Differing reactivities of (trimpsi)M(CO)2(NO) complexes [M = V, Nb, Ta; trimpsi = tBuSi(CH2PMe2)3] with halogens and halogen sources

Article abstract of DOI:10.1021/ic020340g

Treatment of (trimpsi)V(CO)₂(NO) (trimpsi: rBuSi(CH₂PMe₂)₃) with 1 equiv of PhlCl₂ or C₂Cl₆ or 2 equiv of AgCl affords (trimpsi)V(NO)Cl₂ (1) in moderate yields. Likewise, (trimpsi)V(NO)Br₂ (2) and (trimpsi)V(NO)l₂ (3) are formed by the reactions of (trimpsi)V(CO)₂(NO) with Br₂ and l₂, respectively. The complexes (trimpsi)M(NO)l₂(PMe3) (M = Nb, 4; Ta, 5) can be isolated in moderate to low yields when the (trimpsi)M(CO)₂(NO) compounds are sequentially treated with 1 equiv of 12 and excess PMe₃. The reaction of (trimpsi)V(CO)₂(NO) with 2 equiv of CINO forms 1 in low yield, but the reactions of (trimpsi)M(CO)₂(NO) (M = Nb, Ta) with 1 equiv of CINO generate (trimpsi)M(NO)₂Cl (M = Nb, 6; Ta, 7). Complexes 6 and 7 are thermally unstable and decompose quickly at room temperature; consequently, they have been characterized solely by IR and ³¹ P{¹H} NMR spectroscopies. All other new complexes have been fully characterized by standard methods, and the solid-state molecular structures of 1·3CH₂Cl₂, 4·(3/4)CH₂Cl₂, and 5·THF have been established by single-crystal X-ray diffraction analyses. A convenient method of generating Cl¹⁵NO has also been developed during the course of these investigations.

Full text of DOI:10.1021/ic020340g

Inorg. Chem. 2002, 41, 5388−5396
Differing Reactivities of (trimpsi)M(CO) (NO) Complexes [M ) V, Nb, Ta;
2
t
trimpsi ) BuSi(CH PMe ) ] with Halogens and Halogen Sources
2
2 3
Trevor W. Hayton, Peter Legzdins,* and Brian O. Patrick
Department of Chemistry, The UniVersity of British Columbia, VancouVer, British Columbia,
Canada V6T 1Z1
Received May 13, 2002
t
Treatment of (trimpsi)V(CO)
affords (trimpsi)V(NO)Cl
by the reactions of (trimpsi)V(CO)
Nb, 4; Ta, 5) can be isolated in moderate to low yields when the (trimpsi)M(CO)
treated with 1 equiv of I and excess PMe . The reaction of (trimpsi)V(CO) (NO) with 2 equiv of ClNO forms 1 in
low yield, but the reactions of (trimpsi)M(CO) (NO) (M ) Nb, Ta) with 1 equiv of ClNO generate (trimpsi)M(NO) Cl
M ) Nb, 6; Ta, 7). Complexes 6 and 7 are thermally unstable and decompose quickly at room temperature;
2
(NO) (trimpsi ) BuSi(CH
2
PMe
2
)
3
) with 1 equiv of PhICl
(2) and (trimpsi)V(NO)I
, respectively. The complexes (trimpsi)M(NO)I
(NO) compounds are sequentially
2
or C
2
Cl
6
or 2 equiv of AgCl
(3) are formed
(PMe ) (M)
2
(1) in moderate yields. Likewise, (trimpsi)V(NO)Br
(NO) with Br and I
2
2
2
2
2
2
3
2
2
3
2
2
2
(
31
1
consequently, they have been characterized solely by IR and P{ H} NMR spectroscopies. All other new complexes
have been fully characterized by standard methods, and the solid-state molecular structures of 1‚3CH Cl , 4‚(3/
)CH Cl , and 5‚THF have been established by single-crystal X-ray diffraction analyses. A convenient method of
2
2
4
2
2
15
generating Cl NO has also been developed during the course of these investigations.
6
8
Introduction
all are {M(NO)} -type species. Vanadium nitrosyls are
9
,10
almost as rare.
The most common class of vanadium
Ongoing research in our laboratories is focused on the
6
nitrosyls involves {V(NO)} -type complexes, examples of
which include V(L)
compounds (L ) neutral Lewis base).
derivatives of Cp′M(CO)
2
NO (Cp′ ) Cp, Cp*; M ) Mo,
for
which a substantial chemistry has been developed. Cp′M-
NO)R -type complexes are synthesized from the corre-
sponding dichloro precursors, Cp′M(NO)Cl , which are made
. The isolation of the
+
x
(CO)5-x(NO)- and [V(L)
4
(NO)
2
] -type
W), specifically the 16e bis(alkyl) species Cp′M(NO)R
2
11-20
4
A few {V(NO)} -
1
,2
(
2
(6) Barybin, M. V.; Young, V. G., Jr.; Ellis, J. E. Organometallics 1999,
18, 2744-2746.
2
(
7) Barybin, M. V.; Young, V. G., Jr.; Ellis, J. E. J. Am. Chem. Soc. 1999,
3
by treating Cp′M(CO)
isoelectronic (trimpsi)M(NO)X
CH PMe ; M ) V, Nb, Ta; X ) Cl, Br, I), synthesized in
similar fashion from the known 18e precursors (trimpsi)M-
2
NO with PCl
5
121, 9237-9238.
t
(8) Feltham, R. D.; Enemark, J. H. Top. Stereochem. 1981, 12, 155-
2
complexes (trimpsi ) BuSi-
215.
(
2
2 3
)
(
9) Hayton, T. W.; Legzdins, P.; Sharp, W. B. Chem. ReV. 2002, 102,
935-992.
(
10) Richter-Addo, G. B.; Legzdins, P. Metal Nitrosyls; Oxford University
4
(
2
CO) (NO), would be of considerable interest given the
Press: New York, 1992.
current paucity of group 5 nitrosyl complexes. Only two
(11) Werner, R. P. M. Z. Naturforsch., B: Chem. Sci. 1961, 16, 478-479.
(
12) Schiemann, J.; Weiss, E. J. Organomet. Chem. 1982, 232, 229-232.
13) Schiemann, J.; Weiss, E.; N a¨ umann, F.; Rehder, D. J. Organomet.
Chem. 1982, 232, 219-227.
niobium nitrosyls and three tantalum nitrosyls are cur-
(
5
rently known, namely (trimpsi)M(CO)
2
(NO), [M(CNAr)
4
-
+
),6 and Ta(NO)(CNAr)
7
(14) Fjare, K. L.; Ellis, J. E. J. Am. Chem. Soc. 1983, 105, 2303-2307.
(NO)
2
] (Ar ) 2,6-Me
2
C
6
H
3
5
, and
(15) N a¨ umann, F.; Rehder, D. Z. Naturforsch., B: Chem. Sci. 1984, 39,
1
647-1653.
*
Author to whom correspondence should be addressed. E-mail: legzdins@
(16) N a¨ umann, F.; Rehder, D. Z. Naturforsch., B: Chem. Sci. 1984, 39,
chem.ubc.ca.
1654-1661.
(
(
(
(
(
1) Adams, C. S.; Legzdins, P.; Tran, E. J. Am. Chem. Soc. 2001, 123,
(17) T o¨ fke, S.; Behrens, U. Acta Crystallogr., Sect. C 1986, C42, 161-
612-624.
163.
2) Sharp, W. B.; Daff, P. J.; McNeil, W. S.; Legzdins, P. J. Am. Chem.
Soc. 2001, 123, 6272-6282.
(18) Shi, Q.; Richmond, T. G.; Trogler, W. C.; Basolo, F. Inorg. Chem.
1984, 23, 957-960.
3) Dryden, N. H.; Legzdins, P.; Batchelor, R. J.; Einstein, F. W. B.
Organometallics 1991, 10, 2077-2081.
(19) N a¨ umann, F.; Rehder, D.; Pank, V. Inorg. Chim. Acta 1984, 84, 117-
123.
4) Hayton, T. W.; Daff, P. J.; Legzdins, P.; Patrick, B. O. Inorg. Chem.
(20) Mallik, M.; Ghosh, P. N.; Bhattacharyya, R. J. Chem. Soc., Dalton.
2
002, 41, 4114-4126.
5) Daff, P. J.; Legzdins, P.; Rettig, S. J. J. Am. Chem. Soc. 1998, 120,
688-2689.
Trans. 1993, 1731-1736.
(21) Griffith, W. P.; Lewis, J.; Wilkinson, G. J. Chem. Soc. 1959, 1632-
2
1633.
5388 Inorganic Chemistry, Vol. 41, No. 21, 2002
10.1021/ic020340g CCC: $22.00 © 2002 American Chemical Society
Published on Web 09/19/2002

2
ReactiWities of (trimpsi)M(CO) (NO) Complexes
3
- 21-23
type complexes, such as [V(CN)
5
(NO)] ,
6
[V(CN) -
are also
4- 24-26
- 27,28
(
NO)] ,
known.
This contribution describes the reactivity of (trimpsi)M-
CO) (NO) complexes with halogens, such as Br and I
and halogen sources, such as PCl and iodobenzene dichlo-
ride (PhICl ). The reactions of the (trimpsi)M(CO) (NO)
and [V(NO)(N(CH
2
CH
2
O)
3
)] ,
(
2
2
2
,
5
2
2
species with nitrosyl chloride (ClNO) are also outlined. These
transformations are of interest since ClNO is well-known in
inorganic chemistry as both a chlorinating and a nitrosylating
1
0
agent. For instance, ClNO reacts with CpM(CO)
2
(NO)
Cl complexes in high
In contrast, treatment of Mn (CO)10 with
Cl as the only isolable
(NO) reacts with excess ClNO
via the dinitrosyl intermediate,
(
M ) Cr, Mo, W) to form CpM(NO)
2
2
9
yields.
2
excess ClNO produces Mn(CO)
product. Also, Tp*Mo(CO)
to form Tp*Mo(NO)Cl
5
30
2
2
3
1
Tp*Mo(NO)
2
Cl.
Results and Discussion
Formation of (trimpsi)V(NO)X
Solutions of (trimpsi)V(CO) (NO) in CH
at -78 °C to generate yellow solutions of
(1) with the concomitant evolution of CO
eq 1). Crystallization of the reaction residue from CH Cl
2
(X ) Cl, Br, I).
Figure 1. ORTEP diagram of (trimpsi)V(NO)Cl2 (1) with thermal
ellipsoids at the 50% probability level.
2
2
2
Cl react with 1
32
equiv of PhICl
2
1
the expected three methyl environments of the trimpsi
(trimpsi)V(NO)Cl
2
ligand are evinced by virtual triplets at 1.68 and 1.89 ppm
and a doublet at 1.03 ppm. Each of these signals appears as
(
2
2
1
31
a singlet in the H{ P} NMR spectrum.
In an attempt to improve the yield of 1, three other
3
3
chlorinating reagents were tried, namely AgCl, hexachlo-
34
3
roethane (C
2 6 5 2
Cl ), and PCl . Treatment of (trimpsi)V(CO) -
(NO) with excess AgCl at room temperature leads to the
formation of 1 in 51% isolated yield and the concomitant
deposition of silver metal. The use of AgCl is particularly
convenient since excess AgCl can be added with no apparent
deleterious effects. Refluxing a CH
CO) (NO) and 1 equiv of C Cl
yield after crystallization from CH
between (trimpsi)V(CO) (NO) and 1 equiv of PCl
Cl at -78 °C leads to evolution of a gas and the formation
of an insoluble white precipitate. This precipitate shows no
bands in its IR spectrum attributable to a nitrosyl ligand and
proves to be intractable. Regrettably, none of these routes
provides 1 in higher yields than does the synthesis using
2
Cl
for 4 h gives 1 in 37%
Cl . Finally, the reaction
in CH
2
solution of (trimpsi)V-
(
2
2
6
affords 1 as a yellow crystalline material in 60% yield. In
the solid state, 1 is stable in air for several hours and exhibits
2
2
2
-
-
1
2
5
a ν(NO) at 1601 cm (Nujol), a frequency higher than that
-
1
4
2
2
of (trimpsi)V(CO) (NO) (1543 cm , Nujol). The room-
temperature 31P{ H} NMR and H NMR spectra of 1 are
1
1
consistent with the proposed formulation and the expected
1
C
S
molecular symmetry. For instance, the 31P{ H} NMR
spectrum in CD
ppm (1P) and -0.1 ppm (2P). In the H NMR spectrum of
2 2
Cl consists of two broad singlets at -24.5
PhICl
Crystals of 1‚3CH
analysis can be grown from a saturated CH
2
as the chlorinating agent.
Cl suitable for X-ray diffraction
Cl solution. The
1
2
2
2
2
(
(
(
22) Jagner, S.; Vannerberg, N. Acta Chem. Scand. 1968, 22, 3330-3331.
23) Jagner, S.; Vannerberg, N. Acta Chem. Scand. 1970, 24, 1988-2002.
24) M u¨ ller, A.; Werle, P.; Diemann, E.; Aymonino, P. J. Chem. Ber. 1972,
solid-state molecular structure of 1 is shown in Figure 1,
and its pertinent bond lengths and bond angles are collected
in Table 1. Somewhat surprisingly, 1, formally a 16e
complex, remains monomeric in the solid state rather than
associating through chloride bridges. Unfortunately, the
nitrosyl ligand is disordered between the three coordination
sites not occupied by phosphines. Furthermore, the nitrosyl
ligand is distributed unevenly between the three sites, the
relative occupancies being 0.68, 0.21, and 0.11. This type
of structural disorder is relatively common in metal-nitrosyl
1
05, 2419-2420.
25) Drew, M. G. B.; Pygall, C. F. Acta Crystallogr., Sect. B 1977, B33,
838-2842.
26) Jagner, S.; Ljungstr o¨ m, E. Acta Crystallogr., Sect. B 1978, B34, 653-
56.
(
(
(
(
2
6
27) Wieghardt, K.; Kleine-Boymann, M.; Swiridoff, W.; Nuber, B.; Weiss,
J. J. Chem. Soc., Dalton. Trans. 1985, 2493-2497.
28) Kitagawa, S.; Munakata, M.; Ueda, M. Inorg. Chim. Acta 1989, 164,
4
9-53.
(
(
29) Legzdins, P.; Malito, J. T. Inorg. Chem. 1975, 14, 1875-1878.
30) Kolthammer, B. W. S.; Legzdins, P.; Malito, J. T. Inorg. Chem. 1977,
1
6, 3173-3178.
3
5
(
(
31) Trofimenko, S. Inorg. Chem. 1969, 8, 2675-2680.
32) Witte, P. T.; Meetsma, A.; Hessen, B. Organometallics 1999, 18,
complexes, and it precludes accurate determination of the
V-N and N-O bond distances and the V-N-O bond angle.
2
944-2946.
33) Calderazzo, F.; Pampaloni, G.; Zanazzi, P. F. Chem. Ber. 1986, 119,
796-2814.
(
2
(34) Appel, R.; Sch o¨ ler, H. Chem. Ber. 1977, 110, 2382-2384.
Inorganic Chemistry, Vol. 41, No. 21, 2002 5389

Hayton et al.
-
1
Table 1. Selected Bond Lengths (Å) and Bond Angles (deg) for
(
IR spectrum having a single ν(NO) at 1607 cm (Nujol)
trimpsi)V(NO)Cl2 (1)a
1
31
1
and H and P{ H} NMR spectra resembling those of 1 and
Bond Lengths
2.
V(1)-Cl(1)
V(1)-Cl(2)
V(1)-Cl(3)
V(1)-P(1)
V(1)-P(2)
V(1)-P(3)
2.316(2)
V(1)-N(1)
V(1)-N(2)
V(1)-N(3)
N(1)-O(1)
N(2)-O(2)
N(3)-O(3)
1.690(8)
1.55(2)
1.58(2)
1.20(1)
1.21(5)
1.21(3)
Several attempts to form the congeneric difluoro complex,
2.356(1)
2.343(7)
2.542(1)
2.578(1)
2.528(1)
(
trimpsi)V(NO)F
of (trimpsi)V(CO)
AgF afforded no tractable products. The attempted metath-
esis of (trimpsi)V(NO)Cl with NaF or AgF also failed to
provide an isolable nitrosyl complex.
Formation of (trimpsi)M(NO)I (PMe
The reaction of (trimpsi)Nb(CO) (NO) with I
78 °C results in the formation of a pale orange solution
2
, were unsuccessful. For instance, oxidation
2
(NO) with 2 equiv of AgF or 1 equiv of
2
2
Bond Angles
Cl(1)-V(1)-P(1)
Cl(1)-V(1)-P(2)
Cl(1)-V(1)-P(3)
Cl(2)-V(1)-P(1)
Cl(2)-V(1)-P(2)
Cl(2)-V(1)-P(3)
Cl(3)-V(1)-P(1)
Cl(3)-V(1)-P(2)
Cl(3)-V(1)-P(3)
P(3)-V(1)-N(1)
P(3)-V(1)-N(2)
P(3)-V(1)-N(3)
86.00(6)
89.42(6)
168.45(6)
168.99(5)
85.50(4)
90.50(5)
88.8(1)
170.1(2)
86.2(2)
86.2(3)
P(1)-V(1)-P(2)
P(1)-V(1)-P(3)
P(1)-V(1)-N(1)
P(1)-V(1)-N(2)
P(1)-V(1)-N(3)
P(2)-V(1)-P(3)
P(2)-V(1)-N(1)
P(2)-V(1)-N(2)
P(2)-V(1)-N(3)
V(1)-N(1)-O(1)
V(1)-N(2)-O(2)
V(1)-N(3)-O(3)
84.99(3)
83.23(4)
93.0(2)
170.8(1)
90.2(7)
85.50(4)
171.7(3)
86(1)
2
3
) (M ) Nb, Ta).
in CH Cl at
2
2
2
2
-
and a pale yellow precipitate. No absorptions attributable to
a nitrosyl ligand are evident in the IR spectra of the
precipitate or the solution. Attempts to ascertain the identity
of any of the products formed have proven to be fruitless.
Similar results have been obtained for the reaction between
93.5(7)
173.7(7)
136(3)
96.6(1)
173.4(7)
159(2)
(
trimpsi)Ta(CO)
as Br , PCl , and PhICl
materials.
Given the stability of (trimpsi)V(NO)X
it is not unreasonable to assume that (trimpsi)M(NO)X
2
(NO) and I
2
. The use of other oxidants such
a
The NO and Cl ligands are mutually disordered.
2
5
2
has also yielded unidentifiable
The average V-P distance of 2.55 Å in 1 is slightly longer
than the average V-P bond length extant in (trimpsi)V(CO)
2
(X ) Cl, Br, I),
(M
Nb, Ta) species may well be generated during the reactions
2
-
2
4
(
NO) (2.47 Å).
Reaction of 1 equiv of Br
CH Cl
yellow as (trimpsi)V(NO)Br
)
2
with (trimpsi)V(CO)
2
(NO) in
2
of (trimpsi)M(CO) (NO) with halogens but that they sub-
2
2
at -78 °C results in a color change from red to
(2) is formed (eq 2). Complex
sequently decompose. Consistent with this view is the
following observation. When (trimpsi)Nb(CO) (NO) is al-
lowed to react with 1 equiv of I at -78 °C for approximately
0 s and excess PMe is then added via syringe, a clear
yellow solution forms. Crystallization of the reaction residue
from THF/hexanes affords (trimpsi)Nb(NO)I (PMe ) (4) as
a yellow powder in 64% yield (eq 3). The related (trimpsi)-
2
2
2
2
3
2
3
2
Cl
2
can be isolated in 82% yield by crystallization from CH -
/pentane (2:1) and exhibits a ν(NO) at 1589 cm- (Nujol),
1
2
very close to that observed for 1. Indeed, the spectroscopic
properties of 2 are practically identical to those exhibited
by 1.
3
Yellow crystals of 2 can be grown from CHCl and have
been subjected to an X-ray diffraction analysis, but again
severe positional disorder is evident in the solid-state
molecular structure. In this instance the greater electron
density of the bromide ligands effectively masks the positions
of the N and O atoms of the nitrosyl ligand, thereby making
it impossible to extract any meaningful metrical parameters.
Nevertheless, the X-ray crystallographic analysis does con-
firm the anticipated atom connectivity.
Ta(NO)I
2 3
(PMe ) (5) can be isolated in an identical manner
in 10% yield. Complexes 4 and 5 exhibit extremely low ν-
(NO) values of 1467 and 1450 cm (KBr), respectively, in
-
1
3
6
their IR spectra. To our knowledge, these represent the
lowest recorded values for a terminal nitrosyl ligand and
document the very strong MfNO back-bonding present in
these early-metal nitrosyl complexes. The P{ H} NMR
spectrum of 4 in CD Cl at room temperature consists of
three broad singlets at -10.1 ppm (2P), -14.7 ppm (1P),
3
1
1
2
2
Finally, reaction of 1 equiv of I
NO) in CH Cl at -78 °C results in a color change from
red to purple as (trimpsi)V(NO)I (3) is formed (eq 2).
2 2
with (trimpsi)V(CO) -
1
and -45.7 ppm (1P). The H NMR spectrum of 4 in CD
Cl contains the signals anticipated for the trimpsi ligand in
a C symmetric environment along with a doublet attributable
to the PMe ligand. Complex 5 decomposes quickly in CD
8
Cl , but in THF-d at room temperature it exhibits a H NMR
2
-
(
2
2
2
2
Crystallization from THF/hexanes (3:1) provides 3‚THF as an
analytically pure purple powder. This material exhibits an
S
3
2
-
1
2
(
35) Stowell, G. W.; Whittle, R. R.; Whaley, C. M.; White, D. P.
15
-1
Organometallics 2001, 20, 1050-1052.
(36) The ν(NO) value for 5- N is 1399 cm (KBr).
5390 Inorganic Chemistry, Vol. 41, No. 21, 2002

2
ReactiWities of (trimpsi)M(CO) (NO) Complexes
Figure 3. ORTEP diagram of (trimpsi)Nb(NO)I2(PMe3) (4) with thermal
ellipsoids at the 50% probability level.
Figure 2. (a) The AB2 portion of the AB2X pattern exhibited by 5 in its
31
1
P{ H} NMR spectrum. (b) The X portion of the AB2X pattern exhibited
by 5. Simulated spectra are shown as insets.
spectrum similar to 4. The 31P{ H} NMR spectrum of 5
1
consists of an AB
15.9 ppm (3P) and -54.0 ppm (1P) (Figure 2). The signal
at -15.9 ppm is the sum of A and B, most likely the two
2
X pattern with two multiplets evident at
-
31
31
equivalent P nuclei of the trimpsi ligand and the P nucleus
of the PMe ligand, while the signal at -54.0 is due to the
3
Figure 4. ORTEP diagram of (trimpsi)Ta(NO)I2(PMe3) (5) with thermal
ellipsoids at the 50% probability level.
31
third P nucleus of the trimpsi ligand. The spectrum can be
simulated by fixing the peak separation of A and B to 39.1
Hz and by setting JAB to 17.1 Hz, JAX to 34.3 Hz, and JBX
to -39.6 Hz.
Table 2. Selected Bond Lengths (Å) for (trimpsi)Nb(NO)I2(PMe3) (4)a
and (trimpsi)Ta(NO)I2(PMe3) (5)
4
5
X-ray quality crystals of 4‚(3/4)CH
2 2
Cl can be obtained
Nb(1)-I(1)
Nb(1)-I(2)
Nb(1)-P(1)
Nb(1)-P(2)
Nb(1)-P(3)
Nb(1)-P(4)
Nb(1)-N(1)
N(1)-O(1)
2.9818(5)
2.9808(5)
2.610(1)
2.610(1)
2.727(1)
2.597(1)
1.836(4)
1.239(5)
Ta(1)-I(1)
Ta(1)-I(2)
Ta(1)-P(1)
Ta(1)-P(2)
Ta(1)-P(3)
Ta(1)-P(4)
Ta(1)-N(1)
N(1)-O(1)
2.9407(5)
2.9552(6)
2.582(2)
2.593(2)
2.711(2)
2.600(2)
1.824(5)
1.264(7)
from a saturated CH Cl solution, and they have been
2
2
analyzed crystallographically. There are two independent
molecules in the asymmetric unit; the solid-state molecular
structure of one of these is shown in Figure 3. Selected bond
lengths and bond angles are collected in Tables 2 and 3,
respectively. The geometry around niobium is best described
as monocapped distorted octahedron in which the nitrosyl
ligand occupies the capping position while P(1), P(2), and
P(4) define the capped face of the octahedron and P(3), I(1),
and I(2) define the opposite face. Consistent with the IR
spectrum which indicates considerable NbfNO π-back-
bonding, the Nb(1)-N(1) bond is quite short [1.836(4) Å]
while the N(1)-O(1) bond is long [1.239(5) Å]. These values
a
For one of the independent molecules in the asymmetric unit.
which exhibits a Ta-N distance of 1.897(12) Å and an N-O
distance of 1.214(14) Å.
7
X-ray diffraction quality crystals of 5‚THF can be obtained
from a saturated THF solution. The solid-state molecular
structure of 5 is shown in Figure 4, and pertinent bond
lengths and bond angles are collected in Tables 2 and 3,
respectively. The tantalum complex exhibits the same
2
are much different than those found for (trimpsi)Nb(CO) -
4
(
5
NO), but they are comparable to those of Ta(CNAr) (NO),
Inorganic Chemistry, Vol. 41, No. 21, 2002 5391

Hayton et al.
Table 3. Selected Bond Angles (deg) for (trimpsi)Nb(NO)I2(PMe3) (4)a
and (trimpsi)Ta(NO)I2(PMe3) (5)
this fashion exists. When CH
mixture of [NO][BF
2
Cl
2
is added to an intimate
4
] and [PPN][Cl], a yellow solution
4
5
immediately results. Solution IR spectroscopy of this solution
reveals the presence of a strong ν(NO) vibration at 1847
cm , identical to that of authentic ClNO in CH Cl . When
2 2
I(1)-Nb(1)-I(2)
I(1)-Nb(1)-P(1)
I(1)-Nb(1)-P(2)
I(1)-Nb(1)-P(3)
I(1)-Nb(1)-P(4)
I(1)-Nb(1)-N(1)
I(2)-Nb(1)-P(1)
I(2)-Nb(1)-P(2)
I(2)-Nb(1)-P(3)
I(2)-Nb(1)-P(4)
I(2)-Nb(1)-N(1)
P(1)-Nb(1)-P(2)
P(1)-Nb(1)-P(3)
P(1)-Nb(1)-P(4)
P(1)-Nb(1)-N(1)
P(2)-Nb(1)-P(3)
P(2)-Nb(1)-P(4)
P(2)-Nb(1)-N(1)
P(3)-Nb(1)-P(4)
P(3)-Nb(1)-N(1)
P(4)-Nb(1)-N(1)
Nb(1)-N(1)-O(1)
94.35(1)
163.24(4)
77.22(3)
87.17(3)
76.36(3)
123.4(1)
77.96(3)
162.23(3)
86.90(3)
76.86(3)
124.7(1)
105.79(4)
77.64(4)
115.54(4)
72.6(1)
I(1)-Ta(1)-I(2)
91.02(2)
161.81(4)
79.05(4)
87.06(4)
77.06(5)
125.6(2)
78.48(5)
160.99(5)
86.74(4)
78.16(5)
126.5(2)
106.42(6)
77.63(6)
114.56(7)
72.2(2)
-1
38
I(1)-Ta(1)-P(1)
I(1)-Ta(1)-P(2)
I(1)-Ta(1)-P(3)
I(1)-Ta(1)-P(4)
I(1)-Ta(1)-N(1)
I(2)-Ta(1)-P(1)
I(2)-Ta(1)-P(2)
I(2)-Ta(1)-P(3)
I(2)-Ta(1)-P(4)
I(2)-Ta(1)-N(1)
P(1)-Ta(1)-P(2)
P(1)-Ta(1)-P(3)
P(1)-Ta(1)-P(4)
P(1)-Ta(1)-N(1)
P(2)-Ta(1)-P(3)
P(2)-Ta(1)-P(4)
P(2)-Ta(1)-N(1)
P(3)-Ta(1)-P(4)
P(3)-Ta(1)-N(1)
P(4)-Ta(1)-N(1)
Ta(1)-N(1)-O(1)
1
5
[NO][BF
4
] is replaced by [ NO][BF
4
], the IR spectrum that
-1
results has a ν(NO) peak at 1814 cm , as expected for
isotopic substitution of N with N. It may also be noted
that another route for the formation of Cl NO involves the
1
4
15
1
5
15
39
reaction of [PPN][ NO
Reactions of (trimpsi)M(CO)
with ClNO. Reaction of (trimpsi)V(CO)
2
] with 2 equiv of Bu
(NO) (M ) V, Nb, Ta)
(NO) with 1 equiv
3
SiCl.
2
2
of ClNO at -78 °C results in a color change from red to
yellow and the evolution of a gas. Solution IR spectroscopy
reveals the presence of the starting material and 1 (Scheme
77.18(4)
115.39(4)
72.4(1)
155.72(4)
129.0(1)
75.3(1)
76.68(6)
114.65(7)
71.9(2)
157.74(6)
127.3(2)
75.0(2)
1
). Addition of a further equivalent of ClNO consumes the
remaining (trimpsi)V(CO) (NO). When generated in this
fashion, 1 can be isolated from the final reaction mixture in
3% yield. Two observations suggest that the transformation
of (trimpsi)V(CO) (NO) to 1 does not proceed through a
dinitrosyl intermediate. First, when only 1 equiv of ClNO is
added to a solution of (trimpsi)V(CO) (NO), starting material
is still present in solution as determined by IR spectroscopy.
2
3
178.1(3)
179.2(6)
2
a
For one of the independent molecules in the asymmetric unit.
2
coordination geometry as the niobium congener. In this
instance P(1), P(2), and P(4) define the capped face of the
octahedron while I(1), I(2), and P(3) define the opposite face.
The Ta-N distance is 1.824(5) Å and the N-O distance is
1
5
Second, when 2 equiv of Cl NO is reacted with the
vanadium carbonyl precursor, no evidence for the incorpora-
tion of a labeled nitrosyl ligand is provided by either IR
14
15
1.264(7) Å. Again, these values are quite different from those
spectroscopy or mass spectrometry. If (trimpsi)V( NO)( -
4
determined for (trimpsi)Ta(CO)
those found in 4. The average Ta-P distance of 2.62 Å is
also similar to that extant in 4.
2
(NO), but are similar to
NO)Cl were an intermediate during the formation of 1, then
14
15
an equal distribution of (trimpsi)V( NO)Cl
NO)Cl should result, assuming a negligible isotope effect.
However, this distribution is not observed experimentally.
Reaction of (trimpsi)Nb(CO) (NO) with 1 equiv of ClNO
2
and (trimpsi)V( -
2
2
The fact that 16e (trimpsi)V(NO)I is thermally stable
under ambient conditions but the niobium and tantalum
congeners require stabilization as 18e species by coordination
of phosphine may well reflect the ability of the heavier metals
to more readily form seven-coordinate complexes. For
instance, the nitrosyl ligand in the coordinatively unsaturated
2
at -78 °C results in a color change from maroon to olive
green along with the evolution of CO (Scheme 1). An IR
spectrum of the final solution reveals the presence of two
-1
strong absorptions at 1624 and 1529 cm which are assigned
as the ν(NO) vibrations of (trimpsi)Nb(NO) Cl (6). Upon
(
trimpsi)M(NO)I
2
(M ) Nb, Ta) species may be able to bend
2
2
to an η -bonding mode which could result in cleavage of
warming the solution to room temperature, a striking color
change from green to pale orange occurs along with the
formation of a pale yellow precipitate (eq 5). An IR spectrum
3
7
the N-O bond and subsequent complex decomposition.
Alternatively, the (trimpsi)M(NO)I complexes could oligo-
2
merize via isonitrosyl bridges that then facilitate oxygen atom
transfer and subsequent decomposition. Such a process has
been invoked to account for the facile decomposition of 16e
2
Cp*Mo(Me)
2
(NO) at room temperature. Whatever the actual
decomposition pathway, it is clear that coordination of PMe
to the vacant coordination site in the (trimpsi)M(NO)I
3
2
complexes renders the compounds kinetically stable and
permits their isolation.
1
5
Synthesis of Cl NO. We have discovered that a conve-
of the supernatant solution contains no features attributable
to ν(NO) vibrations. The related (trimpsi)Ta(CO) (NO) reacts
2
15
nient procedure for the generation of Cl NO involves the
metathesis reaction of [ NO][BF ] and [PPN][Cl] (PPN )
15
4
with ClNO in the same fashion at -78 °C to give an orange
solution (Scheme 1). An IR spectrum of this solution reveals
the presence of two strong absorptions at 1605 and 1515
(
Ph
3
P)
2
N) (eq 4).
[
NO][BF ] + [PPN][Cl] f ClNO + [PPN][BF ] (4)
4
4
-1
cm which are attributed to the ν(NO) vibrations of
To our knowledge no report of ClNO being generated in
(38) Pass, G.; Sutcliffe, H. Practical Inorganic Chemistry; Chapman &
Hall: London, 1968; pp 145-146.
(39) Haub, E. K.; Lizano, A. C.; Noble, M. E. Inorg. Chem. 1995, 34,
1440-1444.
(
37) Legzdins, P.; Young, M. A. Comments Inorg. Chem. 1995, 17, 239-
254.
5392 Inorganic Chemistry, Vol. 41, No. 21, 2002

2
ReactiWities of (trimpsi)M(CO) (NO) Complexes
Scheme 1
(
trimpsi)Ta(NO)
2
Cl (7). No color change occurs upon
At first glance, the differing reactivities of the various
(trimpsi)M(CO) (NO) complexes toward ClNO are a bit
perplexing. Since ClNO is in equilibrium with Cl and NO
in solutions, our observations would seem to suggest that
(trimpsi)V(CO) (NO) reacts more rapidly with the Cl than
warming of this solution, but a pale yellow precipitate is
deposited (eq 5). Solution IR spectroscopy reveals a gradual
diminution of the ν(NO) peaks, but at a much slower rate
than that observed for 6. Regrettably, all attempts to isolate
2
2
2
2
6
and 7 have so far been unsuccessful. However, analysis
of the headspace above the two room-temperature solutions
by GC/MS reveals the presence of N O (eq 5).
The interaction of early-metal complexes with NO fre-
with the ClNO present to form 1 as the principal product.
Conversely, the niobium and tantalum congeners apparently
react preferentially with ClNO to form 6 and 7, respectively,
as the main products. Even though we have previously
observed similar chemistry with the isoelectronic Cp*M-
(CO) (NO) complexes of the group 6 elements, substantia-
2
tion of this hypothesis for the group 5 reactants requires
additional experimental investigations.
2
40,41
quently results in the formation of N
2
O.
These reactions
29
are often presumed to proceed via unobserved nitrosyl
intermediates. In this instance, however, the nitrosyl inter-
mediates are stable enough to be detected spectroscopically.
The same transformation mediated by late transition metals
also has precedents in the chemical literature.4
Summary
2-45
The oxidation of (trimpsi)V(CO)
halogenating agents such as PhICl
affords the corresponding halo complexes (trimpsi)V(NO)-
(X ) Cl, Br, I) in moderate yields. The oxidation of
trimpsi)M(CO) (NO) (M ) Nb, Ta) with 1 equiv of I at
78 °C, followed quickly by the addition of excess PMe
gives (trimpsi)M(NO)I (PMe ) in moderate to low yields.
The reaction of (trimpsi)V(CO) (NO) with 2 equiv of ClNO
produces (trimpsi)V(NO)Cl , whereas the analogous reactions
of (trimpsi)M(CO) (NO) (M ) Nb, Ta) with 1 equiv of
ClNO generate (trimpsi)M(NO) Cl species which are stable
2
(NO) with halogens and
When (trimpsi)Nb(CO)
2
(NO) is treated with 1 equiv of
at -78 °C, an olive-green solution forms.
Solution IR spectroscopy shows two ν(NO) bands at 1609
2
, Br , or I , at -78 °C
2
2
15
2 2
Cl NO in CH Cl
X
2
-1
and 1511 cm , thereby suggesting the formation of (trimpsi)-
Nb( NO)( NO)Cl. Similarly, (trimpsi)Ta( NO)( NO)Cl
(
2
2
1
4
15
14
15
-
3
,
15
and (trimpsi)Ta( NO)
fashion from (trimpsi)Ta(CO)
NO) values of 1590 and 1497 cm , and 1572 and 1481
2
Cl can be formed in an identical
2
3
2
(NO) with corresponding ν-
2
-
1
(
2
-
1
cm , respectively.
2
31
1
The P{ H} NMR spectrum of 6 generated in situ at -45
C in CD Cl shows two broad singlets at -14.6 ppm (1P)
2
°
2
2
in solution only at low temperatures.
and -31.5 ppm (2P), consistent with the proposed formula-
tion. This spectrum is similar to that exhibited by 1 for which
the resonance for the phosphine trans to the nitrosyl ligand
occurs upfield from the resonance for the phosphine trans
to the chloride. Upon warming, the resonances at -14.6 and
The availability of complexes 1-4 represents a unique
opportunity to study the chemistry of the nitrosyl ligand when
bound to an early transition metal. Specifically, the introduc-
tion of new ligands into the metals’ coordination spheres
via metathesis of the halide ligands of 1-4 may yield
interesting chemistry. This avenue of investigation will be
explored, and its results will be reported in due course.
-
31.5 ppm quickly disappear as the complex decomposes.
31
1
The room-temperature P{ H} NMR spectrum of 7 in CD
Cl consists of a triplet at -19.4 ppm (1P) and a doublet at
33.3 ppm (2P) with identical JPP coupling constants of
.1 Hz. Again, over the course of several hours at room
2
-
2
2 3
Unfortunately, the low yields of (trimpsi)Ta(NO)I (PMe )
2
-
8
will limit the development of the corresponding tantalum
system. Consequently, our future studies involving nitrosyl
complexes of this metal will focus on improving the synthesis
3
1
1
temperature these signals disappear. Finally, the P{ H}
spectrum of 7- N
pseudoquintet at -19.4 ppm (1P) and a triplet of doublets
at -33.3 ppm (2P) with JPN coupling constants of 8 and 13
15
2
2 2
at -20 °C in CD Cl consists of a
of the diiodo complex and on forming (trimpsi)Ta(NO)X
PMe ) (X ) Cl, Br), which may well be isolable in higher
yields.
Experimental Section
2
-
(
3
2
Hz.
(
(
(
40) McNeill, K.; Bergman, R. G. J. Am. Chem. Soc. 1999, 121, 8260-
269.
41) Bottomley, F.; Darkwa, J.; Sutin, L.; White, P. S. Organometallics
General Methods. All reactions and subsequent manipulations
were performed under anaerobic and anhydrous conditions either
under high vacuum or in an atmosphere of dinitrogen or argon.
General procedures routinely employed in these laboratories have
been described in detail previously.46 Tetrahydrofuran was distilled
8
1986, 5, 2165-2171.
42) Schneider, J. L.; Carrier, S. M.; Ruggiero, C. E.; Young, V. G., Jr.;
Tolman, W. B. J. Am. Chem. Soc. 1998, 120, 11408-11418.
(43) Lin, R.; Farmer, P. J. J. Am. Chem. Soc. 2001, 123, 1143-1150.
44) Franz, K. J.; Lippard, S. J. J. Am. Chem. Soc. 1999, 121, 10504-
(
10512.
(46) Legzdins, P.; Rettig, S. J.; Ross, K. J.; Batchelor, R. J.; Einstein, F.
(45) Franz, K. J.; Lippard, S. J. J. Am. Chem. Soc. 1998, 120, 9034-9040.
W. B. Organometallics 1995, 14, 5579-5587.
Inorganic Chemistry, Vol. 41, No. 21, 2002 5393

Hayton et al.
from molten potassium, while dichloromethane, 1,2-dimethoxy-
ethane (DME), and acetonitrile were distilled from calcium hydride.
gas evolution occurred, the color changed from cherry red to yellow,
and a brown precipitate formed. The final mixture was filtered
through Celite (2 cm × 2 cm) on a medium porosity frit. The
volume of the filtrate was reduced to 5 mL in vacuo, and the flask
was cooled to -30 °C overnight to induce the deposition of yellow
crystals of 1 (0.047 g, 51% yield).
PMe
activated 4 Å molecular sieves and degassed prior to use. CD
was distilled from calcium hydride, and THF-d was dried over a
potassium mirror prior to use. [NO][BF ] was purchased from
Aldrich and was purified by sublimation under dynamic vacuum
before use. The compounds (trimpsi)M(CO) (NO) (M ) V, Nb,
3
was dried over NaK prior to use, and CD
2
Cl
2
was dried over
3
CN
8
4
Method C. A red CH Cl (20 mL) solution of (trimpsi)V(CO) -
2
2
2
2
2 6
(NO) (0.102 g, 0.23 mmol) and C Cl (0.054 g, 0.23 mmol) was
4
15
47
15
2
48
Ta), [ NO][BF
4
], Diazald- N, and PhICl
2
were prepared by
refluxed for 3 h to obtain a clear yellow solution. The volume of
the solution was reduced to 5 mL in vacuo, and the flask was cooled
to -30 °C overnight to induce the deposition of yellow crystals
(0.036 g, 37% yield).
published procedures. All other reagents were used as received from
commercial sources.
NMR spectra were recorded on Bruker AMX 500, AV 300, or
1
13
AV 400 instruments. H and C spectra are referenced to external
SiMe using the residual protio solvent peaks as internal standards
H NMR) or the characteristic resonances of the solvent nuclei
Method D. To a solution of (trimpsi)V(CO)
mmol) in CH Cl (10 mL) at -78 °C was added ClNO (1.4 M
CH Cl solution, 0.35 mL, 0.49 mmol). Upon warming of the
2
(NO) (0.104 g, 0.23
4
2
2
1
(
(
2
2
13
31
31
C NMR). P spectra are referenced to external 85% H
3
PO
4
. P-
mixture, gas evolution occurred, the color changed from cherry red
to yellow, and a small amount of a white precipitate formed. The
mixture was filtered through Celite (2 cm × 2 cm) on a medium
porosity frit. The volume of the filtrate was reduced to 5 mL in
vacuo, and cooling of the flask to -30 °C overnight resulted in
the deposition of yellow crystals of 1 (0.035 g, 33% yield).
1
{
H} NMR spectra were simulated using LAOCOON. Where
appropriate, NMR spectral assignments were supported by con-
ventional homonuclear and heteronuclear correlation spectroscopy
experiments.
Headspace gas analysis was performed using a Carlo Erba Series
4
160 gas chromatograph with a Supelco Mol Sieve 5A Plot column
Preparation of (trimpsi)V(NO)Br
of (trimpsi)V(CO) (NO) (0.90 g, 2.1 mmol) in CH
78 °C was added a solution of Br (5.5 mL, 0.43 M CH
2
(2). To a stirred solution
Cl (15 mL) at
Cl
coupled to an Kratos MS80 mass spectrometer.
2
2
2
15
15
Preparation of Cl NO. To an intimate mixture of [ NO][BF
0.012 g, 0.10 mmol) and [PPN][Cl] (0.043 g, 0.08 mmol) was
added CH Cl (5 mL) via syringe. Over the course of 30 min the
4
]
-
2
2
2
(
solution, 2.4 mmol) via a fine-bore cannula. The initially cherry-
red solution became orange, and CO gas evolution occurred. The
reaction mixture was warmed to room temperature and was stirred
for an additional 20 min. The volume of the final solution was
reduced to 10 mL in vacuo, and pentane (5 mL) was syringed into
the solution. The flask was then cooled to -30 °C overnight to
induce the formation of yellow crystals which were collected by
filtration and dried under vacuum (0.92 g, 82% yield). These crystals
2
2
15
solution turned pale orange as Cl NO was formed. Unlabeled ClNO
can be prepared similarly. Solutions generated in this fashion were
usually cannulated directly into solutions of the starting material.
The presence of [PPN][BF ] in the reaction mixture did not seem
4
to affect the course of the reaction, although if needed ClNO could
be vacuum transferred into a new vessel.
Preparation of (trimpsi)V(NO)Cl
stirred solution of (trimpsi)V(CO) (NO) (2.12 g, 4.7 mmol) in CH
Cl (30 mL) at -78 °C was added a solution of PhICl (1.30 g, 4.7
mmol) in CH Cl (20 mL) via a fine-bore cannula. The initially
cherry-red solution became orange, and CO gas was evolved. The
reaction mixture was allowed to warm to room temperature and
was stirred for an additional 18 h. The volume of the final solution
was reduced to 10 mL under reduced pressure, and the flask was
then cooled to -30 °C overnight. The large mass of yellow crystals
of 1 (1.31 g, 60% yield) was collected by filtration and dried for
2
(1). Method A. To a rapidly
were recrystallized from CH
. Anal. Calcd for C13
Found: C, 28.51; H, 5.96; N, 2.50. IR (Nujol): ν(NO) 1589 (s)
2 2
Cl /hexanes to obtain analytically pure
2
2
-
2
2 3
H33Br NOP SiV: C, 28.33; H, 6.03; N, 2.54.
2
2
cm . NMR data: 1H (CDCl
.8 Hz, CH ), 0.90 (s, CMe ), 0.98 (m, 2 CH), 1.19 (d, JPH ) 6.2
Hz, PMe ), 1.21 (m, 2 CH), 1.75 (vt, JPH ) 4.4 Hz, 2 PMe), 1.86
vt, JPH ) 4.0 Hz, 2 PMe); H{ P} (CDCl
.48 (s, CH ), 0.90 (s, CMe ), 0.98 (d, JHH ) 14.7 Hz, 2 CH), 1.19
s, PMe ), 1.20 (d, JHH ) 14.7 Hz, 2 CH), 1.75 (s, 2 PMe), 1.86 (s,
-1
2
2
3
, 500 MHz, 25 °C) δ 0.48 (d, JPH )
8
2
3
2
1
31
(
3
, 500 MHz, 25 °C) δ
0
2
3
(
2
2
PMe); 13C{ H} (CDCl
1
3
, 125 MHz, 25 °C) δ 7.0 (d, JCP ) 6.4
), 15.8 (m, CMe ), 17.2 (d, JCP ) 12.5 Hz,
), 26.2 (d, JCP ) 12.9 Hz, 2 PMe), 26.3 (d,
several hours in vacuo. Anal. Calcd for C13
3
2 3
H33Cl NOP SiV: C,
3.78; H, 7.20; N, 3.03. Found: C, 33.66; H, 7.04; N, 3.05. IR
Hz, CH
PMe ), 25.6 (s, CMe
CP ) 12.9 Hz, 2 PMe); P{ H} (CDCl
br s, 1P), -1.7 (br s, 2P). MS (EI, 300 °C) m/z, 521 [P - NO].
Preparation of (trimpsi)V(NO)I as Its THF solvate (3‚THF).
To a rapidly stirred solution of (trimpsi)V(CO) (NO) (0.144 g, 0.32
mmol) in CH Cl (10 mL) at -78 °C was added a solution of I
5.0 mL, 0.06 M CH Cl solution, 0.30 mmol) via a fine-bore
2
), 8.5 (s, 2 CH
2
3
2
3
-
1
1
(Nujol): ν(NO) 1601 (s) cm . NMR data: H (CD
2
Cl
), 0.90 (s, CMe ), 0.96 (m, 2
2
), 1.22 (m, 2 CH), 1.68 (vt, JPH
2
, 500 MHz,
31
1
J
(
3
, 202 MHz, 25 °C) δ -26.1
2
5 °C) δ 0.42 (d, JPH ) 8.9 Hz, CH
2
3
+
CH), 1.03 (d, JPH ) 6.3 Hz, PMe
)
Cl
2
1
31
4.7 Hz, 2 PMe), 1.89 (vt, JPH ) 4.2 Hz, 2 PMe); H{ P} (CD
, 500 MHz, 25 °C) δ 0.42 (s, CH ), 0.90 (s, CMe ), 0.96 (d,
), 1.22 (d, JHH ) 14.7 Hz, 2
2
-
2
2
2
3
2
2
2
JHH ) 14.7 Hz, 2 CH), 1.03 (s, PMe
2
(
2
2
13
1
CH), 1.68 (s, 2 PMe), 1.89 (s, 2 PMe); C{ H} (CD
5 °C) δ 7.3 (d, JCP ) 6.3 Hz, CH ), 8.9 (s, 2 CH
PMe ), 17.1 (m, CMe
3 2 2
CP ) 12.5 Hz, 2 PMe), 25.6 (s, CMe ); P{ H} (CD Cl , 202
2 2
Cl , 125 MHz,
cannula. The initially cherry-red solution became deep purple, and
CO gas evolution occurred. The reaction mixture was warmed to
room temperature and was stirred for an additional 30 min. The
purple mixture was filtered through a plug of Celite (3 × 1 cm)
supported on a medium porosity frit which was subsequently
2
2
2
), 15.7 (m,
2
3
), 23.7 (d, JCP ) 12.5 Hz, 2 PMe), 23.9 (d,
31
1
J
MHz, 25 °C) δ -24.5 (br s, 1P), -0.1 (br s, 2P). MS (EI, 250 °C)
m/z, 431 [P - NO].
+
2 2
washed with CH Cl (10 mL). Solvent was removed from the
Method B. To a solution of (trimpsi)V(CO)
mmol) in CH Cl (20 mL) at -78 °C was added AgCl (0.113 g,
.79 mmol) via a powder funnel. Upon warming of the mixture,
2
(NO) (0.090 g, 0.20
combined filtrates in vacuo, and the solid residue was taken into
the glovebox. THF (5 mL) was pipetted onto the solid, and the
resulting purple solution was filtered into a small vial through a
plug of Celite (2 × 0.5 cm) supported by glass wool in a pipet.
Hexanes (0.5 mL) were layered on top of the THF solution, and
the vial was cooled to -35 °C overnight, whereupon a purple
powder deposited (0.068 g, 29% yield). The powder was doubly
2
2
0
(
47) Connelly, N. G.; Dragget, P. T.; Green, M.; Kuc, T. A. J. Chem. Soc.,
Dalton Trans. 1977, 70-73.
(
48) Fieser, L. F.; Fieser, M. Reagents in Organic Synthesis; Wiley: New
York, 1967; Vol. 1.
5394 Inorganic Chemistry, Vol. 41, No. 21, 2002

2
ReactiWities of (trimpsi)M(CO) (NO) Complexes
recrystallized from THF/hexanes to obtain analytically pure 3‚THF.
(s) cm-1. NMR: 1H (THF-d
0.98 (d, JPH ) 10.5 Hz, CH ), 1.04 (m, 2CH), 1.56 (br s overlapping
d, 4PMe and PMe , 21H), 1.68 (m, 2CH), 1.99 (d, JPH ) 7.0 Hz,
8 3
, 500 MHz, 25 °C) δ 0.88 (s, CMe ),
Anal. Calcd for C13 NOP SiV‚C O: C, 28.47; H, 5.76; N,
H
33
I
2
3
H
4 8
2
1
.95. Found: C, 28.43; H, 5.77; N, 1.92. IR (Nujol): ν(NO) 1607
3
s) cm . NMR data: 1H (CD
9.2 Hz, CH ), 0.93 (s, CMe
.45 (d, JPH ) 6.2 Hz, PMe ), 1.74 (vt, JPH ) 4.2 Hz, 2 PMe),
.78 (vt, JPH ) 4.4 Hz, 2 PMe); H{ P} (CD
), 0.93 (s, CMe ), 1.02 (d, JHH ) 14.5 Hz, 2
-
1
Cl
), 1.02 (m, 2 CH), 1.20 (m, 2 CH),
, 500 MHz, 25 °C) δ 0.71 (d, JPH
PMe
0.98 (s, CH
, 6H); H{ P} (THF-d
1
31
, 500 MHz, 25 °C) δ 0.88 (s, CMe
), 1.57
, 6H); 31P-
(
2
2
2
8
3
),
)
1
1
2
3
2
), 1.04 (d, JHH ) 12.0 Hz, 2CH), 1.56 (s, PMe
3
2
(s, 4PMe), 1.68 (d, JHH ) 13.7 Hz, 2CH), 1.99 (s, PMe
2
1
31
1
2
Cl
2
, 500 MHz, 25
{ H} (THF-d
8
, 202 MHz, 25 °C) δ -15.9 (m, 3P), -54.0 (m, 1P);
/C , 125 MHz, -20 °C) δ 3.6 (br s, CH ), 7.5
), 14.8 (br s, 2PMe), 15.5 (d, JPC ) 20 Hz, PMe ), 17.4
(br s, 2PMe), 24.9 (s, CMe ). Signal for one 2PMe resonance
13
°
C) δ 0.71 (s, CH
2
3
C{1H} (THF-h
(br s, 2CH
8
6
D
6
2
2
), 1.74 (s, 2
2
3
PMe), 1.78 (s, 2 PMe); 13C{ H} (CD
1
3
obscured by solvent peak at 15.8; signal for the quaternary carbon
+
of the tert-butyl was not found. MS (EI, 150 °C) m/z, 776 [P
PMe ].
Preparation of (trimpsi)Nb(NO)
solution of (trimpsi)Nb(CO)
Cl (10 mL) at -78 °C was quickly added a solution of ClNO
(0.54 M CH Cl solution, 0.85 mL, 0.46 mmol). Gas was evolved,
-
3
+
2
Cl (6). To a rapidly stirred
Preparation of (trimpsi)Nb(NO)I
stirred solution of (trimpsi)Nb(CO) NO (0.205 g, 0.42 mmol) in
CH Cl (25 mL) at -78 °C was quickly added a solution of I
0.106 g, 0.42 mmol) in CH Cl (10 mL). The initially maroon
solution became orange-brown, and CO gas was evolved. After 20
s, PMe (0.3 mL, 2.9 mmol) was added via syringe, and the stirred
2
(PMe
3
) (4). To a rapidly
2 2
(NO) (0.226 g, 0.46 mmol) in CH -
2
2
2
2
2
2
2
(
2
2
the solution quickly turned deep green, and a green powder was
deposited. The solution was separated from the powder by filter
cannulation. The green powder was dried in vacuo. All manipula-
tions of the powder were performed at temperatures below -30
°C. If the temperature was allowed to rise above 0 °C, the green
powder quickly turned brown. Due to the thermally sensitive nature
of this material, neither a combustion analysis nor a yield could be
3
solution was allowed to warm to room temperature. After being
stirred for 30 min, the solvent was removed in vacuo, the remaining
yellow-orange powder was dissolved in THF (10 mL), and the
solution was filtered through a plug of Celite (2 × 2 cm). The
Celite was rinsed with THF (5 mL), and the combined filtrates
were concentrated under reduced pressure and were layered with
hexanes (5 mL). The final mixture was cooled to -30 °C for 24 h,
whereupon 4 deposited as an analytically pure orange powder (0.207
-
1
obtained. IR (CH
2
Cl
2
): ν(NO) 1624 (s), 1529 (s) cm . NMR:
31
1
P{ H} (CD
2 2
Cl , 202 MHz, -45 °C) δ -14.6 (s, 1P), -31.5 (s,
14
15
2P). IR for (trimpsi)Nb( NO)( NO)Cl (in CH
2
2
Cl ): ν(NO) 1609
-
1
(s), 1511 (s) cm
.
g, 64% yield) Anal. Calcd for C16
H
42
2
I NNbOP
4
Si: C, 25.18; H,
Preparation of (trimpsi)Ta(NO) Cl (7). To a rapidly stirred
2
5
.55; N, 1.84. Found: C, 25.11; H, 5.08; N, 1.91. IR (KBr): ν-
solution of (trimpsi)Ta(CO) (NO) (0.213 g, 0.37 mmol) in CH Cl
2
(10 mL) at -78 °C was quickly added a solution of ClNO (0.54 M
2
2
NO) 1467 (s) cm . NMR: 1H (CD
d, JPH ) 10.3 Hz, CH ), 0.85 (s overlapping m, CMe
1H), 1.50 (vr t, 2PMe, 6H), 1.52 (vr t, 2PMe, 6H), 1.55 (d
overlapping m, JPH ) 9.0 Hz, PMe and 2CH, 11H), 1.90 (d, JPH
-
1
, 500 MHz, 25 °C) δ 0.78
and 2CH,
(
(
1
2
Cl
2
2
3
CH Cl solution, 0.90 mL, 0.47 mmol). Gas was evolved, and the
2
2
solution quickly turned orange. Addition of pentane (10 mL) by
syringe into the solution caused the deposition of an orange powder.
The solution was separated from the powder by filter cannulation,
and the powder was dried in vacuo. All manipulations of this
2
3
1
31
)
7.0 Hz, PMe
2
, 6H); H{ P} (CD
2
Cl
2
, 500 MHz, 25 °C) δ 0.78
(s, CH ), 0.85 (s overlapping d, CMe
2
3
and 2CH, 11H), 1.51 (s,
2
1
2
2
)
J
PMe), 1.52 (s, 2PMe), 1.55 (s overlapping d, PMe
3
and 2CH, 11H),
, 202 MHz, 25 °C) δ -10.1 (br s,
powder (7) were performed at temperatures below -30 °C. IR (CH -
31
1
-1
31
1
.90 (s, PMe
P), -14.7 (br s, 1P), -45.7 (br s, 1P); C{ H} (CD
5 °C) δ 4.9 (br s, CH ), 9.3 (d, JPC ) 3.0 Hz, 2CH
26.2 Hz, PMe ), 19.0 (m, 2PMe), 20.4 (m, 2PMe), 26.5 (d of t,
PC ) 14.8 Hz, 3.8 Hz, PMe ), 27.5 (s, CMe ), signal for the
2
); P{ H} (CD
2
Cl
2
2 2 2
Cl ): ν(NO) 1605 (s), 1515 (s) cm . NMR: P{ H} (CD Cl ,
13
1
2 2
Cl , 125 MHz,
202 MHz, 25 °C) δ -19.4 (t, J ) 8.1 Hz, 1P), -33.3 (d, J ) 8.1
14
15
2
2
), 16.4 (d, JPC
2 2
Hz, 2P). IR for (trimpsi)Ta( NO)( NO)Cl (in CH Cl ): ν(NO)
-
1
15
3
2 2 2
1590 (s), 1497 (s) cm . IR for (trimpsi)Ta( NO) Cl (in CH Cl ):
-
1
2
3
ν(NO) 1572 (s), 1481 (s) cm .
quaternary carbon of the tert-butyl ligand was not found. MS
X-ray Crystallography. Data collection for each structure was
carried out on a Rigaku/ADSC CCD diffractometer using graphite-
monochromated Mo KR radiation. Data collection for 1‚3CH Cl
+
(LSIMS, thioglycerol matrix, 150 °C) m/z, 687 [P - PMe
3
].
Preparation of (trimpsi)Ta(NO)I
stirred solution of (trimpsi)Ta(CO) (NO) (0.211 g, 0.37 mmol) in
CH Cl (15 mL) at -78 °C was added a solution of I (0.093 g,
.37 mmol) dissolved in CH Cl (15 mL). The initially maroon
solution became orange-brown as CO gas was evolved. After 20 s,
PMe (0.2 mL, 1.9 mmol) was added via syringe, and the stirred
2 3
(PMe ) (5). To a rapidly
2
2
2
and 4‚(3/4)CH Cl was carried out at -100 ( 1 °C, while data
2
2
2
2
2
collection for 5‚THF was done at -75 ( 1 °C.
Data for 1‚3CH Cl were collected to a maximum 2θ value of
5.9° in 0.50° oscillations with 58.0 s exposures. The solid-state
0
2
2
2
2
5
49
3
2 2
structure of 1‚3CH Cl was solved by direct methods and
expanded using Fourier techniques. The non-hydrogen atoms were
mixture was allowed to warm to room temperature. After being
stirred for 30 min, the solvent was removed in vacuo, and the
remaining powder was dissolved in THF (2 mL) and the solution
was filtered through a plug of Celite (0.5 cm × 2 cm). The orange
filtrate was then layered with hexanes (2 mL). Storage of this
mixture at -30 °C for 24 h resulted in the deposition of 5 as orange
crystals (0.015 g) and a pale yellow powder. The powder remained
suspended in the solution and could be separated from the crystalline
product by decanting of the mother liquor. Recooling the decanted
solution to -30 °C for several days provided a second crop of
crystals (0.015 g) and additional yellow powder. Total yield: 0.030
50
refined anisotropically, and hydrogen atoms were included but not
refined. The material crystallizes with three molecules of CH Cl
2 2
in the asymmetric unit. The lone nitrosyl ligand appears to be
disordered about three sites, with relative occupancies of 0.68, 0.21,
and 0.11. The two chloride ligands are distributed over the same
(
49) Altomare, A.; Burla, M. C.; Cammalli, G.; Cascarano, M.; Giacovazzo,
C.; Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.; Spagna, A. SIR97.
J. Appl. Crystallogr. 1999, 32, 115-119.
(
50) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.; de
Gelder, R.; Israel, R.; Smits, J. M. M. DIRDIF94; The DIRDIF-94
program system; Technical Report of the Crystallography Laboratory;
University of Nijmegen: Nijmegen, The Netherlands, 1994.
g, 10%. Anal. Calcd for C16
42 2 4
H I NTaOP Si: C, 22.58; H, 4.97; N,
1.65. Found: C, 23.75; H, 5.01; N, 1.54. IR (KBr): ν(NO) 1450
Inorganic Chemistry, Vol. 41, No. 21, 2002 5395

Hayton et al.
Table 4. X-ray Crystallographic Data for Complexes 1‚3CH2Cl2, 4‚(3/4)CH2Cl2, and 5‚THF
1‚3CH2Cl2
4‚(3/4)CH2Cl2
5‚THF
Crystal Data
empirical formula
crystal habit, color
crystal size (mm)
crystal system
C16H39Cl8NOP3SiV
irregular, orange
C16.75H43.5Cl1.5I2NNbOP4Si
platelet, orange
0.20 × 0.20 × 0.05
triclinic
C20H50I2NO2P4SiTa
platelet, orange
0.30 × 0.20 × 0.12
0.25 × 0.10 × 0.04
orthorhombic
orthorhombic
space group
Pna21
3308.2(3)
18.2473(7)
9.263(1)
19.573(1)
90
90
90
P1h
Pbca
6693.0(5)
14.9001(5)
19.9581(8)
22.507(2)
90
90
90
3
volume (Å )
3115.0(2)
14.2119(5)
14.5235(6)
15.5987(5)
80.438(1)
78.926(1)
89.433(2)
4
a
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
Z
4
8
fw (g/mol)
717.02
1.440
11.0
1472
826.91
1.763
27.52
1622
923.36
1.833
53.69
3568
3
Fcalcd (mg/m )
abs coeff (cm-1)
F000
radiation
Mo KR, 0.710 69 Å
Mo KR, 0.710 69 Å
Mo KR, 0.710 69 Å
Data Refinement
R1 ) 0.052, wR2 ) 0.111
b
final R indices
GOF on F
R1 ) 0.055, wR2 ) 0.090
1.07
R1 ) 0.064, wR2 ) 0.085
0.75
2
c
1.15
0.57 and -0.49
largest diff peak and hole (e Å-3)
2.56 and -2.07
1.51 and -2.05
a
Cell dimensions based on the following: 1‚3CH2Cl2, 13 912 reflections, 5.6° e 2θ e 55.9°; 4‚(3/4)CH2Cl2, 15 747 reflections, 5.6° < 2θ < 55.8°;
b
5
(
‚THF, 5847 reflections, 5.5° e 2θ e 53.5°. Number of observed reflections: 1‚3CH2Cl2, 5729 (Io > 2σIo); 4‚(3/4)CH2Cl2, 8925 (Io > 3σIo); 5‚THF, 3373
2 2 2 4 1/2
Io > 3σIo). R1: 1‚3CH2Cl2, 4‚(3/4)CH2Cl2, and 5‚THF, R1 ) ∑|(|Fo| - |Fc|)|/∑|Fo|. wR2: 1‚3CH2Cl2, wR2 ) [∑w(|Fo| - |Fc| ) /∑wFo ] ; 4‚(3/4)CH2Cl2
2 2 2 4 1/2 2 -1 2 2 -1 c 2 2 2
and 5‚THF, wR2 ) [∑(|Fo| - |Fc| ) /∑wFo ] . w: 1‚3CH2Cl2, w ) [σ Fo] ; 4‚(3/4)CH2Cl2 and 5‚THF, w ) [σ Fo ]
.
GOF ) [∑(w(Fo - Fc |) )/
1
/2
degrees of freedom]
.
three sites with relative occupancies of 0.32, 0.79, and 0.89.
Constraints were employed to make all V-Cl distances roughly
equivalent. The same was done for all V-N and N-O distances.
Lastly, the anisotropic displacement parameters for all three chloride
ligands were made equivalent, as were the anisotropic displacement
parameters of the disordered nitrosyl ligand. The final cycle of full-
matrix least-squares refinement was based on 5823 observed
reflections and 289 variable parameters.
For all three structure solutions and refinements, neutral atom
scattering factors were taken from Cromer and Waber. Anomalous
52
5
3
dispersion effects were included in Fcalc
; the values for ∆f′ and ∆f′′
5
4
were those of Creagh and McAuley. The values for the mass
55
attenuation coefficients are those of Creagh and Hubbell. All data
sets were corrected for Lorentz and polarization effects. All
calculations were performed using the teXsan56 crystallographic
software package of Molecular Structure Corporation and/or
SHELXL97.57 X-ray crystallographic data for all five complexesare
collected in Table 4, and full details of all crystallographic analyses
are provided as Supporting Information.
Data for 4‚(3/4)CH
2 2
Cl were collected to a maximum 2θ value
of 55.8° in 0.50° oscillations with 23.0 s exposures. The solid-
4
9
2 2
state structure of 4‚(3/4)CH Cl was solved by direct methods
50
and expanded using Fourier techniques. The material crystallizes
Acknowledgment. We are grateful to the Natural Sci-
ences and Engineering Research Council of Canada for
support of this work in the form of grants to P.L. and
postgraduate scholarships to T.W.H. We also thank Professor
E. E. Burnell of this department for help with the simulations
of the NMR spectra. P.L. gratefully acknowledges The
Canada Council for the Arts for the award to him of a Killam
Research Fellowship.
with two independent molecules in the asymmetric unit, in addition
to 1.5 molecules of CH Cl . One CH Cl , disordered about an
2 2 2 2
inversion center, was refined isotropically. All other non-hydrogen
atoms were refined anisotropically. Hydrogen atoms were included
but not refined. The final cycle of full-matrix least-squares
refinement was based on 12 717 observed reflections and 508
variable parameters.
For 5‚THF, the data were collected to a maximum 2θ value of
5
3.5° in 0.50° oscillations with 50.0 s exposures. The solid-state
Supporting Information Available: Listings of crystallographic
information, atomic coordinates and Beq values, anisotropic thermal
parameters, and intramolecular bond distances, angles, and torsion
angles. This material is available free of charge via the Internet at
http://pubs.acs.org.
51
structure of 5‚THF was solved by heavy-atom Patterson methods
and expanded using Fourier techniques.50 The material crystallizes
with one disordered molecule of THF in the asymmetric unit. This
THF molecule was modeled in two orientations and then left in
fixed positions. Hydrogen atoms were not included on the carbons
of the THF molecule. Other hydrogen atoms were included but
not refined. The final cycle of full-matrix least-squares refinement
was based on 6662 observed reflections and 235 variable param-
eters.
IC020340G
(
(
53) Ibers, J. A.; Hamilton, W. C. Acta Crystallogr. 1964, 17, 781-782.
54) Creagh, D. C.; McAuley, W. J. International Tables of X-ray
Crystallography; Wilson, A. J. C., Ed.; Kluwer Academic Publish-
ers: Boston, 1992; Vol. C, pp 219-222.
(
51) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.; Garcia-
Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla, C. PATTY; The
DIRDIF program system; Technical Report of the Crystallography
Laboratory; University of Nijmegen: Nijmegen, The Netherlands,
(55) Creagh, D. C.; Hubbell, J. H. International Tables for X-ray Crystal-
lography; Wilson, A. J. C., Ed.; Kluwer Academic Publishers: Boston,
1992; Vol. C, pp 200-206.
(56) teXsan; Crystal Structure Analysis Package; Molecular Structure
Corp.: The Woodlands, TX, 1985 and 1992.
1992.
(52) Cromer, D. T.; Waber, J. T. International Tables for X-ray Crystal-
lography; Kynoch Press: Birmingham, 1974; Vol. IV.
(57) Sheldrick, G. M. SHELXL97; University of G o¨ ttingen: G o¨ ttingen,
Germany, 1997.
5396 Inorganic Chemistry, Vol. 41, No. 21, 2002