PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ATOM complex”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources

The geometry of metal-ligand interactions relevant to proteins. II. Angles at the metal atom, additional weak metal-donor interactions.

Geometrical data which could be of relevance in the structure determination, structure refinement, assessment or understanding of metalloproteins have been extracted from the Cambridge Structural Database (CSD). The CSD contains crystallographic data from 'small-molecule' structures determined by X-ray or neutron diffraction to an accuracy and precision much better than that of most current protein structure determinations. Structures of Mg, Mn, Fe, Cu and Zn complexes with ligands whose donor atoms may be only N, O, S or Cl have been selected and analysed in terms of the geometry of the metal coordination group - octahedral, tetrahedral, tetragonal pyramidal etc. The r.m.s. deviation of all the interbond angles around the metal atom provides a measure, delta, of the deviation from ideal geometry. Average values of delta are tabulated for the different metals in each type of complex. For simple non-chelated complexes of Mn, Fe and Zn, distortions of up to 5 degrees in octahedral complexes and 10 degrees in tetrahedral complexes are found to be normal and seem likely to be a consequence of packing effects, ligand bulk or intramolecular effects. Substantially larger distortions are found for some other metals and geometries and are common for chelated complexes. Brief comments on six-, seven- and eight-coordinate Ca complexes are included. Tables are also presented showing that for four- and five-coordinate complexes of Zn and Cu it is quite common to find additional weakly coordinated ligands, usually with N or O donor atoms and with M.N,O distances longer than a normal bond length but shorter than a van der Waals contact, e.g. in the range 2.4-3.0 A for Zn and 2.6-3.0 A for Cu. Although the contributions to bond valency or bonding energy of such interactions may not be great, their effect on geometry can be considerable; they can, for example, cause much larger distortions of tetrahedral Zn complexes than indicated above.

Chelating Agents↗

Structural and electronic effects on the polarographic half-wave potentials of copper (II) chelate complexes.

Polarographic measurements in dimethylformamide solution have been performed on 37 bis-chelate Cu(II) complexes containing primarily salicylaldimine, geta-ketoamine, beta-iminoamine, and pyrrole-2-aldimine ligand systems. The complexes were selected in order to reveal the effect of stereochemical and donor atom variations on half-wave potentials. Mono- and binuclear complexes undergo one-and two-electron reductions, respectively, which were established for representative cases by controlled potential coulometry. The response of Cu(II)/Cu(I) potentials to these variations reveals that nonplanar bis-chelate complexes are easier to reduce than their planar analogs, rigid planar tetradentate or related planar bis-chelate complexes, and complexes differing only in donor atoms are more readily reduced in the order N4 less than N2O2 less than N2S2. Binuclear complexes are reduced in one two-electron or two resolvable one-electron steps depending on ligand structure. Potentials of these and other complexes previously examined are considered in relation to the markedly positive potentials of "blue" copper proteins and ligand structural features which might afford Cu(II)/Cu(I) potentials in the protein range are noted.

Binding Sites↗

Using atomic force microscopy to study nucleosome remodeling on individual nucleosomal arrays in situ.

In eukaryotes, genomic processes like transcription, replication, repair, and recombination typically require alterations in nucleosome structure on specific DNA regions to operate. ATP-dependent nucleosome remodeling complexes provide a major mechanism for carrying out such alterations in vivo. To learn more about the action of these important complexes, we have utilized an atomic force microscopy in situ technique that permits comparison of the same individual molecules before and after activation of a particular process, in this case nucleosome remodeling. This direct approach was used to look for changes induced by the action of the human Swi-Snf remodeling complex on individual, single-copy mouse mammary tumor virus promoter nucleosomal arrays. Using this technique, we detect a variety of changes on remodeling. Many of these changes are larger in scale than suggested from previous studies and involve a number of DNA-mediated events, including a preference for the removal of a complete turn (80 basepairs) of nucleosomal DNA. The latter result raises the possibility of an unanticipated mode of human Swi-Snf interaction with the nucleosome, namely via the 11-nm histone surface.

Adenosine Triphosphate↗

Diastereoisomerism of thiol complexes of arsenic acids and pseudoasymmetry of arsenic: a 1H and 13C NMR study.

Diastereoisomeric complexes of methylphenylarsinic acid and (L)-glutathione could be partially separated by HPLC, but the separated compounds rapidly racemized, presumably by pyramidal inversion at the arsenic atom. Hydrolysis of the diastereoisomeric complexes yielded methylphenylarsinous acid as a pair of enantiomers revealed by a 1H NMR study with an asymmetric lanthanide shift reagent. Methylphenylarsinous acid was also synthesized as an enantiomeric pair, shown by an asymmetric shift reagent experiment, by the hydrolysis of iodomethylphenylarsine. 1H and 13C NMR spectroscopy were used to demonstrate that complexing of phenylarsonic acid with (R,S)-3-mercapto-1,2-propanediol and with (R,S)-1-mercapto-2-propanol yielded, in each case, a pair of enantiomers, PhAs[(R)-ligand)]2, PhAs[(S)-ligand)]2, in which the homomorphic ligands were diastereotopic, and a pair of diastereoisomers, PhAs[(R)-ligand][(S)-ligand], which differed from each other in the configuration about the pseudoasymmetric arsenic atom.

Arsenates↗

A consensus-binding structure for adenine at the atomic level permits searching for the ligand site in a wide spectrum of adenine-containing complexes.

Attempts to derive structural features of ligand-binding sites have traditionally involved seeking commonalities at the residue level. Recently, structural studies have turned to atomic interactions of small molecular fragments to extract common binding-site properties. Here, we explore the use of larger ligand elements to derive a consensus binding structure for the ligand as a whole. We superimposed multiple molecular structures from a nonredundant set of adenosine-5'-triphosphate (ATP) protein complexes, using the adenine moiety as template. Clustered binding-site atoms of compatible atomic classes forming attractive contacts with the adenine probe were extracted. A set of atomic clusters characterizing the adenine binding pocket was then derived. Among the clusters are three vertices representing the interactions of adenine atom N6 with its protein-binding niche. These vertices, together with atom C6 of the purine ring system, complete the set of four vertices for the pyramid-like structure of the N6 anchor atom. Also, the sequence relationship for the adenine-binding loop interacting with the C2-N6 end of the conjugated ring system is expanded to include a third hydrophilic cluster interacting with atom N1. A search procedure involving interatomic distances between cluster centers was formulated and applied to seek putative binding sites in test cases. The results show that a consensus network of clusters, based on an adenine probe and an ATP-complexed training set of proteins, is sufficient to recognize the experimental cavity for adenine in a wide spectrum of ligand-protein complexes.

Adenine↗

SPR studies of carbohydrate-protein interactions: signal enhancement of low-molecular-mass analytes by organoplatinum(II)-labeling.

The relatively insensitive surface plasmon resonance (SPR) signal detection of low-molecular-mass analytes that bind with weak affinity to a protein--for example, carbohydrate-lectin binding--is hampering the use of biosensors in interaction studies. In this investigation, low-molecular-mass carbohydrates have been labeled with an organoplatinum(II) complex of the type [PtCl(NCN-R)]. The attachment of this complex increased the SPR response tremendously and allowed the detection of binding events between monosaccharides and lectins at very low analyte concentrations. The platinum atom inside the organoplatinum(II) complex was shown to be essential for the SPR-signal enhancement. The organoplatinum(II) complex did not influence the specificity of the biological interaction, but both the signal enhancement and the different binding character of labeled compounds when compared with unlabeled ones makes the method unsuitable for the direct calculation of biologically relevant kinetic parameters. However, the labeling procedure is expected to be of high relevance for qualitative binding studies and relative affinity ranking of small molecules (not restricted only to carbohydrates) to receptors, a process of immense interest in pharmaceutical research.

Carbohydrates↗

Interaction of porphine and its metal complexes with C60 fullerene: a DFT study.

We performed DFT calculations (BLYP general-gradient approximation in conjunction with a double numerical basis set) for the interaction of free porphine ligand and a number of its metal complexes with C60 molecule to analyze how the nature of a central metal ion influences the geometry and electronic characteristics (electrostatic potential and spin density distribution and highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) structure). We found that the presence of a central metal ion is crucial for a strong interaction. The energy of interaction between H2P and C60 is -0.3 kcal mol(-1) only, whereas the formation energies for the metal complexes vary from -27.3 kcal mol(-1) for MnClP.C60 to -45.8 kcal mol(-1) for MnP.C60. As a rule, the formation energy correlates with the separations between porphinate and fullerene molecules; the Mn and Fe complexes exhibit the closest approach of ca. 2.2 A between the metal ion and carbon atoms of C60. In most porphine-C60 complexes studied, the two closest contacts of central metal ion or H are those with carbon atoms of the (6,6) bond; VOP.C60 is the only exception, where the closest V...C contacts involve the (5,6) bond. The macrocycle geometry changes, and the magnitude of the effect depends on the central atom, being especially dramatic for Mn, MnCl, and Fe complexes. The shape of LUMOs in most complexes with C60 is not affected notably as compared to the LUMO of the isolated C60 molecule. In the case of Fe, the HOMO extends from the central atom to two opposite pyrrol rings. At the same time, the HOMO-LUMO gap energy decreases drastically in most cases, by ca. 20-30 kcal mol(-1). For electrostatic potential distribution, we systematically observed that the negative lobe contacting C60 shrinks, whereas the opposite one becomes notably bigger. In the case of paramagnetic complexes of VO, Mn, FeCl, Co, and Cu, spin density distribution was analyzed as well.

Journal Article↗

Evidence for a new class of defects in highly n-doped Si: donor-pair-vacancy-interstitial complexes.

Electron channeling experiments performed on individually scanned, single columns of atoms show that in highly n-type Si grown at low temperatures the primary electrically deactivating defect cannot belong to either the widely accepted class of donor-vacancy clusters or a recently proposed class of donor pairs. First-principles calculations suggest a new class of defects consisting of two dopant donor atoms near a displaced Si atom, which forms a vacancy-interstitial pair. These complexes are consistent with the present experimental results, the measured open volume of the defects, the observed electrical activity as a function of dopant concentration, and the enhanced diffusion of impurities in the presence of deactivated dopants.

Journal Article↗

Yttrium and lanthanide diphosphanylamides: syntheses and structures of complexes with one [(Ph2P)2N]- ligand in the coordination sphere.

Treatment of the recently reported potassium salt [K(thf)(n)][N(PPh(2))(2)] (n=1.25, 1.5) with anhydrous yttrium or lanthanide trichlorides in THF leads after crystallization from THF/n-pentane (1:2) to the monosubstituted diphosphanylamide complexes [LnCl(2)[(Ph(2)P)(2)N](thf)(3)] (Ln=Y, Sm, Er, Yb). The single-crystal X-ray structures of these complexes show that the metal atoms are surrounded by seven ligands in a distorted pentagonal bipyramidal arrangement, in which the chlorine atoms are located in the apical positions. The diphosphanylamide ligand is always eta(2)-coordinated through the nitrogen atom and one phosphorus atom. Further reaction of [SmCl(2)[(Ph(2)P)(2)N](thf)(3)] with K(2)C(8)H(8) or reaction of [LnI(eta(8)-C(8)H(8))(thf)(3)] with [K(thf)(n)][N(PPh(2))(2)] in THF gives the corresponding cyclooctatetraene complexes [Ln[(Ph(2)P)(2)N](eta(8)-C(8)H(8))(thf)(2)] (Ln=La, Sm). The single crystals of these compounds contain enantiomerically pure complexes. Both compounds adopt a four-legged piano-stool conformation in the solid state. The structures of the A and the C enantiomers were established by single-crystal X-ray diffraction. The more soluble bistrimethylsilyl cyclooctatetraene complex [Y[(Ph(2)P)(2)N](eta(8)-1,4-(Me(3)Si)(2)C(8)H(6))(thf)(2)] was obtained by transmetallation of Li(2)[1,4-(Me(3)Si)(2)C(8)H(6)] with anhydrous yttrium trichloride in THF followed by the addition of one equivalent of [K(thf)(n)][N(PPh(2))(2)]. The (89)Y NMR signal of the complex is split up into a triplet, supporting other observations that the phosphorus atoms are chemically equivalent in solution and, thus, dynamic behavior of the ligand in solution can be anticipated.

Journal Article↗

Photodissociation of Mg+-XCH3 (X=F, Cl, Br, and I) complexes. I. Electronic spectra and dissociation pathways.

Photodissociation spectra of Mg+-XCH3 (X=F, Cl, Br, and I) complexes have been measured in the ultraviolet region (225-415 nm). Several fragment ions with and without charge transfer (CT), Mg+, XCH3+, MgX+, MgCH3+, CH3+, and X+, were formed by evaporation (intermolecular bond dissociation) and intracluster reaction (intramolecular bond dissociation) via excited electronic states. Branching ratios of these ions were found to depend both on absorption bands and on halogen atoms. The ground states of the complexes were calculated to have geometries in which the Mg atom lies next to X atom of methyl halide molecules. Positive charges of the complexes are confirmed to be almost localized on Mg. Observed absorption bands were assigned to the transitions of the Mg+2P-2S atomic line perturbed by interactions with methyl halide molecules. Branching ratios of fragment ions can be partly explained by the stability of fragment ions and neutral counterparts. From the excited state potential energy curves along the Mg-X bond distance, dissociation reaction after CT was concluded to proceed predissociatively; potential curve crossings between the initially excited states and repulsive CT states may have a crucial role in the formation of CH3+, XCH3+, and X+. In particular, XCH3+ ions were formed via repulsive CT states having a character of electron excitation from Xnp to Mg+3s.

Journal Article↗

Structure of tris(benzothiazole-N)trichlororhodium(III) nitromethane solvate.

mer-[RhCl3(C7H5NS)3].CH3NO2, Mr = 675.87, monoclinic, P21/n, a = 10.915 (2), b = 19.869 (4), c = 12.328 (3) A, beta = 103.13 (7) degrees, V = 2604 (1) A3, Z = 4, Dx = 1.724 g cm-3, lambda(Mo K alpha) = 0.71037 A, mu = 12.15 cm-1, F(000) = 1352, T = 298 K, final R = 0.0297 for 4459 unique observed reflections. The complex was prepared as part of a series of complexes of RhIII with heterocyclic ligands of the type RhL3X3. On the basis of spectral data alone, the assignment of the geometry as mer or fac and the mode of coordination through N or S were ambiguous, so the X-ray structure of the title complex was determined. The Rh is coordinated to three Cl and three N atoms to give an approximately octahedral, meridional complex. The potentially ambidentate benzothiazole coordinates to the metal through the N atom of the thiazole ring. The average Rh--N and Rh--Cl distances are 2.064 (5) and 2.34 (2) A, respectively.

Benzothiazoles↗

Copper(II) complexes encapsulated in human red blood cells.

Copper(II) complexes were encapsulated in human red blood cells in order to test their possible use as antioxidant drugs by virtue of their labile character. ESR spectroscopy was used to verify whether encapsulation in red blood cells leads to the modification of such complexes. With copper(II) complexes bound to dipeptides or tripeptides, an interaction with hemoglobin was found to be present, the hemoglobin having a strong coordinative site formed by four nitrogen donor atoms. Instead, with copper(II) complexes with TAD or PheANN3, which have the greatest stability. ESR spectra always showed the original species. Only the copper(II) complex with GHL gave rise to a complicated behavior, which contained signals from iron(III) species probably coming from oxidative processes. Encapsulation of all copper(II) complexes in erythrocytes caused a slight oxidative stress, compared to the unloaded and to the native cells. However, no significant differences were observed in the major metabolic properties (GSH, glycolytic rate, hexose monophosphate shunt, Ca(2+)-ATPase) of erythrocytes loaded with different copper(II) complexes, with the exception of methemoglobin levels, which were markedly increased in the case of [Cu(GHL)H-1] compared to [Cu(TAD)]. This latter finding suggests that methemoglobin formation can be affected by the type of complex used for encapsulation, depending on the direct interaction of the copper(II) complex with hemoglobin.

Antioxidants↗

Synthesis, characterisation, crystal structures, reactivity, and electrochemistry of ruthenium-nitrido, ruthenium-cobalt-imido and ruthenapyrrolidone carbonyl clusters containing alkyne ligands.

Thermolysis of [Ru3(CO)9(mu3-NOMe)(mu3-eta2-PhC2Ph)] (1) with two equivalents of [Cp*Co(CO)2] in THF afforded four new clusters, brown [Ru5(CO)8(mu-CO)3(eta5-C5Me5)(mu5-N)(mu4-eta2-PhC2Ph)] (2), green [Ru3Co2(CO)7(mu3-CO)(eta5-C5Me5)2(mu3-NH)[mu4-eta8-C6H4-C(H)C(Ph)]] (3), orange [Ru3(CO)7(mu-eta6-C5Me4CH2)[mu-eta3-PhC2(Ph)C(O)N(OMe)]] (4) and pale yellow [Ru2(CO)6[mu-eta3-PhC2(Ph)C(O)N(OMe)]] (5). Cluster 2 is a pentaruthenium mu5-nitrido complex, in which the five metal atoms are arranged in a novel "spiked" square-planar metal skeleton with a quadruply bridging alkyne ligand. The mu5-nitrido N atom exhibits an unusually low frequency chemical shift in its 15N NMR spectrum. Cluster 3 contains a triangular Ru2Co-imido moiety linked to a ruthenium-cobaltocene through the mu4-eta8-C6H4C(H)C(Ph) ligand. Clusters 4 and 5 are both metallapyrrolidone complexes, in which interaction of diphenylacetylene with CO and the NOMe nitrene moiety were observed. In 4, one methyl group of the Cp* ring is activated and interacts with a ruthenium atom. The "distorted" Ru3Co butterfly nitrido complex [Ru3Co(CO)5(eta5-C5Me5)(mu4-N)(mu3-eta2-PhC2Ph)(mu-I)2I] (6) was isolated from the reaction of 1 with [Cp*Co(CO)I2] heated under reflux in THF, in which a Ru-Ru wing edge is missing. Two bridging and one terminal iodides were found to be placed along the two Ru-Ru wing edges and at a hinge Ru atom, respectively. The redox properties of the selected compounds in this study were investigated by using cyclic voltammetry and controlled potential coulometry. 15N magnetic resonance spectroscopy studies were also performed on these clusters.

Journal Article↗

Three-dimensional structure of the complexin/SNARE complex.

During neurotransmitter release, the neuronal SNARE proteins synaptobrevin/VAMP, syntaxin, and SNAP-25 form a four-helix bundle, the SNARE complex, that pulls the synaptic vesicle and plasma membranes together possibly causing membrane fusion. Complexin binds tightly to the SNARE complex and is essential for efficient Ca(2+)-evoked neurotransmitter release. A combined X-ray and TROSY-based NMR study now reveals the atomic structure of the complexin/SNARE complex. Complexin binds in an antiparallel alpha-helical conformation to the groove between the synaptobrevin and syntaxin helices. This interaction stabilizes the interface between these two helices, which bears the repulsive forces between the apposed membranes. These results suggest that complexin stabilizes the fully assembled SNARE complex as a key step that enables the exquisitely high speed of Ca(2+)-evoked neurotransmitter release.

Adaptor Proteins, Vesicular Transport↗

Cyclic polyvanadates incorporating template transition metal cationic species: synthesis and structures of hexavanadate [PdV6O18]4-, octavanadate [Cu2V8O24]4-, and decavanadate [Ni4V10O30(OH)2(H2O)6]4-.

Three types of heteropolyvanadates, [(C2H5)4N]4[PdV6O18] (1), [(C2H5)4N]4[Cu2V8O24] (2), and [(C6H5)4P]4[Ni4V10O30(OH)2(H2O)6] (3), were synthesized through the reaction between the [VO3]- anion and metal template cations of Pd(II), Cu(II), and Ni(II). The X-ray crystal structures of 1 (a = 29.952(4) A, b = 12.911(2) A, and c = 13.678(2) A, orthorhombic, space group Pca2(1) with Z = 4), 2 (a = 13.740(1) A, b = 22.488(2) A, c = 18.505(2) A, and beta= 94.058(2) degrees , monoclinic, space group P2(1)/n with Z = 4), and 3 (a = 12.333(2) A, b = 16.208(4) A, c = 16.516(3) A, alpha = 112.438(3) degrees , beta = 94.735(3) degrees , and gamma = 104.749(3) degrees , triclinic, space group P with Z = 1) demonstrate that the metal cationic species induced cyclic [VO3](n-)n (n = 6, 8, 10) ring formation and the cations are incorporated in the rings themselves. In the metal inclusion products, the cyclic vanadates act as macrocyclic ligands, in which the metal cationic species act as the templates. The cyclic vanadate is composed of tetrahedral VO4 units that share corners and incorporates a metal cationic species in the center of the molecules. The bowl-shaped complex 1 includes a Pd2+ cation that is coordinated by the oxygen donors of a boatlike hexavanadate ring. The diamagnetic complex 1 was characterized via 51V and 17O NMR spectroscopy. Complex 2 involves an octavanadate ring and two Cu2+, which are located on both sides of the mean plane as defined by the eight oxygen atoms that bridge the vanadium atoms. In the case of complex 3, the di-mu-hydroxo-bridged Ni2+ dimer with capped Ni2+ aqua ions is formed by hydrolysis to form the decavanadate ring, in which two of the tetrahedral vanadate units are not bonded to the Ni2+ core but supported by hydrogen bonds through the aqua-ligand in the capped Ni2+ cation. Complexes 1-3 in solution were clearly identified by their characteristic isotope patterns using ESI-MS studies.

Journal Article↗

Striking conformational change suspected within the phosphoribulokinase dimer induced by interaction with GAPDH.

A multitechnique approach was used to study the [glyceraldehyde-3-phosphate dehydrogenase](2 x 4)-[phosphoribulokinase](2 x 2) multienzymatic complex of the alga Chlamydomonas reinhardtii. On the one hand, each component of the complex was compared with known atomic structures of related enzymes or of similar enzymes originating from different organisms. On the other hand, the overall low resolution architecture of the whole complex was studied using cryoelectron microscopy and image processing techniques. The dimers of phosphoribulokinase are suspected to undergo a dramatic change in activity during a cycle of binding and detaching from tetramers of glyceraldehyde-3-phosphate dehydrogenase. This is likely supported by strong structural differences between the modeled phosphoribulokinase dimers and the counterpart in the three-dimensional reconstruction volume of the whole complex obtained from cryoelectron microscope images.

Amino Acid Sequence↗

First-Row Transition-Metal Complexes of the 1-Methoxycyclobutenedionate(1-) Ion.

The synthesis and characterization by single-crystal X-ray crystallography of a series of monomeric first-row transition-metal complexes with the 1-methoxycyclobutenedionate(1-) ligand are described. The isomorphous compounds [M(CH(3)OC(4)O(3))(2)(H(2)O)(4)] (M = Mn, Co, Ni, Zn) are C(2) symmetric and crystallize in the monoclinic space group C2/c. The metal atom in each of these complexes is six-coordinate with two cis 1-methoxycyclobutenedionate(1-) ligands, the methoxy substituent being oriented cis with respect to the ligating oxygen atom. The remaining coordination sites are filled by four aqua ligands. Monomers are linked by O-H.O hydrogen bonds to form arrays of stepped tapes. Hydrolysis of the methoxy group on the ligand occurs during the formation of the copper complex and {[Cu(C(4)O(4))(H(2)O)(2)].0.25H(2)O}(n)() is produced. This complex crystallizes in the tetragonal space group P4/n and has a structure similar to, but differing significantly from, those of a series of 3-dimensional cage squarates which have been reported previously.

Journal Article↗

Synthesis and characterization of rhenium-copper sulfide cluster complexes [(Ph3P)2N][Re3(CuX)(mu3-S)4Cl6(PMe2Ph)3] (X = Cl, Br, I).

The reaction of a trinuclear rhenium sulfide cluster compound Re3S7Cl7 with dimethylphenylphosphine and CuX2 (X = Cl or Br) or CuX (X = Cl, Br, or I) formed tetranuclear cluster complexes [(Ph3P)2N][Re3(CuX)(mu3-S)4Cl6(PMe2Ph)3] (X = Cl, Br, or I). Their solutions have the characteristic intense blue color with visible spectral bands near 600 nm. Single-crystal X-ray structures show that three mu-S atoms in the intermediate trinuclear rhenium complex coordinate to a copper atom, forming elongated tetrahedral structures in which Re-Cu bonding interaction is negligible (Re-Cu distances are 3.50 to approximately 3.54 A as compared with Re-Re distances ranging from 2.69 to 2.81 A).

Journal Article↗