Preparations
[{Mo(NS3)(N2H)}n] 5. Anhydrous N2H4 (0.1 g, 3.1 mmol) was
added dropwise to a stirred suspension of complex 1 (0.1 g, 0.3
mmol) in MeCN (30 cm3) and the mixture stirred for 24 h. The
resulting mixture was filtered to give 5 as a dark green-brown
solid which was washed with Et2O and dried in a vacuum. Yield
0.06 g, 60%. Compound 5 is insoluble in common solvents and
diamagnetic in the solid. Found: C, 21.4; H, 4.3; N, 12.8.
C6H13MoN3S3 requires C, 22.6; H, 4.1; N, 13.2%. IR: 3200s(br)
N(CH2CH2SH)3 [NS3H3]. A modification of the literature
method was used. Batches of tris(chloroethyl)amine hydro-
chloride23 (CAUTION: vesicant) were made from 60 g batches
of triethanolamine and converted the same day into tris[2-
(isothioureido)ethyl]amine tetrahydrochloride.24 This work was
carried out in an enclosed Schlenk apparatus while wearing
heavy duty gloves and a face mask. The tetrahydrochloride
was treated in 0.05 or 0.1 mol batches with sodium hydroxide11
giving tris(2-sulfonylethyl)amine NS3H3. The crude product
was not purified by distillation nor by conversion into its hydro-
chloride, but rather it was dissolved in diethyl ether, filtered to
remove a white solid, and the ether removed from the filtrate
in vacuo. The overall yield of NS3H3 from triethanolamine was
30–40%.
[ν(NH)], 1602s(br) cmϪ1 [ν(N᎐N)]. Attempts to deprotonate 5
᎐
to give a dinitrogen complex using LiBut, KOBut or Na in thf
gave dark brown, intractable materials which could not be
characterised and showed no IR absorption characteristic of an
N2 ligand.
[Mo(NS3)(N2HMe)]BF4 6. The compound HBF4ؒEt2O (8.2
mmol, 1.3 cm3 of a solution containing 6.3 mmol cmϪ3 of HBF4
in Et2O) was added dropwise to a stirred suspension of complex
3 (0.2 g, 0.66 mmol) in CH2Cl2 (70 cm3). The solution changed
immediately from burgundy-red to yellow and a brown-
yellow precipitate began to form. It was stirred for 15 min then
allowed to stand overnight, during which time fine brown-
yellow needles of 6 had formed which were filtered off, washed
with CH2Cl2 (5 cm3), then a small amount of Et2O and dried in
a vacuum. The crystals contained one CH2Cl2, probably held by
hydrogen bonding with the BF4Ϫ. Yield 0.17 g, 52%. Found: C,
18.7; H, 3.6; N, 8.8. C8H18BCl2F4MoN3S3 requires C, 19.0; H,
3.6; N, 8.3%. IR: 3260s [ν(NH)], 1161–1080s(br) cmϪ1 [ν(BF4)],
diamagnetic. Attempts to obtain NMR spectra or to recrystal-
lise 6 were frustrated by the ready loss of HBF4 in solvents such
as acetone in which 6 is soluble, regenerating the starting
material 3.
[{MoO(NS3)}2] 1. To a stirred solution/suspension of [MoO2-
(acac)2] (2.0 g, 6.1 mmol) in CH2Cl2 (60 cm3) was added NS3H3
(2.0 g, 15.0 mmol) and the resulting mixture stirred for 16 h to
give an orange-red suspension in a brown solution. The precipi-
tate was filtered off, washed with CH2Cl2 (3 × 4 cm3) and dried
in a vacuum to give complex 1 as an orange-red solid. Yield 1.8
g, 92%. Found: C, 23.4: H, 3.9; N, 5.0; S, 28.9. C6H12MoNOS3
requires C, 23.5; H, 3.9; N, 4.6; S, 31.4%. IR: 937s cmϪ1
[(µMoO)], diamagnetic.
[{Mo(NS3)}2(ꢀ-S)] 2. Diethyl ether (20 cm3) was added to the
brown mother liquor resulting from the preparation of complex
1 above and the resulting solution allowed to stand for 7 d at
room temperature, during which time deep red crystals
deposited on the side of the containing flask. After decanting
the mother liquor, these were carefully removed by hand in a
glove box. Yield 0.05 g, 1.9%. Only one of a number of
attempts to repeat this synthesis was successful, in similar
yield. There were sufficient crystals for IR measurement (no
notable bands), magnetic moment determination (diamagnetic)
and structural characterisation by X-ray crystallography as
described below.
[Mo(NS3)(N2HMe)]Cl 7. Anhydrous HCl (0.5 mmol, 0.5 cm3
of a molar solution in Et2O) was added dropwise to a stirred
suspension of complex 3 (0.1 g, 0.33 mmol) in CH2Cl2 (30 cm3).
The solution changed immediately from burgundy-red to
yellow and a brown-yellow precipitate deposited over 5 min
which was filtered off, washed with CH2Cl2 (5 cm3), then Et2O
(2 × 5 cm3) and dried in a vacuum to give 7 as yellow-brown
microcrystals. The crystals contained CH2Cl2 (0.25 mol). Yield
[Mo(NS3)(N2Me)] 3. The compound H2NNHMe (2.8 g, 51.1
mmol) was added dropwise to a stirred suspension of complex 1
(1.5 g, 4.91 mmol) in CH2Cl2 (75 cm3) and the mixture stirred
for 13 h. The resulting mixture was filtered from a sticky brown
solid, which was not characterised, to give a burgundy-red solu-
tion. This was concentrated to about 20 cm3 in a vacuum then
allowed to stand overnight at 4 ЊC, whereupon dark red crystals
of 3 deposited. Yield 0.85 g, 52%. Recrystallisation from
CH2Cl2–Et2O gave diamagnetic, analytically pure red crystals
which were suitable for X-ray studies. Found: C, 25.4: H, 4.4; N,
12.7. C7H15MoN3S3 requires C, 25.2: H, 4.5; N, 12.6%. IR:
0.06 g, 50%. Found: C, 22.3; H, 4.3; Cl, 13.0; N, 11.0. C7.25H16.5
-
Cl1.5MoN3S3 requires C, 22.3; H, 4.3; Cl, 13.6; N, 10.7%. IR:
3180 cmϪ1 [ν(NH)], diamagnetic. Attempts to obtain NMR
spectra or recrystallise 7 were frustrated by the ready loss of
HCl in solvents such as acetone in which 7 is soluble, regenerat-
ing 3.
[Mo(NS3)(N2HPh)]BF4 8. This complex was prepared in a
similar manner to 6 from 3 (0.02 g, 0.07 mmol) and HBF4ؒEt2O
(0.15 mmol, 0.3 cm3 of a solution containing 0.5 mmol cmϪ3 of
HBF4 in Et2O) in CH2Cl2 (20 cm3). Yield 0.02 g, 52%. It easily
loses HBF4 as for 6 and is diamagnetic. Found: C, 28.8; H, 3.6;
N, 8.6. C12H18BF4MoN3S3 requires C, 29.8; H, 3.8; N, 8.7%. IR:
3180s [ν(NH)], 1161–1080s(br) cmϪ1 [ν(BF4)].
1
3
1610s cmϪ1 [ν(N᎐N)]. H NMR (CD Cl ): δ 3.50 (t, 2 H, J
᎐
2
2
H-H
3
5.7, CH2), 3.43 (t, 2 H, JH-H 5.7 Hz, CH2) and 3.8 (s, 3H,
NCH3).
[Mo(NS3)(N2Ph)] 4. The compound H2NNHPh (0.22 g, 2.0
mmol) was added dropwise to a stirred suspension of complex
1 (0.12 g, 0.36 mmol) in CH2Cl2 (20 cm3) and the mixture
stirred for 24 h. The resulting mixture was filtered from an air-
sensitive, oily black solid which was not characterised, to give
a burgundy-red solution which was concentrated to about 7 cm3
in a vacuum, then Et2O (10 cm3) was added and the resulting
red solution allowed to stand at room temperature overnight,
whereupon dark red crystals of 4 deposited. Yield 0.07 g, 46%.
Recrystallisation from CH2Cl2–Et2O gave analytically pure red
crystals which were suitable for X-ray studies. Found: C, 36.8:
H, 4.4; N, 10.8. C12H17MoN3S3 requires C, 36.5; H, 4.3; N,
[Mo(NS3)(N2Me2)]BF4 9. The salt [Me3O]BF4 (0.7 g, 4.7
mmol) was added dropwise to a stirred solution of complex 3
(0.12 g, 0.36 mmol) in CH2Cl2 (30 cm3) and the mixture stirred
for 24 h. The burgundy-red solution slowly became yellow and
deposited a yellow precipitate which was filtered off, washed
with CH2Cl2 (3 cm3) and dried in a vacuum to give 9 as yellow
microcrystals. Compound 9 reverted to 3 only slowly on stand-
ing in acetone solution, so that NMR data could be obtained.
Yield 0.07 g, 54%. Found: C, 22.1; H, 4.1; N, 9.3. C8H18-
BF4MoN3S3 requires C, 22.1; H, 4.2; N, 9.7%. IR: 1100–1048s
1
3
cmϪ1 [ν(BF4)]. H NMR (acetone-d6): δ 4.03 (t, 2 H, JH-H 5.6,
CH2), 3.82 (t, 2 H, 3JH-H 5.7 Hz, CH2) and 4.15 (s, 6 H, NCH3).
19F NMR (acetone-d6): δ Ϫ151.3.
10.6%. IR: 1601s, 1542s cmϪ1 [ν(N᎐N)], diamagnetic. 1H NMR
᎐
(CD2Cl2): δ 3.54 (t, 2 H, 3JH-H 5.6, CH2), 3.27 (t, 2 H, 3JH-H 5.7,
CH2) and 7.5–7.2 (m, 5 H, NC6H5).
[Mo(NS3)(NO)] 10. Compound 3 (0.17 g, 0.53 mmol) was
J. Chem. Soc., Dalton Trans., 2000, 719–725
723
Davies, Sian C.
