STUDIA UNIVERSITATIS BABEŞ-BOLYAI, PHYSICA, SPECIAL ISSUE, 2003
SYNTHESIS AND CHARACTERISATION OF SOME NEW CALIX[n]ARENE
DERIVATIVES
Traian-Nicolae URSALEŞ1, Elisabeth-Jeanne POPOVICI1, Ioan SILAGHIDUMITRESCU2, Nicolae POPOVICI1 and Adina URSALEŞ1
1
"Raluca Ripan" Institute for Research in Chemistry,
Fantanele 30, PO Box 702, R- 3400 Cluj-Napoca;
e-mail: TUrsales@email.ro
2
Faculty of Chemistry and Chemical Engineering,
Babes-Bolyai University, R-3400 Cluj-Napoca, Romania
Abstract
The synthesis of new calix[n]arene derivatives was attempted by selective
alkylation with dichlorophenylphosphinoxide and 2-butenyl bromide, in
the presence of sodium hydride as a base. The results of FT-IR, 1H-NMR
and 31P-NMR spectroscopic investigations are in good agreement with the
expected structure and purity of such prepared material.
Keywords: calixarene, dichlorophenylphosphinoxide, E-2-butenyl
bromide, alkylation.
1. Introduction
Calix[n]arene are cyclic oligomers of phenol-formaldehyde condensates.
This class of compounds has generated a particular interest because of their natural
basket-shaped cavities associated with versatile recognition properties towards ions
and neutral molecules as well1-3. By selective functionalisation at the OH phenolic
groups (lower rim) and/or in the para positions of the phenol ring (upper rim),
specific receptors for cations4, anions5 and neutral molecules6 could be prepared.
With the purpose to obtain some new calixarenes derivatives with
increased ability to extract lanthanide ions, the selective alkylation of p-tertbutyl
calix[n]arenes with dichlorophenylphosphinoxide and 2-butenyl bromide was
attempted. The paper presents our results referring to the synthesis and
characterisation of some new compounds from this class.
2. Experimental part
The calixarene derivatives were prepared in the presence of sodium
hydride (NaH), by the reaction between calix[4],calix[6],and calix[8]arenes with E2-butenyl bromide (crotyl bromide) and dichloro-phenylphosphinoxide, in
acetonitril or dimethylformamide- tetrahydrofuran medium. The syntheses were
performed at reflux, under inert atmosphere. FT-IR (KBr pellets; JASCO-615
Spectrometer), 1H-NMR (tetramethylsilane; 80MHz Brucker Spectrometer) and
31
P-NMR (phosphoric acid; 200MHz Brucker Spectrometer) investigation methods
were used in order to check out the purity of as prepared products.
T.N URSALEŞ, E-J POPOVICI, I. SILAGHI-DUMITRESCU, N. POPOVICI and A.URSALEŞ
3. Results and discussions
The starting calixarenes were prepared by adapting the synthesis method
described in the literature7-9. The simultaneous alkylation of calixarenes with
dichlorophenilfosphin oxide and crotyl bromide give rise to some derivatives that
possess two types, of substituting groups at the lower rim (reaction 1).
(1.)
I. R = t-Bu; R’ = Crotyl; n = 1; m = 2; II. R = t-Bu; R’ = Crotyl; n = 1; m = 4;
III. R = t-Bu; R’ = Crotyl; n = 1; m = 6
Elemental analysis, 1H-NMR, 31P-NMR and FT-IR (figure 1-3)
investigations confirmed the formation of the new calix[n]arenes derivatives The
main characteristics of the new products are as follows:
Compound I
Elemental analysis: MW=862, calculated for C58H71O4P; C= 79.02 %; H= 8.49%,
P= 4.23 % found; C= 80.74 %; H= 8.24%, P= 3.59% calculated.
FT-IR: (KBr, cm-1); CH=CH: 3023.84 and 965.68 cm-1; P=O: 1201.43 cm-1; P-O-C:
970.00 cm-1; P-C: 694.25 cm-1;
1
H-NMR (ppm, CDCl3, ppm): 6.75-7.24(m, 13H, C6H2 and C6H5); 5.60-5.80(m, 4H,
CH=CH); 4.23-4.42(m, 8H, ArCH2Ar); 2.86-3.40(m, 4H, -OCH2); 0.69-1.78(m,
42H, =CH-CH3 and tBu).
31
P-NMR (ppm, CDCl3, ppm): 22.85; and –10.42 (2 s, 1P).
Compound II
Elemental analysis: MW=1294, calculated for C88H111O4P; C= 80.01 %; H= 8.69%,
P= 3.21 % found; C= 81,61 %; H= 8.57%, P= 2.39% calculated.
FT-IR: (KBr, cm-1): CH=CH: 3021.91 and 966.64 cm-1; P=O: 1203.36 cm-1; P-O-C:
955,64 cm-1; P-C: 694.98 cm-1;
1
H-NMR (ppm, CDCl3, ppm): 6.93-7,26(m, 17H, C6H2 and C6H5); 5.62(m, 8H,
CH=CH); 3.86(m, 12H, ArCH2Ar); 1.85(m, 8H,-OCH2); 1.55(d, 8H, 3JHH=7,12Hz);
1.26(s, 54H, tBu).
31
P-NMR (ppm, CDCl3, ppm): 22.62 (s, 1P).
Compound III
Elemental analysis: MW=1726, calculated for C118H151O4P; C= 81.79 %; H=
8.92%, P= 2.29 % found; C= 82.04 %; H= 8.75%, P= 1.79% calculated.
FT-IR: (KBr, cm-1): CH=CH: 3023.84 and 968.57 cm-1; P=O: 1204.81 cm-1; P-O-C:
947.84 cm-1; P-C: 693.28 cm-1;
1
H-NMR (ppm, CDCl3, ppm: 7.49(m, 5H, C6H5); 6.94(s, 16H, C6H2); 5.50(m, 12H,
CH=CH); 4.08(d, 8H, ArCH2Ar,3JHH=6,9Hz);3.72(d, 8H, ArCH2Ar, 3JHH= 7,08Hz);
2.70(m, 12H, -OCH2); 1.45(d, 18H, =CH-CH3, 3JHH=6,0Hz); 1.25(s, 72H, tBu).
31
P-NMR (ppm, CDCl3, ppm): 21.84 (1s, 1P).
SYNTHESIS AND CHARACTERISATION OF SOME NEW CALIX[n]ARENE DERIVATIVES
In the 1H-NMR spectra of the parent calixarenes, the OH group signals
appear at 9.5-10.2 ppm. The disappearance of the signals in the spectra of the new
derivatives confirmed the full functionalisation of the starting calixarenes.
Figure 1. FT-IR spectra of mono(phenylphosphinoxide)-bis(2-butenyl)-ptertbutylcalix[4]arene (I) (straight line) as compared with the original ptertbutylcalix[4]arene (dashed line).
Figure 2. Infrared spectra of mono(phenylphosphinoxide)-tetra(2-butenyl)-ptertbutylcalix[6]arene (II) ( straight line) as compared with the original ptertbutylcalix[6]arene (dashed line).
Figure 3. Infrared spectra of mono(phenylphosphinoxide)-hexa(2-butenyl)-ptertbutylcalix[8]arene (III) (straight line) as compared with the original ptertbutylcalix[8]arene (dashed line).
T.N URSALEŞ, E-J POPOVICI, I. SILAGHI-DUMITRESCU, N. POPOVICI and A.URSALEŞ
New signals at 5.5-5.8 ppm appeared, which were correlated with the
presence of the protons from the CH=CH groups of the crotyl groups. The protons
of -OCH2 and =CH-CH3 groups give signal at ~ 1.8-2.8 ppm and near the tert-butyl
protons, respectively. The protons from the phenylphosphinoxide bridge give broad
signals in the aromatic zone of the calixarene skeleton (6.7-7.5 ppm). The
phosphorus presence in the new compounds was put in evidence by the specific
signals (21.84-22.85 ppm) from the 31P-NMR spectra.
FTIR spectra revealed the disappearance of the OH groups from the parent
calixarenes. The specific OH vibrations of the p-tert-butylcalix[4]arene, p-tertbutylcalix[6]arene and p-tertbutylcalix[8]arene (3173, 3150 or 3140 cm-1,
correspondingly) could not been noticed in the spectra of the compound I, II or III.
New vibration bands for the substituting groups could be observed, namely:
1201.43 cm-1 (P=O), 970.00 cm-1 (P-O-C) and 3023.84 and 965.68cm-1 (crotyl
groups) for compound I; 1203 cm-1 (P=O), 956 cm-1 (P-O-C) and 3022 cm-1 and
967 cm-1 (crotyl groups) for compound II and 1201 cm-1 (P=O), 970 cm-1 (P-O-C),
and 3024 cm-1 and 966 (crotyl groups) for compound III.
4. Conclusions
The spectroscopic investigations confirmed the formation of calixarenes
derivatives containing one phenylphosphinoxide bridge group and 2, 4 or 6 crotyl
groups, respectively. These new compounds, which were not previously described
in the literature, possess large utilisation potential. The presence of “p” electrons
of the oxygen (P=O group) and π electrons (crotyl group) could increase the ability
of the new calixarene derivatives to extract rare-earth ions.
Acknowledgements:
The work was supported by CERES National Research Program, under contract no.
42/2001.
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