Send Orders for Reprints to reprints@benthamscience.ae Current Inorganic Chemistry, 2015, 5, 5-25 5 1877-945X/15 $58.00+.00 © 2015 Bentham Science Publishers Coordination Polymers and Oligonuclear Systems Based on Oximate or Hydroxamate Building Blocks: Magnetic and Sorption Properties A.V. Pavlishchuk 1 , Yu. A. Satska 2 , S.V. Kolotilov 2 and I.O. Fritsky 1,* 1 Department of Chemistry, Taras Shevchenko National University of Kyiv, Volodymyrska str. 62, Kiev 01601, Ukraine; 2 L.V.Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sci- ences of the Ukraine, Prospect Nauki 31, Kiev 03028, Ukraine Abstract: The review covers structures and properties of compounds, possessing porous crystal lat- tices, or coordination polymers, which are assembled on the basis of polynuclear oximate or hydrox- amate complexes of 3d metals. It is shown that magnetic properties of such systems are governed by the exchange interactions in the polynuclear building blocks and can be pre-determined by the appro- priate choice of starting compound. In contrast, the structure and topology of the framework, obtained on the basis of polynuclear oximate or hydroxamate, do not correlate with the quantity of vacancies in coordination spheres of metal ions in the starting compound, as well as they do not correlate with the quantity of ligand donor atoms. Some of the compounds, considered in this review, show ability to absorb different substrates. Such absorp- tion is different from "classical" filling of micropores; sorption capacity is governed by the energy of host-guest interac- tions rather than the volume of rigid micropores in crystal lattice. Keywords: Building block approach, coordination polymer, hydroxamate, magnetic properties, metallacrown, oxime, sorption properties. INTRODUCTION Interest in coordination polymers and discrete complexes of transition metals with porous lattices is motivated by wide possibilities of their use as selective sorbents [1-5], station- ary phases for analytical or preparative chromatography [6,7] (including separation of optical isomers [8-10,11], catalysts [12-16], magnetic [17,18] or luminescent [19-21] materials, as well as materials for non-linear optics [22]. Determination of factors which control certain physical or chemical proper- ties of such systems is an important task of modern inorganic and physical chemistry, as well as material science. Many studies were devoted to the development of methods for di- rected synthesis of systems, possessing desired properties [23]. However, in the vast majority of cases the structure of the compound, obtained as a result of reaction between metal ions and ligands, can not be predicted. Isoreticular synthesis is one of the few successful strategies, leading to compounds of similar (hence, predictable) topology, which is preserved in a row of isoreticular species [24]. The use of pre-synthesized polynuclear complexes as building blocks is the second example of successful assem- bly of compounds with desired topology [25-31]. The advan- tage of this approach is an ability to control, to a certain ex- tent, properties of coordination polymer or discrete oligonu- clear complex, which depend on the properties of the build- ing block (for example, magnetic properties [28, 30, 32]). Notably, though many coordination polymers contain *Address correspondence to this author at the Department of Chemistry, Taras Shevchenko National University of Kyiv, Volodymyrska str. 62, Kiev 01601, Ukraine; Tel: +380-44-239-33-93; Fax: +380-44-239-33-93; E-mail: ifritsky@yahoo.com polynuclear units [33], in the majority of cases such units are formed in the reaction mixture due to self-assembling from mononuclear species [34, 35] or, in some cases, destruction of a parent complex possessing higher nuclearity [32]. The topology of coordination polymer, assembled from polynuclear units, can be pre-determined only in the case if all potential vacancies in coordination spheres of the metal ions are filled by donor atoms of the ligands, and, in turn, all donor atoms of the ligands participate in metal ions bonding. This strategy was utilized for assembling of coordination polymers on the basis of carboxylates [27-31], however to- pology control using oximate building blocks was not achieved, as shown in this review. A logical conclusion from this concept is that topology control can not be achieved in the case of supramolecular systems, because bonding direc- tion can not be guessed (the bonding direction in this case is governed by H-bonding, but the energy of H-bonding is comparable with crystal lattice energy, and participation of solvent or other guest molecules in H-bonding can not be avoided). Hydroxamic acids can be considered as analogs of oxi- mes (Fig. 1) and for this reason it seems reasonable to con- sider hydroxamate complexes together with oximates in this review. Among hydroxamates, special attention will be paid to metallacrowns – polynuclear complexes possessing a cy- clic structure formed by a repeating –[M-N-O]- moiety [36, 37]. Cyclic structure, containing O donor atoms directed "inside", allows considering these compounds as inorganic structural analogues of crown ethers (Fig. 1) [38-40]. It should be noted, that many metallacrown complexes are formed by the anions of hydroxamic acids, derived from natural chiral -aminoacids, and therefore these systems are