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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...

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.

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.

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...

The reaction of the previously known bis(6-diphenylphosphinoacenaphthyl-5-)telluride (6-Ph2P-Ace-5-)2Te (IV) with (CO)5ReCl and (CO)5MnBr proceeded with the liberation of CO and provided fac-(6-Ph2P-Ace-5-)2TeM(X)(CO)3 (fac-1: M = Re, X = Cl, fac-2: M = Mn, X = Br), in which IV acts as bidentate ligand. In solution, fac-1 and fac-2 are engaged in a reversible equilibrium with mer-(6-Ph2P-Ace-5-)2TeM(X)(CO)3 (mer-1: M = Re, X = Cl, mer-2: M = Mn, X = Br). Unlike fac-1, fac-2 is prone to release another equivalent of CO to give (6-Ph2P-Ace-5-)2TeMn(Br)(CO)2 (3), in which IV serves as tridentate ligand.