Disulfoxide Ligand Research Articles

Aqueous chemistry of ruthenium(II) complexes containing dimethylsulfoxide, and a chelated disulfoxide ligand or a cyclotetrathia ligand

The aqueous chemistry, including some kinetic studies, of our recently reported [RuII/IIICl(BPSP)]2(μ-Cl)3 (complex 1), where BPSP = 1,2-bis(propylsulfinyl)ethane, and a new complex cis-RuCl2(DMSO)(DMSO)(BESE) (2), where BESE = 1,2-bis(ethylsulfinyl)ethane, is described; both 1 and 2 are fully characterized. Such data are of importance for in vitro studies on cytotoxicity, accumulation and DNA-binding properties in selected cells, findings that will be published elsewhere. Discussed also are the complexes [Ru(12-ane-S4)(DMSO)(H2O)][OTf]2 (3), where 12-ane-S4 = 1,4,7,10-tetrathiacyclododecane, and cis-RuCl2(DMSO)L (4), where L = 3,6,9,14 tetrathiabicyclo-[9.2.1]-tetradeca-11,13-diene. Complexes 3 and 4 were first made by our group, but have been synthesized and studied subsequently by other groups; differences in findings are discussed.

Electronic and Steric Tuning of an Atropisomeric Disulfoxide Ligand Motif and Its Use in the Rh(I)-Catalyzed Addition Reactions of Boronic Acids to a Wide Range of Acceptors.

A novel chiral disulfoxide ligand pair bearing fluorine atoms at the 6 and 6' position of its atropisomeric backbone, ( M, S, S)- and ( P, S, S)- p-Tol-6F-BIPHESO, was synthesized. Complexation to a rhodium(I) precursor gave rise to μ-Cl- and μ-OH-bridged rhodium dimer complexes incorporating the new ( M, S, S)- p-Tol-6F-BIPHESO ligand, while its sibling ( P, S, S)- p-Tol-6F-BIPHESO was not complexed efficiently to the rhodium precursor. The performance of this disulfoxide ligand [( M, S, S)- p-Tol-6F-BIPHESO] in catalysis was tested in both 1,4- and 1,2-addition reactions of arylboronic acids. We show that addition to both cyclic and acyclic enones as well as N-tosylarylimines proceeds with high yields and high enantioselectivities to give the corresponding products. The synthesis of enantiomerically pure p-Tol-6F-BIPHESO is straightforward and inexpensive which, together with the high catalytic performance and wide substrate scope for these addition reactions, makes it a very attractive alternative to more classical chiral ligand entities.

A Bulky Disulfoxide Ligand for Pd-Catalyzed Oxidative Allylic C-H Amination with 2,2,2-Trichloroethyl Tosyl Carbamate.

Challenging substrates and conditions in homogeneous catalysis pose stringent demands on the ligands used. A novel, bulky, 1-adamantyl-substituted disulfoxide ligand designed after a systematic evaluation of the electronic and steric properties of disulfoxide substituents permits the allylic oxidative C-N coupling reaction to proceed at lower catalyst loading while requiring a smaller excess of reagents. Additionally, this ligand improves the yields when TsNHCOOCH2CCl3, a novel reagent that permits deprotection of the products under both acidic and basic conditions, is used.

ChemInform Abstract: A Chiral Disulfoxide Ligand for the Efficient Rhodium‐Catalyzed 1,2‐Addition of Arylboroxines to N‐Tosylarylimines.

Abstractaffording enantiomerically pure diarylmethylamines

Front Cover Picture: A Chiral Disulfoxide Ligand for the Efficient Rhodium-Catalyzed 1,2-Addition of Arylboroxines to N -Tosylarylimines (Adv. Synth. Catal. 11/2016)

Front Cover Picture: A Chiral Disulfoxide Ligand for the Efficient Rhodium-Catalyzed 1,2-Addition of Arylboroxines to <i>N</i> -Tosylarylimines (Adv. Synth. Catal. 11/2016)

A Chiral Disulfoxide Ligand for the 1,2-Addition of Arylboroxines to Imines

A Chiral Disulfoxide Ligand for the 1,2-Addition of Arylboroxines to Imines

A Chiral Disulfoxide Ligand for the Efficient Rhodium‐Catalyzed 1,2‐Addition of Arylboroxines to N‐Tosylarylimines

AbstractEnantiomerically pure diarylmethylamines are important building blocks in active pharmaceutical ingredients. Herein, we report a rhodium precatalyst with a chiral disulfoxide ligand that effects the 1,2‐addition of arylboroxines to aromatic imines to give high yields and high enantioselectivities of these products. The present paper describes a system that is very simple, where the ease of synthesis of the chiral ligand is combined with low catalyst loadings and reaction conditions that do not need any additives or external base.magnified image

ChemInform Abstract: Chiral Heterodisulfoxide Ligands in Rhodium‐Catalyzed Asymmetric 1,4‐Addition of Arylboronic Acids to Chromenones.

A new family of benzene-based chiral heterodisulfoxide ligands L1-L5 was synthesized in a single step. These disulfoxide ligands were applied in the rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to chromenones. The addition of diverse arylboronic acids to chromenones proceeds smoothly in up to 70% yield with up to 95% ee.

Chiral Heterodisulfoxide Ligands in Rhodium‐Catalyzed Asymmetric 1,4‐Addition of Arylboronic Acids to Chromenones

AbstractA new family of benzene‐based chiral heterodisulfoxide ligands L1–L5 was synthesized in a single step. These disulfoxide ligands were applied in the rhodium‐catalyzed asymmetric 1,4‐addition of arylboronic acids to chromenones. The addition of diverse arylboronic acids to chromenones proceeds smoothly in up to 70 % yield with up to 95 % ee.

C2‐Symmetric Chiral Disulfoxide Ligands in Rhodium‐Catalyzed 1,4‐Addition: From Ligand Synthesis to the Enantioselection Pathway

A family of chiral C(2)-symmetric disulfoxide ligands possessing biaryl atropisomeric backbones has been synthesized by using the Andersen methodology. Complete characterization includes X-ray crystallographic studies of all ligands and some of their rhodium complexes. Their synthesis, optical purity, electronic properties, and catalytic behavior in the prototypical rhodium-catalyzed 1,4-addition of phenylboronic acid to 2-cyclohexen-1-one are presented through an in depth study of this ligand class. Density functional theory calculations on the step of the catalytic cycle that determines the enantioselectivity are presented and reinforce the first hypothetical explanations for the high levels of asymmetric induction observed.

Syntheses and structures of three disulfoxide uranyl complexes

Three disulfoxide uranyl complexes [UO2(DBSOB)(NO3)2] n (1), [UO2(DBM)2]2(DBSOB) (2), and [UO2(PMBP)2]2(DBSOB) (3) (DBSOB = 1,4-di(butylsulfinyl)butane, HDBM = dibenzoylmethane, HPMBP = 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone) were synthesized and characterized. The [UO2(NO3)2] groups are connected by bridging disulfoxide ligands DBSOB to form a 1-D zigzag chain in 1. Two [UO2(DBM)2] or [UO2(PMBP)2] groups are connected by a bridging DBSOB to form the dimeric structures of 2 or 3, respectively. Complexes 1, 2, and 3 are the first structurally characterized disulfoxide–actinide compounds. Thermal stabilities of 1, 2, and 3 were investigated.

ChemInform Abstract: Disulfoxide Ligands in Rhodium‐Catalyzed Asymmetric 1,4‐Addition: First Studies and Future Directions

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Disulfoxide Ligands in Rhodium Catalyzed Asymmetric 1,4-Addition: First Studies and Future Directions

Disulfoxides with atropisomeric backbones are introduced as readily available chiral ligands for the rhodium-catalyzed 1,4-addition of arylboronic acids to unsaturated carbonyl compounds. The ligands are obtained in pure form from either commercially available or easily synthesized starting materials. Precatalysts with general formula {(disulfoxide)RhCl}2 were prepared in high yield and were fully characterized. Preliminary results on the influence of steric and electronic modifications of the ligand structure and their impact on the catalytic behavior are presented.

Structural Diversity and Modulation of Coordination Architectures with Flexible Dithioether or Disulfoxide Ligands

AbstractMetal complexes of flexible dithioether and disulfoxide ligands are briefly reviewed, focusing on the structural investigations based on X‐ray crystallographic analyses. Recent investigations from our laboratory have produced compelling experimental evidence that flexible dithioether and disulfoxide ligands exhibit rich coordination chemistry towards metal ions and have great potential in constructing metal complexes with diverse structures. The design and synthesis of the ligands and their complexes are described. A wide variety of crystal structures of mononuclear, discrete multinuclear complexes and coordination polymers are classified by their assembling fashions, and the coordination modes of the two types of ligands are summarized. Series of structurally related ligands with varied spacer lengths or terminal groups were systematically used to coordinate the same metal ion in similar reaction conditions to afford complexes with different structures, indicating that the spacer lengths and terminal groups of ligands have important effects on the structures of the complexes. Using the same ligand to coordinate with different metal ions gave distinct complexes, showing the influences of the affinity and geometry of metal ions on the structures of the complexes. In addition, varying the anions, the solvent used, and the ratio of reactants in synthesis also led to the formation of complexes with different structures. These results present a feasible way to control the structures of complexes with these or other ditopic flexible ligands by modifying the ligands, selecting metal ions, as well as adjusting reaction conditions, which has been regarded as a long‐time challenge in engineering metal–organic coordination architectures. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2008)

Structural Diversity and Modulation of Coordination Architectures with Flexible Dithioether or Disulfoxide Ligands (Eur. J. Inorg. Chem. 1/2008)

AbstractThe cover picture shows the complex constructions of flexible dithioether and disulfoxide ligands and the structural diversity of these complexes. Recent investigations from our and other laboratories have given compelling experimental evidence that flexible dithioether and disulfoxide ligands exhibit rich coordination chemistry towards metal ions and have great potential in constructing metal complexes with various interesting structures. Such results are reviewed, with the attempt to elucidate: (1) the coordination chemistry of the two types of ligands, (2) the structural diversities of these complexes, (3) structural modulation by finely modifying the ligands, selecting metal ions, and controlling other factors such as the solvents, reagent ratios, counterions. Details are presented in the Microreview by J.‐R. Li and X.‐H. Bu on p. 27 ff.

Dinuclear Eu(III), Gd(III), and Tb(III) Complexes of meso-1,2-Bis(ethylsulfinyl)ethane with 2,2′:62,2′′-Terpyridine as Co-ligand

Three dinuclear lanthanide complexes of flexible disulfoxide ligand meso-1,2-bis(ethylsulfinyl)ethane (L), [Ln2(L)2(μ-L)(tpy)4](ClO4)6(CHCl3)4 (Ln = Eu 1, Gd 2) and [Tb2(L)4(μ-L)(tpy)2](ClO4)6(CHCl3) 3 with 2,2′:6′,2′′-terpyridine (tpy) as co-ligand were synthesized and structurally characterized. In 1 and 2, the metal centre is nine-coordinated to two tpy and one-and-a-half L ligands, whereas in 3 it coordinates with one tpy and two-and-a-half L, which may be attributed to the influence of the lanthanide contraction. In such complexes the disulfoxide ligands perform two kinds of coordination modes, bridging and chelating, indicating their flexibility in the formation of such complexes.

Synthesis and crystal structure of a 1D disulfoxide-lanthanide(III) complex {[La(L)2(DMF)4](ClO4)3} n [L = 1,6-bis(ethylsulfinyl)hexane

A new disulfoxide-La(III) complex {[La(L)2(DMF)4](ClO4)3} n (1) has been prepared by the reaction of La(ClO4)3 · nH2O and a flexible disulfoxide ligand, 1,6-bis(ethylsulfinyl)hexane (L), and characterized by elemental analysis, IR and single-crystal X-ray diffraction analysis (monoclinic system, space group C2/c, with a = 24.94(2), b = 12.012(8), c = 20.81(1) Å, β = 117.57(1)°, V = 5527(6) Å3 and Z = 4). The crystal structure consists of polymeric chains of {[La(L)2(DMF)4]3+} n cations and anions. In the cation of 1, each La(III) center is coordinated to eight O atoms from four distinct L ligands and four DMF molecules to give a square antiprism coordination geometry. The adjacent two La(III) ions are linked by two L ligands, which adopt bis-monodentate O-coordination bridging mode to form a double-bridging zigzag chain containing 22-membered macrocycles.

Flexible Disulfoxides as Bridging Ligands for Copper(II) Coordination Architectures: Fine Tuning the Complex Structures by Ligand Modifications

Ten disulfoxide−CuII coordination architectures, {[Cu(meso-Lb1)2(ClO4)](ClO4)}n (1B), [Cu(meso-Lb2)2(ClO4)2]n (2B), [Cu(rac-Lb3)2(ClO4)2]n (3B), {[Cu(meso-Lb3)3](ClO4)2}n (3B‘), [Cu(meso-Lc1)2(ClO4)2]n (1C), [Cu(meso-Lc2)2(ClO4)]2(ClO4)2(CHCl3)2 (2C), {[Cu(meso-Lc3)2(ClO4)](ClO4)}n (3C), [Cu(meso-Ld1)2(ClO4)2]n (1D), {[Cu2(rac-Ld2)4(ClO4)2](ClO4)2(CHCl3)}n (2D), and [Cu(rac-Ld3)2(ClO4)2]n (3D), were obtained by the reaction of Cu(ClO4)2 with nine structurally related flexible disulfoxide ligands, RS(O)(CH2)nS(O)R (n = 2−4; R = −CH2CH3, −CH2CH2CH3, −CH2CH2CH2CH3 for Lbn-1, Lcn-1, and Ldn-1, respectively) in the presence of dehydrating reagent (diethoxyethane) in acetone/chloroform. The X-ray crystal structural analyses of the complexes revealed that all of them display a 2-D network structure, except for 2B and 2C, which display a one-dimensional and a dinuclear cage structure, respectively. All 2-D systems have a (4,4) topological arrangement with different conformations, except for 3B‘, which has a (3,6) structure. It is noteworthy that complexes 3B and 3B‘, with different structures, are obtained in the same reaction system, being a relatively rare case. In all of the complexes the ligands react in the bis-monodentate coordination mode, acting as linkage bridges: this feature is important for the assembly of the polymeric complexes. In addition, the configuration inversion of some disulfoxide ligands has been observed when reacting with CuII ions. In combination with other reported disulfoxide−CuII complexes, a systematic structural comparison was performed so as to summarize some general relationships among the spacer lengths, terminal groups of related ligands, and structures of the complexes. The magnetic behavior of three complexes, 1B−3B, as examples, was investigated.

Lanthanide Complexes of Disulfoxide Ligands with Varied Configurations: Influence of Lanthanide Contraction on the Structures of the Complexes

AbstractFour new disulfoxide‐LnIII complexes, [Ln(L)2(NO3)3]n {Ln = La (1), n = n; Ln = Gd (2), Dy (3) and Yb (4), n = 2}, have been prepared by the reaction of Ln(NO3)3·nH2O with meso‐1,3‐bis(ethylsulfinyl)propane (meso‐L) in methanol/triethylorthoformate, and their solid‐state structures were characterized by IR spectroscopy, elemental analyses and X‐ray diffraction. Complex 1 is a 1D double‐bridged chain in which the LaIII ions are ten‐coordinate and the L ligands adopt both meso and rac configurations, and a bis‐monodentate bridging coordination mode. While complexes 2–4 have isostructural dinuclear structures, in which the LnIII ions are nine‐coordinate and the ligands show two types of coordination fashions and configurations: bis‐monodentate bridging with a meso‐configuration, and monodentate coordination with a rac‐configuration. The structural differences between 1 and 2–4 indicate the influence of lanthanide contraction on the complex structures. In addition, a change in configuration of the ligand occurs when it reacts with metal ions. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2005)

A unique tetra-nuclear Ag I–disulfoxide complex, {[Ag 2(O,O-L)( μ-O- μ-(SO)-L) 2(ClO 4)]ClO 4} 2 (L= meso−1,2-bis(ethylsulfinyl)ethane) with unprecedented ligand coordination mode

The self-assembly of a flexible disulfoxide ligand, meso-1,2-bis(ethylsulfinyl)ethane ( L) with AgClO 4 led to the formation of a novel tetra-nuclear complex, {[Ag 2(O,O- L)( μ-O- μ-(SO)- L) 2(ClO 4)]ClO 4} 2, in which the Ag I ions exhibit two kinds of coordination modes: trigonal–bipyramidal and octahedral, and the ligands take bidentate (O,O) chelating and tridentate μ-O- μ-(SO) bridging-chelating coordination modes. Such a ligand coordination mode is unprecedented in the metal-complexes of disulfoxides.