Chemistry:Transition metal ether complex

From HandWiki
Structure of the ether complex HfCl4(thf)2.[1]

In chemistry, a transition metal ether complex is a coordination complex consisting of a transition metal bonded to one or more ether ligand. The inventory of complexes is extensive.[2] Common ether ligands are diethyl ether and tetrahydrofuran. Common chelating ether ligands include the glymes, dimethoxyethane (dme) and diglyme, and the crown ethers. Being lipophilic, metal-ether complexes often exhibit solubility in organic solvents, a property of interest in synthetic chemistry. In contrast, the di-ether 1,4-dioxane is generally a bridging ligand.

Bonding, structure, reactions

In almost all of its complexes, dioxane is a bridging, not chelating, ligand. Structure of the coordination polymer of cobalt(II) chloride and 1,4-dioxane.[3]

Ethers are L-type ligands. They are σ-donors that exert weak field ligands. They resemble water ligands as seen in aquo complexes. They do not, however, readily participate in hydrogen bonding. The ether oxygen is nearly trigonal planar in its complexes.[4]

Being weakly basic, ether ligands tend to be easily displaceable. Otherwise, ether ligands are relatively unreactive. Cyclic ethers such as thf can ring-open or even deoxygenated when bound to highly electrophilic metal halides. Thus treatment of tungsten hexachloride with one equivalent of thf gives 1,4-dichlorobutane:[5]

WCl
6
+ OC
4
H
8
→ WOCl
4
+ ClCH
2
CH
2
CH
2
CH
2
Cl

At higher concentrations of thf, polytetrahydrofuran is produced.

Examples

Homoleptic complexes

Ethers are relatively bulky ligands, thus homoleptic (i.e., all ligands being the same) ether complexes are uncommon. Examples often feature weakly coordinating anions such as BArF4 and Al(ORF)4.

  • [V(thf)6](BArF4)2[6]
  • [Mn(thf)6](Mn(CO)5]2[7]
  • Fe(thf)6[BArF24]2[8]
  • [Ni(thf)6][Al(ORF)4 ]2[9]

Metal halide complexes

Structure of NiI2(dme)2 as determined by X-ray crystallography. The sum of the angles at O is 352°, indicating a nearly planar ether oxygen. Color code: O = red, I = purple, Ni = blue, C = black.[10]
Structure of FeCl3(diethylether)2.[11] Color code: Cl=green,Fe = blue, O = red.

Metal chloride-tetrahydrofuran complexes are especially studied.[12] These compounds are often reagents because they are soluble in organic solvents as well as being anhydrous.

Formula of
Metal-Chloride-ether Complexes
Coordination
sphere
color
TiCl4(thf)2 TiO2Cl4 yellow[13]
TiCl3(thf)3 TiO3Cl3 blue[12]
[TiCl3(thf)2]2 TiO2Cl4 green[14]
ZrCl4(thf)2 ZrO2Cl4 white[12]
HfCl4(thf)2 HfO2Cl4 white[12]
VCl3(thf)3 VO3Cl3 pink[12]
VCl3(thf)2]2 VO2Cl4 red[14]
NbCl4(thf)2 NbO2Cl4 yellow[15]
Ta3Cl9(thf)4 TaO2Cl4 and TaOCl5[15]
CrCl3(thf)3 CrO3Cl3 pink[12][16]
MoCl4(thf)2 MoO2Cl4 pink[17]
MoCl4(Et2O)2 MoO2Cl4 beige[18]
MoCl3(thf)3 MoO3Cl3 red[17]
WCl4(Et2O)2 WO2Cl4 yellow[19]
MnCl3(thf)3 MnO3Cl3 brown-purple[20]
TcCl4(thf)2 TcO2Cl4 yellow[13]
ReCl4(thf)2 ReO2Cl4 green[21]
Fe4Cl8(thf)6 FeO2Cl3, FeO2Cl4 brown[22]
FeCl3(thf)2 FeO2Cl3[23] the related diethyl ether complex is brown
FeCl3(OEt2)2 FeO2Cl3 brown[11]
Co4Cl8(thf)6 CoO2Cl3, CoO2Cl4 blue[24]
[CoCl2(dme)]2 CoO2Cl3[25]
NiCl2(dimethoxyethane)2 NiCl2O4 yellow[26]
[Cu2Cl4(thf)3]n CuO2Cl4, CuOCl4 orange[27]
ZnCl2(thf)2 ZnO2Cl2 white[16]

Metal carbonyl complexes

  • M(CO)5(thf) (M = Cr, Mo, W)[4]
  • Mo(CO)3(diglyme)

References

  1. Duraj, S. A.; Towns; Baker; Schupp, J. (1990). "Structure of cis-Tetrachlorobis(tetrahydrofuran)hafnium(IV)". Acta Crystallographica C46 (5): 890–2. doi:10.1107/S010827018901382X. 
  2. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8. 
  3. Duan, Zhiming; Zhang, Yan; Zhang, Bin; Zhu, Daoben (2009). "Crystal-to-Crystal Transformation from Antiferromagnetic Chains into a Ferromagnetic Diamondoid Framework". Journal of the American Chemical Society 131 (20): 6934–6935. doi:10.1021/ja902101x. PMID 19402661. 
  4. 4.0 4.1 Schubert, U.; Friedrich, P.; Orama, O. (1978). "Kristall- und molekülstruktur von pentacarbonyltetrahydrofuran-chrom(0)". Journal of Organometallic Chemistry 144 (2): 175–179. doi:10.1016/S0022-328X(00)84160-1. 
  5. Bianchi, Sabrina; Bortoluzzi, Marco; Castelvetro, Valter; Marchetti, Fabio; Pampaloni, Guido; Pinzino, Calogero; Zacchini, Stefano (2016). "The reactivity of tungsten hexachloride with tetrahydrofuran and 2-methoxyethanol". Polyhedron 117: 769–776. doi:10.1016/j.poly.2016.07.024. 
  6. Choukroun, Robert; Moumboko, Pierre; Chevalier, Sandrine; Etienne, Michel; Donnadieu, Bruno (1998). "Cationic Homoleptic Vanadium(II), (IV), and (V) Complexes Arising from Protonolysis of [V(NEt2)4]". Angewandte Chemie International Edition 37 (22): 3169–3172. doi:10.1002/(SICI)1521-3773(19981204)37:22<3169::AID-ANIE3169>3.0.CO;2-0. PMID 29711321. 
  7. Kong, Gapgoung; Harakas, George N.; Whittlesey, Bruce R. (1995). "An Unusual Transition Metal Cluster Containing a Seven Metal Atom Plane. Syntheses and Crystal Structures of [Mn][Mn7(THF)6(CO)12]2, Mn3(THF)2(CO)10, and [Mn(THF)6][Mn(CO)5]2". Journal of the American Chemical Society 117 (12): 3502–3509. doi:10.1021/ja00117a019. 
  8. Lichtenberg, Crispin; Adelhardt, Mario; Wörle, Michael; Büttner, Torsten; Meyer, Karsten; Grützmacher, Hansjörg (2015). "Mono- and Dinuclear Neutral and Cationic Iron(II) Compounds Supported by an Amidinato-diolefin Ligand: Characterization and Catalytic Application". Organometallics 34 (12): 3079–3089. doi:10.1021/acs.organomet.5b00395. 
  9. Schwab, Miriam M.; Himmel, Daniel; Kacprzak, Sylwia; Radtke, Valentin; Kratzert, Daniel; Yassine, Zeinab; Weis, Philippe; Weber, Stefan et al. (2018). "Reactivity of [Ni(cod)2][Al(ORF)4] towards Small Molecules and Elements". Zeitschrift für Anorganische und Allgemeine Chemie 644: 50–57. doi:10.1002/zaac.201700367. 
  10. Crochet, Aurélien; Fromm, Katharina M. (2010). "Polyether Adducts of d-Block Metal Compounds as Starting Materials for New Cluster Compounds". Zeitschrift für anorganische und allgemeine Chemie 636 (8): 1484–1496. doi:10.1002/zaac.201000022. http://doc.rero.ch/record/20544/files/fro_pad.pdf. 
  11. 11.0 11.1 Spandl, Johann; Kusserow, M.; Brüdgam, I. (2003). "Alkoxo-Verbindungen des dreiwertigen Eisen: Synthese und Charakterisierung von [Fe2(Ot Bu)6], [Fe2Cl2(Ot Bu)4], [Fe2Cl4(Ot Bu)2] und [N(n Bu)4]2[Fe6OCl6(OMe)12]". Zeitschrift für anorganische und allgemeine Chemie 629 (6): 968–974. doi:10.1002/zaac.200300008. 
  12. 12.0 12.1 12.2 12.3 12.4 12.5 Manzer, L. E. (1982). Tetrahydrofuran Complexes of Selected Early Transition Metals. Inorganic Syntheses. 21. pp. 135–140. doi:10.1002/9780470132524.ch31. 
  13. 13.0 13.1 Hagenbach, Adelheid; Yegen, Eda; Abram, Ulrich (2006). "Technetium Tetrachloride as a Precursor for Small Technetium(IV) Complexes". Inorganic Chemistry 45 (18): 7331–7338. doi:10.1021/ic060896u. PMID 16933935. 
  14. 14.0 14.1 Sobota, Piotr; Ejfler, Jolanta; Szafert, Sławomir; Szczegot, Krzysztof; Sawka-Dobrowolska, Wanda (1993). "New intermediates for the Synthesis of Olefin Polymerization Catalysts: The Complexes [M2(μ-Cl)2Cl4(THF)4] (M = Ti or V, THF = Tetrahydrofuran); Crystal Structures and Properties". Journal of the Chemical Society, Dalton Transactions (15): 2353–2357. doi:10.1039/dt9930002353. 
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  20. Nachtigall, Olaf; Pataki, Astrid; Molski, Matthias; Lentz, Dieter; Spandl, Johann (2015). "Solvates of Manganese Trichloride Revisited - Synthesis, Isolation, and Crystal Structure of MnCl3(THF)3". Zeitschrift für Anorganische und Allgemeine Chemie 641 (6): 1164–1168. doi:10.1002/zaac.201500106. 
  21. Swidersky, H.-W.; Pebler, J.; Dehnicke, K.; Fenske, D. (1990). "Technetium Tetrachloride as a Precursor for Small Technetium(IV) Complexes". Inorganic Chemistry 45 (18): 7331–8. doi:10.1021/ic060896u. PMID 16933935. 
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  23. L. V. Ivakina, N. R. Strel'tsova, V. K. Bel'skii, P. A. Storozhenko, B. M. Bulychev, A. B. Tarasov (1987). Zh.Obshch.Khim. (Russ.J.Gen.Chem.) 57: 1600. 
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