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Nickel(II) bis(acetylacetonate)

January 01, 1970

Nickel(II) bis(acetylacetonate) is a coordination complex with the formula [Ni(acac)2]3, where acac is the anion C5H7O2− derived from deprotonation of acetylacetone. It is a dark green paramagnetic solid that is soluble in organic solvents such as toluene. It reacts with water to give the blue-green diaquo complex Ni(acac)2(H2O)2.[1]

Nickel(II) bis(acetylacetonate)
Names
Other names
Ni(acac)2, nickel acac
Identifiers
  • 3264-82-2 Y
3D model (JSmol)
  • Interactive image
ChemSpider
  • 2005906
ECHA InfoCard 100.019.887
EC Number
  • 221-875-7
  • 5359853
UNII
  • 5I48R807JO
  • DTXSID80904370
  • InChI=1S/2C5H8O2.Ni/c2*1-4(6)3-5(2)7;/h2*3,6H,1-2H3;/b2*4-3-;
    Key: SHWZFQPXYGHRKT-FDGPNNRMSA-N
  • C/C(=C/C(=O)C)/O.C/C(=C/C(=O)C)/O.[Ni]
Properties
C30H42Ni3O12
Molar mass 770.734 g·mol−1
Appearance dark green
Density 1.455 g/cm3
Melting point 229.5 °C (445.1 °F; 502.6 K) (decomposes)
H2O
Hazards
GHS labelling:
Danger
H302, H317, H334, H350
P201, P202, P261, P264, P270, P272, P280, P281, P285, P301+P312, P302+P352, P304+P341, P308+P313, P321, P330, P333+P313, P342+P311, P363, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)

Structure and properties edit

Anhydrous nickel(II) acetylacetonate exists as molecules of Ni3(acac)6. The three nickel atoms are approximately collinear and each pair of them is bridged by two μ2 oxygen atoms. Each nickel atom has tetragonally distorted octahedral geometry, caused by the difference in the length of the Ni-O bonds between the bridging and non-bridging oxygens.[2] Ni3(acac)6 molecules are almost centrosymmetric, despite the non-centrosymmetric point group of the cis-Ni(acac)2 "monomers," which is uncommon.[3] The trimeric structure allows all nickel centers to achieve an octahedral coordination. The trimer is only formed if intramolecular sharing of oxygen centers between pairs of nickel centers occurs. The anhydrous complex has interesting magnetic properties. Down to about 80 K it exhibits normal paramagnetism with an effective magnetic moment of 3.2 μB, close to the spin-only moment expected of a d8 ion with two unpaired electrons. The effective moment rises to 4.1 μB at 4.3 K, due to ferromagnetic exchange interactions involving all three nickel ions.[4]

When bound to bulkier analogues of acetylacetonate ligand, steric hindrance favors formation of the mononickel derivatives. This behavior is observed for the derivative of 3-methylacetylacetonate.[5]

Dihydrate edit

 
Structure of Ni(acac)2(H2O)2.

As in the anhydrous form, the Ni(II) centres occupy octahedral coordination sites. The coordination sphere is provided by two bidentate acetylacetonate (acac) ligands and two aquo ligands. Ni(acac)2(H2O)2 exists as cis and trans isomers.[6] Trans isomers are also observed for Ni(acac)2(pyridine-N-oxide)2.[7] In the trans isomers, the axial Ni-O bonds are greater in length (2.1000Å) than the equatorial Ni-O bonds (2.0085 Å and 1.9961Å).[8]

 
Trans and cis isomers of [Ni(acac)2X2] where X is a coordinating molecule

Synthesis edit

Bis(2,4-pentanedionato)nickel(II) is prepared by treating nickel nitrate with acetylacetone in the presence of base. The product is the blue-green diaquo complex Ni(CH3COCHCOCH3)2(H2O)2.[9]

Ni(NO3)2 + 2 CH3COCH2COCH3 + 2 H2O + 2 NaOH → Ni(CH3COCHCOCH3)2(H2O)2 + 2 NaNO3

This complex can be dehydrated using a Dean–Stark trap by azeotropic distillation:[9]

3 Ni(CH3COCHCOCH3)2(H2O)2 → [Ni(CH3COCHCOCH3)2]3 + 6 H2O

Upon heating Ni(acac)2(H2O)2 at 170–210 °C under reduced pressure (0.2–0.4 mmHg), the anhydrous form sublimes and water is removed.[3]

Reactions edit

The anhydrous complex reacts with a range of Lewis bases to give monomeric adducts.[10] Illustrative is the reaction with tetramethylethylenediamine (tmeda):[11]

[Ni(CH3COCHCOCH3)2]3 + 3 tmeda → 3 Ni(CH3COCHCOCH3)2(tmeda)

Ni(acac)2(H2O)2 reacts quickly in high yield at a methine positions, producing diamides from isocyanates. Related reactions occur with diethyl azodicarboxylate and dimethyl acetylenedicarboxylate:

Ni(acac)2(H2O)2 + 2 PhNCO → Ni(O2C5Me2C(O)NHPh)2 + 2 H2O

Applications edit

The anhydrous complex is the precursor to nickel-based catalysts such as nickel bis(cyclooctadiene) and tetramethylethylenediamine(dimethyl)nickel(II).[12][11]

[Ni(acac)2]3 is a precursor for the deposition of a thin film of NiO on conductive glass substrates using sol-gel techniques.[10]

 
Use of "Ni(acac)2" as the precatalyst.[13]

See also edit

References edit

  1. ^ R. C. Mehrotra; R. Bohra; D. P. Gaur (1978). Metal β-Diketones and Allied Derivatives. Academic Press. ISBN 0124881505.
  2. ^ G. J. Bullen, R. Mason & P. Pauling (1961). "Octahedral Co-ordination of Nickel in Nickel(II) Bisacetylacetone". Nature. 189 (4761): 291–292. doi:10.1038/189291a0. S2CID 37394858.
  3. ^ a b G. J. Bullen, R. Mason & P. Pauling. (1965). "The crystal and Molecular Structure of Bis(acetylacetonato)nickel (II)". Inorganic Chemistry. 4 (4): 456–462. doi:10.1021/ic50026a005.
  4. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 1157. ISBN 978-0-08-037941-8.
  5. ^ 1. A. Döhring, R. Goddard, P. W. Jolly, C. Krüger, V. R. Polyakov, "Monomer-Trimer Isomerism in 3-Substituted Pentane-2,4-dione Derivatives of Nickel(II)", Inorg. Chemistry 1997, 36, 177–183. doi:10.1021/ic960441c
  6. ^ M. Kudrat-E-Zahan, Y. Nishida & H. Sakiyama (2010). "Identification of cis/trans isomers of bis(acetylacetonato)nickel(II) complexes in solution based on electronic spectra". Inorganica Chimica Acta. 363: 168–172. doi:10.1016/j.ica.2009.09.011.
  7. ^ B. N. Figgis; M. A. Hitchman (2000). "Ligand Field Theory and its Application". {{cite journal}}: Cite journal requires |journal= (help)
  8. ^ O. Metin, L. T. Yildirim & S. Ozkar (2007). "Synthesis, characterization and crystal structure of bis(acetylacetonato)dimethanolnickel(II)". Inorganic Chemistry. 10 (9): 1121–1123. doi:10.1016/j.inoche.2007.06.011.
  9. ^ a b Wielandt, J. W.; Ruckerbauer, D. (2010). Bis(1,5-cyclooctadiene)nickel(0). Inorganic Syntheses. Vol. 35. p. 120. doi:10.1002/9780470651568.ch6.
  10. ^ a b Paul A. Williams; Anthony C. Jones; Jamie F. Bickley; Alexander Steiner; Hywel O. Davies; Timothy J. Leedham; Susan A. Impey; Joanne Garcia; Stephen Allen; Aline Rougier; Alexandra Blyr (2001). "Synthesis and Crystal Structures of Dimethylaminoethanol Adducts of Ni(II) Acetate and Ni(II) Acetylacetonate. Precursors for the Sol–Gel Deposition of Electrochromic Nickel Oxide Thin Films". Journal of Materials Chemistry. 11 (9): 2329–2334. doi:10.1039/b103288g.
  11. ^ a b Kaschube, Wilfried; Pörschke, Klaus R.; Wilke, Günther (1988). "Tmeda-Nickel-Komplexe". Journal of Organometallic Chemistry. 355 (1–3): 525–532. doi:10.1016/0022-328X(88)89050-8.
  12. ^ Göttker-Schnetmann, Inigo; Mecking, Stefan (2020). "A Practical Synthesis of (tmeda)Ni(CH3)2, Isotopically Labeled (tmeda)Ni(13CH3)2, and Neutral Chelated-Nickel Methyl Complexes". Organometallics. 39 (18): 3433–3440. doi:10.1021/acs.organomet.0c00500. S2CID 224930545.
  13. ^ Shrestha, Ruja; Dorn, Stephanie C. M.; Weix, Daniel J. (2013-01-16). "Nickel-Catalyzed Reductive Conjugate Addition to Enones via Allylnickel Intermediates". Journal of the American Chemical Society. 135 (2): 751–762. doi:10.1021/ja309176h. PMC 3547151. PMID 23270480.

January 01, 1970
nickel, acetylacetonate, coordination, complex, with, formula, acac, where, acac, anion, c5h7o2, derived, from, deprotonation, acetylacetone, dark, green, paramagnetic, solid, that, soluble, organic, solvents, such, toluene, reacts, with, water, give, blue, gr. Nickel II bis acetylacetonate is a coordination complex with the formula Ni acac 2 3 where acac is the anion C5H7O2 derived from deprotonation of acetylacetone It is a dark green paramagnetic solid that is soluble in organic solvents such as toluene It reacts with water to give the blue green diaquo complex Ni acac 2 H2O 2 1 Nickel II bis acetylacetonate Names Other names Ni acac 2 nickel acac Identifiers CAS Number 3264 82 2 Y 3D model JSmol Interactive image ChemSpider 2005906 ECHA InfoCard 100 019 887 EC Number 221 875 7 PubChem CID 5359853 UNII 5I48R807JO CompTox Dashboard EPA DTXSID80904370 InChI InChI 1S 2C5H8O2 Ni c2 1 4 6 3 5 2 7 h2 3 6H 1 2H3 b2 4 3 Key SHWZFQPXYGHRKT FDGPNNRMSA N SMILES C C C C O C O C C C C O C O Ni Properties Chemical formula C 30H 42Ni 3O 12 Molar mass 770 734 g mol 1 Appearance dark green Density 1 455 g cm3 Melting point 229 5 C 445 1 F 502 6 K decomposes Solubility in water H2O Hazards GHS labelling Pictograms Signal word Danger Hazard statements H302 H317 H334 H350 Precautionary statements P201 P202 P261 P264 P270 P272 P280 P281 P285 P301 P312 P302 P352 P304 P341 P308 P313 P321 P330 P333 P313 P342 P311 P363 P405 P501 Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Contents 1 Structure and properties 1 1 Dihydrate 2 Synthesis 3 Reactions 4 Applications 5 See also 6 ReferencesStructure and properties editAnhydrous nickel II acetylacetonate exists as molecules of Ni3 acac 6 The three nickel atoms are approximately collinear and each pair of them is bridged by two m2 oxygen atoms Each nickel atom has tetragonally distorted octahedral geometry caused by the difference in the length of the Ni O bonds between the bridging and non bridging oxygens 2 Ni3 acac 6 molecules are almost centrosymmetric despite the non centrosymmetric point group of the cis Ni acac 2 monomers which is uncommon 3 The trimeric structure allows all nickel centers to achieve an octahedral coordination The trimer is only formed if intramolecular sharing of oxygen centers between pairs of nickel centers occurs The anhydrous complex has interesting magnetic properties Down to about 80 K it exhibits normal paramagnetism with an effective magnetic moment of 3 2 mB close to the spin only moment expected of a d8 ion with two unpaired electrons The effective moment rises to 4 1 mB at 4 3 K due to ferromagnetic exchange interactions involving all three nickel ions 4 When bound to bulkier analogues of acetylacetonate ligand steric hindrance favors formation of the mononickel derivatives This behavior is observed for the derivative of 3 methylacetylacetonate 5 Dihydrate edit nbsp Structure of Ni acac 2 H2O 2 As in the anhydrous form the Ni II centres occupy octahedral coordination sites The coordination sphere is provided by two bidentate acetylacetonate acac ligands and two aquo ligands Ni acac 2 H2O 2 exists as cis and trans isomers 6 Trans isomers are also observed for Ni acac 2 pyridine N oxide 2 7 In the trans isomers the axial Ni O bonds are greater in length 2 1000A than the equatorial Ni O bonds 2 0085 A and 1 9961A 8 nbsp Trans and cis isomers of Ni acac 2X2 where X is a coordinating moleculeSynthesis editBis 2 4 pentanedionato nickel II is prepared by treating nickel nitrate with acetylacetone in the presence of base The product is the blue green diaquo complex Ni CH3COCHCOCH3 2 H2O 2 9 Ni NO3 2 2 CH3COCH2COCH3 2 H2O 2 NaOH Ni CH3COCHCOCH3 2 H2O 2 2 NaNO3 This complex can be dehydrated using a Dean Stark trap by azeotropic distillation 9 3 Ni CH3COCHCOCH3 2 H2O 2 Ni CH3COCHCOCH3 2 3 6 H2O Upon heating Ni acac 2 H2O 2 at 170 210 C under reduced pressure 0 2 0 4 mmHg the anhydrous form sublimes and water is removed 3 Reactions editThe anhydrous complex reacts with a range of Lewis bases to give monomeric adducts 10 Illustrative is the reaction with tetramethylethylenediamine tmeda 11 Ni CH3COCHCOCH3 2 3 3 tmeda 3 Ni CH3COCHCOCH3 2 tmeda Ni acac 2 H2O 2 reacts quickly in high yield at a methine positions producing diamides from isocyanates Related reactions occur with diethyl azodicarboxylate and dimethyl acetylenedicarboxylate Ni acac 2 H2O 2 2 PhNCO Ni O2C5Me2C O NHPh 2 2 H2OApplications editThe anhydrous complex is the precursor to nickel based catalysts such as nickel bis cyclooctadiene and tetramethylethylenediamine dimethyl nickel II 12 11 Ni acac 2 3 is a precursor for the deposition of a thin film of NiO on conductive glass substrates using sol gel techniques 10 nbsp Use of Ni acac 2 as the precatalyst 13 See also editPalladium II bis acetylacetonate Platinum II bis acetylacetonate References edit R C Mehrotra R Bohra D P Gaur 1978 Metal b Diketones and Allied Derivatives Academic Press ISBN 0124881505 G J Bullen R Mason amp P Pauling 1961 Octahedral Co ordination of Nickel in Nickel II Bisacetylacetone Nature 189 4761 291 292 doi 10 1038 189291a0 S2CID 37394858 a b G J Bullen R Mason amp P Pauling 1965 The crystal and Molecular Structure of Bis acetylacetonato nickel II Inorganic Chemistry 4 4 456 462 doi 10 1021 ic50026a005 Greenwood Norman N Earnshaw Alan 1997 Chemistry of the Elements 2nd ed Butterworth Heinemann p 1157 ISBN 978 0 08 037941 8 1 A Dohring R Goddard P W Jolly C Kruger V R Polyakov Monomer Trimer Isomerism in 3 Substituted Pentane 2 4 dione Derivatives of Nickel II Inorg Chemistry 1997 36 177 183 doi 10 1021 ic960441c M Kudrat E Zahan Y Nishida amp H Sakiyama 2010 Identification of cis trans isomers of bis acetylacetonato nickel II complexes in solution based on electronic spectra Inorganica Chimica Acta 363 168 172 doi 10 1016 j ica 2009 09 011 B N Figgis M A Hitchman 2000 Ligand Field Theory and its Application a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help O Metin L T Yildirim amp S Ozkar 2007 Synthesis characterization and crystal structure of bis acetylacetonato dimethanolnickel II Inorganic Chemistry 10 9 1121 1123 doi 10 1016 j inoche 2007 06 011 a b Wielandt J W Ruckerbauer D 2010 Bis 1 5 cyclooctadiene nickel 0 Inorganic Syntheses Vol 35 p 120 doi 10 1002 9780470651568 ch6 a b Paul A Williams Anthony C Jones Jamie F Bickley Alexander Steiner Hywel O Davies Timothy J Leedham Susan A Impey Joanne Garcia Stephen Allen Aline Rougier Alexandra Blyr 2001 Synthesis and Crystal Structures of Dimethylaminoethanol Adducts of Ni II Acetate and Ni II Acetylacetonate Precursors for the Sol Gel Deposition of Electrochromic Nickel Oxide Thin Films Journal of Materials Chemistry 11 9 2329 2334 doi 10 1039 b103288g a b Kaschube Wilfried Porschke Klaus R Wilke Gunther 1988 Tmeda Nickel Komplexe Journal of Organometallic Chemistry 355 1 3 525 532 doi 10 1016 0022 328X 88 89050 8 Gottker Schnetmann Inigo Mecking Stefan 2020 A Practical Synthesis of tmeda Ni CH3 2 Isotopically Labeled tmeda Ni 13CH3 2 and Neutral Chelated Nickel Methyl Complexes Organometallics 39 18 3433 3440 doi 10 1021 acs organomet 0c00500 S2CID 224930545 Shrestha Ruja Dorn Stephanie C M Weix Daniel J 2013 01 16 Nickel Catalyzed Reductive Conjugate Addition to Enones via Allylnickel Intermediates Journal of the American Chemical Society 135 2 751 762 doi 10 1021 ja309176h PMC 3547151 PMID 23270480 Retrieved from https en wikipedia org w index php title Nickel II bis acetylacetonate amp oldid 1213189268, wikipedia, wiki, book, books, library,

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