ISMSC 2007 - Università degli Studi di Pavia

PSA 61
Piperazine Containing Polyamino and Polyamino-amido Receptors of Open-
Chain and Cyclic Topology
José M. Vistos, a J. M. Llinares, b Jorge González, a E. García-España, a C. Sorianob and K.
Rissanen. c
a) Departament de Química Inorgànica, Instituto de Ciencia Molecular, Facultat de
Química,Universitat de València.
b) Departament de Química Orgánica, Instituto de Ciencia Molecular, Universitat de València,
Burjassot.
c) Univ Jyvaskyla, Nanosci Ctr, Dept Chem, FIN-40014 Jyvaskyla, Finland
Piperazine moieties behave as reinforcing component when inserted into polyamine structures.
Their low energy-chair conformation usually favors the formation of macrocycles of large
size.1,2 Change from chair to boat conformation is an energy demanding step that usually
needs of the binding of appropriate guest species to the piperazine nitrogens. Alternatively, this
energetic barrier can be overcome in the synthetic procedure by connecting the piperazine rings
to appropriate building blocks.
Herewith we report on the synthesis and anion coordination capabilities of a series of new
polyamine or polyamine-amide open-chain and cyclic molecules having the tetraamine N,N’bis(aminopropyl)piperazine
and different aromatic spacers as basic constituents.
1) K. Rissanen, J. Huuskonen, A. Koskinen, J. Chem. Soc., Chem. Commun. 1993, 731.
2) J. A. Aguilar, E. García-España, J. A. Guerrero, J. M. Llinares, J. A. Ramírez, C. Soriano, S.
V. Luis, A. Bianchi, L. Ferrini, V. Fusi, J. Chem. Soc., Dalton Trans. 1996, 239-246
PSA 62
Cooperativity of inclusion by macrocyclic receptors for vapor sensing and
storage
Valery V. Gorbatchuk, Marat A. Ziganshin
Chemical Institute, Kazan State University, Kremlevskaya 18, 420008 Kazan, Russia
Cooperativity of inclusion observed in systems with solid receptors and substrate vapors
contributes much in their actual and possible applications. While used in vapor sensors,
clathrate-forming hosts have the additional selectivity linked to cooperative change of guest
inclusion threshold. The volatile substrates, when bound, are held in clathrates with crystal
cooperativity, which is important for gas storage. The inclusion properties of hydrophilic
receptors cooperatively depend on their hydration, which gives a guide for a design of
biomimetic and biocompatible organic hosts.
The present work provides experimental data on the above-mentioned and a number of other
practically useful effects related to the cooperativity of clathrate formation and decomposition for
such macrocyclic receptors as calixarenes and cyclodextrins. For example, the guest inclusion
threshold of tert-butylcalix[4]arene was found to decrease practically to zero in the presence of
small impurities of some other guests. This effect can be used to reduce the pressure threshold
for gas inclusion. Another possibility to reach this goal is to use receptor phase having loose
packing. Such stable materials with large pores of molecular size and a wide range of thermal
stability were prepared for several calixarene derivatives. The size and stability of pores are
tunable.
Another type of cooperative effects for solid macrocyclic receptors is clathrate memory. Being
caused by enhanced clathrate stability compared with the properties of liquid solutions, the
memory effects were observed for calixarenes in sensors. A simple regeneration technique was
offered together with its quantitative criteria.
Quantitative thermodynamic description is given for all observed cooperative phenomena, which
makes their prediction and understanding easy and comprehensive.
The inclusion cooperativity defines specific selectivity and molecular recognition in solid-phase
host-guest interactions.[1] Corresponding structure-property relationships for inclusion
parameters can be reasonable if clathrates compared have the same preparation history. In the
present work, the effect of host and guest structure on parameters of guest inclusion was
studied for a number of calixarenes under strictly the same conditions. Several simple
relationships were found, which may be used in a directed design of new macrocyclic receptors.
This work was supported by RFBR (05-03-33012) and BRHE (REC-007).
[1] M. A. Ziganshin, A. V. Yakimov, G. D. Safina, S. E. Solovieva, I. S. Antipin, and V. V.
Gorbatchuk Org. Biomol. Chem., 2007, 5, 1472 - 1478