Reactivity of (trimpsi)V(NO)X2 complexes (X = Cl, Br, I; trimpsi = tBuSi(CH2PMe2)3). Synthesis of the first group 5 alkyl nitrosyls

Article abstract of DOI:10.1021/om034227p

Treatment of (trimpsi)V(NO)Cl₂ (trimpsi = ^tBuSi(CH₂PMe₂)₃) in NEt₃ with 2 equiv each of p-toluic acid and Proton Sponge affords lemon yellow (trimpsi)V(NO)(η¹-O₂C-4-C₆H₄ Me)₂ (1) in 47% isolated yield. Similarly, reaction of (trimpsi)V (NO)Cl₂ with 2 equiv of AgOTf in CH₂Cl₂ provides lemon yellow (trimpsi)V(NO)(OTf)₂ (2) in a comparable yield. Alternatively, 2 can be obtained directly in 40% yield by treating CH₂Cl₂ solutions of (trimpsi)V(CO)₂(NO) at -60°C with 2 equiv of AgOTf. Likewise, both benzoyl peroxide and diphenyl disulfide are capable of oxidizing (trimpsi)V(CO)₂(NO) under similar conditions to form (trimpsi)V(NO)X₂-type complexes, namely (trimpsi)V(NO)(O₂CPh)₂ (3) and (trimpsi)V(NO) (SPh)₂ (4), respectively. The reactions of (trimpsi)V(NO) X₂ (X = Cl, Br) with Mg(CH₂SiMe₃)₂ ·x(dioxane) (either 0.5 equiv or an excess) in THF afford the orange-red alkyl complexes (trimpsi)V(NO)(CH₂SiMe₃)X (X = Cl (5), Br (6)) in reasonable yields. Other members of this family of complexes such as (trimpsi)V(NO)(CH₂CMe₃)Cl (7) (trimpsi)V(NO)(Me)Cl (8) can also be obtained by employing similar metathetical methodology, but all attempts to synthesize (trimpsi)V(NO) (alkyl)₂ complexes have to date been unsuccessful. All new complexes have been fully characterized by standard methods, and the solid-state molecular structures of 1·1.5C₆H₅Me and 5·2C₄H₈O have been established by single-crystal X-ray diffraction analyses.

Full text of DOI:10.1021/om034227p

Organometallics 2004, 23, 657-664
657
Rea ctivity of (tr im p si)V(NO)X2 Com p lexes (X ) Cl, Br , I;
t
tr im p si ) Bu Si(CH2P Me2)3). Syn th esis of th e F ir st Gr ou p
5 Alk yl Nitr osyls
Trevor W. Hayton, Brian O. Patrick, and Peter Legzdins*
Department of Chemistry, University of British Columbia, 2036 Main Mall,
Vancouver, British Columbia, Canada V6T 1Z1
Received October 9, 2003
t
Treatment of (trimpsi)V(NO)Cl2 (trimpsi ) BuSi(CH2PMe2)3) in NEt3 with 2 equiv each
of p-toluic acid and Proton Sponge affords lemon yellow (trimpsi)V(NO)(η1-O2C-4-C6H4Me)2
(1) in 47% isolated yield. Similarly, reaction of (trimpsi)V(NO)Cl2 with 2 equiv of AgOTf in
CH2Cl2 provides lemon yellow (trimpsi)V(NO)(OTf)2 (2) in a comparable yield. Alternatively,
2 can be obtained directly in 40% yield by treating CH2Cl2 solutions of (trimpsi)V(CO)2(NO)
at -60 °C with 2 equiv of AgOTf. Likewise, both benzoyl peroxide and diphenyl disulfide
are capable of oxidizing (trimpsi)V(CO)2(NO) under similar conditions to form (trimpsi)V-
(NO)X2-type complexes, namely (trimpsi)V(NO)(O2CPh)2 (3) and (trimpsi)V(NO)(SPh)2 (4),
respectively. The reactions of (trimpsi)V(NO)X2 (X ) Cl, Br) with Mg(CH2SiMe3)2‚x(dioxane)
(either 0.5 equiv or an excess) in THF afford the orange-red alkyl complexes (trimpsi)V-
(NO)(CH2SiMe3)X (X ) Cl (5), Br (6)) in reasonable yields. Other members of this family of
complexes such as (trimpsi)V(NO)(CH2CMe3)Cl (7) and (trimpsi)V(NO)(Me)Cl (8) can also
be obtained by employing similar metathetical methodology, but all attempts to synthesize
(trimpsi)V(NO)(alkyl)2 complexes have to date been unsuccessful. All new complexes have
been fully characterized by standard methods, and the solid-state molecular structures of
1‚1.5C6H5Me and 5‚2C4H8O have been established by single-crystal X-ray diffraction
analyses.
In tr od u ction
The organometallic complexes considered in this
report are formally vanadium(I) compounds. Interest-
ingly, low-valent vanadium complexes, namely those
which formally contain V(-I), V(0), or V(I), are relatively
rare. Indeed, much of the low-valent chemistry of
vanadium reported thus far has focused on the pho-
tolytic substitution of the carbonyl ligands of [V(CO)6]-
with Lewis bases to form [V(CO)6-nLn]--type com-
plexes.9,10 These complexes are formally d6 V(-I) and
are surprisingly stable, both to heat and in the presence
of moisture. For instance, the preparation of [Et4N]-
[V(CO)6] employs water as a solvent.11 As with the
V(-I) complexes, most of the V(0) complexes have the
general formula V(CO)6-nLn.12-14 Unlike their V(-I)
congeners, however, these octahedral 17e vanadium
species are all very reactive and tend to be air and
moisture sensitive. Complexes of this type are generally
formed by replacement of the carbonyl ligands in V(CO)6
with Lewis bases, transformations that proceed without
photolysis.12,14
In recent years we have been exploring the chemical
properties of 16-valence-electron Cp′M(NO)R2 complexes
(Cp′ ) Cp, Cp*; M ) Mo, W; R ) alkyl, aryl), and in the
process we have developed a very diverse chemistry of
these compounds,1,2 especially in the area of C-H bond
activation.3-5 These discoveries suggest that these or-
ganometallic nitrosyl complexes may well be employed
one day as agents for the conversion of hydrocarbon
feedstocks into industrially important compounds.6 This
exciting possibility was the original motivation for our
development of the related (trimpsi)V(NO)X2 complexes
t
(X ) Cl, Br, I; trimpsi ) BuSi(CH2PMe2)3).7,8 In this
contribution we describe our further investigations of
(trimpsi)V(NO)-containing complexes, specifically our
attempts to synthesize and characterize the first group
5 alkyl nitrosyl complexes.
* To whom correspondence should be addressed. E-mail: legzdins@
chem.ubc.ca.
(1) Pamplin, C. B.; Legzdins, P. Acc. Chem. Res. 2003, 36, 223-
233.
Vanadium(I) complexes also tend to be very reactive.
Many are thermally unstable at ambient conditions,
(2) Legzdins, P.; Veltheer, J . E. Acc. Chem. Res. 1993, 26, 41-48.
(3) Wada, K.; Pamplin, C. B.; Legzdins, P.; Patrick, B. O.; Tsyba, I.;
Bau, R. J . Am. Chem. Soc. 2003, 125, 7035-7048.
(4) Ng, S. H. K.; Adams, C. S.; Legzdins, P. J . Am. Chem. Soc. 2002,
124, 9380-9381.
(9) Mu¨ller, I.; Rehder, D. J . Organomet. Chem. 1977, 139, 293-304.
(10) Davison, A.; Ellis, J . E. J . Organomet. Chem. 1971, 31, 239-
247.
(11) Barybin, M. V.; Pomije, M. K.; Ellis, J . E. Inorg. Chim. Acta
1998, 269, 58-62.
(5) Adams, C. S.; Legzdins, P.; Tran, E. J . Am. Chem. Soc. 2001,
123, 612-624.
(12) Wells, F.; Wilkinson, G.; Motevalli, M.; Hursthouse, M. B.
Polyhedron 1987, 6, 1351-1360.
(6) Labinger, J . A.; Bercaw, J . E. Nature 2002, 417, 507-514.
(7) Hayton, T. W.; Daff, P. J .; Legzdins, P.; Patrick, B. O. Inorg.
Chem. 2002, 41, 4114-4126.
(8) Hayton, T. W.; Legzdins, P.; Patrick, B. O. Inorg. Chem. 2002,
41, 5388-5396.
(13) Ellis, J . E.; Faltynek, R. A.; Rochfort, G. L.; Stevens, R. E.; Zank,
G. A. Inorg. Chem. 1980, 19, 1082-1085.
(14) Barybin, M. V.; Young, V. G., J r.; Ellis, J . E. J . Am. Chem. Soc.
2000, 122, 4678-4691.
10.1021/om034227p CCC: $27.50 © 2004 American Chemical Society
Publication on Web 01/21/2004

658 Organometallics, Vol. 23, No. 4, 2004
Hayton et al.
even under an inert atmosphere.15-17 For instance,
hydrides such as VH(CO)4(dmpe) tend to decompose at
room temperature by releasing H2.18-20 Similarly, the
halide complexes [CpV(CO)3X]- (where X ) Cl, Br, I)
disproportionate to CpV(CO)4 and other unisolated
vanadium-containing species.21 A few vanadium(I) alkyls
such as [CpV(CO)3Me]- and VMe(CO)4(L2) (L2 ) dppe,
diars) are known,21,22 and each of these complexes can
be synthesized by adding an alkyl halide to an anionic
vanadium carbonyl complex. Metathetical routes to low-
valent vanadium alkyls are rare, since there are few
suitable halide or pseudohalide precursors, but V-Me
linkages in a Schiff-base complex have been formed in
this manner.23
Resu lts a n d Discu ssion
Syn th esis of (tr im p si)V(NO)(η1-O2C-4-C6H4Me)2
(1). Suspensions of (trimpsi)V(NO)Cl2 in NEt3 react with
2 equiv each of p-toluic acid and Proton Sponge (1,8-
bis(dimethylamino)naphthalene) to generate (trimpsi)V-
(NO)(η1-O2C-4-C6H4Me)2 (1) (eq 1). Crystallization of the
reaction residue from THF/hexanes provides 1 as a
lemon yellow solid in 47% yield.
F igu r e 1. ORTEP diagram of 1 with 50% probability
ellipsoids being shown. Selected bond lengths (Å) and
angles (deg): V1-N1 ) 1.704(6), V1-O2 ) 1.938(5), V1-
O4 ) 1.969(5), V1-P1 ) 2.594(2), V1-P2 ) 2.511(2), V1-
P3 ) 2.517(2), N1-O1 ) 1.226(8); V1-N1-O1 ) 171.1(6),
N1-V1-O2 ) 99.0(2), N1-V1-O4 ) 102.3(3), N1-V1-
P1 ) 171.6(2), N1-V1-P2 ) 90.2(2), N1-V1-P3 ) 89.0-
(2), O2-V1-O4 ) 99.0(2), O2-V1-P1 ) 86.3(2), O2-V1-
P2 ) 85.8(2), O2-V1-P3 ) 167.3(2), O4-V1-P1 ) 83.1(2),
O4-V1-P2 ) 165.6(2), O4-V1-P3 ) 88.9(2), P1-V1-P2
) 83.70(7), P1-V1-P3 ) 84.70(7), P2-V1-P3 ) 84.30(8).
1.704(6) and 1.226(8) Å, respectively. The N-O distance,
in particular, is quite long relative to those extant in
other nitrosyls24 and nicely demonstrates the strong
metalfNO back-bonding interaction that is present in
many early-transition-metal nitrosyls.
Complex 1 is both air- and moisture-sensitive; fur-
thermore, upon exposure to vacuum, yellow crystals of
1 turn light brown after a few hours. Possibly because
of this, an acceptable elemental analysis of 1 has not
been obtained. Nevertheless, a single-crystal X-ray
crystallographic analysis of 1 has established its iden-
tity. The requisite crystals of 1 were obtained from
toluene as the solvate 1‚1.5C6H5Me. An ORTEP dia-
gram of the solid-state molecular structure of 1 as it
occurs in these crystals is shown in Figure 1.
The 1H NMR spectrum of 1 in CD2Cl2 at -60 °C
exhibits signals due to the trimpsi ligand that are
similar to those of (trimpsi)V(NO)Cl2,8 thereby indicat-
ing that the low-temperature solution structure of the
complex resembles that found in the solid state (vide
1
supra). For instance, at -60 °C the H NMR spectrum
of 1 displays two virtual triplets due to the PMe2 groups
at 1.65 and 1.97 ppm which are diagnostic of the trimpsi
ligand being in a Cs-symmetric environment. In accord
In the solid state 1 possesses an η3-trimpsi ligand and
two η1-benzoato ligands. The three V-P bond lengths
are 2.594(2), 2.511(2), and 2.517(2) Å, and the linear
nitrosyl ligand exhibits V-N and N-O distances of
1
with the H NMR data, the 31P{1H} NMR spectrum of
1 in CD2Cl2 at -60 °C consists of two broad singlets at
-20.7 and -3.7 ppm in a 1:2 ratio, respectively. In
1
contrast, the room-temperature H NMR spectrum of 1
in CD2Cl2 consists of several broad peaks with no fine
structure, while the room-temperature 31P{1H} NMR
spectrum in the same solvent exhibits four broad
resonances from 24 to -23 ppm and a sharp resonance
at -54 ppm. The latter signal at -54 ppm is indicative
of an uncoordinated phosphorus atom.25 These variable-
temperature NMR data thus suggest that 1 undergoes
a structural change upon warming. In particular, the
31P{1H} NMR spectra suggest that upon warming the
trimpsi ligand in 1 changes from an η3 to an η2 bonding
mode. To maintain an octahedral coordination geometry
(15) Calderazzo, F.; De Benedetto, G. E.; Pampaloni, G.; Mo¨ssmer,
C. M.; Stra¨hle, J .; Wurst, K. J . Organomet. Chem. 1993, 451, 73-81.
(16) Calderazzo, F.; Pampaloni, G.; Pelizzi, G.; Vitali, F. Organo-
metallics 1988, 7, 1083-1092.
(17) Calderazzo, F.; Pampaloni, G.; Vitali, D. Gazz. Chim. Ital. 1981,
111, 455-458.
(18) Davison, A.; Ellis, J . E. J . Organomet. Chem. 1972, 36, 131-
136.
(19) Davison, A.; Reger, D. L. J . Organomet. Chem. 1970, 23, 491-
496.
(20) Su¨ssmilch, F.; Glo¨ckner, W.; Rehder, D. J . Organomet. Chem.
1990, 388, 95-104.
(21) Kinney, R. J .; J ones, W. D.; Bergman, R. G. J . Am. Chem. Soc.
1978, 100, 7902-7915.
(22) Ellis, J . E.; Faltynek, R. A. J . Organomet. Chem. 1975, 93, 205-
217.
(23) Reardon, D.; Conan, F.; Gambarotta, S.; Yap, G.; Wang, Q. J .
Am. Chem. Soc. 1999, 121, 9318-9325.
(24) Feltham, R. D.; Enemark, J . H. Top. Stereochem. 1981, 12, 155-
215.

First Group 5 Alkyl Nitrosyls
Organometallics, Vol. 23, No. 4, 2004 659
at the metal center, one of the benzoato ligands could
undergo a concomitant change from monodentate to
bidentate coordination (eq 2).
at 1654 and 1633 cm-1 and a ν(NO) absorption at 1592
cm-1 in its IR spectrum. Both the room-temperature 1H
and 31P{1H} NMR spectra of 3 in CD3CN reveal the
expected signals for a η3-trimpsi ligand in a Cs-sym-
metric environment, while the 1H NMR spectrum
displays the expected signals for two magnetically
equivalent benzoato ligands. Interestingly, there is no
evidence in the NMR spectra that 3 undergoes a
structural transformation analogous to that shown for
1 in eq 2, even though there is a very close structural
similarity between 1 and 3.
Syn th esis of (tr im p si)V(NO)(OTf)2 (2). The reac-
tion of (trimpsi)V(NO)Cl2 with 2 equiv of AgOTf in
CH2Cl2 affords yellow solutions of (trimpsi)V(NO)(OTf)2
(2) (eq 3). Complex 2 can be isolated in 40% yield by
(trimpsi)V(NO)Cl2 + 2AgOTf f
(trimpsi)V(NO)(OTf)2 + 2AgCl (3)
2
Similarly, refluxing a THF solution containing equimo-
lar amounts of (trimpsi)V(CO)2(NO) and diphenyl di-
sulfide for 18 h gives deep purple solutions of (trimpsi)V-
(NO)(SPh)2 (4) (eq 6).27 Crystallization from THF/
crystallization from CH2Cl2/hexanes as a lemon yellow
powder. The Nujol-mull IR spectrum of 2 exhibits a
ν(NO) value of 1642 (s) cm-1, approximately 50 cm-1
higher than those displayed by (trimpsi)V(NO)X2 (X )
Cl, Br, I), a feature reflecting the strongly electron-
withdrawing nature of the triflate ligand. As expected,
1
the room-temperature H NMR spectrum of 2 in CD2-
Cl2 is similar to that of (trimpsi)V(NO)Cl2 and indicates
the presence of an η3-trimpsi ligand, while its room-
temperature 19F{1H} NMR spectrum in CD2Cl2 exhibits
the anticipated singlet at -77 ppm.
Alternatively, 2 can be obtained directly from (trimpsi)-
V(CO)2(NO). Thus, 2 equiv of AgOTf reacts with CH2-
Cl2 solutions of (trimpsi)V(CO)2(NO) at -60 °C to
generate yellow solutions of 2 with the concomitant
evolution of CO (eq 4). When it is synthesized from
hexanes (1:1) provides deep red crystals of 4 as a THF
solvate in 29% yield. Complex 4 exhibits a ν(NO) band
at 1570 cm-1 in its IR spectrum as a KBr pellet, while
its 1H NMR spectrum in C6D6 contains resonances
attributable to trimpsi and to two phenyl sulfide ligands.
Having established that the oxidation of (trimpsi)V-
(CO)2(NO) with benzoyl peroxide or diphenyl disulfide
gives tractable (trimpsi)V(NO)X2-type products, we next
attempted the formation of the congeneric Nb and Ta
species in a similar manner. Disappointingly, (trimpsi)M-
(NO)X2 (M ) Nb, Ta, X ) pseudohalide) complexes do
not result from reactions analogous to those portrayed
for vanadium in eqs 5 and 6 (see Experimental Section
for details).
Syn t h eses of (t r im p si)V(NO)(R )X Com p lexes
(X ) Cl, Br ; R ) Me, CH2SiMe3, CH2CMe3). The
reactions of (trimpsi)V(NO)X2 (X ) Cl, Br) with Mg(CH2-
SiMe3)2‚x(dioxane) (either 0.5 equiv or an excess) in THF
at low temperature, followed by warming to ambient
temperatures, generate orange solutions containing
(trimpsi)V(NO)(CH2SiMe3)X (X ) Cl (5), Br (6)) (eq 7).
Crystallization from THF/hexanes affords the alkyl
complexes as orange-red crystals in reasonable yields
(5, 50%; 6, 48%). Compounds 5 and 6 represent the first
(trimpsi)V(CO)2(NO) + 2AgOTf f
(trimpsi)V(NO)(OTf)2 + 2Ag + 2CO (4)
2
(trimpsi)V(CO)2(NO) in this manner, analytically pure
2 can be isolated in 40% yield. Even though conversions
3 and 4 afford 2 in identical isolated yields, the forma-
tion of 2 by reaction 4 is more efficient than its
formation by reaction 3, since the synthesis and puri-
fication of (trimpsi)V(NO)Cl2 can be completely avoided.
Rea ction s of (tr im p si)M(CO)2(NO) (M ) V, Nb,
Ta ) w ith Ben zoyl P er oxid e a n d Dip h en yl Disu l-
fid e. Like AgOTf, both benzoyl peroxide and diphenyl
disulfide are capable of oxidizing (trimpsi)V(CO)2(NO)
to form (trimpsi)V(NO)X2-type complexes. For instance,
solutions of (trimpsi)V(CO)2(NO) in CH2Cl2 react with
1 equiv of benzoyl peroxide at -60 °C to generate yellow
(trimpsi)V(NO)(η1-O2CPh)2 (3) with concomitant evolu-
tion of CO (eq 5).26 Crystallization of the reaction
residue from toluene affords 3 as yellow crystals in 41%
yield. Complex 3 as a KBr pellet exhibits ν(CO) peaks
(25) Gardner, T. G. Ph.D. Dissertation, University of Illinois at
Urbana-Champaign, Urbana, IL, 1989.
(26) Albano, V. G.; Monari, M.; Orabona, I.; Panunzi, A.; Roviello,
G.; Ruffo, F. Organometallics 2003, 22, 1223-1230.
(27) Hessen, B.; Meetsma, A.; Teuben, J . H. J . Am. Chem. Soc. 1988,
110, 4860-4861.

660 Organometallics, Vol. 23, No. 4, 2004
Hayton et al.
isolated group 5 alkyl nitrosyl complexes. These orange
crystalline materials are soluble in Et2O, toluene, THF,
and CH2Cl2, and both are thermally stable in the solid
state and in solutions for indefinite periods of time. Both
5 and 6 have nitrosyl-stretching absorptions at ca. 1550
cm-1 in their Nujol-mull IR spectra; these features are
lower in energy than those of their parent halo com-
plexes. The room-temperature 1H NMR and 31P{1H}
NMR spectra of both 5 and 6 are consistent with the
proposed formulation and expected C1 molecular sym-
1
metry. Thus, their H NMR spectra reveal six doublets
attributable to the six inequivalent methyl groups of the
trimpsi ligand, while their 31P{1H} NMR spectra each
consist of three broad singlets. The R carbon signals for
the Me3SiCH2 ligands in the room-temperature 13C{1H}
NMR spectra occur as broad singlets at 72.9 and 77.9
ppm for 5 and 6, respectively.
F igu r e 2. ORTEP diagram of 5 with 50% probability
ellipsoids being shown. Selected bond lengths (Å) and
angles (deg): V1-P1 ) 2.533(2), V1-P2 ) 2.546(2), V1-
P3 ) 2.604(2), V1-N1 ) 1.755(8), V1-Cl ) 2.364(2), V1-
C14 ) 2.123(7), N1-O1 ) 1.117(8); Cl-V1-P1 ) 167.86(9),
Cl-V1-P2 ) 89.57(7), Cl-V1-P3 ) 86.13(8), Cl-V1-N1
) 99.8(2), Cl-V1-C14 ) 106.3(2), P1-V1-P2 ) 83.28(6),
P1-V1-P3 ) 83.47(7), P1-V1-N1 ) 90.0(2), P1-V1-C14
) 80.3(2), P2-V1-P3 ) 84.79(7), P2-V1-N1 ) 89.9(2),
P2-V1-C14 ) 163.4(2), P3-V1-N1 ) 172.0(2), P3-V1-
C14 ) 91.3(2), N1-V1-C14 ) 92.1(3), V1-N1-O1 )
174.1(6).
Crystals of 5 suitable for X-ray diffraction analysis
have been obtained from saturated THF solutions as
the solvate 5‚2THF. The solid-state molecular structure
of 5 as it occurs in these crystals is shown in Figure 2.
Complex 5 contains a linear nitrosyl ligand with V1-
N1 and N1-O1 distances of 1.755(8) and 1.117(8) Å,
respectively. The V1-C14 distance of 2.123(7) Å is
comparable to other vanadium(I) V-C single-bond
lengths.23 The three vanadium-phosphorus distances
give an indication of the π-acceptor ability of the trimpsi
ligand. For instance, the phosphorus atom trans to the
nitrosyl ligand, P3, exhibits the longest bond to vana-
dium (2.604(2) Å vs 2.533(2) and 2.546(2) Å for the V-P
bonds trans to the chloro and the alkyl ligands, respec-
tively). This is as expected, since NO is a much better
π-acceptor, and the trimpsi ligand cannot compete
efficiently for the available electron density. Consis-
tently, the phosphorus atom trans to the π-donating
chloro ligand, P1, exhibits the shortest bond to vana-
dium.28
while its 1H and 31P{1H} NMR spectra are similar to
those exhibited by 5 and 6. The signal due to the R
carbon of the CH2CMe3 ligand in 7 occurs at 110 ppm
in its 13C{1H} NMR spectrum.
In a similar manner, the reaction of (trimpsi)V(NO)-
Cl2 with 0.5 equiv of MgMe2‚x(dioxane) in THF gener-
ates a yellow solution containing (trimpsi)V(NO)(Me)Cl
(8) (eq 9). Complex 8 may be obtained analytically pure
(trimpsi)V(NO)Cl2 + 0.5MgMe2·x(dioxane) f
(trimpsi)V(NO)(Me)Cl + 0.5MgCl2·x(dioxane) (9)
8
by crystallization from THF/hexanes in 25% yield.
Again, the spectroscopic properties of 8 are similar to
those exhibited by the other monoalkyl complexes. The
signal due to the carbon atom of the methyl ligand in 8
appears as a broad singlet at 60.5 ppm in its 13C{1H}
NMR spectrum (CD2Cl2), while in the 1H NMR spec-
trum the resonance attributable to the methyl protons
occurs at 1.94 ppm as a doublet of triplets. This latter
signal collapses to a singlet in the 1H{31P} NMR
spectrum.
Attempts to prepare the bromo analogue, (trimpsi)-
V(NO)(Me)Br, by utilizing the same methodology em-
ployed for the synthesis of 8 have so far failed. 1H NMR
spectroscopy of the final reaction mixture shows that
small amounts of (trimpsi)V(NO)(Me)Br are formed in
the reaction between (trimpsi)V(NO)Br2 and MgMe2‚
x(dioxane). However, it is a minor constituent of any
Other alkyl nitrosyl complexes in this family can also
be prepared by metathetical methods. For instance, the
reaction of (trimpsi)V(NO)Cl2 with 0.5 equiv of Mg(CH2-
CMe3)2‚x(dioxane) in THF generates a red-purple solu-
tion of (trimpsi)V(NO)(CH2CMe3)Cl (7) (eq 8). Complex
(trimpsi)V(NO)Cl2 +
0.5Mg(CH2CMe3)2·x(dioxane) f
(trimpsi)V(NO)(CH2CMe3)Cl + 0.5MgCl2·x(dioxane)
7
(8)
7 can be isolated analytically pure from THF/hexanes
solutions in 30% yield. It displays an NO-stretching
frequency at 1530 cm-1 in its Nujol-mull IR spectrum,
(28) Coe, B. J .; Glenwright, S. J . Coord. Chem. Rev. 2000, 203, 5-80.

First Group 5 Alkyl Nitrosyls
Organometallics, Vol. 23, No. 4, 2004 661
isolated material, and it cannot be separated from the
other products.
these crystals, typically isolable in 14% yield based on
vanadium, to be [(η3-trimpsiO3)(η2-trimpsiO3)VO][I3]2‚
CH2Cl2‚H2O (trimpsiO3 ) tBuSi(CH2P(O)Me2)3) (9‚CH2-
Cl2‚H2O), a product of the decomposition of (trimpsi)V-
(NO)I2 by air and water.29 Full details of the isolation
and characterization of this complex are provided in the
Supporting Information.
Attem p ted Syn th eses of (tr im p si)V(NO)R2 (R )
Alk yl) Com p lexes. Given our success with the prepa-
ration of the monoalkyl complexes, (trimpsi)V(NO)(R)X
(X ) Cl, Br), we next turned our attention to the
synthesis of the bis(alkyl) complexes, (trimpsi)V(NO)-
R2, the original target molecules of this research. The
first synthetic attempts simply consisted of treating the
dihalo precursors, (trimpsi)V(NO)X2 (X ) Cl, Br), with
1.0 equiv of MgR2‚x(dioxane) (i.e. 2.0 equiv of R-). The
reactions of (trimpsi)V(NO)Cl2 or (trimpsi)V(NO)Br2
with 1.0 equiv of Mg(CH2SiMe3)2‚x(dioxane) afford 5 and
6, respectively, as the only isolable products, and an
additional metathesis event to form (trimpsi)V(NO)-
(CH2SiMe3)2 is not observed. In contrast, if (trimpsi)V-
(NO)Cl2 is reacted with 1.0 equiv of Mg(CH2CMe3)2‚
x(dioxane) in THF, the reaction mixture quickly turns
yellow-brown. The IR spectrum of the final reaction
mixture is devoid of a ν(NO) absorption, and no tractable
products can be isolated. The reaction of (trimpsi)V(NO)-
Cl2 with 1.0 equiv of MgMe2‚x(dioxane) proceeds simi-
larly.
Su m m a r y
The preparation and isolation of the complexes
(trimpsi)V(NO)(η1-O2C-4-C6H4R)2 (R ) H, Me), (trimpsi)-
V(NO)(OTf)2, (trimpsi)V(NO)(SPh)2, and (trimpsi)V-
(NO)R(Cl) (R ) CH2SiMe3, CH2CMe3, Me) demonstrate
that the (trimpsi)V(NO) fragment is thermally stable
when bound to a variety of coligands. However, several
attempts to isolate the corresponding bis(alkyl) com-
plexes, (trimpsi)V(NO)R2, have not been successful.
There may be several plausible reasons for this fact. One
possibility is that bis(alkyl) complexes are formed
initially, but they then undergo facile R-H elimination
to form (trimpsi)V(NO)(dCHR) and RCH3, a process
followed by decomposition of the alkylidene complex.
Such R-H elimination occurs readily in Cp*W(NO)R2
(R ) alkyl) complexes.5 Another possible explanation
is that the vanadium center in a bis(alkyl) complex is
simply too electron rich. That (trimpsi)V(NO)(CH2-
SiMe3)Cl (5) and the other mono(alkyl) species are
already quite electron rich is indicated by their low
ν(NO) values evident in their IR spectra. The bis(alkyl)
complexes would be even more electron rich. A concomi-
tant increase in electron density onto the nitrosyl ligand
by VfNO π-back-donation would further weaken the
N-O bond and might result in these complexes under-
going nitrosyl-ligand cleavage, a process for which there
is literature precedent.30
Attempted alkylation of (trimpsi)V(NO)(OTf)2 (2) with
1.0 equiv of Mg(CH2SiMe3)2‚x(dioxane) results in the
formation of a red-brown solution whose IR spectrum
is devoid of ν(NO) absorptions. Similar reactions be-
tween 2 and Mg(CH2CMe3)2‚x(dioxane) or MgMe2‚
x(dioxane) also fail to generate tractable nitrosyl-
containing species. The reaction of (trimpsi)V(NO)-
(CH2SiMe3)Cl (5) with 1.0 equiv of AgOTf in CH2Cl2, in
an attempt to form (trimpsi)V(NO)(CH2SiMe3)(OTf),
leads only to the isolation of 2 in very low yields.
The addition of 1.0 equiv of (Me3SiCH2)Li to a THF
solution of 5 at -30 °C results in the formation of an
orange-brown solution. An IR spectrum of this solution
reveals a single ν(NO) band at 1524 cm-1. However,
even at -30 °C, the intensity of this absorption dimin-
ishes with time, and the attempted isolation of this
material by crystallization only produces an intractable
red-brown precipitate. Similarly, the reaction of 5 with
1.0 equiv of MeLi generates a yellow solution which
exhibits a ν(NO) absorption at 1526 cm-1 in its IR
spectrum. On standing at -30 °C, though, the solution
turns orange, and no tractable material has yet been
isolated from it. It thus appears that the initial products
from the reactions between 5 and alkyllithium salts are
indeed nitrosyl-containing complexes, but they are
thermally unstable even at low temperatures and can-
not be isolated. It is not yet known whether these initial
products are in fact bis(alkyl) complexes.
Future studies with these systems will be directed
toward the synthesis of alkoxide and amide complexes
containing the (trimpsi)V(NO) fragment. In addition, the
reactivity of the vanadium-carbon bonds in the mono-
(alkyl) complexes toward unsaturated organic mol-
ecules, CO, and isocyanides will also be explored.
Exp er im en ta l Section
Gen er a l Meth od s. All reactions and subsequent manipula-
tions were performed under anaerobic and anhydrous condi-
tions either under high vacuum or under an atmosphere of
dinitrogen or argon. Pentane, hexanes, toluene, and benzene-
d6 were dried and distilled from sodium or sodium/benzophe-
none ketyl. Tetrahydrofuran was distilled from molten potas-
sium, and dichloromethane was distilled from calcium hydride.
Both CD3CN and CD2Cl2 were dried by standing over activated
4 Å molecular sieves for 2 days and degassed prior to use. Mg-
(CH2SiMe3)2‚x(dioxane),31,32 Mg(CH2CMe3)2‚x(dioxane),5 MgMe2‚
x(dioxane),30 (trimpsi)V(NO)X2 (X ) Cl, Br, I),8 and (trimpsi)M-
(CO)2(NO) (M ) V, Nb, Ta)7 were prepared by published
procedures. All other reagents were purchased from com-
mercial suppliers and were used as received.
In a further attempt to form the desired bis(alkyl)
complexes, the reaction between 5 and K(CH2SiMe3) has
been effected, but again no identifiable material could
be isolated. Finally, attempts to form a bis(methyl)
complex by reacting (trimpsi)V(NO)Cl2 with ZnMe2 only
result in the formation of mixtures of starting material
and 8.
NMR spectra were recorded on Bruker AMX 500, AVA 300,
or AVA 400 instruments. 1H and 13C spectra are referenced to
(29) Legzdins, P.; Lundmark, P. J .; Phillips, E. C.; Rettig, S. J .;
Veltheer, J . E. Organometallics 1992, 11, 2991-3003.
(30) Sharp, W. B.; Daff, P. J .; McNeil, W. S.; Legzdins, P. J . Am.
Chem. Soc. 2001, 123, 6272-6282.
Rea ction of (tr im p si)V(NO)I2 w ith H2O a n d O2.
During the initial synthesis and characterization of
(trimpsi)V(NO)I2,8 a CH2Cl2 solution of this compound
was allowed to stand at -30 °C for several months,
during which time several large orange-red crystals
formed. An X-ray crystallographic analysis has revealed
(31) Andersen, R. A.; Wilkinson, G. Inorg. Synth. 1979, 19, 262-
265.
(32) Andersen, R. A.; Wilkinson, G. J . Chem. Soc., Dalton Trans.
1977, 809-811.

662 Organometallics, Vol. 23, No. 4, 2004
Hayton et al.
external SiMe4 using the residual protio solvent peaks as
internal standards (1H NMR experiments) or the characteristic
resonances of the solvent nuclei (13C NMR experiments). 31P
spectra are referenced to external 85% H3PO4, while 19F
spectra are referenced to external trifluoroacetic acid. Where
appropriate, NMR spectral assignments were supported by
conventional homonuclear and heteronuclear correlation spec-
troscopy experiments. IR spectra were recorded on a BOMEM
MB-100 FT-IR spectrometer or a Mattson Genesis FT-IR
spectrometer. Elemental analyses were performed by Mr. M.
Lakha of this department.
10.7 (s, 2 CH2), 15.3 (d, J CP ) 12.5 Hz, PMe2), 16.7 (br s, 2
PMe), 18.6 (br s, CMe3), 20.2 (t, J CP ) 10.0 Hz, 2 PMe), 27.0
(s, CMe3). 31P{1H} NMR (CD2Cl2, 202 MHz, 25 °C): δ -21.2
(br s, 1P), 3.0 (br s, 2P). 19F NMR (CD2Cl2, 282 MHz, 25 °C):
δ -77.6 (s). MS (EI, 150 °C; m/z): 659 [P+ - NO].
Meth od B. To a solution of (trimpsi)V(CO)2(NO) (0.79 g,
1.76 mmol) in CH2Cl2 (60 mL) at -60 °C was added powdered
AgSO3CF3 (AgOTf, 0.91 g, 3.54 mmol). The stirred mixture
was warmed to room temperature while being shielded from
light. The mixture was then refluxed for 2 h, and the brown
precipitate was separated from the yellow solution by filtration
through Celite (2 cm × 2 cm) supported on a medium-porosity
frit. The filtrate was reduced to 30 mL in vacuo, hexanes (10
mL) were added, and the mixture was cooled to -30 °C
overnight to induce the precipitation of 2 as a yellow powder
which was collected and dried under vacuum (0.48 g, 40%
yield). This powder was recrystallized from CH2Cl2 to obtain
analytically pure material.
P r ep a r a tion of (tr im p si)V(NO)(η1-O2C-4-C6H4Me)2 (1).
NEt3 (15 mL) was cannulated onto an intimate mixture of
(trimpsi)V(NO)Cl2 (0.077 g, 0.17 mmol), p-toluic acid (0.045
g, 0.33 mmol), and Proton Sponge (0.071 g, 0.33 mmol). The
resulting yellow suspension was stirred at ambient tempera-
tures for 4 days. The still yellow suspension was then taken
to dryness in vacuo, and the remaining solid was dissolved in
toluene (15 mL). The yellow solution was filtered through a
plug of Celite (2 × 2 cm) supported on a medium-porosity frit,
which was subsequently washed with toluene (10 mL). The
combined yellow filtrates were taken to dryness in vacuo, and
the remaining solid was dissolved in THF (2 mL) and layered
with hexanes (3 mL). The solution was cooled overnight at -35
°C, resulting in the deposition of lemon yellow crystals of 1
(36 mg). A second crop of crystals (16 mg) was obtained by
further cooling of the solution to -35 °C overnight. Total
P r ep a r a tion of (tr im p si)V(NO)(η1-O2CP h )2 (3). A solu-
tion of (PhCO2)2 (0.047 g, 0.19 mmol) dissolved in CH2Cl2 (10
mL) was slowly added to a solution of (trimpsi)V(CO)2(NO)
(0.087 g, 0.19 mmol) in CH2Cl2 (10 mL) cooled to -60 °C,
whereupon the color changed from red to yellow. The solution
was allowed to warm to room temperature, and all the volatiles
were removed in vacuo. The resulting brown-yellow oil was
dissolved in toluene (3 mL), and this solution was filtered
though a plug of Celite (2 × 0.5 cm) supported on glass wool.
The volume of the resulting yellow-orange filtrate was reduced
to 2 mL in vacuo, and this solution was cooled to -30 °C for
several weeks to induce the deposition of yellow crystals of 3
(0.049 g, 41%). Anal. Calcd for C27H43NO5P3SiV: C, 51.18; H,
6.84; N, 2.21. Found: C, 51.24; H, 6.80; N, 2.52. IR (KBr):
yield: 52 mg (47%). IR (Nujol mull): ν(NO) 1585 (s) cm-1
,
1
ν(CO) 1645 (s) cm-1. H NMR (CD2Cl2, 500 MHz, -60 °C): δ
0.43 (d, J PH ) 9.3 Hz, CH2), 0.84 (s, CMe3), 0.94 (m, 2 CH),
1.06 (d, J PH ) 5.7 Hz, PMe2), 1.16 (m, 2 CH), 1.65 (vt, J PH
)
3.2 Hz, 2 PMe), 1.97 (vt, J PH ) 3.3 Hz, 2 PMe), 2.34 (s, 2 Me),
7.14 (d, J HH ) 7.9 Hz, 4 CH), 7.99 (d, J HH ) 7.9 Hz, 4 CH).
1H{31P} NMR (CD2Cl2, 500 MHz, -60 °C): δ 0.43 (s, CH2),
0.84 (s, CMe3), 0.95 (d, J HH ) 14.7 Hz, 2 CH), 1.07 (s, PMe2),
1.16 (d, J HH ) 12.4 Hz, 2 CH), 1.65 (s, 2 PMe), 1.97 (s, 2 PMe),
2.34 (s, 2 Me), 7.14 (d, J HH ) 7.7 Hz, 4 CH), 7.99 (d, J HH ) 7.8
Hz, 4 CH). 13C{1H} NMR (CD2Cl2, 125 MHz, -60 °C): δ 5.0
(d, J CP ) 6.7 Hz, CH2), 7.7 (s, 2 CH2), 14.0 (d, J CP ) 7.6 Hz,
PMe2), 14.4 (m, 2 PMe), 16.6 (q, J CP ) 5.6 Hz, CMe3), 18.9 (t,
J CP ) 11.1, 2 PMe), 21.2 (s, 2 Me), 24.9 (s, CMe3), 128.3 (s, 4
CH), 129.7 (s, 4 CH), 132.0 (s, CMe), 141.1 (s, O2CC), 173.1
(d, J CP ) 6.3 Hz, O2CC). 31P{1H} NMR (CD2Cl2, 202 MHz, -60
°C): δ -20.7 (br s, 1P), -3.7 (br s, 2P). 31P{1H} NMR (CD2Cl2,
202 MHz, 25 °C): δ 24.5 (br s), -4.3 (br s), -17.3 (br s), -23.1
(br s), -53.9 (s). MS (EI; m/z): 631 [P+ - NO]. High-resolution
MS (EI; m/z): found, 631.189 99; calcd for C29H47O4SiP3V,
631.189 62. Crystals of 1 suitable for an X-ray crystallographic
analysis were obtained from toluene as the solvate 1‚1.5C6H5-
Me.
1
ν(CO) (s) 1654, (s) 1633 cm-1; ν(NO) (s) 1592 cm-1. H NMR
(CD3CN, 500 MHz, 25 °C): δ 0.54 (d, J PH ) 9.4 Hz, CH2P),
0.90 (s, SiCMe3), 1.05 (d, J PH ) 5.1 Hz, PMe2), 1.13 (m, 2CH),
1.31 (m, 2CH), 1.70 (vt, 2PMe), 1.98 (vt, 2PMe), 7.31 (t, J HH
)
7.3 Hz, CHp), 7.43 (t, J HH ) 6.7 Hz, CHm), 8.15 (d, J HH ) 7.2,
CHo). 1H{13P} NMR (CD3CN, 300 MHz, 25 °C): δ 0.54 (s,
CH2P), 0.91 (s, SiCMe3), 1.06 (s, PMe2), 1.13 (d, J HH ) 14.9
Hz, 2CH), 1.35 (d, J HH ) 14.7 Hz, 2CH), 1.70 (s, 2PMe), 1.98
(s, 2PMe), 7.28 (t, J HH ) 7.9 Hz, CHp), 7.45 (t, J HH ) 7.4 Hz,
CHm), 8.18 (d, J HH ) 7.1, CHo). 13C{1H} NMR (CD3CN, 125
MHz, 25 °C): δ 5.84 (m, CH2P), 9.13 (br s, 2CH), 14.3 (m,
PMe2), 15.3 (m, 2PMe), 17.5 (m, SiCMe3), 19.8 (m,2PMe), 26.0
(s, SiCMe3), 128.9 (CHp), 130.9 (CHo), 131.8 (CHm). 31P{1H}
NMR (CD3CN, 121 MHz, 25 °C): δ -2.4 (br s, 2P), -21.5 (br
s, 1P). MS (EI, 200 °C; m/z): 603 [P+ - NO].
P r ep a r a tion of (tr im p si)V(NO)(SP h )2 (4). A solution of
(trimpsi)V(CO)2(NO) (0.106 g, 0.23 mmol) and PhSSPh (0.052
g, 0.24 mmol) in THF (15 mL) was refluxed for 18 h,
whereupon the color of the mixture changed from cherry red
to purple. The THF was removed in vacuo, and the residue
was dissolved in toluene (5 mL). This solution was filtered
though Celite (2 × 0.5 cm) supported on glass wool. The filtrate
was reduced in vacuo to 3 mL, and it was then cooled to -30
°C overnight to induce the deposition of a purple powder. This
powder was recrystallized from THF/hexanes (1:1) to obtain
P r ep a r a tion of (tr im p si)V(NO)(OTf)2 (2). Meth od A. To
an intimate mixture of (trimpsi)V(NO)Cl2 (0.105 g, 0.23 mmol)
and AgSO3CF3 (AgOTf, 0.118 g, 0.46 mmol) was added CH2-
Cl2 (15 mL) via a syringe. The suspension was shielded from
light and was stirred at ambient temperatures for 9 days. The
mixture was then filtered through Celite (2 cm × 2 cm)
supported on
a medium-porosity frit to obtain a yellow
solution. The volume of this solution was reduced to 5 mL in
vacuo, and it was then cooled to -30 °C overnight to induce
the precipitation of a yellow powder. This powder was collected
by filtration and was dried under vacuum to obtain analytically
pure 2 (0.063 g, 40% yield). Anal. Calcd for C15H33F6NO7P3S2-
SiV: C, 26.13; H, 4.82; N, 2.03. Found: C, 26.20; H, 4.82; N,
deep red crystals of 4 (0.45 g, 29%). Anal. Calcd for C25H43-
NOP3S2SiV‚C4H8O: C, 51.09; H, 7.54; N, 2.05. Found: C,
50.85; H, 7.52; N, 2.49. IR (KBr): ν(NO) 1570 (s) cm-1. 1H NMR
(C6D6, 500 MHz, 25 °C): δ 0.22 (m, 4CH), 0.56 (s, SiCMe3),
0.83 (d, J PH ) 12.8 Hz, CH2P), 1.11 (vt, 2PMe), 1.26 (d, J PH
)
5.6 Hz, PMe2), 1.42 (vt, 2PMe), 7.01 (t, J HH ) 8.9 Hz, CHp),
1
1
1.92. IR (Nujol mull): ν(NO) 1642 (s) cm-1. H NMR (CD2Cl2,
7.31 (t, J HH ) 7.6 Hz, CHm), 8.19 (d, J HH ) 7.0 Hz, CHo). H-
300 MHz, 25 °C): δ 0.27 (d, J PH ) 10.5 Hz, CH2), 0.82 (d,
J PH ) 6.5 Hz, PMe2), 0.93 (s, CMe3), 1.08 (m, 2 CH), 1.46 (m,
2 CH), 1.78 (vt, J PH ) 4.6 Hz, 2 PMe), 2.19 (vt, J PH ) 4.4 Hz,
2 PMe). 1H{31P} NMR (CD2Cl2, 500 MHz, 25 °C): δ 0.27 (s,
CH2), 0.82 (s, PMe2), 0.93 (s, CMe3), 1.08 (d, J HH ) 9.0 Hz, 2
CH), 1.46 (d, J HH ) 9.0 Hz, 2 CH), 1.78 (s, 2 PMe), 2.19 (s, 2
PMe). 13C{1H} NMR (CD2Cl2, 125 MHz, 25 °C): δ 7.3 (s, CH2),
{31P} NMR (C6D6, 500 MHz, 25 °C): δ 0.21 (overlapping d,
4CH), 0.56 (s, SiCMe3), 0.83 (s, CH2P), 1.11 (s, 2PMe), 1.26 (s,
PMe2), 1.42 (s, 2PMe), 7.01 (t, J HH ) 8.9 Hz, CHp), 7.31 (t,
J HH ) 7.6 Hz, CHm), 8.19 (d, J HH ) 7.0 Hz, CHo). 13C{1H} NMR
(C6D6, 125 MHz, 25 °C): δ 9.2 (m, 2CH), 15.4 (m, 2PMe), 16.6
(m, CH2P), 17.3 (d of t, J CP ) 11.3, 2.3 Hz, PMe2), 25.3 (m,
2PMe), 25.5 (s, SiCMe3), 124.0 (CHp), 128.0 (CHm), 133.4 (CHo).

First Group 5 Alkyl Nitrosyls
Organometallics, Vol. 23, No. 4, 2004 663
31P{1H} NMR (C6D6, 202 MHz, 25 °C): δ -10.3 (br s, 2P),
-20.9 (br s, 1P). MS (EI, 200 °C; m/z): 609 [P+].
crystals. These crystals (0.104 g) were collected by filtration
and dried in vacuo. The supernatant solution was taken to
dryness in vacuo, the remaining orange powder was dissolved
in THF (5 mL), and the resulting solution was cooled to -30
°C overnight. These operations resulted in the deposition of
additional orange crystals (0.302 g). The total yield of 6 was
0.406 g (48%). Anal. Calcd for C17H44BrNOP3Si2V: C, 36.56;
H, 7.94; N, 2.51. Found: C, 36.60; H, 7.82; N, 2.56. IR (Nujol
Rea ction s of (tr im p si)M(CO)2(NO) (M ) Nb, Ta ) w ith
Ben zoyl P er oxid e a n d Dip h en yl Disu lfid e. A THF solution
of (trimpsi)Nb(CO)2(NO) quickly reacts with 1 equiv of benzoyl
peroxide at -30 °C, and a gas is evolved. Monitoring of the
reaction by IR spectroscopy reveals the quick diminution of
the peaks attributable to the starting material; however, no
new ν(NO) absorptions appear, and no tractable materials can
be isolated from the final orange reaction mixture. Similarly,
the addition of 1 equiv of diphenyl disulfide to a THF solution
of (trimpsi)Nb(CO)2(NO) at -30 °C causes a gradual color
change from red to orange-green. An IR spectrum of the final
reaction solution is devoid of ν(NO) and ν(CO) absorptions, and
no tractable materials can be isolated from the reaction
mixture. Disappointingly, the same reactions with the tanta-
lum congener afford similar results.
mull): ν(NO) 1555 (s) cm-1 1H NMR (CD2Cl2, 500 MHz, 25
.
°C): δ 0.07 (s, SiMe3), 0.56 (dd, J PH ) 7.3 Hz, J HH ) 14.8 Hz,
CH), 0.71-0.85 (m, 4 CH), 0.88 (s, CMe3), 0.99 (m, CH), 1.24
(d, J PH ) 4.9 Hz, PMe), 1.40 (d, J PH ) 5.4 Hz, PMe), 1.42 (d,
J PH ) 7.7 Hz, PMe), 1.55 (d, J PH ) 6.6 Hz, PMe), 1.58 (d,
J PH ) 7.4 Hz, PMe), 1.72 (d, J PH ) 7.6 Hz, PMe), 2.26 (m, Me3-
1
SiCH), 3.13 (m, Me3SiCH). H{31P} NMR (C6D6, 500 MHz, 25
°C): δ -0.06 (d, J HH ) 14.7 Hz, CH), 0.13-0.32 (m, 5 CH),
0.57 (s, SiMe3), 0.73 (s, CMe3), 0.93 (s, PMe), 1.00 (s, PMe),
1.17 (s, PMe), 1.26 (s, PMe), 1.43 (s, PMe), 1.54 (s, PMe), 2.61
(d, J HH ) 10.0 Hz, Me3SiCH), 3.32 (d, J HH ) 10.0 Hz, Me3-
SiCH). 13C{1H} NMR (CD2Cl2, 125 MHz, 25 °C): δ 2.7 (s,
SiMe3), 8.7 (d, J CP ) 8.3 Hz, CH), 8.9 (d, J CP ) 5.0 Hz, CH),
10.0 (br s, CH), 15.7 (dd, J CP ) 16.9, 5.1 Hz, PMe), 16.0-16.4
P r ep a r a tion of (tr im p si)V(NO)(CH2SiMe3)Cl (5). THF
(40 mL) was vacuum-transferred onto an intimate mixture of
(trimpsi)V(NO)Cl2 (1.025 g, 2.2 mmol) and Mg(CH2SiMe3)2‚
x(dioxane) (0.325 g, 2.3 mmol of CH2SiMe3-) at -196 °C. The
reaction mixture was vigorously stirred for 72 h while being
permitted to warm slowly to room temperature. The final
orange suspension was taken to dryness in vacuo, and the
remaining orange powder was dissolved in CH2Cl2 (20 mL).
The orange solution was filtered through a plug of Celite (3 ×
1 cm) supported on a medium-porosity frit, and the plug was
subsequently washed with CH2Cl2 (2 × 10 mL). The combined
orange filtrates were taken to dryness in vacuo, and the
remaining solid was dissolved in THF (20 mL). This solution
was concentrated in vacuo until incipient crystallization, at
which point the mixture was cooled to -30 °C overnight. This
cooling resulted in the deposition of 5 as an orange powder
(0.736 g, 50% yield). Anal. Calcd for C17H44ClNOP3Si2V‚
C8H16O2: C, 45.62; H, 9.19; N, 2.13. Found: C, 45.42; H, 9.33;
(br m, 2 PMe), 17.0 (q, J CP ) 5.0 Hz, CMe3), 18.7 (dd, J CP
)
12.5, 5.0 Hz, PMe), 23.6 (dd, J CP ) 20.0, 6.5 Hz, PMe), 25.0
(dd, J CP ) 14.8, 6.4 Hz, PMe), 24.9 (s, CMe3), 77.9 (br s, Me3-
1
SiCH2). P{1H} NMR (C6D6, 202 MHz, 25 °C): δ -24.9 (br s,
1P), -7.7 (br s, 1P), -5.4 (br s, 1P). MS (LSIMS, thioglycerol
matrix; m/z): 559 [P+].
P r ep a r a tion of (tr im p si)V(NO)(CH2CMe3)Cl (7). THF
(10 mL) was vacuum-transferred onto an intimate mixture of
(trimpsi)V(NO)Cl2 (0.20 g, 0.43 mmol) and Mg(CH2CMe3)2‚
x(dioxane) (0.065 g, 0.41 mmol of CH2CMe3-) at -196 °C. The
reaction mixture was warmed slowly to room temperature
while being vigorously stirred for 2 h. The final orange solution
was taken to dryness in vacuo, and the remaining powder was
dissolved in CH2Cl2 (10 mL). The orange solution was filtered
through a plug of Celite (3 × 1 cm) supported on a medium-
porosity frit, and the plug was subsequently washed with CH2-
Cl2 (10 mL). The solvent was removed from the combined
CH2Cl2 filtrates in vacuo, and the contents of the flask were
dissolved in THF (3 mL). Hexanes (5 mL) were added, and
the resulting solution was cooled to -30 °C overnight to induce
the deposition of 7 as a deep red powder (0.065 g, 30% yield).
Recrystallization of this powder from THF/hexanes provided
the analytically pure material. Anal. Calcd for C18H44ClNOP3-
SiV: C, 43.42; H, 8.91; N, 2.81. Found: C, 43.82; H, 8.63; N,
1
N, 2.17. IR (Nujol mull): ν(NO) 1550 (s) cm-1. H NMR (CD2-
Cl2, 500 MHz, 25 °C): δ 0.03 (s, SiMe3), 0.51 (dd, J HH ) 15.0
Hz, J PH ) 9.0 Hz, CH), 0.72-0.85 (m, 4 CH), 0.87 (s, CMe3),
0.99 (br t, J HH ) 14.8 Hz, J PH ) 12.0 Hz, CH), 1.21 (d, J PH
)
4.8 Hz, PMe), 1.29 (d, J PH ) 5.3 Hz, PMe), 1.41 (d, J PH ) 7.2
Hz, PMe), 1.56 (d, J PH ) 6.4 Hz, PMe), 1.59 (d, J PH ) 7.1 Hz,
PMe), 1.69 (d, J PH ) 7.5 Hz, PMe), 2.56 (m, Me3SiCH), 3.27
(m, Me3SiCH). 1H{31P} NMR (CD2Cl2, 500 MHz, 25 °C): δ 0.03
(s, SiMe3), 0.51 (d, J HH ) 14.9 Hz, CH), 0.72 (d, J HH ) 5.0 Hz,
CH), 0.75 (d, J HH ) 4.5 Hz, CH), 0.81 (s, CH), 0.84 (s, CH),
0.87 (s, CMe3), 0.99 (d, J HH ) 14.8 Hz, CH), 1.21 (s, PMe), 1.29
(s, PMe), 1.41 (s, PMe), 1.56 (s, PMe), 1.59 (s, PMe), 1.69 (s,
PMe), 2.56 (d, J HH ) 10.0 Hz, Me3SiCH), 3.27 (d, J HH ) 10.0
Hz, Me3SiCH). 13C{1H} NMR (CD2Cl2, 125 MHz, 25 °C): δ 1.7
(s, SiMe3), 7.8 (d, J CP ) 6.5 Hz, CH), 8.2 (d, J CP ) 6.5 Hz, CH),
9.1 (br s, CH), 15.0-15.4 (br m, 2 PMe), 15.6 (dd, J CP ) 6.0,
1
2.61. IR (Nujol mull): ν(NO) 1530 (s) cm-1. H NMR (CD2Cl2,
500 MHz, 25 °C): δ 0.46 (m, CHCMe3), 0.54 (dd, J HH ) 15.4,
J HP ) 8.2 Hz, CH), 0.71 (dd, J HH ) 15.0, J HP ) 8.2 Hz, CH),
0.85 (m, CH), 0.88 (s, SiCMe3), 0.92 (m, CH), 1.02 (m, 2CH),
1.19 (d, J PH ) 5.0 Hz, PMe), 1.26 (s, CMe3), 1.33 (d, J PH ) 5.5
Hz, PMe), 1.48 (d, J PH ) 6.4 Hz, PMe), 1.52 (d, J PH ) 7.2 Hz,
PMe), 1.58 (d, J PH ) 7.1 Hz, PMe), 1.66 (d, J PH ) 7.9 Hz, PMe),
3.73 (m, CHCMe3, partially covered by residual THF). 1H{31P}
NMR (CD2Cl2, 500 MHz, 25 °C): δ 0.46 (d, J HH ) 11.6 Hz,
CHCMe3), 0.53 (d, J HH ) 14.8 Hz, CH), 0.85 (d, J HH ) 14.5
Hz, CH), 0.89 (s, SiCMe3), 0.92 (d, CH), 1.19 (s, PMe), 1.24 (s,
CMe3), 1.33 (s, PMe), 1.49 (s, PMe), 1.52 (s, PMe), 1.58 (s, PMe),
1.67 (s, PMe), 3.73 (d, CHCMe3, partially covered by residual
THF). 13C{1H} NMR (CD2Cl2, 125 MHz, 25 °C): δ 8.5 (m,
2CH2P), 11.5 (m, CH2P), 15.0 (dd, J PC ) 18.1, 5.4 Hz, PMe),
15.7 (dd, J PC ) 6.5, 3.8 Hz, PMe), 16.7-17.2 (m, 2PMe and
2.9 Hz, PMe), 16.2 (q, J CP ) 5.5 Hz, CMe3), 16.5 (dd, J CP
)
11.3, 6.3 Hz, PMe), 22.4 (dd, J CP ) 15.4, 6.8 Hz, PMe), 22.6
(dd, J CP ) 18.6, 7.3 Hz, PMe), 24.9 (s, CMe3), 72.9 (br s, Me3-
1
SiCH2). P{1H} NMR (CD2Cl2, 202 MHz, 25 °C): δ -22.7 (br
s, 1P), -4.8 (br s, 2P). MS (LSIMS, thioglycerol matrix; m/z):
498 [P+ - CH3].
P r ep a r a tion of (tr im p si)V(NO)(CH2SiMe3)Br (6). THF
(30 mL) was vacuum-transferred onto an intimate mixture of
(trimpsi)V(NO)Br2 (0.615 g, 1.1 mmol) and Mg(CH2SiMe3)2‚
x(dioxane) (0.168 g, 1.2 mmol of CH2SiMe3-) at -196 °C. The
reaction mixture was warmed slowly to room temperature
while being vigorously stirred for 2 h. The final orange
suspension was taken to dryness in vacuo, and the remaining
orange powder was dissolved in CH2Cl2 (30 mL). The orange
solution was filtered through a plug of Celite (3 × 1 cm)
SiCMe3), 22.3 (dd, J PC ) 13.6, 6.9 Hz, PMe), 24.0 (dd, J PC
)
17.6, 8.5 Hz, PMe), 25.7 (s, SiCMe3), 34.5 (s, CMe3), 39.1 (d,
J PC ) 12.8 Hz, CH2CMe3), 109.7 (br s, CH2CMe3). 31P{1H} NMR
(CD2Cl2, 202 MHz, 25 °C): δ -2.9 (br s, 1P), -5.3 (br s, 1P),
-23.6 (br s, 1P). MS (LSIMS, 3-NBA matrix; m/z): 426
[P+ - CH2CMe3].
supported on
a medium-porosity frit, and the plug was
subsequently washed with CH2Cl2 (2 × 10 mL). The volume
of the combined orange filtrates was reduced in vacuo until a
solid began to precipitate, and the mixture was then cooled to
-30 °C overnight to induce the deposition of 6 as orange
P r ep a r a tion of (tr im p si)V(NO)(Me)Cl (8). THF (20 mL)
was vacuum-transferred onto an intimate mixture of (trimpsi)V-
(NO)Cl2 (0.160 g, 0.35 mmol) and MgMe2‚x(dioxane) (0.028 g,

664 Organometallics, Vol. 23, No. 4, 2004
Hayton et al.
0.36 mmol of Me-) at -196 °C. The reaction mixture was
stirred vigorously for 2 h while being warmed slowly to room
temperature. The final yellow suspension was taken to dryness
in vacuo, and the residue was dissolved in CH2Cl2 (15 mL).
The yellow solution was filtered through a plug of Celite (3 ×
1 cm) supported on a medium-porosity frit, and the plug was
subsequently washed with CH2Cl2 (10 mL). The solvent was
removed from the combined filtrates in vacuo, and the contents
of the flask were dissolved in THF (5 mL). Hexanes (2 mL)
were added, and the resulting solution was cooled to -30 °C
overnight to induce the deposition of 8 as yellow needles (0.039
g, 25% yield). Recrystallization of these needles from THF/
hexanes gave the analytically pure material. Anal. Calcd for
C14H36ClNOP3SiV: C, 38.06; H, 8.21; N, 3.17. Found: C, 37.84;
H, 8.25; N, 3.34. IR (Nujol mull): ν(NO) 1543 (s) cm-1. 1H NMR
Ta ble 1. X-r a y Cr ysta llogr a p h ic Da ta for
Com p lexes 1‚1.5C6H5Me a n d 5‚2C4H8O
1‚1.5C6H5Me
5‚2C4H8O
Crystal Data
empirical formula
cryst habit, color
cryst size (mm)
cryst syst
space group
V (Å3)
C
39.5H59NO5P3SiV C25H60ClNO3P3Si2V
needle, yellow
irregular, red-orange
0.20 × 0.20 × 0.1 0.25 × 0.20 × 0.15
monoclinic
P21/n
triclinic
P1h
4462.4(5)
9.4373(8))
17.004(1)
27.820(3)
90
91.982(3)
90
4
1801.2(4)
9.4054(8)
9.600(2)
20.416(1)
83.455(4)
85.320(4)
80.216(8)
2
a (Å)a
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
(CD2Cl2, 500 MHz, 25 °C): δ 0.55 (dd, J PH ) 7.0 Hz, J HH
)
Z
14.8 Hz, CH), 0.70 (dd, J PH ) 7.9 Hz, J HH ) 14.8 Hz, CH),
0.75-1.00 (m, 4 CH), 0.87 (s, SiCMe3), 1.23 (d, J PH ) 4.9 Hz,
PMe), 1.30 (d, J PH ) 5.3 Hz, PMe), 1.41 (d, J PH ) 7.6 Hz, PMe),
1.54 (d, J PH ) 6.9 Hz, PMe), 1.57 (d, J PH ) 7.6 Hz, PMe), 1.69
(d, J PH ) 7.7 Hz, PMe), 1.94 (d of t, J PH ) 14.0 Hz, J PH ) 7.9
Hz VMe). 1H{31P} NMR (C6D6, 300 MHz, 25 °C): δ 0.31 (d,
J HH ) 14.7 Hz, CH), 0.45-0.74 (m, 5 CH), 0.80 (s, SiCMe3),
1.08 (s, PMe), 1.20 (s, PMe), 1.22 (s, PMe), 1.44 (s, PMe), 1.52
(s, PMe), 1.64 (s, PMe), 2.13 (s, VMe). 13C{1H} NMR (CD2Cl2,
125 MHz, 25 °C): δ 8.4 (dd, J CP ) 14.7, 4.7 Hz, CH2), 8.6 (dd,
J CP ) 14.7, 5.8 Hz, CH2), 10.3 (m, CH2), 15.7 (dd, J CP ) 16.9,
8.5 Hz, PMe), 15.6-15.8 (br m, 2 PMe), 16.3 (dd, J CP ) 16.5,
formula wt
799.85
658.24
1.214
5.74
calcd density (Mg/m3) 1.190
abs coeff (cm-1
F000
radiation (λ (Å))
final R indicesb
)
3.95
1700
708
Mo KR (0.710 69) Mo KR (0.710 69)
Data Refinement
R1 ) 0.165,
wR2 ) 0.204
R1 ) 0.101,
wR2 ) 0.210
2.56
goodness of fit on F2 c 0.95
largest diff peak
0.70 and -0.45
0.68 and -0.71
and hole (e Å-3
)
a
Cell dimensions based on the following: 1‚1.5C6H5Me, 7092
reflections, 6.4° < 2θ < 50.1°; 5‚2C4H8O, 5120 reflections, 6.0° e
6.1 Hz, PMe), 17.1 (q, J CP ) 5.6 Hz, CMe3), 17.2 (dd, J CP
)
b
2θ e 50.5°. Number of observed reflections: 1‚1.5C6H5Me, 2480
12.8, 5.4 Hz, PMe), 21.5 (dd, J CP ) 13.4, 7.5 Hz, PMe), 23.0
(dd, J CP ) 22.5, 7.0 Hz, PMe), 25.7 (s, CMe3), 60.5 (br s, VMe).
31P{1H} NMR (CD3CN, 202 MHz, 25 °C): δ -23.4 (br s, 1P),
-4.4 (br s, 1P), -1.3 (br s, 1P). MS (EI, 300 °C; m/z): 426
[P+ - Me].
(Io > 2σIo); 5‚2C4H8O, 3117 (Io > 3σIo). R1 ) ∑|(|Fo| - |Fc|)|/∑|Fo|;
2
2
4 1/2
wR2
)
[∑(|Fo|
-
|Fc| )2/∑wFo
] . For 1‚1.5C6H5Me w )
[σ2(Fo2) + (0.0485P)2 + 109.80P]-1, where P ) (Max(Fo2, 0) + 2Fc2)/
2
-1
2
3; for 5‚2C4H8O, w ) [σ2Fo
(degrees of freedom)]1/2
] .
c GOF ) [∑(w(Fo - Fc2)2)/
.
X-r a y Cr ysta llogr a p h y. Data collection for each structure
was performed on a Rigaku/ADSC CCD diffractometer using
graphite-monochromated Mo KR radiation at -100 ( 1 °C.
Data for 1‚1.5C6H5Me were collected to a maximum 2θ value
of 50.1° in 0.50° oscillations with 58.0 s exposures. The solid-
state molecular structure was solved by direct methods33 and
expanded using Fourier techniques.34 The material crystallized
with 1.5 molecules of toluene in the asymmetric unit. One
toluene was found to be disordered, but it was modeled
successfully in two orientations using isotropic rigid groups.
The major fragment, C30A-C36A, had a relative population
of 0.59(1), while the minor fragment, C30B-C36B, had a
relative population of 0.41(1). A second toluene residing on an
inversion center was found, but it could not be modeled.
PLATON35 was used to correct the data for any electron
density found in the void space around the inversion center.
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 7314
observed reflections and 407 variable parameters.
Data for 5‚2C4H8O were collected to a maximum 2θ value
of 50.5° in 0.50° oscillations with 50.0 s exposures. The solid-
state molecular structure was solved by direct methods33 and
expanded using Fourier techniques.34 The material crystallized
with two molecules of THF in the asymmetric unit. One THF
was disordered, and both its minor and major conformations
were modeled and 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 4281 observed reflections
and 321 variable parameters.
For both structure solutions and refinements neutral-atom
scattering factors were taken from Cromer and Waber.36
Anomalous dispersion effects were included in Fc;37 the values
for ∆f ′ and ∆f ′′ were those of Creagh and McAuley.38 The
values for the mass attenuation coefficients are those of Creagh
and Hubbell.39 All data sets were corrected for Lorentz and
polarization effects. All calculations were performed using the
CrystalClear software package of Rigaku/MSC40 or SHELXL-
97.41 X-ray crystallographic data for both complexes are
collected in Table 1, and full details of all crystallographic
analyses are provided in the Supporting Information.
Ack n ow led gm en t. We are grateful to the Natural
Sciences 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. P.L. is a
Canada Council Killam Research Fellow.
Su p p or tin g In for m a tion Ava ila ble: Text, tables and a
figure giving details of the isolation and characterization of 9
and complete details of the three X-ray crystallographic studies
as CIF files. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM034227P
(36) Cromer, D. T.; Waber, J . T. International Tables for X-ray
Crystallography; Kynoch Press: Birmingham, U.K., 1974; Vol. IV.
(37) Ibers, J . A.; Hamilton, W. C. Acta Crystallogr. 1964, 17, 781-
782.
(38) Creagh, D. C.; McAuley, W. J . International Tables for X-ray
Crystallography; Kluwer Academic: Boston, 1992; Vol. C, pp 219-
222.
(33) Altomare, A.; Cascarano, M.; Giacovazzo, C.; Guagliardi, A. J .
Appl. Crystallogr. 1993, 26, 343.
(34) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
de Gelder, R.; Israel, R.; Smits, J . M. M. The DIRDIF-94 Program
System; Technical Report of the Crystallography Laboratory; Univer-
sity of Nijmegen, Nijmegen, The Netherlands, 1994.
(39) Creagh, D. C.; Hubbell, J . H. International Tables for X-ray
Crystallography; Kluwer Academic: Boston, 1992; Vol. C, pp 200-
206.
(40) CrystalClear, Version1.3.5b20; Molecular Structure Corp., The
Woodlands, TX, 2002.
(41) Sheldrick, G. M. SHELXL97; University of Go¨ttingen, Go¨ttin-
gen, Germany, 1997.
(35) Spek, A. L. Acta Crystallogr., Sect. A 1990, 46, C34.