Bis{2-[1-(thiosemicarbazono)ethyl]pyridinium} hexakis(nitrato-<i>O</i>,<i>O</i>')thorate(IV) tetramethanol solvate

Abram, U.; Bonfada, Élida; Lang, Ernesto Schulz

doi:10.1107/s0108270199007556

Cited by 10 publications

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“…Its elemental analysis agrees with the proposed formula (see Experimental Section), and its 1 H NMR spectrum in DMSO is coherent with the presence of the H 2 AcPyTSC + cation. Furthermore, metal complexes containing the counterion [H 2 AcPyTSC] + have been reported previously. , Since the protonation constants of HAcPyTSc and HPyTSC are almost identical, , it is plausible that a similar complex containing [H 2 PyTSC] + may have been formed in the reaction of PbPh 2 Cl 2 with HPyTSC, in which case its nonisolation might be due to it being more instead of less soluble than [PbPh 2 Cl(PyTSC)] ([H 2 PyTSC]Cl is more soluble than [H 2 AcPyTSC]Cl in MeOH according to our approximate measurements).…”

Section: Resultsmentioning

confidence: 99%

Compositional and Structural Variety of Diphenyllead(IV) Complexes Obtained by Reaction of Diphenyllead Dichloride with Thiosemicarbazones

et al. 2003

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The reactions of PbPh(2)Cl(2) in methanol with acetophenone, salicylaldehyde, pyridine-2-carbaldehyde, 2-acetylpyridine, and 2-benzoylpyridine thiosemicarbazones (HATSC, HSTSC, HPyTSC, HAcPyTSC, and HBPyTSC, respectively) were explored. Despite the similarities among these ligands, the reactions afforded solids with very diverse compositions and structural characteristics, which were in most cases analyzed by X-ray diffractometry (as was the structure of the free ligand HBPyTSC). In the complexes [PbPh(2)Cl(2)(HATSC)](2), [PbPh(2)Cl(2)(HSTSC)(2)], [(PbPh(2)Cl(HPyTSC)(2))][PbPh(2)Cl(3)(MeOH)](2), and [PbPh(2)Cl(PyTSC)] the metal atoms are surrounded by more or less distorted octahedral coordination polyhedra; if both strong and weak interactions are considered, the lead atom in [PbPh(2)Cl(AcPyTSC)] has coordination number 7 and distorted pentagonal bipyramidal coordination geometry, while [(PbPh(2)(BPyTSC))(2)(PbPh(2)Cl(4))].2MeOH contains two different types of lead atom, one with octahedral and the other with pentagonal bipyramidal coordination. The complexes (H(2)AcPyTSC)[PbPh(2)Cl(3)] and [PbPh(2)Cl(HAcPyTSC)][PbPh(2)Cl(3)], which were also isolated, could not be crystallized. All these complexes are soluble in DMSO, and the compositions of these solutions were investigated using conductivity measurements and (1)H and (207)Pb NMR spectroscopy.

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Section: Resultsmentioning

confidence: 99%

Compositional and Structural Variety of Diphenyllead(IV) Complexes Obtained by Reaction of Diphenyllead Dichloride with Thiosemicarbazones

et al. 2003

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“…It is well known that regular icosahedral structures with N =12 in the first coordination sphere are particularly stable and are found, for example, in rare‐gas clusters and in a number of metallic clusters 5. Such high coordination numbers are also found in actinide complexes, for example in [U(NO 3 ) 6 ] 2− 6 and [Th(NO 3 ) 6 ] 2− 7. In the solid state, coordination numbers up to N max =12 (hexagonal closed packing and face‐centered cubic) are realized, and high coordination numbers usually imply denser packing.…”

Section: Minimum Maximum and Average Pbhe Distances And Average Hmentioning

confidence: 98%

The Search for the Species with the Highest Coordination Number

2007

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The question of the highest possible coordination number for an atom is addressed as this is related to the Gregory-Newton problem of kissing hard spheres.[1] Using first-principles quantum chemical simulations we show that the interaction of Pb 2+ with He atoms results in remarkably stable PbHe 15 2+with 15 atoms in the first coordination sphere forming a Frank-Kasper polyhedron.[2] The PbÀHe distances do not change significantly by subsequent filling of the first coordination shell as one expects for a hard-sphere model. Such high coordination numbers have been proposed only in liquid simulations so far. [3] The problem of how many spheres (N max , called the kissing number or Newton number) of a given radius R can be packed around a unit sphere in n dim dimensions is called the generalized Gregory-Newton problem. In three dimensions, if all spheres have the same radius, the answer is well known: N max = 12.[1] The extension to general dimensions (with the exception of n dim = 1, 2, 3, 8, and 24), or the kissing-number problem of spheres with radius R on a unit sphere, remains unsolved. [1] In chemistry N max corresponds to the maximum coordination number of ligands interacting with a central atom, as pointed out as early as 1875 by Günther.[4] Herein we assume that the ligands do not interact strongly with each other. Hence this excludes systems like M@C 60 , which would have N max = 60 but are better described as an atom trapped in a fullerene cage.It is well known that regular icosahedral structures with N = 12 in the first coordination sphere are particularly stable and are found, for example, in rare-gas clusters and in a number of metallic clusters.[ . [7] In the solid state, coordination numbers up to N max = 12 (hexagonal closed packing and face-centered cubic) are realized, and high coordination numbers usually imply denser packing. In liquid-metal simulations, coordination numbers as high as 16 or higher have been postulated but only for a very short timeframe. [3,8] In binary intermetallic alloys local coordination numbers of 14, 15, and even 16 are predicted; prime examples are FriaufLaves phases in MgZn 2 or MgNi 2 .[9] Frank and Kasper showed that the frequent use of icosahedral coordination will occur in conjunction with coordination numbers higher than 12 stabilized by the surrounding matrix.[2]Herein we take a different approach. We look for a single molecule MX N in the gas phase of high coordination number N which can be experimentally verified. We choose a large positively charged central atom, M = Pb 2+, and a very small ligand, X = He. Both atoms have reasonably small polarizabilities (a He = 1.38 au [10] and a Pb 2+ = 14.1 au [11] ), and therefore fit the hard-sphere model quite well. The ionization potential of Pb + (15.03 eV) is much smaller than that of He (24.58 eV).[12] Hence, Pb 2+ÀHe does not undergo a Coulomb explosion and there is no (or minimal) charge transfer from He to Pb 2+ . Hence the Pb 2+ -He interaction V(R) is mainly of charge-induced-dipole (CID) nature [Eq. (1) with ...

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“…It is knownt hat actinidei ons form complexes with high CNs. Amongt hose founde xperimentally are twelve-coordinated uranium in [U(NO 3 ) 6 ] 2À , [7] twelve-coordinated thorium in [Th(NO 3 ) 6 ] 2À , [8] fourteen-coordinated uranium in U(BH 4 ) 4 , [9] and fifteen-coordinated thorium in Th(H 3 BNMe 2 BH 3 ) 4 . [10] Ar ecent quantum chemical study by Kaltsoyannis [11] reported ar ecord-high coordination number of 17 for actinide-helium com-plexesA c 3 + -He 17 ,Th 4 + -He 17 ,and Pa 4 + -He 17 .…”

Section: Introductionmentioning

confidence: 99%

Quantum Simulation Verifies the Stability of an 18‐Coordinated Actinium–Helium Complex

Ozama

Adachi

Takayanagi

et al. 2018

Chemistry A European J

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Structures of a trivalent actinium cation in helium clusters (Ac ⋅He ) have been studied by quantum path integral molecular dynamics simulations with different cluster sizes, n=18-200. The nuclear quantum effect of helium atoms plays an important role in the vibrational amplitude of the Ac -He complex at low temperatures (1-3 K) at which the complex is stable. We found that the coordination number of helium atoms comprising the first solvation shell can be as high as eighteen. In this case, the helium atoms are arranged in D symmetry. The Ac -He complex becomes more rigid as the cluster increases in size, which implies that it becomes more stable. The simulation results are based on an accurate description of the Ac -He interaction using relativistic ab initio calculations.

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Bis{2-[1-(thiosemicarbazono)ethyl]pyridinium} hexakis(nitrato-O,O')thorate(IV) tetramethanol solvate

Cited by 10 publications

References 0 publications

Compositional and Structural Variety of Diphenyllead(IV) Complexes Obtained by Reaction of Diphenyllead Dichloride with Thiosemicarbazones

Compositional and Structural Variety of Diphenyllead(IV) Complexes Obtained by Reaction of Diphenyllead Dichloride with Thiosemicarbazones

The Search for the Species with the Highest Coordination Number

Quantum Simulation Verifies the Stability of an 18‐Coordinated Actinium–Helium Complex

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