Control of the Thermal and Photochemical Aquation of the Hexacyanochromate(III) and Aquapentacyanochromate(III) Ions by Formation of a Supramolecular Structure with [32]ane-N8
摘要:
The thermal aquation rate constant and the photoaquation quantum yield of [Cr(CN)(6)](3-) are reduced by a factor of 40 and 3, respectively, when the complex forms a 1:1 adduct with the protonated form of the polyaza macrocycle [32]ane-N-8. On the other hand, the same macrocycle has practically no effect on the photoaquation of [Cr(CN)(5)(H2O)](2-) and a very small effect on the thermal reaction of this complex. These results are discussed in relation to the thermal and photochemical reaction mechanisms and to the steric configuration of the adducts between complexes and macrocycle.
A novel example of an antiferromagnetically coupled CuIIMnIICrIII} heterotrispin chain with double phenoxido, single cyanido and oxalato as bridging ligands was obtained by a one-pot synthesis.
Exchange coupling across the cyanide bridge: structural and DFT interpretation of the magnetic properties of a binuclear chromium(<scp>iii</scp>) complex
作者:Pablo Alborés、Leonardo D. Slep、Thomas Weyhermüller、Eva Rentschler、Luis M. Baraldo
DOI:10.1039/b508386a
日期:——
water molecules present in the structure or with a NH group of the macrocycle of an adjacent molecule. From magnetic susceptibility measurements, the dimer was found to exhibit antiferromagnetic interaction between the Cr(III) centers with J = −16 cm−1 (Ĥ = −2JŜAŜB). Structural and magnetic parameters have been calculated by density functional theoretical methods at the B3LYP level. The exchange coupling
Hexacyanidometalate molecular chemistry, part III: di-, tri-, tetra-, hexa- and hepta-nuclear chromium–nickel complexes: Control of spin, structural anisotropy, intra- and inter-molecular exchange couplings
polynuclear complexes, [Cr(CN)n(CNNiL)6−n]m+, (with n = 0–5 and L = pentadentate ligand), were synthesised: CrNi, five CrNi2, CrNi3, CrNi5 and CrNi6. The compounds have been fully characterised by IR spectroscopy, mass spectrometry and X-ray crystallography. Their magnetic properties have been studied and the spin and the anisotropy values as well as the intra- and inter-molecular exchange couplings
摘要合成了九种由μ-氰基桥接的多核络合物[Cr(CN)n(CNNiL)6-n] m +(n = 0-5,L =五齿配体):CrNi,五个CrNi2,CrNi3,CrNi5和CrNi6。该化合物已经通过IR光谱,质谱和X射线晶体学进行了充分表征。已经研究了它们的磁性,并评估了自旋和各向异性值以及分子内和分子间交换耦合。自旋状态从5/2到15/2(铁磁相互作用)变化,有效各向异性因子从0到0.5 cm-1变化。实验中,μ-氰基桥联的自旋载体Cr(III)和Ni(II)之间的交换耦合随着C–N–Ni角的增加而在+4.5到+18.3 cm-1之间变化。通过计算研究,可以提出磁结构相关性,并通过氰基桥合理化Cr(III)(t 2 g 3)和Ni(II)(例如2)之间交换相互作用的最相关特征。为了减少分子间的相互作用,已经通过共结晶成功地将铬(III)-镍(II)化合物与等价的钴(III)-镍(II)进行了稀释。
Systematic Investigation of Trigonal-Bipyramidal Cyanide-Bridged Clusters of the First-Row Transition Metals
作者:Mikhail Shatruk、Kristen E. Chambers、Andrey V. Prosvirin、Kim R. Dunbar
DOI:10.1021/ic061856t
日期:2007.6.25
Reactions between [M'(III)(CN)(6)](3-) anions (M' = Co, Cr, or Fe) and mononuclear complexes of M(II) ions (M = Cr, Mn, Co, Ni, or Zn) produce a family of pentanuclear clusters [M(tmphen)(2)](3)[M'(CN)(6)](2)]}. The core of the clusters is formed by five metal ions that are bridged through six CN- linkers into a trigonal bipyramid, with M and M' ions occupying equatorial and axial positions of the