Crystal and molecular structures of the octakis(pyridine N-oxide) lanthanide complexes M(PyO)8(ClO4)3, M = lanthanum and neodymium

Al-Karaghouli, A. R.; Wood, J.

doi:10.1021/ic50195a001

Cited by 27 publications

(4 citation statements)

References 6 publications

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“…N-oxides of qtpy, like analogous derivatives of pyridine itself , and some cryptands, are known to be good ligands for Ln(III) species (as well as being useful intermediates in ligand synthesis; see subsection , Figure , red frame). Di- and tetroxide derivatives of 75 , ligands 76 and 77 (Figure ), were crystallographically characterized as their eight-coordinate bis(ligand)complexes with Tb(III) and Gd(III), respectively.…”

Section: Architecture Of Qtpy Coordination Complexesmentioning

confidence: 99%

Quaterpyridines as Scaffolds for Functional Metallosupramolecular Materials

et al. 2016

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Quaterpyridine (qtpy) ligands have found significant applications as N-heterocyclic scaffolds in self-assembly processes, in particular the formation of various metallosupramolecular architectures, limited, however, by difficulties in their synthesis. Recent progress in the preparative organic and organometallic chemistry of polypyridines has resulted in the elimination of the most serious drawbacks concerning qtpy synthesis, consequently giving rise to a renewed interest in this class of compounds. Herein, we endeavor to define the essential aspects of quaterpyridine chemistry and provide the reader with a perspective on the ways in which this field has begun to flourish.

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Section: Architecture Of Qtpy Coordination Complexesmentioning

confidence: 99%

Quaterpyridines as Scaffolds for Functional Metallosupramolecular Materials

et al. 2016

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“…The compounds are [R(C s H sNO)s]X3, where the lanthanide ion is at the center of a polyhedron that is close to a square antiprism [93]. The compounds are [R(C s H sNO)s]X3, where the lanthanide ion is at the center of a polyhedron that is close to a square antiprism [93].…”

Section: Some Other Systemsmentioning

confidence: 99%

The Rare Earths or Lanthanides

Carlin

1986

Magnetochemistry

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The paramagnetic properties of the rare earth ions have been investigated so extensively that a book could be written on the subject, never mind a chapter. This is due in large part to the many studies ofthe EPR spectra of the lanthanides when doped into diamagnetic hosts, and the attendant theoretical development in terms of crystal field theory. Many of the current ideas in magnetism have followed from such studies, especially with regard to relaxation phenomena.Relatively few coordination compounds of the lanthanides have been studied in detail. Superexchange is relatively unimportant, and dipole-dipole interactions therefore tend to dominate the magnetic ordering phenomena; this is enhanced by both the relatively large spin and g-values of many ofthe lanthanides. The compounds which order do so largely at temperatures of 4 K and below as a result. These effects are enhanced by the high coordination number of most rare earth compounds, which works to reduce the strength of any superexchange paths. Also, as a result, there appear to be no lower-dimensional rare earth compounds, at least in the sense described in Chap. 7.It is difficult to generalize about each ion, since the crystal field splitting of any ion, though small, can change from one system to another.The chemistry of the lanthanides has been reviewed [1-3]. The distinguishing features for our purposes are:a) The metal ions are found primarily in the trivalent state. b) High coordination numbers (eight appears to be the commonest) and a variety of geometries are found. Six-coordination and lower are rare. Several typical coordination polyhedra are illustrated in Fig. 9.1. c) Oxygen and nitrogen are the favored donor atoms, but a number of halides have also been studied. d) Spin-orbit coupling is important, the more so energetically than crystal field splittings, and increases with atomic number. This is summarized in Table 9.1. The letter " is once again used as the total angular momentum quantum number.e) The magnetic properties are determined by the 4f electrons, which are wellshielded by the occupied outer shells of 5s and 5p electrons. The 4f electrons are littleinvolved with chemical bonding, which is why superexchange is relatively unimportant. This is well-illustrated in Fig. 9.2, which shows the radial extension of the wave functions [6]. The interactions which dominate the cooperative phenomena with rare earth compounds are dipolar in nature. This is because of the important orbital contributions to the magnetic moment. Thus, since dipole-dipole interactions are long-R. L. Carlin, Magnetochemistry

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“…The solvation number of the lanthanide(III) ion in N , N -dimethylformamide (DMF) and N , N -dimethylacetamide (DMA) are reported to be about eight in both solvents, thus lower than the corresponding hydration number in aqueous solution. , The lanthanum(III) ion is solvated by eight dimethyl sulfoxide (DMSO) molecules in the solid [La(OS(CH 3 ) 2 ) 8 ][Cr(NCS) 6 ] with La−O bond distances in the range 2.46−2.51 Å, and by eight pyridine 1-oxide molecules in the solid [La(ONC 5 H 5 ) 8 ](ClO 4 ) 3 with an average La−O bond distance of 2.497 Å in a distorted square antiprism . Our attempts to determine the crystal structures of the solid iodide, perchlorate, and trifluoromethanesulfonate salts with the dimethyl sulfoxide-solvated lanthanum(III) ion have so far failed since the crystals gave too few reflections.…”

Section: Introductionmentioning

confidence: 99%

Steric Effects Control the Structure of the Solvated Lanthanum(III) Ion in Aqueous, Dimethyl Sulfoxide, andN,N‘-Dimethylpropyleneurea Solution. An EXAFS and Large-Angle X-ray Scattering Study

et al. 2000

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The structure of the solvated lanthanum(III) ion has been determined in aqueous, dimethyl sulfoxide, and N,N'-dimethylpropyleneurea solution by means of the EXAFS and large-angle X-ray scattering (LAXS) techniques. The close agreement between the EXAFS spectra of solid nonaaqualanthanum(III) trifluoromethanesulfonate and of an aqueous lanthanum(III) perchlorate solution shows that the hydrated lanthanum(III) ion in aqueous solution most probably has the same structure as in the solid, i.e., nine water molecules coordinated in a tricapped trigonal prismatic configuration. The data analysis from EXAFS and LAXS measurements of the aqueous solution resulted in the La-O bond distances 2.52(2) and 2.65(3) A to the water molecules in the prism and the capping positions, respectively. The LAXS study shows a second hydration sphere consistent with approximately 18 water molecules at 4.63(2) A. The EXAFS spectra of solid octakis(dimethyl sulfoxide)lanthanum(III) trifluoromethanesulfonate and a dimethyl sulfoxide solution of this salt are also similar. The data analysis of EXAFS and LAXS measurements assuming eight-coordination around lanthanum yielded an La-O bond distance of 2.50(2) A, and an La...S distance of 3.70(3) A, giving an La-O-S angle of 133(2) degrees. The EXAFS data of an N,N'-dimethylpropyleneurea solution of lanthanum(III) trifluoromethanesulfonate gave the La-O bond distance 2.438(4) A and the La...C distance 3.41(2) A, which correspond to an La-O-C angle of 131(2) degrees. The La-O bond distance is consistent with seven-coordination around lanthanum, on the basis of the variation of the ionic radii of the lanthanum(III) ion with different coordination numbers.

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Crystal and molecular structures of the octakis(pyridine N-oxide) lanthanide complexes M(PyO)8(ClO4)3, M = lanthanum and neodymium

Cited by 27 publications

References 6 publications

Quaterpyridines as Scaffolds for Functional Metallosupramolecular Materials

Quaterpyridines as Scaffolds for Functional Metallosupramolecular Materials

The Rare Earths or Lanthanides

Steric Effects Control the Structure of the Solvated Lanthanum(III) Ion in Aqueous, Dimethyl Sulfoxide, andN,N‘-Dimethylpropyleneurea Solution. An EXAFS and Large-Angle X-ray Scattering Study

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