Dithioether Ligands Research Articles

1,1,2,2-Tetramethyl-1,2-bis(phenylthiomethyl)disilane, a Flexible Ligand for the Construction of Macrocyclic, Mesocyclic, and Bridged Dithioether Complexes. Synthesis of the Bis-silylated OlefinsZ-(PhSCH2)Me2SiC(H)C(Ar)SiMe2(CH2SPh) by Catalytic Activation of the Si−Si Bond

The functionalized disilane (PhSCH2)Me2SiSiMe2(CH2SPh) (1) has been prepared and coordinated as a dithioether ligand on [PtCl2(PhCN)2] to afford the fluxional seven-membered chelate complex cis-[Pt...

Synthesis and crystal structure of a silver(I) complex with dithioether ligand

The reaction of the dithioether ligand, 2,3-bis(5-methyl-1,3,4-thiadiazole-2-thiomethyl) quinoxaline (L) with AgBF4, leads to the formation of a novel complex {[AgL](BF4)}∞ 1, which has been characterized by single-crystal X-ray diffraction analysis: monoclinic, space group C2/c, with a = 20.316(7) A, b = 12.401(4) A, c = 18.039(6) A, β = 108.404(6)° and V = 4312(3) A3. The crystal structure of the complex consists of 1D {[AgL]+}∞ cation chain and BF4 − anions. In 1, the coordination geometry of AgI center can be best described as trigonal planar coordinated by three N from two distinct L ligands. The ligand is polydentate with one end adopting a bidentate conformation to chelate an AgI atom and the other end monodentate to bridge another AgI resulting in an infinite chain along b axis. There exist Ag⋯N weak coordination, π–π stacking and F⋯S weak interactions in the complex, and these weak interactions link the 1D complex into 3D supramolecular structure and further stabilize the crystal structure in the solid state.

New Coordination Architectures of Dithioether Ligand with Silver Salts: Effect of Anions on Complex Structures

Reactions of a flexible dithioether ligand, 2,3-bis(5-methyl-1,3,4-thiadiazole-2-thiomethyl)quinoxaline (L), with AgX (X = ClO4ˉ or PF6ˉ) lead to the formation of two new one-dimensional (1D) silver(i) complexes: {[AgL](ClO4)}∞ 1 and {[Ag2L(CH3OH)](PF6)2(CH3OH)}∞ 2, which have been characterized by elemental analysis, IR spectroscopy, and X-ray crystallography. Although 1 and 2 are synthesized under the same conditions, they take different structures due to the difference in anions in the silver salts. In 1, each ligand supplies three N-donors to bridge two silver atoms to result in a chain structure, and all silver atoms in the chain possess the same coordination geometry. In 2, each ligand gives six N-donors to coordinate to two silver atoms of different geometries, forming a 1D chain. The changes in counteranions affect the coordination mode of the ligand and the geometry of the Ag(i) centre, and consequently give rise to complexes with different structures. The coordination features of the ligand have also been primarily investigated through density functional theory calculations.

Synthesis, structure and spectral and redox properties of new mixed ligand monomeric and dimeric Ru(ii) complexes: predominant formation of the “cis-α” diastereoisomer and unusual3MC emission by dimeric complexes

The tetradentate ligands 1,8-bis(pyrid-2-yl)-3,6-dithiaoctane (pdto) and 1,8-bis(benzimidazol-2-yl)-3,6-dithiaoctane (bbdo) form the complexes [Ru(pdto)(mu-Cl)](2)(ClO(4))(2) 1 and [Ru(bbdo)(mu-Cl)](2)(ClO(4))(2) 2 respectively. The new di-mu-chloro dimers 1 and 2 undergo facile symmetrical bridge cleavage reactions with the diimine ligands 2,2'-bipyridine (bpy) and dipyridylamine (dpa) to form the six-coordinate complexes [Ru(pdto)(bpy)](ClO(4))(2) 3, [Ru(bbdo)(bpy)](ClO(4))(2) 4, [Ru(pdto)(dpa)](ClO(4))(2) 5 and [Ru(bbdo)(dpa)](ClO(4))(2) 6 and with the triimine ligand 2,2':6,2''-terpyridine (terpy) to form the unusual seven-coordinate complexes [Ru(pdto)(terpy)](ClO(4))(2) 7 and [Ru(bbdo)(terpy)](ClO(4))(2) 8. In 1 the dimeric cation [Ru(pdto)(mu-Cl)](2)(2+) is made up of two approximately octahedrally coordinated Ru(II) centers bridged by two chloride ions, which constitute a common edge between the two Ru(II) octahedra. Each ruthenium is coordinated also to two pyridine nitrogen and two thioether sulfur atoms of the tetradentate ligand. The ligand pdto is folded around Ru(II) as a result of the cis-dichloro coordination, which corresponds to a "cis-alpha" configuration [DeltaDelta/LambdaLambda(rac) diastereoisomer] supporting the possibility of some attractive pi-stacking interactions between the parallel py rings at each ruthenium atom. The ruthenium atom in the complex cations 3a and 4 exhibit a distorted octahedral coordination geometry composed of two nitrogen atoms of the bpy and the two thioether sulfur and two py/bzim nitrogen atoms of the pdto/bbdo ligand, which is actually folded around Ru(II) to give a "cis-alpha" isomer. The molecule of complex 5 contains a six-coordinated ruthenium atom chelated by pdto and dpa ligands in the expected distorted octahedral fashion. The (1)H and (13)C NMR spectral data of the complexes throw light on the nature of metal-ligand bonding and the conformations of the chelate rings, which indicates that the dithioether ligands maintain their tendency to fold themselves even in solution. The bis-mu-chloro dimers 1 and 2 show a spin-allowed but Laporte-forbidden t(2g)(6)((1)A(1g))--> t(2g)(5) e(g)(1)((1)T(1g), (1)T(2g)) d-d transition. They also display an intense Ru(II) dpi--> py/bzim (pi*) metal-to-ligand charge transfer (MLCT) transition. The mononuclear complexes 3-8 exhibit dpi-->pi* MLCT transitions in the range 340-450 nm. The binuclear complexes 1 and 2 exhibit a ligand field ((3)MC) luminescence even at room temperature, whereas the mononuclear complexes 3 and 4 show a ligand based radical anion ((3)MLCT) luminescence. The binuclear complexes 1 and 2 undergo two successive oxidation processes corresponding to successive Ru(II)/Ru(III) couples, affording a stable mixed-valence Ru(II)Ru(III) state (K(c): 1, 3.97 x 10(6); 2, 1.10 x 10(6)). The mononuclear complexes 3-7 exhibit only one while 8 shows two quasi-reversible metal-based oxidative processes. The coordinated 'soft' thioether raises the redox potentials significantly by stabilising the 'soft' Ru(II) oxidation state. One or two ligand-based reduction processes were also observed for the mononuclear complexes.

A novel tin (II) dithioether complex

Organotin and related tin containing compounds are a recurring motif in organometallic chemistry. Here we report a new complex resulting from the reaction of tin (II) chloride with a dithioether diallyl ether ligand created as a side product from other research in our lab. This new complex is reasonably stable and can be synthesized on the bench top with no extraordinary measures required to exclude air or moisture. Its crystal structure reveals a five coordinate pseudo-square pyramidal geometry around tin, with the ligand binding the metal through its thioether sulfurs and the chlorides bridging.

Complexation of 1,4-Bis(phenylthio)butane on Mercury(II) Salts: Formation of Extended 2D Coordination Polymers

Two novel two-dimensional (2D) coordination polymers of stoichiometry [{PhS(CH2)4SPh}Hg2X4]n (X = Cl, 2a; X = Br, 2b) have been prepared by treatment of HgX2 with PhS(CH2)4SPh 1, acting as bridging dithioether ligand. The extended 2D structures result from bridging coordination of 1 between two mercury atoms and intermolecular Hg–X interactions, thus linking the HgX2 units in two dimensions. As established for 2a,b by single-crystal X-ray diffraction, the coordination around the Hg centers in both isomorphous compounds (monoclinic, space group P21/c) is distorted tetrahedral, with quite short Hg-thioether bonds of 2.4780(19) (2a) and 2.499(3) A (2b), respectively.

Allylic Alkylations Catalyzed by Palladium Systems Containing Modular Chiral Dithioethers. A Structural Study of the Allylic Intermediates

Palladium allylic systems containing modular chiral dithioether ligands were chosen as catalysts for a systematic study of homodonor ligands in allylic alkylation reactions. For this purpose, new t...

Cationic Iridium Complexes with Chiral Dithioether Ligands: Synthesis, Characterisation and Reactivity under Hydrogenation Conditions

AbstractA series of cationic IrI complexes containing chiral dithioether ligands have been prepared in order to study the influence of the sulfur substituents and the metallacycle size on the acetamidoacrylate hydrogenation reaction. In the case of complexes 6, 7 and 10, a mixture of diastereomers is observed in solution due to the sulfur inversion processes. In contrast, this fluxional behaviour is efficiently controlled by using bicyclic ligands which inhibit the S‐inversion in complexes 8 and 9. The solid‐state structure of complex 10b shows only one diastereomer with the sulfur substituents in a relative anti disposition and in an overall configuration of SCSCSSSS at the coordinated dithioether ligand. Iridium complexes containing seven‐ and six‐membered metallacycles (6b–d, 7b,c, 10a,b) react with the substrate through S‐ligand substitution, and the rate of this substitution is related to the position of the fluorine atom on the aromatic ring. On the contrary, complexes containing a bismetallacycle (8 and 9) are not displaced by the substrate. The catalytic hydrogenation activity of complexes 8 and 9 is analysed in terms of the high stability of the corresponding dihydride complexes (13 and 14). In both cases, only two of the four possible diastereomeric dihydride species are formed in solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

New silver(I) coordination architectures of pyridyl dithioether ligands with Ag⋯Ag, Ag⋯O, Ag⋯S and C–H⋯F weak interactions

In our continuous efforts to investigate the coordination architectures of silver(I) complexes with thioethers, we report herein the syntheses and crystal structures of three new silver(I) complexes, a trinuclear complex [ Ag 3 L 2 2 ( NO 3 ) 2 ] ( NO 3 ) ( CH 3 CN ) 2 and two one-dimensional chain complexes [Ag 2 L 1 (BF 4) 2(CH 3CN) 2] ∞ 1 and [Ag 2 L 3 (NO 3) 2] ∞ 3, where L 1 , L 2 and L 3 are three structurally related pyridyl dithioether ligands: 1,4-bis(2-pyridylthio)butane ( L 1 ), 1,5-bis(2-pyridylthio)pentane ( L 2 ) and 1,6-bis(2-pyridylthio)hexane ( L 3 ). The structural differences of 1, 2 and 3 show the influences of the ligand spacers on the coordination modes of the terminal pyridylsulfanyl groups and the coordination geometries of the Ag I ion. There exist Ag⋯Ag contacts in the three complexes, C–H⋯F weak hydrogen bonds in 1, Ag⋯S weak coordination bonds in 2 and Ag⋯O weak interactions in 2 and 3, and these weak interactions link the low-dimensional complexes into high-dimensional supramolecular structures and further stabilize the crystal structures in the solid states.

Novel dithioether–silver(i) coordination architectures: structural diversities by varying the spacers and terminal groups of ligands

An investigation into the dependence of the framework formation of coordination architectures on ligand spacers and terminal groups was reported based on the self-assembly of AgClO4 and eight structurally related flexible dithioether ligands, RS(CH2)nSR (Lan, R = ethyl group; Lbn, R = benzyl group, n= 1-4). Eight novel metal-organic architectures, [Ag(La1)3/2ClO4]n (1a), [Ag2(La2)2(ClO4)2]2 (2a), [AgLa3ClO4]n (3a), {[Ag(La4)2]ClO4}n (4a), [AgLb1ClO4]2 (1b), [Ag(Lb2)2]ClO4 (2b), {[Ag(Lb3)3/2(ClO4)1/2](ClO4)1/2}n (3b) and [Ag(Lb4)3/2ClO4]n(4b), were synthesized and structurally characterized by X-ray crystallography. Structure diversities were observed for these complexes: 1a forms a 2-D (6,3) net, while 2a is a discrete tetranuclear complex, in which the AgI ion adopts linear and tetrahedral coordination modes, and the S donors in each ligand show monodentate terminal and mu2-S bridging coordination fashions; 3a has a chiral helical chain structure in which two homo-chiral right-handed single helical chains (Ag-La3-)n are bound together through mu2-S donors, and simultaneously gives rise to left-handed helical entity (Ag-S-)n. In 4a, left- and right-handed helical chains formed by the ligands bridging AgI centers are further linked alternately by single-bridging ligands to form a non-chiral 2-D framework. 1b has a dinuclear structure showing obvious ligand-sustained Ag-Ag interaction, while 2b is a mononuclear complex; 3b is a 3-D framework formed by ClO4- linking the 2-D (6,3) framework, which is similar to that of 1a, and 4b has a single, double-bridging chain structure in which 14-membered dinuclear ring units formed through two ligands bridging two AgI ions are further linked by single-bridging ligands. In addition, a systematic structural comparison of these complexes and other reported AgClO4 complexes of analogous dithioether ligands indicates that the ligand spacers and terminal groups take essential roles on the framework formation of the AgI complexes, and this present feasible ways for adjusting the structures of such complexes by modifying the ligand spacers and terminal groups.

Synthesis and Molecular Structures of Platinum and Mercury Complexes Chelated by (Phenylthiomethyl)silane Ligands

AbstractMetathesis reaction of the dithioether complex cis‐[PtCl2{(PhSCH2)2SiPh2}] (2a) with NaBr and NaI yields the square planar complexes cis‐[PtX2{(PhSCH2)2SiPh2}] (2b, X = Br; 2c, X = I). The new compounds, which are fluxional in solution, have been studied by multinuclear NMR techniques; the crystal structures of 2a‐c have been determined by X ray diffraction. This series allows to evaluate the trans‐influence of the halide ligands on the lengths of the Pt‐S bonds, which increase from 227.26(12) (2a), 228.46(13) (2b) to 229.96(15) (2c) pm due to a more pronounced trans‐influence of I compared with Br and Cl. Complexation of (PhSCH2)2SiPh2 (1a) on HgBr2 gives the distorted tetrahedral compound [HgBr2{(PhSCH2)2SiPh2}] (3), having a quite loose coordination of the ligand both in solution and in the solid state [Hg‐S = 291.88(2) pm]. Alternatively, the coordination around Hg may be described as distorted square pyramidal in the solid state, since to due to a weak intermolecular Hg···Br interaction [346.72(13) pm], a dimeric motif is formed. Furthermore, the functionalised cyclic silane (PhSCH2)2SiC4H6 (1b) has been prepared and co‐ordinated as chelating dithioether ligands to [PtCl2(PhCN)2] affording the dithioether complex cis‐[PtCl2{(PhSCH2)2SiC4H6)}] (4). The crystal structure of 4 has also been determined by an X‐ray diffraction study.

A novel bimetallic macrocyclic Cu II complex with a flexible pyridyl dithioether ligand

A novel Cu II complex with a pyridyl dithioether ligand [Cu(L)Cl 2] 2 ( 1) [L=1,3-bis(2-pyridylthio)propane], has been synthesized and structurally characterized by X-ray diffraction analysis. Complex 1 crystallizes in monoclinic system, space group P2(1)/ n, a=14.208(5), b=8.586(3), c=14.309(5) Å, β=116.787(6)° and Z=4. In this complex, the ligand adopts N, N-bidentate coordination mode with two pyridine nitrogens in syn-form, and two ligands equivalently bridge two Cu II centers to form a 20-membered macrometallacyclic structure. Each Cu II center is four-coordinated by two nitrogen donors from two distinct L ligands and two chloride anions in trans-form. In addition, the weak C–H⋯Cl hydrogen-bonding interactions link these dimeric units into a three-dimensional supramolecular architecture.

New Silver(I) Complexes of Pyridyl Dithioether Ligands with Ag–Ag Interactions: Effects of Anions and Ligand Spacers on the Framework Formations of Complexes

Three new silver(I) complexes existing Ag–Ag interactions, a trinuclear cluster complex [Ag3(L1)2(NO3)2](NO3) 1, a dinuclear complex [Ag2(L1)2](PF6)22 and a one-dimensional chain complex [Ag2L2(NO3)2]∞3, where L1 and L2 are two structurally related pyridyl dithioether ligands, bis(2-pyridylthio)methane (L1) and 1,3-bis(2-pyridylthio)-propane (L2), have been synthesized and their structures were determined by single-crystal X-ray diffraction analysis. The striking structural differences of 1 and 2 suggest that counter anions have a profound effect upon the framework formations of silver complexes with pyridyl dithioether ligands, and the differences of 1 and 3 indicate that the subtle changes of the space groups have great influence on the coordination modes of the terminal pyridylsulfanyl groups and the geometries of AgI ion and therefore greatly influence the structures of their complexes. The weak Ag⋅⋅⋅O interactions in the trinuclear complex 1 and the one-dimensinoal chain complex 3 extend them into quasi two-dimensional networks, and the Ag⋅⋅⋅S weak interactions in the dinuclear complex 2 into one-dimensinoal chains, and such weak interactions further stabilized these complexes.

Structural Diversities of Silver(I) Coordination Compounds with Flexible Dithioether Ligands Based upon Changing the Ligand Spacers

To investigate the influences of ligand spacers of flexible bis(thioether) bridging ligands on the framework formations of their complexes, six new AgI coordination compounds with a series of structurally related bis(tert-butylthio)alkane ligands, Ln = (CH3)3CS-(CH2)n-SC(CH3)3 where n = 1−6, [(AgL1)ClO4]n (1), {[Ag(L2)1.5]ClO4}n (2), [(AgL3)ClO4]2 (3), {[Ag(L4)1.5]ClO4}n (4), [(AgL5)ClO4]2 (5), and {[Ag(L6)1.5]ClO4}n (6), have been synthesized and structurally characterized by elemental analysis, IR, 1H NMR spectra, and X-ray crystallography. In 1, the AgI centers are linked by bridging L1 to form a one-dimensional (1-D) zigzag chain, and complex 2 has an extended two-dimensional (2-D) (6,3) topologic array with hexagonal 30-membered macrometallacycles. Complexes 3 and 5 show similar discrete dinuclear structures. Complexes 4 and 6 consist of single-double bridging chains in which dinuclear macrometallacycles are further linked by single bridging L ligands. The differences among these structures indicate ...

(Phenylthiomethyl)silanes and (butyltelluromethyl)silanes as novel bifunctional ligands for the construction of dithioether-, ditelluroether- and transition metal–silicon complexes

The functionalized silanes (PhSCH 2) 2SiPh 2 ( 1a), (PhSCH 2) 2Si(vinyl)Me ( 1b), (PhSCH 2) 2Si(H)Me ( 1c) and (PhSCH 2) 3SiH ( 1d) have been prepared and co-ordinated as chelating dithioether ligands or via a covalent MSi bond to various transition metal centers. Thus, reaction of 1a with [PtCl 2(PhCN) 2] affords the dithioether complex cis-[PtCl 2{(PhSCH 2) 2SiPh 2}] ( 3), which exist in solution as mixtures of dl- and meso-invertomers. Treatment of [Re(μ-Br)(CO) 3THF] 2 with 1a– c yielded the stereochemically rigid chelate complexes fac-[ReBr(CO) 3{(PhSCH 2) 2SiR 1R 2}] (R 1, R 2=Ph ( 4a)), (R 1=vinyl, R 2=Me ( 4b)), (R 1=H, R 2=Me ( 4c)). Due to the presence of two different substituents R 1 and R 2 on Si, 4b and 4c are isolated as 50:50 mixtures of diastereomers. The presence of a SiH function in 1c, d can be exploited for SiH activation reactions. Thus, oxidative addition on [Pt(PPh 3) 2(CH 2CH 2)] yields the fluxional hydrido silyl complex [Pt(H)(PPh 3) 2{Si(CH 2SPh) 2Me}] ( 5a) and the rigid derivative [Pt(H)(PPh 3) 2{Si(CH 2SPh) 3}] ( 5b). The ditelluroether complexes cis-[PtCl 2{(RTeCH 2) 2SiMe 2)] ( 6a, R=Ph), ( 6b, R=n-Bu) are obtained by treatment of [PtCl 2(PhCN) 2] with (PhTeCH 2) 2SiMe 2 ( 2a) and (n-BuTeCH 2) 2SiMe 2 ( 2b), respectively. The complex fac-[ReBr(CO) 3{(n-BuTeCH 2) 2SiMe 2}] ( 7) results from the reaction of [Re(μ-Br)(CO) 3THF] 2 with ( 2b). The new compounds have been studied by multinuclear NMR techniques, the crystal structures of 3, 4a, 5 and 6b have been determined by X-ray diffraction studies.

Modifying silver(I) coordination frameworks containing a flexible dithioether ligand by variation of counter anions

Two silver(I) coordination architectures with the flexible ligand 1,6-bis(phenylthio)hexane (L) have been synthesized and their crystal structures determined by X-ray diffraction analysis. Different frameworks were observed in the two complexes due to variation of the counter anions. The dinuclear complex [Ag(L)(ClO4)]2 (1) has a cage structure with the perchlorate anions coordinated to the two silver(I) ions in a rare η2 bridging mode. However, in the complex [Ag(L)(NO3)]n (2) there is a 2D network with monatomic bridging nitrate anions. The results show the great influence of counter anions on building metal–organic supramolecular structures. In addition, the different conformations of the flexible ligand L in the frameworks of 1 and 2 indicate its ready adaptability to various coordination environments.

Arsenic(III) halide complexes with acyclic and macrocyclic thio- and selenoether coligands: synthesis and structural properties.

The preparations of the new complexes [AsBr(3)[MeS(CH(2))(2)SMe]], [AsX(3)([9]aneS(3))] (X = Cl, Br or I; [9]aneS(3) = 1,4,7-trithiacyclononane), [AsCl(3)([14]aneS(4))] ([14]aneS(4) = 1,4,8,11-tetrathiacyclotetradecane), [AsX(3)([8]aneSe(2))] ([8]aneSe(2) = 1,5-diselenacyclooctane), [(AsX(3))(2)([16]aneSe(4))] ([16]aneSe(4) = 1,5,9,13-tetraselenacyclohexadecane), and [(AsBr(3))(2)([24]aneSe(6))] ([24]aneSe(6) = 1,5,9,13,17,21-hexaselenacyclotetracosane) are described. These are obtained from direct reaction of the appropriate AsX(3) and 1 mol equiv of the thio- or selenoether ligand in anhydrous CH(2)Cl(2) (or thf for X = I) solution. The products have been characterized by microanalysis and IR and (1)H NMR spectroscopy. In solution they are extensively dissociated, reflecting the weak Lewis acidity of AsX(3). Reaction of AsX(3) with MeSe(CH(2))(2)SeMe or MeC(CH(2)EMe)(3) (E = S or Se) gave only oils. Treatment of PCl(3) or PBr(3) with Me(2)S, MeE(CH(2))(2)EMe, or [9]aneS(3) failed to give solid complexes, and there was no evidence from NMR spectroscopy for any adduct formation in solution. The crystal structures of the first series of thioether and selenoether complexes of As(III) are described: [AsBr(3)[MeS(CH(2))(2)SMe]], C(4)H(10)AsBr(3)S(2), a = 10.2818(6) A, b = 7.8014(5) A, c = 14.503(1) A, beta = 102.9330(2) degrees, monoclinic, P2(1)/c, Z = 4; [AsI(3)[MeS(CH(2))(2)SMe]], C(4)H(10)AsI(3)S(2), a = 9.1528(1) A, b = 11.5622(2) A, c = 12.0939(2) A, beta = 93.863(1) degrees, monoclinic, P2(1)()/n, Z = 4; [AsCl(3)([9]aneS(3))], C(6)H(12)AsCl(3)S(3), a = 17.520(4) A, b = 17.520(4) A, c = 16.790(7) A, tetragonal, I4(1)cd, Z = 16; [AsCl(3)([14]aneS(4))], C(10)H(20)AsCl(3)S(4), a = 13.5942(2) A, b = 7.7007(1) A, c = 18.1270(3) A, beta = 111.1662(5) degrees, monoclinic, P2(1)()/n, Z = 4; [(AsCl(3))(2)([16]aneSe(4))], C(12)H(24)As(2)Cl(6)Se(4), a = 9.764(3) A, b = 13.164(1) A, c = 10.627(2) A, beta = 114.90(1) degrees, monoclinic, P2(1)()/n, Z = 2; [(AsBr(3))(2)([16]aneSe(4))], C(12)H(24)As(2)Br(6)Se(4), a = 10.1220(1) A, b = 13.4494(2) A, c = 10.5125(2) A, beta = 113.49(2) degrees, monoclinic, P2(1)()/n, Z = 2. [AsBr(3)[MeS(CH(2))(2)SMe]] and [AsI(3)[MeS(CH(2))(2)SMe]] reveal discrete mu(2)-halo As(2)X(6) dimeric structures involving distorted octahedral As(III), with the dithioether ligand chelating. [AsCl(3)([9]aneS(3))] adopts a discrete molecular distorted octahedral geometry with the thioether behaving as a weakly coordinated fac-capping ligand. [AsCl(3)([14]aneS(4))] forms an infinite sheet involving two mu(2)-chloro ligands on each As but bridging to two distinct As centers. Each macrocycle coordinates to two adjacent As centers via one S atom, giving a cis-octahedral Cl(4)S(2) donor set at As(III). The structures of [(AsCl(3))(2)([16]aneSe(4))] and [(AsBr(3))(2)([16]aneSe(4))] adopt 2-dimensional sheet structures with mu(2)-dihalo As(2)X(6) dimers cross-linked by mu(4)-tetraselenoether macrocycles, giving a disorted cis-X(4)Se(2) donor set at each As center. These species are compared with their antimony(III) and bismuth(III) analogues where appropriate.

Syntheses and crystal structures of new mono- and di-nuclear platinum(II) complexes with dithioether ligands

Two new platinum(II) complexes with dithioether ligands, cis-[Pt( L 1 )Cl 2] ( 1) and cis-[Pt( L 2 )Cl 2] 2 ( 2), where L 1 =1,3-bis(phenylthio)propane and L 2 =1,5-bis( n-propylthio)pentane, have been synthesized and structurally characterized by X-ray diffraction analyses. In 1, the Pt(II) center is four-coordinated and forms a six-membered chelated ring with L 1 , while 2 exhibits a unique di-nuclear structure containing a 16-membered metallomacrocyles with chair-shaped conformation, in which each Pt(II) center is coordinated by two chloride anions and two sulfur-donors from two L 2 ligands.

Novel chiral dithioethers derived from l-tartaric acid

The synthesis of a new family of systematically modified chiral dithioethers to be used as ligands is described. Phenylthioether derivative 5 and fluorine-containing dithioether ligands 6– 8 and 13– 15 were prepared by direct reaction of phenylthiol and o-, m- or p-fluorophenylthiol with two different ditriflate derivatives based on the l-tartaric skeleton. The chiral ditriflate 12 containing a dioxolane moiety was reacted with ethane- and propanedithiol, producing cyclic dithioethers 16 and 17, respectively, in good yields (≈50%). The analogous ditriflate 4 with benzyl ether protecting groups, having a skeleton without restricted rotation, gave the thiolane 9 as the main product.

Reactivity of technetium(I) thioether carbonyl complexes towards histidine—an EXAFS study in solution

Technetium(I) thioether carbonyl complexes and their reaction products with histidine were prepared and characterised by Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, various chromatographic and electrophoretic methods and electrospray mass spectrometry. Their behaviour in aqueous solutions was studied on the carrier-added ( 99Tc) and the no-carrier-added ( 99mTc) levels. HPLC and electrophoretic studies show the identity of reaction products at both concentration levels. Technetium(I) carbonyl complexes containing a bidentate dithioether ligand [Tc(CO) 3Cl(SS)], as well as a tridentate carboxylato thioether ligand [Tc(CO) 3(SSO)], undergo a ligand exchange reaction with histidine and form the complex [Tc(CO) 3His]. EXAFS measurements were performed to estimate the structural parameters of the dissolved technetium(I) carbonyl complexes and their reaction products after the challenge experiments. The calculated bond lengths and coordination numbers are in agreement with the expected values and confirm the ligand exchange reactions.