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Synthesis and Characterization of Copper(II) Complexes of a 14‐Membered cis ‐N 2 S 2 Dibenzo Macrocycle and of Its Bis‐acetato and Bis(methylpyridyl) Derivatives
Author(s) -
Bentfeld Roland,
Ehlers Norbert,
Mattes Rainer
Publication year - 1995
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19951281211
Subject(s) - chemistry , thioether , crystallography , ligand (biochemistry) , octahedron , copper , bond length , crystal structure , cationic polymerization , stereochemistry , coordination geometry , molecular geometry , ring (chemistry) , square pyramidal molecular geometry , molecule , hydrogen bond , polymer chemistry , biochemistry , receptor , organic chemistry
Abstract The synthesis and characterization of seven copper coordination compounds with the 14‐membered macrocyclic cis ‐N 2 S 2 dibenzo ligand 6,7,13,14,15,16,17,18‐octahydrodibenzo[ e,m ]‐[1,4,8,11]dithiadiazacyclotetradecine (L 1 ) and its N,N' ‐bisacetato and ‐bis(methylpyridyl) functionalized derivatives H 2 L 2 and L 3 are described. The structures of five compounds were determined by single‐crystal X‐ray diffraction. The tetrahedrally distorted square‐planar coordination geometry of [CuL 1 ](ClO 4 ) 2 ( 1 ) changes upon reduction of copper to a severely distorted tetrahedral geometry in [CuL 1 ]Br · MeCN ( 2 ). The Cu–N bond lengths increase from 1.988(3) to 2.029(5) Å; the Cu–S bond lengths decrease from 2.293(1) to 2.255(2) Å. Copper(II) is hexacoordinated in [CuHL 2 ]HSO 4 · 2.5 H 2 O ( 5 ) and [CuHL 2 ]ClO 4 · H 2 O ( 6 ). Both compounds exhibit very similar overall structures in the cationic part. The macrocyclic ring of the ligand is folded along an N ⃜S axis, the octahedral geometry is strongly Jahn‐Teller distorted, with O and S donor atoms in the apical positions. Compound 5 contains one very short [2.271(3) Å] and one long [2.701(3) Å] Cu–S (thioether) bond. In [CuL 3 ](ClO 4 ) 2 · 2 H 2 O ( 7 ) one thioether group of the ligand L 3 remains uncoordinated. The coordination polyhedron is rather irregular: Cu–S 2.506(3) and Cu–N 1.960(7)–2.107(8) Å. The compounds were further characterized by electronic and EPR spectroscopy and by cyclic voltammetry. Some relationships to the structural and spectroscopic properties of “blue” copper proteins were found.