Preparation of hydroxylamine and O-methylhydroxylamine complexes of manganese and rhenium

Article abstract of DOI:10.1002/ejic.200600251

Hydroxylamine and O-methylhydroxylamine complexes [M(NH₂OH)(CO) _nP_5-n]BPh₄ and [M(NH₂OCH ₃)(CO)_nP_5-n]BPh₄ [M = Mn, Re; n = 1, 2, 3; P = P(OEt)₃, PPh(OEt)₂, PPh₂OEt] were prepared by allowing hydrides MH(CO)_nP_5-n to react first with triflic acid and then with an excess of hydroxylamine. Bidentate phosphane and phosphite can also be used to prepare both NH₂OH and NH ₂OCH₃ complexes of manganese and rhenium of the [M(NH ₂OR)(CO)₂(P-P){P(OEt)₃}]BPh₄ and [M(NH₂OR)(CO)₃(P-P)]BPh₄ [R = H, CH ₃; P-P = Ph₂POCH₂CH₂OPPh ₂, Ph₂PO(CH₂)₃OPPh₂, Ph₂PN(CH₃)CH₂CH₂N(CH ₃)PPh₂] types with the use of MH(CO)₂(P-P) {P(OEt)₃} and MH(CO)₃(P-P) as precursors. The complexes were characterized spectroscopically and by the X-ray crystal-structure determination of [Re(NH₂OCH₃)(CO)₂{PPh(OEt) ₂}₃]BPh₄ and [Re(NH₂OCH ₃)(CO)₃{Ph₂PO(CH₂) ₃OPPh₂}]BPh₄. Oxidation of the hydroxylamine complexes with Pb(OAc)₄ was studied at -40°C and led to an unstable compound tentatively characterized as a nitroxyl [M]-N(H)=O derivative. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Full text of DOI:10.1002/ejic.200600251

FULL PAPER
DOI: 10.1002/ejic.200600251
Preparation of Hydroxylamine and O-Methylhydroxylamine Complexes of
Manganese and Rhenium
Gabriele Albertin,*[a] Stefano Antoniutti,[a] Jorge Bravo,[b] Jesús Castro,[b]
Soledad García-Fontán,[b] Ma Carmen Marín,[b] and Marco Noè[a]
Keywords: Hydroxylamine / O-Methylhydroxylamine / CO and P ligands / Manganese / Rhenium / Oxidation
Hydroxylamine and O-methylhydroxylamine complexes
[M(NH2OH)(CO)nP5–n]BPh4 and [M(NH2OCH3)(CO)nP5–n]-
BPh4 [M = Mn, Re; n = 1, 2, 3; P = P(OEt)3, PPh(OEt)2,
PPh2OEt] were prepared by allowing hydrides MH(CO)n-
P5–n to react first with triflic acid and then with an excess of
hydroxylamine. Bidentate phosphane and phosphite can also
be used to prepare both NH2OH and NH2OCH3 complexes
of manganese and rhenium of the [M(NH2OR)(CO)2(P–P)-
{P(OEt)3}]BPh4 and [M(NH2OR)(CO)3(P–P)]BPh4 [R = H, CH3;
P–P = Ph2POCH2CH2OPPh2, Ph2PO(CH2)3OPPh2, Ph2PN-
(CH3)CH2CH2N(CH3)PPh2] types with the use of MH(CO)2-
(P–P){P(OEt)3} and MH(CO)3(P–P) as precursors. The com-
plexes were characterized spectroscopically and by the
X-ray crystal-structure determination of [Re(NH2OCH3)(CO)2-
{PPh(OEt)2}3]BPh4 and [Re(NH2OCH3)(CO)3{Ph2PO(CH2)3-
OPPh2}]BPh4. Oxidation of the hydroxylamine complexes
with Pb(OAc)4 was studied at –40 °C and led to an unstable
compound tentatively characterized as
N(H)=O derivative.
a nitroxyl [M]–
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
plexes of Mn, Re, Fe, Ru, and Os stabilized by phosphite
ligands.[6] Recently, we have focused our attention on the
NH2OH molecule and reported the preparation of both
mono- and bis(hydroxylamine) complexes of ruthenium
and osmium of the [MH(NH2OH)P4]+ and [M(NH2OH)2-
P4]2+ types (M = Ru, Os; P = phosphites).[7]
These studies have now been extended to manganese and
rhenium as a central metal to determine whether the syn-
thesis of hydroxylamine complexes can be achieved for
these metals and, if possible, to compare these complexes
with related hydrazine derivatives.[6a,6g] The results of these
studies, which allow the synthesis of the first hydroxylamine
and methylhydroxylamine complexes of manganese and of
new examples for rhenium, are reported here.
Introduction
Despite the very large number of transition-metal com-
plexes that contain monodentate nitrogenous ligands[1] such
as ammonia, amines, imine, nitrile, nitrogen monoxide, hy-
drazine, etc., the coordination chemistry of hydroxylamine,
NH2OH, may be considered somewhat unexplored. A
glance through the literature, in fact, shows that hydroxyl-
amine complexes are very scarce,[2] and only recently have
some examples of complexes of the [MX(NH2OH)(CO)2-
(PPh3)2]CF3SO3 (M
= Ru, Os; X = Cl, Br) and
[Re(NH2OH)(CO)3(PPh3)2]CF3SO3 types been reported.[3]
This feature is rather surprising in view of the fact that
the hydrazine molecule, NH2NH2, which is isoelectronic to
and somewhat similar to NH2OH forms a number of stable
and isolable transition-metal complexes.[4,5] A reason for
the scarce number of hydroxylamine derivatives may be a
result of the presence of the OH group that is bonded to
NH2, which makes the NH2OH a poor ligand either as an
N-bonded, or as an O-bonded group. However, the instabil-
ity of the NH2OH molecule in the free state may also con-
tribute to the fact that the synthesis of hydroxylamine deriv-
atives is somewhat difficult.
Results and Discussion
The synthesis of hydroxylamine complexes of manga-
nese(I) and rhenium(I) was achieved by the reaction of the
MH(CO)nP5–n hydride[6a,8] first with an equimolar amount
of triflic acid (HOTf) and then with an excess of hydroxyl-
amine, as shown in Scheme 1 and Scheme 2.
Protonation of the MH(CO)nP5–n hydride with HOTf
We have interest in the chemistry of transition metal
complexes with nitrogen-containing ligands and have re-
ported the synthesis and the reactivity of hydrazine com-
leads to the evolution of H2 and the formation of the triflate
[6a,8]
complexes M(κ1-OTf)(CO)nP5–n
.
Substitution of the la-
bile κ1-OTf ligand with NH2OH afforded the final hydrox-
ylamine complexes, which were isolated in good yields and
characterized. Crucial for the success of the synthesis is to
carry out the reaction at 0 °C for 5–8 hours and to use a
large excess of free NH2OH. Otherwise, either intractable
[a] Dipartimento di Chimica, Università CaЈ Foscari di Venezia,
Dorsoduro 2137, 30123 Venezia, Italy
[b] Departamento de Química Inorgánica, Universidade de Vigo,
Facultade de Química, Edificio de Ciencias Experimentais,
36310 Vigo, Galicia, Spain
Eur. J. Inorg. Chem. 2006, 3451–3462
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G. Albertin et al.
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Scheme 1. M = Mn (1, 3), Re (2, 4); P = P(OEt)3 (a), PPh(OEt)2 (b); OTf = CF3SO3.
mixtures of products, or very low yields in the complexes [M(NH2OH)(CO)3P2]+could only be prepared through the
are obtained. It should also be noted that only the mono- use of phosphanes that are less π-acidic than PPh(OEt)2,
[M(CO)P4] and the dicarbonyl [M(CO)2P3] fragments with such as PPh2OEt and P–P, which were used in complexes
P(OEt)3 and PPh(OEt)2 ligands allow the synthesis of hy- 5c and 6e. The presence of four strong π-acceptor carbonyl
droxylamine complexes. With tricarbonyl complexes ligands in the [M(CO)4P] fragment makes the metal center
[M(CO)3P2], a different phosphane such as PPh2OEt or so electron-poor that it does not allow for the preparation
Ph2PN(Me)CH2CH2N(Me)PPh2 (P–P) must be used to of hydroxylamine complexes with any phosphane used.
yield hydroxylamine complexes [Mn(NH2OH)(CO)3-
(PPh2OEt)2]BPh4 (5c) and [Re(NH2OH)(CO)3(P–P)]BPh4 somewhat related NH2NH2 ligands toward the [M(CO)n-
(6e) [Scheme 2]. P5–n] fragment reveals that when hydrazine was used the
A comparison between the behavior of NH2OH and the
It seems, therefore, that the electronic properties of the synthesis of mixed-ligand complexes of manganese and rhe-
[M(CO)nP5–n] (M = Mn, Re) fragment are important in de- nium with carbonyl and phosphite compounds was easily
termining the synthesis and the stabilization of the NH2OH achieved with every [M(CO)nP5–n] fragment,[6a,6g] and stable
complexes. In particular, it seems that an electron-poor complexes were even obtained with the tetracarbonyl
metal center is not able to stabilize the coordination of [M(NH2NH2)(CO)4P]+ cation, but hydroxylamine was
NH2OH. With good π-acceptor[9] phosphanes such as found to be a more problematic ligand. Only appropriate
P(OEt)3 and PPh(OEt)2 only mono- and dicarbonyl com- fragments, in fact, allow for the synthesis of the correspond-
pounds [M(NH2OH)(CO)P4]+ and [M(NH2OH)(CO)2P3]+ ing hydroxylamine derivatives, which highlights the fact that
were obtained, while stable tricarbonyl cations NH2OH is a molecule that is hard to coordinate.
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Eur. J. Inorg. Chem. 2006, 3451–3462

Preparation of NH2OH and NH2OCH3 Complexes of Mn and Re
FULL PAPER
Scheme 2.
However, the use of the triflate complex M(κ1-OTf)-
(CO)nP5–n (n = 1, 2, 3) as a precursor allows for the synthe-
sis of the first hydroxylamine complexes of manganese, in
addition to new examples of rhenium derivatives. Only one
example, in fact, of NH2OH complexes of rhenium[3b] is
reported in the literature, while only quantum chemical cal-
culations[10] are reported for hydroxylamine complexes of
manganese.
Scheme 3. M = Re (7, 9, 11), Mn (8, 10); P = P(OEt)3 (a),
PPh(OEt)2 (b).
The results obtained with hydroxylamine prompted us to
extend our study to the use of both N- and O-substituted
NH2OH as a ligand. We began to investigate the behavior
of the N-methyl, NH(CH3)OH, and hydroxylamine towards
the triflate complex M(κ1-OTf)(CO)nP5–n, but in no case
was an N-methylhydroxylamine complex obtained. The ste-
ric hindrance of the methyl group probably prevents the N-
coordination of the NH(CH3)OH molecule.
The O-methylhydroxylamine, on the other hand, quickly
reacts with the triflate complexes M(κ1-OTf)(CO)nP5–n con-
taining monodentate phosphite ligands (P) to give the
NH2OCH3 derivatives 7–11 which were isolated in good
yield and characterized (Scheme 3).
Scheme 4. M = Mn (10), Re (11); P–P = Ph2POCH2CH2OPPh2 (d),
Ph2PN(CH3)CH2CH2N(CH3)PPh2 (e), Ph2PO(CH2)3OPPh2 (f).
complexes were obtained with the NH2OCH3 ligand, and
The reaction also proceeds with triflate precursors Re(κ1- suitable crystals for X-ray crystal-structure determination
OTf)(CO)2(P–P){P(OEt)3} and Re(κ1-OTf)(CO)3(P–P), were also obtained with the O-methylhydroxylamine com-
containing bidentate phosphane ligands, to yield the related plexes 9b and 11f.
NH2OCH3 complexes 9–11, as shown in Scheme 4.
Once crystallized, both the hydroxylamine complexes
The syntheses of the NH2OCH3 complexes 7–11 can be 1–6 and the O-methylhydroxylamine complexes 7–11 are
carried out at room temperature and do not need particular stable as solids and in a solution of polar organic solvents,
attention to give the final complexes in good yields. in which they behave like 1:1 electrolytes.[11] The complexes
Furthermore, in contrast to NH2OH, the tricarbonyl frag- were characterized spectroscopically (Table 1 and Table 2)
ment M(CO)3P2 afforded stable O-methylhydroxylamine and by the X-ray crystal-structure determination of
complexes with all the phosphites used. These results may [Re(NH2OCH3)(CO)2{PPh(OEt)2}3]BPh4 (9b) and [Re-
be attributed to the presence of the methoxy group in (NH2OCH3)(CO)3{Ph2PO(CH2)3OPPh2}]BPh4
(11f),
NH2OCH3, which makes O-methylhydroxylamine a better whose ORTEP drawings are shown in Figure 1 and Fig-
σ-donor than NH2OH. As a result, more thermally stable ure 2.
Eur. J. Inorg. Chem. 2006, 3451–3462
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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G. Albertin et al.
FULL PAPER
Table 1. Selected IR and 300 MHz NMR spectroscopic data for manganese and rhenium complexes.
Compound
IR[a]
Assign-
ment
1H NMR[b,c] Assign-
Spin
system
31P{1H}NMR[b,d]
δ [ppm]
ν [cm–1
]
δ [ppm]
J [Hz]
ment
˜
J [Hz]
[e]
1b
2a
[Mn(NH2OH)(CO){PPh(OEt)2}4]BPh4
3415 m, br
3303 m
3222 m
1884 s
νOH
νNH
6.11 br[e]
5.30 br
OH
NH2
CH2
A4
196.4 s
3.48 m, br
3.19 m, br
1.11 t
νCO
CH3
OH
[e]
[Re(NH2OH)(CO){P(OEt)3}4]BPh4
3434 m, br
3316 w
3230 m
1888 s
νOH
νNH
6.39 t[e]
A4
118.0 s
JH,H = 2.3
6.17 m, br
JP,H = 3.0
4.01 q
NH2
νCO
CH2
CH3
OH
NH2
CH2
CH3
1.27 t
3b
4a
4b
[Mn(NH2OH)(CO)2{PPh(OEt)2}3]BPh4
[Re(NH2OH)(CO)2{P(OEt)3}3]BPh4
[Re(NH2OH)(CO)2{PPh(OEt)2}3]BPh4
3414 m
3289 m
3217 m
2000 s
1909 s
3390 m
3277 m
3221 m
1986 s
1902 s
3417 m
3287 m
3218 m
1998 s
1915 s
νOH
νNH
6.16 br[f]
5.68 t, br
3.78 m
A2B[f]
PA: 189.6
PB: 182.0
JA,B = 84.0
νCO
1.25 m
[e]
νOH
νNH
5.50 t, br[e]
5.05 m, br
4.10–3.30 m
1.31 m
OH
NH2
CH2
CH3
AB2
PA: 142.0
PB: 135.1
JA,B = 36.7
νCO
1.14 t
νOH
νNH
5.79 t, br
5.60 m, br
3.94 m
3.84 m
1.37 m
OH
NH2
CH2
AB2
PA: 139.3
PB: 137.4
JA,B = 36.1
νCO
CH3
1.35 t
4ad
5c
[Re(NH2OH)(CO)2(Ph2POCH2CH2OPPh2){P(OEt)3}]BPh4
3383 m, br
3348 m
3215 m
1988 s
νOH
νNH
4.95 m, br
4.59 m, br
4.50–3.88 m
4.10 m
NH2
OH
CH2
ABC
PA: 124.0
PB: 121.3
PC: 112.6
JA,B = 34.0
JA,C = 248.1
JB,C = 27.2
158.1
νCO
1889 s
1.16 t
CH3
[f]
[Mn(NH2OH)(CO)3(PPh2OEt)2]BPh4
3395 m
3269 m
3223 m
2065 m
1973 s
νOH
νNH
4.65 m, br[g]
4.41 br
3.56 m
NH2
OH
CH2
CH3
A2
νCO
1.15 t, br
1940 s
6e
[Re(NH2OH)(CO)3{Ph2PN(CH3)CH2CH2N(CH3)PPh2}]BPh4
3381 m, br
3243 m
3212 m
2047 s
νOH
νNH
4.87 t, br
3.54 m, br
3.80 m
OH
NH2
CH2
A2
66.1 s
νCO
3.28 m
1979 s
2.50 s
NCH3
1913 s
[g]
7a
8b
[Re(NH2OCH3)(CO){P(OEt)3}4]BPh4
3263 w
3230 m
1881 s
νNH
νCO
νNH
νCO
6.19 qnt[g]
4.00 m
3.49 s
NH2
CH2
OCH3
CH3 phos
NH2
A4
119.0 s
1.26 t
[f]
[Mn(NH2OCH3)(CO)2{PPh(OEt)2}3]BPh4
3269 m
3223 m
1993 s
1907 s
4.88 t[g]
JP,H = 6
3.95 m
2.88 s
A2B
PA: 194.1
PB: 187.9
CH2
OCH3
JA,B = 93.0
1.36 m
1.34 t
CH3 phos
1.30 t
[g]
9b
[Re(NH2OCH3)(CO)2{PPh(OEt)2}3]BPh4
3238 m
2025 s
1909 s
νNH
νCO
4.75 t[g]
JP,H = 6
4.09–3.80 m
2.70 s
NH2
AB2
PA: 139.1
PB: 138.4
JA,B = 34.9
CH2
OCH3
1.37 m
1.32 t
CH3 phos
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 3451–3462

Preparation of NH2OH and NH2OCH3 Complexes of Mn and Re
FULL PAPER
Table 1. Continued
Compound
IR[a]
ν [cm–1
Assign- 1H NMR[b,c]
Assign-
ment
Spin
system
31P{1H}NMR[b,d]
δ [ppm]
]
ment
δ [ppm]
J [Hz]
˜
J [Hz]
9ad
[Re(NH2OCH3)(CO)2(Ph2POCH2CH2OPPh2){P(OEt)3}]BPh4
3245 m
3215 m
1995 s
1891 s
νNH
νCO
4.32 m, br
4.08 m
4.55–4.27 m
2.64 s
NH2
CH2
ABC
PA: 131.0
PB: 113.1
PC: 109.4
JA,B = 33.2
JA,C = 245.2
JB,C = 30.2
188.7 s, br
OCH3
CH3 phos
1.14 t
[e]
10b
10d
11b
[Mn(NH2OCH3)(CO)3{PPh(OEt)2}2]BPh4
[Mn(NH2OCH3)(CO)3(Ph2POCH2CH2OPPh2)]BPh4
[Re(NH2OCH3)(CO)3{PPh(OEt)2}2]BPh4
3261 m
3228 m
2056 m
1975 s
1943 s
3257 m
3225 m
2042 s
1977 s
1945 s
3259 m
3215 m
2072 w
1981 s
1949 s
3271 w
3235 w
2044 s
1971 s
1925 s
3246 m
3217 m
2066 m
1971 s
1950 s
4.83 t[e]
JP,H = 6
4.05 m
2.90 s
1.38 t
4.58 m, br
4.35–4.00 m
3.23 s
NH2
A2
CH2
OCH3
CH3 phos
NH2
CH2
OCH3
νNH
νCO
A2
A2
A2
AB
165.8 s
135.2 s
66.1 s
νNH
νCO
5.48 t
JP,H = 4.5
4.08 m
2.99 s
NH2
CH2
OCH3
CH3 phos
NH2
1.44 s
11e [Re(NH2OCH3)(CO)3{Ph2PN(CH3)CH2CH2N(CH3)PPh2}]BPh4
νNH
νCO
4.32 m
3.81 m
3.26 m
2.54 s, br
CH2
OCH3
NCH3
NH2
+
11f
[Re(NH2OCH3)(CO)3(Ph2POCH2CH2CH2OPPh2}]BPh4
νNH
νCO
4.76 s, br
3.72 m
3.50 m
2.39 s
PA: 110.0
PB: 115.0
JA,B = 32.5
OCH2
OCH3
CH2
1.95 m
[a] In KBr pellets. [b] In CD2Cl2 at 20 °C, unless otherwise noted. [c] Phenyl proton resonances omitted. [d] Positive shift downfield from
85% H3PO4. [e] At –30 °C. [f] At –70 °C. [g] At 0 °C.
Compound 9b does not show any interaction between 95.47(3) is the largest value that corresponds to the chelate
–
the complex cation and the BPh4 anion, but in the case angle of the bidentate ligand. This fact was already ob-
of 11f an interionic interaction, with parameters: distance served in other compounds that bear this ligand[8d] and it
H···Ct1 = 2.66(3) Å, distance N···Ct1 = 3.530(3) Å and an- is probably due to the steric requirement of the ligand.
gle NHCt1 = 167(3)° (where Ct1 is the centroid of one of
For 11f, the eight-membered ring adopts the disposition
the phenyl rings of the anion) indicates an NH-π hydrogen of a chair, in such a way that the phosphorus and the oxy-
bond between the nitrogen of the O-methylhydroxylamine gen atoms are in a planar situation (rms deviation of
–
and a phenyl ring of the BPh4 anion. Compound 11f crys- 0.0229) with the rhenium atom slightly below the plane
tallized with a molecule of CH2Cl2 solvent to give a supra- [0.463(2) Å], and the three carbon atoms form another al-
molecular arrangement of the crystal through a hydrogen- most parallel plane, [dihedral angle of 4.5(4)°] at 1.21(1) Å
bonded network involving the cation [parameters, H···Ct2 (average for the two nearest carbon atoms). This conforma-
= 2.98 Å, C···Ct2 = 3.805(4) Å, angle CHCt2 = 141.2°; tion was previously found for complexes with this ligand.[8d]
H···O4Ј = 2.74 Å, C···O4Ј = 3.649(5) Å, angle CHO4Ј =
152.4°. Symmetry operation 2–x, 2–y, 2–z; Ct2 stands for complexes with phosphonite or phosphinite ligands.[8d,12]
the centroid of the phenyl ring labeled as C31 to C36.] For 9b, the Re–P distances for the mutually trans phos-
The Re–P bond lengths are in the range observed for
In both cationic complexes the rhenium atom is coordi- phonite ligands [2.381(3) Å (average)] are shorter than that
nated in a slightly distorted octahedral fashion. In 9b there of the phosphonite trans to a carbonyl ligand [2.413(3) Å]
are three meridional phosphonite ligands PPh(OEt)2, two because of the stronger π-acceptor character of the CO
cis carbonyl ligands and an N-coordinated O-methylhy- group. The same behavior is observed in compound 11f in
droxylamine. In 11f there are three mer carbonyl ligands, which the Re–P1 distance is shorter [2.3647(8) Å] than Re–
two phosphorus atoms of the bidentated phosphinite ligand P2 [2.4608(8) Å].
PPh2{O(CH2)3O}PPh2, and an N-coordinated O-methylhy-
The Re–C bond lengths in 9b also show the different
droxylamine. The coordination polyhedra in 11f is more ir- trans influence of the ligand: Re–C2 (trans to a P atom) is
regular; the cis angles range from 86.26(9) to 95.47(3)°, and 0.063 Å longer than Re–C3 (trans to an N atom) because
Eur. J. Inorg. Chem. 2006, 3451–3462
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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G. Albertin et al.
FULL PAPER
Table 2. 300 MHz 13C{1H} NMR spectroscopic data for selected manganese and rhenium complexes.
Compound
13C{1H}NMR[a] δ [ppm], J [Hz]
Assignment
CO
[b]
3b
[Mn(NH2OH)(CO)2{PPh(OEt)2}3]BPh4
221.1 m
216.5 m
65.7 d
64.8 d
16.3 s
16.1 s
CH2
CH3
CO
[b]
4b
[Re(NH2OH)(CO)2{PPh(OEt)2}3]BPh4
198.3 m
195.5 m
63.5 m
16.3 m
196.9 m
CH2
CH3
CO
[c]
4ad
[Re(NH2OH)(CO)2(Ph2POCH2CH2OPPh2){P(OEt)3}]BPh4
193.2 m
65.2 s, br
64.8 s, br
63.0 d, JC,P = 8
15.7 d, JC,P = 6
196.3 qnt
66.8 s
CH2 bident.
CH2
CH3
CO
OCH3
CH2
CH3
CO
[b]
7a
8b
[Re(NH2OCH3)(CO){P(OEt)3}4]BPh4
61.7 t
16.3 s
221.8 m
[b]
[Mn(NH2OCH3)(CO)2{PPh(OEt)2}3]BPh4
217.9 m
67.1 s
65.2 d
OCH3
CH2
64.1 d
16.5 s
16.2 s
197.3 m
CH3
CO
[c]
9ad
[Re(NH2OCH3)(CO)2(Ph2POCH2CH2OPPh2){P(OEt)3}]BPh4
193.4 m
66.7 s
OCH3
65.3 s, br
64.1 s, br
62.9 d, JC,P = 8
15.8 d, JC,P = 7
190.1 t, JC,P = 8
189.8 t, JC,P = 10
67.9 s
CH2 bident.
CH2
CH3
CO
[b]
11b
11e
11f
[Re(NH2OCH3)(CO)3{PPh(OEt)2}2]BPh4
OCH3
CH2
CH3
CO
64.7 m
16.3 m
194.2 m
188.3 m
[c]
[Re(NH2OCH3)(CO)3{Ph2PN(CH3)CH2CH2N(CH3)PPh2}]BPh4
66.2 s
OCH3
CH2
NCH3
CO
52.1 t, JC,P = 7
39.5 t, JC,P = 3
191.0 m
[c]
[Re(NH2OCH3)(CO)3(Ph2POCH2CH2CH2OPPh2}]BPh4
189.1 m
65.4 s
OCH3
OCH2
64.7 s, br
63.4 s, br
29.6 s, br
–CH2–
[a] Phenyl resonances omitted. [b] In CD2Cl2 at 20 °C. [c] In CDCl3 at 20 °C.
of the stronger π-acceptor character of the phosphonite li-
gand.
The presence of the NH2OH or NH2OCH3 ligand
in the complexes can be determined by IR and NMR
In both cases, the geometrical parameters of the O-meth- spectroscopy (Table 1). The IR spectra of the hydroxyl-
ylhydroxylamine ligand are in accordance with an sp3 char- amine derivatives show one medium-intensity band at
acter for both the oxygen and the nitrogen atom,[13] and the ν = 3381–3434 cm–1 for the νOH stretch, and two bands
˜
conformation of the ligand is such that all the atoms belong at ν = 3212–3348 cm–1 attributed to the νNH stretch
˜
to the same plane (Re–N1–O1–C1) (rms deviation of 0.0173 of the NH2OH ligand. In the spectra of the related
and 0.0405, respectively). The Re–N bonds are similar to NH2OCH3 complexes only two medium-intensity
those found in previously reported[3b] hydroxylaminerheni- bands at ν = 3215–3271 cm–1 for the νNH stretch were ob-
˜
um(I) complexes.
served.
3456
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 3451–3462

Preparation of NH2OH and NH2OCH3 Complexes of Mn and Re
FULL PAPER
Figure 1. The cation of [Re(NH2OCH3)(CO)2{PPh(OEt)2}3]BPh4 (9b) drawn at 30% probability level.
Figure 2. The cation of [Re(NH2OCH3)(CO)3{Ph2PO(CH2)3OPPh2}]BPh4 (11f) drawn at 30% probability level.
The NMR spectra of the NH2OH complexes 1–5, the NH2OH ligand and one slightly broad multiplet at δ
which contain monodentate phosphite ligands, indicate = 3.54–6.17 ppm for the NH2 protons of NH2OH group.
that they are fluxional. The slightly broad signal that ap- Decoupling experiments and COSY spectra were used to
pears at room temperature in the proton spectra, in fact, confirm these assignments and to determine the value of
resolves into two signals for the ligands at 243 K. At this JH,P for the NH2 protons. Values between JH,P = 2 and
temperature the spectra show, besides the signals for the 3 Hz were determined for the NH2OH complexes 1–5,
phosphite and the BPh4 anion, a triplet at δ = 4.41– which strongly supports the presence of an N-bonded
6.39 ppm (JH,H = 2.3 Hz) attributed to the OH protons of NH2OH ligand.
Eur. J. Inorg. Chem. 2006, 3451–3462
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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3457

G. Albertin et al.
FULL PAPER
The proton spectra of complexes 4ad and 6e, which lence of the two phosphane ligands. The IR spectra show,
contain the bidentate phosphane ligand show, apart from in the νCO region, three bands; one band of medium inten-
no fluxionality, the characteristic signals for the NH2 and sity and two strong bands, which suggests a mer arrange-
the OH protons , in agreement, also in this case, with the ment of the three carbonyl ligands. On the basis of these
presence of the hydroxylamine ligand.
data, a mer-trans geometry III may be proposed for the
The 1H NMR spectra of the NH2OCH3 derivatives show tricarbonyl complexes 5c, 10b, 11b.
a singlet at δ = 2.39–3.49 ppm attributed to the methoxy
The IR spectra of the tricarbonyl complexes 6e, 10d and
group, OCH3, and a multiplet at δ = 4.32–6.19 ppm for the 11e, containing bidentate phosphane ligands, show three
NH2 protons of the O-methylhydroxylamine ligand. De- strong absorptions in the νCO region, which indicates a fac
coupling experiments indicate that the multiplet for the arrangement of the three carbonyl ligands. In the tempera-
NH2 protons is a result of the coupling of the phosphorus ture range between +20 and –80 °C the 31P{1H} NMR
nuclei of the phosphane to the NH2OCH3 ligand with JH,P spectra appear as a sharp singlet, in agreement with the
= 4–6 Hz, which is in agreement with the N-bonded coordi- magnetic equivalence of the two phosphite ligands. On the
nation of the NH2OCH3 ligand.
basis of these data, a fac geometry (IV) can reasonably be
The 31P{1H} NMR spectra of the monocarbonyl com- proposed for these hydroxylamine complexes. Finally, a
plexes [M(NH2OH)(CO)P4]+ and [M(NH2OCH3)(CO)P4]+ mer-cis geometry of type V (Scheme 4), like that found in
(1, 2, 7) appear as a slightly broad signal at room tempera- the solid state, can be proposed for the tricarbonyl complex
ture, which resolves into a sharp singlet at 243 K, in agree- [Re(NH2OCH3)(CO)3{Ph2PO(CH2)3OPPh2}]BPh4
(11f),
ment with the magnetic equivalence of the four phosphite whose IR spectrum shows one medium-intensity band and
ligands. On the basis of these data, a geometry of type I two strong bands in the νCO region. The 31P NMR spec-
(Scheme 1 and Scheme 3), with the carbonyl and the hy- trum has an AB multiplet.
droxylamine ligands in a mutually trans position, can rea-
sonably be proposed.
The mer-cis geometry observed for compound 11f is un-
usual as compared with those of related complexes 10d, 11e
The IR spectra of the dicarbonyl complexes that contain bidentate phosphane ligands and may be at-
[M(NH2OR)(CO)2P3]+ (3, 4, 8, 9) (R = H, CH3) show two tributed to the steric requirement of the Ph2PO-
strong νCO bands which indicate a mutually cis position of (CH2)3OPPh2 ligand, because the π-acceptor properties of
the two carbonyl ligands. These two CO groups, however, the P–P phosphites are very similar in complexes 10d and
are not magnetically equivalent, because they show two 11f.
well-separated multiplets at 221.8 and 193.2 ppm in the 13
C
The fluxional behavior observed in some of our hydrox-
NMR spectra (Table 2). At room temperature, the 31P{1H} ylamine complexes may be due to an intermolecular process
NMR spectra of the dicarbonyl complexes that contain the that involves dissociation of NH2OR or phosphite ligands.
monodentate phosphite ligands (3b, 4a, 4b, 8b, 9b) show a NMR experiments in the presence of free phosphite or hy-
rather broad multiplet which resolves into an AB2 pattern droxylamine, however, seem to exclude such a process.
at temperatures between 0 and –70 °C. This indicates that Therefore, it is plausible to assume that the fluxional pro-
there are two phosphites that are magnetically equivalent cess simply results in the inter-exchange of the position of
but different from the third phosphite. On the basis of these both the P- and the NH2OR ligands at room temperature,
data, a mer-cis geometry of type II (Scheme 1 and and the progressive decrease of this change as the tempera-
Scheme 3) similar to that observed in the solid state for 9b ture is lowered leads to a static A2B or ABC system at
can reasonably be proposed for these dicarbonyl-hydroxyl- –70 °C.
amine derivatives.
Reactivity studies of the hydroxylamine complexes were
In the temperature range between +20 and –80 °C, the undertaken, and the preliminary results indicate that they
31P{1H} NMR spectra of the dicarbonyl complexes 4ad and are relatively robust complexes. Substitution of the NH2OH
9ad appear as an ABC multiplet, which can be easily simu- or NH2OCH3 ligand by carbonyl or phosphane is very slow
lated with the parameters reported in Table 1. These param- at room temperature, while reflux conditions cause the de-
eters indicate that, while two of the JP,P values are compar- composition of the complexes.
able(JP,P = 27–34 Hz) the third is considerably higher than
Oxidation reactions with Pb(OAc)4 were also tested, and
the others (JP,P = 245–248 Hz), which suggests that two of the results show (Scheme 5) that, while the O-methylhy-
the three phosphanes are in a mutually trans position. Tak- droxylamine complexes 7–11 do not react with Pb(OAc)4
ing into account that the IR spectra suggest the presence under any conditions, hydroxylamines 1–6 quickly react
of two CO groups in a mutually cis position, we can then with Pb(OAc)4 at –40 °C to give a pale-yellow solution. Un-
reasonably propose a mer-cis geometry of type II (Scheme 1 fortunately, the solid separated from this solution is not a
1
and Scheme 4) for the complexes containing a bidentate pure species, but its H NMR spectrum shows, in the case
phosphane ligand.
of the oxidation of complex [Re(NH2OH)(CO)2{PPh-
At room temperature, the 31P NMR spectra of the (OEt)2}3]BPh4 (4b), a slightly broad signal at δ = 19.7 ppm.
tricarbonyl cations [M(NH2OH)(CO)3P2]+ (5c) and This resonance may be attributed[2b,3b] to the NH proton
[M(NH2OCH3)(CO)3P2]+ (10b, 11b) appear as a rather of the N(H)=O group of the [Re{N(H)=O}(CO)2-
broad signal which resolves into a sharp singlet as the tem- {PPh(OEt)2}3]+ cation, formed by selective oxidation of the
perature is lowered, which indicates the magnetic equiva- NH2OH ligand, as shown in Scheme 5.
3458
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 3451–3462

Preparation of NH2OH and NH2OCH3 Complexes of Mn and Re
FULL PAPER
Magna 750 FT-IR or Perkin–Elmer Spectrum One spectrophotom-
eter. NMR spectra (1H, 13C, 31P) were obtained with Bruker
AC200, AVANCE 300, and ARX 400 spectrometers at tempera-
tures varying between –90 and +30 °C, unless otherwise noted. 1H-
and 13C spectra are referred to internal tetramethylsilane, while
31P{1H} chemical shifts are reported with respect to 85% H3PO4,
with downfield shifts considered positive. The COSY, HMQC, and
HMBC NMR experiments were performed with their standard
programs. The SwaN-MR and g-NMR software packages[17] were
used to treat the NMR spectroscopic data and for the simulation.
The conductivity of 10–3 mol·dm–3 solutions of the complexes in
CH3NO2 at 25 °C was measured with a Radiometer CDM 83 in-
strument.
Scheme 5. M = Mn, Re.
Unfortunately, the nitroxyl [Re{N(H)=O}(CO)2P3]+ de-
rivatives are unstable even at –40 °C and were separated
only as traces. The IR spectrum of the separated solid did
not show a signal for the nitrosyl [Re]–NO complex, which
would result from the deprotonation of [Re]-N(H)=O . This
observation suggests that the deprotonation does not take
place. Our results, therefore, prove that the M(CO)nP5–n
fragment is able to stabilize the coordination of the hydrox-
ylamine group, but not that of the nitroxyl ligand.
Preparation of the Complexes: The hydride complexes MH(CO)n-
P5–n [M = Mn, Re; P = P(OEt)3, PPh(OEt)2, PPh2OEt; n = 1, 2, 3,
4] were prepared by following the previously reported metho-
d.[6e,8a,8b] The related complexes MH(CO)2(P–P){P(OEt)3} and
MH(CO)3(P–P) [P–P
= Ph2POCH2CH2OPPh2, Ph2PO(CH2)3-
OPPh2, Ph2PN(CH3)CH2CH2N(CH3)PPh2] were also obtained by
a known method.[8c,8d]
[Mn(NH2OH)(CO)nP5–n]BPh4 (1b, 3b, 5c) [P = PPh(OEt)2 (b),
PPh2OEt (c); n = 1 (1); n = 2 (3); n = 3 (5)]: An equimolar amount
of CF3SO3H (0.2 mmol, 18 µL) was added to a solution of the
appropriate hydride MnH(CO)nP5–n (0.2 mmol) in CH2Cl2 (10 mL)
cooled to –196 °C. The reaction mixture was brought to room tem-
perature, stirred for 1 h, and then cooled again to –196 °C. An ex-
cess of hydroxylamine (1 mmol, 0.91 mL of a 1.1  solution in eth-
anol) was added, and the resulting solution was brought to 0 °C
and stirred for 8 h. The solvent was removed under reduced pres-
sure. The oil that was obtained was treated with ethanol (1.5 mL)
containing an excess amount of NaBPh4 (0.4 mmol, 137 mg). A
yellow solid slowly separated out from the resulting solution, which
was allowed to stand at –25 °C overnight to complete the precipi-
tation. The solid was filtered and crystallized at 0 °C from CH2Cl2
and ethanol. Yield: 115 mg for 1b (47%), 131 mg for 3b (62%), and
103 mg for 5c (54%).
Conclusions
In this report we have highlighted that the synthesis of
the unprecedented hydroxylamine and the O-methylhydrox-
ylamine complexes of manganese can be achieved through
the use of mixed-ligand Mn(OTf)(CO)nP5–n complexes with
mono- or bidentate phosphites and carbonyls as precursors.
New NH2OH and NH2OCH3 derivatives of rhenium were
also prepared which allowed for the first structural param-
eters of an O-methylhydroxylamine complex to be obtained.
Oxidation of the hydroxylamine complexes with Pb(OAc)4
at –40 °C was also studied and led to the unstable [M]–
N(H)O nitroxyl derivative.
1b: C65H83BMnNO10P4 (1228.01): calcd. C 63.58, H 6.81, N 1.14;
found C 63.82, H 6.95, N 1.10. ΛM = 55.5 Ω–1 mol–1 cm2.
3b: C56H68BMnNO9P3 (1057.82): calcd. C 63.58, H 6.48, N 1.32;
found C 63.45, H 6.57, N 1.27. ΛM = 56.0 Ω–1 mol–1 cm2.
Experimental Section
General: All synthetic work was carried out under an inert atmo-
sphere by using standard Schlenk techniques or a ffacuum Atmo-
sphere dry-box. Once isolated, the complexes were found to be rela-
tively stable in air, but were stored under an inert atmosphere at
–25 °C. All solvents were dried with appropriate drying agents, de-
gassed on a vacuum line and distilled into vacuum-tight storage
flasks. The phosphite P(OEt)3 (Aldrich) was purified by distillation
under nitrogen, while PPh(OEt)2 and PPh2OEt were prepared by
the method of Rabinowitz and Pellon.[14] The bidentate phos-
5c: C55H53BMnNO6P2 (951.72): calcd. C 69.41, H 5.61, N 1.47;
found C 69.35, H 5.75, N 1.44. ΛM = 51.9 Ω–1 mol–1 cm2.
[Re(NH2OH)(CO)nP5–n]BPh4 (2a, 4a, 4b) [P
= P(OEt)3 (a),
PPh(OEt)3 (b); n = 1 (2); n = 2 (4)]: These complexes were prepared
as per the related manganese complexes 1, 3, 5 with the use of
hydride ReH(CO)nP5–n as a precursor. The reaction mixture was
stirred for 4 h at room temperature. Yield: 175 mg for 2a (71%),
142 mg for 4a (65%), and 147 mg for 4b (62%).
phanes Ph2PO(CH2)nOPPh2 (n
= 2, 3) and Ph2PN(CH3)-
2a: C49H83BNO14P4Re (1231.10): calcd. C 47.81, H 6.80, N 1.14;
found C 48.02, H 6.90, N 1.06. ΛM = 53.8 Ω–1 mol–1 cm2.
CH2CH2N(CH3)PPh2 were prepared by the reported meth-
ods.[8c,8d,15] Re2(CO)10 was purchased from Pressure Chemical Co.
(U.S.A.) while Mn2(CO)10 was purchased from Aldrich, and both
compounds were used as received. Hydroxylamine (NH2OH), N-
methylhydroxylamine [NH(CH3)OH], and O-methylhydroxylamine
(NH2OCH3) were prepared by a slight modification of a reported
method,[16] which involved the treatment of hydroxylamine hydro-
chloride with sodium ethylate in ethanol. The free NH2OH was
isolated as a white solid, while NH(CH3)OH and NH2OCH3 were
prepared in solution just prior to use. Other reagents were pur-
chased from commercial sources in the highest available purity and
used as received. Infrared spectra were recorded with a Nicolet
4a: C44H68BNO12P3Re (1092.95): calcd. C 48.35, H 6.27, N 1.28;
found C 48.44, H 6.25, N 1.19. ΛM = 54.3 Ω–1 mol–1 cm2.
4b: C56H68BNO9P3Re (1189.09): calcd. C 56.57, H 5.76, N 1.18;
found C 56.66, H 5.90, N 1.12. ΛM = 54.7 Ω–1 mol–1 cm2.
[Re(NH2OH)(CO)2(Ph2POCH2CH2OPPh2){P(OEt)3}]BPh4 (4ad):
This complex was prepared as per the related rhenium complexes
2
and 4 with the use of ReH(CO)2(Ph2POCH2CH2OPPh2)-
{P(OEt)3} as a precursor. The reaction mixture was stirred at room
temperature for 6 h. Yield: 131 mg (55%). C58H62BNO8P3Re
Eur. J. Inorg. Chem. 2006, 3451–3462
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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3459

G. Albertin et al.
FULL PAPER
(1191.06): calcd. C 58.49, H 5.25, N 1.18; found C 58.62, H 5.29,
9b: C57H70BNO9P3Re (1203.11): calcd. C 56.90, H 5.86, N 1.16;
found C 57.04, H 5.95, N 1.11. ΛM = 53.5 Ω–1 mol–1 cm2.
N 1.15. ΛM = 50.0 Ω–1 mol–1 cm2.
[Re(NH2OH)(CO)3{Ph2PN(Me)CH2CH2N(Me)PPh2}]BPh4 (6e):
This complex was prepared as per the related rhenium complexes
with the use of hydride ReH(CO)3(Ph2PN(CH3)CH2CH2N(CH3)
PPh2). The reaction was stirred for 7 h at 0 °C; yield 175 mg (81%).
C55H53BN3O4P2Re (1079.00): calcd. C 61.22, H 4.95, N 3.89; found
C 61.05, H 4.88, N 3.68. ΛM = 52.6 Ω–1 mol–1 cm2.
10b: C48H55BMnNO8P2 (901.66): calcd. C 63.94, H 6.15, N 1.55;
found C 64.10, H 6.41, N 1.49. ΛM = 52.1 Ω–1 mol–1 cm2.
11b: C48H55BNO8P2Re (1032.92): calcd. C 55.82, H 5.37, N 1.36;
found C 55.60, H 5.35, N 1.25. ΛM = 55.0 Ω–1 mol–1 cm2.
[Re(NH2OMe)(CO)2(Ph2POCH2CH2OPPh2){P(OEt)3}]BPh4 (9ad):
This compound was prepared as per the related rhenium complexes
7, 9, 11 with the use of hydride ReH(CO)2(Ph2POCH2CH2OPPh2)-
{P(OEt)3}. Yield: 137 mg (57%). C59H64BNO8P3Re (1205.09):
calcd. C 58.80, H 5.35, N 1.16; found C 59.04, H 5.49, N 1.18. ΛM
= 49.6 Ω–1 mol–1 cm2.
[Re(NH2OMe)(CO)nP5–n]BPh4 (7a, 9b, 11b) and [Mn(NH2OMe)-
(CO)nP5–n]BPh4 (8b, 10b) [P = P(OEt)3 (a), PPh(OEt)2 (b); n = 1
(7); n = 2 (8, 9); n = 3 (10, 11)]: An equimolar amount of CF3SO3H
(0.2 mmol, 18 µL) was added to a solution of the appropriate hy-
dride MH(CO)nP5–n (0.2 mmol) in CH2Cl2 (5 mL) cooled to
–196 °C. The reaction mixture was brought to room temperature,
stirred for 1 h, and then cooled again to –196 °C. An excess of
NH2OCH3 (2 mmol, 1.54 mL of a 1.3  solution in ethanol) was
added, and the resulting solution was brought to room temperature
and stirred for about 5 h. The solvent was removed under reduced
pressure. The oil that was obtained was treated with ethanol
(1.5 mL) containing an excess of NaBPh4 (0.4 mmol, 137 mg). A
white or pale-yellow solid slowly separated out from the resulting
solution, which was allowed to stand at –25 °C overnight to com-
plete the precipitation. The solid was filtered and crystallized from
CH2Cl2 and ethanol. Yield: 167 mg for 7a (67%), 133 mg for 8b
(62%), 176 mg for 9b (73%), 123 mg for 10b (68%), and 155 mg
for 11b (75%).
[Mn(NH2OMe)(CO)3(Ph2POCH2CH2OPPh2)]BPh4 (10d) and
[Re(NH2OMe)(CO)3(P–P)]BPh4 (11e, 11f) [P–P = Ph2PN(Me)-
CH2CH2N(Me)PPh2 (e), Ph2PO(CH2)3OPPh2 (f)]: These com-
plexes were prepared as per the related complexes 7–11 with the
use of hydride MH(CO)3(P–P). The reaction was stirred for 5 h.
Yield: 108 mg for 10d (58%), 168 mg for 11e (77%), and 162 mg
for 11f (75%).
10d: C54H49BMnNO6P2 (935.25): calcd. C 69.32, H 5.28, N 1.50;
found C 69.25, H 5.43, N 1.47. ΛM = 55.6 Ω–1 mol–1 cm2.
11e: C56H55BN3O4P2Re (1093.03): calcd. C 61.54, H 5.07, N 3.84;
found C 61.49, H 5.13, N 3.80. ΛM = 52.3 Ω–1 mol–1 cm2.
11f: C55H51BNO6P2Re (1080.97): calcd. C 61.11, H 4.76, N 1.30;
found C 61.25, H 4.87, N 1.24. ΛM = 50.7 Ω–1 mol–1 cm2.
7a: C50H85BNO14P4Re (1245.12): calcd. C 48.23, H 6.88, N 1.12;
found C 48.45, H 6.94, N 1.08. ΛM = 56.9 Ω–1 mol–1 cm2.
Oxidation Reaction: The oxidation of the hydroxylamine and
O-methylhydroxylamine complexes was carried out at low tempera-
ture (–40 °C) by using Pb(OAc)4 as a reagent. In a typical experi-
8b: C57H70BMnNO9P3 (1071.85): calcd. C 63.87, H 6.58, N 1.31;
found C 63.80, H 6.67, N 1.27. ΛM = 55.9 Ω–1 mol–1 cm2.
Table 3. Crystal data and structure refinement for [Re(NH2OCH3)(CO)2{PPh(OEt)2}3]BPh4 (9b) and [Re(NH2OCH3)(CO)3{Ph2PO-
(CH2)3OPPh2}]BPh4 (11f).
Identification code
9b
11f
Empirical formula
Formula weight
Temperature
C57H70BNO9P3Re
1203.06
293(2) K
C56H53BCl2NO6P2Re
1165.84
173(2) K
Wavelength
0.71073 Å
0.71073 Å
Crystal system
Space group
Unit cell dimensions
monoclinic
P21/c
a = 12.707(2) Å
b = 27.279(5) Å
c = 17.486(3) Å
α = 90°
triclinic
P1
¯
a = 10.0187(7) Å
b = 15.7038(11) Å
c = 17.9835(13) Å
α = 94.267(1)°
β = 104.823(1)°
γ = 105.249(1)°
2608.3(3) Å3
β = 106.130(5)°
γ = 90°
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
5822.9(18) Å3
4
2
1.372 Mg/m3
2.222 mm–1
1.484 Mg/m3
2.544 mm–1
2464
1176
Crystal size
Theta range for data collection
Index ranges
0.14×0.11×0.07 mm
1.42 to 28.08°
–15 Յ h Յ 16; –35 Յ k Յ 27; –20 Յ l Յ 22
30713
12872 [R(int) = 0.1441]
3713
0.908
1.000 and 0.753
12872/0/656
0.36×0.23×0.22 mm
1.36 to 28.01°
–12 Յ h Յ 13; –20 Յ k Յ 18; –23 Յ l Յ 18
17230
11960 [R(int) = 0.0424]
10213
0.949
1.000 and 0.739
11960/0/632
0.953
R1 = 0.0301 wR2 = 0.0608
R1 = 0.0400 wR2 = 0.0629
0.989 and –0.890 e·Å–3
Reflections collected
Independent reflections
Reflections observed (Ͼ2σ)
Data completeness
Max. and min. transmission
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [IϾ2σ(I)]
R indices (all data)
Largest diff. peak and hole
0.637
R1 = 0.0555 wR2 = 0.0631
R1 = 0.2593 wR2 = 0.1031
0.837 and –0.600 e·Å–3
3460
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 3451–3462

Preparation of NH2OH and NH2OCH3 Complexes of Mn and Re
ment, a sample of the appropriate complex, [M(NH2OH)(CO)n- Details of crystal data and structural refinement are given in
FULL PAPER
P5–n]BPh4 or [M(NH2OCH3)(CO)nP5–n]BPh4 (0.10 mmol), was
placed in a three-necked, 25-mL, round-bottomed flask fitted with
a solid-addition sidearm containing an equimolar amount of
Pb(OAc)4 (44 mg, 0.10 mmol). The system was evacuated, CH2Cl2
(10 mL) was added, the solution cooled to –40 °C, and the Pb-
(OAc)4 was added portionwise over 10–20 min to the cold solution
with stirring. The reaction mixture was then warmed to 0 °C,
stirred for 10 min, and the solvent was removed under reduced
pressure. The oil obtained was treated at 0 °C with ethanol (2 mL)
containing NaBPh4 (42 mg, 0.12 mmol), but no solid compound
was separated from the resulting solution.
Table 3; selected bond lengths and angles are listed in Table 4 and
Table 5. CCDC-297494 and -297495 contain the supplementary
crystallographic data for this paper. These data can be obtained
free of charge from The Cambridge Crystallographic Data Centre
via www.ccdc.cam.ac.uk/data_request/cif.
Acknowledgments
The financial support from MIUR (Rome, Italy) - PRIN 2004, the
Xunta de Galicia (Project PGIDT04PXIC31401PN), and the Span-
ish Ministry of Education (Project BQU2003–06783) is gratefully
acknowledged. We thank the University of Vigo, CACTI services,
for collecting X-ray data and recording NMR spectra. We also
thank Daniela Baldan, University of Venice, for technical assist-
ance.
X-ray Crystal-Structure Determination of [Re(NH2OCH3)(CO)2-
{PPh(OEt)2}3]BPh4 (9b) and [Re(NH2OCH3)(CO)3{Ph2PO(CH2)3-
OPPh2}]BPh4 (11f): Suitable crystals for X-ray analysis were ob-
tained by slow cooling of a saturated solution of the complexes in
ethanol and CH2Cl2. The data was collected with a SIEMENS
Smart CCD area-detector diffractometer with graphite-monochro-
mated Mo-Kα radiation, at room temperature in the case of 9b and
at –100 °C in the case of 11f. Absorption corrections were carried
out with SADABS with the use of semi-empirical methods from
equivalents.[18] The structures were solved by direct methods in the
case of 9b and by Patterson methods in the case of 11f. Both were
refined by a full-matrix least-squares analysis based on F2.[19] Non-
hydrogen atoms were refined with anisotropic displacement param-
eters. Hydrogen atoms were included in idealized positions and re-
fined with isotropic displacement parameters, except those bonded
to the nitrogen atom in 11f, which were located on the density map
and refined isotropically. Atomic scattering factors and anomalous
dispersion corrections for all atoms were taken from the Inter-
national Tables for X-ray Crystallography (Tables 3, 4 and 5).[20]
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Table 4. Selected bond lengths [Å] and angles [°] for
[Re(NH2OCH3)(CO)2{PPh(OEt)2}3]BPh4 (9b).
Re–C3
Re–N1
Re–P2
O1–C1
C3–Re–C2
C2–Re–N1
C2–Re–P1
C3–Re–P2
N1–Re–P2
C3–Re–P3
N1–Re–P3
P2–Re–P3
O1–N1–Re
1.838(12)
2.223(8)
2.385(3)
1.426(11)
86.1(5)
91.3(4)
87.6(3)
91.0(3)
91.5(2)
96.2(3)
Re–C2
Re–P1
Re–P(3)
O1–N1
C3–Re–N1
C3–Re–P1
N1–Re–P1
C2–Re–P2
P1–Re–P2
C2–Re–P3
P1–Re–P3
C1–O1–N1
1.901(10)
2.378(3)
2.413(3)
1.432(8)
176.3(4)
91.5(3)
85.6(2)
85.4(3)
172.41(10)
177.6(3)
91.53(9)
111.2(8)
86.33(19)
95.31(9)
110.5(5)
Table 5. Selected bond lengths [Å] and angles [°] for
[Re(NH2OCH3)(CO)3{Ph2PO(CH2)3OPPh2}]BPh4 (11f).
Re–C3
Re–C2
Re–P1
N1–O1
C3–Re–C4
C4–Re–C2
C4–Re–N1
C3–Re–P1
C2–Re–P1
C3–Re–P2
C2–Re–P2
P1–Re–P2
C1–O1–N1
1.962(4)
1.998(3)
2.3647(8)
1.440(3)
92.80(13)
175.41(13)
90.57(11)
86.98(9)
87.85(9)
176.74(9)
86.26(9)
95.47(3)
111.3(2)
Re–C4
Re–N1
Re–P2
O1–C1
C3–Re–C2
C3–Re–N1
C2–Re–N1
C4–Re–P1
N1–Re–P1
C4–Re–P2
N1–Re–P2
O1–N1–Re
1.977(3)
2.232(3)
2.4608(8)
1.436(3)
91.70(13)
86.45(12)
90.62(11)
91.47(9)
173.21(9)
89.29(9)
91.03(8)
107.26(16)
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Received: March 21, 2006
Published Online: July 24, 2006
3462
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 3451–3462