Interfaces between polycyclic -electron systems and metals play prominent roles in organic or graphene-based (opto)electronic devices, in which performance-related parameters depend critically on the properties of metal/semiconductor contacts. Here, we explore how the topology of the -electron system influences the bonding and the electronic properties of the interface. We use azulene as a model for nonalternant pentagonheptagon (5-7) ring pairs and compare it to its isomer naphthalene, which represents the alternant 6-6 ring pair. Their coverage-dependent interaction with Ag(111) and Cu(111) surfaces was studied with the normal-incidence X-ray standing wave (NIXSW) technique, near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, UV and X-ray photoelectron spectroscopy (UPS, XPS), and density functional theory (DFT). Coveragedependent adsorption heights and spectroscopic data reveal that azulene forms shorter interfacial bonds than naphthalene and engages in stronger electronic interactions with both surfaces. These differences are more pronounced on Cu. Increasing coverages lead to larger adsorption heights, indicating bond weakening by intermolecular repulsion. The extensive DFT calculations include dispersive interactions using: (1) the DFT-D3 scheme, (2) the vdW surf correction based on DFT-TS, (3) a Many-Body Dispersion (MBD) correction scheme, and (4) the D3 surf scheme. All methods predict the adsorption heights reasonably well with an average error below 0.1 Å. The stronger bond of azulene is attributed to its nonalternant topology, which results in a reduced HOMO-LUMO gap and brings the LUMO energetically close to the Fermi energy of the metal, causing stronger hybridization with electronic states of the metal surfaces.

X-ray structure determinations of tetrakis(trifluoromethyl)diphosphane (2c, mp -82 degrees C, triclinic, P&onemacr;; Z = 1, a = 529.7(3) pm, b = 681.6(2) pm, c = 802.8(3) pm, alpha = 108.58(1) degrees, beta = 99.66(1) degrees, gamma = 103.29(1) degrees, wR2 = 0.204) and -diarsane (3c, mp -52 degrees C, monoclinic, P2(1)/c; Z = 2, a = 769.5(3) pm, b = 750.0(3) pm, c = 960.7(2) pm, beta = 105.26(1) degrees, wR2 = 0.115), both at -100(3) degrees C, reveal the molecules to adopt the trans conformation in the solid. Compared with the tetramethyl derivatives, the E-E (224.6(2)/246.3(1) pm, E = P, As) and E-C (188.3(4)/201.3(7) pm) bonds are elongated by 4.5/4.8 pm and 3.4/3.4 pm, respectively. From gas electron diffraction studies of diphosphane 2c a mixture of 85(10)% trans and 15(10)% gauche conformers can be deduced; diarsane 3c shows the trans form exclusively. The molecular parameters (E-E, 224.8(11)/245.2(6); E-C, 189.6(4)/ 201.2(4) pm) agree excellently with those determined for the crystalline state. As a result of quantum chemical calculations at Hartree-Fock and hybrid density functional levels of theory using 6-311+G basis sets, the gauche conformer of hydrazine derivative 1c and the trans conformer of diarsane 3c are clearly lowest in energy. However, for diphosphane 2c the gauche and not the trans form is found to be slightly more stable. Variations of calculated E-E and E-C bond lengths are analyzed and compared with corresponding values of the parent compounds E(2)H(4) (1a to 3a) as well as the tetramethyl derivatives 1b to 3b.

The crystal structure of β-MnF 4 has finally been elucidated. It crystallizes in the non-centrosymmetric space group R3c, no. 161, hR360, with the lattice parameters a = 19.390(3), c = 12.940(3) Å, V = 4213.3(14) Å 3 , Z = 72, T = 100 K. It is a 4a ϫ 4a superstructure of the VF 3 (FeF 3) structure type. The Mn atoms are coordinated octahedron-like by F atoms, of which two are bound terminal, while the other act as μ-bridging F atoms to other Mn atoms forming a threedimensional infinite network structure which can be described by the Niggli formula 3 ϱ [MnF 4/2 F 2/1 ]. Voids on the metal sites, which are oc

Professor Josef Goubeau in memoriamInhaltsu È bersicht. Chlordiphenylstiban (1 d) {P2 1 /c; Z = 4; a = 1191,8(1); b = 853,4(1); c = 1112,0(1) pm; b = 93,60(1)°; ±100 ± 2°C} kristallisiert isotyp zu einer Reihe homologer Verbindungen der Zusammensetzung (H 5 C 6 ) 2 E±X (E = As, X = Cl, Br, I; E = Sb, X = Br, I); der Strukturtyp des Tribenzylstibans (5 d) {Pbca; Z = 8; a = 832,1(2); b = 2681,3(5); c = 1600,9(3) pm; ±100 ± 3°C} ist vom Tribenzylmethanol, -silanol und -silan her bekannt. Demgegenu È ber weist Tribenzyldibromstiboran (6) {P2 1 /n; Z = 4; a = 938,4(2); b = 2292,4(5); c = 1019,7(2) pm; b = 112,71(1)°; ±100 ± 3°C} keine entsprechenden Beziehungen zu bereits bekannten Strukturtypen auf. Charakteristische, gemittelte Bindungsla È ngen und -winkel sind {1 d: Sb±Cl 240,9(1); Sb±C 214,0 pm; Cl±Sb±C 93,8; C±Sb±C 98,6(1)°; 5 d: Sb±C 217,5(3) pm; C±Sb±C 94,9(6)°; 6: Sb±Br 264,6; Sb±C 217,0(8) pm; Br±Sb±Br 179,4(1)°; C±Sb±C 120°; Br±Sb±C 84,8(2)°bis 94,7(2)°}. Beim Stiboran 6 deuten sich sehr schwache intermolekulare Antimon´´Brom-Wechselwirkungen (Sb´´Br 417 pm) an; sie wirken sich jedoch in auffallender Weise auf die Moleku È lkonformation aus. Element±Element Bonds. X. Studies of Chloro(diphenyl)stibane, Tribenzylstibane and Tribenzyldibromostiborane ± Molecular Structures and Isotypism Abstract. Chlorodiphenylstibane (1 d) {P2 1 /c; Z = 4; a = 1191.8(1); b = 853.4(1); c = 1112.0(1) pm; b = 93.60 (1)°; ±100 ± 2°C} crystallizes isotypically with a series of homologous (H 5 C 6 ) 2 E±X compounds (E = As, X = Cl, Br, I; E = Sb, X = Br, I); the structure type of tribenzylstibane (5 d) {Pbca; Z = 8; a = 832.1(2); b = 2681.3(5) pm; c = 1600.9(3); ±100 ± 3°C} is already known from tribenzylmethanol, -silanol and -silane. Tribenzyldibromostiborane (6) {P2 1 /n; Z = 4; a = 938.4(2); b = 2292.4(5); c = 1019.7(2) pm; b = 112.71(1)°; ±100 ± 3°C} does not show an analogous relationship to known structure types. Characteristic mean bond lengths and angles are {1 d, Sb±Cl 240.9(1), Sb±C 214.0 pm, Cl±Sb±C 93.8°, C±Sb±C 98.6(1)°; 5 d, Sb±C 217.5(3) pm, C±Sb±C 94.9(6)°; 6, Sb±Br 264.6; Sb±C 217.0(8) pm, Br±Sb±Br 179.4(1)°; C±Sb±C 120°; Br±Sb±C 84.8(2)°to 94.7(2)°}. Stiborane 6 exhibits very weak intermolecular Sb´´Br interactions of 417 pm which, however, affect the molecular conformation in a striking way.

Herein we present the crystal structure of lithium hexafluoridoplumbate(IV) determined from powder X‐ray diffraction data. The cell parameters are a = 5.01067(3), c = 4.66340(5) Å, V = 101.3969(13) Å3 at T = 293 K. Li2PbF6 is isotypic to Li2ZrF6, space group P31m (no. 162). The measured Raman spectrum is compared with the quantum chemically calculated spectrum. Furthermore, we determined the decomposition temperature of Li2PbF6. We also present the corrected space group and crystal structure for SrPbF6 which was previously reported as P42/mmc (no. 131) and could now be corrected to space group P42/mcm [no. 132, a = 5.21719(3), c = 8.92771(11) Å, V = 243.004(4) Å3, T = 293 K].