Molecular Precursors for the Formation of Transition Metal Pnictides
FULL PAPER
3 5 4
molecular precursor compound is one precondition for the Reaction of [Cl PW(CO) ] with K[Co(CO) ]: A solution of
K[Co(CO)
wise to a solution of [Cl
of THF at Ϫ78 °C. After 30 min, the reaction mixture was allowed
to warm to room temperature and stirred for an additional 14 h.
4
] (1.26 g, 6.00 mmol) in 40 mL of THF was added drop-
PW(CO) ] (0.922 g, 2.00 mmol) in 40 mL
exclusive elimination of CO. Thus, for cluster 2 only CO
elimination occurs under the latter conditions, whereas the
Sb-linked complex 6, which possesses only SbϪMn bonds
3
5
loses Mn(CO) units. Furthermore, the stability and the
n
All volatiles were removed in vacuo and [W(CO)
sublimation under high vacuum at 50 °C. The residue was dissolved
in CH Cl , 5 mL of silica gel was added, and the solution was re-
duced to dryness. Compounds 1 and 2 were separated by column
6
] was removed by
vapour pressure of the eliminated moieties also influence
the decomposition behaviour.
The preliminary results presented in this paper show that
2
2
the use of CO-containing molecular precursors for the chromatography. Compound 1 was eluted with hexane (yellow-
preparation of novel transition metal pnictides seems to be brown fraction) and obtained by recrystallisation from CH Cl
2
2
of substantial potential. Nevertheless, further research is (0.12 g, 12% based on P). Elution with hexane/toluene (10:1)
yielded a purple fraction from which 2 could be isolated after
recrystallisation from CH Cl (0.16 g, 10.2% based on P).
2 2
necessary to obtain more information about the structure
and the properties of these novel compounds.
2
1
1
[W
2
(CO)
9
(µ,η :η :η -P
2
{W(CO)
5
}
2
]
2 2
(5): Solid Na [W (CO)10]
(
0.768 g, 1.11 mmol) was added at room temperature to a solution
Experimental Section
of PBr (0.2 g, 0.74 mmol) in 50 mL of toluene, which immediately
became purple. The solution was stirred for 3 hours and the solvent
3
General Remarks: All manipulations were performed under dry ni-
trogen using standard glove-box and Schlenk techniques. All sol-
vents were freshly distilled from appropriate drying reagents im-
removed in vacuo. Extraction of the remaining solid twice with 10
mL of CH Cl and reduction of the solvent volume to about 10
mL yielded black crystals of 5 after one day at 4 °C (0.15 g, 30%).
2
2
mediately prior to use. IR spectra were obtained with a Bruker Further reduction of the solvent volume gave more product. The
IFS280 spectrometer, and 31P NMR spectra were recorded at room
31
8
P NMR spectrum of the crude reaction mixture in [D ]THF
3
1
temperature with
21.49 MHz) using 85% H
tra were recorded with
a Bruker AMX 300 spectrometer ( P: shows singlets at δ ϭ 103.5 and Ϫ90.8 ppm besides the major
1
3
PO
4
as an external standard; mass spec-
Varian MAT-711 spectrometer.
2 2
singlet at δ ϭ Ϫ122.7 ppm for 5. IR (CH Cl ): ν(CO) ϭ 2051 (vs),
Ϫ1 31
1
a
2035 (s), 1999 (m), 1956 (s, br) cm
Ϫ122.6 (s, J
.
3
P{ H} NMR (CDCl ): δ ϭ
[
7]
[24]
[25]
1
Ϫ1
[{W(CO)
5
}
2
PCl], [Cl
3
PW(CO)
5
]
and K[Co(CO)
4
]
were syn-
P,W 19 19 2 4
ϭ 116 Hz) cm . C O P W (1329.55): calcd. C
thesised according to literature procedures.
17.16; found C 17.23.
Reaction of [{W(CO)
5
}
2
PCl] with K[Co(CO)
4
]: K[Co(CO)
PCl] (1.11 g,
4
] (0.33 g, [{(CO) Mn} Sb] (6): A solution of K[Mn(CO) ] (2.20 g, 9.40 mmol)
5
3
5
1.55 mmol) was added to a solution of [{W(CO)
5
}
2
in 50 mL of THF was added to a solution of SbCl3 (715 mg,
3.13 mmol) in 50 mL of THF at Ϫ78 °C over a period of 1 h. The
reaction mixture was stirred at low temperature for an additional
1 h before the cold bath was removed and the solution warmed to
room temperature. All solvents were evaporated in vacuo and the
remaining residue was extracted with pentane. Filtration through
Celite and storage at Ϫ30 °C yielded 6 as black needles (1.16 g,
1.55 mmol) in 20 mL of THF at Ϫ78 °C. After stirring for 30 min,
the mixture was allowed to reach room temperature within 1 h and
was stirred for an additional 1 h. The reaction mixture was filtered
through Celite, 5 mL of silica gel was added and all solvents were
removed in vacuo. Products 1, 2, 3 and 4 were separated by column
chromatography on silica gel.
5
2%). Note: Care has to be taken that the operations carried out
2
[
Co
2
(CO)
6
(µ,η -P
2
{W(CO)
5
}
2
)] (1): After elution of a purple frac-
at room temperature are performed as quickly as possible to avoid
decomposition. IR (KBr): ν(CO) ϭ 2105 (m), 2071 (s), 1980 (vs,
br) cm . EI-MS: m/z (%) ϭ 706.7 (20) [M ], 678.7 (22) [M
CO], 594.7 (2) [M Ϫ 4 CO], 566.7 (7) [M Ϫ 5 CO], 538.7 (20)
tion with hexane/toluene (10:1) crystals of 1 were obtained by
recrystallisation from CH Cl (0.11 g, 15% based on P). The ana-
lytical data agreed with the literature values.
2
2
Ϫ1
ϩ
ϩ
Ϫ
[7]
ϩ
ϩ
ϩ
ϩ
ϩ
[
Co (CO) (µ -P{W(CO) }] (2): This compound was eluted with
3
9
3
5
[M Ϫ 6 CO], 510.7 (43) [M Ϫ 7 CO], 482.6 (3) [M Ϫ 8 CO],
ϩ
ϩ
ϩ
hexane as a yellowish-brown fraction and obtained as brown plate-
lets after recrystallisation from CH Cl
(0.036 g, 3% based on P). Ϫ 11 CO], 370.6 (17) [M Ϫ12 CO], 342.6 (9) [M Ϫ 13 CO],
314.6 (8) [M Ϫ 14 CO], 286.6 (27) [M Ϫ 15 CO]. C Mn O Sb
454.6 (9) [M Ϫ 9 CO], 426.6 (21) [M Ϫ 10 CO], 398.6 (19) [M
ϩ
ϩ
2
2
3
1
1
ϩ
ϩ
P{ H} NMR (C
agreed with the literature values.
6
D
6
): δ ϭ 41.0 ppm (s, br). The analytical data
(706.72): calcd. C 25.49; found C 25.34.
15
3
15
[8]
[
4
2
6
3
5 2
(CO) WCo (CO) {µ -PW(CO) }
] (3): Elution of a brown fraction Thermogravimetric Analysis: Thermogravimetric analyses were car-
with hexane/toluene (5:1) and recrystallisation from CH
2
Cl
2
ried out with a thermobalance STA 409 from Netzsch either in
yielded 3 as black, metallic crystals (0.07 g, 7% based on P). IR
vacuo or with a dynamic helium gas flow (70 mL/min) at a heating
(
(
KBr): ν(CO) ϭ 2090 (sh), 2064 (s, br), 2046 (sh), 2014 (w), 2007 rate of 5 K/min. The balance was coupled to a quadrupole mass
w), 1991 (sh), 1960 (sh), 1947 (vs, br), 1932 (sh) cmϪ1
.
31
1
P{ H} spectrometer QMG 422 (Balzers) that includes a skimmer system
NMR (C
%) ϭ 821.3 (0.6) [(CO)13PCoW
20Co (1291.57): calcd. C 18.60; found C 18.09.
6
D
6
): δ ϭ Ϫ40.0 (s, w1/2 ϭ 500 Hz) ppm. EI-MS: m/z
for measurements under normal pressure.
ϩ
ϩ
(
C
2 2
] , 457.5 (3.6) [PCoW ] .
X-ray Structure Determination and Details of Refinement: Data
were collected with a STOE STADI4 four-cycle diffractometer for
2 20 2 3
O P W
[
WCo
3
(CO)12{µ
3
-PW(CO)
5
}
3
] (4): A brown fraction eluted with complexes 2, 3 and 4 and for complexes 5 and 6 on an IPDS area-
˚
hexane/toluene (2:1) yielded a small amount of 4 after recrystallis-
ation from CH Cl
detector diffractometer using Mo-K
α
(λ ϭ 0.71069 A) radiation.
2
2
(0.015 g, 2% based on P). IR (KBr): ν(CO) ϭ Machine parameters, crystal data and data collection parameters
2
1
076 (s), 2070 (sh), 2017 (sh), 2003 (sh), 1984 (sh), 1943 (vs, br),
are summarised in Table 1. The structures were solved by direct
Ϫ1 31
1
[26a]
919 (sh), 1891 (sh) cm
.
P{ H} NMR (C
6
D
6
): δ ϭ Ϫ135.3 ppm
(1493.52): calcd. finement on F in SHELXL-93
for non-H atoms. Hydrogen atoms were placed in idealised posi-
methods using SHELXS-86,
with full-matrix least-squares re-
Ϫ1
2
[26b]
(s, JP,W ϭ 87.2, 131.2 Hz) cm . C24Co
3
O
24
P
3
W
3
with anisotropic displacement
C 19.30; found C 19.01.
Eur. J. Inorg. Chem. 2005, 135Ϫ141
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139