Lanthanide‐Based Complexes Containing a Chiral trans‐1,2‐Diaminocyclohexane (DACH) Backbone: Spectroscopic Properties and Potential Applications

Abstract

In this minireview, we give an overview on the use of the chiral molecule trans‐1,2‐diaminocyclohexane (DACH) in several fields of application. This chiral backbone is present in a variety of metal complexes which are employed in (enantioselective) catalysis, chiral discrimination, molecular recognition and supramolecular chemistry. Metal extraction and biochemical and pharmaceutical applications also use the DACH molecule. This contribution is particularly focused on the interesting chemical‐physical properties discussed so far in the literature concerning lanthanide‐based complexes containing chiral ligands characterized by the presence of DACH in the structure. In particular, the interconnection between luminescence (total and circularly polarized), structure and thermodynamics of Eu(III), Tb(III) and Sm(III) complexes will be discussed also in light of their use as optical or chiroptical probes for the sensing of important analytes dissolved in aprotic and protic polar solvents. Several complexes show potential interest in the solid state as phosphors for light emitting devices or for the detection of volatile organic compounds.

Enantioselective Cytotoxicity of Chiral Diphosphine Ruthenium(II) Complexes Against Cancer Cells

“…The solvent was completely evaporated and water (2 mL) was added to the residue. The obtained solid was filtered, washed with cold water ( 3 J HP = 15.0 Hz, 3 J HH = 7.4 Hz, 3H; CHCH 3 ), 0.98 (ddd, 2 J HH = 14.4 Hz, 3 J HH = 10.2 Hz, 4 J HP = 1.6 Hz, 1H; CH 2 Cys), 0.77 (dd, 3 J HP = 12.7 Hz, 3 J HH = 6.8 Hz, 3H; CHCH 3 ). 13 DFT calculations: Density functional theory (DFT) calculations have been performed to: i) determine the relative stability of [Ru(η 1 -OAc)(CO)((R,R)-Skewphos)(phen)] + isomers; ii) study the hydrolysis reactions of 2 R + and the reactions of its derivatives with cysteine; iii) energy stability of 2 R + complex with (S)-and (R)-cysteine.…”

“…As a matter of fact, the use of suitable chiral ligands has been demonstrated a valuable strategy for achieving highly stereoselective catalytic reactions. Recently, great effort has been devoted to the search of efficient chiral anticancer complexes, a well‐known example is oxaliplatin, bearing ( R , R )‐cyclohexane‐1,2‐diamine, which forms DNA adducts with a higher rate than its ( S , S )‐enantiomer [1–3] . Although ruthenium derivatives are considered promising candidates as chemotherapeutic agents in addition to the platinum ones, [4–5] only few examples of chiral ruthenium complexes have been investigated [6] .…”

“…Recently, great effort has been devoted to the search of efficient chiral anticancer complexes, a well-known example is oxaliplatin, bearing (R,R)-cyclohexane-1,2-diamine, which forms DNA adducts with a higher rate than its (S,S)-enantiomer. [1][2][3] Although ruthenium derivatives are considered promising candidates as chemotherapeutic agents in addition to the platinum ones, [4][5] only few examples of chiral ruthenium complexes have been investigated. [6] In 2006 Meggers and co-workers isolated the derivatives A and B (Figure 1), containing a bidentate staurosporine, which are inhibitors of the glycogen synthase kinase-3 (GSK-3) with 6 and 260-fold higher activity, compared to their enantiomers.…”

“…J HP = 15.1 Hz,3 J HH = 7.5 Hz, 3H; CHCH 3 ), 0.82 (dd,3 J HP = 13.0 Hz, HH = 6.8 Hz, 3H; CHCH 3 ) 13. C{ 1 H} NMR (100.6 MHz, CDCl 3 , 298 K): δ = 204.7 (dd, 2 J CP = 20.0 Hz, 2 J CP = 15.2 Hz; CO), 177.3 (d; 3 J CP = 2.5 Hz; COCH 3 ), 177.2 (s; COCH 3 ), 154.0-122.7 (m; aromatic carbon atoms), 37.2 (t, 2 J CP = 4.1 Hz; CH 2 ), 32.8 (d, 1 J CP = 30.4 Hz; PCH), 24.8 (s; COCH 3 ), 23.6 (d, 4 J CP = 4.3 Hz; COCH 3 ), 22.9 (dd, 1 J CP = 31.6, 3 J CP =…”

Synthesis of bright water-soluble circularly polarized luminescence emitters as potential sensors

“…9 We chose to introduce chirality through the readily available enantiopure trans -1,2-diaminocyclohexane. 10 Tetrasubstitution of ( S , S )-1,2-diaminocyclohexane with 6-(bromomethyl)methylpicolinate afforded the protected ligand, and hydrolysis of the esters under acidic conditions provided the desired ( S , S )- N , N , N ′, N ′-tetrakis[(6-carboxypyridin-2-yl)methyl]-1,2-diaminocyclohexane ligand ( S , S )-H 4 tpadac as its hexahydrochloride salt (Fig. 1).…”