TY - JOUR
T1 - Trinuclear Cu(II) complexes containing peripheral ketonic oxygen bridges and a μ3-OH core
T2 - Steric influence on their structures and existence
AU - Sarkar, Biswarup
AU - Sinha Ray, Mau
AU - Drew, Michael G.B.
AU - Figuerola, Albert
AU - Diaz, Carmen
AU - Ghosh, Ashutosh
N1 - Funding Information:
This work was supported by CSIR, Government of India [Junior Research Fellowship to B.S., Sanction No. 9/28(620)/2003-EMR-I] and the Spanish Government (Grant BQU2003-00539). We also thank EPSRC and the University of Reading for funds for the Image Plate system.
PY - 2006/11/13
Y1 - 2006/11/13
N2 - Two tridentate Schiff bases, HL1(6-amino-3-methyl-1-phenyl-4-azahex-2-en-1-one), and HL2 (6-amino-3,6-dimethyl-1-phenyl-4-azahex-2-en-1-one) on reaction with Cu(II) perchlorate in the presence of triethyl amine yielded two new trinuclear copper(II) complexes, [(CuL1)3(μ3-OH)](ClO4) 2 (1) and [(CuL2)3(μ3-OH)](ClO4) 2 · 0.75H2O (2), whereas another tridentate ligand HL3 (7-amino-3-methyl-1-phenyl-4-azahept-2-en-1-one) underwent hydrolysis under the same reaction conditions to result in the formation of a mononuclear complex, [Cu(bn)(pn)ClO4] (3) [where bn = 1-benzoylacetonate and pn = 1,3-propanediamine]. All three complexes have been characterized by X-ray crystallography. For both 1 and 2 the cationic part is trinuclear with a [Cu3OH] core held by three carbonyl oxygen bridges between each pair of copper(II) atoms. The structure of 3 is a monomer with a chelating 1,3-propanediamine and a benzoyl acetone moiety. Magnetic measurements of 1 and 2 have been performed in the 2-300 K temperature range. The experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = -J(S1S2 + S2S3 + S1S3), yielding as best fit parameters: J = -25.6 cm-1, g = 2.21 for 1 and J = -11.2 cm-1, g = 2.10 for 2. The EPR spectra at low temperature could be indicative of spin frustration in complex 1.
AB - Two tridentate Schiff bases, HL1(6-amino-3-methyl-1-phenyl-4-azahex-2-en-1-one), and HL2 (6-amino-3,6-dimethyl-1-phenyl-4-azahex-2-en-1-one) on reaction with Cu(II) perchlorate in the presence of triethyl amine yielded two new trinuclear copper(II) complexes, [(CuL1)3(μ3-OH)](ClO4) 2 (1) and [(CuL2)3(μ3-OH)](ClO4) 2 · 0.75H2O (2), whereas another tridentate ligand HL3 (7-amino-3-methyl-1-phenyl-4-azahept-2-en-1-one) underwent hydrolysis under the same reaction conditions to result in the formation of a mononuclear complex, [Cu(bn)(pn)ClO4] (3) [where bn = 1-benzoylacetonate and pn = 1,3-propanediamine]. All three complexes have been characterized by X-ray crystallography. For both 1 and 2 the cationic part is trinuclear with a [Cu3OH] core held by three carbonyl oxygen bridges between each pair of copper(II) atoms. The structure of 3 is a monomer with a chelating 1,3-propanediamine and a benzoyl acetone moiety. Magnetic measurements of 1 and 2 have been performed in the 2-300 K temperature range. The experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = -J(S1S2 + S2S3 + S1S3), yielding as best fit parameters: J = -25.6 cm-1, g = 2.21 for 1 and J = -11.2 cm-1, g = 2.10 for 2. The EPR spectra at low temperature could be indicative of spin frustration in complex 1.
KW - Copper trimers
KW - Magnetic properties
KW - Schiff base
KW - X-ray structure
UR - http://www.scopus.com/inward/record.url?scp=33751060273&partnerID=8YFLogxK
U2 - 10.1016/j.poly.2006.05.032
DO - 10.1016/j.poly.2006.05.032
M3 - Article
AN - SCOPUS:33751060273
SN - 0277-5387
VL - 25
SP - 3084
EP - 3094
JO - Polyhedron
JF - Polyhedron
IS - 16
ER -