The conformation and orientation of copper(II)-bleomycin intercalated with DNA

EPR data are used to describe the conformation and identity of the atoms coordinated to Cu(II) in Cu(II)-bleomycin bound to oriented DNA fibers. The fibers were slowly drawn from viscous solutions of Cu(II)-bleomycin-DNA containing one Cu(II)-bleomycin to 200 basepairs. EPR measurements were made at room temperature and 90 K for different orientations of the external magnetic field with respect to the helical axes of the fibers. The g-values ($\text{g}{}_{\mathrm{}}\text{=2.21}$, g_⊥ =2.04) and the hyperfine constant ($\text{A}{}_{\mathrm{}}\text{=175}\text{G}$) are consistent with values expected for Cu(II) chelated to a square planar array of ligands. In the oriented fibers, the square planar arrays do not all have the same orientations with respect to the fiber axes. At room temperature the chelated ions have rotational freedom in which the normal to the planar array has almost complete freedom of rotation about axes perpendicular to the DNA fiber axes. The normal maintains an angle of 75° with respect to the axis, in the plane of the basepair, about which it rotates. Nine superhyperfine peaks on the high field side of the EPR spectrum were partially resolved. The number and splitting (12 G) of these superhyperfine peaks indicate that four nitrogen atoms are chelated to Cu(II) in a square planar array. These data on Cu(II)-bleomycin bound to DNA give information on the orientation of the metal-containing portion of bleomycin which lies outside the double helix.     

Can geometry control the coordination behaviour of 2-hydroxy-1-naphthaldehyde-N(4)-phenylthiosemicarbazone? A study towards its origin

2-Hydroxy-1-naphthaldehyde-N(4)-phenylthiosemicarbazone [H₂-Nap-ptsc] (H₂L) was reacted with square planar complexes of the type [MCl₂(EPh₃)₂] (where M = Ni or Pd; E = P or As) and octahedral [RuHCl(CO)(PPh₃)₃]. Square planar complexes ([Ni(Nap-ptsc)PPh₃)]; [Pd(Nap-ptsc)PPh₃)]; [Pd(Nap-ptsc)AsPh₃)]) gave products with only ONS tri coordinated thiosemicarbazone whereas octahedral ruthenium complex gave two products, one with NS and the other with ONS coordination. It is interesting to note that NS bi coordination leads to the formation of more strained four member ring. All the new complexes have been characterised by analytical, spectral, crystallographic and electrochemical methods.     

Ruthenium mediated C-H activation of benzaldehyde thiosemicarbazones: Synthesis, structure and, spectral and electrochemical properties of the resulting complexes

Reaction of five 4R-benzaldehyde thiosemicarbazones (R = OCH₃, CH₃, H, Cl and NO₂) with [Ru(PPh₃)₃(CO)(H)Cl] in refluxing methanol in the presence of a base (NEt₃) affords complexes of two different types, viz. 1-R and 2-R. In the 1-R complexes the thiosemicarbazone is coordinated to ruthenium as a dianionic tridentate C,N,S-donor via C-H bond activation. Two triphenylphosphines and a carbonyl are also coordinated to ruthenium. The tricoordinated thiosemicarbazone ligand is sharing the same equatorial plane with ruthenium and the carbonyl, and the PPh₃ ligands are mutually trans. In the 2-R complexes the thiosemicarbazone ligand is coordinated to ruthenium as a monoanionic bidentate N,S-donor forming a four-membered chelate ring with a bite angle of 63.91(11)°. Two triphenylphosphines, a carbonyl and a hydride are also coordinated to ruthenium. The coordinated thiosemicarbazone ligand, carbonyl and hydride constitute one equatorial plane with the metal at the center, where the carbonyl is trans to the coordinated nitrogen of the thiosemicarbazone and the hydride is trans to the sulfur. The two triphenylphosphines are trans. Structures of the 1-CH₃ and 2-CH₃ complexes have been determined by X-ray crystallography. All the complexes show intense transitions in the visible region, which are assigned, based on DFT calculations, to transitions within orbitals of the thiosemicarbazone ligand. Cyclic voltammetry on the complexes shows two oxidations of the coordinated thiosemicarbazone on the positive side of SCE and a reduction of the same ligand on the negative side.     

Preparation and crystal structure of bis(acetato)(trans-1,2-diaminocyclohexane)platinum(II)

The structure of the complex [Pt(trans-1,2-di- aminocyclohexane) (acetate)₂]·H₂O has been determined by X-ray diffraction. This racemic compound is orthorhombic, space group Aba2, a = 20.813(9), b = 7.926(5), c = 17.296(8) Å, Z = 8. The structure was refined on 1214 nonzero Cu Kα reflections to R = 0.028. The square planar environment of Pt includes the amino groups of the diamine in cis positions and oxygens from two monodentate acetates. The PtN and PtO distances average 2.00(3) and 2.02(3) Å, respectively. The bite of the diamine ligand imposes a NPtN angle of 85(1)°, whereas the small OPtO angle of 85(1)° probably results from packing effects. The average plane through the puckered cyclohexyl ring makes an angle of 19° with the PtN₂O₂ plane. The molecules are stacked by pairs along the b axis. The two molecules of each pair are 180° apart about the stacking axis, and form altogether four NH···O hydrogen bonds.     

Preparation and crystal structure of the hydroxo-bridged complex biscyclo-tri-μ-hydroxo-tris[(trans-1,2-diaminocyclohexane)platinum(II)] tris

The title compound, [C₁₈H₄₅N₆O₃Pt₃]2(SO₄)₃·14H₂O, belongs to space group C2/c, with a = 25.90(2) Å, b = 14.33(2) Å, c = 23.74(3) Å, β = 122.88(7)°, and Z = 4. The structure was refined on 2899 independent nonzero reflections to an R factor of 0.042. The crystal contains hydroxobridged cyclic [Pt₃(OH)₃(C₆H₁₄N₂)₃]³⁺ ions, in which the Pt₃O₃, ring has a chair conformation. The coordination around each Pt atom is square planar and the cyclohexyl ring lies roughly in the same plane. A large cavity between two trimeric ions related by a twofold axis is filled with one SO₄^2- ion and five water molecules, which participate in an intricate network of hydrogen bonds among themselves and with the hydroxo and amino groups of the complex cation. These units are held together in the crystal by stacking interactions between Pt(OH)₂(C₆H₁₄N₂) “planes” belonging to adjacent molecules, as well as by hydrogen bonds involving the remaining SO₄^2- ions and water molecules. The presence of the cyclohexane ring precludes λ-δ interconversion in the chelate ring and imparts rigidity to the Pt(trans-dach)²⁺ unit.     

The conformation and orientation of copper (II)-bleomycin intercalated with DNA

EPR data are used to describe the conformation and identity of the atoms coordinated to Cu(II) in Cu(II)-bleomycin bound to oriented DNA fibers. The fibers were slowly drawn from viscous solutions of Cu(II)-bleomycin-DNA containing one Cu(II)-bleomycin to 200 basepairs. EPR measurements were made at room temperature and 90 K for different orientations of the external magnetic field with respect to the helical axes of the fibers. The g-values (g parallel = 2.21, g perpendicular = 2.04) and the hyperfine constant (A parallel = 175 G) are consistent with values expected for Cu(II) chelated to a square planar array of ligands. In the oriented fibers, the square planar arrays do not all have the same orientations with respect to the fiber axes. At room temperature the chelated ions have rotational freedom in which the normal to the planar array has almost complete freedom of rotation about axes perpendicular to the DNA fiber axes. The normal maintains an angle of 75 degrees with respect to the axis, in the plane of the basepair, about which it rotates. Nine superhyperfine peaks on the high field side of the EPR spectrum were partially resolved. The number and splitting (12 G) of these superhyperfine peaks indicate that four nitrogen atoms are chelated to Cu(II) in a square planar array. These data on Cu(II)-bleomycin bound to DNA give information on the orientation of the metal-containing portion of bleomycin which lies outside to double helix.     

The X-ray crystal structures of [Hg(C6F4OH-p)2OH2] and [Hg(C6H4OMe-p)(O2CC6F4OMe-p)] - Factors influencing supramolecular Hg-O interactions

An X-ray crystal structure has shown that the previously reported bis(p-hydroxytetrafluorophenyl)mercury crystallises as a monohydrate [Hg(C₆F₄OH-p)₂(OH₂)] exhibiting rare coordination of water to a diorganomercurial. The stereochemistry of the three-coordinate mercury is T-shaped with the water coordinated perpendicular to the near linear C-Hg-C unit. The molecules are linked in chains by hydrogen bonding between the hydroxy groups, and the chains into layers by hydrogen bonding between the water oxygen and an OH group. Thermogravimetric analysis shows two water molecules are eliminated together, both the coordinated water and one formed through condensation of the linked -OH groups. In [Hg(p-MeOC₆H₄)(O₂CC₆F₄OMe-p)], molecules with a near linear strongly bonded C-Hg-O arrangement are observed. These are linked into a linear polymer through Hg-O (carboxylate) bridges giving alternate four-membered and eight-membered rings giving mercury overall square planar stereochemistry.     

Control of crystal forms of apoferritin by site-directed mutagenesis

Surface charges of protein molecules are not only important to biological functions but also crucial to the molecular assembly responsible for crystallization. Appropriate alteration in the surface charge distribution of a protein molecule induces new molecular alignment in the proper direction in the crystal and, hence, controls the crystal form. Apoferritin molecules are known to crystallize in two- and three-dimensional forms in the presence of cadmium ions, which bridge neighboring protein molecules. Here we report a controlled transformation of the apoferritin 2-D crystal by site-directed mutagenesis. In mutant apoferritin, two amino acid residues binding a cadmium-ion through their negative charge, were replaced by one type of nonionic amino acid residues. The amino acid residues, Asp-84 and Gln-86 in the sequence of recombinant (i.e., wild-type) horse L -apoferritin, were replaced by Ser. The wild-type apoferritin yielded a hexagonal lattice 2-D crystal in the presence of cadmium ions. In contrast, the mutant apoferritin yielded two types of oblique crystals independent of the presence of cadmium ions. Image reconstruction of electron micrographs of the mutant crystals made clear that the mutant apoferritin molecules oriented themselves with the 2-fold symmetry axis perpendicular to the crystal plane in both crystals, while the wild-type apoferritin molecules oriented themselves with the 3-fold symmetry axis perpendicular to the crystal plane. The changes of crystal forms and molecular orientation in the 2-D crystals were well explained by a change of the electrostatic interactions induced by the mutagenesis. © 1995 Wiley-Liss, Inc.     

Synthesis and crystal structure of a tetranuclear five-coordinated copper(II) complex with Schiff-base of N-(3-carboxylsalicylidene)-4-(2-iminoethyl)-morpholine

A tetranuclear copper(II) complex [Cu₄L₂(CH₃COO)₂(OH)₂]·6H₂O, in which L stands for the dianion of N-(3-carboxylsalicylidene)-4-(2-iminoethyl)morpholine, was synthesized and characterized by elemental analysis, IR, UV-Vis, TGA and X-ray single crystal diffraction. The crystal structure shows that the coordination unit is centrosymmetric with all the Cu(II) ions in square pyramidal coordination geometry. The coordination unit consists of two equivalent parts [Cu₂L(CH₃COO)(OH)], each containing two Cu(II) ions, a tetradentate N₂O₂ Schiff base dianion L²⁻, a CH₃COO⁻, and a OH⁻ anion. In [Cu₂L(CH₃COO)(OH)], the six coordination atoms (N₂O₄) are nearly coplanar, with Cu(1) and Cu(2) enchased in between; the phenolate oxygen and the OH⁻ oxygen as bridging atoms bind the two Cu(II) ions in close proximity; both O₄ around Cu(1) and N₂O₂ around Cu(2) form the basal plane of the coordination square pyramids. The two parts are connected by sharing two μ₃-OH⁻ oxygens and two μ₂-CH₃COO⁻ oxygens from each other, forming four edge-sharing coordination square pyramids around the four Cu(II) ions. A 3D network is formed through hydrogen bonding along a and c axis, and π-π interaction along b axis.     

Effect of Coordinated Ions on Structure and Flexibility of Parallel G-quadruplexes: A Molecular Dynamics Study

Abstract

Single tract guanine residues can associate to form stable parallel quadruplex structures in the presence of certain cations. Nanosecond scale molecular dynamics simulations have been performed on fully solvated fibre model of parallel d(G₇) quadruplex structures with Na⁺ or K⁺ ions coordinated in the cavity formed by the O6 atoms of the guanine bases. The AMBER 4.1 force field and Particle Mesh Ewald technique for electrostatic interactions have been used in all simulations. These quadruplex structures are stable during the simulation, with the middle four base tetrads showing root mean square deviation values between 0.5 to 0.8 Å from the initial structure as well the high resolution crystal structure. Even in the absence of any coordinated ion in the initial structure, the G-quadruplex structure remains intact throughout the simulation. During the 1.1 ns MD simulation, one Na⁺ counter ion from the solvent as well as several water molecules enter the central cavity to occupy the empty coordination sites within the parallel quadruplex and help stabilize the structure. Hydrogen bonding pattern depends on the nature of the coordinated ion, with the G-tetrad undergoing local structural variation to accommodate cations of different sizes. In the absence of any coordinated ion, due to strong mutual repulsion, O6 atoms within G-tetrad are forced farther apart from each other, which leads to a considerably different hydrogen bonding scheme within the G-tetrads and very favourable interaction energy between the guanine bases constituting a G-tetrad. However, a coordinated ion between G-tetrads provides extra stacking energy for the G-tetrads and makes the quadruplex structure more rigid. Na⁺ ions, within the quadruplex cavity, are more mobile than coordinated K⁺ ions. A number of hydrogen bonded water molecules are observed within the grooves of all quadruplex structures.     

New type of arrangement of rare-earth quinolinolate. Molecular structure of scandium 2-methyl-8-quinolinolate

The tetrakis 2-methyl-8-quinolinolate scandium complex [Sc(q^Me)₄(H)] (1) have been prepared by the reaction of ScCl₃ with 2-methyl-8-quinolinol (Hq^Me) in methanol in the presence of aqueous ammonia. The X-ray diffraction analysis has shown that a molecule of (1) has a propeller like shape herein the Sc(III) ion is surrounded by four methylquinolinolate ligands two of which are chelate but the other two are monodentate and one of these monodentate methylquinolinolate ligands contains hydrogen atom at nitrogen atom. Furthermore there are two molecules of water per one complex molecule not coordinated to the Sc cation that is not typical for rare-earth compounds.     

Structure–activity relationship study of copper(II) complexes with 2-oxo-1,2-dihydroquinoline-3-carbaldehyde (4′-methylbenzoyl) hydrazone: synthesis, structures, DNA and protein interaction studies, antioxidative and cytotoxic activity

Novel 2-oxo-1,2-dihydroquinoline-3-carbaldehyde (4′-methylbenzoyl) hydrazone (H₂L) (1) and its two copper(II) complexes have been synthesized. Single-crystal X-ray diffraction studies revealed that the structure of the new copper(II) chloride complex, [Cu(H₂L)Cl₂]·2H₂O (2), is square pyramidal and that of the copper(II) nitrate complex, [Cu(HL)NO₃]·DMF (3), is square planar. In 2, the copper atom is coordinated by the ligand with ONO donor atoms, one chloride ion in the apical position, and the other chloride in the basal plane. In 3, the ligand coordinates as a uninegative tridentate ONO⁻ species and with one nitrate ion in the basal plane. DNA binding experiments indicated that the ligand and copper(II) complexes can interact with DNA through intercalation. Bovine serum albumin binding studies revealed that the compounds strongly quench the intrinsic fluorescence of bovine serum albumin through a static quenching process. Antioxidative activity tests showed that 1 and its copper(II) complexes have significant radical scavenging activity against free radicals. Cytotoxic activities of the ligand and copper(II) complexes showed that the two copper(II) complexes exhibited more effective cytotoxic activity against HeLa and HEp-2 cells than the corresponding ligand. The entire biological activity results showed that the activity order was 1 < 2 < 3.     

Uranyl nitrate complexes of some Schiff bases of 4-aminoantipyrine and certain carbonyl compounds

A series of nine complexes of uranyl nitrate with some Schiff bases derived from 4-aminoantipyrine and certain carbonyl compounds, such as benzaldehyde, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4- methylbenzaldehyde, 4-N,N-dimethylaminobenzaldehyde, 2-hydroxybenzaldehyde, 2-hydroxy-1-naphthaldehyde, acetylacetone and benzoylacetone have been synthesized. These complexes have been characterized by elemental analysis, molecular weight determination and IR spectral, conductance and magnetic studies. From these studies they can be formulated as [UO₂L₂(NO₃)₂], in which the first five ligands (in the order given above) and nitrate ions are coordinated bidentately, while the last four ligands (which have either a phenolic hydroxyl group or a side-chain carbonyl group as an additional site) act as terdentate ligands, and nitrate ions are coordinated monodentately. Hence the proposed general formula for the complexes suggests that the uranyl ion has a coordination number of eight in addition to the two oxygen atoms which have already been bonded to the U(VI) species.     

A Nanosecond Molecular Dynamics Study of Antiparallel d(G)7 Quadruplex Structures: Effect of the Coordinated Cations

Abstract

Nanosecond scale molecular dynamics simulations have been performed on antiparallel Greek key type d(G₇) quadruplex structures with different coordinated ions, namely Na⁺ and K⁺ ion, water and Na⁺ counter ions, using the AMBER force field and Particle Mesh Ewald technique for electrostatic interactions. Antiparallel structures are stable during the simulation, with root mean square deviation values of ～ 1.5 Å from the initial structures. Hydrogen bonding patterns within the G-tetrads depend on the nature of the coordinated ion, with the G-tetrad undergoing local structural variation to accommodate different cations. However, alternating syn-anti arrangement of bases along a chain as well as in a quartet is maintained through out the MD simulation. Coordinated Na+ ions, within the quadruplex cavity are quite mobile within the central channel and can even enter or exit from the quadruplex core, whereas coordinated K⁺ ions are quite immobile. MD studies at 400K indicate that K⁺ ion cannot come out from the quadruplex core without breaking the terminal G-tetrads. Smaller grooves in antiparallel structures are better binding sites for hydrated counter ions, while a string of hydrogen bonded water molecules are observed within both the small and large grooves. The hydration free energy for the K⁺ ion coordinated structure is more favourable than that for the Na⁺ ion coordinated antiparallel quadruplex structure.     

Cyclic peptide-metal salt adducts. I. crystal structure of the hexaquocopper(II) perchlorate cyclosarcosylsarcosine 1:2 adducts

The crystal structure analysis of the 2:1 adduct of cyclosarcosylsarcosine with copper(II) perchlorate shows that the independent unit is composed of six water molecules octahedrally coordinated to the Cu(II) ion, two tetrahedral perchlorate ions and four independent halves of cyclosarcosylsarcosine molecules lying on crystallographic centers of symmetry. All available hydrogens of water molecules are involved in hydrogen bonding as donors and all carbonyl oxygen atoms of the cyclic peptide molecules function as acceptors. Two other oxygen atoms for each perchlorate anion participate in the hydrogen bonding scheme, which leads to the absence of the orientational disorder usually observed in these ions. Layers of inorganic material and layers of organic material, roughly parallel to the ab plane, pack alternatively with each other. Electrostatic and ion-dipole interactions together with hydrogen bonds are responsible for the building up of the crystals.     

A novel complex of mercury with double η-π-aryl interactions

(MesTe)₂ reacts with HgBr₂ to give [(HgBr₂TeMes₂)₂HgBr₂], a polymeric one-dimensional assembly of (μ-Br)Hg and alternating mercury···η⁶-π-aryl interactions. This polymeric structure is based on [{HgBr₂(TeMes₂)}₂HgBr₂] centrosymmetric units with three mercury atoms having two different coordination geometries. The central Hg^II ion is coordinated to four bromine atoms in the same plane and to two mesityl groups from TeMes₂ via η⁶-π-aryl interactions. Each TeMes₂ is bonded to one of the surrounding Hg^II ions through the tellurium atom. The central Hg^II ion is located in a crystallographic centre of inversion and sandwiched by its coordinating mesityl groups. The [{HgBr₂(TeMes₂)}₂HgBr₂] units are linked by weak Hg···Br interactions in chains running along the c-axis.     

Interactions between metal ions and carbohydrates. Syntheses and spectroscopic studies of several lanthanide nitrate–d-galactitol complexes

Two complexes of neutral d-galactitol (C₆H₁₄O₆, G) with terbium nitrate, TbGN(I) and TbGN(II), and one complex with samarium nitrate SmGN were synthesized and characterized. From IR, FIR, THz and luminescence spectra the possible coordinations were suggested, and the single-crystal X-ray diffraction results confirm the spectroscopic conclusions. In TbGN(I) (Tb(NO₃)₃·C₆H₁₄O₆·3H₂O), the Tb³⁺ is 9-coordinated with three water molecules and six OH groups from two d-galactitol molecules. Nitrate ions do not coordinate to metal ions, which is different from other reported lanthanide nitrate–d-galactitol complexes. In TbGN(II) and SmGN (Ln(NO₃)₃·C₆H₁₄O₆), Ln³⁺ is 10-coordinated with six OH groups from two d-galactitol molecules and four oxygen from two bidentate nitrate ions, and one nitrate ion is hydrogen bonded. No water exists in the structures. d-Galactitol molecules provide their 1-, 2- and 3-hydroxyl groups to coordinate with one metal ion and their 4-, 5- and 6-hydroxyl groups to coordinate with another metal ion in the three structures. There is still a new topological structure that can be observed for lanthanide–d-galactitol complexes, which indicates that the coordinations between hydroxyl groups and metal ions are complicated.     

Heterometallic complexes derived from ruthenocene-functionalized dipyrromethenes

A new ligand based on a ruthenocene moiety appended by a diyrromethene (Rc-dpm) was synthesized. Two copper complexes, Cu(Rc-dpm)₂ (3) and Cu(Rc-dpm)acac (4), and one cobalt complex, Co(Rc-dpm)₃, 5, were prepared from the ligand. These complexes were characterized by a combination of UV-Vis spectroscopy, elemental analysis, and X-ray crystallography. Copper(II) complex 3 was found to be coordinated by two dipyrromethene ligands in a distorted square planar environment around the copper while complex 4 had one dipyrromethene ligand and an acac coordinated in a nearly idealized square planar copper geometry. The cobalt(III) complex 5 has an octahedral geometry around the cobalt via the coordination of three dipyyromethene ligands.     

Interaction of Cu(II)with His-Val-Gly-Asp and of Zn(II) with His-Val-His,Two Peptides at the Active Site of Cu,Zn-Superoxide Dismutase

His-Val-His and His-Val-Gly-Asp are two naturally occurring peptide sequences, present at the active site of Cu,Zn-superoxide dismutase (Cu,Zn-SOD). We have already studied the interaction of His-Val-His=A (copper binding site) with Cu(II) and of His-Val-Gly-Asp=B (zinc binding site) with Zn(II). As a continuation of this work and for comparison purposes we have also studied the interaction of Zn(II) with His-Val-His and Cu(II) with His-Val-Gly-Asp using both potentiometric and spectroscopic methods (visible, EPR, NMR). The stoichiometry, stability constants and solution structure of the complexes formed have been determined. Histamine type of coordination is observed for/ZnAH/²⁺, /ZnA/⁺, /ZnA²H/⁺ and/ZnA²/ in acidic pH while deprotonation of coordinated water molecules is observed at higher pH. /CUB/ species is characterized by the formation of a macrochelate and histamine type coordination. Its stability results in the suppression of amide deprotonation which occurs at high pH resulting in the formation of the highly distorted from square planar geometry 4N complex/CuBH_-3/³.     

Reactions and structures in the gallium(III)/indium(III)-N,N-dimethylthioformamide systems

The structure of the N,N-dimethylthioformamide (DMTF) solvated gallium(III) ion has been determined in solution by means of extended X-ray absorption fine structure (EXAFS) spectroscopy. The gallium(III) ion is four-coordinate in tetrahedral fashion with a mean Ga-S bond distance of 2.233(2) Å in DMTF solution. At the dissolution of indium(III) perchlorate or trifluoromethanesulfonate in DMTF coordinated solvent molecules are partly reduced to sulfide ions, and a tetrameric complex with the composition [In₄S₄(SHN(CH₃)₂)₁₂]⁴⁺ is formed. The structure of the solid tetrameric complex in the perchlorate salt was solved with single crystal X-ray diffraction. Four indium(III) ions and four sulfide ions form a highly symmetric heterocubane structure where each indium binds three bridging sulfide ions and each sulfide ion binds three indium(III) ions with a mean In-S bond distance of 2.584(1) Å, and S-In-S angles of 90.3(1)°. Each indium(III) additionally binds three DMTF molecules at significantly longer mean In-S bond distance, 2.703(1) Å; the S-In-S angles are in the range 80.3-90.4°. Large angle X-ray scattering data on a DMTF solution of indium(III) trifluoromethanesulfonate show that the same tetrameric species characterized in the solid state is also present in solution, whereas the EXAFS measurements only give information about the In-S bond distances due to the short core hole lifetime.