconclusions have been drawn
[5 - 20]. We developed what we believe to be safe
criteria to extract information about bond formation
between peri substituents in 1,8-disubstituted naph-
thalenes from X-ray diffraction data [14, 18 - 21].
˚
˚
2.50 A [25], usually about 2.65 to ca. 3.00 A. Such
distances, as well as positive splay angles, indicate
safely steric hindrance [20]. Out-of-plane deforma-
tions, viz. one peri-substituent above, the other one
below the average naphthalene plane, provide addi-
tional evidence [26].
In a naphthalene molecule of ideal geometry (pla-
nar, all angles 120 ), the distance between the car-
˚
bon atoms 1 and 8 (and 4 and 5) is 2.47 A [20, 21].
On the other hand, covalent bonds (including
“hypervalent” ones) are quite resistant to stretch-
ing[1, 20], and the ideal peri-distance of ca.
2.47 - 2.55 A is much too longfor any ap-
preciable bondingbetween atoms of second and
third period elements [18, 20]. If a bond forms
This would also be the distance between two equal
peri substituents, d(S(1)...S(2)) (Fig. 1, 1). In cases
of unequal peri substituents (2), the ideal peri dis-
˚
˚
tance can be a little longer, e. g. d(N...P) = 2.50 A
˚
[18 - 20], d(N...Si) = 2.51 A [20, 21], d(N...Te) =
˚
2.55 A [20]. On the one hand, all these distances are
c
¨
¨
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G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
9
Fig. 2. Potential N P interaction in
DAN-phosphorus compounds.
Fig. 3. Example of an unstrained system with hypercoor-
dinate P-N bond [16, 17, 32].
Fig. 4. Hypercoordination of phosphonium phosphorus
by action of a strongnucleophile [34].
between the peri substituents, it will be much
shorter and, consequently, force the naphthalene
skeleton into distortion [1, 27 - 31]. In this case,
the sum of the three bay angles is < 360 , i. e.
overcome, the N-P bond has the same length (d(N-
˚
P) = 2.143 A [16, 17, 34]), i. e., if formed in DAN-P
the splay angle is negative (cf. 4). In hydrocar- compounds, the N-P bond will not yield to the stress
bon chemistry, examples are provided by 1,8-di- imposed by the rigid C10 skeleton and stretch, but
rather keep its length and force the C10 skeleton into
= 2.93 A, splay angle +14.7 [22]) and ace- distortion.
methyl-naphthalene (steric repulsion, d(H3C...CH3)
˚
˚
naphthene (d(H2C-CH2) = 1.54 A (as in ethane),
The question then arises to what extent the elec-
trophilicity of phosphorus, exceedingly low in phos-
phines, has to be enhanced as to permit N P bond
formation. In contrast to triphenylphosphine, the
tetraphenylphosphonium cation is sufficiently elec-
trophilic to react with strong nucleophiles, e. g.
with phenyl lithium to give pentaphenylphospho-
rane [35]. As in the case of 6b, five-membered
ringsystems are favourable for hypercoordination
so that the reaction of the spiro-phosphonium cation
8 with 2,2'-dilithiated biphenyl even yields tris(2,2'-
biphenylylene)phosphate (9) with hexacoordinate
phosphorus [36]. On the other hand, the nitrogen
atom of an aryl-dimethylamine is a comparatively
poor nucleophile.
splay angle –31.1 [27]). In the realm of DAN-
P compounds, analogous behaviour is met on
the one hand in DAN-phosphines (8-Me2NC10H6-
˚
PPh2 (5a): d(N...P) = 2.706 A, splay angle +5.3
[11, 13, 16, 17, 32]: repulsion), on the other
hand in a compound with hexacoordinate phos-
phorus, 1,1-dimethyl-2,2-bis(1,2-phenylenedioxy)-
1-azonia-2 6-phosphata-acenaphthene (6b) (d(N-
˚
P) = 2.132 A, splay angle –11.5 [20]).
Whereas DAN-phosphines with three P-C bonds
and an electron pair at phosphorus such as 5a and
10 are bad candidates for hypercoordination, the
substitution pattern at the P atom of 5b provides
optimal conditions for the formation of an extra
bond: Four oxygen atoms incorporated in two five-
The X-ray data of DAN-phosphonium salts
membered rings greatly enhance the electrophilicity would thus permit a straightforward decision: When
˚
of the phosphorus atom [33]. The N-P bond formed d(N...P) is considerably shorter than 2.50 A, viz. ca.
in the process 5b
˚
6b is obviously sufficiently 2.13 - 2.14 A, and the splay angle is negative, then
there is a N-P bond, and the phosphorus is hyperco-
the naphthalene system. In a more flexible structure, ordinate. On the other hand, d(N...P) > ca. 2.50 A,
7, in which no such energetic drawback has to be a positive splay angle and possibly out-of-plane de-
strongto pay the energetic bill of the distortion of
˚
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10
G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
respectively, are not in this order. Closer inspec-
tion of the conformations adopted in the crystals
reveals, in fact, a more complex situation. The two
alkyl groups at nitrogen are not symmetrically posi-
tioned with respect to the naphthalene plane. One of
the methyl groups of 5c, d, f and the isopropyl group
of 5e is more or less in a perpendicular position, the
(other) methyl group in a skew position in the anti-
clinal (ac) sector [38] with respect to the C(1)...C(8)
connectingline. The peri space available for the
substituents at phosphorus is thus unsymmetrically
shaped above and below the C10 plane. In 5d, the
N-C bond of the nearly perpendicular methyl group
and the P-CH3 bond are parallel, and the other N-
CH3 and the P-C(Ph) bonds are nearly so, the ethyl
group residing outside the peri space. This arrange-
ment looks reasonable in terms of steric effects.
Similarly, in 5e, the smallest of the groups attached
to phosphorus, CH3, resides at the same side of the
C10 plane as the larger group at N, CHMe2, which
deviates from orthogonality by 10 of inclination
into the ac sector [38]. In 5f, the P-C bonds adopt
directions similar to those in 5d, but the positions
of the ethyl group and of one phenyl group are in-
terconverted, the second phenyl group assuming the
position of the methyl group of 5d. Though, because
of the similar steric demand of ethyl and phenyl, this
arrangement could hardly be predicted, it is still in
line with a stereochemical rationalization. On the
other hand, in 5c the two small groups at P share
the less hindered face of the C10 plane, and the large
group is close to the perpendicular N-CH3 group.
This arrangement is hard to understand from a steric
point of view. We therefore restrict ourselves to the
conclusion that the degree of steric hindrance is
roughly the same in all four cations and that it is
stronger than in the phosphine 5a.
Fig. 5. Bis- and tris-(dimethylamino-naphthyl) phospho-
rus compounds.
formations would safely indicate steric repulsion
and the absence of N P bondinginteraction [37].
The aim of our paper is to find out whether in
8-dialkylamino-naphth-1-yl phosphorus derivatives
with a solely C-bound phosphorus atom, an onium
character of the P atom enhances its electrophilicity
sufficiently to enable it to form a hypercoordinate
bond with the neighbouring nitrogen atom.
Results and Discussion
The general result obtained from three new DAN-
phosphonium tetraphenylborates, 5c-e, and a phos-
phonium salt from our previous study [7], 5f, is
˚
clear-cut: d(N...P)ranges from2.891 (5d)to2.958 A
(5e) and is thus longer than in the correspond-
ingphosphine 5a. The splay angles range from
+5.8 (5c) to +7.6 (5f) and are likewise larger than
those of 5a. The non-bondingdistances C(1)...C(8),
˚
2.50 - 2.54 A, are somewhat longer than those in
the ideal naphthalene molecule, and the opposite
˚
peri distances C(4)...C(5), 2.39 - 2.465 A, slightly
(but consistently) shorter. The torsional angles N-
C(8)...C(1)-P, between 25 and 32 , are a measure of
a considerable out-of-plane deformation.
All data thus testify steric repulsion and are not
compatible with N P bonding. A first glimpse
at the phosphonium substituents might suggest
that steric hindrance should increase in the series
PMe2Ph < PMeEtPh < PMePh2 < PEtPh2, i. e. 5c
< 5d < 5e < 5f. The splay angles follow, indeed,
this order; however, they do not strictly corroborate
The unsymmetrical arrangement of the alkyl
groups at N implies that the electron pair is nei-
ther in the C10 plane, nor does it point towards the
P atom [39]. In fact, the angle between the elec-
tron pair and the P...N connectingline is: 5c: 43.4 ;
5d: 47.7 ; 5e: 46.5 ; 5f: 44.4/44.9 , a fact which
would be hard to reconcile with electron donation
from N to P.
The alternative interpretation in favour of “a weak
this expectation, because the out-of-plane distortion dative N P bondinginteraction” [40 - 42] would
does not regularly follow this trend (31.5, 25, 29, rest on two presuppositions which, in our opinion,
25/31 ). Likewise, the correspondingd(N...P) val-
ues, equal to 2.941, 2.891, 2.958, 2.897/2.955 A, coordinate” bond from ca. 2.13 A by ca. 0.80 A is
are untenable: a) that the stretchingof a N-P “hyper-
˚
˚
˚
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G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
Table 1. Selected most important structural parameters (distances in A, angles in degrees).
11
˚
Structural parameter
5c
5d
5e
5f
DBAN-Br
N1-P1
2.939(2)
124.67(18)
124.6(2)
116.6(2)
31.54(15)
2.526(4)
2.465(7)
1.427(3)
1.800(2)
–147.3(2)
89.8(2)
2.891(2)
125.57(16)
124.1(2)
116.7(2)
–25.10(14)
2.531(3)
2.460(4)
1.430(3)
1.804(2)
138.6(2)
–98.8(2)
–49.69(13)
81.05(19)
–163.87(17)
47.7
2.959(2)
124.31(17)
125.5(2)
117.1(2)
29.43(15)
2.543(3)
2.450(4)
1.430(3)
1.807(2)
–132.5(2)
99.87(18)
–76.47(17)
166.63(11)
53.32(13)
46.5
2.893(6)
124.9(6)
125.6(8)
116.8(8)
–25.5(5)
2.507(12)
2.398(15)
1.420(9)
1.791(7)
141.4(6)
–96.8(5)
73.4(4)
2.953(6)
126.1(6)
122.8(8)
118.9(8)
–31.2(5)
2.489(12)
2.447(16)
1.412(9)
1.797(7)
146.9(5)
–89.2(5)
75.2(4)
2.991(4)
122.8(4)
128.0(5)
118.6(4)
–22.6(3)
2.559(7)
2.443(10)
1.413(6)
1.908(6)
153.1(4)
–73.5(4)
–
P1-C1-C9
C1-C9-C8
N1-C8-C9
N1-C8-C1-P1
C1-C8
C4-C5
N1-C8
P1-C1
C81-N1-C8-C1
C82-N1-C8-C1
C21-P1-C1-C8
C31-P1-C1-C8
C41-P1-C1-C8
2e(N1) -N1-P1
–75.06(13)
168.78(15)
54.53(16)
43.4
–169.8(4)
–56.3(4)
44.0
-166.7(4)
-51.3(4)
44.4
–
–
59.6
2e(N1) = electron pair at N1; 2 independent molecules in the unit cell.
Fig. 6. ORTEP plots of the cations of 5c-f and of DBAN-Br showingthe labellingof relevant atoms. The projections
on the right side of this figure show the molecules as seen along the C(9)-C(10) bond.
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12
G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
possible, b) that in systems whose geometry is de- phine sulfide can aptly be described as a quaternary
fined by bond lengths and bond angles, interatomic (DAN)2 phosphonium cation in which one carbon
distances shorter than the sum of the respective van atom has been replaced by a negatively charged sul-
der Waals radii, Σ r(vdW), testify any sort of cova- fur atom without much change in electronegativity
lent bonding[43]. Alongthe lines of this interpreta-
tion, the result would be paradoxical in so far as one again be paradoxical in terms of hypercoordinative
would have to conclude that N P bondinginter- interaction, would then be straightforward in terms
action is stronger in the phosphine 5a (because the of steric hindrance: d(N...P) (10) < d(N...P) (11).
P distance is shorter) than in the compounds
In the non-quaternary phosphonium cation 12a,
with positively charged phosphorus.
(cf. Pauling: C 2.5, S ca. 2.2 [46]). What would
N
˚
d(N...P) = 2.70, 2.74 A and splay angles of +4.7 ,
For comparison, we investigated 1-bromo-8-di- +7.0 have been found [12], i. e. again the criteria of
benzylamino-naphthalene (DBAN-Br) as a com- steric repulsion. Since d(N...P) is more informative
pound in which the second peri substituent is than the splay angles, one might suspect that steric
rotationally symmetric. Though hypercoordinate congestion is less severe than in the DAN-P+R3
˚
bromine is known (e. g., in trihalide anions [41, 44]), salts. In the cation 12b, d(N...P) = 2.88, 2.78, 2.78 A
a N Br interaction seems unlikely, and it is, in fact, [47] is between d(N...P) in 12a and d(N...P) in 5c-f
ruled out by the large angle between the electron which is alongthe lines of our interpretation.
pair at N and the N...Br connectingline (59.6 ).
After all, we feel safe to conclude that the geome-
Not surprisingly because of the large size of Br, the try of all these compounds is governed by the steric
˚
distance d(N...Br) = 2.991 A (i. e. much shorter than situation and that N P dative bondingnowhere
˚
Σ r(vdW) = 3.45 A [45]) is even longer than in 5c-f. plays a detectable role.
Correspondingly, the splay angle, +9.4 , is larger
Experimental Section
than those found for the phosphonium salts. The
out-of-plane deformation, however, is smaller (tor-
sional angle N-C(8)...C(1)-Br 22.6 ). The grossly
analogous arrangement indicates a similar situation
in bondingand steric effects and thus supports our
conclusion concerningthe phosphonium salts.
Syntheses
Elemental analyses were performed by Mikroanaly-
tisches Labor Pascher, Remagen, Germany. The assign-
ments of the 13C NMR signals are in part tentative.
(8-Dimethylamino-naphth-1-yl)(methyl)(phenyl)phos-
phine (5, R = Me, P = P(Me)Ph). All operations were car-
ried out under argon. From 17.0 ml (103 mmol) of 1-dime-
thylamino-naphthalene, dissolved in 40 ml of anhydrous
diethylether, and 60.0 ml (96.0 mmol) of a commercial
1.6 M solution of butyl lithium in n-hexane, a suspension
of crystalline 8-dimethylamino-naphth-1-yl lithium was
prepared, as previously described [1]. At –67 to –60 C,
12.25 ml (90.3 mmol) commercial dichloro(phenyl)phos-
phine was added within 5 min. The stirred mixture was
then allowed to warm up to –35 C within 2 h and then to
+3 C within 10 min. After ca. 15 h at 0 C, a Grignard so-
lution prepared from 7.0 ml (112 mmol) of iodomethane
in 20 ml of anhydrous diethylether and 3.0 g(123 mg-
atom) of magnesium turnings was added within 40 min
so that the temperature of the mixture did not exceed
+20 C. The mixture was stirred for 18 h and then hy-
drolyzed by addition of 1 ml of ethanol and 2.7 ml of
water. The yellow solution was removed with a syringe,
the residue stirred with 30 ml of diethylether and this
ethereal extract added to the previously separated liquid.
After evaporation of the solvents, 12.75 gof a slowly
crystallizing, yellow oil were obtained which, according
to 1H NMR analysis consisted of 92% phosphine and 8%
We therefore conclude that in the DAN-P com-
pounds with four P-C bonds, a positive charge at
phosphorus is insufficient to induce the peri-nitro-
gen atom to donate its electron pair into a N-P bond.
The present X-ray data are thus in line with the con-
1
clusions which we earlier drew from H and 31P
NMR data [7].
In the (DAN)2P and (DAN)3P compounds, over-
crowdingin the peri space is even more pro-
nounced so that such compounds need not nec-
essarily show strictly analogous behaviour. How-
ever, a comparison between the phosphine 10 and
its sulfide 11 [10] is revealing. The X-ray struc-
tural data have been interpreted in favour of a weak
dative N P bondinginteraction [10] (see above).
For both compounds, they exhibit the criteria of
˚
steric repulsion (10: d(N...P) = 2.781, 2.792 A;
splay angles 1.1 , 6.5 , respectively; 11: d(N...P) =
˚
3.011, 3.009 A; splay angles 5.1 , 5.4 , respec-
tively [10]). Phosphine sulfides are deprotonated
mercapto-tri(organo)phosphonium salts [19] (i. e.
the anions of very strongacids) so that the phos-
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G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
13
1-dimethylamino-naphthalene. – 1H NMR (200 MHz, in 1.20 g( ca. 3.8 mmol) of crude (DAN)(methyl)(phenyl)-
CDCl3): 1.48, d, 2J(HP) = 6.9 Hz, 3 H (P-CH3); 2.09, phosphine and 1.50 ml (20.1 mmol) of bromoethane in
s, 3 H (N-CH3A); 2.61, s, 3 H (N-CH3B); 7.11 - 7.84, m, 3.5 ml of toluene. After 33 d, the mixture was poured into
11 H (Ar-H). – 13
C
1H NMR (50.3 MHz, in CDCl3):
40 ml of diethylether and the bromide filtered off. It liqui-
1
5
16.83, d, J(CP) = 17.0 Hz (P-CH3); 44.60, d, J(CP) = fied on the funnel and was dissolved in dichloromethane.
3.1 Hz; 47.65, d, 5J(CP) = 12.3 Hz (N(CH3A B)2; 20 sig - After evaporation of the latter, the bromide was dis-
nals between 118.54 and 144.59 ppm; 151.9, d, 3J(CP) = solved in 15 ml of water. Upon addition of 3.56 gof
3.2 Hz (C(8) of DAN). – 31P 1H NMR (81.0 MHz, in potassium iodide in 10 ml of water, the phosphonium
CDCl3): –19.08. – MS (pos. CI / isobutane): m/z = iodide precipitated as an oil. 946 mg(56%) of non-crys-
295 (M+2, 20%), 294 (M+1, 100%), 293 (M, 44%), 278 talline material was isolated by extraction of the mix-
(M-Me, 23%).
ture with dichloromethane and evaporation. Upon slow
evaporation of a solution in dichloromethane / cyclohex-
ane (3:1), 770 mg(45%) of slightly yellow crystals was
(8-Dimethylamino-naphth-1-yl)di(methyl)(phenyl)-
phosphonium iodide (5c, anion: I ). From a solution of
1.20 g( ca. 3.8 mmol) of crude (DAN)(methyl)(phenyl)-
phosphine and 0.81 ml (13.0 mmol) of iodomethane in
3.5 ml of toluene, the title compound separated within
30 min. After addition of 5 ml of toluene and 40 ml
of diethylether, 1.60 g(97%) of product was collected;
m. p. 231 - 245 C. From a solution in 80 ml of
dichloromethane to which 40 ml of cyclohexane was
added, 1.39 g(84%) crystallized duringslow evapora-
tion of the dichloromethane within 10 days; m.p. 238-
1
obtained; m. p. 208 - 211 C. – H NMR (200 MHz,
in CD2Cl2): 1.09, dt, 3J(HP) = 19.4 Hz, 3J(HH) =
7.5 Hz, 3 H (P+CH2CH3); 1.87, br s, and 2.09, br s, 3+3
H (N(CH3)2A B); 2.51, d, 2J(HP) = 12.0 Hz, 3 H (P+CH3);
2.89, ddq, 2J(HP) = 13.1 Hz, 2J(HH) = 15.0 Hz, 3J(HH) =
7.5 Hz, 1 H, and 3.11, ddq, 2J(HP) = 11.0 Hz, 2J(HH) =
15.0 Hz, 3J(HH) = 7.5 Hz, 1 H (P+CHA HB), 7.42 - 8.34,
m, 10 H (Ar-H); 8.51, ddd, 3J(HP) = 17.2 Hz, 3J(HH) =
7.4 Hz, 4J(HH) = 1.2 Hz, 1 H (C(2)-H). – 13
C
1H NMR
2
1
(50.3 MHz, in CD2Cl2): 7.17, d, J(CP) = 14.4 Hz
241 C. – H NMR (200 MHz, CD2Cl2): 2.01, s, 6 H
(P+CH2CH3); 11.99, d, 1J(CP) = 61.1 Hz (P+CH3); 21.30,
(N(CH3)2); 2.57, d, J(HP) = 12.3 Hz, 6 H (P+(CH3)2);
2
1
1
d, J(CP) = 55.9 Hz (P+CH2CH3); 111.38, d, J(CP) =
7.44 - 8.55, m (11 Ar-H). – 13
C
1H NMR (50.3 MHz,
in CDCl3): 15.79, d, J(CP) = 61.3 Hz (P+ (CH3)2);
1
91.7 Hz (Ph-C (ipso)); 121.39, s (C(7)); 123.88, d,
3
1J(CP) = 96.6 Hz (C(1)); 126.12, d, J(CP) = 15.3 Hz
1
47.34, s (N(CH3)2); 113.53, d, J(CP) = 95.2 Hz (Ph-
C(ipso)); 121.63, s (C(7)); 125.48, d, J(CP) = 98.7 Hz
1
(C(3)); 127.34, s (C(6)); 128.47, s (C(5)); 129.52, d,
3
2J(CP) = 10.4 Hz (Ph-C (ortho)); 129.93, d, J(CP) =
3
(C(1)); 126.35, d, J(CP) = 15.8 Hz (C(3)); 127.56, s
3
(C(6)); 128.65, s (C(5)); 129.32, d, 2J(CP) = 11.1 Hz (Ph-
13.2 Hz (Ph-C(meta)); 130.48, d, J(CP) = 4.5 Hz (C
(10)); 133.15, d, 4J(CP) = 3.1 Hz (C(4)); 135.92, d,
2J(CP) = 10.4 Hz (C(9)); 136.45, d, 4J(CP) = 3.6 Hz (Ph-
C(para)); 139.15, d, 2J(CP) = 10.7 Hz (C(2)); 150.18, d,
3
C(ortho)); 130.14, d, J(CP) = 13.5 Hz (Ph-C(meta));
130.45, d, 3J(CP) = 5.3 Hz (C(10)); 133.28, d, 4J(CP) =
3.1 (C(4)); 135.95, d, 2J(CP) = 8.9 Hz (C(9)); 136.64, d,
4J(CP) = 3.6 Hz (Ph-C(para)); 139.09, d, 2J(CP) = 11.8 Hz
3J(CP) = 2.4 Hz (C (8)). – 31
P
1H NMR (81.0 MHz, in
(C(2)); 150.20, s (C(8)). – 31
P
1H NMR (81.0 MHz, in
CD2Cl2): +26.74 Hz.
CDCl3): +20.13.
(8-Dimethylamino-naphth-1-yl)(ethyl)(methyl)(phe-
nyl)phosphonium tetraphenylborate (5d). Upon addition
of a solution of 244 mg(0.54 mmol) of the corresponding
phosphonium iodide in 15 ml of methanol to a solution
of 246 mg(0.72 mmol) of sodium tetraphenylborate in
10 ml of methanol, a precipitate formed which dissolved
upon addition of 25 ml of ethanol and heating. 5d crystal-
lized after addition of 10 ml of water to the hot solution;
yield 331 mg(95%); m. p. 174-176.5 C. For the X-ray
structure determination and the elemental analysis, 5c was
recrystallized from acetone / water (ca. 3:1); m. p. 175 -
(8-Dimethylamino-naphth-1-yl)di(methyl)(phenyl)-
phosphonium tetraphenylborate (5c). A solution of 467
mg(1.07 mmol) of the correspondingiodide (see before)
in 30 ml of methanol was added to a solution of 390 mg
(1.14 mmol) of sodium tetraphenylborate in 10 ml of
methanol. 5c precipitated immediately. After addition of
10 ml of water, it was filtered off; yield 651 mg(97%),
m. p. 156 - 157.5 C. For theX-ray structuredetermination
and the elemental analysis, a sample was recrystallized
1
from acetone / water (3:2); m. p. 156.5 - 157 C. – H
NMR (300 MHz, in CD2Cl2): 1.79, d, 2J(HP) = 12.0 Hz,
6 H (P+ (CH3)2); 1.91, s, 6 H (N(CH3)2); 6.80 – 8.34, m,
31 H (Ar-H). – C44H43BNP (627.6): calcd. N 2.23, P 4.93;
found N 2.28, P 4.95.
1
176 C. – H NMR (200 MHz, in CD2Cl2): 0.89, dt,
3
3J(HP) = 18.5 Hz, J(HH) = 7.5 Hz, 3H, (P+CH2CH3);
1.77, br s, and 2.03, br s, 3+3 H (N(CH3A B)2); 1.84,
2
2
d, J(HP) = 11.8 Hz, 3 H (P+CH3); 2.28, dd, J(HP) =
(8-Dimethylamino-naphth-1-yl)(ethyl)(methyl)(phe-
9.6 Hz, 3J(HH) = 7.5 Hz, 2 H (P+CH2); 6.78 - 8.32, m, 31
nyl)phosphonium iodide (5d, anion: I ). Crystals of the H (Ar-H). – C45H45BNP (641.6): calcd. N 2.18, P 4.83;
correspondingbromide separated from a solution of found N 2.27, P 4.86.
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14
G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
1-Isopropylamino-naphthalene. Upon heating100 g
138 - 141 C. Repeated recrystallization from acetone
(0.70 mol) of 1-amino-naphthalene and 80 ml (0.80 mol) / water and methanol / water raised the m. p. to 150 -
1
of 2-iodo-propane, a vigorous rection set in which was 151 C. – H NMR (300 MHz, in CDCl3): 0.93, d,
3
moderated by coolingand ceased after ca. 10 min. The 3J(HH) = 6.4 Hz, 3 H, and 1.16, d, J(HH) = 6.6 Hz,
mixture was heated with 25 ml cyclohexane. After de- 3+3 H (NCH[CH3A B]2); 1.99, s, 3 H (NCH3); 3.28, sept,
cantation of the liquid, 50 gof sodium hydroxide, 650 ml
3J(HH) = 6.5 Hz, 1 H (NCHMe2); 6.90 - 7.79, m, 16
of water, 200 ml 2N potassium hydroxide, 50 ml of H (Ar-H). – 13C 1H NMR (75.5 MHz, in CDCl3):
ethanoland 300mlof dichloromethanewereadded. Evap- 17.26, s, and 20.57, d, 6J(CP) = 9.7 Hz (NCH[CH3A B]2);
oration of the organic phase yielded 129 g of crude prod- 38.04, d, 5J(CP) = 1.8 Hz (NCHMe2); 55.84, d, 5J(CP) =
uct from which 110 g(85%) of almost colourless ma-
6.0 Hz (NCH3); 24 signals from 122.21 to 150.74. –
terial was obtained by fractional distillation; b. p. 160 - 31P 1H NMR (81.0 MHz, in CDCl3): –2.10. – MS
20
1
162 C/11 torr, nD = 1.6288. – H NMR (90 MHz, in (pos. CI/isobutane): m/z = 386 (M+3, 8%), 385 (M+2,
CDCl3): 1.25, d, 3J(HH) = 6.3 Hz, 6 H (NCH(CH3)2); 27%), 384 (M+1, 100%), 383 (M, 64%). – C26H26NP
3.73, sept, 3J(HH) = 6.3 Hz, 1 H (NCH); 4.08, br s, 1 H (383.5): calcd. N 3.65, P 8.08; found N 3.78, P 7.94.
(NH); 6.49 - 7.88, m, 7H.
[8-(Isopropyl)(methyl)amino-naphth-1-yl](methyl)di-
1-[(Isopropyl)(methyl)amino]naphthalene. 92.7
g
(phenyl)phosphonium iodide (5e, anion: I ) crystal-
(0.50 mol) 1-isopropylamino-naphthalene and 60.0 ml lized from a solution of 530 mg(1.38 mmol)
(0.63 mol) of dimethylsulfate reacted exothermally. Af- of [8-(isopropyl)(methyl)amino-naphth-1-yl]di(phenyl)-
ter 90 min and addition of 40 ml of toluene, the mixture phosphine and 1.00 ml (16.1 mmol) of iodomethane in
was heated to 130 C (bath temperature) for 90 min. Af- 14 ml of toluene; yield 699 mg(96%), m. p. 268 - 270 C,
ter cooling. 100 ml of 30% aqueous sodium hydroxide, 273 - 275 C after recrystallization from ethyl acetate /
20 ml of ethanol and 20 ml of conc. aqueous ammonia toluene (3:2). – 1H NMR (300 MHz, in CD2Cl2): 0.42,
3
3
were added. A vigorous reaction occurred. When it had d, J(HH) = 6.4 Hz, and 0.45, d, J(HH) = 6.3 Hz, 3+3
subsided, the mixture was heated to ca. 80 C for 40 min. H (NCH(CH3A B)2; 2.10, s, 3 H (NCH3); 2.93, sept, 3J =
After cooling, 600 ml of water was added. The mixture 6.5 Hz, 1 H (NCHMe2); 3.16, d, 2J(HP) = 13.3 Hz, 3 H
was extracted twice with 120 ml of n-hexane. The com- (P+CH3); 7.12 - 8.26, m, 16 H (Ar-H). – 13
C
1H NMR
1
bined organic phases were concentrated to ca. 150 ml (50.3 MHz, in CDCl3): 14.16, d, J(CP) = 64.2 Hz
and briefly heated with 40 ml of acetic anhydride, cooled (P+CH3); 17.04, s, and 19.93, s (NCH[CH3A B]2); 38.74, s
and treated with 30 gof sodium hydroxide dissolved in
(NCH3);57.31, s(NCHMe2);113.22, d, 1J(CP) =93.2Hz,
200 ml of water. After the exothermic reaction had sub- 123.58, d, 1J = 93.5 Hz and 124.27, d, 1J(CP) = 87.0 Hz
sided, the organic material was extracted into 300 ml of ((C(1), Ph-C (ipso)A B); 125.19, d, J(CP) = 16.0 Hz
3
n-hexane, recovered by evaporation and finally distilled; (C(3)); 125.35, s (C(7)); 127.53, d, 4J(CP) = 1.0 Hz
yield 74.68 gof a slightly yellow oil, b. p. 139 - 141 C/11 (C(5)); 127.63, s (C(6)); 130.13, d, 3J = 12.7, and 130.41,
torr. Chromatography on silica gel in n-pentane yielded d, 2J(CP) = 12.3 Hz (Ph-C(ortho)A B);131.67, d, 2J(CP) =
1
3
41.15 g(41%) of the title compound as an oil. – H NMR 9.9 Hz, and 132.62, d, J(CP) = 9.4 (Ph-C(meta)A B);
3
3
4
(90 MHz, in CDCl3): 1.12, d, J(HH) = 6.8 Hz, 6 H 133.18, d, J = 5.0 Hz (C(10)); 133.86, d, J = 2.9 Hz,
(NCH(CH3)2); 2.73, s, 3 H (NCH3); 3.59, sept, 3J(HH) = and 134.09, d, 4J(CP) = 2.6 Hz (Ph-C(para)A B); 135.05,
2
4
6.8 Hz, 1 H (NCHMe2); 6.99 - 8.30, m, 7 H (Ar-H).
d, J(CP) = 9.0 Hz (C(9)); 136.50, d, J (CP) = 3.7 Hz
(C(4)); 141.39, d, 2J(CP) = 12.9 Hz (C(2)); 146.39, d, 3J =
2.2 Hz (C(8)). – 31P 1H NMR (81.0 MHz, CDCl3):
+24.84.
[8-(Isopropyl)(methyl)amino-naphth-1-yl]di(phenyl)-
phosphine (5, R = CHMe2, P = PPh2). The reaction was
performed in an argon atmosphere. 20.0 ml (32.0 mmol)
of a commercial 1.6 M solution of n-butyl lithium in n-
hexane was added to a solution of 6.30 g(31.6 mmol) of
[8-(Isopropyl)(methyl)amino-naphth-1-yl](methyl)di-
(phenyl)phosphonium tetraphenylborate (5e) precipitated
1-(isopropyl)(methyl)amino-naphthalene in 8 ml of an- from a solution of 315 mg(0.60 mmol) of the correspond-
hydrous diethylether. During39 d at ca. 25 - 30 C, a ingiodide in 20 ml of methanol upon addition of a solution
yellow product crystallized. After 10 more days, the red of 252 mg(0.74 mmol) of sodium tetraphenylborate in
liquid was removed with a syringe, the crystals washed 10 ml of methanol. 30 ml of water was added to complete
with 5 ml of anhydrous diethylether and suspended in the precipitation; yield 405 mg(94%), m. p. 205 - 208 C.
10 ml of diethylether. 1.80 ml (10.0 mmol) of chloro- For the X-ray structure determination and the elemental
diphenylphosphine was added and the mixture kept at analysis, a sample was recrystallized from ethyl acetate /
room temperature for 20 h. Conventional workup yielded acetone (3:1); m. p. 208 - 210 C. – 1H NMR (200 MHz,
3
3.21 gcrude phosphine, 2.24 g(58%) after recrystal-
in CD2Cl2): 0.38, d, J(HH) = 6.5 Hz, and 0.39, d,
lization from acetone/water (10:1), yellow crystals, m. p. 3J(HH) = 6.4 Hz, 3+3 H (NCH(CH3A B)2); 2.07, s 3 H
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G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
(NCH3); 2.66, d, 2J(HP) = 13.3 Hz, 3 H (P+CH3); 2.82,
15
The structures were solved by direct methods [49] and
sept, 3J(HH) = 6.5 Hz, 1 H (NCHMe2); 6.79-8.24, m, 36 refined usingSHELXL [50]. The refinement was based
2
2
H (Ar-H). – C51H49BNP (717.7): calcd. N 1.95, P 4.31; on
for all reflections except those with negative
.
found N 2.17, P 4.39.
Weighted factors
and all goodness-of-fit S values
are based on 2. Conventional R factors are based on
(8-Dimethylamino-naphth-1-yl)(ethyl)di(phenyl)-
phosphonium tetraphenylborate (5f). The synthesis has
been described in [7].
2
2
with set to zero for negative 2. The
> 2s(
)
o
o
criterion was used only for calculating factors and is
not relevant to the choice of reflections for the refine-
ment. The factors based on 2 are about twice as large
as those based on . All hydrogen atoms were located
from a differential map and refined isotropically. Scatter-
ingfactors were taken from Tables 6.1.1.4 and 4.2.4.2 in
Ref. [51].
1-Bromo-8-dibenzylamino-naphthalene (DBAN-Br).
A mixture of 11.18 g(50.3 mmol) of 1-amino-8-bromo-
naphthalene (m. p. 87 - 88.5 C) [48], 18.0 ml (151 mmol)
of benzyl bromide, 12.36 g(89 mmol) of potassium car-
bonate and 80 ml of diglyme was refluxed 3 h in an atmo-
sphere of argon, then cooled down to ca. 100 C, diluted
with 100 ml of water, kept at ca. 100 C for 30 min and at
RT for ca. 15 h. 250 ml of toluene was added, the organic
layer washed with water and filtered through a multi-layer
column consistingof sodium sulfate, silica gel, sodium
sulfate, basic aluminium oxide and again sodium sulfate.
Evaporation of the toluene yielded 23.8 gof a reddish
brown oil. This was dissolved in 300 ml of hot ethanol
and the solution boiled with charcoal. After cooling, the
title compound crystallized slowly; yield 11.88 gof bright
yellow crystals, m. p. 106 - 108 C. A second crop (2.98 g,
m. p. 104 - 107 C) crystallized from the filtrate after
addition of 30 ml of water; total yield 73%. For the X-
ray structure determination and the elemental analysis, a
sample was recrystallized first from cyclohexane / n-pen-
tane (1:1) and then from ethanol; yellow needles, m. p.
109-111 C. – 1H NMR (200 MHz, in CDCl3): 4.19, d,
2J(HH) = 14.3 Hz, 2 H (N(CHAHBPh)2); 4.29, d, 2J(HH) =
14.2 Hz (N(HAHBPh)2); 6.74-7.88, m, 16 H. – 13C NMR
(50.3 MHz), in CDCl3): 57.88, t (N(CH2Ph)2); 118.13,
s; 120.50, d; 123.56, d; 125.61, d; 125.74, d; 126.35,
s; 126.96, d; 127.88, d; 129.03, d, 133.33, d, 136.75,
s; 137.61, s; 146.68, s. – MS (EI, 70 eV): m/z = 404
(13C/81Br-M, 15%), 403 (81Br-M, 57%), 402 (13C/79Br-
M, 17%), 401 (79Br-M, 54%), 322 (16%), 312 (81Br-M –
C7H7, 29%), 310 (79Br-M – C7H7), 230 (79%), 91 (C7H7,
100%). – C24H20BrN (402.3): calcd. Br 19.86, N 3.48;
found Br 19.8, N 3.55.
Crystal data
5c: C44H43B1N1P1, M = 627.57, colourless, mono-
clinic, P21/c, Z = 4, a = 14.659(3), b = 9.0464(18), c =
3
˚
˚
26.558(5) A, = 92.27(3) , V = 3519.1(12) A , Dc =
1.185 mg/mm3, = 0.110 mm 1, F(000) = 1336. A to-
tal of 66418 reflections, 8694 unique [Rint = 0.0465] at
295.0 K, final wR2 = 0.1072, R1 = 0.0436 (reflections
with I > 2 (I)) and goodness-of-fit = 0.806 for 597 re-
fined parameters.
5d: C45H45B1N1P1, M = 641.60, colourless, mono-
clinic, P21/n, Z = 4, a = 13.105(3), b = 18.045(4), c =
3
˚
˚
15.245(3) A, = 96.73(3) , V = 3580.2(12) A , Dc =
1.190 mg/mm3, = 0.110 mm 1, F(000) = 1368. A to-
tal of 24037 reflections, 8670 unique [Rint = 0.0428] at
295.0 K, final wR2 = 0.0962, R1 = 0.0442 (reflections
with I > 2 (I)) and goodness-of-fit = 0.835 for 614 re-
fined parameters.
5e: C51H49B1N1P1, M = 717.69, colourless, mono-
clinic, P21/n, Z = 4, a = 11.818(2), b = 19.966(4), c =
3
˚
˚
17.205(3) A, = 94.87(3) , V = 4045.0(14) A , Dc =
1.178 mg/mm3, = 0.104 mm 1, F(000) = 1528. A total
of 80088 reflections, 10410 unique reflections, analytical
absorption correction applied, [Rint = 0.055] at 295.0K, fi-
nal wR2 = 0.1932, R1 = 0.0682 (reflections with I > 2 (I))
and goodness-of-fit = 1.010 for 684 refined parameters.
5f: C50H47B1N1P1, M = 703.66, colourless, triclinic,
X-ray diffraction
¯
˚
P1, Z = 4, a = 12.040(2), b = 15.020(3), c = 23.210(5) A,
= 98.46(3), = 98.36(3) , = 104.10(3), V =
All measurements of diffractional data were per-
formed on a Kuma KM4CCD -axis diffractometer with
graphite-monochromated Mo-K radiation. The crystals
were positioned at 65 mm from the KM4CCD camera.
612 (for 5c and 5e) and 2120 (for the other crystals) frames
were measured at 0.6 - 0.8 intervals with a countingtime
of 6 - 45 sec. The data were corrected for Lorentz and po-
3
3
1
˚
3954(1) A , Dc = 1.182 mg/mm ,
= 0.105 mm ,
F(000) = 1496. A total of 38052 reflections, 7371 unique
[Rint = 0.1177] at 295.0 K, final wR2 = 0.1225, R1 = 0.1119
(reflections with I > 2 (I)) and goodness-of-fit = 1.278
for 994 refined parameters.
DBAN-Br: C24H20Br1N1, M = 402.32, yellow crystal,
larization effects. No absorption correction was applied orthorhombic, Pca21, Z = 4, a = 15.136(3), b = 13.033(3),
3
3
˚
˚
with exception of 5e. Data reduction and analysis were c = 9.4559(19) A, V = 1865.4(6) A , Dc = 1.433 mg/mm ,
carried out with the Kuma Diffraction (Wroclaw, Poland)
suite of programs.
= 2.210 mm 1, F(000) = 824. A total of 11865 reflec-
tions, 3127 unique [Rint = 0.0949] at 295.0 K, final wR2 =
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16
G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
0.1248, R1 = 0.0517 (reflections with I > 2 (I)) and good- application to CCDC, 12 Union Road, Cambridge CB2
ness-of-fit = 1.053 for 316 refined parameters. 1EW, UK (Fax: Int code + (1223)336-033; E-mail:
Crystallographic data (excluding structural factors) for deposit@ccdc.cam.ac.uk).
the structures reported in this paper have been deposited
with the Cambridge Crystallographic Data Centre and al-
Acknowledgements
located the deposition numbers: CCDC 150873, CCDC
150874. CCDC 150875, CCDC 150876 and CCDC
150877 for 5c, 5d, 5e, 5f and DBAN-Br, respectively.
Financial support by the Volkswagen Foundation
(Hannover) (project Experimental and theoretical con-
formational analysis of organic compounds in solution)
Copies of the data can be obtained free of charge on is gratefully acknowledged.
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17
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1946 (1997); Angew. Chem. Int. Ed. Engl. 36, 1884
(1997)).
[27] H. W. W. Ehrlich, Acta Crystallogr. 10, 699, (1957)
˚
[21] G. P. Schiemenz, B. Schiemenz, S. Petersen,
C. Wolff, Chirality 10, 180 (1998).
(acenaphthene, d(H2C-CH2) = 1.54 A).
[28] T. C. W. Mak, J. Trotter, Acta Crystallogr. 16,
[22] E. g., in 1,8-dimethyl-naphthalene: D. Bright, I. E.
Maxwell, J. de Boer, J. Chem. Soc., Perkin Trans.
2, 1973, 2101.
[23] E. g., in 1,8-diphenyl-naphthalene: R. L. Clough,
W. J. Kung, R. E. Marsh, J. D. Roberts, J. Org.
Chem. 41, 3603 (1976).
811 (1963) (acenaphthenequinone, d(OC-CO) =
˚
1.53 A).
[29] R. A. Wood, T. R. Welberry, A. D. Rae, J. Chem.
Soc., Perkin Trans 2 1985, 451 (acenaphthylene,
˚
d(HC=CH) = 1.40 A).
[30] C. W. Holzapfel, M. W. Bredenkamp, R. M. Sny-
man, J. C. A. Boeyens, C. C. Allen, Phytochem-
istry 29, 639 (1990); A. Wang, H. Zhang, E. Biehl,
Heterocycles 48, 303 (1998) (2 substituted naph-
[24] E. g., in 1,8-dimethoxy-naphthalene: L. J. Fitz-
gerald, J. C. Gallucci, R. E. Gerkin, Acta Crystal-
logr. B 47, 776 (1991).
˚
˚
thostyrils, d(N-CO) = 1.37 and 1.38 A).
[25] E. g., 2.584 A in 1,8-F2C10H6 (A. Meresse, C. Cour-
seille, F. Leroy, N. B. Chanh, Acta Crystallogr. B 31, [31] C. J. McAdam, J. J. Brunton, B. H. Robinson,
˚
1236 (1975)), 2.545 A in 1,8-(MeO)2C10H6 [24],
J. Simpson, J. Chem. Soc., Dalton Trans. 1999,
˚
2.793 A in 1,8-(Me2N)2C10H6 (K. Wozniak, H. He,
J. Klinowski, B. Nogaj, D. Lemanski, D. E. Hibbs,
2487 (a ferrocenyl-substituted bis(methylene)ace-
˚
naphthene, d((C=)C-C(=C)) = 1.51 A).
M. B. Hursthouse, S. T. Howard, J. Chem. Soc., [32] Molecule A of two independent molecules in the
Faraday Trans. 91, 3925 (1995). Note that these dis-
tances are shorter than the respective Σ r(vdW) (F/F
unit cell [11]; splay angle calculated from the atomic
˚
coordinates [11]; molecule B: d(N...P) = 2.729 A.
˚
˚
˚
3.0 A, O/O 3.2 A, N/N 3.1 A [45]) by 14%, 20% and [33] Cf. A. Schmidpeter, T. von Criegern, K. Blanck,
10%, respectively. Accordingto the procedure of
R. O. Day, T. K. Prakasha, R. R. Holmes, H. Eckert,
Organometallics 13, 1285 (1994) (p. 1290), and
T K. Prakasha, S. Srinivasan, A. Chandrasekaran,
R. O. Day, R. R. Holmes, J. Am. Chem. Soc. 117,
Z. Naturforsch. 32b, 1058 (1976). A cornucopia of
examples is listed in pertinent reviews such as R. R.
Holmes, Pentacoordinated Phosphorus, I, II, (ACS
Monograph 175, 176), American Chemical Society,
Washington, D.C. (1980).
10003 (1995) (p. 10006) (which has been applied [34] R. R. Holmes, Acc. Chem. Res. 31, 535 (1998).
to DAN-P compounds [16]), they would stand for [35] G. Wittig, M. Rieber, Liebigs Ann. Chem. 562, 187
a hypercoordinate character of 14.2% (F), 34.8%
(1949).
(O) and 18.1% (N) (calculations based on the cova- [36] D. Hellwinkel, Chem. Ber. 98, 576 (1965).
lent radii of L. Pauling, The Nature of the Chemical [37] Note that even in cases of strongest steric hindrance,
Bond and the Structure of Molecules and Crystals,
2nd ed., p. 164, Cornell U. P., Ithaca NY (1945).
the geometry of the naphthalene skeleton does not
permit the peri substituents to attain Σ r(vdW) dis-
tances and that it is therefore a matter of course that
they reside at sub-van-der-Waals distances.
[26] A recently published DAN-silacyclobutane struc-
˚
ture (d(N...Si) = 2.61, 2.62 A) revealed a very
small in-plane and a considerable out-of-plane dis- [38] W. Klyne, V. Prelog, Experientia 16, 521 (1960);
tortion: M. Spiniello, J. M. White, Organometallics
19, 1350 (2000). Not surprisingly, 1,4,5,8-tetrasub-
cf. S. Kane, W. H. Hersh, J. Chem. Educ. 77, 1366
(2000).
stituted naphthalenes have considerable recourse to [39] With reference to unpublished X-ray data contained
out-of-plane distortion, because an increase of the
interatomic distances by in-plane distortion in the
1,8-peri space is always combined with a compres-
sion of the 4,5-peri space and is thus opposed by
4,5-substituents: e. g. 1,4,5,8-Cl4C10H4 (G. Gafner,
F. H. Herbstein, Acta Crystallogr. 15, 1081 (1962));
1,4,5,8-Ph4C10H4 (G. Evrard, P. Piret, M. Van
Meerssche, Acta Crystallogr. 28, 497 (1972)); 1,8-
(Me2N)2-4,5-(CHO)2C10H4 (A. F. Pozharskii, G. G.
Aleksandrov, N. V. Vistorobskii, Zh. Org. Khim.
27, 1536 (1991); J. Org. Chem. (USSR) 27, 1347
(1991); considerable out-of-plane distortion in addi-
tion to strongin-plane distortion on both peri sides;
splay angles +7.7 on the (Me2N)2 side, +9.4 on
the formyl side); C10Ph8 (X. Qiao, M. A. Padula,
D. M. Ho, N. J. Vog elaar, C. E. Schutt, R. A.
Pascal (Jr.), J. Am. Chem. Soc. 118, 741 (1996));
1,8-(Me2N)2-4,5-(MeO)2C10H4 (H. A. Staab, C.
in a Ph. D. thesis, it has been claimed that in DAN-
P+ (CH2Ph)Ph2 Br [7], the lone pair of the nitrogen
atom is directed towards the phosphorus atom trans
to the benzyl group [13]. Since no numerical values
˚
other than d(N...P) = 2.83 A are given, it cannot
be judged whether this salt indeed behaves differ-
˚
2.50 A
ent from 5c-f. In our opinion, d(N...P)
and the tetrahedral geometry around P+ (certainly
somewhat distorted because of different substituents
at P+) with the Me2N group “capping” one of the
tetrahedral planes as a geometric necessity [19, 20]
are evidence against N P dative interaction. The
topomerization barriers of the Me groups at N in
5a, its chalkogenides and its ethoxycarbonylmethyl
phosphonium cation observed in dynamic 1H NMR
spectroscopy [13] can be ascribed to sterically hin-
dered rotation [14, 21] and thus do not show “that all
+
these compounds [includingDAN-P (CH2Ph)Ph2-
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18
G. P. Schiemenz et al. · peri-Interactions in Naphthalenes, 6
Br ] are pseudopentacoordinated or pentacoordi- [44] R. Caminiti, M. Carbone, G. Mancini, C. Sadun,
nated in solution... in agreement with the solid-state
structures”.
J. Mater. Chem. 7, 1331 (1997); R. Minkwitz,
R. Bro¨chler, R. Ludwig, Inorg. Chem. 36, 4280
(1997); J. Hu¨bner, D. Wulff-Molder, H. Vogt,
M. Meisel, Z. Naturforsch. 52b, 1321 (1997).
[40] Cf., e.g., “three weak N P interactions” [10],
“N P dative bonds”, “a six-coordinate phosphorus
center with an intramolecular N P donor-accep- [45] S. S. Batsanov, Izvest. Akad. Nauk, Ser. Khim. 1995,
tor interaction” (F. Carre´, C. Chuit, R. J. P. Cor-
24-29; Russian Chem. Bull. 44, 18 (1995).
riu, A. Mehdi, C. Reye´, Inorg. Chim. Acta 250, 21 [46] L. Pauling[25], pp. 64, 66. Cf. M. A. Brook,
(1996)).
Silicon in Organic, Organometallic, and Poly-
mer Chemistry, p. 35, John Wiley & Sons, New
York, Chichester, Weinheim, Brisbane, Singapore,
Toronto (2000). Our reasoningis based on the for-
mula R3P+-S of phosphine sulfides; it is blurred by
the formula R3P=S which, though presently fashion-
able, is in our opinion rather inappropriate.
[41] For useful definitions of donor-acceptor (or da-
tive) bonds, stressingthe similarities between do-
nor-acceptor interactions and hypervalent bonding,
see G. A. Landrum, N. Goldberg, R. Hoffmann,
J. Chem. Soc., Dalton Trans. 1997, 3605.
[42] Cf. K. Niedenzu, J. W. Dawson, Boron-Nitrogen
Compounds [Anorg. u. allg. Chemie in Einzel- [47] A. Chandrasekaran, N. V. Timosheva, R. O. Day,
darstellungen], Chapter I/A: The Boron-Nitrogen
Dative Bond, pp. 8-12, Springer Verlag, Berlin, Hei-
delberg, New York (1965).
R. R. Holmes, Inorg. Chem. 39, 1338 (2000). Cf.
C. Chuit, R. J. P. Corriu, P. Monforte, C. Reye´, J.-P.
Declercq, A. Dubourg[8].
[43] Note that even in the absence of geometry-im- [48] L. F. Fieser, A. M. Seligman, J. Am. Chem. Soc. 61,
+
posed restrictions, in the salts PI4 GaI4 and
136 (1939).
+
PI4 AlBr4 , the Coulomb attraction between the [49] G. M. Sheldrick, Acta Crystallogr. A 46, 467 (1990).
cation and the anion suffices to bringabout halo-
gen(cation)...halogen(anion) distances shorter than
[50] G. M. Sheldrick, SHELXL93. Program for the Re-
finement of Crystal Structures, Univ. of Go¨ttingen,
Germany.
˚
Σ r(vdW) by ca. 0.9 and 0.7 A, respectively:
C. Aubauer, M. Kaupp, T. M. Klapo¨tke, H. No¨th, [51] A. J. C. Wilson (ed.), International Tables for Crys-
H. Piotrowski, W. Schnick, J. Senker, M. Suter,
J. Chem. Soc., Dalton Trans. 2001, 1880.
tallography, Vol. C., Kluwer, Dordrecht (1992).
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