Studies of reaction heats and structures of complexes formed between macro compounds and SbCl5 in CCl4

Article abstract of DOI:10.1016/S0022-2860(00)00464-6

The heats of reactions between the acyclic and cyclic macro-compounds are determined. The values can be used as a measure of the donor abilities of the macro ligands. Formation of two types of complexes between the macro compounds and SbCl₅ is

Full text of DOI:10.1016/S0022-2860(00)00464-6

Journal of Molecular Structure 526 (2000) 159–163
www.elsevier.nl/locate/molstruc
Studies of reaction heats and structures of complexes formed
between macro compounds and SbCl in CCl
5
4
a
a
b
a,*
G. Schroeder , B. Gierczyk , V. Rybachenko , B. Brzezinski
a
Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Pozna n´ , Poland
b
Institute of Physical Organic and Coal Chemistry, National Academy of Sciences, R. Luxemburg 70, 340114 Donetsk, Ukraine
Received 14 January 2000; accepted 11 February 2000
Abstract
The heats of reactions between the acyclic and cyclic macro-compounds are determined. The values can be used as a measure
of the donor abilities of the macro ligands. Formation of two types of complexes between the macro compounds and SbCl is
established. The acyclic macro-compounds form 1:1 complexes, whereas the macrocyclic compounds only 1:2 complexes.
2000 Elsevier Science B.V. All rights reserved.
5
᭧
Keywords: Reaction heat; Supramolecular chemistry; Macrocyclic compounds; Tris(oxaalkyl)-phosphates; Tris(oxaalkyl)-phosphines; Tris(ox-
aalkyl)-silanes; SbCl
5
1. Introduction
In this paper formation and structures of the
complexes of some cyclic and acyclic macro-
Recently, we have studied the complexation of
compounds with SbCl are studied by the calorimetric
5
some acyclic macro-compounds as well as crown
titration in the aprotic solvent, CCl4.
ϩ
ϩ
ethers with protons and cations such as Li , Na
ϩ
and K , by spectroscopic methods [1–9]. These
studies have demonstrated that within the complexes
all the cations fluctuate in multi-minima potentials
showing the so-called proton and cation polarisabil-
ities due to these fluctuations [10–14].
2. Experimental
Crown ethers and tris(3,6-diazaheptyl)amine were
used as commercial products (Aldrich). The esters of
inorganic acids: P(OR) and OP(OR) were prepared
It is well known that the enthalpy of the interaction
3
3
according to previously described procedures [17].
between SbCl (Lewis acid) electron donors (solvents
5
or atoms including free electron pair) makes the scale
of Gutmann’s Donor Numbers, DN [15,16]. The scale
is supplemented by the data obtained from C NMR
and the ionisation of the PhC–Cl bond in the
measured solvent.
2.1. Synthesis of phenyl-tris(oxaalkyl)silanes
1
3
Phenyl-tris(oxaalkyl)silanes were obtained in
reactions of phenyltrichlorosilane with a corre-
sponding poly(ethylene glycol) monomethyl ether.
To a solution of poly(ethylene glycol) monomethyl
*
Corresponding author. Tel.: ϩ 48-61-869-9181; fax: ϩ 48-61-
65-8008.
E-mail address: bbrzez@main.amu.edu.pl (B. Brzezinski).
3
ether (0.25 mol) in ethyl ether (100 cm ) cooled to
8
0ЊC, phenyltrichlorosilane (0.08 mol) was added
0
022-2860/00/$ - see front matter ᭧ 2000 Elsevier Science B.V. All rights reserved.
PII: S0022-2860(00)00464-6

1
60
G. Schroeder et al. / Journal of Molecular Structure 526 (2000) 159–163
Table 1
Boiling points and yields of phenyl-tris(oxaalkyl)silanes
Compound
Boiling point (ЊC/mmHg)
Yield (%)
92
1
2
2
81–183/1.2
45–247/1.1
55–258/0.2
Si(OCH CH OCH )
3 3
2
2
90
85
Si(OCH CH OCH CH OCH )
3 3
2
2
2
2
Si(OCH CH OCH CH OCH CH OCH )
3 3
2
2
2
2
2
2
dropwise over 2 h under continuous stirring. The
solvent was removed on a rotary evaporator. The
products were purified by vacuum distillation and
their purity was controlled by GC and NMR tech-
niques. The boiling points and yields are given in
Table 1.
procedure given in Refs. [18,19] by the titration of
macro-compounds with SbCl , both dissolved in CCl .
5
4
3. Results and discussion
The dependencies of the observed enthalpy on
CSbCl5/Cligand or Cligand/CSbCl5 for two examples of the
acyclic and cyclic macro-compounds (two types of
ligands) are shown in Fig. 1a and b, respectively. Fig.
1a shows that in the case of acyclic macro-compounds
2
.2. Calorimetric measurements
The reaction heats were determined following the
Ϫ3
Ϫ3
Fig. 1. Calorimetric titration curves for: (a) PhSi(OCH
CC1
2
CH
2
3
OCH )
3
ꢀ2 × 10 M† by SbC1
5
in CC1
4
; (b) cyclamene ꢀ2 × 10 M† by SbC1
5
in
4
.

G. Schroeder et al. / Journal of Molecular Structure 526 (2000) 159–163
161
Table 2
X
O
O
Heats of interactions of macro-compounds with SbCl
solution (1:1 complexes)
in CCl
-
5
4
O
Macro-compounds
ϪDH
(kJ mol
Cl
O
Cl
Ϫ1
O
)
Sb
O
Cl
Cl
O
Cl
P(OC
P[OCH
P[OCH
OyP(OC
OyP[OCH
H
)
108 ^ 5
188 ^ 4
265 ^ 9
102 ^ 5
118 ^ 7
132 ^ 9
143 ^ 16
2
5
3
2
CH
CH
2
2
5
OCH
3 3
]
O
O
2
2 2 3 3
OCH CH OCH ]
H3C
2
H
)
3
H C
3
CH3
2
2 3 3
CH OCH ]
OyP[O–(CH
OyP[O–(CH
2
CH
CH
2
O)
O)12CH
7
CH
3
]
3
1
:1 COMPLEX (X= P, O=P, Si or N)
]
2
2
3
3
181 ^ 6
Si(OCH CH OCH )
3 3
2
2
O
268 ^ 15
Cl
Si(OCH CH OCH CH OCH )
2 2 2 2 3 3
O
O
Cl
Sb Cl
Cl
O
O
Cl
Cl Sb
356 ^ 16
Cl Cl
Cl Cl
Si(OCH CH OCH CH OCH CH OCH )
2
2
2
2
2
2
3 3
O
N(CH
2
CH
2
OCH
2
CH
2
OCH
3
)
3
360 ^ 20
1
:2 COMPLEX
Scheme 1.
groups. Furthermore, for two types of ligands, i.e.
tris(oxaalkyl)phosphines and tris(oxaalkyl)silanes,
the DH values are comparable for the chains of
comparable lengths. The results indicate that the
lengths of oxaalkyl chains determine the complex
only 1:1 complexes with SbCl are formed. In the case
5
of cyclic macro-compounds only 1:2 complexes
(
Cl Sb ← Donor ! SbCl ) are formed (Fig. 1b). The
5
5
structures of these two types of complexes are shown
in Scheme 1.
formation between them and SbCl . Completely
5
different DH values were observed in the complexa-
tion reaction of tris(oxaalkyl)phosphates by SbCl5.
These values are much lower and the increase of
DH with increasing lengths of the chains is also
much lower, indicating the existence of an equili-
brium in which not only the chains, but also the
PyO bonds are ligands for the SbCl5 molecule
(Scheme 2 (the equilibrium in 1:1 complexes formed
The heats of the reactions between acyclic and
cyclic ligands with SbCl are summarised in Tables
5
2
and 3, respectively.
Table shows three families of ligands:
tris(oxaalkyl)phosphines, tris(oxaalkyl)phosphates
and tris(oxaalkyl)silanes. In each family, DH values
increase with increasing chain length of oxaalkyl
2
R
R
O
Cl
Cl
Cl
O
Cl
Cl
Cl
R
O
P=O
Sb
Cl
P=O
Sb
O
R
Cl
R
O
Cl
Cl
O
R
Scheme 2.

1
62
G. Schroeder et al. / Journal of Molecular Structure 526 (2000) 159–163
Table 3
5 4
Heats of interactions of macrocyclic compounds with SbCl in CCl solution (1:2 complexes)
Ϫ1
Ϫ1
Macrocyclic compound
ϪDH (kJ mol
32 ^ 6
)
Macrocyclic compound
ϪDH (kJ mol
240 ^ 10
)
2
O
O
O
O
O
O
O
O
O
O
O
O
2
4
57 ^ 10
278 ^ 10
O
O
O
O
O
O
O
O
O
O
O
O
05 ^ 10
410 ^ 15
HN
O
NH
O
O
O
O
NH
O
HN
3
84 ^ 14
336 ^ 10
NH HN
NH HN
NH HN
NH HN
between tris(oxaalkyl)phosphates and SbCl mole-
Research KBN, grant 3 TO9A 03413. Prof V.I. Ryba-
chenko also thanks the financial support of the J.
Mianowski Fund for Science Development in Poland.
5
cules)). The same is true in the case of cryptands.
Table 3 demonstrates that in the case of macro-
cyclic compounds including only five or six oxygen
atoms, the DH values of the formation of 1:2
complexes with SbCl molecules are comparable.
References
5
Thus, the number of the oxygen atoms does not play
an important role in the complexation.
In conclusion this paper is the first to report the
donor numbers of acyclic and cyclic macro-
compounds.
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[