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A tetrameric In(i) organometallic complex supported by bulky, π-donating anionic N-heterocyclic olefin (aNHO) ligands is reported, along with its ambiphilic reactivity.

The Si–H bond in {(F3C)3CO}3SiH is exceptionally strong and short; yet the acidity is comparable to common organic acids. This apparent contradiction will be discussed with the aid of contemporary DFT methods.

The reaction of (5-Ph2P-Ace-6-)Li (I) with InCl3 provided (6-Ph2P-Ace-5-)3In (1), which proved to be a remarkably mild transmetalation reagent. The reaction of 1 with NiCl2, originally aimed to all...

Mesoporous titania thin films backfilled with the conjugated polymer PTB7-Th or the small-molecule PhenTe-BPinPh have been studied as novel materials for hybrid photovoltaics. Together with observed structural changes due to backfilling, volumetric mass density can be excluded in determining factors that influence backfilling efficiency for solar cell applications., Efficient infiltration of a mesoporous titania matrix with conducting organic polymers or small molecules is one key challenge to overcome for hybrid photovoltaic devices. A quantitative analysis of the backfilling efficiency with time-of-flight grazing incidence small-angle neutron scattering (ToF-GISANS) and scanning electron microscopy (SEM) measurements is presented. Differences in the morphology due to the backfilling of mesoporous titania thin films are compared for the macromolecule poly[4,8-bis­(5-(2-ethyl­hexyl)­thio­phen-2-yl)benzo[1,2-b;4,5-b′]di­thio­phene-2,6-diyl-alt-(4-(2-ethyl­hexyl)-3-fluoro­thieno[3,4-b]thio­phene-)-2-carboxyl­ate-2-6-diyl)] (PTB7-Th) and the heavy-element containing small molecule 2-pinacol­boronate-3-phenyl­phen­anthro[9,10-b]telluro­phene (PhenTe-BPinPh). Hence, a 1.7 times higher backfilling efficiency of almost 70% is achieved for the small molecule PhenTe-BPinPh compared with the polymer PTB7-Th despite sharing the same volumetric mass density. The precise characterization of structural changes due to backfilling reveals that the volumetric density of backfilled materials plays a minor role in obtaining good backfilling efficiencies and interfaces with large surface contact.

The new bidentate bisphosphino ligand (5-Ph2P-Ace-6-SiMe2)2 (1) binds rhodium(I) chloride and brings it into close proximity to a strong unpolar σ-Si–Si bond, in which it immediately inserts. In the spirocyclic Rh(III) product of the oxidative addition, (5-Ph2P-Ace-6-SiMe2)2RhCl (2), the two Si atoms are still close enough to engage in weak non-covalent interactions.

The efficient synthesis of highly fluorescent para-biphenyl-substituted benzophospholes via zirconium-mediated metallacycle transfer is reported. A norbornene-appended benzophosphole oxide monomer was found to readily undergo living ring-opening metathesis polymerization with the Grubbs third-generation catalyst to yield either a homopolymer or block copolymers. The resulting block copolymers consisting of lipophilic alkylated- or pinacolboronate-capped comonomers undergo self-assembly into spherical micelles in tetrahydrofuran/hexanes mixtures, as determined by dynamic light scattering and transmission electron microscopy. One hallmark of the benzophosphole-containing polymers is their greatly enhanced emission intensity in solution in relation to their monomers, presumably due to a restriction in molecular motion upon formation of homopolymers or assembled block-copolymer micelles. Evidence for “analyte amplified precipitation” was found, wherein addition of a substoichiometric amount of fluoride to a b...

The crystal interaction density is generally assumed to be a suitable measure of the polarization of a low‐molecular weight ligand inside an enzyme, but this approximation has seldomly been tested and has never been quantified before. In this study, we compare the crystal interaction density and the interaction electrostatic potential for a model compound of loxistatin acid (E64c) with those inside cathepsin B, in solution, and in vacuum. We apply QM/MM calculations and experimental quantum crystallography to show that the crystal interaction density is indeed very similar to the enzyme interaction density. Less than 0.1 e are shifted between these two environments in total. However, this difference has non‐negligible consequences for derived properties., The polarization of a drug molecule in an enzyme environment can be approximated by the polarization of the same molecule in its small‐molecule crystal structure. The degree of similarity is quantified in this study for a model compound of the protease inhibitor loxistatin acid in its interaction with cathepsin B by using interaction densities and interaction electrostatic potentials.

The synthesis and structures of the di- and triorgano antimony compounds (6-Ph2P-Ace-5-)2SbCl (1) and (6-Ph2P-Ace-5-)3Sb (2) are presented along with their use as coordination non-innocent ligands for transition metals, leading to the complexes Cl(6-Ph2P-Ace-5-)2SbCuCl (3), Cl2(6-Ph2P-Ace-5-)2SbPdCl (4), Cl2(6-Ph2P-Ace-5-)2SbPtCl (5) and Cl(6-Ph2P-Ace-5-)3SbRhCl (6). The electronic structures of 1-6 were investigated by DFT computations using a set of topological and surface-based real-space bonding indicators derived from the Atoms-In-Molecules (AIM), Non-Covalent interactions Index (NCI), and Electron Localizability Indicator (ELI-D) methods, unravelling a dative Sb-Cu bond character in 3 and polar-covalent Sb-Pd/Pt/Rh interactions in 4-6.

Transmetallation of Pb(OAc)4 with R2 Hg (1), followed by treatment with HCl in Et2 O, provided RPbCl3 (2), the first kinetically stabilized monoorganolead trihalide that resists reductive elimination under ambient conditions. The kinetic stabilisation relies on an intramolecularly coordinating O-donor substituent (R=6-Ph2 P(O)-Ace-5-). The gram-scale preparation of 2 was key for the synthesis of unsymmetrically substituted diaryllead dichlorides RR'PbCl2 (3 a, R'=Ph; 3 b, R'=4-MeOC6 H4 ; 3 c, R'=4-Me2 NC6 H4 ).

A series of bismuth heterocycles, termed bismoles, were synthesized via the efficient metallacycle transfer (Bi/Zr exchange) involving readily accessible zirconacycles. The luminescence properties of three structurally distinct bismoles were explored in detail via time-integrated and time-resolved photoluminescence spectroscopy using ultrafast laser excitation. Moreover, time-dependent density functional theory computations were used to interpret the nature of fluorescence versus phosphorescence in these bismuth-containing heterocycles and to guide the future preparation of luminescent materials containing heavy inorganic elements. Specifically, orbital character at bismuth within excited states is an important factor for achieving enhanced spin-orbit coupling and to promote phosphorescence. The low aromaticity of the bismole rings was demonstrated by formation of a CuCl π-complex, and the nature of the alkene-CuCl interaction was probed by real-space bonding indicators derived from Atoms-In-Molecules, the Electron Localizability Indicator, and the Non-Covalent Interaction index; such tools are of great value in interpreting nonstandard bonding environments within inorganic compounds.

Invited for the cover of this issue is the group of Jens Beckmann from Bremen University, Germany. The cover image shows two phosphinoboranes mounted on the peri-positions of an acenaphthyl scaffold, in which the phosphorus and boron atoms lead to a regular (top) or a frustrated (bottom) Lewis pair, depending on the substituents on the B atom.

The syntheses of the diaryltelluride 6-Ph2P(O)-Ace-5-TeMes (1O), the tellurenyl(II) chlorides 6-Ph2P(E)-Ace-5-TeCl (2O, E = O; 2S, E = S; 2Se, E = Se), the ditelluroxonium(IV) bis(triflate) [6-Ph2P(O)-Ace-5-TeO]2(O3SCF3)2 (3O), the diaryltellurium(IV) dichloride 6-Ph2P(O)-Ace-5-TeMesCl2 (4O), the diarylhalotelluronium(IV) polyhalides [6-Ph2P(O)-Ace-5-TeMesBr]Br3 (5O) and [6-Ph2P(O)-Ace-5-TeMesI]2I8 (6O), and the aryltellurium(IV) trihalides 6-Ph2P(O)-Ace-5-TeX3 (7O, X = Cl; 8O, X = Br; 9O, X = I) are reported. All compounds have been characterized experimentally by means of multinuclear NMR spectroscopy as well as single-crystal X-ray crystallography. The diverse P–E···Te bonding situations (E = O, S, Se) in the peri region have also been investigated in detail by complementary DFT studies including the calculation of peri interaction energies (α-PIE) as well as topological analyses of the electron and pair densities according to the AIM and ELI-D space-partitioning schemes and evaluation of noncovalent b...

The synthesis of the new ligand bis(6-diphenylphosphinoacenaphth-5-yl)sulfoxide, [6-(Ph2P)-5-Ace-6](2)-SO (1), is presented along with six transition metal complexes thereof, namely,1 center dot MCl (M = Rh, Cu, Ag, Au) and1 center dot MCl2(M = Ni, Pd). Within these novel complexes, close metal-sulfur distances are observed and the nature of the M-S coordination, as well as the response of the(+)S-O(-)bond, are investigated in detail with a set of spectroscopic, crystallographic and real-space bonding indicators.

A proximity enforcing diarylsilane ligand is reported, which gives rise to unusual Si–H···M interactions with the d10 metal ions Cu+ and Ag+ upon complexation. These interactions are studied in detail both experimentally and computationally and can be classified to be weakly agostic in nature for the Si–H···Cu interaction. The Si–H···Ag interaction has more signatures of an electrostatic contact.

A modular route to previously inaccessible classes of ring-fused π-extended heteroacenes bearing the heavy inorganic element tellurium (Te) is presented. These new materials can be viewed as n-doped analogs of molecular graphene subunits that exhibit color tunable visible light phosphorescence in the solid state and in the presence of air. The general mechanism of phosphorescence in these systems was probed experimentally and computationally via time-dependent density functional theory (TD-DFT). The incorporation of Te into π-extended oligoacene frameworks was achieved by an efficient Zr/Te transmetalation protocol; related zirconium-element exchange reactions have been used to prepare both electron-rich and electron-deficient heterocycles containing different elements from throughout the p-block. Therefore, the current study provides a clear path to incorporate inorganic elements into heteroacenes of greater complexity and side group selectivity compared to existing synthetic routes.

International audience; The coupling of the crystallographic refinement technique Hirshfeld atom refinement (HAR) with the recently constructed libraries of extremely localized molecular orbitals (ELMOs) gives rise to the new quantum-crystallographic method HAR-ELMO. This method is significantly faster than HAR but as accurate and precise, especially concerning the free refinement of hydrogen atoms from X-ray diffraction data, so that the first fully quantum-crystallographic refinement of a protein is presented here. However, the promise of HAR-ELMO exceeds large molecules and protein crystallography. In fact, it also renders possible electron-density investigations of heavy elements in small molecules and facilitates the detection and isolation of systematic errors from physical effects.

We introduce a large-scale synthesis of a sterically encumbered N-heterocyclic olefin (NHO) and illustrate the ability of its deprotonated form to act as an anionic four-electron bridging ligand. The resulting multicenter donating ability has been used to link two low oxidation state Ge(II) centers in close proximity, leading to bridging Ge-Cl-Ge and Ge-H-Ge bonding environments supported by Ge2C2 heterocyclic manifolds. Reduction of a dimeric [RGeCl]2 species (R = anionic NHO, [(MeCNDipp)2C═CH]-; Dipp = 2,6-iPr2C6H3) did not give the expected acyclic RGeGeR analogue of an alkyne, but rather ligand migration/disproportionation transpired to yield the known diorganogermylene R2Ge and Ge metal. This process was examined computationally, and the ability of the reported anionic NHO to undergo atom migration chemistry contrasts with what is typically found with bulky monoanionic ligands (such as terphenyl ligands).

The use of bis(6-diphenylphosphinoacenaphth-5-yl)tellurium (6-Ph2P-Ace-5-)2Te (6) as a ligand for complex formation reactions with CuCl and AgCl is reported, giving rise to the formation of 1 : 1 complexes (6-Ph2P-Ace-5-)2Te·CuCl (7) and (6-Ph2P-Ace-5-)2Te·AgCl (8). The reaction of 6 with (tht)AuCl or (CO)AuCl failed to provide the analogous complex (6-Ph2P-Ace-5-)2Te·AuCl (9), but gave the recently reported (6-diphenylphosphinoacenaphth-5-yl)gold dimer (6-Ph2P-Ace-5-Au)2 (10) and (6-diphenylphosphinoacenaphth-5-yl)tellurenyl chloride, (6-Ph2P-Ace-5-Te)Cl (11). The reaction of 6, 7 and 8 with PhICl2 provided diarylchlorotelluronium chloride [(6-Ph2P-Ace-5-)2TeCl]Cl (12). Compounds 7, 8 and 12 were characterized by multinuclear NMR spectroscopy and single-crystal X-ray crystallography. DFT computations of 6, 7, 8, [(6-Ph2P-Ace-5-)2TeCl]+ (12′) and [(8-Me2N-Nap-1-)2TeCl]+ (13′) were carried out including a variety of real-space bonding indicators (RSBI) derived from the Atom-In-Molecules (AIM) and the Electron Localizability Indicator (ELI-D) space partitioning schemes. Furthermore, the non-covalent interaction (NCI) index was applied to examine the nature of the Te–X interactions (X = Cu, Ag, P, N, Cl) and complement the AIM and ELI-D approaches.

The Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged for financial support. The energy decomposition and deformation electron density analyses were carried out within the framework of the Project 14-13-00832 supported by the Russian Science Foundation. The preparation of a series of functionalized peri-substituted acenaphthyl compounds 6-Ph2E-Ace-5-Br (1, E = As; 2, E = Sb), 6-Ph2As-Ace-5-TeMes (3), 5-I-Ace-6-TeMes (4), 6-Ph2Sb-Ace-5-TeMes (5), (6-Ph2P-Ace-5)2Te (6), [6-R2E-Ace-5-Te]X (7, E = P, R = Ph, X = Cl; 8, E = P, R = i-Pr, X = Cl; 9, E = P, R = i-Pr, X = Br; 10, E = P, R = i-Pr, X = I; 11, E = P, R = i-Pr, X = ½ (TeI6); 12, E = P, R = i-Pr, X = I3; 13, E = P, R = Ph, X = O3SCF3; 14, E = As, R = Ph, X = O3SCF3; 15, E = Sb, R = Ph, X = O3SCF3) and [6-PhSb-Ace-5-TeMes]O3SCF3 (16) was reported (Ace = acenaphthyl). The synthesis of 7-15 was either achieved by salt metathesis reaction of 5-i-Pr2P-Ace-6-Li with TeCl2∙TMTU (8), TeBr2∙TMTU (9) and TeI4 (10 + 11) or by the aryl cleavage reaction of 6-R2E-Ace-5-TeMes (E = P, As, Sb; R = Ph, i-Pr) with HgCl2 (7), I2 (12) and HO3SCF3 (13-15). The reaction of 5 with triflic acid gave also rise to the formation of [6-PhSb-Ace-5-TeMes]O3SCF3 (16). All compounds have been characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction. Complementary DFT studies including relaxed potential energy scans (PES) and subsequent topological analysis of the resulting electron and pair densities according to the AIM and ELI-D partitioning schemes are performed for the aryltellurenyl chlorides [6-Ph2P-Ace-5-Te]Cl, [8-Me2N-Nap-1-Te]Cl and [8-Me2P-Nap-1-Te]Cl in the gas phase and in MeCN solution, whereby the Te-Cl distances were systematically varied. The same analyses were carried out for the fully optimized [6-R2E-Ace-5-Te]+ cations (E = P, As, Sb) and compared to those of the previously studied intermolecularly stabilized [R3ETeMes]+ cations (E = P, As, Sb). Postprint

The synthesis and characterization of the 5-diphenylphosphinoacenaphth-6-yl-silanes 5-Ph2P-Ace-6-SiMe2H (1), 5-Ph2P(S)-Ace-6-SiMe2H (1S), 5-Ph2P(Se)-Ace-6-SiMe2H (1Se), and 5-Ph2P-Ace-6-SiMe2Cl (2) as well as of the 5-diphenylphosphinoacenaphth-6-yl-silanols 5-Ph2P-Ace-6-SiMe2OH (3), 5-Ph2P(O)-Ace-6-SiMe2OH (3O), 5-Ph2P(S)-Ace-6-SiMe2OH (3S), and 5-Ph2P(Se)-Ace-6-SiMe2OH (3Se) are reported. Due to steric congestion in the bay area, the substituents in peri-positions are affected by repulsion, out-of-plane deflection, and distortion of the spatial arrangement to various extents. The peri-interaction energy associated with the steric congestion of these and a number of previously known reference compounds was computationally estimated with a set of isodesmic reactions. The organo-H-silanes 1, 1S, and 1Se possess very weak intramolecular hydrogen bridges of the types Si–H···P and Si–H···E═P (E = S, Se), whereas the organosilanols 3O, 3S, and 3Se contain medium-strength hydrogen bonds of the type Si–OH···E═P ...

Hirshfeld atom refinement (HAR) is a novel X-ray structure refinement technique that employs aspherical atomic scattering factors obtained from stockholder partitioning of a theoretically determined tailor-made static electron density. HAR overcomes many of the known limitations of independent atom modelling (IAM), such as too short element–hydrogen distances, r(X—H), or too large atomic displacement parameters (ADPs). This study probes the accuracy and precision of anisotropic hydrogen and non-hydrogen ADPs and of r(X—H) values obtained from HAR. These quantities are compared and found to agree with those obtained from (i) accurate neutron diffraction data measured at the same temperatures as the X-ray data and (ii) multipole modelling (MM), an established alternative method for interpreting X-ray diffraction data with the help of aspherical atomic scattering factors. Results are presented for three chemically different systems: the aromatic hydrocarbon rubrene (orthorhombic 5,6,11,12-tetraphenyltetracene), a co-crystal of zwitterionic betaine, imidazolium cations and picrate anions (BIPa), and the salt potassium hydrogen oxalate (KHOx). The non-hydrogen HAR-ADPs are as accurate and precise as the MM-ADPs. Both show excellent agreement with the neutron-based values and are superior to IAM-ADPs. The anisotropic hydrogen HAR-ADPs show a somewhat larger deviation from neutron-based values than the hydrogen SHADE-ADPs used in MM. Element–hydrogen bond lengths from HAR are in excellent agreement with those obtained from neutron diffraction experiments, although they are somewhat less precise. The residual density contour maps after HAR show fewer features than those after MM. Calculating the static electron density with the def2-TZVP basis set instead of the simpler def2-SVP one does not improve the refinement results significantly. All HARs were performed within the recently introduced HARt option implemented in the Olex2 program. They are easily launched inside its graphical user interface following a conventional IAM.

The authors are thankful to the EPSRC, the EPSRC National Mass Spectrometry Service Centre (NMSSC) Swansea, the School of Chemistry St. Andrews, and EaStCHEM for support. A series of peri-substituted phosphorus-tellurium systems R’Te–Acenap–PR2 (R’ = Ph, p-An, Nap, Mes, Tip; R = iPr, Ph) exhibiting large “through space” spin-spin coupling constants and the “onset” of three-centre four-electron type interactions are presented. The influence of the substituents at the phosphorus and tellurium atoms as well as their behavior upon oxidation (with S, Se) or metal-coordination (Pt, Au) is discussed using NMR spectroscopy, single crystal X-ray diffraction, and advanced DFT studies including NBO, AIM and ELI-D analyses. Postprint

The salt metathesis reaction of ArLi with HgCl2 produced Ar2Hg (1, Ar = 6-Ph2P-Ace-5), which underwent complex formation with d(10)-configurated transition metal chlorides and triflates to give the complexes 1·HgCl2, 1·Hg(O3SCF3)2, 1·AgCl, 1·Ag(O3SCF3), [1·Ag(NCMe)2](O3SCF3), 1·AuCl, and [1·Au](O3SCF3) comprising significant metallophilic interactions between Hg(II) and Hg(II), Ag(I), and Au(I), respectively. The transmetalation reaction of ArSnBu3 with HgCl2 afforded ArHgCl (2) that also forms a complex with additional HgCl2, namely, 2·HgCl2, which however lacks metallophilic interactions. Compounds 2 and 1·HgCl2 possess the same elemental composition and can be interconverted in solution by choice of the solvent. In the presence of tetrahydrothiophene (tht), the complexes 1·AuCl and [1·Au](O3SCF3) underwent rearrangement into the Au(III) cation [cis-Ar2Au](+) ([3](+), which was isolated as Cl(-) and (O3SCF3)(-) salts) and elemental Hg. The reaction of 1·Hg(O3SCF3)2 with ArH produced the complex ArHg(ArH)(O3SCF3) (4). The metallophilic interactions are theoretically analyzed by a set of real-space bonding indicators derived from the atoms-in-molecules (AIM) and electron localizability indicator (ELI) space-partitioning schemes.

Oxidative chlorination of ArSbCl2 (1) with SO2Cl2 provided ArSbCl4 (2), the base hydrolysis of which gave rise to the arylstibonic acid (ArSb)4O6(OH)4 (3) having an adamantane type structure. The intramolecularly coordinating substituent Ar = 6-diphenylphosphinoacenaphth-5-yl- modulates the Lewis acidity of 1-3 and prevents extensive aggregation.

Anisotropic atomic displacement parameters obtained separately from highly accurate X-ray and neutron diffraction data are compared, and it is established that Hirshfeld atom refinement of X-ray data can provide structural parameters that are as accurate as those from neutron data., Hirshfeld atom refinement (HAR) is a novel X-ray structure refinement technique that employs aspherical atomic scattering factors obtained from stockholder partitioning of a theoretically determined tailor-made static electron density. HAR overcomes many of the known limitations of independent atom modelling (IAM), such as too short element–hydrogen distances, r(X—H), or too large atomic displacement parameters (ADPs). This study probes the accuracy and precision of anisotropic hydrogen and non-hydrogen ADPs and of r(X—H) values obtained from HAR. These quantities are compared and found to agree with those obtained from (i) accurate neutron diffraction data measured at the same temperatures as the X-ray data and (ii) multipole modelling (MM), an established alternative method for interpreting X-ray diffraction data with the help of aspherical atomic scattering factors. Results are presented for three chemically different systems: the aromatic hydro­carbon rubrene (orthorhombic 5,6,11,12-tetra­phenyl­tetracene), a co-crystal of zwitterionic betaine, imidazolium cations and picrate anions (BIPa), and the salt potassium hydrogen oxalate (KHOx). The non-hydrogen HAR-ADPs are as accurate and precise as the MM-ADPs. Both show excellent agreement with the neutron-based values and are superior to IAM-ADPs. The anisotropic hydrogen HAR-ADPs show a somewhat larger deviation from neutron-based values than the hydrogen SHADE-ADPs used in MM. Element–hydrogen bond lengths from HAR are in excellent agreement with those obtained from neutron diffraction experiments, although they are somewhat less precise. The residual density contour maps after HAR show fewer features than those after MM. Calculating the static electron density with the def2-TZVP basis set instead of the simpler def2-SVP one does not improve the refinement results significantly. All HARs were performed within the recently introduced HARt option implemented in the Olex2 program. They are easily launched inside its graphical user interface following a conventional IAM.

The second-order nucleophilic substitution (SN 2) reaction at a silicon atom is scrutinized by means of snapshots along a pseudoreaction coordinate. Phosphine and fluoride represent both attacking and leaving groups in the modeled SN 2 reaction. In the experimentally obtained 5-diphenylphosphinoacenaphth-6-yl-dimethylfluorosilane, 1, the phosphine and fluorosilane moieties are forced into immediate proximity through an acenaphthyl scaffold, that is, they exhibit peri interactions that serve as the model of the reactant ion-molecule complex and starting point for a theoretical potential-energy surface (PES) scan. Upon dissociation of fluoride, the experimentally obtained silylphosphonium cation 2 serves as a model of the product and end point of the PES scan. The pseudoreaction pathway is studied using geometric, energetic, spectroscopic, molecular-orbital, and topological real-space bonding indicators. It becomes evident that it is crucial to combine such methods to understand the pseudoreaction because they reveal different aspects based on different sensitivity to dispersive, electrostatic, and polar-covalent contributions to bonding, as shown by the reduced density gradient analysis. For example, atoms-in-molecules theory describes a late topological catastrophe, whereas the electron localizability indicator describes an early concerted reaction and natural resonance theory describes a more gradual change of properties. This case study encourages the use of a well-balanced toolbox equipped with complementary methods to emphasize different aspects of bonding.

Transmetalation reactions of ArLi with ECl3 (E = Al, P, In, Bi) and ArSnBu3 with ECl3 (E = B, Ga, Tl, As, Sb) gave rise to the formation of peri-substituted diphenylphosphinoacenaphthyl–element dichlorides ArECl2 (Ar = 6-Ph2P-Ace-5-), which were characterized by multinuclear NMR spectroscopy and X-ray crystallography. DFT calculations were performed on the compounds at relaxed gas-phase molecular geometries. For the series ArECl2 containing group 13 elements one structure type featuring regular Lewis pairs with short E–P peri distances (E = B, Al, Ga, In, Tl) was observed. For the series ArECl2 containing group 15 elements two structural types with very different peri distances (E = P, As, Sb, Bi) were found. The computed electron and pair densities were topologically analyzed according to the atoms-in-molecules (AIM) and electron localizability indicator (ELI-D) space-partitioning schemes, which facilitates the characterization of the peri interactions and also allows for monitoring minute electronic eff...

The intramolecularly coordinated (6-(diphenylphosphino)acenaphth-5-yl)stannanes ArSnBu3 (1), ArSnPh3 (2), ArSnPh2Cl (3), ArSnPhCl2 (4), ArSnCl3 (5), Ar2SnCl2 (6), ArSnPh2O3SCF3 (7), and ArSnPh2F (8) were synthesized and fully characterized by multinuclear NMR spectroscopy (119Sn, 31P, 19F, 13C, 1H) and X-ray crystallography (Ar = 6-Ph2P-Ace-5-). Due to the different substituents, the Lewis acidities of the Sn atoms of 1–8 vary substantially, which is reflected in the different P–Sn peri distances lying in the range from 2.7032(9) to 3.332(2) A. In MeCN, 7 undergoes electrolytic dissociation into solvated triarylstannyl cations and triflate anions. The gas-phase structures of 2–5, 8, and the triarylstannyl cations ArPh2Sn+ (7a) and [ArPh2Sn·NCMe]+ (7b) were obtained by geometry optimization at the B3PW91/TZ level of theory. A detailed analysis of a set of real-space bonding indicators (RSBI) derived from the electron and pair densities following the atoms in molecules (AIM) and electron localizability indi...

The synthesis and molecular structures of 1-(diphenylphosphino)-8-naphthyldimesitylborane (1) and 5-(diphenylphosphino)-6-acenaphthyldimesitylborane (2) are reported. The experimentally determined P-B peri distances of 2.162(2) and 3.050(3) Å allow 1 and 2 to be classified as regular and frustrated Lewis pairs. The electronic characteristics of the (non)bonding P-B contacts are determined by analysis of a set of real-space bonding indicators (RSBIs) derived from the theoretically calculated electron and pair densities. These densities are analyzed utilizing the atoms-in-molecules (AIM), stockholder, and electron-localizability-indicator (ELI-D) space partitioning schemes. The recently introduced mapping of the electron localizability on the ELI-D basin surfaces is also applied. All RSBIs clearly discriminate the bonding P-B contact in 1 from the nonbonding P-B contact in 2, which is due to the fact that the acenaphthene framework is rather rigid, whereas the naphthyl framework shows sufficient conformational flexibility, allowing shorter peri interations. The results are compared to the previously known prototypical phosphinoborane Ph3PB(C6F5)3, which serves as a reference for a bonding P-B interaction. The most prominent features of the nonbonding P-B contact in 2 are the lack of an AIM bond critical point, the unaffected Hirshfeld surfaces of the P and B atomic fragments, and the negligible penetration of the electron population of the ELI-D lone pair basin of the P atom into the AIM B atomic basin.

The syntheses and full characterizations of the peri-substituted naphthalenes (Nap) and acenaphthenes (Ace) 1-Br-8-(Ph2P)-Nap (1a) and 5-Br-6-(Ph2P)-Ace (1b), as well as their derivatives 1-Br-8-[Ph2P(E)]-Nap [E = CH3+ (counterion I–) (2a); E = O (3a); E = S (4a); E = Se (5a)] and 5-Br-6-[Ph2P(E)]-Ace [E = CH3+ (counterion I–) (2b); E = O (3b); E = S (4b); E = Se (5b)] are reported. In order to quantify the energetic and electronic effects of the peri-interactions, an additional set of molecules, 1c–5c, with the bromine atom and the Ph2P(E) fragment on opposite sides of the naphthalene group was generated, which serves as reference because 1c–5c exhibit negligible peri-interactions. The molecular arrangements of all 15 compounds were optimized at the B3PW91/6-311+G(2df, p) level of theory. The analysis of the peri-interactions was not only based on the inspection of the molecular arrangement and energies alone, but extended to a set of real-space bonding indicators (RSBI). These indicators were derived from theoretically calculated electron densities and pair densities, respectively. Particularly, the stockholder, Atoms-In-Molecules (AIM) and Electron-Localizability-Indicator (ELI-D) space partitioning schemes were used to produce Hirshfeld surfaces (HS), bond topological properties and basins of localized bonding and nonbonding electron pairs. Since 1c–5c are 35–58 kJ·mol–1 lower in energy than their counterparts 1a–5a, the hypothesis of a mainly repulsive peri-interaction in 1a/b–5a/b was confirmed. The shapes and contact patterns of the HSs of atoms and fragments involved in the peri-interactions (Br, P, E = CH3+, O, S, Se) reveal that only in 1a and 1b are peri-interactions exhibited between the bromine and the phosphorus atoms. In all other cases (2a/b–5a/b), the interaction mainly occurs between the bromine atom and the E atom/fragment. According to the bond topological properties and the electron populations within the (non)bonding ELI-D basins, which both are almost unaffected by the Br-P/E peri-interaction, sterical interactions are characterized essentially by geometrical and energetical changes.

The salt metathesis reaction of 1,8-dilithionaphthalene with tributyltin chloride provided 1,8-bis(tributyltin)naphthalene (1) in 41% yield. The transmetallation of 1 with tin tetrachloride gave rise to the formation of 7,7,14,14-tetrachlorodinaphtho[1,8bc:1′,8′-fg][1,5]distannocine (2) in 75% yield. The molecular structure of 2·2 H2O·4 THF was established by single crystal X-ray crystallography.

The previously reported bis(6-diphenylphosphinoacenaphth-5-yl)mercury (1) was used as ligand for the preparation of the copper(I) complexes, 1·CuCl and [1·Cu(NCMe)]BF4, which were characterized by multinuclear NMR spectroscopy and X-ray crystallography. DFT calculations employing topological analysis of the electron and electron pair densities within the AIM and ELI-D space-partitioning schemes revealed significant metallophilic Hg···Cu interactions. Evaluation of noncovalent bonding aspects according to the noncovalent interaction (NCI) index was applied not only for the Cu complexes 1·CuCl and [1·Cu(NCMe)]BF4 but also for the previously reported Ag and Au complexes, namely, [1·MCl] (M = Ag, Au) and [1·M(NCMe)n]+ (M = Ag, n = 2; M = Au, n = 0), and facilitated the assignment of attractive dispersive Hg···M interactions with the Hg···Cu contacts being comparable to the Hg···Ag but weaker than the Hg···Au interactions. The localization of the attractive noncovalent bonding regions increases in the order Cu...

We present a time-dependent quantum mechanical analysis of electronic fluxes during large amplitude vibrations of ethane, ethene and ethyne in the electronic ground state. We find that the number of electrons which participate in the concerted electron-nuclear vibrations decrease from ethane via ethene to ethyne. Different initial conditions and different sets of “observer planes” monitoring the electronic rearrangement are tested to demonstrate the robustness of the results. This counter-intuitive result is due to similar electron distributions of single, double and triple bonds along the carbon–carbon (CC)-axis at equal CC-distances.