In:
European Journal of Inorganic Chemistry, Wiley, Vol. 2013, No. 8 ( 2013-03-11), p. 1336-1350
Abstract:
The preparation and characterization of 30‐membered hexaza‐dithiophenolate macrocycles H 2 L 4 –H 2 L 6 with different degrees and patterns of N ‐alkylation and their complexation properties towards cobalt are reported. Three dinuclear {[Co III 2 (L 4 )(µ‐OH)] 3+ ( 3 ), [Co III Co II (L 5 )(µ‐OH)] 2+ ( 4 ), [Co II 2 H 2 (L 6 )Cl 2 ] 2+ ( 5 )} and one mononuclear complex {[Co II (L 6 )] 2+ ( 6 )} were obtained, isolated as ClO 4 – or BPh 4 – salts, and characterized by CHN analysis, ESI mass spetrometry, IR, UV/Vis, and NMR spectroscopy, cyclic voltammetry, magnetic susceptibility measurements (for 4 – 6 ), and X‐ray crystallography ( 3 – 6 ). In contrast to parent N 6 S 2 macrocycles with diethylenetriamine linkers, which support only face‐sharing bioctahedral [Co 2 L(L′)] n + complexes (L′ = bridging coligand), the new macrocycles show greater structural diversity enabling the formation of triply bridged complexes with octahedral Co III,II N 3 S 2 O ( 3 , 4 ), non‐bridged dinuclear complexes with tetrahedral Co II N 2 SCl ( 5 ), and mononuclear complexes with square‐pyramidal Co II N 3 S 2 ( 6 ) coordination environments. The increasing stability of the Co II oxidation level across this series of complexes is a consequence of the increasing degree of N ‐alkylation coupled with a decreasing ligand‐field strength of the tertiary amine functions, as demonstrated by significant anodic shifts in the cyclic voltammograms of 3 and 4 . The effective magnetic moments of the Co II ions in 4 , 5 , and 6 (4.67–5.23 µ B ) are significantly higher than the expected spin‐only value of 3.87 µ B , indicative of an orbital contribution to the magnetic moment.
Type of Medium:
Online Resource
ISSN:
1434-1948
,
1099-0682
DOI:
10.1002/ejic.v2013.8
DOI:
10.1002/ejic.201201314
Language:
English
Publisher:
Wiley
Publication Date:
2013
detail.hit.zdb_id:
1475009-0
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