Synthesis, Crystal Structure, and Magnetic Properties of a Ferromagnetically Coupled Difluoro-Bridged Dinuclear Chromium(III) Complex with a Substituted Tetrahydrosalen Derivative as Ligand
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- 作者：Ralf Sanzenbacher ; Arnd Bö ; ttcher ; Horst Elias ; Martina Hü ; ber ; Wolfgang Haase ; Jø ; rgen Glerup ; Thomas B. Jensen ; Markus Neuburger ; Margareta Zehnder ; Johan Springborg ; and Carl Erik Ol
- 刊名：Inorganic Chemistry
- 出版年：1996
- 出版时间：December 18, 1996
- 年：1996
- 卷：35
- 期：26
- 页码：7493 - 7499
- 全文大小：268K
- 年卷期：v.35,no.26(December 18, 1996)
- ISSN：1520-510X
文摘
A novel difluoro-bridged dinuclear chromium(III)complex has been synthesized by the reaction oftrans-[Cr(py)4F2]ClO4 in2-methoxyethanol with a substituted tetrahydrosalen derivativeL8 (L8 means the negativelychargedligand obtained by dissociation of two protons fromH2L8 =N,N'-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-1,2-ethanediamine). The crystal structure of[CrL8F]2·2C3H8O2has been determined. The crystal system is triclinic,and the lattice constants are a = 9.604(2) Å,b = 13.346(2) Å, c = 15.751(2) Å,
= 74.00(1)
, 
beta2.gif" BORDER=0 ALIGN="middle"> = 87.94(1),and 
= 70.55(1). Z = 1 and the volume ofthe unit cell is 1826.40(49) Å3. The space groupis 
1 (No. 2).The refinement of 456 variables includes 6279 of the 7631independent reflections. The final residual is4.08%.The centrosymmetric dinuclear molecule consists of two slightlydistorted octahedrally cis coordinated chromiumcenters bound together by two fluoride bridges. The Cr-F-Crangle is 100.90(4), and the Cr-F(bridge)distancesare 2.0172(8) and 1.9754(9) Å, and the Cr-Cr distance is3.0787(4) Å. The configuration of the dinuclearmoleculeis cis,cis-O,O'-
,
, where cis refers tothe position of the two oxygen donors and and refer to theconfigurationof the two N,O chelates of the tetradentate ligand L8 ateach of the two chromium(III) centers. The twochromium(III) centers in the complex are ferromagnetically coupled. Onbasis of measurements of the field-dependentmagnetization and the magnetic susceptibility, respectively, it hasbeen shown unambiguously that the groundstate is a septet state. It has not been possible to determine themonoatomic zero field splitting parameter Dfromthe magnetic susceptibility measurements, but the parameter has beendetermined from the EPR spectra measuredat 4 and 21 K. From simulation of the EPR spectra the followingparameters have been obtained: J = -1.4cm-1, De = 0.008cm-1, Ee = -0.015cm-1, Da =Db = -0.658 cm-1,Ea = Eb = 0.133cm-1, gxa= gxb =gya= gyb = 1.98, andgza =gzb = 2.00.
= 74.00(1), beta2.gif" BORDER=0 ALIGN="middle"> = 87.94(1),and = 70.55(1). Z = 1 and the volume ofthe unit cell is 1826.40(49) Å3. The space groupis 1 (No. 2).The refinement of 456 variables includes 6279 of the 7631independent reflections. The final residual is4.08%.The centrosymmetric dinuclear molecule consists of two slightlydistorted octahedrally cis coordinated chromiumcenters bound together by two fluoride bridges. The Cr-F-Crangle is 100.90(4), and the Cr-F(bridge)distancesare 2.0172(8) and 1.9754(9) Å, and the Cr-Cr distance is3.0787(4) Å. The configuration of the dinuclearmoleculeis cis,cis-O,O'-,, where cis refers tothe position of the two oxygen donors and and refer to theconfigurationof the two N,O chelates of the tetradentate ligand L8 ateach of the two chromium(III) centers. The twochromium(III) centers in the complex are ferromagnetically coupled. Onbasis of measurements of the field-dependentmagnetization and the magnetic susceptibility, respectively, it hasbeen shown unambiguously that the groundstate is a septet state. It has not been possible to determine themonoatomic zero field splitting parameter Dfromthe magnetic susceptibility measurements, but the parameter has beendetermined from the EPR spectra measuredat 4 and 21 K. From simulation of the EPR spectra the followingparameters have been obtained: J = -1.4cm-1, De = 0.008cm-1, Ee = -0.015cm-1, Da =Db = -0.658 cm-1,Ea = Eb = 0.133cm-1, gxa= gxb =gya= gyb = 1.98, andgza =gzb = 2.00.