New nickel(II) carboxylate-phosphonate cluster: Synthesis and structure

Abstract

Among many polynuclear phosphonate complexes of transition metals, the so called mixed ligand com plexes play a special role. The use of additional ligands in the synthesis of polynuclear architecture makes it possible to solve the problem of a low solubility of the phosphonate complexes and, finally, to obtain the polynuclear architecture with a specified set of physi cochemical properties. This class of compounds attracts attention of researchers due to their ability to ion exchange, adsorption, and proton conductivity. This assumes their potential use in photochemistry, electrooptics, and catalysis. In addition, the possibility of using such molecules in sensor devices and as molecular precursors for the preparation of various materials cannot be excluded [1][2][3][4][5][6][7][8][9].The method of self assembling can be distin guished among the methods for the preparation of such homo and heteronuclear molecules. In this method, the heteroligand coordination sphere is formed by phosphonate bridges and, for example, car boxylate anions [10][11][12][13][14][15][16][17][18][19] or other organic ligands of the type of 2 hydroxypyridine derivatives [20][21][22][23].In this work, we used trimethylacetate ligands determining, as a rule, the high spin state of metal atoms in transition metal complexes and containing bulky tert butyl substituents that provide the forma tion of the insular structure with high solubility in organic media. It could be assumed that the use of metal containing fragments with the high spin metal ions in molecular self assembling of a polynuclear structure with phosphonate bridges would result in the formation of a magnetically active architecture, because the presence of unpaired electrons on each metal center induces, as a rule, spin-spin exchange interactions between the adjacent metal ions and the appearance of antiferro , ferri , or ferromagnetic properties [10, 15, 17-19, 24, 25].As shown in earlier works on the synthesis of the phosphonate complexes, the additional use of Hmhp considerably extends possibilities of the synthesis of compounds with higher nuclearity [26,27]. However, the data on the influence of the nature of metal centers and additional ligands and their geometric parameters and synthesis conditions on the geometry of the poly nuclear metal phosphonates are rather restricted and, therefore, they require more detailed investigation.The results on chemical assembling of the polynu clear mixed ligand Ni(II) complexes are presented in this work. EXPERIMENTALComplex I was synthesized in air using commer cially available solvents MeCN and THF. Phenylphos phonic acid (Aldrich), pivalic acid (Aldrich), Hmhp (Fluka), and KOH (analytical grade) were used for the synthesis. Phenylphosphonic acid potassium salt K 2 O 3 PPh was obtained by the reaction of KOH and Н 2 O 3 PPh. Nickel pivalate [Ni 9 (OH) 6 (Piv) 12 (HPiv) 4 ] (II) was synthesized according to a described proce dure [28].Synthesis of [(μ 2 Hmhp) 6 Ni 12 (µ 3 OH) 4 (µ 6 O 3 PPh) 4 (μ 2 Piv) 12 ] · 7.5MeCN ⋅ 1.5THF (I ⋅ 7....

Structural Diversity of Nickel and Manganese Chloride Complexes with Pyridin-2-One

“…Hmhp molecules ligated in the 2.2 fashion contribute to the design of hexanuclear nickel cages in some nickel benzoato and pivalato complexes [57,58]. The same ligation of Hmhp was found in a dodecanuclear nickel-phosphonate cluster [59].…”

“…Molecules 2020, 25, x FOR PEER REVIEW 14 of 23 A µ2-oxygen ligation of Hhp is well documented in the dinuclear copper(II) halides or acetate [36,54] and silver(I) complexes [55,56]. In nickel compounds, only Hhp derivatives-Hchp or Hmhpwere observed as neutral organic O-donor bridging ligands, which in cooperation with other bridging anions connects metal ions in hexa- [57,58], nona- [27] and dodecanuclear [20,59] clusters. Copper ions in dinuclear compounds are linked by two Hhp molecules [36,54], while three molecules are involved in a bridging coordination to a pair of 3d metal ions only in a vanadium complex of Hmhp [79].…”

Linked Nickel Metallacrowns from a Phosphonate/2-Pyridyloximate Blend of Ligands: Structure and Magnetic Properties

“…In complex 2, the inverse (μ 3 -OH)[9-MC Ni II -3] links one Cs + cation in a direct fashion. The OH − ligands are placed 0.492 and 0.570 Å out of the main Ni (1,2,3) or Ni (4,5,6) planes, respectively, whereas in the opposite sense, the O oximate donors link the Cs + ion. The As could be expected, the {Ni−O−N−} 3 rings in complexes 3 and 4 are flattened in comparison with the inverse metallacrown in 2 (Figure 6).…”

“…Recently, other authors have characterized new molecular nickel systems from RPO 3 2− /pivalate (Ni 8 and Ni 10 ) 6 and RPO 3 2− /calixarene (Ni 8 , Ni 12 ,and Ni 16 ) mixtures of ligands. 7 Another successful strategy has been the employment of functionalized 8 phosphonates or its combination with polyoxometallates.…”