Repozytorium

Complexes of heteroscorpionate trispyrazolylborate ligands. Part VI. Carboxylate induced conversion of mono-ligand Tp´M(L) into bis-ligand Tp´2M complexes (M=Co(II) and Cu(II)).

Autorzy

Tomasz Ruman

Zbigniew Ciunik

E. Szklanny

Stanisław Wołowiec

Rok wydania

2002

Czasopismo

Polyhedron

Numer woluminu

21

Strony

2743-2753

DOI

10.1016/S0277-5387(02)01286-X

Kolekcja

Naukowa

Język

Angielski

Typ publikacji

Artykuł

Streszczenie

A series of homoleptic complexes of hexacoordinate cobalt(II) and copper(II) complexes with 3,5-disubstituted homo- and heteroscorpionate tris(pyrazolyl)borate anionic ligands (Tp′) were synthesized, i.e. bis[hydrotris(3-phenyl,5-methylpyrazol-1-yl)borato]cobalt(II), bis[hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3-methyl,5-phenylpyrazol-1-yl)borato]cobalt(II) and bis[hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3-methyl,5-phenylpyrazol-1-yl)borato]copper(II) and their structures were elucidated crystallographically. The complexes were also formed spontaneously during attempted metathesis of the corresponding Tp′M(NCS) complexes into Tp′M(OOCCH(OH)CH3) complexes. In the case of the analogous conversion applied for the thiocyanato [hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3,5-dimethylpyrazol-1-yl)boratocobalt(II) complex with sodium carboxylates (lactate, pyruvate and 2-hydroxybutyrate), the cross-transfer of pyrazolyl residues between starting anionic ligands was observed resulting in formation of bis-ligand homo- and heteroleptic Tp′CoTp″ complexes, where Tp′, Tp″ were tris(pyrazolyl)borates composed of n 3(5)-phenyl,5(3)-methylpyrazolyl and (3−n) 3,5-dimethylpyrazolyl residues (n=0–3) identified by mass spectrometry. Metathesis of thiocyanate in thiocyanato hydrotris(3-phenyl,5-methylpyrazol-1-yl)boratocobalt(II) into pyruvate led to the isolation of stable the pyruvato hydrotris(3-phenyl,5-methylpyrazol-1-yl)boratocobalt(II) complex, the structure of which was determined crystallographically. The Tp′ ligands are η3 coordinated to metal ions in every case, whereas the pyruvate anion is coordinated through carboxylate and carbonyl oxygen atoms to the cobalt center. Two rotational isomers distinguishable by 1H NMR spectroscopy for the hexacoordinate bis[hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3-methyl,5-phenylpyrazol-1-yl)borato]cobalt(II) complex were detected in solution.Anionic hydrotris(3-phenyl,5-methylpyrazol-1-yl)borate and hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3-methyl,5-phenylpyrazol-1-yl)borate ligands (Tp′) form stable homoleptic bis-ligand complexes Tp′2M. They are also formed by dismutation of Tp′M(carboxylate) except in the case of stable pyruvato hydrotris(3-phenyl,5-methylpyrazol-1-yl)boratocobalt(II), for which the molecular structure was determined crystallographically. The cross-transfer of the 3,5-dimethylpyrazolyl moiety between two hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3,5-dimethylpyrazol-1-yl)borate ligands occurs during metathesis of thiocyanato hydrobis(3-phenyl,5-methylpyrazol-1-yl)(3,5-dimethylpyrazol-1-yl)boratocobalt(II) into the carboxylate analogues accompanied with spontaneous formation of a series of heteroleptic Tp′CoTp″ complexes.

Słowa kluczowe

Poly(3-Rpyrazolyl)borate cobalt(II) complexes, Structures, NMR

Adres publiczny

https://doi.org/10.1016/S0277-5387(02)01286-X

Strona internetowa wydawcy

http://www.elsevier.com

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