Vibrational assignment and normal coordinate analysis of [MOF5]2− (M = Nb, Ta) in the modified Urey-Bradley force field

Surendra, L.; Sathyanarayana, D. N.; Jere, G.V.

doi:10.1016/s0022-1139(00)84974-x

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…It is difficult to definitively distinguish oxide and fluoride anions by X-ray crystallography, owing to their similar polarizability and ionic radii. ,, To validate that the oxide-fluoride/fluoride BBUs in compounds 1 – 3 are [TaOF 5 ] 2– , [TaF 6 ] − , and [TaF 7 ] 2– , respectively, we employed FT-IR spectroscopy. The infrared spectrum of 1 (Figure a) show three strong characteristic bands for [TaOF 5 ] 2– at ν s (TaO) = 867 cm –1 and ν s (Ta–F) = 583, 540 cm –1 (with a shoulder at 568 cm –1 ), respectively. , The remaining vibrations may be assigned to 2,2′-bipyridyl (see Figure S1a of the Supporting Information ). The infrared spectrum of 2 (Figure b) show two strong characteristic bands for [TaF 6 ] − at v s (Ta–F) = 597, 539 cm –1 (with a shoulder at 526 cm –1 ) .…”

Section: Resultsmentioning

confidence: 99%

Specific Chemistry of the Anions: [TaOF₅]^2–, [TaF₆]⁻, and [TaF₇]^2–

Gautier

Donakowski

et al. 2014

Crystal Growth & Design

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The controlled crystallization of specific tantalum oxide-fluoride and tantalum fluoride anions ([TaOF 5 ] 2− , [TaF 6 ] − , and [TaF 7 ] 2− ) is demonstrated using organic reagents with varied corresponding pK a values in the presence of aqueous hydrofluoric acid. The identity of tantalum oxide-fluoride or fluoride anions of [TaOF 5 ] 2− , [TaF 6 ] − , and [TaF 7 ] 2− are shown to crystallize successively from solution to solid state by increasing the corresponding pK a of organic reagents, which lead to the subsequent increase of fluoride concentration in the hydrofluoric acid solution.With the use of this methodology, three new hybrid crystal structures were targeted: [H 2 (2,2′-bpy)]TaOF 5 (2,2′-bpy = 2,2′-bipyridyl) 1, [Hdpa]TaF 6 (dpa = 2,2′-dipyridylamine) 2, and [H 2 En]TaF 7 (En = ethylenediamine) 3, respectively. The applicability and comparison of this methodology for tantalum and previously prepared niobium compounds show that it can be broadly used to design new materials with specific functionalities for other transition metal oxide-fluorides. ■ INTRODUCTIONHigh second-order nonlinear optical (NLO) response in noncentrosymmetric (NCS) structures often are generated from asymmetric basic building units (BBUs), such as anionic groups with π-orbital systems or stereochemically active lone pairs [(BO 3 ) 3− , (B 3 O 6 ) 3− , (IO 3 ) − , (TeO x ) n− , [AsS 3 ] 3− , [SbS 3 ] 3− , etc.] 1−7 and second-order Jahn−Teller (SOJT) distorted d 0 transition metal centers (Ti 4+ , Nb 5+ , Ta 5+ , Mo 6+ , etc.). 8−12 Materials with potentially higher second-harmonic generation (SHG) efficiencies based on the concept of two combined acentric BBUs have been shown to crystallize in one NCS structure, either by the combination of acentric cations and acentric anions 13−15 or combination of two acentric anions. 8,16−19 Thus, to incorporate specific acentric BBUs into NCS structures, a rational synthetic approach to target the crystallization of specific anions is needed.Tantalum compounds with strong SHG responses have been recently reported. 16 Owing to the good solubility of tantalum oxide in hydrofluoric acid solutions, tantalum oxide-fluoride/ fluoride anions similar to other early transition metal oxidefluoride anions have been extensively examined. 20−23 Previous tantalum compounds with different tantalum oxide-fluoride/ fluoride anions (e.g., [ TaOF 5 ] 2− , 24,25 [Ta(O 2 )F 5 ] 2− , 26,27 [TaF 6 ] − , 28 [TaF 7 ] 2− , 29−33 [Ta 2 OF 10 ] 2− dimer 34 and the adamantine-like cage [Ta 4 O 6 F 12 ] 2− anions 35 ) have been reported for their diverse coordination chemistry and interesting properties. Solution-phase NMR, Raman, and IR spectroscopy at room temperature have shown that different tantalum oxide-fluoride/fluoride species exist in different fluoride concentration conditions. 36−41 However, the controlled crystallization of specific tantalum oxide-fluoride/ fluoride anions has not been studied so far. In this article, to better understand specific chemistry of tantalum and target potential acentric units of ...

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Section: Resultsmentioning

confidence: 99%

Specific Chemistry of the Anions: [TaOF₅]^2–, [TaF₆]⁻, and [TaF₇]^2–

Gautier

Donakowski

et al. 2014

Crystal Growth & Design

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“…Very strong bands in the range of 880–960 cm –1 are assigned to the Nb–terminal O stretching vibration. Normal coordinate analysis of isolated NbOF 5 2– ( C 4 v symmetry) was made and compared with experimental spectra of A 2 NbOF 5 (A = Rb, Cs) and K 2 NbOF 5 ·H 2 O . The range of 900–940 cm –1 is characteristic for ν 1 (A 1 ) Nb–O stretching vibration, which is both IR- and Raman-active.…”

Section: Results and Interpretationmentioning

confidence: 99%

“…The second-moment calculations of NMR spectra (S 2 in G 2 ) were carried out by the original program with the use of formulas presented elsewhere. 17 2− (C 4v symmetry) was made 18 and compared with experimental spectra of A 2 NbOF 5 (A = Rb, Cs) 19 and K 2 NbOF 5 •H 2 O. 20 The range of 900−940 cm −1 is characteristic for ν 1 (A 1 ) Nb−O stretching vibration, which is both IR-and Raman-active.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Bonding and Structure of Oxofluoroniobate-Based Glasses

et al. 2013

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Glasses based on the oxofluoroniobate anion have been characterized by vibrational and solid-state NMR spectroscopy. The mechanism of glass formation in the systems K2NbOF5-MF3 (M = Al, In) has been suggested. A glass network is built from the chains of corner-sharing octahedra through -Nb-F(O)-M- and -Nb-F-Nb- bridges. Isolated NbOF5(2-) octahedra are also present, which is consistent with the glass composition. The high ionic mobility of NbOF5(2-) due to its fast reorientations results in equalization of the Nb-O and Nb-F distances, which is reflected in the appearance of the IR band at 700-800 cm(-1) not observed in the Raman spectrum. Its assignment to bridging -Nb-O-Nb- species accepted in the literature was not proven.

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“…To verify that the oxyfluorides in compounds 1 – 3 are [Ta 2 OF 10 ] 2– and [Ta 4 O 4 F 16 ] 4– , [Ta 6 O 9 F 18 ] 6– , and [TaOF 4 ] − , respectively, FTIR spectroscopy was conducted (Figure ). The infrared spectrum of 1 shows that the νs (TaO) and νs (TaF) of [Ta 2 OF 10 ] 2– and [Ta 4 O 4 F 16 ] 4– are divided into 886, 536, and 581 cm –1 , with a shoulder peak of 556 cm –1 . , The band in the 400–800 cm –1 region may be ascribed to the Ta–O–Ta stretching mode . The remaining vibrations in 1 can be assigned to organic cations (quinuclidinium).…”

Section: Resultsmentioning

confidence: 99%

“…The infrared spectrum of 1 shows that the νs (Ta�O) and νs (Ta�F) of [Ta 2 OF 10 ] 2− and [Ta 4 O 4 F 16 ] 4− are divided into 886, 536, and 581 cm −1 , with a shoulder peak of 556 cm −1 . 29,30 The band in the 400−800 cm −1 region may be ascribed to the Ta−O−Ta stretching mode. 31 The remaining vibrations in 1 can be assigned to organic cations (quinuclidinium).…”

Section: Synthesis Of [C 6 H 5 Nh 3 ][Taof 4 ] (3)mentioning

confidence: 99%

Controlling the Assembly of Tantalum Oxyfluoride Anions by Organic Amine Cations: From Molecular Cluster, Molecular Cage to Polymeric Chain

Wang

et al. 2023

Crystal Growth & Design

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Three tantalum oxyfluorides, with structures ranging from molecular cluster, molecular cage to polymeric chain, were synthesized by using organic cations as structure-directing agents in the presence of aqueous hydrofluoric acid. Single-crystal X-ray analysis reveals that compoundn− in which oxygen atoms act as bridging ligands. Notably, compound 1 is the first tantalum oxyfluoride comprising mixed discrete anionic tantalum oxyfluoride clusters, while compound 2 features a rare molecular cage with a Ta 6 trigonal prism structure.

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Vibrational assignment and normal coordinate analysis of [MOF5]2− (M = Nb, Ta) in the modified Urey-Bradley force field

Cited by 8 publications

References 15 publications

Specific Chemistry of the Anions: [TaOF₅]^2–, [TaF₆]⁻, and [TaF₇]^2–

Specific Chemistry of the Anions: [TaOF₅]^2–, [TaF₆]⁻, and [TaF₇]^2–

Bonding and Structure of Oxofluoroniobate-Based Glasses

Controlling the Assembly of Tantalum Oxyfluoride Anions by Organic Amine Cations: From Molecular Cluster, Molecular Cage to Polymeric Chain

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Vibrational assignment and normal coordinate analysis of [MOF5]2− (M = Nb, Ta) in the modified Urey-Bradley force field

Cited by 8 publications

References 15 publications

Specific Chemistry of the Anions: [TaOF5]2–, [TaF6]−, and [TaF7]2–

Specific Chemistry of the Anions: [TaOF5]2–, [TaF6]−, and [TaF7]2–

Bonding and Structure of Oxofluoroniobate-Based Glasses

Controlling the Assembly of Tantalum Oxyfluoride Anions by Organic Amine Cations: From Molecular Cluster, Molecular Cage to Polymeric Chain

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Product

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Specific Chemistry of the Anions: [TaOF₅]^2–, [TaF₆]⁻, and [TaF₇]^2–

Specific Chemistry of the Anions: [TaOF₅]^2–, [TaF₆]⁻, and [TaF₇]^2–