Coordination modes of 3-hydroxypicolinic acid: Synthesis and structural characterization of polymeric mercury(II) complexes (original) (raw)
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Polyhedron, 2009
Several mercury(II) complexes of 2-quinaldic acid (quinH; IUPAC name: quinoline-2-carboxylic acid) were synthesized and characterized. [Hg(quin) 2 (OH 2 )] (1) was obtained as the reaction product of mercury(II) chloride and 2-quinaldic acid in an aqueous media, while a mixture of 1, [(quinH 2 )(HgCl 3 )]Á 2quinHÁH 2 O (2), and [Hg(quin) 2 (EtOH)]ÁH 2 O (3) was obtained from a 96% ethanol solution. Pure [HgCl(quin)(quinH)] (4) was obtained as the first reaction product when the reaction was performed in absolute alcohol. After isolation of 4 from the filtrate the mixture of 1-3 was again obtained. The Xray single-crystal structure analysis reveals that the ligand, 2-quinaldic acid is coordinated to the Hg 2+ ion as a N,O-chelating quinaldate ion in structures 1, 3 and 4. In the structure of 2 polymeric ½HgCl 3 n nÀ anions are formed with a very deformed trigonal-bipyramidal 3 + 2 mercury coordination sphere while the ligand, 2-quinaldic acid exists in the zwitterionic form as quinH, and as a cation, quinH 2 þ . The coordination polyhedron in 1 and 4 can be described as 2 + 3 and 4 + 1 deformed trigonal-bipyramidal and square-pyramidal geometry with the water molecule and chlorine atom at the fifth site in 1 and 4, respectively. The coordination sphere in 3 is square-pyramidal with the ethanol molecule at the vertex, however through additional HgÁÁÁO contacts centrosymmetric dimers are formed resulting in a 5 + 1 effective octahedral mercury coordination.
Six new 1-benzoyl-3-phenylthiourea and 1-benzoyl-3-(2-methylphenyl)thiourea complexes of mercury(II) were obtained in the reactions of the ligands with HgX 2 in methanol (X = Cl, Br, I). Their structures, determined by single-crystal X-ray diffraction analysis, exhibit different stoichiometries and molecular organization. Coordination centers adopt more or less distorted tetrahedral geometry (five structures) or distorted trigonal bipyramidal geometry (one structure). In four cases 1D coordination polymers were formed and in the other two molecular compounds were found. In three cases solvent molecules (H 2 O or MeOH) were found in crystal structure. Although all compounds share common intramolecular N-HÁ Á ÁO@C structural motif they exhibit unique hydrogen bonding pattern. Common pc11 rod group symmetry of polymer chains (where applicable) allows simplified classification of the 3D packing as parallel stacking of trapezoidal prisms.
Reaction of [Hg(OAc)2] with two mole proportion of LH(LH= benz-1,3-imidazoline-2-thione, benz-1,3-oxazoline-2-thione or benz-1,3-thiazoline-2-thione ) in the presence Et3N gave linear complexes of the type [HgL2]. Treatment of [HgL2] with two mole proportion of PPh3 or one mole proportion of the diphosphine Ph2P(CH2)nPPh2 gave tetrahedral complexes of the type [HgL2(PPh3)2], [HgL2(m-diphos)]2 (n=1) or [HgL2(diphos)] (n = 2 or 3) respectively, While treatment with two mole proportion of Ph2PCH2PPh2 (dppm) gave octahedral complexes of the type[HgL2(dppm)2]. The preparated complexes have been characterized by mean of elemental analysis, molar conductance, i.r. spectral data, 1H, 13C-{1H}, 31P-{1H} n.m.r. data. Single crystal x-ray analysis of two of the complexes ( 11 and 13 ) has reveled the presence of a tetrahedral coordination geometry about mercury.
Journal of Coordination Chemistry, 2018
Reaction of a-keto stabilized sulfur ylide (Me) 2 SCHC(O)C 6 H 4-p-CN (Y) with HgX 2 (X ¼ Cl, Br, and I) led to the formation of new dinuclear products of the type [HgX 2 (Y)] 2 (X ¼ Cl (1), Br (2), and I (3)). Furthermore, the reaction of the corresponding sulfur ylide (Y) with Hg(NO 3) 2 ÁH 2 O in equimolar ratio, using methanol as a solvent, was shown to produce the polynuclear complex [(Y)Hg(NO 3) 2 ] n (4). The obtained compounds were characterized using elemental analysis, IR, 1 H and 13 C NMR techniques. The structures of compounds Y and 1 were characterized by single-crystal X-ray diffraction (XRD) analysis. Also, in order to confirm the crystalline nature of complexes 1-3, powder XRD pattern was used. Likewise, the antioxidant property of the complexes was examined by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging which revealed the strong-to-moderate radical scavenging ability (IC 50 ; 0.163 ± 0.004 to 0.936 ± 0.012 mgÁmL À1) of the synthesized compounds. Further, results from this study indicated that the compounds possess moderate antibacterial activity.
Journal of the Chilean Chemical Society
The new complex of [Hg(2-AMPy) 2 Br] 2 .HgBr 4 (1) was synthesized from the reaction of HgBr 2 with 2-(aminomethyl)pyridine (2-AMPy) in methanolic solution. Suitable crystals of 1 for diffraction experiment was obtained by slow evaporation from DMSO. Resulted complex was characterized by IR, elemental analysis, thermal analysis and single crystal X-ray diffraction. In this compound, two five-coordinated mercury centers in the cationic parts have slightly and highly distorted square-based pyramidal geometries by the trigonal-indexes, τ 5 , of 0.18 and 0.49, respectively. According to four-coordinate geometry index, τ4, of 0.95, anionic part has perfect tetrahedral geometry.
1999
The novel complex of biologically active 3,3-dimethylglutarimide, aqua-bis(3,3-dimethylglutarimidato)mercury(II) has been obtained and its structure determined by single crystal X-ray diffraction and vibrational spectroscopic studies. The crystals of C 14 H 20 N 2 O 4 Hg·H 2 O are monoclinic, space group P2 1 /c, a 6.085 , b 19.686(4), c 14.433(3) Å , b 93.32(3)Њ and Z 4. The structure was solved by heavy atom method and refined to R 0.035, R w 0.093 for 2075 unique reflections. The mercury atom is almost linearly bonded to two deprotonated nitrogen atoms of the glutarimidate rings [Hg-N 2.035(8) and 2.028(8) Å , N-Hg-N H 169.2(3)Њ] and is also coordinated to one water molecule in the axial position [Hg-O 2.643(8) Å , N-Hg-O 98.5(3)Њ]. The water molecule forms strong hydrogen bonds to the carbonyl groups of the neighbouring molecules in the unit cell.
Main Group Metal Chemistry, 2009
A series of new and novel complexes of the types [(Cl)Hg(L)] and [Hg(L) 2 ] [where L= Schiff bases; salicylidene-2-methyl-l-aminobenzene (smabH) and vanilidene-1-aminobenzene (vabH)] of mercury(II) have been synthesized by the interactions of mercury(II) chloride with sodium salts of Schiff bases in the presence of THF-MeOH mixture, in 1:1 and 1:2 molar ratio(s) respectively, to produce complexes; [(μ-Cl) 2 Hg 2 (smab) 2 ] (1), [Hg(smab) 2 ] (2), [(μ-01) 2 Η 82 (ν 3^2 ] (3) and [Hg(vab) 2 ] (4). Further, complex [(μ-Cl) 2 Hg 2 (smab) 2 ] (1) has been treated with various aryloxo-, alkoxo-, tetraisopropoxyaluminate, benzoxazolato-and benzimidazolato-salts of sodium in equimolar ratio, to produce new mixed ligand complexes such as, [^-OAr) 2 Hg 2 (smab) 2 ](5), [^-OPr^Hg^smab^] (6), [{(μ-ΟΡ0 2 Α1(ΟΡι0 2 }Ι^(8ΐτκώ)] (7), [{n 2-(pbox)}Hg(smab)] (8) and [{n. 2-(pbz)}Hg(smab)] (9). These complexes have been characterized by elemental analysis (Hg, Cl, C, Η & Ν), melting points and spectral (UV-vis, FT-IR, Ή-, I3 C-NMR and FAB-MS) data, whereas the structure of the complexes have been tentatively determined by FAB-MS spectral studies. A thermogravimetric analysis (for complex 4) and X-ray powder diffraction studies (for complex 3) are also reported herein.
Journal of Molecular Structure, 2015
Three novel Hg(II) complexes 1-3 of asymmetrical hydrazone-pyridine based ligands, L 1-L 3 , with distinct coordination structures have been prepared and characterized by a single crystal X-ray diffraction, elemental and thermal analysis, and IR spectroscopy. The complexes form either discrete units with one (1) or two (2) organic ligands, or one-dimensional polymers (3). Hence the ligands can be regarded as chelating (1), mono-dentate (2) or bridging (3) agents. The mercury center is essentially neutralized in each complex by two iodide anions. The coordination in complexes 2 and 3 adopts deformed tetrahedral shapes. In contrast the Hg(II) cation in complex 1 binds three coplanar ligating atoms (O,N,N) and, as with pincer ligands, its coordination polyhedron is supplemented with two Ianions in apical positions. The structural diversity in these complexes is strongly influenced by the position of N atom in pyridine derived moieties. The crystal structure is stabilized by N/O-H…N/O/I hydrogen bonds and π…π interactions.