Migratory insertion of the R2P group into a nitrogen-nitrogen bond - A novel type of rearrangement in phosphorus-nitrogen ligand chemistry. 3. The rearrangement of triphosphinohydrazide ligand -N(PPh2)- N(PPh2)2 to triphosphazenide anion {[Ph 2P-N]2PPh2}- in the coordination sphere of divalent cobalt and nickel

Article abstract of DOI:10.1021/ic701954k

Hydrazine dihydrochloride reacts with 3 equiv of Ph₂PCl in tetrahydrofuran in the presence of triethylamine to give tris(diphenylphosphino) hydrazine (1) in 70% yield. Each nitrogen atom in 1 has a trigonal-planar environment according to X-ray analysis. Thermolysis of 1 at 130°C results in the formation of two products: bis(diphenylphosphino)amine and octaphenylcyclotetraphosphazene. The interaction of free ligand 1 with NiBr ₂ affords a simple adduct [(Ph₂P)₂N-NH-PPh ₂]NiBr₂, while its anionic (hydrazide) form undergoes rearrangement in a coordination sphere of divalent cobalt and nickel involving migratory insertion of the Ph₂P group into a nitrogen-nitrogen bond. The reaction of 1 with cobalt bis(trimethylsilyl)amide, [(Me₃Si) ₂N]₂Co, yields the complex of phosphazenide-type (Me ₃Si)₂N-Co[(Ph₂PN)₂PPh₂] (2) in 86% yield. A similar reaction of 1 with nikelocene proceeds with substitution of one Cp ring to form durable 18-electron complex CpNi[(Ph ₂PN)₂PPh₂] (3).

Full text of DOI:10.1021/ic701954k

Inorg. Chem. 2008, 47, 2608-2612
Migratory Insertion of the R2P Group into a Nitrogen-Nitrogen Bond -
A Novel Type of Rearrangement in Phosphorus-Nitrogen Ligand
Chemistry. 3. The Rearrangement of Triphosphinohydrazide Ligand
-N(PPh2)-N(PPh2)2 to Triphosphazenide Anion {[(Ph2P-N]2PPh2}-
in the Coordination Sphere of Divalent Cobalt and Nickel
Vyacheslav V. Sushev, Natalia V. Belina, Georgy K. Fukin, Yuriy A. Kurskiy,
Alexander N. Kornev,* and Gleb A. Abakumov
RazuVaeV Institute of Organometallic Chemistry, Russian Academy of Sciences, 49 Tropinin Street,
603950 Nizhny NoVgorod, Russia
Received October 3, 2007
Hydrazine dihydrochloride reacts with 3 equiv of Ph2PCl in tetrahydrofuran in the presence of triethylamine to give
tris(diphenylphosphino)hydrazine (1) in 70% yield. Each nitrogen atom in 1 has a trigonal-planar environment according
to X-ray analysis. Thermolysis of 1 at 130 °C results in the formation of two products: bis(diphenylphosphino)amine
and octaphenylcyclotetraphosphazene. The interaction of free ligand 1 with NiBr2 affords a simple adduct
[(Ph2P)2N-NH-PPh2]NiBr2, while its anionic (hydrazide) form undergoes rearrangement in a coordination sphere
of divalent cobalt and nickel involving migratory insertion of the Ph2P group into a nitrogen-nitrogen bond. The
reaction of 1 with cobalt bis(trimethylsilyl)amide, [(Me3Si)2N]2Co, yields the complex of phosphazenide-type
(Me3Si)2N-Co[(Ph2PN)2PPh2] (2) in 86% yield. A similar reaction of 1 with nikelocene proceeds with substitution
of one Cp ring to form durable 18-electron complex CpNi[(Ph2PN)2PPh2] (3).
Introduction
R2P-NR′-NR*-M (M ) metal atom; R, R′, R* )
substituents of various natures), it was apparent that the
stability of the metal complexes containing a σ-bonded
phosphinohydrazide ligand {-NAr-NAr-PPh2} (Ar ) aryl)
is strongly dependent on the nature of the metal, its oxidation
state, and the ligand environment.6,7 Early and middle
transition metals or nontransition metals form stable phos-
phinohydrazides M[N(Ar)N(Ar)PPh2]n {M ) Li, Zn, Ge(II),
Mn(II), Cr(III), and Fe(II)}, while late transition metals (Co,
Ni, and Cu) and metals with an enhanced oxidation state
(Fe3+ in contrast to Fe2+) cause a transformation of the
phosphinohydrazide ligand.
The importance of rearrangements in phosphorus chem-
istry is difficult to overestimate. The Mikhaelis-Arbuzov
rearrangement and its numerous modifications1–5 gave a
powerful impetus to the development of synthetic phosphorus
chemistry. In this paper, we report a novel type of rear-
rangement in phosphorus-nitrogen ligand chemistry, which
is accompanied by the migratory insertion of an R2P group
into the nitrogen-nitrogen bond of a phosphinohydrazide
ligand: R2P-NR-NR- f RNdPR2-NR-. Formally, the
rearrangement is a redox process: three-valent, three-
coordinate phosphorus becomes four-coordinate P(V), while
a nitrogen atom reduces its coordination number to 2.
When we turned our attention to a novel amidophosphine
η2[P,σ-N]-ligand system, namely, phosphinohydrazide ligands,
We could then describe rearrangements of two kinds of
ligandssmonophosphinohydrazides6 and diphosphinohy-
drazides:7 This rearrangement is interesting not only in itself;
* Author to whom correspondence should be addressed. E-mail:
ligand@mail.ru.
(6) Fedotova, Y. V.; Kornev, A. N.; Sushev, V. V.; Kursky, Y. A.;
Mushtina, T. G.; Makarenko, N. P.; Fukin, G. K.; Abakumov, G. A.;
Zakharov, L. N.; Rheingold, A. L. J. Organomet. Chem. 2004, 689,
3060–3074.
(1) Arbuzov, B. A. Pure Appl. Chem. 1964, 9, 307.
(2) Ramirez, F. J. Am. Chem. Soc. 1960, 82, 2651.
(3) Brill, T. B.; Landon, S. J. Chem. ReV. 1984, 84, 577.
(4) Harvey, R.; De Sombre, E. Top. Phosphorus Chem. 1964, 1, 57.
(5) Gilyarov, V. A. Russ. Chem. ReV. 1978, 47, 870.
(7) Sushev, V. V.; Kornev, A. N.; Min’ko, Y. A.; Belina, N. V.; Kurskiy,
Y. A.; Kuznetsova, O. V.; Fukin, G. K.; Baranov, E. V.; Cherkasov,
V. K.; Abakumov, G. A. J. Organomet. Chem. 2006, 691, 879–889.
2608 Inorganic Chemistry, Vol. 47, No. 7, 2008
10.1021/ic701954k CCC: $40.75  2008 American Chemical Society
Published on Web 03/04/2008

Migratory Insertion of the R2P Group
Table 1. Crystal Data and Structure Analysis Results for 1–3
1
2
3 · (THF)
formula
Mr
space group
C36H31N2P3
584.54
C42H48CoN3P3Si2 C45H43N2NiOP3
802.85
monoclinic
P2(1)/c
9.7803(6)
31.657(2)
13.6636(8)
90
103.676(1)
90
4110.5(4)
4
779.43
monoclinic,
P2(1)/c
14.9713(10)
9.5166(6)
21.922(2)
90
103.129(1)°
90
3041.7(3)
4
1.276
triclinic
j
P1
a, Å
b, Å
c, Å
R
9.8206(5)
10.1212(5)
20.944(1)
100.428(1)
96.917(1)
107.854(1)
1914.02(16)
2
ꢀ (deg)
γ
V, Å3
Z
F
calcd, g cm3
T (K)
1.297
1.352
100(2)
1224
0.224
100(2)
1684
100(2)
816
F(000)
µ (mm-1
color
)
0.626
0.670
colorless
0.16 ×
brown
red-brown
0.50 ×
size (mm3)
0.43 ×
0.18 × 0.12
1.66–24.25
21096
0.10 × 0.08
1.91–25.06
16355
0.40 × 0.30
1.01–26.00
11438
θ (deg)
collected reflns
Figure 1. Molecular structure of 1. Hydrogen atoms are omitted for clarity.
independent reflns 5375
6638
7464
Rint
0.0377
1.029
0.0461
0.983
0.0140
1.042
GOF(F2)
R1 (I > 2σ(I))
wR2 (all data)
largest diff. peak
and hole eÅ-3
0.0490
0.1319
0.0389
0.0919
0.0332
0.0845
0.646/-0.250
0.736/-0.477 0.548 -0.220
Table 2. Selected Bond Distances (Å) and Angles (deg) for 1
P(1)-N(1)
1.712(2)
1.437(3)
1.728(2)
1.700(2)
N(1)-N(2)
N(1)-P(2)
N(2)-P(3)
N(1)-N(2)-P(3)
N(2)-N(1)-P(1)
N(2)-N(1)-P(2)
P(1)-N(1)-P(2)
N(1)-P(1)-C(1)
N(1)-P(1)-C(7)
C(1)-P(1)-C(7)
116.8(2)
it also represents a key to the synthesis of various useful
transition metal complexes of phosphazene and amidophosphine
types. Another interesting finding involving the rearrangement
of the triphosphinohydrazide ligand -N(PPh2)-N(PPh2)2 in the
coordination sphere of divalent cobalt and nickel is
117.8(2)
117.3(2)
124.8(1)
103.5(1)
104.2(1)
102.1(1)
trigonal-planar points to the significant reduction of basicity
in the nitrogen atoms. Table 1 displays the crystal data for
1; Table 2 depicts selected bond distances and angles. The
dihedral angle between the P(1)N(1)P(2) and HN(2)P(3)
planes is 49.6°. P-N and N-N bond lengths in the molecule
are typical for phosphazanes and phosphinohydrazines.7,8
Note, however, that the N(1)-N(2) bond distance, 1.437(3),
is somewhat longer than that found in monophosphinohy-
drazine analog PhNH-NPh-PPh2 (1.401(2)).6 The tris-
(diphenylphosphino)hydrazine is stable up to 130 °C, at
which temperature it decomposes to form two well-known
products: bis(diphenylphosphino)amine and octaphenylcy-
clotetraphosphazene. These products were separated and
characterized by IR, 31P NMR data, and melting points:
Results and Discussion
The starting tris(diphenylphosphino)hydrazine 1 (precursor
for the corresponding hydrazide ligand) is easily prepared
by the interaction of hydrazine dihydrochloride with 3 equiv
of chlorodiphenylphosphine in the presence of triethylamine.
Et3N/Et2O
Ph P N
(
)
2
2
3Ph2PC1 + N2H4 · 2HC1
8
- NH - PPh2
1
-5Et3N·HCl
Triphosphinohydrazine 1 forms relatively air-stable color-
less crystals. The 31P NMR spectrum of 1 in CDCl3 contains
a doublet (77.7 ppm) and a triplet (47.0 ppm) with splitting
constant JP,P ) 8.6 Hz. The 1H NMR spectrum of 1 exhibits
a doublet at 4.23 ppm (JH,P ) 8.5 Hz) assigned to the NH
group. Note that the NH group shows sharp and very weak
absorption (3270 cm-1) in the IR spectrum.
The molecular structure of 1, recorded at 100 K, shows
discrete molecular units (Figure 1). Each nitrogen atom in 1
has a trigonal-planar environment. The change of the nitrogen
atoms’ geometry from pyramidal (at free hydrazine) to
(8) Naumov, V. A.; Vilkov L. V. Molecular structures of organophos-
phorus compounds (in Russian); Nauka: Moscow, 1986; p 320.
Inorganic Chemistry, Vol. 47, No. 7, 2008 2609

Sushev et al.
Figure 2. Molecular structure of 2. Hydrogen atoms and Ph rings are omitted for clarity.
Table 3. Selected Bond Lengths [Å] and Angles [deg] for 2
The transformation of 1 may be described formally as a
hydrogen migration from one nitrogen atom to another and
the tetramerization of the remaining phosphanitrene {Ph2PN}.
Tris(diphenylphosphino)hydrazine as a free ligand forms
a stable complex with metal halides. Consequently, the
interaction of 1 with nickel dibromide gives a red adduct
1 · NiBr2. The IR spectrum of this compound is very similar
to the spectrum of free ligand 1 except for the shift of the
absorption band ν(NH) from 3270 to 3205 cm-1. Unlike the
free ligand, its anionic form, namely, tris(diphenylphosphi-
no)hydrazide-anion, undergoes rearrangement in the coor-
dination sphere of cobalt(II) and nickel(II).
Cobalt silylamide Co[N(SiMe3)2]2 reacts with 1 equiv of
tris(diphenylphosphino)-hydrazine (1) in toluene under mild
conditions over 24 h. We succeeded in separating a single
product of this reaction in 86% preparative yield, which was
proved to be the complex of phosphazenide type (2).
Co(1)-N(3)
1.845(2)
Co(1)-P(3)
2.1601(8)
2.1631(8)
1.617(2)
1.597(2)
1.608(2)
1.615(2)
Co(1)-P(1)
P(1)-N(1)
P(2)-N(1)
P(2)-N(2)
P(3)-N(2)
N(3)-Co(1)-P(3)
N(3)-Co(1)-P(1)
P(3)-Co(1)-P(1)
N(1)-P(1)-Co(1)
N(1)-P(2)-N(2)
N(2)-P(3)-Co(1)
P(2)-N(1)-P(1)
P(2)-N(2)-P(3)
135.51(7)
134.56(7)
89.32(3)
124.05(9)
117.6(1)
117.47(9)
124.7(1)
120.0(1)
bond distances and angles. The chelate P(3)-Co(1)-P(1)
angle is 89.32(3)°. The N-P bond distances in 2 are justified
and lie in the range 1.597(2)-1.617(2) Å, which is typical
for other known metal complexes with this ligand.9,10 The
Co-N bond distance (1.845(2)Å), in spite of the steric
bulkiness of 2, is the least among the other cobalt(II)
bis(trimethylsilyl)amido derivatives (1.90–2.06 Å11–14).
A similar rearrangement of the tris(diphenylphosphino)-
hydrazide anion occurs in the Ni(II) coordination sphere. The
reaction of 1 with dicyclopentadienylnickel proceeds by the
substitution of one Cp ring with a triphosphinohydrazide
ligand followed by rearrangement of the ligand. We suc-
ceeded in separating a single product (3) of this reaction in
88% preparative yield. The IR spectrum of the crystalline
It was not possible to isolate the originally formed
phosphinohydrazide complex (Me3Si)2N-Co[N(PPh2)-N-
(PPh2)2]. Attempts to stop the reaction at the initial period
of time gave only an intractable waxy solid.
The IR spectrum of 2 contains strong absorptions at 1245,
840, and 1155 cm-1 assigned to stretching vibrations of
Me3Si and PdN fragments, respectively. The X-ray inves-
tigation reveals the formation of a mixed-ligand complex
(Figure 2) with a central cobalt(II) atom in a rare trigonal-
planar environment (the sum of the angles at Co 359.41°).
Table 1 displays crystal data for 2; Table 3 shows selected
(9) Ellerman, J.; Sutter, J.; Schelle, C.; Knoch, F. A.; Moll, M. Z. Anorg.
Allg. Chem. 1993, 619, 2006–2014.
(10) Ellerman, J.; Schutz, M.; Heineman, F. W.; Moll, M.; Bauer, W. Z.
Naturforsch., B: Chem. Sci. 1997, 52, 795–800.
(11) Andersen, R. A.; Faegri, K.; Green, J. C.; Haaland, A.; Lappert, M. F.;
Leung, W.-P.; Rypdal, K. Inorg. Chem. 1988, 27, 1782.
(12) Murray, B. D.; Power, P. P. Inorg. Chem. 1984, 23, 4584–4588.
(13) Bartlett, R. A.; Power, P. P. J. Am. Chem. Soc. 1987, 109, 7563–
7564.
(14) Fryzuk, M. D.; Leznoff, D. B.; Thompson, R. C.; Rettig, S. J. J. Am.
Chem. Soc. 1998, 120, 10126.
2610 Inorganic Chemistry, Vol. 47, No. 7, 2008

Migratory Insertion of the R2P Group
product 3 differs significantly from the spectrum of 1 and
contains wide and strong absorptions in the region 1230–1050
cm-1 assigned to ν(PVdN) vibrations, as is typical for
phosphazenes.15
The 31P NMR spectrum of 3 represents the spin system
AA’X, showing a doublet at 65.0 ppm and a triplet at 30.5
ppm (JP,P) 34 Hz), assigned to PIII and PV, respectively. The
proton NMR spectrum of the complex contains a multiplet
in the aromatic region and a single resonance of Cp protons
at 4.9 ppm (30H, 5H, respectively), which is indicative of
the substitution of only one Cp ring. An X-ray investigation
confirms the formation of a mixed-ligand complex (Figure
3). Table 1 displays the crystal data for 3; Table 4 shows
selected bond distances and angles. No essential differences
in structures exist between cobalt and nickel metallocycles
[M(PNPNP)]. The chelate P(3)-Ni(1)-P(1) angle, 91.34(2)°,
is slightly broader than P(3)-Co(1)-P(1), 89.32(3)°, in 2.
The phosphorus and nitrogen atoms of the ligand lie in the
same plane with an average deviation of about 0.11 Å. The
dihedral angle between the plane of the ligand and the
P(1)Ni(1)P(3) plane is 139.2°.
The mechanism of this last reaction invites mention of an
important observation. After mixing the tetrahydrofuran
(THF) solutions of the starting reagents (1 and Cp2Ni), a
noncrystalline greenish-yellow precipitate forms. The IR
spectrum of this substance showed intense absorption at 2490
and 2010 cm-1, indicating the presence of charged nitrogen
(NH)+ in the molecule. At the same time, the absorption
band of the Cp ring (773 cm-1 in Cp2Ni) is shifted to 837
cm-1 in an intermediate product, which suggests that
elimination of the Cp group is accompanied by charge
separation.
Figure 3. Molecular structure of 3. Hydrogen atoms are omitted for clarity.
Table 4. Selected Bond Lengths [Å] and Angles [deg] for 3
Ni(1)-P(1)
2.1557(5)
2.1594(5)
1.597(2)
1.598(2)
1.613(2)
Ni(1)-P(3)
P(2)-N(2)
P(2)-N(1)
P(1)-N(1)
P(3)-N(2)
1.620(2)
Ni(1)-C(5)
2.094(2) (min)
2.151(2) (max)
91.34(2)
116.58(6)
118.89(6)
122.66(9)
118.91(8)
125.62(9)
Ni(1)-C(4)
P(1)-Ni(1)-P(3)
N(1)-P(1)-Ni(1)
N(2)-P(3)-Ni(1)
P(2)-N(1)-P(1)
N(2)-P(2)-N(1)
P(2)-N(2)-P(3)
The tendency of the phosphinohydrazide system toward
rearrangement depends on several factors: (1) the energy of
the M-N σ-bond, which is usually weakened on going from
early to late transition metals, (2) the energy of the N-N
bond, which strongly depends on the nature of the substit-
uents on the nitrogen atoms, and (3) the energy of the
metal-phosphorus bond, which is determined by a combina-
tion of electronic effects of direct and back-donation between
metal and phosphorus atoms.
Our preliminary study showed that ligands containing
phosphito groups (e.g., (ArO)2P-NPh-NPh-) are prone
to rearrangement at the coordination sphere of Co and
Ni, while ligands bearing donor isopropyl- and tert-butyl
substituents (i-Pr2P-NPh-NPh- and t-Bu2P-NPhNPh-)
give stable metal complexes. It is also worth noting that
a negative charge at the nitrogen atom of the hydrazide
moiety destabilizes the molecule. The lithium salt of
tris(diphenylphosphino)hydrazine (Ph2P)2N-N(PPh2)Li is
unstable and decomposes during the synthetic procedure
even at low temperatures. However, other lithium phos-
phinohydrazides (e.g., Ph2P-NPh-NPh-Li, (Ph2P)2N-
NPhLi, i-Pr2P-NPhNPhLi, t-Bu2P-NPh-NPh-Li,
Ph2P-N(CH2Ph)-N(CH2Ph)Li) may be handled without
restrictions.
Since compound 3 is an 18-electron complex, it demon-
strates high stability and may be kept in open air for a long
time without change. Substitution of the second Cp ring for
the (Ph2P)3N2 ligand is not observed. Instead, cobalt complex
2 reacts with the second mole of the ligand to form a product
of full substitution, Co(PPh2-NdPPh2-NPPh2)2. This prod-
uct was characterized using elemental analysis and the IR
spectrum, which was identical to the sample of
Co(PPh2-NdPPh2-NPPh2)2 described earlier.16
(15) Richards, P. I.; Steiner, A. Inorg. Chem. 2004, 43, 2810–2817.
(16) Ellerman, J.; Sutter, J.; Schelle, C.; Knoch, F. A.; Moll, M. Z. Anorg.
Allg. Chem. 1993, 619, 2006.
Our research shows that the chemistry of phosphinohy-
drazide ligands is exceedingly varied and may serve as a
Inorganic Chemistry, Vol. 47, No. 7, 2008 2611

Sushev et al.
NiBr2 · 2THF (0.20 g, 0.55 mmol). The mixture was vigorously
shaken at 20 °C for 3 h until all nickel bromide was dissolved and
then was kept for 24 h. Adduct 1·NiBr2 formed as a poorly soluble,
fine crystalline, red precipitate. Yield: 0.43 g (97.4%). Anal. Calcd
for C36H31N2P3NiBr2, %: C, 53.82; H, 3.86; Ni, 7.31. Found, %:
C, 54.21; H, 4.15; Ni, 7.11. IR (nujol), ν/cm-1: 3205w, 1585w,
1310w, 1190ww, 1155ww, 1095m, 920m, 850ww, 805w, 743m,
693s, 607w, 513m, 493m.
key to the synthesis of various useful transition metal
complexes of phosphazene and amidophosphine types.
Experimental Section
Solvents were purified following standard methods.17 Toluene
was thoroughly dried and distilled over P2O5 prior to use. Ether
and THF were dried and distilled over Na/benzophenone. Cobalt
silylamide Co[N(SiMe3)2]2 was prepared according to known
methods.11,18 All manipulations were performed with rigorous
exclusion of oxygen and moisture, in a vacuum or under an argon
atmosphere using standard Schlenk techniques. Hexamethyldisila-
zane liberated in the course of the metal silylamides reactions was
detected by gas chromatographic analyses with a Tsvet-500 device,
equipped with stainless steel columns 0.4 cm × 200 cm, packed
with 5% SE-30 on Chromatone N-Super, with a thermoconductivity
detector and using helium as the carrier gas. The spectrophotometric
determination of cobalt and nickel in the prepared compounds was
provided by the methods described in ref 19. Infrared spectra were
recorded on a Perkin-Elmer 577 spectrometer from 400 to 4000
cm-1 in nujol. NMR spectra were recorded in CDCl3 or C6D6
solutions using a Bruker DPX-200 device. X-ray data were collected
on a Bruker AXS SMART APEX diffractometer (graphite mono-
chromator, Mo KR radiation (λ ) 0.71073 Å), ꢁ-ω scan).
Preparation of Tris(Diphenylphosphino)Hydrazine (1). Et3N
(4.81 g, 47.6 mmol) in THF was added to a mixture of hydrazine
dihydrochloride (1.06 g, 9.5 mmol) and Ph2PCl (6.28 g, 28.5 mmol)
in THF (15 mL). The mixture was stirred for 24 h at 20 °C and
then filtered. Next, the THF was removed in a vacuum and
exchanged with toluene. Then, the solution was concentrated to
∼7 mL. Keeping the mixture overnight at 10 °C yielded large
colorless crystals of 1. Yield: 3.90 g (70%). Anal. Calcd for
C36H31N2P3, %: C, 73.97; H, 5.31; P, 15.93. Found, %: C, 74.03;
H, 5.12; P, 16.08. IR (nujol), ν/cm-1: 3270ww, 1430m, 1300w,
1180w, 1150w, 1090m, 1070w, 1020w, 1000w, 910m, 820w, 740m,
720w, 700m, 630w, 550w, 520w, 490w. 31P{1H} NMR (C6D6,
300κ), δ (ppm): 77.8 (d), 47.1 (t) {JP,P ) 9 Hz}.
Preparation of [Ph2P(NPPh2)2]Co[N(SiMe3)2] (2). A mixture
of toluene solutions of 1 (0.29 g, 0.5 mmol, 10 mL) and
Co[N(SiMe3)2]2 (0.19 g, 0.5 mmol, 5 mL) was kept at 20 °C for
24 h. Toluene was then removed under reduced pressure and
changed for ether (10 mL). Yellow-brown crystals of the product,
which formed overnight, were washed with cold ether and dried in
a vacuum. Yield: 0.34 g (86%). Anal. Calcd for C42H48Si2P3N3Co,
%: C, 62.83; H, 6.03; Co, 7.44. Found, %: C, 62.75; H, 6.10; Co,
7.42. IR (nujol), ν/cm-1: 1245m, 1155m, 1120m, 1065w, 1025w,
985w, 930w, 885m, 840s, 745m, 725m, 695 vs, 570w, 540m, 515s.
Preparation of [Ph2P(NPPh2)2]NiCp (3). A THF solution of 1
(0.58 g, 1.0 mmol, 10 mL) was added to a solution of Cp2Ni (0.19
g, 1.0 mmol, 10 mL). A yellow-green precipitate formed in about
5 min. A sample of the precipitate was washed with THF, dried in
a vacuum, and studied by IR spectroscopy (nujol), ν/cm-1
:
3100–3200 sw, 2490m, 2010m, 1765s, 1307w, 1273w, 1177s,
1107s, 1025w, 996w, 903m, 837m, 809w, 798w, 747s, 724s, 694vs,
520s, 497m. Following heating at 60 °C for 5 h, the precipitate
was dissolved, and the solution turned red-brown. The main part
of the solvent was removed under reduced pressure. Red crystals
of 3 formed overnight at room temperature. The crystals were
washed with cold THF and dried in a vacuum. Yield: 2.38 g (88%).
Anal. Calcd for C41H35P3N2Ni, %: C, 69.62; H, 4.95; Ni, 8.31.
Found, %: C, 69.44; H, 5.04; Ni, 8.22. IR (nujol), ν/cm-1: 3050w,
1580w, 1430m, 1340w, 1300w, 1180s, 1160s, 1130s, 1090m,
1070m, 1020m, 1000w, 900w, 830w, 820m, 790m, 740m, 720m,
690m, 570m, 530s, 500m, 440w. 31P{1H} NMR (C6D6, 300κ) δ
(ppm): 65.2 (d), 30.4 (t) {2J ) 34 Hz}. 1H NMR: 8.3–6.9 (m, 30H,
(C6H5)), 4.9 (s, 5H, (Cp)).
The thermolysis of 1 was carried out in a vacuum line (0.01
mm) with a heating rate of 3°/min. The sample (0.1 g) melted at
128–130 °C, and then spontaneous boiling (for 10–15 s) was
observed. The sample was kept at 130 °C for 5 min, and then the
mixture of toluene and diethyl ether (1:1) was added. Bis(diphe-
nylphosphino)amine, (Ph2P)2NH, became a solution while poorly
soluble octaphenylcyclotetraphosphazene {(-Ph2PdN-)4} sepa-
rated out as colorless crystals. Repeated crystallization gave pure
crystals of both compounds.
All structures were solved by direct methods and refined against
F2 on all data by full-matrix least squares with SHELXTL.21
Absorption correction was applied using SADABS.22
Acknowledgment. We are grateful to the Russian Foun-
dation for Basic Research (Grant 06-03-32728-a; scientific
school 4947.2006.3) for financial support of this work. We
would also like to thank Prof. Robert West for a critical
reading of this manuscript and Prof. Petey Young for help
in preparation of the manuscript.
(Ph2P)2NH. 31P{1H} NMR (C6D6, 300κ), δ: 44.0 ppm. IR (nujol),
ν/cm-1: 3230m, 3050m, 1430 c, 1250m, 1100c, 1020m, 1000w,
900vs, 730vs, 600vs, 520s.
{(-Ph2PdN-)4}. 31P{1H} NMR (C6D6, 300κ), δ: 14.0 ppm. mp:
317–319 °C (lit. data: 319–321 °C 20). IR (nujol): 1220vs, 1175w,
1117m, 1928w, 885m, 742w, 722m, 693s, 567m, 513s. Anal. Calcd
for C48H40P4, %: C, 72.36; H, 5.06; P, 15.55. Found, %: C, 72.44;
H, 5.10; P, 15.34.
Supporting Information Available: CIF files of the study
compounds. This material is available free of charge via the Internet
at http://pubs.acs.org. CCDC 652102 (1), 652103 (2), and 652104 (3)
contain the supplementary crystallographic data for this paper. This
data can be obtained free of charge from the Cambridge Crystal-
lographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Preparation of [(Ph2P)2NNHPPh2)]NiBr2. A solution of 1 (0.32
g, 0.55 mmol) in 15 mL of THF was added to a powder of
(17) Perrin, D. D.; Armarego, W. L. F.; Perrin, D. R. Purification of
Laboratory Chemicals; Pergamon: Oxford, U.K., 1980.
(18) Burger, H.; Wannagat, U. Monatsh. Chem. 1963, 94, 1007.
(19) Upor, E.; Mohai M.; Novak, Gy. Photometric methods in inorganic
trace analysis; Academiai Kiado: Budapest 1985.
(20) Haber, C. P.; Herring, D. L.; Lawton, E. A. J. Am. Chem. Soc. 1958,
80, 2116.
IC701954K
(21) Sheldrick, G. M. SHELXTL, Structure Determination Software Suite,
v. 6.12; Bruker AXS: Madison, WI, 2000.
(22) Sheldrick. G. M. SADABS, Bruker/Siemens Area Detector Absorption
Correction Program, v. 2.01; Bruker AXS: Madison, WI, 1998.
2612 Inorganic Chemistry, Vol. 47, No. 7, 2008