2,4-Di-chloro-6-{-[2-(tri-fluoro-meth-yl)phen-yl]carboximido-yl}phenol.

The title compound, CHClFNO, was synthesized by the condensation between tri-fluoro-methyl-aniline and di-chloro-salicyl-aldehyde by nucleophilic addition, forming a hemiaminal, followed by a dehydration to generate an imine. The compound crystallizes in an ortho-rhom-bic ( = 8) space group with a dihedral angle of 44.70 (5)° between the two aromatic rings.

Δ-Bis[()-2-(4-isopropyl-4,5-di-hydro-oxazol-2-yl)phenolato-κ , ](1,10-phenanthroline-κ ,')ruthenium(III) hexa-fluorido-phosphate.

The title compound, [Ru(CHNO)(CHN)]PF crystallizes in the tetra-gonal Sohnke space group 422. The two bidentate chiral salicyloxazoline ligands and the phenanthroline co-ligand coordinate to the central Ru atom through N,O and N,N atom pairs to form bite angles of 89.76 (15) and 79.

(η-Benzene)-chlorido-[()-2-(4-isopropyl-4,5-di-hydro-oxazol-2-yl)phenolato]ruthenium(II).

The title compound, [Ru(CHNO)Cl(η-CH)], exhibits a half-sandwich tripod stand structure and crystallizes in the ortho-rhom-bic space group 222. The arene group is η π-coordinated to the Ru atom with a centroid-to-metal distance of 1.6590 (5) Å, with the ()-2-(4-isopropyl-4,5-di-hydro-oxazol-2-yl)phenolate chelate ligand forming a bite angle of 86.

-Bis[bis-(di-phenyl-phosphan-yl)methane-κ,']di-chlorido-ruthenium(II): a triclinic polymorph.

The title compound, [RuCl(CHP)] or [RuCl(dppm)] (dppm = bis-(di-phenyl-phosphan-yl)methane, CHP) crystallizes as two half-mol-ecules (completed by inversion symmetry) in space group ( = 2), with the Ru atoms occupying inversion centers at 0,0,0 and 1/2, 1/2, 1/2, respectively. The bidentate phosphane ligands occupy equatorial positions while the chlorido ligands complete the distorted octa-hedral coordination spheres at axial positions. The bite angles of the phosphane chelates are similar for the two mol-ecules [(P-Ru-P) = 71.

Chiral-at-Metal Racemization Unraveled for MX (a-chel) by Means of a Computational Analysis of MoO (acnac).

Invited for the cover of this issue are Koop Lammertsma and co-workers at the University of Johannesburg and Vrije Universiteit Amsterdam. The image of the kudu's antlers depicts the isomerization and racemization of the chiral-at-metal complex MoO2(acnac)2 (acnac=β-ketoiminate). Read the full text of the article at 10.

Chiral-at-Metal Racemization Unraveled for MX (a-chel) by means of a Computational Analysis of MoO (acnac).

Octahedral chiral-at-metal complexes MX (a-chel) (a-chel=asymmetric chelate) can rearrange their ligands by four mechanisms known as the Bailar (B), Ray-Dutt (RD), Conte-Hippler (CH), and Dhimba-Muller-Lammertsma (DML) twists. Racemization involves their interconnections, which were computed for MoO (acnac) (acnac=β-ketoiminate) using density functional theory at ωB97x-D with the 6-31G(d,p) and 6-311G(2d,p) basis sets and LANL2DZ for molybdenum. Racemizing the cis(NN) isomer, being the global energy minimum with trans oriented imine groups, is a three step process (DML-CH-DML) that requires 17.

(2,2'-Bipyrid-yl)(η--cymene)iodidoruthenium(II) hexa-fluorido-phosphate.

The title compound, having the mol-ecular formula [RuI(η-CH)(CHN)]PF, crystallizes in the triclinic ( = 2) space group as a half-sandwich complex resembling a three-legged piano stool. Important geometrical parameters include Ru-cymene centroid = 1.6902 (17) Å, Ru-I = 2.

Racemization Pathway for MoO(acac) Favored over Ray-Dutt, Bailar, and Conte-Hippler Twists.

Chiral -MoO(acac) racemizes via four pathways that agree with and extend upon Muetterties' topological analysis for dynamic MX(chel) complexes. Textbook Ray-Dutt and Bailar twists are the least favored with barriers of 27.5 and 28.

Atypical and Asymmetric 1,3-P,N Ligands: Synthesis, Coordination and Catalytic Performance of Cycloiminophosphanes.

Novel seven-membered cyclic imine-based 1,3-P,N ligands were obtained by capturing a Beckmann nitrilium ion intermediate generated in situ from cyclohexanone with benzotriazole, and then displacing it by a secondary phosphane under triflic acid promotion. These "cycloiminophosphanes" possess flexible non-isomerizable tetrahydroazepine rings with a high basicity; this sets them apart from previously reported iminophophanes. The donor strength of the ligands was investigated by using their P-κ - and P,N-κ -tungsten(0) carbonyl complexes, by determining the IR frequency of the trans-CO ligands.

Easy Access to Phosphine-Borane Building Blocks.

In this paper, we highlight the synthesis of a variety of primary phosphine-boranes (RPH ⋅BH ) from the corresponding dichlorophosphines, simply by using Li[BH ] as reductant and provider of the BH protecting group. The method offers facile access not only to alkyl- and arylphosphine-boranes, but also to aminophosphine-boranes (R NPH ⋅BH ) that are convenient building blocks but without the protecting BH moiety thermally labile and notoriously difficult to handle. The borane-protected primary phosphines can be doubly deprotonated using n-butyllithium to provide soluble phosphanediides Li [RP⋅BH ] of which the phenyl-derivative Li [PhP⋅BH ] was structurally characterized in the solid state.

Performance of TDDFT Vertical Excitation Energies of Core-Substituted Naphthalene Diimides.

We have evaluated the performance of various density functionals, covering generalized gradient approximation (GGA), global hybrid (GH) and range-separated hybrid (RSH), using time dependent density functional theory (TDDFT) for computing vertical excitation energies against experimental absorption maximum (λ ) for a set of 10 different core-substituted naphthalene diimides (cNDI) recorded in dichloromethane. The computed excitation in case of GH PBE0 is most accurate while the trend is most systematic with RSH LCY-BLYP compared to λ . We highlight the importance of including solvent effects for optimal agreement with the λ .

Distortion-Controlled Redshift of Organic Dye Molecules.

It is shown, quantum chemically, how structural distortion of an aromatic dye molecule can be leveraged to rationally tune its optoelectronic properties. By using a quantitative Kohn-Sham molecular orbital (KS-MO) approach, in combination with time-dependent DFT (TD-DFT), the influence of various structural and electronic tuning parameters on the HOMO-LUMO gap of a benzenoid model dye have been investigated. These parameters include 1) out-of-plane bending of the aromatic core, 2) bending of the bridge with respect to the core, 3) the nature of the bridge itself, and 4) π-π stacking.

Dual Activation of Aromatic Diels-Alder Reactions.

The unusually fast Diels-Alder reactions of [5]cyclophanes were analyzed by DFT at the BLYP-D3(BJ)/TZ2P level of theory. The computations were guided by an integrated activation-strain and Kohn-Sham molecular orbital analysis. It is revealed why both [5]metacyclophane and [5]paracyclophane exhibit a significant rate enhancement compared to their planar benzene analogue.

Rational design of near-infrared absorbing organic dyes: Controlling the HOMO-LUMO gap using quantitative molecular orbital theory.

Principles are presented for the design of functional near-infrared (NIR) organic dye molecules composed of simple donor (D), spacer (π), and acceptor (A) building blocks in a D-π-A fashion. Quantitative Kohn-Sham molecular orbital analysis enables accurate fine-tuning of the electronic properties of the π-conjugated aromatic cores by effecting their size, including silaaromatics, adding donor and acceptor substituents, and manipulating the D-π-A torsional angle. The trends in HOMO-LUMO gaps of the model dyes correlate with the excitation energies computed with time-dependent density functional theory at CAMY-B3LYP.

Chiral Control in Pentacoordinate Systems: The Case of Organosilicates.

Chirality at the central element of pentacoordinate systems can be controlled with two identical bidentate ligands. In such cases the topological Levi-Desargues graph for all the Berry pseudorotations (BPR, max. 20) reduces to interconnected inner and outer "circles" that represent the dynamic enantiomer pair.

Toward Asymmetric Synthesis of Pentaorganosilicates.

Introducing chiral silicon centers was explored for the asymmetric Rh-catalyzed cyclization of dihydrosilanes to enantiomerically enriched spirosilanes as targets to enable access to enantiostable pentacoordinate silicates. The steric rigidity required in such systems demands the presence of two naphthyl or benzo[b]thiophene groups. The synthetic approach to the expanded spirosilanes extends Takai's method (Kuninobu et al.

Nitrilium ions - synthesis and applications.

Nitrilium ions have been well-established in organic chemistry for many decades, but recent developments show them to be far more versatile than hitherto recognized. They are known as stable salts, can be generated in situ, or are present as transient intermediates. We provide a succinct, but comprehensive review on the synthesis, stability, and reactivity of nitrilium ions as synthons for imines, their use in the synthesis of a large spectrum of heterocycles, and their reactions with transition metal complexes.

Metalate-Mediated Functionalization of P by Trapping Anionic [Cp*Fe(CO)(η-P)] with Lewis Acids.

The development of selective functionalization strategies of white phosphorus (P) is important to avoid the current chlorinated intermediates. The use of transition metals (TMs) could lead to catalytic procedures, but these are severely hampered by the high reactivity and unpredictable nature of the tetrahedron. Herein, we report selective first steps by reacting P with a metal anion [Cp*Fe(CO)] (Cp*=C(CH)), which, in the presence of bulky Lewis acids (LA; B(CF) or BPh), leads to unique TM-substituted LA-stabilized bicyclo[1.

Determination of Controlled Self-Assembly of a Paracrystalline Material by Homology Modelling with Hybrid NMR and TEM.

Controlling complexity, flexibility, and functionality of synthetic and biomimetic materials requires insight into how molecular functionalities can be exploited for steering their packing. A fused NDI-salphen (NDI=naphthalene diimide) prototypic artificial photosynthesis material, DATZnS, is shown to be comprised of a phenazine motif, in which the alignment of electric dipole moments in a P2/c supramolecular scaffold can be modulated with bulky substituents. They can also be switched between parallel stacks of dipoles running antiparallel in the DATZnS-H compared with parallel stacks of dipoles in polar layers running in opposite directions in the DATZnS(3'-NMe) parent compound.

A quantitative analysis of light-driven charge transfer processes using voronoi partitioning of time dependent DFT-derived electron densities.

An analytical method is presented that provides quantitative insight into light-driven electron density rearrangement using the output of standard time-dependent density functional theory (TD-DFT) computations on molecular compounds. Using final and initial electron densities for photochemical processes, the subtraction of summed electron density in each atom-centered Voronoi polyhedron yields the electronic charge difference, Q . This subtractive method can also be used with Bader, Mulliken and Hirshfeld charges.

Functionalization of P through Direct P-C Bond Formation.

Research on chlorine-free conversions of P into organophosphorus compounds (OPCs) has a long track record, but methods that allow desirable, direct P-C bond formations have only recently emerged. These include the use of metal organyls, carbenes, carboradicals, and photochemical approaches. The versatile product scope enables the preparation of both industrially relevant organophosphorus compounds, as well as a broad range of intriguing new compound classes.

Iminophosphanes: Synthesis, Rhodium Complexes, and Ruthenium(II)-Catalyzed Hydration of Nitriles.

Highly stable iminophosphanes, obtained from alkylating nitriles and reaction of the resulting nitrilium ions with secondary phosphanes, were explored as tunable P-monodentate and 1,3-P,N bidentate ligands in rhodium complexes. X-ray crystal structures are reported for both κ and κ complexes with the counterion in one of them being an unusual anionic coordination polymer of silver triflate. The iminophosphane-based ruthenium(II)-catalyzed hydration of benzonitrile in 1,2-dimethoxyethane (180 °C, 3 h) and water (100 °C, 24 h) and under solvent free conditions (180 °C, 3 h) results in all cases in the selective formation of benzamide with yields of up to 96%, thereby outperforming by far the reactions in which the common 2-pyridyldiphenylphosphane is used as the 1,3-P,N ligand.

Probing Zeolite Crystal Architecture and Structural Imperfections using Differently Sized Fluorescent Organic Probe Molecules.

A micro-spectroscopic method has been developed to probe the accessibility of zeolite crystals using a series of fluorescent 4-(4-diethylaminostyryl)-1-methylpyridinium iodide (DAMPI) probes of increasing molecular size. Staining large zeolite crystals with MFI (ZSM-5) topology and subsequent mapping of the resulting fluorescence using confocal fluorescence microscopy reveal differences in structural integrity: the 90° intergrowth sections of MFI crystals are prone to develop structural imperfections, which act as entrance routes for the probes into the zeolite crystal. Polarization-dependent measurements provide evidence for the probe molecule's alignment within the MFI zeolite pore system.

A Hybrid Solid-State NMR and Electron Microscopy Structure-Determination Protocol for Engineering Advanced para-Crystalline Optical Materials.

Hybrid magic-angle spinning (MAS) NMR spectroscopy and TEM were demonstrated for de novo structure determination of para-crystalline materials with a bioinspired fused naphthalene diimide (NDI)-salphen-phenazine prototype light-harvesting compound. Starting from chiral building blocks with C molecular symmetry, the asymmetric unit was determined by MAS NMR spectroscopy, index low-resolution TEM diffraction data, and resolve reflection conditions, and for the first time the ability to determine the space group from reciprocal space data using this hybrid approach was shown. Transfer of molecular C symmetry into P2/c packing symmetry provided a connection across length scales to overcome both lack of long-range order and missing diffraction-phase information.

Selective [3+1] Fragmentations of P by "P" Transfer from a Lewis Acid Stabilized [RP ] Butterfly Anion.

Two [3+1] fragmentations of the Lewis acid stabilized bicyclo[1.1.0]tetraphosphabutanide Li[Mes*P ⋅ BPh ] (Mes*=2,4,6-tBu C H ) are reported.