Preparation, Structures, and Redox and Emission Characteristics of the Isothiocyanate Complexes of Hexarhenium(III) Clusters [Re6(<img src="http://pubs.acs.org/images/entities/mgr.gif" bord
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- 作者：Takashi Yoshimura ; Zhong-Ning Chen ; Ai Itasaka ; Masaaki Abe ; Yoichi Sasaki ; Shoji Ishizaka ; Noboru Kitamura ; Spartak S. Yarovoi ; Sergey F. Solodovnikov ; and Vladimir E. Fedorov
- 刊名：Inorganic Chemistry
- 出版年：2003
- 出版时间：August 11, 2003
- 年：2003
- 卷：42
- 期：16
- 页码：4857 - 4863
- 全文大小：134K
- 年卷期：v.42,no.16(August 11, 2003)
- ISSN：1520-510X
文摘
Hexarhenium(III) complexes with terminal isothiocyanate ligands, {(n-C4H9)4N}4[Re6(<IMG SRC="/images/entities/mgr.gif">3-S)8(NCS)6] (1) and (L)4[Re6(
3-Se)8(NCS)6] (L+ = PPN+ (2a), (n-C4H9)4N+ (2b)), have been prepared by three different methods. Complex1 was prepared by the reaction of {(n-C4H9)4N}4[Re6(3-S)8Cl6] with molten KSCN at 200 
C, while 2b was obtainedby refluxing the chlorobenzene-DMF (2:1 v/v) solution of [Re6(3-Se)8(CH3CN)6](SbF6)2 and [(n-C4H9)4N]SCN. The[Re6(3-Se)8(NCS)6]4- anion was also obtained from a mixture of Cs2[Re6(3-Se)8Br4] and KSCN in C2H5OH by amechanochemical activation at room temperature for 20 h and isolated as 2a. The X-ray structures of 1 and2a·4DMF have been determined (1, C70H144N10S14Re6, monoclinic, space group P21/n (No. 14), a = 14.464(7) Å,b = 22.059(6) Å, c = 16.642(8) Å, 
= 113.62(3), V = 4864(3) Å3, Z = 2; 2a·4DMF, C162H144N14O4P8S6Se8Re6,triclinic, space group P
(No. 2), a = 15.263(2) Å, b = 16.429(2) Å, c = 17.111(3) Å, 
= 84.07(1), =84.95(1), 
= 74.21(1), V = 4098.3(8) Å3, Z = 1). All the NCS- ligands in both complexes are coordinated tothe metal center via nitrogen site with the Re-N distances in the range of 2.07-2.13 Å. The redox potentials ofthe reversible ReIII6/ReIII5ReIV process in acetonitrile are +0.84 and +0.70 V vs. Ag/AgCl for [Re6(3-S)8(NCS)6]4-and [Re6(3-Se)8(NCS)6]4-, respectively, which are the most positive among the known hexarhenium complexeswith six terminal anionic ligands. The complexes show strong red luminescence with the emission maxima (
max/nm), lifetimes (
em/s), and quantum yields (
em) being 745 and 715, 10.4 and 11.8, and 0.091 and 0.15 for 1 and2b, respectively, in acetonitrile. The data reasonably well fit in the energy-gap plots of other hexarhenium(III)complexes. The temperature dependence of the emission spectra and em of 1 and {(n-C4H9)4N}4[Re6(3-S)8Cl6]are also reported.
3-Se)8(NCS)6] (L+ = PPN+ (2a), (n-C4H9)4N+ (2b)), have been prepared by three different methods. Complex1 was prepared by the reaction of {(n-C4H9)4N}4[Re6(3-S)8Cl6] with molten KSCN at 200 C, while 2b was obtainedby refluxing the chlorobenzene-DMF (2:1 v/v) solution of [Re6(3-Se)8(CH3CN)6](SbF6)2 and [(n-C4H9)4N]SCN. The[Re6(3-Se)8(NCS)6]4- anion was also obtained from a mixture of Cs2[Re6(3-Se)8Br4] and KSCN in C2H5OH by amechanochemical activation at room temperature for 20 h and isolated as 2a. The X-ray structures of 1 and2a·4DMF have been determined (1, C70H144N10S14Re6, monoclinic, space group P21/n (No. 14), a = 14.464(7) Å,b = 22.059(6) Å, c = 16.642(8) Å, = 113.62(3), V = 4864(3) Å3, Z = 2; 2a·4DMF, C162H144N14O4P8S6Se8Re6,triclinic, space group P (No. 2), a = 15.263(2) Å, b = 16.429(2) Å, c = 17.111(3) Å, = 84.07(1), =84.95(1), = 74.21(1), V = 4098.3(8) Å3, Z = 1). All the NCS- ligands in both complexes are coordinated tothe metal center via nitrogen site with the Re-N distances in the range of 2.07-2.13 Å. The redox potentials ofthe reversible ReIII6/ReIII5ReIV process in acetonitrile are +0.84 and +0.70 V vs. Ag/AgCl for [Re6(3-S)8(NCS)6]4-and [Re6(3-Se)8(NCS)6]4-, respectively, which are the most positive among the known hexarhenium complexeswith six terminal anionic ligands. The complexes show strong red luminescence with the emission maxima (max/nm), lifetimes (em/s), and quantum yields (em) being 745 and 715, 10.4 and 11.8, and 0.091 and 0.15 for 1 and2b, respectively, in acetonitrile. The data reasonably well fit in the energy-gap plots of other hexarhenium(III)complexes. The temperature dependence of the emission spectra and em of 1 and {(n-C4H9)4N}4[Re6(3-S)8Cl6]are also reported.