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We report a class of compounds in which both PIII−X and PI forms featuring the same ligand are stable and readily cycled with each other. A series of PIII−X (X=Cl, Br, I) dicationic triflate salts supported by benzyl‐ and allyl‐substituted 2,6‐bis(benzimidazole‐2‐yl)pyridine (BZIMPY) ligands is synthesized. Surprisingly, treatment of these with R3PO (R=Et, Oct) results in reduction to BZIMPY‐ligated PI monocationic triflate salts while treatment with Ph3P reduces but also substitutes the compound to produce Ph3P‐BZIMPY‐ligated PI dicationic triflate salts. The mechanisms of these surprising reductions are probed experimentally and rationalized computationally. The PIII−X dications are shown to be strong Lewis acids both experimentally and computationally and to readily behave as X+, PX, and P+ transfer agents in reactions with phosphines, NHCs, and diazabutadienes. The PI mono‐ and dications are shown to be very effective P+ transfer agents when treated similarly. Oxidation from a monocationic PI salt back to the dicationic PIII−X (X=Cl, Br) salt was achieved by treatment with N‐chlorosuccinimide (NCS) or N‐bromosuccinimide (NBS). Full characterization is reported using multinuclear nuclear magnetic resonance spectroscopy, elemental analysis, and single‐crystal X‐ray diffractometry where suitable crystals were isolated. [ABSTRACT FROM AUTHOR]

This study reports on the exploration of the phosphinoboration reaction with several thiosemicarbazones (R5R4NC(S)NR3N=CR1R2). Reactions between either Ph2PBpin (pin = 1,2-O2C2Me4) or Ph2PBcat (cat = 1,2-O2C6H4) with thiosemicarbazones containing a terminal primary or secondary amine afforded boron-containing heterocyclic 1,3,4-thiadiazoline products in excellent yield. The addition of Ph2PBpin to thiosemicarbazones containing an NMe2 group in the terminal position generated novel five-membered heterocycles in moderate yield, which included boron, sulfur, and nitrogen atoms. Heterocyclization of the thiosemicarbazones occurs preferentially in the presence of functional groups such as acetyl and pyridyl groups. [ABSTRACT FROM AUTHOR]

While cyanine dyes enjoy a multitude of uses in science and technology, their phosphorus analogues, phosphamethine cyanine dyes, have not yet found benchtop applications primarily because of their sensitivity to air and moisture. We are excited to report full characterization of an extraordinarily stable acyclic phosphamethine cyanine dye. Nitrile substituents on the N-heterocyclic framework afford air and water stability as well as resistance to methylation and sulfuration even under forcing conditions. Cyclic voltammetry confirms a high oxidation potential of the compound and computational investigations reveal stabilized orbitals. The unusual orbital stability appears to render the normally electron-rich PI site an extremely poor nucleophile and difficult to oxidize. From a practical perspective, this dye is prepared in a one-pot method under mild conditions. [ABSTRACT FROM AUTHOR]

Research has been conducted on 1,2,4-triazol-5-ylidenes. The authors describe the methods developed for the synthesis of these compounds.

The reductive dehalogenation of a zwitterionic GeII species to make a zwitterionic GeI dimer with a 1,2‐dicationic core is reported herein. To the root of the stability of this compound, the molecular and electronic structures were comprehensively characterized and investigated using crystallographic, spectroscopic, and computational methods. It was determined that the Ge centers are attracted because they are both electron‐rich and positively charged. A comparison to the electronic structure in triphosphenium cations revealed varying degrees of covalent bonding and that this difference can be distinguished spectroscopically. [ABSTRACT FROM AUTHOR]

Treatment of two equivalents of the triphosphenium zwitterion L with sources of Ni0 and Pd0 form the mononuclear η2‐diphosphoniodiphosphene complexes 1 and 2. The reaction between L and [FeCp(CO)2]2 results in the binuclear μ‐η1:η1‐diphosphoniodiphosphene iron complex 3, which features an alternative bonding motif of the diphosphoniodiphosphene unit. The formation of these species has been confirmed by spectroscopic methods and single‐crystal X‐ray diffraction analysis, and their electronic structures have been elucidated using computational methods. A diphosphoniodiphosphene is unexpectedly formed by insertion of Ni0, Pd0, and FeI into the P−P bonds of a triphosphenium zwitterion, giving rise to structurally confirmed μ2‐bound monometallic or μ‐η1:η1‐bimetallic species. [ABSTRACT FROM AUTHOR]

A series of complexes with the formulae [(BIMEt3)SnF4−x][OTf]x with x = 1–4 has been synthesized by successive fluoride abstraction from SnF4 with TMSOTf in the presence of the tetradentate nitrogen donor BIMEt3 (tris ((1-ethyl-benzoimidazol-2-yl)methyl)amine). Single crystal X-ray diffraction and heteronuclear NMR spectroscopic analysis provided insight into these new main group cations. Electrospray ionization mass spectrometric analysis on solutions containing the different salts allowed for successful detection of the cations [(BIMEt3)SnF]3+, [(BIMEt3)SnF2]2+ and [(BIMEt3)SnF3]+. [ABSTRACT FROM AUTHOR]

Conformationally flexible cores that generate large free volume when stacked and have an insufficient number of side-chains for filling the lateral space around each core have been proposed as design criteria for discotic liquid crystals that display nematic rather than columnar mesophases. Presented here are 1,3,5-triazines substituted with three thiophene carboxylate ester groups that fulfil these design criteria. Nine derivatives with linear, branched, and chiral ester chains were synthesised and their mesomorphism was studied by polarised optical microscopy, differential scanning calorimetry, and powder x-ray diffraction. Triazines with linear propyl to octyl chains display monotropic nematic discotic mesophases that crystallise within hours or days or when mechanically agitated. Packing structures for the nematic phases are proposed based on the single crystal structure of the ethyl ester. Their unusually slow nucleation and crystal growth can be attributed to the large number of possible low energy conformations that arise from the conformationally flexible core. Incorporation of racemic and chiral branched chains expectedly lowers the melting points of these derivatives but, unexpectedly, enhances nucleation and crystal growth well above the temperature ranges of their hypothetical nematic phases. Chiral nematic discotic mesophases were obtained for binary mixtures of derivatives with chiral branched and linear chains. [ABSTRACT FROM AUTHOR]

Abstract: The phosphorus–sulfur heterocycles 1,2‐thiaphosphetenes and phosphirene sulfides have been prepared, and represent the first structurally characterized derivatives for either class of compound. These strained P−S ring systems are formed by the reaction of a phosphinidene sulfide and alkyne. Using an internal alkyne, only the 3‐membered PV, phosphirene sulfide was produced, whereas a terminal alkyne yielded a mixture of phosphirene sulfide and 1,2‐thiaphosphetene (PIII). Detailed computational analysis revealed that for numerous derivatives of alkynes, the corresponding 4‐membered rings are always more stable than the 3‐membered isomers. The electronic nature of “free” phosphinidene sulfides (R−P=S) is discussed based on computational results. [ABSTRACT FROM AUTHOR]

The transition metal-free addition of phosphinoboronate ester Ph2PBpin (pin = 1,2-O2C2Me4) to heterocumulenes including carbodiimides, isocyanates, isothiocyanates and carbon dioxide has been investigated. The corresponding 1,2-addition products were readily prepared at room temperature without the need of a catalyst or added base. Addition of methanol to the compounds derived from addition of Ph2PBpin to carbodiimides, isocyanates, and isothiocyanates resulted in traditional hydrophosphination products. The methodology developed in this study provides a simple and elegant route for the generation of a wide range of functionalized phosphines. The phosphinoboronate ester Ph2PBpin also selectively and reversibly adds to CO2 at room temperature in a 1,2-manner. [ABSTRACT FROM AUTHOR]