Phosphonate Cages Research Articles

Magnetic and thermodynamic properties of the octanuclear nickel phosphonate-based cage

We report a detailed theoretical investigation into the influence of anisotropy on the magnetic and thermodynamic properties of an octanuclear nickel phosphonate cage with butterfly-shaped molecular geometry, namely Ni8(μ3−OH)4(OMe)2(O3PR1)2(O2CtBu)6(HO2CtBu)8. To validate our exact diagonalization approach, we firstly compare results with simulations and experiment in the isotropic case. Having established concurrence, we then introduce uniaxial single-ion anisotropy and Heisenberg exchange anisotropy between interacted nickel atoms. We then examine effects of both anisotropy parameters on the magnetization process, as well as on the specific heat of the model. We predict intermediate magnetization plateaus, including zero plateau, and magnetization jumps with magnetic ground-state phase transitions at low temperature T=1 K. The magnetization plateaus are strongly dependent on both the levels of exchange anisotropy and single-ion anisotropy. Varying the former leads to change in width and magnetic position of all intermediate plateaus while they become wider upon increasing the latter. The specific heat of the model manifests a Schottky-type maximum at moderate temperature in the presence of weak magnetic fields, when the system is isotropic. The introduction of anisotropy results in substantial variations in the thermal behavior of the specific heat. Indeed, by tuning anisotropy parameters the Schottky peak convert to a double-peak temperature dependence that coincided with the magnetization jumps. We call for these theoretical predictions to be verified experimentally at low temperature.

Multinuclear Palladium Olefin Polymerization Catalysts Based on Self-Assembled Zinc Phosphonate Cages

The phosphine–phosphonate–sulfonate proligand HP+(4-tBu-Ph)(2-PO3H2-5-Me-Ph)(2-SO3–-5-Me-Ph) (H3[OP-P-SO], 1-H3) was investigated as a building block for the self-assembly of multinuclear Pd compounds based on zinc phosphonate scaffolds. 1-H3 reacts with Zn(OAc)2·2H2O to afford {Zn[1-H]}4, which adopts a Zn4P4O8 ring structure in which the Zn centers are linked by μ2-κ1,κ1-bridging (aryl)PO3H– ligands. {Zn[1-H]}4 reacts with (TMEDA)PdMe2 and pyridine to generate {[(κ2-OP-P-SO)PdMe(py)][Zn(TMEDA)]}2 (2), in which two [(κ2-OP-P-SO)PdMe(py)]2– units are linked through a Zn2P2O4 ring. The sequential reaction of CH3OH-free {Zn[1-H]}4 with (COD)PdMe2 and 4-tBu-py generates {[κ2-(Zn-OP-P-SO)]PdMe(4-tBu-py)}4 (4-(4-tBu-py)), in which four [(κ2-OP-P-SO)PdMe(4-tBu-py)]2– units are arranged on the periphery of a double-four-ring (D4R) Zn4P4O12 cage. Analogous 4-L species were generated by the reaction of {Zn[1-H]}4, (COD)PdMe2, and other pyridine ligands. 4-py reacts with CH3OH to form a trimeric cluster 3-py, which...

High Nuclearity (Octa-, Dodeca-, and Pentadecanuclear) Metal (M = CoII, NiII) Phosphonate Cages: Synthesis, Structure, and Magnetic Behavior

The synthesis, structural characterization, and magnetic property studies of five new transition metal (M = Co, Ni) phosphonate-based cages are reported. Three substituted phenyl and benzyl phosphonate ligands [RPO3H2; R1 = p-tert-butylbenzyl, R2 = p-tert-butylphenyl, R3 = 3-chlorobenzyl] were synthesized and employed to seek out high-nuclearity cages. Complexes 1-3 are quasi-isostructural and feature a dodecanuclear metal-oxo core having the general molecular formula of [M12(μ3-OH)4 (O3PR)4(O2C(t)Bu)6 (HO2C(t)Bu)6(HCO3)6] {M = Co, Ni and R = R1 for 1 (Co12), R2 for 2, 3 (Co12, Ni12)}. The twelve metal centers are arranged at the vertices of a truncated tetrahedron in a manner similar to Keggin ion. Complex 4 is an octanuclear nickel phosphonate cage [Ni8(μ3-OH)4 (OMe)2(O3PR1)2 (O2C(t)Bu)6(HO2C(t)Bu)8], and complex 5 represents a pentadecanuclear cobalt phosphonate cage, [Co15(chp)8(chpH) (O3PR3)8(O2C(t)Bu)6], where chpH = 6-chloro-2-hydroxypyridine. Structural investigation reveals some interesting geometrical features in the molecular cores, which may provide new models in single molecular magnetic materials. Magnetic property measurements of compounds 1-5 indicate the coexistence of both antiferromagnetic and ferromagnetic interactions between magnetic centers for all cages.

Correction to Serendipitous Assemblies of Two Large Phosphonate Cages: A Co15 Distorted Molecular Cube and a Co12 Butterfly Type Core Structure

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionCorrection to Serendipitous Assemblies of Two Large Phosphonate Cages: A Co15 Distorted Molecular Cube and a Co12 Butterfly Type Core StructureJaveed Ahmad Sheikh, Soumyabrata Goswami, Amit Adhikary, and Sanjit Konar*Cite this: Inorg. Chem. 2013, 52, 11, 6765Publication Date (Web):May 14, 2013Publication History Published online14 May 2013Published inissue 3 June 2013https://doi.org/10.1021/ic401077vCopyright © 2013 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views442Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (111 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Molecular amino-phosphonate cobalt–lanthanide clusters

The use of 1-amino-1-cyclohexyl phosphonic acid, a functionalised phosphonate, leads to the synthesis of two new structural types for 3d-4f phosphonate cages with unusual structural cores and which show high magnetocaloric effects.

Multicomponent Assembly of Anionic and Neutral Decanuclear Copper(II) Phosphonate Cages

A multicomponent synthetic strategy involving copper(II) ions, tert-butylphosphonic acid (t-BuPO(3)H(2)) and 3-substituted pyrazole ligands has been adopted for the synthesis of soluble molecular copper(II) phosphonates. The use of six different 3-substituted pyrazoles, 3-R-PzH [R = H, Me, CF(3), Ph, 2-pyridyl (2-Py), and 2-methoxyphenyl (2-MeO-C(6)H(4))] as ancillary ligands afforded nine different decanuclear cages, [Cu(5)(μ(3)-OH)(2)(O(3)P-t-Bu)(3)(3-R-Pz)(2)(X)(2)](2)·(Y) where R = H, X = t-BuPO(3)H, and Y = (Et(3)NH(+))(4)(solvent) (1); R = Me, X = 3-MePzH, and Y = solvent (2); R = Me, X = t-BuPO(3)H, and Y = (Et(3)NH(+))(4)(solvent) (3); R = CF(3), X = t-BuPO(3)H, and Y = (Et(3)NH(+))(4)(solvent) (4); R = Ph, X = 3-PhPzH, and Y = solvent (5); R = 2-Py, X = 0.5 MeOH, and Y = solvent (6); R = 2-Py, X = none, and Y = solvent (7); R = 2-Py, X = H(2)O, and Y = (Et(3)NH(+)·PF(6)(-))(2)(solvent) (8); R = 2-MeO-C(6)H(4), X = MeOH or 0.5:0.5 MeOH/H(2)O, and Y = solvent (9). Compounds 1-6, 8, and 9 were isolated using a direct synthetic method which involves the reaction of copper(II) salts and the ligands, while 7 was obtained from an indirect route involving the reaction of preformed copper-pyridylpyrazolate precursor complexes and t-BuPO(3)H(2). The decametallic compounds 1-9 possess a butterfly shaped core. The core of the cages 1, 3, and 4 are tetraanionic and contain more phosphonates than pyrazole ligands, while the other cages are neutral and contain more pyrazoles than phosphonate ligands. Compounds 1-6 have been studied by electrospray ionization-high-resolution mass spectrometry (ESI-HRMS). The decanuclear cage 6 was shown to be a good plasmid modifier.

Solvothermal preparation of iron phosphonate cages

Three new iron(III) phosphonate cage-like complexes with [Fe4], [Fe9] and [Fe14] cores have been synthesized by solvothermal reaction with various starting materials. Magnetic studies show overall antiferromagnetic interaction presented in these cages.

MnII–GdIII Phosphonate Cages with a Large Magnetocaloric Effect

) is the ideal spin center for MCEas it has a high isotropic spin; however, the internal natureof the 4f electrons hampers the magnetic communicationbetween them. A mixed-metal 3d–4f approach should havethe advantage of a better magnetic interaction and thus,a larger ground spin in the preferred ferromagnetic case. Wehave used this approach to make cobalt(II) (s=3/2) andnickel(II) (s=1) gadolinium phosphonate complexes withlarge MCEs.

Synthesis and structures of a pentanuclear Al(iii) phosphonate cage, an In(iii) phosphonate polymer, and coordination compounds of the corresponding phosphonate ester with GaI3 and InCl3

A cationic, pentanuclear aluminium phosphonate cage, [L(4)Al(5)Cl(6)(THF)(6)]Cl, 1, supported by (phthalimidomethyl) phosphonate, (L), has been synthesized and characterized. This polynuclear cage features the phosphonate ligand in an unusual coordination mode, supporting five aluminium atoms in two different environments. In comparison, the aqueous reaction of LH(2) with In(ClO(4))(3) afforded [{(LH)In(H(2)O)}(H(2)O)(2)(ClO(4))](n), 2, an indium(III) phosphonate coordination polymer, that has been crystallographically characterized. Reactions of the corresponding phosphonate ester, diethyl (phthalimidomethyl) phosphonate, (L'), with GaI(3) and InCl(3) afforded the simple coordination complexes, [L'·GaI(3)], 3, and [L'·InCl(3)(THF)], 4.

Synthesis and characterisation of cobalt(ii) phosphonate cage complexes utilizing carboxylates and pyridonates as co-ligands

The synthesis and structures of fifteen new cobalt complexes containing phosphonate ligands are reported. The compounds also utilize carboxylates and 6-chloro-2-pyridonate (chp) as co-ligands. The majority of the compounds are decametallic: [Co(10)(chp)(12)(O(3)PPh)(2)(O(2)CPh)(4)(H(2)O)(4)], [Co(10)(chp)(12)(O(3)PPh)(2)(O(2)C(t)Bu)(4)(H(2)O)(4)], [Co(10)(chp)(12)(O(3)PPh)(2)(O(2)CPh(t)Bu)(4)(H(2)O)(4)], [Co(10)(chp)(6)(O(3)PCH(2)Ph)(2)(O(2)CPh)(8)(F)(2) (H(2)O)(2)(EtOAc)(2)], [Co(10)(chp)(8)(O(3)PCH(2)Ph)(2)(O(2)CPh)(8)(F)(2)(MeCN)(2)](HNEt(3))(2), [Co(10)(chp)(6)(O(3)PCH(2)Ph)(2)(O(2)C(t)Bu)(8)(F)(2)(H(2)O)(2)(MeCOMe)(2)], [Co(10)(chp)(6)(O(3)PMe)(2) (O(2)C(t)Bu)(8)(F)(2)(MeCN)(4)], [Co(10)(chp)(6)(O(3)PEt)(2)(O(2)CPh)(8)(F)(2)(MeCN)(4)], [Co(10)(chp)(6)(O(3)POct)(2)(O(2)CPh)(8)(F)(2)(MeCN)(4)], [Co(10)(chp)(8)(Hchp)(2)(O(3)PCH(2)Nap) (O(2)CPh)(7)(OH)(3)(H(2)O)], [Co(10)(chp)(12)(O(3)PPh)(2)(O(2)CPh-2-Ph)(4)(H(2)O)(4)] and [Co(10)(chp)(12)(O(3)PMe)(2)(O(2)CPh-2-Ph)(4)(H(2)O)(4)]. Two nine-metal cages and one hexametallic cage are also reported: [Co(9)(chp)(9)(O(3)P(t)Bu)(O(2)C(t)Bu)(6)(OH)], [Co(9)(chp)(7)(O(3)PCH(2)Ph)(2)(O(3)PCH(2)Ph)(O(2)CCPh(3))(5)(OH)(H(2)O)(2)(MeCN)] and [Co(6)(chp)(6)(Hchp)(2)(O(3)P(t)Bu)(O(2)CPh-2-Ph)(3)(F)(H(2)O)](HNEt(3))(Cl). Magnetic studies show predominantly anti-ferromagnetic exchange interactions between the cobalt(ii) sites, with diamagnetic ground states for most of the compounds studied.

Octa- and hexametallic iron(iii)–potassium phosphonate cages

Two new iron(III)-potassium phosphonate cage complexes with {K(2)Fe(6)} and {K(2)Fe(4)} cores are reported. Magnetic studies reveal antiferromagnetic interactions between the Fe(III) centres occur in these cages.

Monoorganooxotin cage, diorganotin ladders, diorganotin double chain and triorganotin single chain formed with phosphonate and arsonate ligands

The solvothermal reaction of n-BuSn(O)OH with PhPO(3)H(2) afforded the hexanuclear monoorganooxotin phosphonate cage, {[(n-BuSn)(3)(MeO)(3)O](2)(O(3)PPh)(4)}.MeOH 1. When the n-Bu(2)Sn(PhCO(2))(2) precursor reacted with PhPO(3)H(2) in a 1 : 1 stoichiometric ratio, the diorganotin phosphonate ladder [n-Bu(2)SnO(3)PPh](n) 2 was obtained. The reaction of [n-Bu(2)(PrO)Sn](2)O with 4-OH-3-NO(2)-C(6)H(3)AsO(3)H(2) affords the diorganotin arsonate ladder [n-Bu(2)Sn(4-OH-3-NO(2)-C(6)H(3)AsO(3))](n) 3, while the reaction of [n-Bu(2)(PrO)Sn](2)O with 4-NO(2)-C(6)H(4)AsO(3)H(2) and 4-Me-C(6)H(4)SO(3)H gives an diorganotin double chain [n-Bu(2)Sn(4-Me-C(6)H(4)SO(3))(4-NO(2)-C(6)H(4)AsO(3)H)](n) 4, which contains both sulfonate and arsonate ligands. The reaction of 4-NO(2)-C(6)H(4)AsO(3)H(2), EtONa, and Ph(3)SnCl yields a new triorganotin arsonate single chain [(Ph(3)Sn)(4)(4-NO(2)-C(6)H(4)AsO(3))(2).H(2)O](n) 5. The NMR ((1)H, (13)C, (119)Sn) spectra of compounds 1 and 4 were studied.

Synthesis, structural characterisation and magnetic studies of polymetallic iron phosphonate cages

Four new polymetallic iron(III) phosphonate cages have been made and structurally characterised. These are an octanuclear cage [Fe(8)O(3)(OH)(2)(O(2)C(t)Bu)(11)(PhCH(2)PO(3))(3)(py)(3)], a decanuclear cage [Fe(10)O(2)(OH)(8)(O(2)C(t)Bu)(10)(PhCH(2)PO(3))(4)(pip)(2)], a heterometallic cage [Fe(6)Li(5)(mu(3)-O)(2)((t)BuPO(3))(6)(O(2)C(t)Bu)(8)(MeOH)(2)(Py)(4)] and a tridecanuclear cage [Et(3)NH](2)[Fe(13)(mu(3)-O)(3)(mu(2)-OH)(7)((t)BuPO(3))(7)(Me(3)CCO(2))(14)(H(2)O)] (pip = piperidine, py = pyridine). Magnetic studies of the first three compounds show anti-ferromagnetic exchange between the iron(III) centers leading to diamagnetic ground states for the homometallic cages. For the heterometallic cage, the six Fe(III) centers are arranged in two triangles, and each triangle has an S = 1/2 spin ground state.

Synthesis and structural and magnetic characterisation of cobalt(ii)–sodium phosphonate cage compounds

The reaction of cobalt salts with phosphonic acids in the presence of 6-chloro-2-hydroxypyridine as a co-ligand, using sodium methoxide as a base, leads to a series of new polymetallic cobalt cages. Variation of the phosphonate present and the cobalt salt leads to {Co(6)Na(8)}, {Co(12)}, {Co(13)Na(6)}, {Co(14)Na(4)} and {Co(15)Na} cages, all of which have been characterized by X-ray crystallography. Using lithium methoxide produces a sixth cage with a {Co(6)Li(9)} core. The structures are, in general, extremely irregular with no structural motifs common to the six cages. Magnetic studies of these cages show a general decline in the product chi(m)T with T, but for {Co(13)Na(6)}, {Co(15)Na} and {Co(12)} there are maxima at low temperature, which suggest non-diamagnetic ground states. Investigation of the dynamic behaviour of the magnetisation of these complexes shows that the {Co(13)Na(6)}, and possibly the {Co(12)} cage, appear to display slow relaxation of magnetisation.

New Directions in the Preparation and Redox Chemistry of Fluoride-Templated Tetranuclear Vanadium Phosphonate Cage Compounds, Mn+[(V2O3)2(RPO3)4⊂F]n

A new and simple preparation method for fluoride-templated tetranuclear vanadium phosphonate cage compounds, M(n+)[(V2O3)2(RPO3)4<F]n is outlined. The crystalline products were characterized by X-ray diffraction, elemental analysis, and thermogravimetric analysis. Using the acceptable solubility of the products, multinuclear NMR could be performed on the corresponding solutions. Some insight into the process of formation of the cage compounds in solution could be reached by monitoring the corresponding reaction mixture by multinuclear NMR. The template function of the F(-) ion could be demonstrated together with the fact that the non-transition-metal ions (M(n+)) used here (phosphonium ions) have no direct effect on the formation of the cage. In contrast, the redox behavior of these compounds in the solid state distinctly depends on the cations. This could be easily investigated by electron paramagnetic resonance because the mixed-valence species (3V(V)/V(IV)) can be produced chemically or thermally induced in solution as well as in the solid state. In the latter case, the reaction of the cage with H2 activated on the platinum powder can be regarded as a key experiment for understanding the redox process of the title compounds in the solid state. The role of specific interactions in solution at the tumbling rate and the localization of spin density in the cage could be demonstrated by the reduction performed with 1-methylimidazole and quinoline. While the substituents R = Me and Ph have only a small influence on the cage formation in solution, they have a significant influence on the redox reaction and structural relaxation in the solid state.

Mixed-Valent Dodecanuclear Vanadium Cluster Encapsulating Chloride Anions and Its Reaction To Form a “Bowl”-Shaped Cluster

Two oxovanadium phosphonate cage compounds have been synthesized in an organic solvent, and their characterization has been done by single-crystal X-ray analysis, IR spectroscopy, and bond valence sum calculations. The simple reaction of a mixed-valent closed V12 cage system produced another quasi-closed system composed of two V6 bowl-type cages.

Vanadium(III) phosphonate cage complexes

The synthesis and structural and magnetic characterisation of three new vanadium(III) phosphonate cage complexes are reported. The exchange interactions vary from −30 to +30 cm −1 and appear to be dependent on the superexchange path between vanadium centers.

Convenient Synthesis of Aluminum and Gallium Phosphonate Cages

The reactions of AlCl 3.6H 2O and GaCl 3 with 2-pyridylphosphonic acid (2PypoH 2) and 4-pyridylphosphonic acid (4PypoH 2) afford cyclic aluminum and gallium phosphonate structures of [(2PypoH) 4Al 4(OH 2) 12]Cl 8.6H 2O ( 1), [(4PypoH) 4Al 4(OH 2) 12]Cl 8.11H 2O ( 2), [(2PypoH) 4Al 4(OH 2) 12](NO 3) 8.7H 2O ( 3), [(2PypoH) 2(2Pypo) 4Ga 8Cl 12(OH 2) 4(thf) 2](GaCl 4) 2..8thf ( 4), and [(2PypoH) 2(2Pypo) 4Ga 8Cl 12(OH 2) 4(thf) 2](NO 3) 2.9thf ( 5). Structures 1- 3 feature four aluminum atoms bridged by oxygen atoms from the phosphonate moiety and show structural resemblance to the secondary building units found in zeolites and aluminum phosphates. The gallium complexes, 4 and 5, have eight gallium atoms bridged by phosphonate moieties with two GaCl 4 (-) counterions present in 4 and nitrate ions in 5. The cage structures 1- 3 are interlinked by strong hydrogen bonds, forming polymeric chains that, for aluminum, are thermally robust. Exchange of the phosphonic acid for the more flexible 4PyCH 2PO 3H 2 afforded a coordination polymer with a 1:1 Ga:P ratio, {[(4PyCH 2PO 3H)Ga(OH 2) 3](NO 3) 2.0.5H 2O} x ( 6). Complexes 1- 6 were characterized by single-crystal X-ray diffraction, NMR, and mass spectrometry and studied by TGA.

A Distorted Cubic Tetranuclear Copper(II) Phosphonate Cage with a Double-Four-Ring-Type Core

The reaction of Cu2(O2CMe)(4).2H2O with tert-butylphosphonic acid and 3,5-di-tert-butylpyrazole in the presence of triethylamine leads to a high-yield synthesis of the tetranuclear compound [Cu2(3,5-t-Bu2PzH)2(t-BuPO3)2]2 (1). The latter has a distorted cubic cage structure and its core resembles the D4R (double-four-ring) motif found in zeolites. The phosphonate, [t-BuPO3]2-, functions as a dianionic tridentate ligand, while the pyrazole ligands are neutral and are monodentate. The coordination geometry at each copper atom is distorted square planar with a 3O,1N coordination environment. Magnetic measurements on 1 reveal that the chiT product continuously decreases to reach a value very close to zero at 1.8 K, indicating dominant antiferromagnetic interactions between Cu(II) ions that leads to an S=0 ground state. The tetranuclear cage 1 functions as a very effective artificial nuclease in the presence of an external oxidant, magnesium monoperoxyphthalate.

Synthesis and Structural and Magnetic Characterization of Cobalt(II) Phosphonate Cage Compounds

Reaction of cobalt salts with phosphonic acids in the presence of 6-chloro-2-hydroxypyridine as a co-ligand, normally in its deprotonated form, leads to a series of new polymetallic cobalt cages. The most common structural type is a {Co(14)} cage which resembles a fragment of cobalt hydroxide. Variation of the phosphonate present and the cobalt salt leads to {Co(6)}, {Co(8)}, {Co(10)}, {Co(11)}, {Co(12)}, {Co(13)}, and {Co(20)} cages, all of which have been characterized by X-ray crystallography. Magnetic studies of these cages show a general decline in the product chi(m)T with T, but for {Co(6)}, {Co(8)}, and {Co(12)} there are maxima at low temperature, which suggests nondiamagnetic ground states. Investigation of the dynamic behavior of the magnetization of these complexes shows that the octanuclear cage displays slow relaxation of magnetization.