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Comparison of thallium(I) complexes with mesityl‐substituted tris(pyrazolyl)hydroborate ligands, [Tl{HB(3‐Ms‐5‐Mepz) 3 }] and [Tl{HB(3‐Ms‐5‐Mepz) 2 (3‐Me‐5‐Mspz)}]
Author(s) -
Fujisawa Kiyoshi,
Shimizu Masaya,
Szilagyi Robert K.
Publication year - 2016
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229615023797
Subject(s) - chemistry , thallium , steric effects , dihedral angle , tris , metal , coordination number , crystallography , bond length , crystal structure , coordination complex , medicinal chemistry , chelation , methylene , molecule , stereochemistry , inorganic chemistry , organic chemistry , hydrogen bond , ion , biochemistry
Tris(pyrazolyl)borate (scorpionate) ligands can be considered as the most prolific ligands in contemporary coordination chemistry due to the availability of various steric and electronic substituents at the pyrazolyl rings that allow fine‐tuning of the open‐coordination site for metal centres. The thallium(I) complexes of anionic tridentate‐chelating scorpionate ligands, namely [tris(3‐mesityl‐5‐methyl‐1 H ‐pyrazol‐1‐yl‐κ N 2 )hydroborato]thallium(I) monohydrate, [Tl(C 39 H 46 BN 6 )]·H 2 O, (I), and [bis(3‐mesityl‐5‐methyl‐1 H ‐pyrazol‐1‐yl‐κ N 2 )(5‐mesityl‐3‐methyl‐1 H ‐pyrazol‐1‐yl‐κ N 2 )hydroborato]thallium(I), [Tl(C 39 H 46 BN 6 )], (II), show a {Tl I N 3 } coordination, with average Tl I —N bond lengths of 2.53 and 2.55 Å in (I) and (II), respectively. The overall Tl I coordination geometry is distorted trigonal pyramidal, with the average N—Tl I —N angle being approximately 73° for both. The dihedral angle between the planes of the pyrazolyl and benzene rings of the mesityl group is 82° in (I), while the corresponding angles in (II) are in the range 64–104°. The structural differences between the two ligands are expected to contribute to the different reactivities of the transition metal coordination complexes towards activation of small molecules such as dioxygen and ethylene.