Di-tert-butyl ketone hydrazone and di-tert-butyl ketone triphenyl-phosphoranylidenehydrazone

Article abstract of DOI:10.1107/S0108270106008687

Reaction of di-tert-butyl ketone with hydrazine hydrate gives di-tert-butyl ketone hydrazone, C₉H₂₀N₂, which is dimerized by double hydrogen bonding in the solid state. Further reaction of this compound with dibromotriphenylphosphorane gives di-tert-butyl ketone triphenylphosphoranylidene-hydrazone, C₂₇H₃₃N ₂P, in the structure of which double chains parallel to the c axis are formed through weak C - H ... n and π-π stacking interactions. The hydrazone group is nearly planar in both cases. In the second compound, one of the aromatic rings is nearly coplanar with the hydrazone moiety, indicating possible π-conjugation.

Full text of DOI:10.1107/S0108270106008687

organic compounds
Acta Crystallographica Section C
Crystal Structure
has been reported previously (Bethell et al., 1992). Compound
(II) could not be transformed into tetra-tert-butylethylene.
Communications
The asymmetric unit in (I) contains one hydrazone mol-
ecule. The C1 N2 and N1ÐN2 bond lengths (Table 1) are in
agreement with the mean values reported for similar hydra-
ISSN 0108-2701
zones in the Cambridge Structural Database (CSD, Version
Ê
Di-tert-butyl ketone hydrazone and
di-tert-butyl ketone triphenyl-
phosphoranylidenehydrazone
5
.27; Allen, 2002), which are 1.282 (11) and 1.38 (3) A,
respectively. The C1ÐC2 and C1ÐC6 bond lengths and the
C2ÐC1ÐC6 angle are also in agreement with the mean values
2
for similar di-tert-butyl-substituted sp -hybridized C atoms
Ê
reported in the CSD, which are 1.56 (5) A and 123 (3) . The
ꢀ
ꢀ
Claude Villiers, Pierre Thu e ry* and Michel Ephritikhine
value of the N2ÐC1ÐC6 angle is lower by about 11 than
those of the other two angles around C1, which is likely due to
the minimal crowding in the corresponding sector, atom N1
being on the same side as C2. The ®ve atoms N1, N2, C1, C2
CEA/Saclay, DSM/DRECAM/SCM (CNRS URA 331), B aà timent 125, 91191 Gif-sur-
Yvette, France
Correspondence e-mail: pierre.thuery@cea.fr
Ê
and C6 de®ne a plane with an r.m.s. deviation of 0.005 A.
Received 10 February 2006
Accepted 8 March 2006
Online 31 March 2006
Centrosymmetric dimers are formed through double
hydrogen bonding between the NÐNH2 groups of two
neighbouring molecules, with the formation of a six-
membered ring (Fig. 1 and Table 2).
The asymmetric unit in (II) contains two independent but
nearly identical molecules, denoted A and B (molecule A is
represented in Fig. 2). These two molecules ®t to one another
Reaction of di-tert-butyl ketone with hydrazine hydrate gives
di-tert-butyl ketone hydrazone, C H N , which is dimerized
9
20
2
by double hydrogen bonding in the solid state. Further
reaction of this compound with dibromotriphenylphospho-
rane gives di-tert-butyl ketone triphenylphosphoranylidene-
hydrazone, C H N P, in the structure of which double chains
Ê
with an overall r.m.s. deviation of 0.143 A (the largest devia-
Ê
tions, up to 0.29 A, are those of atoms in the tert-butyl groups
and aromatic rings) (OFIT in SHELXTL; Bruker, 1999). The
Ê
C1 N2 bond lengths [Table 3; mean value 1.2905 (15) A], as
well as the angles around C1, match those in (I), but the N1Ð
Ê
N2 distances [mean value 1.4205 (5) A] are slightly larger than
Ê
those in compounds (I) and (III) [1.388 (4) A] and are also
2
7
33
2
parallel to the c axis are formed through weak CÐHÁ Á Áꢀ and
ꢀ±ꢀ stacking interactions. The hydrazone group is nearly
planar in both cases. In the second compound, one of the
aromatic rings is nearly coplanar with the hydrazone moiety,
indicating possible ꢀ-conjugation.
larger than the mean value for NÐN bond lengths in
triphenylphosphoranylidene
hydrazone
C H ) groups reported in the CSD [1.384 (19) A]. This may
C
NÐN P-
Comment
Ê
(
be due to the crowding induced by the simultaneous presence
6
5 3
To date, the highly sterically crowded alkene tetra-tert-butyl-
ethylene has not been synthesized, in spite of many attempts
using various methods, such as the McMurry coupling reaction
of tert-butyl groups and aromatic rings in (II). However, the
Ê
mean P1 N1 bond length of 1.6017 (9) A is slightly shorter
(
(
Ephritikhine & Villiers, 2004), Barton's extrusion process
Barton et al., 1974) and reactions exploiting other possible
Ê
than the mean value of 1.616 (13) A from the CSD and the
Ê
value of 1.606 (3) A in (III). These bond lengths indicate the
pathways (Sulzbach et al., 1996). During our investigations
into the McMurry reaction, we have particularly studied the
carbonyl coupling of benzophenone and di-tert-butyl ketone
presence of double bonds between C1 and N2 and between P1
and N1. However, their slight deviation from the values
tabulated for single and double bonds has been considered as
0
0
with the MCl /M (Hg) system (M/M = U/Na, U/Li or Ti/Li)
4
(Ephritikhine & Villiers, 2004). During this work, we have
prepared di-tert-butyl ketone hydrazone, (I), and the new
compound di-tert-butyl ketone triphenylphosphoranylidene
hydrazone, (II), by analogy with the synthesis reported for the
two corresponding benzophenone derivatives (Barton et al.,
1974; Bestmann & Fritzsche, 1961). The crystal structure of
benzophenone triphenylphosphoranylidenehydrazone, (III),
Figure 1
A view of (I), showing the atom-numbering scheme. Hydrogen bonds are
shown as dashed lines. Displacement ellipsoids are drawn at the 50%
probability level. Primed atoms are related by the symmetry operator
(� x, � y, � z).
o234 # 2006 International Union of Crystallography
DOI: 10.1107/S0108270106008687
Acta Cryst. (2006). C62, o234±o236

organic compounds
possible evidence of ꢀ-conjugation over the whole of the
triphenylphosphoranylidene hydrazone moiety (Bethell et al.,
respectively (but with, however, out-of-plane displacements as
Ê
large as 0.4 A). Such a geometry has previously been observed
1992). This moiety adopts a trans geometry with respect to the
central N1ÐN2 bond in (II), as is usual in such compounds
in a related triphenylphosphoranylidene hydrazone com-
(2,4-cyclopentadien-1-ylidenehydrazono)triphenyl-
pound,
(
Bethell et al., 1992; Minutolo et al., 1999).
The group de®ned by atoms P1, N1, N2, C1, C2 and C6 is
close to planarity in both molecules of (II), with r.m.s. devia-
phosphorane, (IV), and considered as indicative of the
possibility of ꢀ-conjugation between the two fragments, which
was supported by the corresponding PÐC bond length being
Ê
tions of 0.010 and 0.024 A and P1ÐN1ÐN2ÐC1 torsion
angles of 179.55 (14) and 175.93 (14) in molecules A and B,
respectively. One of the aromatic rings in both molecules
Ê
slightly smaller than those of the other two, by about 0.011 A
(Minutolo et al., 1999). The P1ÐC10 bonds in (II) are also
slightly shorter than P1ÐC16 and P1ÐC22, by about 0.01±
ꢀ
Ê
0.02 A, which con®rms the previous observation. However,
the CÐN, NÐN, PÐN and PÐC bonds in (II) are all longer,
Ê
by 0.01±0.05 A, than their counterparts in (IV) (the largest
(
phosphoranylidene hydrazone mean plane, with dihedral
angles of 8.70 (12) and 2.78 (12) in molecules A and B,
atoms C10±C15) is nearly coplanar with the triphenyl-
ꢀ
difference corresponds to NÐN), which may partly be due to
the data collection temperature difference of 98 K, but also to
the presence in (IV) of a Cp ring instead of the two tert-butyl
groups in (II), with possible additional conjugation effects.
The aromatic CÐC bond lengths in (II) are in the usual range
in all three rings.
The aromatic rings in (II) are involved in several weak
intermolecular interactions. ꢀ±ꢀ stacking interactions are
possibly present between rings C10±C15 (centroid Cg1) and
C16±C21 (centroid Cg2) of molecules related by a glide plane
i
Ê
for both A and B molecules [Cg1AÁ Á ÁCg2A = 3.76 A, dihedral
ꢀ
Ê
angle = 7.0 , centroid offset = 1.65 A and shortest interatomic
i
Ê
Ê
contact = 3.26 A for A molecules; Cg1BÁ Á ÁCg2B = 3.64 A,
ꢀ
Ê
dihedral angle = 6.5 , centroid offset = 1.22 A and shortest
Ê
interatomic contact = 3.36 A for B molecules; symmetry code:
3
2
1
2
(
i) x, � y, z � ]. Although the shortest interatomic contacts
are shorter than twice the out-of-plane van der Waals radius of
Ê
C (1.7 A; Bondi, 1964), these interactions are weak at best,
Figure 2
A view of molecule A in (II), showing the atom-numbering scheme.
Displacement ellipsoids are drawn at the 50% probability level.
due to the large offset values.
Three signi®cant CÐHÁ Á Áꢀ interactions are also present.
One of them links molecules A and B in the asymmetric unit
ꢀ
Ê
(
H13AÁ Á ÁCg1B = 2.74 A and C13AÐH13AÁ Á ÁCg1B = 153 )
and the other two involve two sets of adjacent A or B mol-
Ê
ii
ecules [H20AÁ Á ÁCg3A = 2.68 A and C20AÐH20AÁ Á Á
ii
ꢀ
ii
Ê
Cg3A = 154 ; H20BÁ Á ÁCg3B = 2.60 A and C20BÐH20BÁ Á Á
ii
Cg3B = 147 ; Cg3 is the centroid of the C22±C27 ring;
ꢀ
3
1
symmetry code: (ii) x, � y, z + ]. Molecule A thus acts as a
2
2
hydrogen-bond donor to two neighbouring molecules and as
an acceptor from one, whereas molecule B acts as a single
donor and double acceptor. These interactions result in
double chains of A and B molecules running along the c axis
(Fig. 3).
Experimental
Reaction of di-tert-butyl ketone (5.70 g, 0.04 mol) with hydrazine
hydrate (6 ml, 0.12 mol) in diethylene glycol (14 ml) gave compound
1
I) (5.90 g) in 94% yield. The H NMR spectrum of (I) in CDCl
(
3
is
identical to that described previously (Hartzler, 1971). Reaction of
I) (1.56 g, 0.01 mol) with dibromotriphenylphosphorane (4.22 g,
(
1
.01 mol) gave compound (II) (2.50 g) in 60% yield. H NMR
0
Figure 3
t
t
(
(
200 MHz, CDCl
m, 9H, ortho- and para-Ph
3
): ꢁ 1.08 (s, 9H, Bu), 1.56 (s, 9H, Bu), 7.33±7.51
P), 7.61±7.74 (m, 6H, meta-Ph P). Single
A view of (II), showing the double chains along the c axis. CÐHÁ Á Áꢀ and
3
3
ꢀ
±ꢀ stacking interactions are represented by dashed and dotted lines,
respectively. Displacement ellipsoids are drawn at the 30% probability
level.
crystals of both compounds were obtained by slow evaporation of
pentane solutions.
ꢁ
Acta Cryst. (2006). C62, o234±o236
Villiers et al.
9
C H
N
20 2
and C27H
33
2
N P
o235

organic compounds
Compound (I)
Re®nement
2
2
2
2
Re®nement on F
2
o
w = 1/[ꢆ (F ) + (0.0646P)
Crystal data
2
R[F > 2ꢆ(F )] = 0.044
wR(F ) = 0.118
+ 1.2906P]
where P = (F
�
3
2
2
o
2
c
C
9
H N
20 2
D
x
= 1.040 Mg m
+ 2F
)/3
M
r
= 156.27
Mo Kꢃ radiation
S = 0.99
9059 re¯ections
553 parameters
H-atom parameters constrained
(Á/ꢆ)max = 0.001
Ê
� 3
Monoclinic, P2 =c
Cell parameters from 23020
re¯ections
Áꢇmax = 0.18 e A
1
Áꢇmin = � 0.31 e AÊ �
3
Ê
a = 11.5299 (8) A
Ê
b = 8.0975 (4) A
ꢀ
ꢄ = 3.1±25.7
Ê
c = 10.8937 (8) A
� 1
ꢅ = 0.06 mm
T = 100 (2) K
ꢀ
ꢂ = 101.111 (3)
V = 998.01 (11) A
Z = 4
Table 3
Selected geometric parameters (A, ) for (II).
Ê
3
Irregular, colourless
0.23 Â 0.19 Â 0.16 mm
Ê
ꢀ
P1AÐN1A
P1AÐC10A
P1AÐC16A
P1AÐC22A
N1AÐN2A
C1AÐN2A
C1AÐC2A
C1AÐC6A
1.6025 (16)
1.8030 (18)
1.811 (2)
1.8214 (19)
1.421 (2)
1.292 (2)
1.552 (3)
1.548 (3)
P1BÐN1B
P1BÐC10B
P1BÐC16B
P1BÐC22B
N1BÐN2B
C1BÐN2B
C1BÐC2B
C1BÐC6B
1.6008 (16)
Data collection
1.8006 (18)
1.8114 (19)
1.8212 (19)
1.420 (2)
1.289 (2)
1.555 (3)
1.552 (3)
Nonius KappaCCD area-detector
diffractometer
Rint = 0.038
ꢀ
ꢄ
max = 25.7
'
and ! scans
h = � 14 ! 13
k = � 9 ! 0
l = 0 ! 13
2
1
1
3020 measured re¯ections
884 independent re¯ections
717 re¯ections with I > 2ꢆ(I)
Re®nement
P1AÐN1AÐN2A
N1AÐN2AÐC1A
N2AÐC1AÐC2A
N2AÐC1AÐC6A
C2AÐC1AÐC6A
109.19 (12)
119.47 (16)
123.44 (17)
112.72 (17)
123.80 (16)
P1BÐN1BÐN2B
N1BÐN2BÐC1B
N2BÐC1BÐC2B
N2BÐC1BÐC6B
C2BÐC1BÐC6B
109.58 (12)
119.41 (16)
123.49 (17)
112.55 (17)
123.95 (16)
2
2
2
2
Re®nement on F
2
o
w = 1/[ꢆ (F ) + (0.0544P)
2
R[F > 2ꢆ(F )] = 0.039
wR(F ) = 0.105
S = 1.03
+ 0.3197P]
where P = (F
(Á/ꢆ)max < 0.001
Áꢇmax = 0.27 e A
Áꢇmin = � 0.15 e AÊ
2
2
2
c
o
+ 2F
)/3
Ê
� 3
1
1
884 re¯ections
12 parameters
� 3
H atoms: see below
The two H atoms bound to N1 in (I) were found in a difference
Fourier map and they were re®ned with Uiso(H) = 1.2Ueq(N1). All
other H atoms in both compounds were introduced at calculated
Table 1
Selected geometric parameters (A, ) for (I).
Ê
ꢀ
positions as riding atoms, with CÐH bond lengths of 0.93 (aromatic
Ê
3 3
CH) or 0.96 A (CH ), and with Uiso(H) = 1.2Ueq(CH) or 1.5Ueq(CH ).
N1ÐN2
C1ÐN2
1.3992 (13)
1.2864 (14)
C1ÐC2
C1ÐC6
1.5585 (14)
1.5504 (15)
For both compounds, data collection: COLLECT (Nonius, 1998);
cell re®nement: HKL2000 (Otwinowski & Minor, 1997); data
reduction: HKL2000; program(s) used to solve structure: SHELXS97
N1ÐN2ÐC1
N2ÐC1ÐC2
123.28 (9)
123.39 (9)
N2ÐC1ÐC6
C2ÐC1ÐC6
112.76 (9)
123.83 (9)
(
(
Sheldrick, 1997); program(s) used to re®ne structure: SHELXL97
Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1999);
software used to prepare material for publication: SHELXTL and
PLATON (Spek, 2003).
Table 2
Hydrogen-bond geometry (A, ) for (I).
Ê
ꢀ
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: HJ3003). Services for accessing these data are
described at the back of the journal.
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
3.0937 (13)
DÐHÁ Á ÁA
i
N1ÐH1Á Á ÁN2
0.930 (15)
2.230 (15)
154.1 (12)
Symmetry code: (i) � x; � y; � z.
References
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Crystal data
�
3
C
27
33
H N
2
P
D
x
= 1.160 Mg m
r
M = 416.52
Monoclinic, P2 =c
Ê
a = 29.1768 (16) A
b = 11.6848 (7) A
Ê
c = 14.3768 (6) A
ꢂ = 103.243 (3)
V = 4771.1 (4) A
Z = 8
Mo Kꢃ radiation
Cell parameters from 122758
re¯ections
1
Ê
ꢀ
ꢄ = 2.9±25.7
ꢅ = 0.13 mm
T = 100 (2) K
� 1
ꢀ
Ê
Minutolo, F., Wilson, S. R. & Katzenellenbogen, J. A. (1999). Acta Cryst. C55,
3
Platelet, colourless
0.17 Â 0.15 Â 0.10 mm
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Nonius KappaCCD area-detector
diffractometer
Rint = 0.036
ꢀ
ꢄ
max = 25.7
'
and ! scans
h = � 35 ! 34
k = � 14 ! 0
l = 0 ! 17
1
9
6
22758 measured re¯ections
059 independent re¯ections
960 re¯ections with I > 2ꢆ(I)
Sulzbach, H. M., Bolton, E., Lenoir, D., von Ragu e Schleyer, P. & Schaefer,
H. F. (1996). J. Am. Chem. Soc. 118, 9908±9914.
ꢁ
o236 Villiers et al.
C H
9 20
N
2
33 2
and C27H N P
Acta Cryst. (2006). C62, o234±o236