Aspects of the Stereochemistry of Seven‐Coordination

Kepert, David L.

doi:10.1002/9780470166260.ch2

Cited by 70 publications

(4 citation statements)

References 126 publications

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“…The Ta−C bond distances (Å) fall into the 1:3:3 pattern expected of a capped octahedron, where C(37) caps a trigonal face defined by C(10), C(28), and C(46), i.e., Ta−C(37) 2.103(5) (cap); Ta−C(10) 2.163(6), Ta−C(28) 2.144(5), Ta−C(46) 2.155(5) (capped face); and Ta−C(1) 2.194(5), Ta−C(19) 2.200(5), Ta−C(55) 2.214(6) (uncapped face). Also, the capping Ta−C(37) bond vector is practically perpendicular (89°) to the capped trigonal face, where an angle of 90° is expected for an ideal capped octahedron . Although the arrangement of the CNXyl ligands about the tantalum is likely to be influenced by steric repulsions of these bulky substituents, it is interesting to note that the geometry of the TaC 7 core in 2 is strikingly similar to that of the MoC 7 core of [Mo(CNMe) 7 ] 2+ .…”

Section: Resultsmentioning

confidence: 92%

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

et al. 2007

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Treatment of [M(CO)(6)](-), M = Nb, Ta, with Ag(+), I(2) or NO(+) in the presence of CNXyl provided [M(CNXyl)(7)](+), M(CNXyl)(6)I, or cis-[M(CNXyl)(4)(NO)(2)](+), which are isocyanide analogues of the unknown carbonyl complexes [M(CO)(7)](+), M(CO)(6)I, or cis-[M(CO)(4)(NO)(2)](+), respectively. Reduction of M(CNXyl)(6)I by cesium graphite gave the respective Cs[M(CNXyl)(6)], which have been structurally characterized and represent the first isolable homoleptic isocyanidemetalates for second or third row transition metals. Nitrosylation of [Ta(CNXyl)(6)](-) affords a rare example of a mononitrosyl tantalum complex, Ta(CNXyl)(5)NO, which is an isocyanide analogue of the unknown Ta(CO)(5)NO. This study emphasizes, inter alia, the remarkable versatility of the CNXyl ligand compared to CO in stabilizing various electronic environments at heavier group 5 metal centers.

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Section: Resultsmentioning

confidence: 92%

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

et al. 2007

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“…The copper cation is seven-coordinated by two bidentate chelating dmp anions, two monodentate hmta molecules, and one monodentate water ( Figure 1 a). The coordination polyhedron is a distorted pentagonal bipyramid [ 21 ], in which both apexes are occupied by nitrogen atoms of hmta ( Figure 1 b,c). A strong asymmetricity of coordination bonds between copper ion and chelating dmp anions is observed ( Table 1 ).…”

Section: Resultsmentioning

confidence: 99%

Copper(II) 2,2-Bis(Hydroxymethyl)Propionate Coordination Compounds with Hexamethylenetetramine: From Mononuclear Complex to One-Dimensional Coordination Polymer

Rauf

Trzęsowska-Kruszyńska

Sierański

et al. 2021

Molecules

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Three new copper coordination compounds derived from 2,2-bis(hydroxymethyl)propionic acid (dmpa) and hexamethylenetetramine (hmta) were obtained and their crystal structures were determined. The stoichiometry of the reagents applied in the syntheses reflects the metal to ligand molar ratio in the formed solid products. Due to the multiple coordination modes of the used ligands, wide structural diversity was achieved among synthesized compounds, i.e., mononuclear [Cu(dmp)2(hmta)2(H2O)] (1), dinuclear [Cu2(dmp)4(hmta)2] (2), and 1D coordination polymer [Cu2(dmp)4(hmta)]n (3). Their supramolecular structures are governed by O—H•••O and O—H•••N hydrogen bonds. The compounds were characterized in terms of absorption (UV-Vis and IR) and thermal properties. The relationships between structural features and properties were discussed in detail. Owing to discrepancies in the coordination mode of a dmp ligand, bidentate chelating in 1, and bidentate bridging in 2 and 3, there is a noticeable change in the position of the bands corresponding to the stretching vibrations of the carboxylate group in the IR spectra. The differences in the structures of the compounds are also reflected in the nature and position of the UV-Vis absorption maxima, which are located at lower wavelengths for 1.

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“…The uranium atoms are seven-coordinated by two imine nitrogen atoms, two alkoxide oxygen atoms, two oxide oxygen atoms and one oxygen atom of solvent molecule. The coordination environment of the metal atoms can be described as slightly distorted pentagonal bipyramid13 with the oxide oxygen atoms located at the polyhedron apexes. The presented compounds are the first example of usage of the N’-bis(2-hydroxybenzylidene)-2,2-dimethyl-1,3-propanediamine as a building block for construction of coordination sphere with coordination number equal to 7.…”

Section: Discussionmentioning

confidence: 99%

Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

Azam

Velmurugan

Wabaidur

et al. 2016

Sci Rep

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Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2′-(1E,1′E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion. TD-DFT results indicate that the complex 1 displays an intense band at 458.7 nm which is mainly associated to the uranyl centered LMCT, where complex 2 shows a band at 461.8 nm that have significant LMCT character. The bonding has been further analyzed by EDA and NBO. The photocatalytic activity of complexes 1 and 2 for the degradation of rhodamine-B (RhB) and methylene blue (MB) under the irradiation of 500W Xe lamp has been explored, and found more efficient in presence of complex 1 than complex 2 for both dyes. In addition, dye adsorption and photoluminescence properties have also been discussed for both complexes.

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Aspects of the Stereochemistry of Seven‐Coordination

Cited by 70 publications

References 126 publications

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

Copper(II) 2,2-Bis(Hydroxymethyl)Propionate Coordination Compounds with Hexamethylenetetramine: From Mononuclear Complex to One-Dimensional Coordination Polymer

Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

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Aspects of the Stereochemistry of Seven‐Coordination

Cited by 70 publications

References 126 publications

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)6]-, [Ta(CNXyl)6]-, and Derivatives Thereof1

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)6]-, [Ta(CNXyl)6]-, and Derivatives Thereof1

Copper(II) 2,2-Bis(Hydroxymethyl)Propionate Coordination Compounds with Hexamethylenetetramine: From Mononuclear Complex to One-Dimensional Coordination Polymer

Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

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Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹