Complexes of heteroscorpionate trispyrazolylborate anionic ligands

Łukasiewicz, Marta; Ciunik, Zbigniew; Wołowiec, Stanisław

doi:10.1016/s0277-5387(00)00512-x

Cited by 20 publications

(9 citation statements)

References 21 publications

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“…The cobalt‐centered bite angle is 133.1°, which is much lower than those found in tetracoordinate Tp Ph2 Cu(CO) (145.5°)9 and pentacoordinate Tp Ph2 Fe(OOCC(O)Ph) (139.6°) 10. It is noteworthy that an increasing steric hindrance at C ‐5(pyrazole) in the order H < CH 3 < Ph causes a tightening of the bite angle from 142.0° [5‐H in Tp Ph Co(NCS)(pzH)],7 through 140.3° [5‐CH 3 in Tp PhMe Co(NCS)(THF)]4 to 133.1° [5‐Ph in Tp Ph2 Co(NO 3 )] in pentacoordinate Tp′Co(XY) complexes.…”

Section: Resultsmentioning

confidence: 90%

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Anionic Poly(pyrazolyl)borate Ligands Obtained from 3,5-Dimethylpyrazole and 3,5-Diphenylpyrazole and Their Cobalt(II) Complexes − X-ray Crystallographic and1H NMR Studies

Ruman

Ciunik

Mazurek

et al. 2002

Eur. J. Inorg. Chem.

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Synthesis of poly(pyrazolyl)borate anionic ligands composed of 3,5-dimethyl-and 3,5-diphenylpyrazoles and their bis(ligand) high-spin cobalt(II) complexes are described. The molecular structures of [dihydrobis(3,5-diphenylpyrazolyl)borato][hydrobis(3,5-dimethylpyrazolyl)(3,5-diphenylpyrazolyl)-borato]cobalt(II) and bis[dihydro(3,5-dimethylpyrazolyl)(3,5-diphenylpyrazolyl)borato]cobalt(II) complexes were established by X-ray crystallography. The cobalt center is hexacoordinate in the former with five Co−N 2 (pyrazolyl) bonds and

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Section: Resultsmentioning

confidence: 90%

“…For comparison we also synthesized potassium hydrotris(3,5‐diphenylpyrazolyl)borate KTp Ph2 by the standard procedure8 and Tp Ph2 Co(NCS) complex ( 1′ ) by addition of KTp Ph2 in THF to an excess of cobalt(II) thiocyanate, as described previously 7…”

Section: Methodsmentioning

confidence: 99%

Anionic Poly(pyrazolyl)borate Ligands Obtained from 3,5-Dimethylpyrazole and 3,5-Diphenylpyrazole and Their Cobalt(II) Complexes − X-ray Crystallographic and1H NMR Studies

Ruman

Ciunik

Mazurek

et al. 2002

Eur. J. Inorg. Chem.

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“…The presence of small‐ or medium‐sized substituents at positions 3 and 5 of pyrazole units renders the Tp x Co(X) complexes able to coordinate Tp as the X unit in all of the compounds studied. Previously, it has been noted that the presence of merely one sterically demanding 3‐ tert ‐butyl or 3,5‐di‐ tert ‐butylpyrazolyl residue precluded such a conversion 13,10…”

Section: Resultsmentioning

confidence: 99%

Synthesis, X‐ray Crystallographic and ¹H NMR Spectroscopic Structural Studies on Cobalt(II) Complexes of Homoscorpionate, Heteroscorpionates and Chiral Tris(pyrazolyl)borates Obtained from 5(3)‐Isopropyl‐3(5)‐phenylpyrazole and 3,5‐Dimethylpyrazole

2003

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Keywords: Boron / Chirality / Cobalt / N ligands / NMR spectroscopy Condensation of 5(3)-isopropyl-3(5)-phenylpyrazole with sodium borohydride led to a mixture of tris(pyrazolyl)borate ligands (Tp x ) − the homoscorpionate hydrotris(5-isopropyl-3-phenylpyrazolyl)borate and the heteroscorpionates hydro(3-isopropyl-5-phenylpyrazolyl)bis(5-isopropyl-3-phenylpyrazolyl)borate and hydrobis(3-isopropyl-5-phenylpyrazolyl)(5-isopropyl-3-phenylpyrazolyl)borate − that were converted into Tp x Co(NCS) complexes. The molecular structures of pentacoordinate[hydrotris(5-isopropyl-3-phenylpyrazolyl)-borato](tetrahydrofuran)(thiocyanato)cobalt(II) (1-THF) and [hydrobis(3-isopropyl-5-phenylpyrazolyl)(5-isopropyl-3-phenylpyrazolyl)borato](tetrahydrofuran)(thiocyanato)-cobalt(II) (3-THF) were elucidated crystallographically. Hydro(3,5-dimethylpyrazolyl)bis(5-isopropyl-3-phenylpyrazolyl)borate was also obtained by condensation of 2.1 equiv. of 5(3)-isopropyl-3(5)-phenylpyrazole and 0.9 equiv. of 3,5-dimethylpyrazole with sodium borohydride, and it was

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“…A similar albeit larger shift is observed in [Tp*M(CysEt)] (M = Co, Ni, CysEt = L-cysteine ethyl ester) where the difference is 48 nm. 28, 29 In addition to the above charge transfer bands there is also a d-d transition between 654 and 658 nm for 4-6. Once again comparable bands are observed in previously reported [Tp R Ni(dtc)] complexes.…”

Section: Introductionmentioning

confidence: 97%

Redox-active nickel and cobalt tris(pyrazolyl)borate dithiocarbamate complexes: air-stable Co(ii) dithiocarbamates

Harding

Dokmaisrijan

et al. 2011

Dalton Trans.

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A series of new cobalt(II) and nickel(II) tris(3,5-diphenylpyrazolyl)borate (Tp(Ph2)) dithiocarbamate complexes [Tp(Ph2)M(dtc)] (M = Co, dtc = S₂CNEt₂ 1, S₂CNBz₂ 2 and S₂CN(CH₂)₄ 3; M = Ni, dtc = S₂CNEt₂ 4, S₂CNBz₂ 5 and S₂CN(CH₂)₄ 6) have been prepared by the reaction of [Tp(Ph2)MBr] with Nadtc in CH₂Cl₂. IR spectroscopy indicates that the Tp(Ph2) ligand is κ³ coordinated while the dithiocarbamate ligand is κ² coordinated. ¹H NMR and UV-Vis spectroscopy are consistent with high spin, five-coordinate metal centres. X-ray crystallographic studies of 1, 3 and 6 confirm the κ³ coordination of the Tp(Ph2) ligand and reveal an intermediate five-coordinate geometry with an asymmetrically coordinated dithiocarbamate ligand. Electrochemical studies of 1-6 reveal a metal centred reversible one-electron oxidation to M(III). Attempted oxidation of [Tp(Ph2)Co(dtc)] with [FeCpCp(COMe)]BF₄ yields [Co(dtc)₃], Hpz(Ph2) and a further product which may be [Tp(Ph2)CoBp(Ph2)]. DFT calculations indicate that the low redox potentials in these complexes result from a strongly antibonding M-S σ* HOMO.

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Complexes of heteroscorpionate trispyrazolylborate anionic ligands

Cited by 20 publications

References 21 publications

Anionic Poly(pyrazolyl)borate Ligands Obtained from 3,5-Dimethylpyrazole and 3,5-Diphenylpyrazole and Their Cobalt(II) Complexes − X-ray Crystallographic and1H NMR Studies

Anionic Poly(pyrazolyl)borate Ligands Obtained from 3,5-Dimethylpyrazole and 3,5-Diphenylpyrazole and Their Cobalt(II) Complexes − X-ray Crystallographic and1H NMR Studies

Synthesis, X‐ray Crystallographic and ¹H NMR Spectroscopic Structural Studies on Cobalt(II) Complexes of Homoscorpionate, Heteroscorpionates and Chiral Tris(pyrazolyl)borates Obtained from 5(3)‐Isopropyl‐3(5)‐phenylpyrazole and 3,5‐Dimethylpyrazole

Redox-active nickel and cobalt tris(pyrazolyl)borate dithiocarbamate complexes: air-stable Co(ii) dithiocarbamates

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Complexes of heteroscorpionate trispyrazolylborate anionic ligands

Cited by 20 publications

References 21 publications

Anionic Poly(pyrazolyl)borate Ligands Obtained from 3,5-Dimethylpyrazole and 3,5-Diphenylpyrazole and Their Cobalt(II) Complexes − X-ray Crystallographic and1H NMR Studies

Anionic Poly(pyrazolyl)borate Ligands Obtained from 3,5-Dimethylpyrazole and 3,5-Diphenylpyrazole and Their Cobalt(II) Complexes − X-ray Crystallographic and1H NMR Studies

Synthesis, X‐ray Crystallographic and 1H NMR Spectroscopic Structural Studies on Cobalt(II) Complexes of Homoscorpionate, Heteroscorpionates and Chiral Tris(pyrazolyl)borates Obtained from 5(3)‐Isopropyl‐3(5)‐phenylpyrazole and 3,5‐Dimethylpyrazole

Redox-active nickel and cobalt tris(pyrazolyl)borate dithiocarbamate complexes: air-stable Co(ii) dithiocarbamates

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Synthesis, X‐ray Crystallographic and ¹H NMR Spectroscopic Structural Studies on Cobalt(II) Complexes of Homoscorpionate, Heteroscorpionates and Chiral Tris(pyrazolyl)borates Obtained from 5(3)‐Isopropyl‐3(5)‐phenylpyrazole and 3,5‐Dimethylpyrazole