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Complexes of the potentially hexadentate ligand bis{3-[6-(2,2′-bipyridyl)]pyrazol-1-yl}hydroborate with representative s-, p-, d- and f-block metal ions: factors promoting formation of mononuclear or double-helical dinuclear complexes

JonáA McCleverty, JohnáC Jeffery, MichaeláD Ward, SamanthaáM Couchman, JamesáS Fleming

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URIhttp://purl.tuc.gr/dl/dias/47161A19-C7D7-4470-810C-299A39C16C30-
Identifierhttps://doi.org/10.1039/A707936B-
Languageen-
Extent7 pagesel
TitleComplexes of the potentially hexadentate ligand bis{3-[6-(2,2′-bipyridyl)]pyrazol-1-yl}hydroborate with representative s-, p-, d- and f-block metal ions: factors promoting formation of mononuclear or double-helical dinuclear complexesen
CreatorJonáA McClevertyen
CreatorMichaeláD Warden
CreatorJohnáC Jefferyen
CreatorMichaeláD Warden
CreatorSamanthaáM Couchmanen
CreatorJamesáS Flemingen
PublisherRoyal Society of Chemistryen
Content SummaryComplexes of the new potentially hexadentate ligand bis{3-[6-(2,2′-bipyridyl)]pyrazol-1-yl}hydroborate (L–), containing two terdentate chelating arms linked by a –BH2– spacer, were prepared and crystallographically characterised with K+, Cu2+, Gd3+ and Tl+ as representatives of the s-, d-, f- and p-block metals respectively. The crystal structure of the K+ complex revealed it to be the double-helical dinuclear [K2L2], in which each metal ion is six-co-ordinated by a terdentate arm from each of the two ligands; the two ligands are therefore bridging, and folded at the flexible –BH2– spacer group. The complex [Cu2L2][BF4]2 has a similar double-helical dinuclear cation with six-co-ordinate metal centres, but with a greater metal–metal separation because of the greater electrostatic repulsion between two dipositive metal ions compared to [K2L2]. The complex [GdL(NO3)2] in contrast is mononuclear with the ligand co-ordinated in a pseudo-equatorial manner, having a shallow helical twist to avoid steric interference between the terminal pyridyl groups. The two pseudo-axial bidentate nitrate ligands complete the ten-fold co-ordination. Formation of a (triple) helical complex between Gd3+ and L–, known with other bis-terdentate compartmental ligands, is thought to be disfavoured in this case because of the electrostatic repulsion between the two +3 metal centres that would occur given the relatively short metal–metal separations imposed by the ligand. In [TlL] the Tl+ ion, which is comparable in size and identical in charge to K+, has a preference for lower co-ordination numbers, which is reflected in the fact that not all of the ligand binding sites are co-ordinated and there are three relatively short M–N interactions and two long, weak ones.en
Type of ItemPeer-Reviewed Journal Publicationen
Type of ItemΔημοσίευση σε Περιοδικό με Κριτέςel
Licensehttp://creativecommons.org/licenses/by/4.0/en
Date of Item2015-09-25-
Date of Publication1998-
SubjectChemistry, Analytic--Mathematicsen
SubjectChemistry, Analytic--Measurementen
SubjectChemistry, Analytic--Statistical methodsen
Subjectchemometricsen
Subjectchemistry analytic mathematicsen
Subjectchemistry analytic measurementen
Subjectchemistry analytic statistical methodsen
Bibliographic CitationJ. Fleming, S.M. Couchman, J.C Jeffery, J.A McCleverty, M.D Ward , "Complexes of the potentially hexadentate ligand bis{3-[6-(2,2′-bipyridyl)]pyrazol-1-yl}hydroborate with representative s-, p-, d- and f-block metal ions: factors promoting formation of mononuclear or double-helical dinuclear complexes ",J. Chem. Soc., Dalton Trans., ,vol.4, pp.537-544,1998.doi:10.1039/A707936Ben

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