Trigonal Prismatic Coordination Research Articles

Trigonal prismatic coordination geometry imparted by a macrocyclic ligand: an approach to large axial magnetic anisotropy for Co(II).

Large uniaxial magnetic anisotropy, expressed by a negative value of the axial zero-field splitting parameter D, has been achieved in a series of trigonal prismatic Co(II) complexes with the general formula [Co(L)X]Y, where L = 1,5,13,17,22-pentaazatricyclo[15.2.2.17,11]docosa-7,9,11(22)-triene, X = Cl-(1a,b), Br-(2), N3-(3), NCO-(4), NCS-(5), NCSe-(6), and Y = Cl-(1), Br-(2), NCS-(4), NCSe-(5), ClO4-(3,6). Complexes 1-6 are six-coordinate with the distorted trigonal prismatic geometry imparted by the pentadentate pyridine-/piperazine-based macrocyclic ligand L and by one monovalent coligand X-. Based on magnetic studies, all complexes 1-6 exhibit strong magnetic anisotropy with negative D-values ranging from about -20 to -41 cm-1. This variation in D (i.e. the increase of magnetic anisotropy) parallels the trend obtained by theoretical calculations and the lesser distortion of the coordination sphere with respect to the trigonal prismatic reference geometry. AC magnetic susceptibility investigations revealed field-induced single-molecule magnet behaviour for all complexes except Cl- derivative 1. The series investigated represents a rare example of Co(II) complexes with a robust trigonal prismatic geometry.

Ideal trigonal prismatic coordination geometry of Co(II) in a honeycomb MOF with a triptycene-based ligand.

A metal-organic framework (MOF) comprised of cobalt ions and triptycene-based 3-fold symmetric bridging ligands 9,10-[1,2]benzenoanthracene-2,3,6,7,14,15(9H,10H)-hexaone (o-TT) was prepared. Single-crystal structure analysis revealed a 2D honeycomb network structure and the ideal trigonal prismatic geometry of the Co(II) ion. The magnetic anisotropy of the Co(II) ion in the trigonal prism coordination geometry was analyzed via magnetic measurements and model calculations.

CRYSTAL STRUCTURE OF THE NEW GERMANIDE Pr3Co2Ge7.36

The structure of Pr3Co2Ge7.36 (Cmmm, a = 4.236 (1), b = 25.994(5), c = 4.272(1) Å, Z = 2) can be considered as a partly disordered derivative of the La3Co2Sn7 type. The Ge positions in the Pr4Ge8 cuboctahedra of the AuCu3-type slabs are conveniently described by two partly occupied sites, one of which is split. The Co and Ge atoms are characterized by square-antiprismatic, cubooctahedral, and trigonal-prismatic coordination.

Crystalline Phase Effects on the Nonlinear Optical Response of MoS2 and WS2 Nanosheets: Implications for Photonic and Optoelectronic Applications

In the present work, some MoS2 and WS2 nanosheets were prepared and characterized. Depending on the preparation procedures, trigonal prismatic (2H) or octahedral (1T) coordination of the metal atoms was obtained, exhibiting metallic (1T) or semiconducting (2H) character. Both MoS2 and WS2 nanosheets were found exhibiting large nonlinear optical (NLO) responses, strongly dependent on their metallic (1T) or semiconducting (2H) character. Therefore, the semiconducting character of MoS2 and WS2 exhibits positive nonlinear absorption and strong self-focusing behavior, while their metallic character counterparts exhibit strong negative nonlinear absorption and important self-defocusing behavior. In addition, the semiconducting MoS2 and WS2 were found exhibiting important and very broadband optical limiting (OL) action extending from 450 to 1750 nm. Therefore, by selecting the crystalline phase of the nanosheets, that is, their semiconduction/metallic character, their NLO response can be greatly modulated. The results of the present work demonstrate unambiguously that the control of the crystalline phase of MoS2 and WS2 provides an efficient strategy for 2D nanostructures with custom-made NLO properties for specific optoelectronic and photonic applications such as OL, saturable absorption, and optical switching.

Enhancing the Luminescence of Eu(III) Complexes with the Ruthenocene Organometallic Unit as Ancillary Ligand.

Five novel Eu(III)-β-diketonate complexes containing ruthenocene ancillary ligands (1,1'-bis(diphenylphosphoryl)ruthenocene─RcBPO) were synthesized and characterized. The coordination compounds presented the general formula [Eu(β-dik)3(RcBPO)], where β-dik stands for 2-thenoyltrifluoroacetonate (tta), 3-benzoyl-1,1,1-trifluoroacetone (btf), 2-dibenzoylmethanate (dbm), 2-acetyl-1,3-indandionate (aind), and 2-benzoyl-1,3-indandionate (bind), and RcBPO stands for 1,1'-bis(diphenylphosphoryl)ruthenocene. The [Eu(aind)3(RcBPO)] complex crystallizes in a monoclinic Cc non-centrosymmetric space group with the europium site environment, assuming a bicapped trigonal prism coordination polyhedron with the symmetry point group close to C2v. Photoluminescent properties for the solid-state samples were described in terms of excitation, emission, lifetime decay curves, and intrinsic and overall quantum yields. The replacement of the two coordinated H2O molecules by the RcBPO ancillary ligand leads to great enhancements of the overall quantum yields (QEuL), with the minimum increment by a factor of 5 for the case of [Eu(btf)3(RcBPO)] and the maximum enhancement of 270 times for the case of the [Eu(dbm)3(RcBPO)] complex. In addition, theoretical calculations were carried out to model the spectroscopic properties of the investigated compounds. To obtain theoretical Judd-Ofelt parameters (Ωλ, λ = 2, 4, and 6) and intramolecular energy transfer rates, the JOYSpectra web platform was employed using the structure obtained from density functional theory calculations. Hence, a rate equation model provided theoretical overall quantum yields, which are in great agreement with measured data.

In Situ Surface-Sensitive Investigation of Multiple Carbon Phases on Fe(110) in the Fischer-Tropsch Synthesis.

Carbide formation on iron-based catalysts is an integral and, arguably, the most important part of the Fischer–Tropsch synthesis process, converting CO and H2 into synthetic fuels and numerous valuable chemicals. Here, we report an in situ surface-sensitive study of the effect of pressure, temperature, time, and gas feed composition on the growth dynamics of two distinct iron–carbon phases with the octahedral and trigonal prismatic coordination of carbon sites on an Fe(110) single crystal acting as a model catalyst. Using a combination of state-of-the-art X-ray photoelectron spectroscopy at an unprecedentedly high pressure, high-energy surface X-ray diffraction, mass spectrometry, and theoretical calculations, we reveal the details of iron surface carburization and product formation under semirealistic conditions. We provide a detailed insight into the state of the catalyst’s surface in relation to the reaction.

Phase transition and formation of inorganic fullerene type nanostructure in WS2 nanosheet system under laser excitation

Here in, laser power and energy dependant chemical and structural changes in WS2 nanosheets have been reported. The nanosheets were obtained through liquid phase exfoliation in N-methyl pyrrolidone (NMP). Simultaneous laser irradiation and Raman spectral analysis were performed on the nanosheets. It was observed that laser power enhancement leads to further exfoliation and red shift of prominent phonon modes E12g and A1g in the nanosheets. Oxidation of the nanosheets was also witnessed with a minimum 50 mJ of laser irradiation. Raman spectral analysis also reveals the transition of WS2 from 2H (hexagonal symmetry, one layer per repeat, trigonal prismatic coordination to 1T (tetragonal symmetry, one layer per repeat, octahedral coordination) crystallographic arrangements with a minimum 50 mJ of laser energy. Formation of incipient inorganic fullerene type nanostructures was also confirmed in the laser irradiated WS2 nanosheets. It is anticipated that such experimental findings will boost further laser induced treatment of transition metal dichalcogenides for novel applications.

An investigation into the coordination chemistry of tripodal “click” triazole ligands with Mn, Ni, Co and Zn ions

The steric influences of the triazole side chains in two tripodal chelating ligands tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) and tris[(1-phenyl-1H-1,2,3-triazol-4-yl)methyl]amine (TPTA) are explored through structural studies of four new mononuclear d-block metal complexes. The manganese(II) complex [Mn(TPTA)2](ClO4)2·H2O 1 includes two TPTA ligands each coordinated in a tridentate fashion to give an unusual trigonal prismatic coordination geometry with two non-coordinated pendant triazole groups which engage in weak hydrogen bonding interactions. [Ni(TBTA)(OH2)Cl]Cl·3H2O·MeCN 2 contains an octahedral nickel(II) centre bound by a tetradentate TBTA ligand along with aqua and chloride ligands, where the significant degree of lattice solvation leads to an extensive hydrogen bonding network linking complexes through hexa-aqua water clusters. The mononuclear copper(II) complex [Cu(TPTA)Cl2]·MeCN 3 contains no classical hydrogen bond donors but instead intermolecular aggregation takes place through chelating CH···Cl hydrogen bonds involving the acidic triazole CH groups which leads to close association of adjacent complexes. The zinc complex [Zn(TPTA)Cl]2[ZnCl4]·MeOH 4, in which cationic [Zn(TPTA)Cl]+ species are accompanied by tetrachlorozincate anions, exhibits a tris-triazole chelating coordination geometry for the TPTA ligand and associates through tetrameric π···π stacking interactions despite the positive charge present on each species. Structural analysis of these complexes, supported by solution-state mass spectrometry, NMR spectroscopic and magnetic susceptibility measurements, where applicable, provides new insights into the breadth of coordination geometries and intermolecular packing modes available to this important class of chelating ligand.

Nanotubes from the Misfit Layered Compound (SmS)1.19TaS2: Atomic Structure, Charge Transfer, and Electrical Properties.

Misfit layered compounds (MLCs) MX-TX2, where M, T = metal atoms and X = S, Se, or Te, and their nanotubes are of significant interest due to their rich chemistry and unique quasi-1D structure. In particular, LnX-TX2 (Ln = rare-earth atom) constitute a relatively large family of MLCs, from which nanotubes have been synthesized. The properties of MLCs can be tuned by the chemical and structural interplay between LnX and TX2 sublayers and alloying of each of the Ln, T, and X elements. In order to engineer them to gain desirable performance, a detailed understanding of their complex structure is indispensable. MLC nanotubes are a relative newcomer and offer new opportunities. In particular, like WS2 nanotubes before, the confinement of the free carriers in these quasi-1D nanostructures and their chiral nature offer intriguing physical behavior. High-resolution transmission electron microscopy in conjunction with a focused ion beam are engaged to study SmS-TaS2 nanotubes and their cross-sections at the atomic scale. The atomic resolution images distinctly reveal that Ta is in trigonal prismatic coordination with S atoms in a hexagonal structure. Furthermore, the position of the sulfur atoms in both the SmS and the TaS2 sublattices is revealed. X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and X-ray absorption spectroscopy are carried out. These analyses conclude that charge transfer from the Sm to the Ta atoms leads to filling of the Ta 5dz2 level, which is confirmed by density functional theory (DFT) calculations. Transport measurements show that the nanotubes are semimetallic with resistivities in the range of 10–4 Ω·cm at room temperature, and magnetic susceptibility measurements show a superconducting transition at 4 K.

The unexpected crystal structure of thallium(I) tricyanomethanide Tl[C(CN)3

Abstract A metathesis reaction employing Ag[C(CN)3] and TlBr yielded the expected target compound Tl[C(CN)3] from aqueous solution, but after its structural and Raman-spectroscopic characterization, it became clear rather unexpectedly, that the title compound does not crystallize isotypically to any of the heavy alkali-metal tricyanomethanides. Tl[C(CN)3] adopts the space group R32 with the trigonal cell parameters a = 806.03(6) and c = 709.86(5) pm exhibiting a crystal structure still related to the one of the also trigonally crystallizing compounds A[C(CN)3] (A = Rb and Cs; space group: R 3 ‾ c $R\overline{3}c$ ) with doubled c-axes, which display distorted octahedrally coordinated A + cations. In Tl[C(CN)3], the Tl+ cations show a trigonal-prismatic coordination sphere with the terminal nitrogen atoms of six tricyanomethanide anions. There is also a long-distance capping of the triangular faces by two tricyanomethanide anions with their central carbon atoms at longer distance (d(Tl–N) = 299 pm; d(Tl⋯C) = 355 pm). Due to these bonding patterns, the tricyanomethanide unit in Tl[C(CN)3] is found to have the smallest volume increment of all [C(CN)3]– anions reported so far. A synopsis of the crystal structures and Raman spectra of all reported tricyanomethanides A[C(CN)3] with monocations (A = Li–Cs, Cu, Ag and Tl) is given. According to quantum-chemical calculations, the central carbon atom within the Y-aromatic π-electron system of the [C(CN)3]– anion and the lone pair at the Tl+ cation are assembled to a one-dimensional string along [001] via Kramers-Anderson super-exchange with equidistant atoms (d(Tl⋯C) = 355 pm), which might be addressed as an undistorted Peierls chain.

Dynamic optimization of guest binding in a library of diastereomeric heteroleptic coordination cages

<h2>Summary</h2> Biological receptors, such as enzymes, are highly flexible and alter their conformation to fit target substrates. Synthetic supramolecular hosts, such as coordination cages, also exhibit some ability to adapt their cavity shape and size in response to guest molecules due to the dynamic nature of the linkages that hold them together. Here, we report the preparation of a new trigonal-prismatic coordination cage that forms selectively, incorporating two different ligands. The cage exhibits up to four diastereomeric configurations, differing in the "portrait" or "landscape" orientation of tetratopic pyrene-based ligands on its rectangular faces. Three diastereomeric forms of the cage have been structurally characterized, and NMR spectroscopy confirmed the formation of a mixture of diastereomers in solution. Although the cage panels are rigid, the different orientations that each panel can adopt enable the cage cavity to dynamically adapt to optimize the binding of guests, including elongated adamantane derivatives and toxic organochlorine pesticides.

Hexadentate technetium-99m bis(thiosemicarbazonato) complexes: synthesis, characterisation and biodistribution.

The syntheses of non-oxido/non-nitrido bis(thiosemicarbazonato)technetium(V) complexes featuring a series of alkyl and ether substituents is presented. The bis(thiosemicarbazones) were radiolabelled with technetium-99m using an optimised one-pot synthesis from [99mTc][TcO4]-. Mass spectrometry and computational chemistry data suggested a distorted trigonal prismatic coordination environment for the bis(thiosemicarbazonato)technetium(V) complexes by way of a bis(thiosemicarbazone)technetium(V)-oxido intermediate complex. The lipophilicities of the complexes were estimated using distribution ratios and three of the new complexes were investigated in mice using kinetic planar imaging and ex vivo biodistribution experiments and were compared to [99mTc][TcO4]-. Modification of the technetium complexes with various lipophilic functional groups altered the biodistributions of the complexes in mice despite evidence suggesting limited stability of the complexes to biologically relevant conditions. The most hydrophilic complex had higher uptake in the kidneys compared to the most lipophilic, which had higher liver uptake, suggesting modification of the excretion pathways.

A Dicobalt(II) Single-Molecule Magnet via a Well-Designed Dual-Capping Tetrazine Radical Ligand

The recent years have witnessed the glory development for the construction of high-performance mononuclear single molecule magnets (SMMs) within a specific coordination geometry, which, however, is not well applied in cluster-based SMMs due to the synthetic challenges. Given that the monocobalt(II) complexes within a trigonal-prismatic (TPR) coordination geometry have been classified as excellent SMMs with huge axial anisotropy (D ≈ -100 cm-1), here we designed and synthesized a new dual-capping tetrazine ligand, 3,6-bis(6-(di(1H-pyrazol-1-yl)methyl)pyridin-2-yl)-1,2,4,5-tetrazine (bpptz), and prepared a novel dicobalt(II) complex, [Cp2CoIII][{(hfac)CoII}2(bpptz•-)][hfac]2·2Et2O (1, hfac = hexafluoroacetylacetonate). In the structure of 1, the bpptz•- radical ligand enwraps two Co(II) centers within quasi-TPR geometries, which are further bridged by the tetrazine radical in the trans mode. The magnetic study revealed that the interaction between the Co centers and the tetrazine radical is strongly antiferromagnetic with a coupling constant (J) of -65.8 cm-1 (in the -2J formalism). Remarkably, 1 exhibited the typical SMM behavior with an effective energy barrier of 69 cm-1 under a 1.5 kOe dc field, among the largest for polynuclear transition metal SMMs. In addition, DFT and ab initio calculations suggested that the presence of a strong Co(II)-radical magnetic interaction effectively quenches the QTM effect and enhances the barrier height for the magnetization reversal.

Trigonal Prismatic Coordination of Discrete Rare Earth Ions, Enforced by the Polyoxotungstate [P4 W27 O99 (H2 O)]16.

A family of solution‐stable polyanions [Na⊂{LnIII(H2O)}{WVIO(H2O)}PV 4WVI 26O98]12− (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) represent the first examples of polyoxometalates comprising a single lanthanide(III) or yttrium(III) ion in a rare trigonal prismatic O6 environment. Their synthesis exploits the reactivity of the organophosphonate‐functionalized precursor [P4W24O92(C6H5PVO)2]16− with heterometal ions and yields hydrated potassium or mixed lithium/potassium salts of composition K x Ln y H12–x–y [Na⊂{Ln(H2O)}{WO(H2O)}P4W26O98]⋅nH2O⋅mLiCl (x=8.5–11; y=0–2; n=24–34; m=0–1.5). The Dy, Ho, Er and Yb derivatives are characterized by slow magnetization relaxation.

The germanides APtGe2 (A = Ca, Sr, Eu)

Abstract The germanides APtGe2 (A = Ca, Sr, Eu) were synthesized from the elements in sealed tantalum ampoules in an induction furnace followed by annealing. The polycrystalline samples were characterized by powder X-ray diffraction (Guinier patterns). The structures of CaPtGe2 (CeRhSn2 type, Cmcm, a = 443.45(3), b = 1593.03(12), c = 886.15(6) pm, wR = 0.0464, 673 F 2 values, 30 variables) and EuPt1.043(5)Ge1.957(5) (CeNiSi2 type, Cmcm, a = 445.23(4), b = 1752.5(2), c = 429.63(4) pm, wR = 0.0415, 389 F 2 values, 19 variables) were refined from single crystal X-ray diffractometer data. One of the germanium site in EuPt1.043(5)Ge1.957(5) showed a small Ge/Pt mixed occupancy. SrPtGe2 (a = 451.13(6), b = 1764.8(2), c = 429.60(5) pm) is isotypic with EuPtGe2. The platinum atoms in both germanides have trigonal prismatic coordination: Pt@Ca4Ge2 and Pt@Eu4Ge2. The germanium substructures differ significantly: Ge2 dumb-bells with 246 and 262 pm Ge–Ge distances in CaPtGe2 versus germanium zig-zag chains (253 pm Ge–Ge distances) and a distorted square net (309 pm Ge–Ge distances) in EuPtGe2. CaPtGe2 and SrPtGe2 are diamagnetic. EuPtGe2 is a Curie–Weiss paramagnet with an experimental magnetic moment of 7.88(1) µB Eu atom−1. The purely divalent character of europium is manifested by a single signal at δ = −11.38(1) mm s−1 in the 151Eu Mössbauer spectrum at 78 K. EuPtGe2 orders antiferromagnetically at T N = 5.4(1) K.

Incommensurately modulated crystal structure of α'(O'3)-type sodium cobalt oxide NaxCoO2 (x ∼ 0.78).

A single-phase sample of α' (O'3)-type layered sodium cobalt oxide NaxCoO2 (x ∼ 0.78) was prepared and its incommensurately modulated crystal structure was analyzed using the (3+1)-dimensional superspace approach to the powder neutron diffraction data. The crystal structure of the cobaltate is accurately described based on the superspace group C2/m(α0γ)00, wherein the positions of Na atoms are most significantly modulated in the monoclinic a direction to form an ordered arrangement. Such a displacive modulation causes a quasi-periodic shift of Na atoms from the centers of the NaO6 polyhedra between undulated CoO2 sheets, changing the form of the NaO6 polyhedron from an octahedral coordination (O) to a trigonal prismatic (P) one, via an intermediate capped trigonal prismatic NaO7 coordination (C). At the positions where the Na atoms are most significantly shifted, the neighboring Na atoms are located at almost touching distances. However, the occupation factor of Na atoms becomes zero at such positions, yielding Na-deficient sites VNa, sandwiched either between C and P, or C and C-type polyhedra.

X-ray diffraction and theoretical study of the transition 2H-3R polytypes in Nb1+xSe2 (0 &lt; x &lt; 0.1)

Single crystals of 2H and 3R niobium diselenide were grown by a chemical transport reaction. The current determinations by single crystals X-ray diffraction reveal a non-stoichiometric composition. The structures are built from Se—Nb—Se slabs with Nb in trigonal prismatic coordination whereas the extra or additional Nb atoms are located in the octahedral holes between the slabs giving rise to the formula 2H and 3R-Nb1+xSe2 with 0.07 &lt; x &lt; 0.118. In particular, vacancy and Nb-Nb interactions may play an important role on the non-stoichiometry and the stacking mode in NbSe2. By increasing the number of additional Nb atoms in the pure 2H-NbSe2, a transition 2H to 3R polytype should occur in order to minimize the Nblayer—Nbextra—Nblayer repulsions between these adjacent slabs. The theoretical study shows that both 2H and 3R-Nb1+xSe2 are thermodynamically stable in the range 0 &lt; x &lt; 0.1.

The system ErNiAl–ZrNiAl at 600 °С and the high-temperature high-pressure modification of ErNiAl

A series of samples along the line ErNiAl–ZrNiAl was synthesized by arc-melting, and annealed at 600 °C or at 1400 °C / 8 GPa. Phase and structural analyses were performed based on X-ray powder diffraction data collected at room temperature on a diffractometer STOE Stadi P (Cu K α 1 radiation, angular range 6° ≤ 2 θ ≤ 110°, scan step 0.015°). The structures were refined by the Rietveld method, using the program DBWS. The formation of limited solid solutions Er 1-0.79(4) Zr 0-0.21(4) NiAl and Zr 1-0.77(3) Er 0-0.23(3) NiAl, which both crystallize with ZrNiAl-type structures, was observed. It was found that high-temperature high-pressure annealing of the three-component (ErNiAl) and four-component (Er 2 ZrNi 3 Al 3 ) samples caused a transformation from the low-temperature modification of the compound ErNiAl with ZrNiAl-type structure to its high-temperature high-pressure modification with MgZn 2 -type structure. The latter showed low solubility of Zr (Er 0.91(3) Zr 0.09(3) NiAl). The structure of ht-hp ErNiAl (MgZn 2 -type) belongs to the family of Friauf-Laves phases: the coordination polyhedra of the Er atoms are 16-vertex Friauf polyhedra, and those of the Ni and Al atoms are 12-vertex icosahedra. The structure of the solid solutions Er 1- x Zr x NiAl and Zr 1- x Er x NiAl (ZrNiAl-type structure) belongs to the family of structures with trigonal prismatic coordination of the smallest atoms (Ni). The structures of the investigated compounds contain similar nets of atoms, in particular nets of triangles and pentagons. They are characterized by high packing coefficients (space filling), which reach 82 %. The highest value was observed for the compound ErNiAl in the sample annealed at 1400 °C / 8 GPa. It may be noted that high pressures generally increase the density, whereas high temperatures have the opposite effect. Key words : aluminide, X-ray powder diffraction, solid solution, crystal structure.

Crystal structure of K3EuSi2O7

As part of research on the flux technique for growing alkali rare-earth elements (REE) containing silicates, tripotassium europium disilicate, K3EuSi2O7, was synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in the space group P63/mcm. In the crystal structure of the title compound, one part of the Eu cations are in a slightly distorted octahedral coordination and the other part are in an ideal trigonal prismatic coordination environment. The disilicate Si2O7 groups connect four EuO6 octahedra and one EuO6 trigonal prism. Three differently coordinated potassium cations are located between them. Silicates containing the larger rare earth elements usually crystallize in a structure that contains the rare-earth cation in both a slightly distorted octahedral and an ideal trigonal prismatic coordination environment.

Site-Specific Structure at Multiple Length Scales in Kagome Quantum Spin Liquid Candidates.

Realizing a quantum spin liquid (QSL) ground state in a real material is a leading issue in condensed matter physics research. In this pursuit, it is crucial to fully characterize the structure and influence of defects, as these can significantly affect the fragile QSL physics. Here, we perform a variety of cutting-edge synchrotron X-ray scattering and spectroscopy techniques, and we advance new methodologies for site-specific diffraction and L-edge Zn absorption spectroscopy. The experimental results along with our first-principles calculations address outstanding questions about the local and long-range structures of the two leading kagome QSL candidates, Zn-substituted barlowite (Cu3Zn x Cu1-x (OH)6FBr) and herbertsmithite (Cu3Zn(OH)6Cl2). On all length scales probed, there is no evidence that Zn substitutes onto the kagome layers, thereby preserving the QSL physics of the kagome lattice. Our calculations show that antisite disorder is not energetically favorable and is even less favorable in Zn-barlowite compared to herbertsmithite. Site-specific X-ray diffraction measurements of Zn-barlowite reveal that Cu2+ and Zn2+ selectively occupy distinct interlayer sites, in contrast to herbertsmithite. Using the first measured Zn L-edge inelastic X-ray absorption spectra combined with calculations, we discover a systematic correlation between the loss of inversion symmetry from pseudo-octahedral (herbertsmithite) to trigonal prismatic coordination (Zn-barlowite) with the emergence of a new peak. Overall, our measurements suggest that Zn-barlowite has structural advantages over herbertsmithite that make its magnetic properties closer to an ideal QSL candidate: its kagome layers are highly resistant to nonmagnetic defects while the interlayers can accommodate a higher amount of Zn substitution.