Niobium(III) chloride

Niobium(III) chloride
Identifiers
CAS Number	13569-59-0;
3D model (JSmol)	Interactive image; 1,2-dimethoxyethane complex:Interactive image;
ChemSpider	75410;
ECHA InfoCard	100.033.608
EC Number	236-985-0;
PubChemCID	11542954; 1,2-dimethoxyethane complex:6096194;
CompTox Dashboard(EPA)	DTXSID3065536;
	InChI InChI=1S/3ClH.Nb/h31H;/q;;;+3/p-3 Key: VPDYSPXEGTXWEU-UHFFFAOYSA-K; 1,2-dimethoxyethane complex: InChI=1S/C4H10O2.3ClH.Nb/c1-5-3-4-6-2;;;;/h3-4H2,1-2H3;31H;/q;;;;+3/p-3 Key: SBSZUBUHOUKQMN-UHFFFAOYSA-K;
	SMILES [Cl-].[Cl-].[Cl-].[Nb+3]; 1,2-dimethoxyethane complex: COCCOC.Cl[Nb](Cl)Cl;
Properties
Chemical formula	Cl3Nb
Molar mass	199.26g·mol−1
Appearance	black solid
Density	3.75
Structure
Crystal structure	hexagonal
Space group	P3m1
Lattice constant	a= 6.744,c= 12.268
Formula units(Z)	2
	Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa). Infobox references

Niobium(III) chloridealso known asniobium trichlorideis a compound ofniobiumandchlorine.The binary phase NbCl₃is not well characterized but manyadductsare known.

Synthesis

Structure of NbCl₃(dimethoxyethane)(3-hexyne).^[2]

Nb₃Cl₈is produced by reduction ofniobium(V) chloridewithhydrogen,or just by heating.

Salt-free reductionof dimethoxyethane solution of NbCl₅with 1,4-disilyl-cyclohexadiene in the presence of3-hexyneproduces thecoordination complexNbCl₃(dimethoxyethane)(3-hexyne):

NbCl₅+ C₆H₆(SiMe₃)₂+ C₂Et₂+ dme → NbCl₃(dme)(C₂Et₂) + C₆H₆+ 2 Me₃SiCl

An impuredimethoxyethane(dme) adduct of niobium trichloride was produced by reduction of a dme solution of niobium pentachloride withtributyltin hydride:^[3]

NbCl₅+ 2 Bu₃SnH + MeOCH₂CH₂OMe → NbCl₃(MeOCH₂CH₂OMe) + 2 Bu₃SnCl

Structure

Nb₃Cl₈has ahexagonal close packedarray of chloride ions. Triangles of niobium occur in octahedral spaces in the chloride array. The compositions with higher chloride have some niobium atoms missing from the structure, creating vacancies and giving rise tononstoichiometric compounds.NbCl₄has this pattern of vacancies stretched until the niobium atoms are in pairs rather than triangles. So NbCl₃can be considered as a solid solution of Nb₃Cl₈and Nb₂Cl₈.^[4]

The colour of niobium trichloride varies depending on the niobium:chloride ratio. NbCl_2.67is green, while NbCl_3.13is brown.^[1]

Reactions

When heated to over 600 °C niobium trichloride disproportionates to niobium metal and niobium pentachloride.

Adducts

NbCl₃(dimethoxyethane) has received significant attention as a reagent for reductive coupling of carbonyls and imines.^[6]It is sold as a1,2-dimethoxyethanecomplex. Nb(III) adducts are also known for1,4-dioxaneanddiethyl ether.

Niobium(III) chloride forms a series of compounds with the formula Nb₂Cl₆L_xwith Nb=Nbdouble bond.Withtertiary phosphinesand arsines, the complexes are edge-share bioctahedra, e.g., Nb₂Cl₆(PPhMe₂)₄.^[7] Thioethers form adducts with one bridging thioether (R₂S). These face-sharing bioctahedra have the formula Nb₂X₆(R₂S)₃(X = Cl, Br).

References

^^a ^bGutmann, Viktor (1967).Halogen Chemistry.Elsevier. p. 157.ISBN 978-0-323-14847-4.
^Tsurugi, Hayato; Mashima, Kazushi (2019). "Salt-Free Reduction of Transition Metal Complexes by Bis(trimethylsilyl)cyclohexadiene, -dihydropyrazine, and -4,4′-bipyridinylidene Derivatives".Accounts of Chemical Research.52(3): 769–779.doi:10.1021/acs.accounts.8b00638.PMID 30794373.S2CID 73505603.
^Pedersen, Steven F.; Hartung, Jack B.; Roskamp, Eric J.; Dragovich, Peter S. (1992). "Niobium(III) and (IV) Halide Complexes".Inorganic Syntheses.Vol. 28. pp. 119–123.doi:10.1002/9780470132609.ch28.ISBN 9780470132609.
^Cotton, F. Albert; Wilkinson, Geoffrey (1966).Advanced Inorganic Chemistry: A Comprehensive Text.John Wiley. p. 927.
^Kakeya, Masaki; Fujihara, Takashi; Nagasawa, Akira (2006). "Di-μ-chloro-μ-(dimethyl sulfide)-bis[dichloro(dimethyl sulfide)niobium(III)]".Acta Crystallographica Section E.62(3): m553–m554.Bibcode:2006AcCrE..62M.553K.doi:10.1107/S1600536806005149.
^Roskamp, Carrie A.; Roskamp, Eric J. (2001). "Trichloro(1,2-dimethoxyethane)niobium".Encyclopedia of Reagents for Organic Synthesis.doi:10.1002/047084289X.rt202s.ISBN 0471936235.
^Sharma, Sangeeta; Vermani, O. P.; Narula, A. K. (January 1996)."Synthesis and Structural Studies of Complexes of Niobium(III) Chloride with Ditertiary Phosphines".Indian Journal of Chemistry, Section A.35A(1).ISSN 0975-0975.

[gut-1] Gutmann, Viktor (1967).Halogen Chemistry.Elsevier. p. 157.ISBN 978-0-323-14847-4.

[2] Tsurugi, Hayato; Mashima, Kazushi (2019). "Salt-Free Reduction of Transition Metal Complexes by Bis(trimethylsilyl)cyclohexadiene, -dihydropyrazine, and -4,4′-bipyridinylidene Derivatives".Accounts of Chemical Research.52(3): 769–779.doi:10.1021/acs.accounts.8b00638.PMID 30794373.S2CID 73505603.

[3] Pedersen, Steven F.; Hartung, Jack B.; Roskamp, Eric J.; Dragovich, Peter S. (1992). "Niobium(III) and (IV) Halide Complexes".Inorganic Syntheses.Vol. 28. pp. 119–123.doi:10.1002/9780470132609.ch28.ISBN 9780470132609.

[4] Cotton, F. Albert; Wilkinson, Geoffrey (1966).Advanced Inorganic Chemistry: A Comprehensive Text.John Wiley. p. 927.

[5] Kakeya, Masaki; Fujihara, Takashi; Nagasawa, Akira (2006). "Di-μ-chloro-μ-(dimethyl sulfide)-bis[dichloro(dimethyl sulfide)niobium(III)]".Acta Crystallographica Section E.62(3): m553–m554.Bibcode:2006AcCrE..62M.553K.doi:10.1107/S1600536806005149.

[6] Roskamp, Carrie A.; Roskamp, Eric J. (2001). "Trichloro(1,2-dimethoxyethane)niobium".Encyclopedia of Reagents for Organic Synthesis.doi:10.1002/047084289X.rt202s.ISBN 0471936235.

[7] Sharma, Sangeeta; Vermani, O. P.; Narula, A. K. (January 1996)."Synthesis and Structural Studies of Complexes of Niobium(III) Chloride with Ditertiary Phosphines".Indian Journal of Chemistry, Section A.35A(1).ISSN 0975-0975.

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