Lithium Cyanide Supported by O- and N-Donors

Article abstract of DOI:10.1002/zaac.201600220

A series of adducts of LiCN, namely [Li(Me₂CO₃)CN], [Li(Et₂CO₃)CN], and [Li(NMP)CN] (NMP = N-methyl-2-pyrrolidone) were prepared by treatment of solvent-free LiCN with the appropriate donor. The starting material for these approaches, donor-free LiCN, was quantitatively prepared from Me₃SiCN and Li[Me] in diethyl ether at 0 °C. Alternatively, [Li(NMP)CN] was synthesized by metathesis reaction of LiCl with NaCN in the presence of stoichiometric amounts of NMP. Although [Li(Me₂CO₃)CN] and [Li(Et₂CO₃)CN] are water-sensitive compounds and decompose at the exposure to air, [Li(NMP)CN] is stable in air, even at elevated temperatures. The thermal stability of [Li(NMP)CN] was proven by differential thermal analysis (DTA). [Li(NMP)CN] shows thermal stability up to temperatures of about 132 °C. To evaluate the cyanation ability the reactions of 1-bromooctane and 3-bromocyclohexene with unsupported LiCN, [Li(NMP)CN], and a mixture of NaCN/LiCl/NMP were investigated. We found that [Li(NMP)CN] as well as LiCl/NaCN/NMP are efficient cyanation reagents comparable to the expensive and air-sensitive, donor-free LiCN. A product of the chloride-cyanide-bromide exchange could be isolated and structurally characterized by X-ray diffraction.

Full text of DOI:10.1002/zaac.201600220

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DOI: 10.1002/zaac.201600220
Lithium Cyanide Supported by O- and N-Donors
Alexandra Budanow,[a] Klaus-Dieter Franz,[a] Hannes Vitze,[a] Lothar Fink,[a]
Edith Alig,[a] Michael Bolte,[a] Matthias Wagner,[a] and Hans-Wolfram Lerner*[a]
Keywords: Lithium cyanide; Lithium; Carbonate esters; Amides; Cyanation reactions; X-ray powder diffraction
Abstract. A series of adducts of LiCN, namely [Li(Me2CO3)CN], mal stability of [Li(NMP)CN] was proven by differential thermal
[Li(Et2CO3)CN], and [Li(NMP)CN] (NMP = N-methyl-2-pyrrolidone) analysis (DTA). [Li(NMP)CN] shows thermal stability up to tempera-
were prepared by treatment of solvent-free LiCN with the appropriate tures of about 132 °C. To evaluate the cyanation ability the reactions
donor. The starting material for these approaches, donor-free LiCN, of 1-bromooctane and 3-bromocyclohexene with unsupported LiCN,
was quantitatively prepared from Me3SiCN and Li[Me] in diethyl ether [Li(NMP)CN], and a mixture of NaCN/LiCl/NMP were investigated.
at 0 °C. Alternatively, [Li(NMP)CN] was synthesized by metathesis
reaction of LiCl with NaCN in the presence of stoichiometric amounts
of NMP. Although [Li(Me2CO3)CN] and [Li(Et2CO3)CN] are
We found that [Li(NMP)CN] as well as LiCl/NaCN/NMP are efficient
cyanation reagents comparable to the expensive and air-sensitive, do-
nor-free LiCN. A product of the chloride-cyanide-bromide exchange
water-sensitive compounds and decompose at the exposure to air, could be isolated and structurally characterized by X-ray diffraction.
[Li(NMP)CN] is stable in air, even at elevated temperatures. The ther-
termediates was given by Ciaccio et al.[9] In addition the tetra-
Introduction
hydrofuran (thf) solvate of LiCN and its acetone adduct are
The chemistry and properties of lithium compounds are of
described as useful intermediates in various organic syntheses
great technological importance as they are already widely
of nitriles. After the breakthrough results of Willner et al. on
the synthesis of higher cyanoborates[10] as weakly coordinating
anions and the use of its lithium salts as potential battery elec-
trolytes, the combination of lithium and cyanide additionally
aroused our interest. In addition organic carbonates are widely
used as electrolyte solvents for Li-ion batteries and therefore
solvate crystal structures serve as useful models for the molec-
ular-level interactions.[11]
In our work we present the stabilization of lithium cyanide
towards hydrolysis and oxidation by forming stable donor ad-
ducts, considering the reactivity and conductivity characteris-
tics of the obtained lithium cyanide material. Up to now ad-
ducts of LiCN are only known with thf or dimethyl formamide
(dmf) as donors.[12] However, the dmf adduct was isolated
along with dimethyl acetamide (dmac) as a non-stoichiometric
compound LiCN·0.6dmf·0.4dmac, whereby Markley et al.
stated: “Attempts to produce single crystals from either pure
dmf or pure dmac solutions were unsuccessful”.[12] Further-
more we found out that while the dmf adduct’s stability is
moderate, the thf adduct of LiCN readily decomposes under
air. This is why there is a need for stable LiCN complexes.
adopted in organic syntheses as a part of inorganic coordina-
tion compounds for pharmaceutical purposes and today ad-
ditionally as a critical element for mobile high density energy
storages.[1] Lithiated carbon compounds or anhydrous lithium
salts in organic solvents are usable for carbon–carbon bond
formation by coupling reactions or as catalysts[2] and espe-
cially as battery electrolytes.[3] Lithium cyanide is a combina-
tion of the smallest reactive metal cation and the cyanide anion
as one of the most versatile carbon nitrogen groups. Further-
more it shows a high solubility in organic donor solvents.
Therefore LiCN is of particular interest as a building block
and can be used for the preparation of organic nitriles as well
as inorganic cyanides and all further subsequent reactions.[1,2,4]
Despite its broad usefulness, its commercial availability is
unreliable[5,6] due to its extreme sensitivity towards humidity,
decomposing to toxic HCN. Hence, LiCN is predominantly
prepared in situ either by reaction of n-butyllithium with HCN
or trimethylsilyl cyanide[7] and by Livinghouse’s method from
acetone cyanohydrin.[8] A recent overview of the organic
chemistry of different LiCN precursors for useful synthetic in-
* Dr. H.-W. Lerner
Fax: +49-69-79829260
Results and Discussion
We first prepared donor-free LiCN by reacting of Me3SiCN
with Li[Me] in diethyl ether at 0 °C (Scheme 1). Thereby
LiCN was obtained in quantitative yield.
E-Mail: lerner@chemie.uni-frankfurt.de
[a] Institut für Anorganische Chemie
Goethe-Universität Frankfurt
Max-von-Laue-Str. 7
60438 Frankfurt, Germany
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/zaac.201600220 or from the au-
thor.
Scheme 1. Synthesis of unsupported LiCN; i) in Et2O at 0 °C.
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As donor-free LiCN is a potent cyanation reagent but is sen-
sitive towards moisture, many attempts were made to stabilize
it with donors like thf or dmf. As the corresponding LiCN
adducts were still poorly stable, our approach was to refine
this idea and to apply methyl and ethyl carbonate instead of
thf and NMP replacing dmf. Heating of mixtures of LiCN
and dimethyl or diethyl carbonate resulted in the adducts
[Li(Me2CO3)CN] and [Li(Et2CO3)CN], respectively (cf. Fig-
ure 1). By cooling the solutions to room temperature, single
crystals of [Li(Me2CO3)CN] and [Li(Et2CO3)CN] were ob-
tained.
The adduct [Li(Me2CO3)CN] crystallizes with one Li cation,
one cyanide anion, and one dimethyl carbonate molecule in
the asymmetric unit (Figure 2). Each Li cation is bonded to the
carbonyl O atom of a dimethyl carbonate molecule, the C atom
of a cyanide anion, and the N atoms of two further cyanide
anions. An N2Li2 four-membered ring is formed via the N
bridging cyanide anions. The cyano C atom, on the other hand,
connects to two four-membered rings. As a result, undulated
layers parallel to (1 0 0) of LiCN are formed. The dimethyl
carbonate molecules occupy the fourth coordination site of the
Li cations (connectivity cf. Figure 1).
[Li(Et2CO3)CN] also features a lithium cyanide adduct (Fig-
ure 3). Despite containing diethyl carbonate instead of di-
Figure 1. Lithium cyanide complexes with Me2CO3, Et2CO3, and
N-methyl-2-pyrrolidone (NMP); repeat unit bounded by wavy lines.
Figure 3. Molecular structure of [Li(Et2CO3)CN]. The probability for
the ellipsoids is 50%. Selected bond lengths /Å and angles /°: Li(1)–
O(1) 1.955(7), Li(1)–N(1)#1 2.037(7), Li(1)–N(1)#2 2.096(7), Li(1)–
Figure 2. Molecular structure of [Li(Me2CO3)CN]. The probability for C(1) 2.148(7), Li(1)–Li(1)#3 2.719(12), N(1)–C(1) 1.137(5), N(1)–
the ellipsoids is 50%. Selected bond lengths /Å and angles /°: Li(1)– Li(1)#4 2.037(7), N(1)–Li(1)#5 2.096(7), O(1)–C(2) 1.187(5), O(2)–
O(1) 1.976(6), Li(1)–N(1)#1 2.048(6), Li(1)–N(1) 2.099(6), Li(1)– C(2) 1.332(5), O(2)–C(3) 1.453(5), O(3)–C(2) 1.325(5), O(3)–C(5)
C(1)#2 2.114(6), Li(1)–Li(1)#1 2.734(10), N(1)–C(1) 1.138(4), N(1)–
Li(1)#1 2.048(6), C(1)–Li(1)#3 2.114(6), O(1)–C(2) 1.204(4), O(2)–
1.470(5), C(3)–C(4) 1.481(7), C(5)–C(6) 1.480(6), O(1)–Li(1)–N(1)#1
112.2(3), O(1)–Li(1)–N(1)#2 106.7(3), N(1)#1–Li(1)–N(1)#2 97.7(3),
C(2) 1.319(4), O(2)–C(3) 1.453(5), O(3)–C(2) 1.323(4), O(3)–C(4) O(1)–Li(1)–C(1) 103.3(3), N(1)#1–Li(1)–C(1) 115.5(3), N(1)#2–
1.453(4), O(1)–Li(1)–N(1)#1 111.0(3), O(1)–Li(1)–N(1) 99.3(3), N(1) Li(1)–C(1) 121.3(3), O(1)–Li(1)–Li(1)#3 120.3(4), C(1)–Li(1)–Li(1)
#1–Li(1)–N(1) 97.5(2), O(1)–Li(1)–C(1)#2 112.3(3), N(1)#1–Li(1)– #3 136.3(4), C(1)–N(1)–Li(1)#4 155.0(4), C(1)–N(1)–Li(1)#5
C(1)#2 116.0(3), N(1)–Li(1)–C(1)#2 118.8(3), O(1)–Li(1)–Li(1)#1 122.1(3), Li(1)#4–N(1)–Li(1)#5 82.3(3), N(1)–C(1)–Li(1) 174.3(4),
113.1(3), C(1)–N(1)–Li(1)#1 145.7(3), C(1)–N(1)–Li(1) 130.7(3), C(2)–O(1)–Li(1) 147.6(3), C(2)–O(2)–C(3) 115.3(3), C(2)–O(3)–C(5)
N(1)–C(1)–Li(1)#3 173.8(3), C(2)–O(1)–Li(1) 133.2(3), C(2)–O(2)– 116.4(3), O(1)–C(2)–O(3) 127.0(4), O(1)–C(2)–O(2) 125.9(4), O(3)–
C(3) 115.4(3), C(2)–O(3)–C(4) 114.9(3), O(1)–C(2)–O(2) 126.0(3), C(2)–O(2) 107.1(4), O(2)–C(3)–C(4) 106.8(4), O(3)–C(5)–C(6)
O(1)–C(2)–O(3) 125.8(3), O(2)–C(2)–O(3) 108.2(3). Symmetry trans-
formations used to generate equivalent atoms: #1 –x+1,–y+1,–z+1 #2
x, –y+1/2, z+1/2 #3 x, –y+1/2, z–1/2.
105.9(4). Symmetry transformations used to generate equivalent
atoms: #1 –x+3/2, y–1/2, z #2 x–1/2, –y+3/2, –z #3 –x+1, –y+1, –z
#4 –x+3/2, y+1/2, z #5 x+1/2, –y+3/2, –z.
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methyl carbonate this structure displays the same motif as the
previous one. Two Li cations and the N atoms of two cyanide
anions are connected to four-membered rings, which are fur-
ther connected to undulated layers parallel to (0 0 1) by the C
atoms of the cyanide ions (cf. Figure 1). The diethyl carbonate
molecules occupy the fourth coordination site of the Li cations.
The crystal packing of [Li(Et2CO3)CN] and [Li(Me2CO3)CN]
is very similar.
In the crystal structures of [Li(Me2CO3)CN] and
[Li(Et2CO3)CN], the Li cations and the N atoms of the cyanide
anions form four-membered rings. Two symmetry equivalent
rings are connected by the C atoms of the cyanide anions. As
a result of that, a twelve-membered ring consisting of four-
membered rings is formed. The Li cations are further bonded
to the carbonyl O atom of the terminating ligands dimethyl
carbonate and diethyl carbonate, respectively (Figure 4 and
Figure 5).
Figure 5. Linkage of [Li(Et2CO3)CN]2-units in the crystal structure of
[Li(Et2CO3)CN]; color code: black C, magenta Li, blue N, and red O.
could also be described as sheets of NMP rings, which are
connected by Li2O2 rings (see Figure 6 and Figure 7).
The local structure of [Li(NMP)CN], as well as the crystal
packing, differ from those of [Li(Me2CO3)CN] and
[Li(Et2CO3)CN]. The crystal structure of [Li(NMP)CN] re-
veals four-membered Li2O2 rings. The cyanide anions are not
part of these rings, but connect two rings, which results in
sixteen-membered rings (Figure 7).
Even as solids [Li(Me2CO3)CN] and [Li(Et2CO3)CN] are
water-sensitive and turn brown at the exposure to air. In con-
trast, [Li(NMP)CN] is air-stable, even at elevated tempera-
tures. The diagrams of differential thermal analysis (DTA/
TGA) of [Li(NMP)CN] in a stream of nitrogen (Figure S1,
Supporting Information), as well as in air (Figure S3, Support-
Figure 4. Linkage of [Li(Me2CO3)CN]2 units in the crystal structure
of [Li(Me2CO3)CN]; color code: black C, magenta Li, blue N, and red
O.
When a slurry of LiCN in hexane and NMP was stirred ing Information), are comparable. Both DTA diagrams show
overnight at room temperature, the complex [Li(NMP)CN] an endothermic effect at about 132 °C, which could be a melt-
was formed and could be characterized by X-ray powder dif- ing or a phase transition (no change in mass) followed by a
fraction.
second endothermic signal with weight losses of 65% (86.4%
[Li(NMP)CN] is another lithium cyanide complex, again of one equivalent NMP) in a nitrogen atmosphere and of 66%
with a different donor, NMP in the present case. The Li atoms (87.8% of one equivalent NMP) in compressed air at tempera-
are tetrahedrally coordinated by two oxygen atoms of NMP tures of about 172 °C (cf. Figures S1 and S3). This temperature
rings and two CN groups. Thus, a Li2O2 four-membered ring is far higher than the allowable operating temperature in Li
is formed and the rings are linked by cyanide anions to stacks battery cells. Until 300 °C the decomposition of [Li(NMP)CN]
parallel to (001). Herein, the NMP rings show a different ori- is not finished in both experiments. As a consequence, the ex-
entation of the methyl groups from step to step (zigzag). This perimental weight losses are less than the calculated values.
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duct in an easier and cheaper way. Our approach was the me-
tathesis reaction of LiCl with NaCN in the presence of a stoi-
chiometric amount of NMP in hexane. This reaction in hexane
yielded quantitatively a 1:1 mixture of [Li(NMP)CN] and
NaCl (Scheme 2) as was verified by X-ray powder diffraction.
Scheme 2. Synthesis of [Li(NMP)CN] by metathesis of LiCl with
NaCN and an equimolar amount of NMP.
Up to now, in the literature not much was reported about
lithium cyanide as a cyanation reagent.[13] Harusawa et al. de-
scribed the reaction of lithium cyanide with various bromo-
and iodoalkenes including 1-bromo- and 1-iodooctane, which
resulted in the corresponding cyano derivatives up to 90%
yield after refluxing in thf for 1 h. In contrast, potassium and
sodium cyanides did not generate even traces of 1-cyanooc-
tane, even after 15 h refluxing. These results indicated the su-
periority of the application of LiCN, however under non-aque-
ous conditions. The use of LiCN as a cyanation reagent even
allowed the conversion of benzyl and allyl halides into the
corresponding cyanides.[13] However, these reactions had to be
water-free, which lead to the problem of more complex and
therefore more expensive reaction conditions.
Figure 6. Molecular structure of [Li(NMP)CN] in the crystal. Selected
bond lengths /Å and angles /°: N(11)–C(12) 1.391(5), N(11)–C(15)
1.409(6), N(11)–C(16) 1.473(5), C(12)–O(1) 1.250(6), C(12)–C(13)
1.543(6), C(15)–C(14) 1.588(6), O(1)–Li(1) 2.10(1), O(1)–Li(2)
2.151(1), C(1)–N(1) 1.099(7), N(1)–Li(1) 1.99(1), Li(2)–C(2)
2.024(2), Li(2)–N(2) 1.87(2), Li(2)–O(2) 2.23(1), C(2)–N(2) 1.151(7),
N(21)–C(22) 1.364(6), N(21)–C(25) 1.466(5), N(21)–C(26) 1.431(5),
C(22)–O(2) 1.273(6), C(22)–C(23) 1.495(6), C(25)–C(24) 1.486(6),
O(2)–Li(1) 2.19(1), O(2)–Li(2) 2.23(1), O(1)–Li(1)–O(2) 81.0(5),
O(1)–Li(2)–O(2) 78.8(5), Li(1)–O(2)–Li(2) 97.6(5), Li(1)–O(1)–Li(2)
102.6(5).
To evaluate the cyanation ability of the cyanide sources of
our approaches the following reactions were performed
(Scheme 3).
Scheme 3. Cyanation ability of LiCN, [Li(NMP)CN], and NaCN/LiCl/
NMP. (i) +LiCN, –LiBr; (ii) +[Li(NMP)CN], –LiBr, –NMP; (iii) +
NaCN/LiCl/NMP, –LiBr, –NaCl, –NMP.
For this, mixtures of unsupported lithium cyanides or its
donor adducts and 1-bromooctane or 3-bromocyclohexene in
thf were heated for 1 h to 70 °C (mixture proportions see
Table 1). The yields were determined by NMR spectroscopy
by the ratio of the normalized integrals of the signals of the
starting material to those of the products.
Figure 7. Packing diagram of [Li(NMP)CN]; color code: black C, ma-
genta Li, blue N, and red O.
The resulting powders after heating were verified by XRPD.
It is interesting to note that from the solution of the reaction
After heating in air, Li2CO3 and LiOCN were present. Heating between 3-bromocyclohexene and NaCN/LiCl/NMP we could
in a nitrogen atmosphere reveals a product, in which only very isolate cocrystals, which consisted of two LiBr, two LiCl, four
weak peaks of LiCN are detectable (cf. Figures S2 and S4, NMP and four H2O molecules. This finding may be envisaged
Supporting Information).
as a further proof of the conversion of 3-bromocyclohexene
As the stability of [Li(NMP)CN] is very promising for many with NaCN/LiCl/NMP into 3-cyanocyclohexene and LiBr. One
applications, we were looking for a way to synthesize this ad- of these crystals was analyzed by single crystal diffraction.
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Table 1. Cyanationa) of 1-bromooctane and 3-bromocyclohexene.
Cyanation reagent [mg] / [mmol] 1-Bromooctane [mL] / [mmol] 3-Bromocyclohexene [mL] / [mmol] Yield /%
LiCN
26 / 0.79
23 / 0.17
81 / 0.43
30 / 0.91
62 / 0.47
43 / 0.23
0.05 / 0.29
0.01 / 0.06
0.08 / 0.46
–
–
–
–
–
–
51
53
45
50
20
50
[Li(NMP)CN]
NaCN/LiCl/NMP
LiCN
[Li(NMP)CN]
NaCN/LiCl/NMP
0.05 / 0.29
0.05 / 0.29
0.02 / 0.10
a) Temperature 70 °C; time 1 h.
This cocrystal is composed of Li cations, which are con-
nected to Li2O2 four-membered rings by the oxygen atoms of
N-methyl-pyrrolidone molecules (Figure 8). The Li(1)/Li(1a)
cations are also included in another four-membered ring
formed by the oxygen atom of another N-methyl-pyrrolidone
molecule, a second Li cation [Li(2)/Li(2a)], and a halogen
anion. The halogen position is shared by a bromine and chlo-
rine anion with a refined site occupation factor of 0.723(2) for
Cl and 0.277(2) for Br. The coordination sphere of the terminal
Li(2)/Li(2a) cations is completed by two water molecules. The
charge is balanced by bromide anions, which are bonded with
hydrogen bonds to the water molecules. As a result, this struc-
ture is not polymeric, but composed of centrosymmetric
[Li4Cl2(C5H9NO)4(H2O)4] cations and bromide anions.
Conclusions
In this study, we investigated the influence of N- and
O-donors on the accessibility, stability, and reactivity of
lithium cyanide complexes. The crystal structures of
[Li(Me2CO3)CN], [Li(Et2CO3)CN], and [Li(NMP)CN] reveal
four-membered Li2N2 and Li2O2 rings. In contrast to the re-
lated carbonates, [Li(NMP)CN] is air-stable, even at elevated
temperatures. Additionally, the reactions of 1-bromooctane and
3-bromocyclohexene with unsupported LiCN, [Li(NMP)CN],
and a mixture of NaCN/LiCl/NMP were investigated to evalu-
ate the cyanation ability. It turned out, that [Li(NMP)CN] as
well as LiCl/NaCN/NMP are efficient cyanation reagents com-
pared to the expensive and air-sensitive donor-free LiCN. In
the end, the cyanation reaction with stable mixtures of NaCN/
LiCl/NMP gets more convenient and therefore opens further
strategies in the organic synthesis.
Experimental Section
General Considerations: All reactions and manipulations were car-
ried out in a dry, oxygen-free nitrogen or argon atmosphere by using
standard Schlenk ware or in an argon-filled M. Braun glovebox. The
solvents thf, [D8]thf, Et2O, pentane, benzene and [D6]benzene were
stirred over sodium/benzophenone and distilled prior to use. CH2Cl2
and CD2Cl2 were dried with CaH2 and freshly distilled prior to use.
The NMR spectra were recorded with a Bruker DPX 250, a Bruker
Avance 300, Avance 400, and Avance 500 spectrometer. Elemental
analyses were performed at the microanalytical laboratories of the Uni-
versität Frankfurt.
Synthesis of LiCN: To a solution of methyllithium (30.0 mmol,
37.5 mL, 0.8 m) in diethyl ether trimethylsilyl cyanide (32.0 mmol,
3.175 g, 4.0 mL) was added at 0 °C over a period of 5 min. Instantly,
a colorless solid precipitates. After the complete addition, the mixture
was warmed to room temperature and stirred for 2 h. The solvent was
decanted and the remaining solid washed with ethyl ether (2ϫ3 mL).
All volatile components were removed under reduced pressure and the
Figure 8.
Molecular
structure
of
the
cocrystal
2LiBr·2LiCl·4NMP·4H2O. The probability for the ellipsoids is 50%.
Selected bond lengths /Å and angles /°: Cl(1)–Li(1) 2.396(4), Cl(1)–
Li(2) 2.401(4), Li(1)–O(1) 1.928(4), Li(1)–O(11) 1.932(4), Li(1)–O(1)
#1 1.945(4), Li(1)–Li(1)#1 2.736(7), Li(1)–Li(2) 2.860(5), Li(2)–
O(2 W) 1.911(4), Li(2)–O(1 W) 1.928(4), Li(2)–O(11) 2.013(4), remaining LiCN was dried. LiCN was obtained in quantitative yield
Li(1)–Cl(1)–Li(2) 73.21(12), O(1)–Li(1)–O(11) 122.9(2), O(1)–Li(1)–
O(1)#1 90.12(16), O(11)–Li(1)–O(1)#1 118.5(2), O(1)–Li(1)–Cl(1)
113.67(17), O(11)–Li(1)–Cl(1) 97.89(15), O(1)#1–Li(1)–Cl(1)
115.26(17), Li(1)–Cl(1)–Li(2) 73.21(12), O(1)–Li(1)–O(11) 122.9(2),
O(1)–Li(1)–O(1)#1 90.12(16), O(11)–Li(1)–O(1)#1 118.5(2), O(1)–
Li(1)–Cl(1) 113.67(17), O(11)–Li(1)–Cl(1) 97.89(15), O(1)#1–Li(1)–
Cl(1) 115.26(17), O(2 W)–Li(2)–O(1 W) 98.04(18), O(2 W)–Li(2)–
O(11) 117.2(2), O(1 W)–Li(2)–O(11) 113.68(19), O(2 W)–Li(2)–Cl(1)
114.63(18), O(1 W)–Li(2)–Cl(1) 119.23(18), O(11)–Li(2)–Cl(1)
95.50(14). Symmetry transformations used to generate equivalent
atoms: #1 –x+1, –y+1, –z+1.
and stored at room temp. in argon-filled glove box.
Synthesis of [Li(Me2CO3)CN]: LiCN (0.052 g, 0.15 mmol) was sus-
pended in dimethyl carbonate (10.0 mL) and the mixture was heated
to boiling. The hot, clear supernatant was filtered and slowly cooled
down for crystallization. After cooling to room temperature colorless,
very hygroscopic needles (yield: 89%) of [Li(Me2CO3)CN] were ob-
tained, which were suitable for X-ray single crystal diffraction.
C4H6LiNO3 (123.04): calcd. C 39.05; H 4.92; N 11.38%; found: C
38.75; H 4.62; N 11.04%.
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Synthesis of [Li(Et2CO3)CN]: LiCN (0.050 g, 0.15 mmol) was sus- X-ray Powder Diffraction: The samples consisting of microcrystal-
pended in diethyl carbonate (10.0 mL) and the mixture was heated to line powder were sealed in borosilicate glass capillaries of 0.7 mm
boiling. The hot, clear supernatant was filtered and slowly cooled for diameter. The measurements were carried out in Debye-Scherrer setup
crystallization. After cooling to room temperature colorless needles of with a STOE STADI P diffractometer, equipped with a curved Ge(111)
[Li(Et2CO3)CN] were obtained (yield: 87%), which were suitable for monochromator to produce pure Cu-Kα1 (λ = 1.5406 Å) radiation. The
X-ray single crystal diffraction. C6H10LiNO3 (151.09): calcd. C 47.70; spun samples were measured at 2θ angles from 2° to 100° in 0.01°
H 6.67; N 9.27%; found: C 47.37; H 6.42; N 8.97%.
steps. With a measurement time of about 20 h, the data was recorded
by a linear position sensitive detector (lin PSD, STOE, Kr/CH4) and
evaluated with the software package WINXPow.[17]
Synthesis of [Li(NMP)CN]: To a slurry of LiCN (0.020 g, 0.61 mmol)
in hexane (4 mL) water-free 2-N-methylpyrolidone (0.1 mL,
1.04 mmol) was added and stirred overnight at room temperature. The
solvent was slowly evaporated over a period of 3 d and [Li(NMP)CN]
was obtained quantitatively as a white powder suitable for X-ray pow-
der diffraction. C6H9LiN2O (132.09): calcd. C 54.56; H 6.87; N
21.21%; found: C 54.08; H 6.62; N 20.78%.
Low-temperature measurements were performed at 100 K using a
CRYOSTREAM 700Plus from OXFORD CRYOSYSTEMS.
Structure Solution: Indexing with DICVOL[18] revealed an ortho-
rhombic unit cell with the parameters a = 18.99 Å, b = 18.00 Å, c =
8.68 Å, V = 2968.7 Å3 and Z = 16, estimated with Hofmann’s volume
increments.[19] With a molecular model of the compound, containing
independent NMP rings, Li atoms and CN groups, the structure was
solved in space group Pbca (no. 61) using simulated annealing in the
program DASH.[20] The low-temperature data were treated similarly.
Reaction of LiCI with NaCN in the Presence of NMP: To a mixture
of water-free LiCl (0.501 g, 11.80 mmol) and NaCN (0.582 g,
11.80 mmol), hexane (2 mL) and water-free NMP (4.5 mL, 4.635 g,
46.76 mmol) was added and the heterogeneous slurry was stirred for
one week at room temperature. After removing of the solvent a color-
less, crystalline solid was obtained which was identified as a 1:1 mix- Refinement: Rietveld refinements of the crystal structures were car-
ture of NaCl and [Li(NMP)CN] by X-ray powder diffraction.
ried out with the program TOPAS.[16] The NMP rings were restrained
on both, bond lengths and angles, the CN groups were restrained on
bond lengths only. Isotropic atomic displacement parameters (ADPs)
were refined separately for Li and all non-hydrogen atoms, while the
ADP for hydrogen was constrained to be 1.2 times the non-hydrogen
ADP. The refinement of [Li(NMP)CN] converged with a goodness of
fit (gof) of 1.21, whereas the Rwp was found to be 3.56% (Table 2).
The orientation of the CN groups was determined by changing the
positions of C and N atoms of these groups, and refining the model
separately for each set. As only a distance restraint (C-N) was set per
CN group, the R values should indicate for the correct position of C
and N inside each group. Checking the bond lengths to the respective
Li atoms confirmed the distribution of C and N atoms.
Reaction of 1-Bromooctane with LiCN, [Li(NMP)CN], and the
Mixture of LiCl/NaCN/NMP: In sealed NMR tubes mixtures of the
LiCN-containing salt and 1-bromooctane (mixture proportions see
Table 1) in 0.7 mL [D8]thf were heated for 1 h at 70 °C. The yields
were determined with 13C NMR spectra by comparing the normalized
integrals of the signals of the starting material and the product.
1-Bromooctane: 13C NMR (75 MHz, [D8]thf): δ = 14.2, 22.6, 27.9,
28.5, 29.0, 31.7, 32.6, 35.2 ppm.
1-Cyanooctane: 13C NMR (75 MHz, [D8]thf): δ = 14.1, 17.2, 22.8,
25.6, 28.8, 29.1, 32.0, 120.0 ppm.
Reaction of 3-Bromocyclohexene with LiCN, [Li(NMP)CN], and
the Mixture of LiCl/NaCN/NMP: In sealed NMR tubes mixtures of
the LiCN-containing complexes and 3-bromocyclohexene (mixture
proportions see Table 1) in 0.7 mL [D8]thf were heated for 1 h at
70 °C. The yields were determined with 13C NMR spectra by compar-
ing the normalized integrals of the signals of the starting material and
the product.
Table 2. Crystallographic data of [Li(NMP)CN].
[Li(NMP)CN]
(298 K)
[Li(NMP)CN]
(100 K)
Formula
MW /g·mol–1
Space group (no.)
a /Å
b /Å
c /Å
LiC6H9 ON2
132.9
Pbca (61)
18.9954(3)
18.0036(3)
8.6802(2)
90
LiC6H9ON2
132.9
Pbca (61)
19.1275(7)
17.5813(5)
8.6021(2)
90
Notice: Slow evaporation of the solvent of the reaction mixture of 3-
bromocyclohexene and LiCl/NaCN/NMP yielded single crystals,
which are composed of 2LiBr·2LiCl·4NMP·4H2O.
α /°
β /°
90
90
3-Bromocyclohexene: 13C NMR (100 MHz, [D8]thf, 25 °C): δ = 18.6,
24.8, 32.8, 49.2, 129.0, 131.2 ppm.
γ /°
90
90
2892.8(8)
16
V /Å3
2968.5 (8)
16
Z
ZЈ
2
1.18
298
Cu-Kα1
1.5406
2
100
3.56
2.93
1.21
9.48
9.22
2
1.21
100
Cu-Kα1
1.5406
2
100
3.41
3.14
1.09
18.87
15.18
13.97
3-Cyanocyclohexene: 13C NMR (125.7 MHz, [D8]thf): δ = 19.1, 24.2,
26.3, 26.5, 120.8, 121.5, 131.8 ppm.
Dcalc /Mg·m–3
Temperature /K
Radiation type
Wavelength /Å
2θmin /°
2θmax /°
Rwp /%
Crystal Structure Determinations of [Li(Me2CO3)CN],
[Li(Et2CO3)CN], [Li(NMP)CN], and 2LiBr·2LiCl·4NMP·4H2O:
Data collections for [Li(Me2CO3)CN], [Li(Et2CO3)CN], and
2LiBr·2LiCl·4NMP·4H2O were performed with a STOE IPDS-II two-
circle diffractometer with Mo-Kα-radiation (λ = 0.71073 Å). The struc-
tures were solved with direct methods and refined against F2 by full-
matrix least-squares calculations. Absorption corrections were per-
formed with the MULABS option in PLATON.[14,15] All non-hydrogen
atoms were refined anisotropically, whereas the hydrogen atoms were
treated with a riding model.
Rexp /%
gof
RpЈa) /%
R
wpЈa) /%
a)
RR
Ј
/%
7.60
exp
a) RpЈ, RwpЈ and RexpЈ according to TOPAS.[16]
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Zeitschrift für anorganische und allgemeine Chemie
21, p. 340; N. Wiberg, Holleman-Wiberg, Lehrbuch der Anorgan-
ischen Chemie, 102.ed., de Gruyter, Berlin, 2007, p. 1259.
[2] U. Wietelmann, Sci. Synth. 2005, 8a, 139.
[3] K. Xu, Chem. Rev. 2004, 104, 4304; C. Angell, W. Xu, X. Sun,
US Patent 7,012,124, 2006.
Refinements of the low-temperature data at 100 K with TOPAS con-
firmed the structure of the compound. The values of RpЈ, RwpЈ and
expЈ are higher than for the ambient data, due to a new powder sample
(lower count rate; higher amount of amorphous material (see Table 2
and Supporting Information).
R
[4] J. L. R. Subramanian, Sci. Synth. 2004, 19, 173.
[5] M. C. DeLong, F. Rosenberger, J. Cryst. Growth 1986, 75, 164.
[6] K. Rossmanith, Monatsh. Chem. 1965, 96, 1691.
[7] J. W. Grate, I. B. Johns, H. R. DiPietro, J. Org. Chem. 1964, 29,
1970; K. Mai, G. Patil, J. Org. Chem. 1986, 51, 3545.
[8] J. T. Livinghouse, Org. Synth. 1990, 7, 117.
[9] J. A. Ciaccio, M. Smrtka, W. A. Maio, D. Rucando, Tetrahedron
Lett. 2004, 45, 7201.
[10] E. Bernhardt, M. Berkei, H. Willner, M. Schürmann, Z. Anorg.
Allg. Chem. 2003, 629, 677; E. Bernhardt, M. Finze, H. Willner,
Z. Anorg. Allg. Chem. 2003, 629, 1229.
[11] T. Afroz, D. M. Seo, S.-D. Han, P. D. Boyle, W. Henderson, J.
Phys. Chem. C 2015, 119, 7022.
[12] T. J. Markley, B. H. Toby, R. M. Pearlstein, D. Ramprasad, Inorg.
Chem. 1997, 36, 3376.
[13] S. Harusawa, R. Yoneda, Y. Omori, T. Kurihara, Tetrahedron Lett.
1987, 28, 4189.
[14] A. L. Spek, Acta Crystallogr., Sect. D 2009, 65, 148.
[15] G. M. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112; A. L.
Spek, Acta Crystallogr., Sect. D 2009, 65, 148.
Crystallographic data (excluding structure factors) for the structures in
this paper have been deposited with the Cambridge Crystallographic
Data Centre, CCDC, 12 Union Road, Cambridge CB21EZ, UK. Copies
of the data can be obtained free of charge on quoting the depository
numbers CCDC-1423161 ([Li(Me2CO3)CN]), CCDC-1423160
([Li(Et2CO3)CN]), CCDC-1458458 ([Li(NMP)CN]), CCDC-1504932,
([Li(NMP)CN] @ 100 K), and CCDC-1423162 (2LiBr·2LiCl·4NMP·
4H2O) (Fax: +44-1223-336-033; E-Mail: deposit@ccdc.cam.ac.uk,
http://www.ccdc.cam.ac.uk).
Supporting Information (see footnote on the first page of this article):
DTA/TG of [Li(NMP)CN] in N2 atmosphere. X-ray powder diffractog-
ram from a sample of [Li(NMP)CN] after DTA (300 °C in a N2 atmo-
sphere, cf. Figure S1). DTA/TG curve of [Li(NMP)CN] in air. X-ray
powder diffractogram from a sample of [Li(NMP)CN] after DTA
(300 °C, in air, cf. Figure S3). Rietveld Plot of [Li(NMP)CN] (298 K).
Rietveld Plot of [Li(NMP)CN] (100 K).
[16] A. A. Coelho, TOPAS-4.2, Coelho Software, Brisbane, Australia,
2009.
Acknowledgements
[17] WINXPOW, STOE & Cie GmbH, Darmstadt, Germany, 2009.
[18] A. Boultif, D. Louër, J. Appl. Crystallogr. 1991, 24, 987.
[19] D. W. M. Hofmann, Acta Crystallogr., Sect. B 2002, 58, 489.
[20] W. I. F. David, K. Shankland, J. van de Streek, E. Pidcock,
W. D. S. Motherwell, J. C. Cole, J. Appl. Crystallogr. 2006, 39,
910.
This work was supported by Merck KGaA, Darmstadt, Germany.
References
[1] U. Wietelmann, R. J. Bauer, Lithium and Lithium Compounds,
Ullmann’s Encyl. Industr. Chem. Wiley-VCh, Weinheim, 2012,
Received: June 23, 2016
Published Online: ᭿
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A. Budanow, K.-D. Franz, H. Vitze, L. Fink, E. Alig,
M. Bolte, M. Wagner, H.-W. Lerner* ............................... 1–8
Lithium Cyanide Supported by O- and N-Donors
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