Synthetic, structural, spectroscopic, and electrochemical studies of mixed sandwich Rh(III) and Ir(III) complexes involving Cp* and tridentate macrocycles

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• 作者：Grant ; Gregory J. ; Lee ; John P. ; Helm ; Monte L. ; VanDerveer ; Donald G. ; Pennington ; William T. ; et. al.
• 关键词：1 ; 4 ; 7-Trithiacyclononane ; Rhodium complexes ; Iridium complexes ; Mixed sandwich complexes ; Macrocyclic ligands ; Pentamethylcyclopentadienide complexes
• 刊名：Journal of Organometallic Chemistry
• 出版年：2005
• 期刊代码：64_0022328x
• 类别：ch
• 出版时间：January 28, 2005
• 卷：690
• 期：3
• 页码：629-639
• 文件大小：494 K

摘要

The syntheses, structures, spectroscopy, and electrochemistry for six Ir(III) and Rh(III) mixed sandwich mononuclear complexes involving tridentate macrocycles and pentamethylcyclopentadienide (Cp*) are reported. The complexes are readily prepared by direct ligand substitution reactions from the dichloro bridged binuclear complexes, [{M(Cp*)(Cl)₂}₂]. All complexes have the general formula [M(L)(Cp*)]X₂ (M=Ir(III) or Rh(III), L=macrocycle, Formula Not Shown or Cl^芒芒芒) and exhibit a distorted octahedral structure involving three donor atoms from the macrocycle and the facially coordinating carbocyclic Cp* ligand. The complex cations include: [Rh(芒芒⁵ -Cp*)(9S3)]²⁺ (1), [Rh(芒芒⁵-Cp*)(9N3)]²⁺ (2), [Rh(芒芒⁵-Cp*)(10S3)]²⁺ (3), [Ir(芒芒⁵-Cp*)(9S3)]²⁺ (4), [Ir(芒芒⁵-Cp*)(9N3)]²⁺ (5), and [Ir(芒芒⁵-Cp*)(10S3)]²⁺ (6), where 9S3=1,4,7-trithiacyclononane, 9N3=1,4,7-triazacyclononane, and 10S3=1,4,7-trithiacyclodecane. The structures for all six complexes are supported by ¹H and ¹³C{¹H} NMR spectroscopy, and five complexes are also characterized by single-crystal X-ray crystallography (complexes 1芒芒芒5). The ¹H NMR splittings between the two sets of methylene protons for both the Rh(III) and Ir(III) 9S3 complexes are much larger (0.4 vs. 0.2 ppm) compared to those in the two 9N3 complexes. Similarly, the ¹³C{¹H} NMR spectra in all four thioether complexes show that the ring carbons in the Cp* ligand are shifted by over 10 ppm downfield compared to the azacrown complexes. The electrochemistry of the complexes is surprisingly invariable and is dominated by a single irreversible metal-centered reduction near 芒芒芒1.2 V vs. Fc/Fc⁺.