24 ( 2018 ) No . 1 37 NEW MX 2 AND M ’ Cl 3 ( M = Cu , Zn ; M ’ = Y , Dy , Pr ; X = Cl , Br ) MALEATO COMPLEXES AND TETRAPHENYLANTIMONY FORMIATE ADDUCT : SYNTHESIS AND INFRARED STUDY

Eleven complexes and adduct have been synthesized and studied by infrared. The suggested structures are discrete with tetrahedral, trigonal bipyramidal, square planar or octahedral environments around Zn, Ni, Hg and Cu centres – the coordination number is eight in the yttrium compound and ten in the dysprosium one-. The maleate anion behaves as a bidentate, a monochelating, a bichelating or a tetradentate ligand while the formiate anion behaves as a monodentate ligand. For compounds containing a protonated amine or a methanol molecule, when hydrogen bonds are considered a supramolecular architecture may be obtained.


EXPERIMENTAL SETUP
(CyNH3)2O2C(CH)2CO2 (L1) and (iPr2NH2)2O2C(CH)2CO2 (L2) have been obtained as white powders on allowing monocyclohexylamine (CyNH2) and diisopropylamine (iPr2NH) to react in water with maleic acid in 1:1 ratio respectively.Compounds A, B, D, F, G and J were obtained as white powders after a slow solvent evaporation at room temperature, on allowing L1 to react in methanol with, CuCl2.2H2O in a 1:2 ratio (A) or in a 1:2 ratio (F), ZnCl2 in a 1:2 ratio (B), CuBr2 in a 1:2 ratio (D), HgCl2 in a 1:2 ratio (G) and DyCl3 in a 1:1 ratio (J).Compounds C, E, H, I and K were obtained on allowing L2 to react in methanol with NiCl2 in a 1:2 ratio (C), ZnCl2 in a 1:2 ratio (E), HgCl2 in a 1:2 ratio (H), YCl3 in a 1:1 ratio (I), and SbPh3 in a 1:1 ratio (K).All the solutions were stirred around two hours before being submitted to a slow solvent evaporation.
The analytical data [% calculated (% found)], have allowed to suggest the following formulae (Table 1).

Compounds obtained with MCl2 moiety
Let us consider the main IR data in cm -1 of the studied compounds (Table 2).From these infrared data we have suggested: -For A, B, C, D and E, while considering the complex-anion, a dimeric structure with two external maleato anions behaving as monochelating ligands and two bridging halogen atoms, the environment around the metallic centre being square planar in the cases of Cu and Ni (Figure 1a) or tetrahedral in the case of Zn (Figure 1b).-For F, a dimer similar to the one suggested in the previous zinc compound by replacing the bridging chlorides by bridging water molecules (Figure 2).-For G and H, while considering the complex-anion [Hg(O2C(CH)2CO2)2] 2-, a discrete structure in which the maleato dianion behaves as a monochelating ligand, the environment around the mercury centre being tetrahedral (Figure 3).-For I, by dimerizing, a discrete structure containing four metallic centres distributed in a tetrahedron manner, the metallic centres being linked by bidentate maleato anions leading to a P4O6 structure type.Each yttrium centre is then coordinated by a methanol molecule giving finally a P4O10 structure type, the remaining methanol molecules being lattice (Figure 4).-For J, while considering the complex-anion, after a dimerization followed by a rearrangement, two structures:  A first discrete one in which the four metal centres distributed in a square manner are connected to each other via bidentate maleato anions, each dysprosium centre being then bonded to two chlorine atoms (Figure 5a).The coordination number of each metal centre is seven (7), very common in rare earths chemistry. A second two components one, the first component being a dysprosium centre monochelated by the five maleates, the second component consisting of three [DyCl2] + moieties linked by pair through a bridging chlorine atom, and two chloride ions both coordinating the three dysprosium centres (Figure 5b).-For K, a first discrete structure with a monodente formiate coordinating the SbPh4 residue, the environment around the Sb centre being pentagonal (Figure 6a) and a second dimer one, the dimerization being ensured by O-H…O hydrogen bonds (Figure 6b).
In all the structures except for F and K, the cations interact with complex-anions via hydrogen bonds.While considering intermolecular hydrogen bonds supramolecular architectures may be obtained in all the suggested structures.

CONCLUSION
The studied complexes and adduct have discrete structures, the maleate behaving as a monochelating, a bichelating, a bidentate or a tetradentate ligand whereas the formiate behaves as a monodentate ligand.The environment around the transitional metal centres is tetrahedral or square planar.The rare earth yttrium centre is four coordinated while the dysprosium centre is five, seven and ten coordinated.In all the proposed structures, while considering extra hydrogen bonding interactions, supramolecular architectures may be obtained.

Fig. 1a .
Fig. 1a.Proposed structure for compounds A, C and D.

Fig. 3 .
Fig. 3. Proposed structure for compounds G and H.

Table 1 .
Results of the elemental analyses of compounds A

-H. Compound Chemical formula Elemental analysis [%]
Infrared spectra were recorded on a Bruker Vector 22 spectrometer equipped with a Specac Golden Gate TM ATR device.Infrared data are given in cm -1 [IR abbreviations: (vs) very strong, (s) strong, (m) medium].Elemental analyses were performed at the "Institut de Chimie Moléculaire", University of Bourgundy, Dijon-France.All chemicals were purchased from Sigma-Aldrich Chemie GmbH, Steinheim, Germany and used without any further purification.

Table 2 .
Main IR data of compounds A-K.