The influence of the axial group on the crystal structures of boron subphthalocyanines.

The crystal structures of 16 boron subphthalocyanines (BsubPcs) with structurally diverse axial groups were analyzed and compared to elucidate the impact of the axial group on the intermolecular π-π interactions, axial-group interactions, axial bond length and BsubPc bowl depth. π-π interactions between the isoindole units of adjacent BsubPc molecules most often involve concave-concave packing, whereas axial-group interactions with adjacent BsubPc molecules tend to favour the convex side of the BsubPc bowl. Furthermore, axial groups that contain O and/or F atoms tend to have significant hydrogen-bonding interactions, while axial groups containing arene site(s) can participate in π-π interactions with the BsubPc bowl, both of which can strongly influence the crystal packing.

Mechanochemical Synthesis of Chromium(III) Complexes Containing Bidentate PN and Tridentate P-NH-P and P-NH-P' Ligands.

Chromium(III) complexes bearing bidentate {NH(CH)PPh: PN, ()-[NH(CHPh)PPh]: P'N} and tridentate [PhP(CH)N(H)(CH)PPh: P-NH-P, ()-(Pr)PCHCHN(H)CH(Ph)CH(Ph)PPh: P-NH-P'] ligands have been synthesized using a mechanochemical approach. The complexes {-[Cr(PN)Cl]Cl (), -[Cr(P'N)Cl]Cl (), -Cr(P-NH-P)Cl (), and -Cr(P-NH-P')Cl ()} were obtained in high yield (95-97%) the grinding of the respective ligands andthe solid Cr(III) ion precursor [CrCl(THF)] with the aid of a pestle and mortar, followed by recrystallization in acetonitrile. The isolated complexes are high spin.

Bulking Up the Bay-Position Substituents Enables Enhanced Selectivity of -Symmetric Boron Subphthalocyanine-Subnaphthalocyanine Hybrids.

The precise synthesis of subporphyrinoid hybrids with π-expanded topologies and unique material properties plays a promising role in the design of functional macrocycles. Easy, selective, and controllable routes to boron subphthalocyanine-subnaphthalocyanine hybrids, Bsub(Pc-Nc)s, are desirable for this purpose yet synthetically challenging due to random mixtures of -, -, and, in some cases, -symmetric compounds that form during traditional statistical mixed cyclotrimerizations. Herein, we addressed this issue by developing a sterically driven mixed cyclotrimerization with enhanced selectivity for the targeted -symmetric hybrid and complete suppression of sterically crowded macrocyclic byproducts.

Iminologous epoxide ring-closure.

The discovery of new reactions enables chemists to attain a better understanding of fundamental chemical reactivity and push the boundaries of organic synthesis. Our understanding and manipulation of high-energy states such as reactive conformations, intermediates, and transition structures contribute to this field. Herein we interrogate epoxide ring-closure by inserting the C[double bond, length as m-dash]N functionality into a well-known precursor to nucleophilic epoxide ring-closure.

Engineering hydrogen bonding to align molecular dipoles in organic solids for efficient second harmonic generation.

Considering nearly infinite design possibilities, organic second harmonic generation (SHG) molecules are believed to have long-term promise. However, because of the tendency to form dipole-antiparallel crystals that lead to zero macroscopic polarization, it is difficult to design a nonlinear optical (NLO) material based on organic molecules. In this manuscript, we report a new molecule motif that can form asymmetric organic solids by controlling the degree of hydrogen bonding through protonation.

Electronic insights into aminoquinoline-based PNN ligands: protonation state dictates geometry while coordination environment dictates N-H acidity and bond strength.

A variety of transition metal complexes bearing aminoquinoline PNH'-R ligands R = Ph (L1H), Cy (L2H) and their amido analogues are reported for rhodium(I) ([Rh(L1H)(PPh)]1 and Rh(L1)(PPh) 2), cobalt(II) (Co(L2)(Cl) 3), and iron(II) ([Fe(L1H)]5, Fe(L1)6, and [Fe(CMe)(L1H)]PF7). The acid-base and redox properties of the amido complexes 2, 6, and their protio parent complexes 1, and 5 permit the determination of the p and bond dissociation free energy (BDFE) of their N-H bonds while the ligand scaffold is coordinated to metal centres of square planar and octahedral geometry, respectively. From relative concentrations obtained by the use of P{H} NMR spectroscopy, a p value of 14 is calculated for rhodium complex 1, 6.

Synthesis, Characterization, and Catalytic Exploration of Mononuclear Mo(VI) Dioxido Complexes of ()-1--2-(4',4'-Dimethyl-2'-oxazolin-2'-yl)-eth-1-en-1-ates.

The coordination chemistry of the title ligands with Mo metal centers was investigated. Thus, the synthesis and characterization (NMR, X-ray diffraction) of four mononuclear formally Mo(6+) complexes of ()-1--2-(4',4'-dimethyl-2'-oxazolin-2'-yl)-eth-1-en-1-ates (L: R = -Ph, -Ph--NO, -Ph--OMe and --Bu), derived from the part enols (LH), is described. The resulting air-stable MoOL complexes (-) exist, as shown by single-crystal X-ray diffraction experiments, in the -dioxido--κ-,-L conformation in the solid state for all four examples.

Rigid Conjugated Diamine Templates for Stable Dion-Jacobson-Type Two-Dimensional Perovskites.

Hybrid organic-inorganic perovskites (HOIPs) have garnered widespread interest, yet stability remains a critical issue that limits their further application. Compared to their three-dimensional (3D) counterparts, two-dimensional (2D)-HOIPs exhibit improved stability. 2D-HOIPs are also appealing because their structural and optical properties can be tuned according to the choice of organic ligand, with monovalent or divalent ligands forming Ruddlesden-Popper (RP) or Dion-Jacobson (DJ)-type 2D perovskites, respectively.

Platinum(II) complex with 4-nitro-N-(pyridin-2-ylmethylidene)aniline: synthesis, characterization, crystal structure and antioxidant activity.

A novel complex has been prepared using the (E)-4-nitro-N-(pyridin-2-ylmethylidene)aniline bidentate Schiff base ligand and PtCl, namely, dichlorido[(E)-4-nitro-N-(pyridin-2-ylmethylidene)aniline-κN,N']platinum(II) acetonitrile hemisolvate, [PtCl(CHNO)]·0.5CHCN, 1. According to the X-ray measurements of the crystal structure, the Pt ion adopts a PtClN square-planar coordination.

Crystal structure of bis-[(,)-1,2-(bi-naph-thyl-phospho-nito)ethane]-dichlorido-iron(II) di-chloro-methane disolvate.

In the title compound (systematic name: bis-{1,2-bis[12,14-dioxa-13-phospha-penta-cyclo-[13.8.0.

A One-Step Preparation of Tetradentate Ligands with Nitrogen and Phosphorus Donors by Reductive Amination and Representative Iron Complexes.

The synthesis and use of the first examples of unsymmetrical, mixed phosphine donor tripodal NPP' ligands N(CHCHPR)(CHCHPPh) are presented. The ligands are synthesized via a convenient, one pot reductive amination using 2-(diphenylphosphino)ethylamine and various substituted phosphonium dimers in order to introduce mixed phosphine donors substituted with P/P', those being Ph/Cy (), Ph/Pr (), Ph/Bu (), Ph/-Tol (), and Ph/-Tol (). Additionally, we have developed the first known synthesis of a symmetrical tripodal NP ligand N(CHCHPBu) using bench safe ammonium acetate as the lone nitrogen source ().

12,15-Dimethyl-8-oxa-tetra-cyclo-[8.8.0.0.0]octa-deca-1(18),2,4,6,11(16),12,14-heptaen-10-ol.

In the title compound, CHO, the pyran ring is in a half-chair conformation. The fused ring system comprising the benzene and cyclo-hexene rings is essentially planar (r.m.

12-Ethyl-6a,10a-di-hydro-5-6-oxachrysene.

In the title compound, CHO, the pyran ring is in a half-chair conformation. The essentially planar naphthalene ring system (r.m.

[(1*,3*,4*)-3-(2-Hy-droxy-benzo-yl)-1,2,3,4-tetra-hydro-1,4-ep-oxy-naphthalen-1-yl]methyl 4-nitro-benzoate.

The relative stereo- and regiochemistry of the racemic title compound, CHNO, were established from the crystal structure. The fused benzene ring forms dihedral angles of 77.3 (1) and 60.

Why Diorganyl Zinc Lewis Acidity Dramatically Increases with Narrowing C-Zn-C Bond Angle.

The Lewis acidity of a metal center is influenced not only by the electronic properties of the bonded ligands but also by the bond angles, which we suggest to be important for zinc diorganyls. Molecular orbital correlation predicts that a narrower C-Zn-C bond angle of the RZn fragment lowers its lowest unoccupied molecular orbital (LUMO) and increases its Lewis acidity, such that it binds added ligands more strongly. Computations on MeZn(bipy) (bipy = 2,2'-bipyridine) yield that, for every 10° of C-Zn-C narrowing close to tetrahedral geometry, the Zn-N distance shortens by 0.

Hydrogen Bond Assisted l to d Conversion of α-Amino Acids.

l to d conversion of unactivated α-amino acids was achieved by solubility-induced diastereomer transformation (SIDT). Ternary complexes of an α-amino acid with 3,5-dichlorosalicylaldehyde and a chiral guanidine (derived from corresponding chiral vicinal diamine) were obtained in good yield as diastereomerically pure imino acid salt complexes and were hydrolysed to obtain enantiopure α-amino acids. A combination of DFT computation, NMR spectroscopy, and crystal structure provide detailed insight into how two types of strong hydrogen bonds assist in rapid epimerization of the complexes that is essential for SIDT.

An iridium complex with an unsupported Ir-Zn bond: di-iodido-(η-penta-methyl-cyclo-penta-dien-yl)bis-(tri-methyl-phosphane)iridiumzinc(-) benzene hemisolvate.

The title compound, [IrZnI(CH)(CHP)]·0.5CH or [Cp*(PMe)Ir]-[ZnI] (Cp* = -CMe) was obtained and characterized as its benzene solvate [Cp*(PMe)Ir]-[ZnI]·0.5CH.

Enantioselective Hydrogenation of Activated Aryl Imines Catalyzed by an Iron(II) P-NH-P' Complex.

Chiral amines are key building blocks in synthetic chemistry with numerous applications in the agricultural and pharmaceutical industries. Asymmetric imine hydrogenation, particularly with iridium catalysts, is well developed. However, imine reduction still remains challenging in the context of replacing such a precious metal with a cheap, nontoxic, and environmentally friendly substitute such as iron.

A molybdenum tris-(di-thiol-ene) complex coordinates to three bound cobalt centers in three different ways.

The synthesis and structural characterization of the mol-ecular compound (μ-benzene-1,2-di-thiol-ato)hexa-carbonyl-bis-(μ-1,1,1,4,4,4-hexafluorobut-2-ene-2,3-dithiolato)tricobaltmolybdenum, [CoMo(CFS)(CHS)(CO)] or Mo(tfd)(bdt)(Co(CO)) (tfd is 1,1,1,4,4,4-hexafluorobut-2-ene-2,3-dithiolate and bdt is benzene-1,2-di-thiol-ate), are reported. The structure of the mol-ecule contains the molybdenum tris-(di-thiol-ene) complex Mo(tfd)(bdt) coordinated as a multidentate ligand to three cobalt dicarbonyl units. Each of the three cobalt centers is relatively close to molybdenum, with Co⋯Mo distances of 2.

Ligand mixed-valence and electrical conductivity in coordination complexes containing a redox-active phenalenol-substituted ligand.

A new redox-active hydrazone ligand bearing a phenalenol group is described (phpl), which produces neutral six-coordinate Fe and Co complexes (1 & 2) with the ligands identified in different oxidation states; an open-shell anion radical and closed-shell dianion. An intense and very low-energy intervalence charge transfer (IVCT) band is identified in solid-state and in solution in the complexes. Single crystals of 1 are semiconducting (at 300 K, σ = 3.

Synthesis and characterisation of κ-,-oxazoline-enolate complexes of nickel(ii): explorations in coordination chemistry and metal-mediated polymerisation.

The synthesis and characterisation (UV-Vis, IR, X-ray diffraction, ) of a series of Ni(ii) complexes derived from both known and novel 2-acylmethyl-2-oxazolines (2a-g: , ()-1-R-2-(4,4'-dimethyl-2'-oxazolin-2'-yl)eth-1-en-1-ol; R = -Ph, -2-furanyl, --NO-Ph, --Bu, -2-thiofuranyl, -NC-Ph, -CF) is reported. These Ni materials (3a-g) represent the first group 10 metal complexes of this ligand class. All derivatives reported are paramagnetic ( = 1) compounds of formulae Ni(κ-,-L) where L represents an enolate of structure ()-1-R-2-(4',4'-dimethyl-2'-oxazolin-2'-yl)eth-1-en-1-ate formed proton loss from 2.

PNN' & PNN' ligands via reductive amination with phosphine aldehydes: synthesis and base-metal coordination chemistry.

Novel PNN' & P2NN' ligands based on 2-aminopyridine (APyPNN-R) R = Ph (1a), Cy (1b), iBu (1c), 8-aminoquinoline (AQPNN-R) R = Ph (2a), Cy (2b), iBu (2c), iPr (2d), and 2-picolylamine (P2NN-R) R = Ph (3a), Cy (3b), iBu (3c), have been synthesized via a versatile, one-pot, single-step, reductive amination of tertiary phosphine acetaldehydes with the amine by reaction with STAB (where STAB is sodium(triacetoxy)borohydride). Ligands 1b and 1c bridge between paramagnetic Co(ii) and form dimeric complexes Co2Cl4(APyPNN-R)2 (4 and 5) when reacted with cobalt dichloride. Ligands 2a-c coordinate in a tridentate fashion forming chelate complexes MCl2(AQPNN-R) M = Co(ii) (6-8), and, for 2d, the Fe(ii) complex FeCl2(AQPNN-iPr) (9).