Optically active transition metal complexes

Inverted Piano Stools: A Molecular Recognition Motif That Enforces 1:1 Cocrystallization of Two Diastereomers in the Same Single Crystal

“…Surprisingly, the {(h 5 -C 5 H 5 )Rh} complex 9 is also a halfsandwich complex that exhibits 1:1 diastereomer cocrystallization. [12] A short Rh···Rh distance of 5.49 within the pair and strong CÀH···O and CÀH···Cl hydrogen bonds (Table 2) originating from the cyclopentadienyl ring establish a molecular recognition motif very similar to that shown in Figure 2.…”

“…In almost all of the molecular pairs with p-cymene ligands, the isopropyl and methyl substituents of the cymene rings are on opposite sides, following inversion symmetry. Compound 1, on the [5] 3 [(h 6 -p-cymene)Ru((S)-1-phenylethyl-salicylaldiminate)Cl] [9] 4 [(h 6 -p-cymene)Ru((R)-1-hydroxybut-2-yl-salicylaldiminate)Cl] [10] 5 [(h 6 -p-cymene)Ru(2-(S)-2'-methoxy-1,1'-binaphthyl-salicylaldiminate)Cl] [11] 6 [(h 6 -p-cymene)Ru((S)-methyl valinate-salicylaldiminate)I] [5] 7 [(h 6 -p-cymene)Os((S)-1-phenylethyl-salicylaldiminate)Cl] [5] 8 [(h 6 -p-cymene)Ru((R)-1-hydroxybut-2-yl-pyrrolylaldiminate)Cl] [10] 9 [(h 5 -C 5 H 5 )Rh((S)-1-phenylethyl-salicylaldiminate)Cl] [12] 10 [(h 6 -C 6 H 6 )Ru((S)-alaninate)9-ethylguaninate] [13] 11 [(h 6 -p-cymene)Ru((S)-1-phenylethyl-4,6-di-tert-butyl-salicylaldiminate)Cl] [14] 12 [(h 6 -p-cymene)Ru((S)-1-phenylethyl-salicylaldiminate)(H 2 O)]-ClO 4 [15] 13 [(h 6 -p-mesitylene)Ru((S)-alaninate)]Cl [16] 14 [(h 6 -p-cymene)Ru(chiraphosO)Cl] [17] 15 [(h 5 -C 5 Me 5 )Ir((S)-prolinate)Cl] [18,19] 16 [20] 17 [(h 6 -C 6 Me 6 )Ru(k 2 -l-AlaGlyGlyOMe)Cl] [21] 18 [(h 6 -C 6 H 6 )Ru((S)-alaninate)Cl] [13] Angewandte Chemie other hand, differs by having the two isopropyl and two methyl groups on the same side. Furthermore, the isopropyl substituent is usually on the side of the oxygen substituent in the same molecule (and the halogen substituent in the opposite molecule), except for the iodo derivative 6 and molecule 2 of compound 1.…”

Crystallization‐Induced Asymmetric Transformation of Chiral‐at‐metal Ruthenium(II) Complexes Bearing Achiral Ligands

“…Recently, Brunner and co-workers reported a diastereoselective preparation of Ir and Rh chiral-at-metal complexes by crystallization-induced asymmetric transformation. [15] However, the optically active bidentate Schiff base ligand was present in the coordination sphere in order to control the stereoselective isomerization of the chiral metal center during the crystallization.…”

(η5‐Pentamethylcyclopentadienyl)iridium(III) Complexes with η2‐N,O andη2‐P,S Ligands

“…The resonances of the protons of the η 5 -C 5 Me 5 groups in the 1 H NMR spectrum of 4 appear, due to the coupling to the iridium-bound hydrido ligand, as a doublet of doublets (δ = 1.62 ppm, 4 J H,P = 2.0, 4 J H,H = 0.8 Hz, 15 H) and those of 5 as a doublet (δ = 1.57 ppm, 4 J H,P = 1.9 Hz, 15 H). The resonances of the hydrido ligand in 4 and of the methyl group in 5 are observed as doublets at high field at δ = -15.37 (d, 2 J H,P = 36.0 Hz, 1 H) and -0.22 ppm (d, 3 J H,P = 6.1 Hz, 3 H), respectively.…”

“…However, in general, the diastereoselectivity is low and, due to the configurational instability at the metal center, epimerization reactions occur in solution. [4] Pyridine-2-carboxylic acid is an analog to amino acids and is commercially available. Examples of η 2 -coordinated pyridine-2-carboxylato ligands (η 2 -N,O) applied in organoiridium chemistry are [Ir(η 5 3 , although they were structurally not characterized.…”