Synthesis, structure, and thermal properties of fluorinated cesium beta-diketonates

Article abstract of DOI:10.1080/00958972.2013.801465

Four fluorinated cesium beta-diketonates, Cs(CF3COCHCOCF3) (Cs(hfac)), Cs(CF3COCHCOCH3) (Cs(tfac)), Cs(OH₂)((Me)3CCOCHCOCF3) (Cs(OH ₂)(ptac)), and Cs(OH₂)(PhCOCHCOCF3) (Cs(OH ₂)(btfac)), were synthesized by inte

Full text of DOI:10.1080/00958972.2013.801465

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Synthesis, structure, and thermal
properties of fluorinated cesium beta-
diketonates
Eugenia S. Vikulova a , Kseniya V. Zherikova a , Natalia V.
Kuratieva a , Natalia B. Morozova a & Igor K. Igumenov a
a Nikolaev Institute of Inorganic Chemistry Siberian Branch of the
Russian Academy of Sciences , Novosibirsk , Russian Federation
Published online: 11 Jun 2013.
To cite this article: Eugenia S. Vikulova , Kseniya V. Zherikova , Natalia V. Kuratieva , Natalia
B. Morozova & Igor K. Igumenov (2013) Synthesis, structure, and thermal properties of
fluorinated cesium beta-diketonates, Journal of Coordination Chemistry, 66:13, 2235-2249, DOI:
10.1080/00958972.2013.801465
To link to this article: http://dx.doi.org/10.1080/00958972.2013.801465
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Journal of Coordination Chemistry, 2013
Vol. 66, No. 13, 2235–2249, http://dx.doi.org/10.1080/00958972.2013.801465
Synthesis, structure, and thermal properties of fluorinated
cesium beta-diketonates
EUGENIA S. VIKULOVA*, KSENIYA V. ZHERIKOVA, NATALIA V. KURATIEVA,
NATALIA B. MOROZOVA and IGOR K. IGUMENOV
Nikolaev Institute of Inorganic Chemistry Siberian Branch of the Russian Academy of
Sciences, Novosibirsk, Russian Federation
(Received 26 June 2012; in final form 6 February 2013)
Four fluorinated cesium beta-diketonates, Cs(CF3COCHCOCF3) (Cs(hfac)), Cs(CF3COCHCOCH3)
(Cs(tfac)), Cs(OH2)((Me)3CCOCHCOCF3) (Cs(OH2)(ptac)), and Cs(OH2)(PhCOCHCOCF3)
(Cs(OH2)(btfac)), were synthesized by interaction of the corresponding beta-diketone and Cs2CO3 in
Et2O. The formation of Сs(CF3C(OH)2CH2C(OH)2CF3)(CF3COO) or Cs(CF3C(OH)2CH2COCH3)
(tfac) was shown to be dependent on the reaction conditions. The compounds were characterized by
elemental analysis, single crystal X-ray diffraction, and TG/DTA analysis.
All compounds have ionic structures organized into pseudo chains (in the case of Cs(hfac) and
Cs(CF3C(OH)2CH2COCH3)(tfac)) or pseudo layers (in other cases). According to the TG data
Cs(hfac), Cs(tfac), Cs(OH2)(ptac,) and Cs(OH2)(btfac) decompose in inert atmosphere within the
temperature range 30–550 °C.
Keywords: Cesium; Beta-diketonates; Single crystal X-ray analysis; Thermogravimetry; Differential
thermal analysis
1. Introduction
The introduction of cesium-containing dopants into oxide film materials causes improve-
ment of electric and electron functional characteristics. Thus, doping tin oxide films with
cesium substantially improves electric conductance and sensor response to Liquefied
Petroleum Gas [1]. According to a review [2], magnesium oxide films doped with cesium
possess larger secondary electron emission coefficients than non-doped ones.
Film materials can be successfully formed by Chemical Vapor Deposition from the vola-
tile metal compounds with organic ligands (MOCVD). The basic problem limiting the
usage of cesium as a film dopant is the absence of suitable cesium compounds satisfying
MOCVD requirements. The most important of the latter is volatility as a sufficiently high
vapor pressure at relatively low temperatures.
Compounds with molecular structures are known to have high volatility since the energy
of molecular interaction in their crystal lattices is very low, but very few cesium compounds
with molecular structures are known [3] due to Cs+ small charge and large radius, and
consequently, high coordination numbers (>8), as well as a tendency to form ionic bonds.
*Corresponding author. Email: lazorevka@mail.ru
Ó 2013 Taylor & Francis

2236
E.S. Vikulova et al.
Nevertheless, volatile ionic bimetallic cesium-containing compounds Cs[MLn] where
n = 4, M = Sc [4], or Y [4a, 5], L= hfac (CF3COCHCOCF3); M = Ho [6] or UO [7], L= ptac
(Me)3CCOCHCOCF3, or n = 3, M = Co, Ni, etc. [8], L= hfac, tfac (CF3COCHCOCH3),
acac (CH3COCHCOCH3) were described. Many of the compounds mentioned above sub-
lime from 150 to 250 °С.
Compounds for synthesis of cesium-containing complexes are cesium beta-diketonates
[4, 5, 8]. Combination of cesium beta-diketonate with bulky neutral ligands such as for
example, crown ethers, would produce a molecular crystal structure and possess sufficient
volatility. Similar compounds have been obtained for sodium and potassium [9].
The successful use of cesium beta-diketonates as reagents requires knowledge of chemi-
cal and thermal properties. However, little work on the synthesis of such compounds is
reported [10]; moreover, data on the structures and chemical properties of these
compounds are absent.
The goal of the present work is the synthesis of fluorinated cesium beta-diketonates and
investigation of the structures and thermal properties of the compounds obtained.
2. Experimental
2.1. Synthesis
All chemicals were commercially available products of reagent grade and used without
purification.
Cesium β-diketonates were obtained by reaction of Cs2CO3 with corresponding beta-
diketone in Et2O. A weighed portion of cesium carbonate was placed in an Erlenmeyer
flask equipped with a backflow condenser with a calcium chloride tube, and then Et2O and
beta-diketone were added. The reaction mixture was stirred at fixed temperature for a
certain time. Experimental details (time, temperature, reagent proportions) are presented
below. The product, if precipitated, was separated by filtration, otherwise – by evaporation
of the solution.
The substances were white powders stable during storage under ambient conditions.
Cesium (1,1,1,5,5,5-hexafluoroacetylacetonate) (1) was obtained from 2.60 g Cs2CO3
(8.0 mM) and 3.33 g Hhfac (2.4 mL, 16.0 mM) in 25 mL Et2O under 4 h at RT (25 °С).
Then the solution was evaporated yielding 4.60 g (13.5 mM) Cs(hfac), yield 84%. Anal
Calcd for C5H1F6O2Cs(%): С, 17.7; H, 0.3; F, 33.5. Found: С, 18.1; H, 0.2; F, 33.5.
Cesium (1,1,1,5,5,5-hexafluoropenta-2,2,4,4-tetraol)(1,1,1-trifluoroacetate) (2) was obtained
from 2.60 g Cs2CO3 (8.0 mM) and 5.60 g Hhfac (4.0 mL, 27.0 mM) in 50 mL Et2O under
10 h reflux (35 °С). The precipitated product was separated to give 3.46 g Cs(hfac)
(10.2 mM), while evaporation of the mother liquid yielded 3.04 g of the crude product.
Recrystallization of the latter from Et2O afforded crystals of 2 and also 1,1,1,5,5,5-hexaflu-
oropenta-2,2,4,4-tetraol (H4hfpt).
Cesium (1,1,1-trifluoroacetylacetonate) (3) was obtained from 2.85 g Cs2CO3 (8.7 mM)
and 2.68 g Htfac (1.9 mL, 17.4 mM) in 45 mL Et2O under 4 h reflux (35 °С). Then the
solution was evaporated yielding 3.00 g (10.5 mM) Cs(tfac), yield 60%. Anal Calcd for
C5H4F3O2Cs(%): С, 17.7; H, 0.3; F, 33.5. Found: С, 18.1; H, 0.2; F, 33.5.

Fluorinated cesium beta-diketonates
2237
Cesium (5,5,5-trifluoropentanediol-4,4-on-2)(1,1,1-trifluoroacetylacetonate) (4) was
obtained from 3.21 g Cs2CO3 (9.9 mM) and 4.58 g Htfac (3.3 mL, 29.7 mM) in 40 mL
Et2O under 3.5 h reflux (35 °С). The resulting solution was evaporated to give solid prod-
uct (6.60 g). Recrystallization from Et2O yielded crystals 4. Compound 4 was unstable at
atmosphere conditions.
Cesium aqua (pivaloyltrifluoroacetonate) (5) was obtained from 2.60 g Cs2CO3 (8.0 mM)
and 3.15 g Hptac (2.3 mL, 16.0 mM) in 55 mL Et2O under 6 h reflux (35 °С). The precipi-
tated product was separated by filtering to give 3.92 g Cs(OH2) (ptac) (11.3 mM). Anal
Calcd for C8H12F3O3Cs(%): С, 27.8; H, 3.5; F, 16.5. Found: С, 27.9; H, 4.0; F, 17.0.
Cesium (benzoyltrifluoroacetonate) and Cesium aqua (benzoyltrifluoroacetonate) (6) were
obtained from 1.30 g Cs2CO3 (4.0 mM) and 1.95 g Hbtfac (9.0 mM) in 30 mL Et2O under 2 h
reflux (35 °С). The precipitate (2.25 g) separated by filtering was a mixture of Cs(OH2) (btfac)
and Cs(btfac) at the ratio of 37 : 63 (per 100%). Anal Calcd for C10H6.7F3O2.5Cs(%): С, 33.8;
H, 1.9; F, 16.0. Found: С, 33.9; H, 1.7; F, 16.1.
2.2. Methods of characterization
Crystals suitable for single crystal X-ray diffraction analysis were obtained by slow crystal-
lization of the synthesized substances from organic solvents: Et2O for 1–4 and acetone for
5 and 6. Suitable single crystals were mounted on a Bruker Nonius X8 Apex 4 K CCD
diffractometer fitted with graphite monochromated Mo-Kα radiation (λ = 0.71073 Å). The
data were collected at 150 K for all structures by standard technique [11]. Absorption cor-
rections were made empirically using SADABS [11]. The structures were solved by direct
methods and further refined by full-matrix least-squares using the SHELXTL program
package [12]. Hydrogen positions were calculated geometrically and refined in the rigid
body approximation (riding model). Crystal data and the final refinement details are given
in table 1. The packing diagrams were drawn using the POV-Ray program package [13].
Elemental analysis was carried out at the Vorozhtsov Novosibirsk Institute of Organic
Chemistry SB RAS [14a,b]. The amount of fluorine was determined according to the
procedure for measurement of the mass fraction of fluorine in organic substances using the
spectrophotometric method [14c]. The error of determination did not exceed 0.5%.
Thermogravimetry (TG) and Differential Thermal Analysis (DTA) data for 1, 3, 5 and
mixture of Cs(btfac) and 6 were obtained using thermoanalizator Netzsch STA 409 PC/
PG. The experiments were conducted in He flow (20 mL minꢀ1) with heating rate
10 K minꢀ1 from 298 to 883 K. Products of thermal decomposition in an inert atmosphere
at 600 °C were amorphous so that no phase identification by XRD was possible.
Melting points of the compounds were determined visually using a Kofler table.
3. Results and discussion
3.1. Synthesis
The synthesis of cesium beta-diketonate was carried out through the substitution of
carbonate by beta-diketonate in diethyl ether. Reaction temperature and molar ratios of the
reagents have a dramatic influence on the process.

2238
E.S. Vikulova et al.

Fluorinated cesium beta-diketonates
2239
Cs(hfac) (1) was successfully obtained by reaction of Cs2CO3 and Hhfac in molar ratio
1 : 2 at room temperature. Boiling of these reagents in Et2O in the presence of 50% molar
excess of Hhfac gave the precipitate of 1; the ether solution contained H4hfpt and
Cs(CF3C(OH)2CH2C(OH)2CF3)(CF3COO) (2). Evaporation of the solvent and recrystalli-
zation from Et2O led to mixture of H4hfpt and 2. The compounds obtained were
characterized by single crystal X-ray analysis; the structure of H4hfpt had been earlier
described [15].
The possible reason for H4hfpt formation is the nucleophilic addition of water to the
carbonyl groups of Hhfac [16]. The formation of trifluoroacetate is likely to occur as a con-
sequence of Hhfac hydrolysis in the basic medium [17]. The water hydrating beta-diketones
may be present in diethyl ether or/and from air during evaporation of mother solution.
Stoichiometric amount of water is formed in situ due to the reaction Cs2CO3 + 2 Beta-
diketone = 2 Cs(beta-diketonate) + CO2 + H2O. These water molecules can react with the
ligands or can be coordinated by Cs.
The boiling of 1,1,1-trifluoroacetylacetone with Cs2CO3 at the ratio of 2 : 1 yielded
cesium trifluoroacetylacetonate (3) only, while the same reaction in the presence of a 50%
excess of the ligand led to the formation of Cs(CF3C(OH)2CH2COCH3)(tfac) (4). The
latter was unstable under storage and 5,5,5-trifluoropentanediol-4,4-on-2 formed during
decomposition of 4 was easily removed by washing with nonpolar solvent such as toluene
or hexane giving Сs(tfac) (3).
The selectivity of water nucleophilic addition to carbonyl of 3 can be explained in terms
of the negative inductive effect of CF3 such that carbon at position С2 is favored towards
nucleophilic attack.
The boiling of pivaloyltrifluoroacetone and Cs2CO3 at a ratio of 2 : 1 in Et2O led to for-
mation of a stable phase of cesium aqua pivaloyltrifluoroacetonate (5).
The interaction of benzoyltrifluoroacetone and Cs2CO3 under similar conditions gave a
mixture of cesium benzoyltrifluoroacetonate Cs(btfac) and cesium aqua benzoyltrifluoroacet-
onate Cs(OH2)(btfac) (6) at a ratio of 63 : 37 according to TG data (see thermogravimetric
examination) and elemental analysis data. Attempts to obtain Cs(btfac) crystals suitable for
XRD had no success; only Cs(OH2)(btfac) (6) single crystals were observed. Thus, water
presence is required to form good-quality crystals (see single-crystal XRD examination). It
should also be noted the crystals of 6 were unstable during storage and sensitive to illumina-
tion (visible light, X-rays). In our opinion, the destruction was connected with the detachment
of crystallization water (see thermogravimetric examination).
3.2. Single-crystal XRD examination
All the structures show ionic character with different ionic arrangement. The crystal pack-
ing, Cs…O and Cs…F distance ranges, and average lengths are listed in table 2.
Cs(hfac) (1). Cesium hexafluoroacetylacetonate crystallizes in the triclinic crystal system.
There are two independent cations in the structure. The nearest environment of Cs1 and
Cs2 consists of 11 and 12 O and F atoms, respectively. The first coordination sphere is six
and seven for Cs1 and Cs2, respectively. Zigzag bands consisting of Cs cations are located
along the a-axis. These bands are linked with longer Cs…F contacts. If one selects the lines
coinciding with the anion directions (O…O direction for example) these lines for all organic
anions are collinear within 4.4°. The shortest distance between Cs cations (Cs1…Cs2) is
4.2000(3) Å. The pseudo chain structure is represented at figure 1.

2240
Table 2. Selected Cs–O and Cs–F distances and crystal packing for 1–6.
Distance Cs–O, Å Distance Cs–F, Å
E.S. Vikulova et al.
Average
value
Average
value
Compound
Range
Range
Dimensionality⁄⁄
1-D
Cs(hfac) (1)
3.041(2)–3.407(2)
2.9918(13)–3.4518(12)
3.0346(14)–3.4934(14)
3.038(2)–3.325(2)
3.2h1i
3.2h2i
3.2h2i
3.16h8i
3.255(2)–3.722
(2)
3.4h2i
3.4h2i
3.3h2i
3.5h3i
3.26h5i
3.27h7i
Cs(H4hfpt)
(CF3COO) (2)
Cs(tfac) (3)
3.2022(13)–
3.6870(17)
3.0242(14)–
3.5119(12)
3.214(3)–3.750
(2)
2-D
2-D
1-D
2-D
2-D
Cs(H2tfpd)(tfac)
(4)
Cs(OH2)(ptac) (5)
3.094(3)–3.547(2)3.063
(3)–3.554(3)⁄
3.2h2i3.3h2i⁄ 3.194(2)–3.300
(3)
Cs(OH2)(btfac)
(6)
3.038(4)–3.249(5)2.990
3.18h9i
3.209(5)–3.323
(6)–3.063(6)⁄
3.03h4i⁄
(4)
⁄The distances Cs…OH2.
⁄⁄1-D = pseudo chain structure, 2-D = pseudo-layered structure.
Cs(CF3COO)(CF3C(OH)2CH2C(OH)2CF3) (2). The synthesis of
1
under modified
conditions resulted in formation of a new compound 2 containing an unusual form of
beta-diketone. In this compound, hexafluororoacetylacetone is hydrated on both carbonyl
groups, and anion is CF3COO–. Cs cation has four CF3C(OH)2CH2C(OH)2CF3 (H4hfpt)
species and three trifluoroacetate-anions. Coordination number of Cs atom is 12: six
oxygens belonging to three OH of three H4hfpt and three trifluoroacetates, and six
fluorines from four H4hfpt and two trifluoroacetates (figure 2). The whole structure is
pseudo-layered with alternating organic anionic layers and cationic Cs spaces. The shortest
distance between the Cs cations is Cs1…Cs1 (2 – x, ꢀy, 2 – z) of 4.5937(2) Å. The hexago-
nal distorted framework in Cs arrangement could be marked out in the structure.
Bond lengths and angles in H4hfpt (either free state [15] or cocrystallizate 2) or its
anionic forms (consisting of complexes [15b, 16]) do not change significantly during
formation of M–F contacts and M–O bonds or contacts.
The angle values and C–C and C–F bond lengths of CF3COOꢀ of 2 and
CsH(CF3COO)2 [18] are almost equal. The C–O distances in CF3COOꢀ of 2 are (1.226(2)
and 1.265(2) Å), while the longer bond refers to oxygen with two H-bonds.
Cs(tfac) (3). Pseudo-layered structure is observed for cesium trifluoroacetylacetonate. The
layers are located into the bc planes with the gap between them referring to the a parame-
ter. The first coordination sphere of Cs consists of seven oxygens and three fluorines
belonging to five trifluoroacetylacetonates. Cs cations form zigzag distorted hexagonal
grids inside the pseudo layers. Flat trifluoroacetylacetonates form the herringbone parquet
pattern below and above the cationic layer. The shortest distance between Cs cations is
Cs1…Cs1 (1 – x, ꢀy, ꢀz) at 3.9532(2) Å.
Cs(CF3C(OH)2CH2COCH3)(tfac) (4). Unlike the structure of 2, this compound contains
beta-diketone hydrated at only one carbonyl group (CF3C(OH)2CH2COCH3, H2tfpd) as a
cocrystallite. There are two crystallographically independent Cs cations in the unit cell.
Both have eight oxygens and two fluorines belonging to three trifluoroacetylacetone anions
and two H2tfpd (figure 3). Despite changes in γ-carbon’s hybridization, the plane is
preserved through the carbons in H2tfpd. Crystal packing gives the pseudo chain type. The

Fluorinated cesium beta-diketonates
2241
Figure 1. Example of pseudo chain structure for Cs(hfac) (1). Interactions between Cs cations and O or F of
anions are not depicted for simplification.
anions organize such that zigzag channels with negatively charged walls consisting of
carbonyl or hydroxyl groups are formed along the b-axis. The shortest distances between
the Cs cations are Cs1…Cs1 (1/2 – x, y + 1/2, 1/2 – z) of 4.1402(3) Å and Cs2…Cs2 (3/2 – x,
1/2 + y, 1/2 – z) at 4.2432(3) Å in the zigzag chains.
Table 3 presents the bond lengths for tfac, H2tfpd, and tfpd of 3, 4, and
Sb(p-PhCl)3(tfpd) [19].
Bond length and angle values of tfac anion in 3 and 4 are practically equal. Thus, the
presence of H2tfpd in 4 reorganizing the crystal structure does not influence the geometric
characteristics of tfac. For tfac structure Сγ–Сβ bond is a bit shorter than Сγ–Сδ, while
Cβ–Cα is a bit longer than Cδ–Cɛ (for atom numeration, see figure 4). This is the
characteristics of unsymmetrical beta-diketonates containing CF3 [20].
The addition of water to tfac anion causes the following structure changes as a result of
ρ-π conjugation loss and redistribution of electron density; while Cβ–Cα and Cδ–Cɛ bond
lengths remain practically the same Сγ–Сβ and Сγ–Сδ bond lengths become longer and
elongation of Сγ–Сβ bond is increased.
Structure comparisons of protonated (4) and deprotonated (in Sb(p-PhCl)3(tfpd) [19])
H2tfpd show practically all geometric parameters of the gem-diol persist in both ionic and

2242
E.S. Vikulova et al.
Figure 2. The nearest Cs+ environment in the structure of 2.
coordination compounds. Only the O–C–O angle makes an exception (112.6(2)° in 4 and
103.8° in Sb(p-PhCl)3(tfpd) [19]).
Cs(OH2)(ptac) (5). Cesium pivaloyltrifluoroacetonate cocrystallizes with water. There are
two independent formula units in the structure. Two Cs cations have β-diketonate anionic
and aqueous environment with shortest contact with the negatively charged O and F. Each
cation consists of four anionic species and three water molecules such that every Cs has
10 neighboring electronegative atoms in the coordination sphere (see figure 5). The short-
est distance between Cs cations is 4.2346(3) Å. There is a pseudo-layered arrangement of
cationic–anionic parts inside the crystal structure. The pseudo layer directions coincide
with the planes’ family (101). Cs ions form distorted square network into the pseudo layer.
The interlayer space is occupied with the tert-butyl substitutes of β-diketonate anions.
Cs(OH2)(btfac) (6). Compound 6 also cocrystallizes with one water molecule. There are
two independent Cs cations in the structure. Cs1 has eight oxygens from four beta-diketo-
nates in the vertices of a square antiprism and Cs2 is surrounded by four fluorines of four
beta-diketonates and four water molecule (see figure 6). Crystal packing represents a
pseudo-layered structure (see figure 7). The shortest distance between Cs cations is 4.2092
(2) Å. All Cs cations form nearly square frameworks.

Fluorinated cesium beta-diketonates
2243
Figure 3. The nearest environment of one of the independent Cs cations in 4.
Table 3. Bond lengths of tfac, H2tfpd and tfpd species in 3, 4, and Sb(p-PhCl)3(tfpd) [19]. Numeration of
carbons (α, β, etc.) corresponds to figure 4.
Bond length, Å
Cs(H2tfpd)(tfac) (4)
Bond
C=O
Cs(tfac) (3)
tfac
H2tfpd
Sb(p-PhCl)3(tfpd) [19]
1.2142(1)
1.253(2)
1.260(2)
–
1.252h4i
1.215h4i
C–O
–
1.396h9i
1.4019(1)
1.4321(1)
1.5351(2)
1.5119(1)
1.5300(1)
1.5094(2)
Cβ–Cα
1.545(2)
1.512(2)
1.380(2)
1.433(2)
1.551(4)
1.516h1i
1.392h3 i
1.416h4 i
1.538h3i
1.500h2i
1.528h1i
1.514h1i
Cδ–Cɛ
Сγ–Сβ
Сγ–Сδ
3.3. Comparison of structures presented
The range of beta-diketonates obtained allows us to compare structures of the carbon skeleton
t
depending on the substituent R (see figure 4). The change of R from CF3 to Me, Bu or Ph

2244
E.S. Vikulova et al.
Figure 4. Numeration of carbons in beta-diketonate-anions: tfac (R = Me), ptac (R = tBu), btfac (R = Ph). For
hfac (R = CF3), Cδ equals to Cβ and Cɛ to Cα are marked as Cβ and Cα, respectively.
Figure 5. The nearest Cs+ environment in 5. All hydrogens are omitted for simplicity. Oxygens of water are
depicted as balls and named Ow. Pendent CF3-groups belong to ptac anion.
causes symmetry loss of beta-diketonate, resulting in unequal carbon–carbon bond lengths.
The most striking difference is observed for R = Me and R = CF3 (see table 4).
For all compounds C–F bond lengths are 1.30–1.36 Å; average Cs–O and Cs–F dis-
tances are almost equal (see table 2).
All hydrogens of OH of 2 and 4–6 are engaged in formation of hydrogen bonds
(O–H…O) (see figure 8). There are either intra- or intermolecular hydrogen bonds in 2
and 4; average distances are 2.69 < 3 > Å for 2 (figure 8) and 2.73 < 5 > Å for 4. Every
oxygen in the beta-diketonate of 5 and 6 forms hydrogen bond with water; average

Fluorinated cesium beta-diketonates
2245
Figure 6. The nearest Cs+ environment in 6. All hydrogens are omitted for simplicity. Pendent CF3-groups
belong to btfac.
Ow…O distances are 2.79 < 3 > Å for Cs(OH2)(ptac) and 2.72 < 6 > Å for
Cs(OH2)(btfac).
Coordination numbers of cesium are 8–12 both for cesium beta-diketonates 1, 3, 5, 6,
and compounds including hydrated beta-diketones (2 and 4) from numerous Cs…O or
Cs…F interactions. Moreover, metal in beta-diketonates having bulky substituents (5 or 6)
add water molecules into the structure.
Comparison of cesium beta-diketonate structures with lithium and sodium ones [21] show
striking difference, obviously, as a result of great inequality in atomic radius and coordina-
tion number. Nevertheless, common features can be underlined. Any alkali metal contacts to
beta-diketonate by tetradentate bridge. For fluorinated beta-diketonates M–F contacts >3 Å
are also typical. Geometry of ptac remains unchanged for all known structures.
3.4. Thermogravimetric analyses
The thermal behavior of synthesized cesium beta-diketonates was studied by TG and DTA
from 25 to 600 °С. Experiments were carried out in the inert atmosphere (He) at the
constant heating rate (supplementary material).
A clear endothermic peak is observed in the DTA curve for 1 at 217 °С which corresponds
to melting (mp 220 °С, measured on Kofler table). At the same temperature the major mass
loss on the TG curve of 1 starts, demonstrating melting with decomposition. The compound

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E.S. Vikulova et al.
Figure 7. Pseudo-layered structure of Cs(OH2)(btfac) (6). Interactions between Cs and O or F of anions or water
are not depicted for simplification.
Table 4. C–C bond lengths of beta-diketonate-anions.
Bond length, Å
Bond
Cs(hfac) (1)
Cs(tfac) (3)
Cs(OH2)(ptac) (5)
Cs(OH2)(btfac) (6)
Cβ–Cα Cδ–Cɛ
Сγ–Сβ Сγ–Сδ
1.542h8i
1.400h9i
1.545(2) 1.512(2)
1.380(2) 1.433(2)
1.530h6i 1.535h2i
1.378h1i 1.439h3i
1.518(8) 1.495(8)
1.368(8) 1.439(8)
decomposes in two stages, the mass of the residue is 48.4% of the initial mass and it corre-
sponds to the formation of cesium carbonate (calculated for Cs2CO3 47.9%).
Cs(tfac) (3) melts with decomposition at 170 °С (mp measured is 169 °С). Decomposi-
tion proceeds in one stage and is accompanied by exoeffect. The mass of the residue is
66.8% of the initial.
Thermal decomposition of Cs(OH2)(ptac) (5) proceeds in two clearly separated steps.
The first involves detachment of water (mass loss is 4.9%, calculated for H2O 5.2%) which
is accompanied by an endothermic peak in the DTA curve. The next exoeffect at 105 °С
can be attributed to the phase transition, presumably caused by rearrangement of the struc-
ture due to water loss. The endoeffect at 170 °С corresponds to melting of Cs(ptac) (mp
measured is 175 °С) proceeding with decomposition similar to the case of previously
considered cesium beta-diketonates. Decomposition is over at 470 °С with formation of
cesium carbonate (mass of the residue is 47.1%, the value calculated for Cs2CO3 is 47.1%).
Thermal decomposition of the mixture of Cs(btfac) and Cs(OH2)(btfac) (6) also starts
from the endothermic detachment of water molecules (55–75 °С). The mass loss at the first
stage is 1.8% (calculated for Cs(OH2)(btfac): 4.9%), which corresponds to the ratio of
Cs(OH2)(btfac) to Cs(btfac) 37 : 63%. The results obtained are in agreement with the data

Fluorinated cesium beta-diketonates
2247
Figure 8. Example of H-bond structure for 2. Interactions between Cs and O or F of anions or waters are not
depicted for simplification.
of elemental analysis. The endo effect at 232 °С corresponds to Cs(btfac) melting (mp
measured is 228 °С). The major mass loss starts at 240 °С. The decomposition of Cs(btfac)
proceeds in two slightly separated stages, each accompanied by exoeffect. The mass of the
residue is 67.0% of Cs(btfac) mass.
4. Conclusion
Four cesium fluorinated beta-diketonates – cesium hexaflouroacetylacetonate, trifluoroace-
tylacetonate, pivaloyltrifluoroacetylacetonate, and benzoyltrifluoroacetylacetonate – have

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E.S. Vikulova et al.
been obtained by reaction of cesium carbonate and corresponding beta-diketone. The molar
ratio of reagents and the presence of water molecules have an influence on the final prod-
ucts. Cesium salts containing hydrated beta-diketones, Cs(CF3C(OH)2CH2C(OH)2CF3)
(CF3COO) and Cs(CF3C(OH)2CH2COCH3)(tfac), were formed at 50% ligand molar excess
of hexafluoroacetylacetone and trifluoroacetylacetone, respectively. Pure Cs(hfac) and
Cs(tfac) can be obtained using stoichiometric molar amounts of reagents. For Hptac
and Hbtfac, no hydration of ligands occurred; nevertheless, water molecules formed
Cs(OH2)(ptac) and Cs(OH2)(btfac), respectively.
Single crystal XRD analysis shows that crystal packing of Cs(hfac) and
Cs(CF3C(OH)2CH2COCH3)(tfac) can be represented by pseudo chain motifs, while the
structures of other salts form pseudo-layered ones. The links of chains (layers) are con-
nected through Cs…F and Cs…O interactions; oxygens of water in Cs(OH2)(ptac) and Cs
(OH2)(btfac) also interact with cesium.
All the cesium beta-diketonates investigated decompose during heating in the
temperature range 25–600 °C according to TG data. Destruction of Cs(OH2)(ptac) and
Cs(OH2)(btfac) begins with loss of water.
The results presented at this paper can be used as a basis for synthesis of more compli-
cated cesium-containing compounds.
Supplementary material
CCDC No. 888218 (1), 888215 (2), 888217 (3), 888216 (4), 888213 (5) and 888214 (6)
contain the supplementary crystallographic data. These data can be obtained via the
Cambridge Crystallographic Data Center (E-mail: deposit@ccdc.cam.ac.uk; www: http://
www.ccdc.cam.ac.uk/data_request/cif).
Acknowledgements
The work was supported by RFBR Grant No. 12-03-31277 mol_a.
References
[1] B. Thomas, S. Benoy, K.K. Radha. Sens. Actuators, B, 133, 404 (2008).
[2] A.M.E. Raj, M. Jayachandran, C. Sanjeeviraja. CIRP J. Manuf. Sci. Tech., 2, 92 (2010).
[3] (a) G.W. Rabe, L.M. Liable-Sands, C.D. Incarvito, K.-Ch. Lam, A.L. Rheingold. Inorg. Chem., 38, 4342
(1999); (b) S. Neander, U. Behrens, F. Olbrich. J. Organomet. Chem., 604, 59 (2000); (c) M. Hernández-
Arganis, S. Hernández-Ortega, R.A. Toscano, V. García-Montalvo, R. Cea-Olivares. Chem. Commun., 310
(2004).
[4] (a) M.Z. Gurevich, B.D. Stepin, V.V. Zelentcov. Zh. Neorg. Khim., 15, 890 (1970) (in Russian); (b) M.Z.
Gurevich, T.M. Sas, B.D. Stepin, N.E. Lebedeva. Zh. Neorg. Khim., 16, 2099 (1971) (in Russian).
[5] (a) S.J. Lippard. J. Am. Chem. Soc., 88, 4800 (1966); (b) M.Z. Gurevich, B.D. Stepin, V.V. Zelentcov. Zh.
Neorg. Khim., 15, 1996 (1970) (in Russian).
[6] R. Belcher, J. Majer, R. Perry, W.I. Stephen. J. Inorg. Nucl. Chem., 31, 471 (1969).
[7] G.V. Sidorenko, M.S. Grigor’ev, V.V. Gurzhiy, S.V. Krivovichev, D.N. Suglobov. Radiochemistry, 52, 382
(2010).
[8] (a) M.Z. Gurevich, T.M. Sas, N.E. Mazepova, V.V. Zelentcov, B.D. Stepin. Zh. Neorg. Khim., 20, 735
(1975) (in Russian); (b) A. Yu. Steblyanko, A.N. Grigor’ev, L.I. Martynenko. Russ. J. Inorg. Chem., 41, 565
(1996).
[9] (a) L.J. Farrugia, I.M. Watson. Acta Cryst., C55, 326 (1999); (b) D.M. Tsymbarenko, I.E. Korsakov, A.R.
Kaul, E. Kemnitz, S.I. Troyanov. Acta Cryst., E63, m2195 (2007).
[10] C.R. Bhattacharjee, M. Bhattacharjee, M.K. Chaudhuri, H. Sangchungnunga. J. Chem. Res. (S), 250 (1991).

Fluorinated cesium beta-diketonates
2249
[11] Bruker Advanced X-ray Solutions. APEX2 (Version 1.08), SAINT (Version 7.03), and SADABS (Version
2.11), Bruker AXS Inc., Madison, WI (2004).
[12] G.M. Sheldrick. Acta Crystallogr., A64, 112 (2008).
[13] Persistence of Vision Pty. Ltd. POV-Ray for Windows, Williamstown (2004). Available online at: http://www.
povray.org/ (accessed 1 June 2009).
[14] (a) V.P. Fadeeva, V.D. Tikhova, O.N. Nikulicheva. J. Anal. Chem., 63, 1094 (2008); (b) V.P. Fadeeva, V.D.
Tikhova, O.N. Nikulicheva, I.I. Oleynik, I.V. Oleynik. J. Struct. Chem. (Suppl.), 51, S188 (2010); (c) V.P.
Fadeeva, I.M. Moryakina. Izv. Sib. Otd. Akad. Nauk SSSR, Ser.: Khim., 6, 113 (1981) (in Russian).
[15] (a) A.N. Chekhlov. J. Struct. Chem., 40, 330 (1999); (b) E. Bouwman, K.G. Caulton, G. Christou, K. Fol-
ting, Ch. Gasser, D.N. Hendrickson, J.C. Huffman, E.B. Lobkovsky, J.D. Martin, P. Michel, H.-L. Tsai, Z.
Xue. Inorg. Chem., 32, 3463 (1993).
[16] (a) E. Bouwman, J.C. Huffman, E.B. Lobkovsky, G. Christou, H.-L. Tsai, D.N. Hendrickson. Inorg. Chem.,
31, 4436 (1992); (b) H. Zhang, J.-H. Yang, E.V. Dikarev. Dalton Trans., 39, 2484 (2010); (c) Z. Wie, J.-H.
Yang, V.D. Vreshch, A.V. Zabula, A.S. Filatov, E.V. Dikarev. Inorg. Chem., 50, 7295 (2011).
[17] M. Urrutigoïty, C. Cecutti, F. Senocq, J.-P. Gorrichon, A. Gleizes. Inorg. Chim. Acta, 248, 15 (1996).
[18] L. Golič, J.C. Speakman. J. Chem. Soc., 2530 (1965).
[19] F. Ebina, A. Ouchi, Y. Yoshino, S. Sato, Y. Saito. Acta. Cryst., B33, 3252 (1977).
[20] (a) T.M. Polyanskaya, G.V. Romananko, H.V. Podberezskaya. J. Struct. Chem., 38, 637 (1997); (b) S.A.
Gromilov, I.A. Baidina. J. Struct. Chem., 45, 1031 (2004); (c) K.V. Zherikova, N.V. Kuratieva, I.A. Baidina,
N.B. Morozova. J. Struct. Chem., 51, 769 (2010).
[21] (a) J.J. Sahbari, M.M. Olmstead. Acta Cryst., C39, 1037 (1983); (b) L. Salmon, P. Thuéry, M. Ephritikhnie.
Acta Cryst., E62, m1250 (2006); (c) N.S. Karpenko, V.I. Filyakova, G.G. Aleksandrov, V.N. Charushin.
J. Struct. Chem., 46, 955 (2005); (d) E.S. Filatov, I.A. Baidina, I.K. Igumenov. J. Struct. Chem., 47, 484
(2006).