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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]

The chemistry of low-coordinate phosphorus-containing species is an area of intense interest in modern main group chemistry. While typical routes for accessing such species include pyrophoric phosphorus-centered precursors or harsh reducing agents, triphosphenium cations represent a more convenient and safer alternative. This Perspective summarizes the use of air- and moisture-stable triphosphenium salts of [dppeP]+ as a source of P+ ions for the generation of a variety of new and/or useful low-coordinate phosphorus-containing species. These range from phosphorus-rich oligomers to phosphamethine cyanine dyes. Special emphasis is placed on the electronic structure of the newly generated species as well as their subsequent reactivity. [ABSTRACT FROM AUTHOR]

This investigation examines the reactivity of phosphinoboronate esters Ph2PBpin (pin = 1,2-O2C2Me4) and Ph2PBcat (cat = 1,2-O2C6H4), as well as other phosphinoboron species, with various aryl and aliphatic acyl chlorides. These reactions proceed smoothly to give acyl phosphines of the type RC(O)PR′2 along with loss of a boron-chloride compound. In some cases, a second equivalent of the phosphinoboron species can add to the C＝O double bond at elevated temperatures to give the corresponding diphosphines RC(OBR′′2)(PR′2)2. These ambiphilic diphosphines behave like substituted (1,1-bis(diphenylphosphino)methane) derivatives in a reaction of PhC(OBpin)(PPh2)2 (2a) with (η5-C9H7)Rh(η2-coe)2 (coe = cis-cyclooctene) affording the indenyl rhodium complex (η5-C9H7)Rh(PhC(OBpin)(PPh2)2) (3a) where the phosphines are bound to the metal centre in a κ2-P,P bidentate manner. [ABSTRACT FROM AUTHOR]

Treatment of MCl2 (M = Ge or Sn) with 2,6-bis(benzimidazol-2-yl)pyridine (G-BZIMPY, G = NBn, N(3,5-CF3)Bn, NAllyl and O) yielded the self-ionization products [G-BZIMPYMCl][MCl3] (1–6) in high yields (75–98%). Reduction reactions are examined and the nickel complexes 8 and 9 ([(NBn-BZIMPY)2Ni][MCl3]2) are isolated from the reaction of Ni(COD)2 with 1 and 2 respectively. [NBn-BZIMPYSnCl][SnCl3] shows a significantly stronger MLCT band in the UV-vis absorption spectrum than its germanium counterparts, with germanium complexes exhibiting negative solvatochromism that is not observed in tin complexes. [ABSTRACT FROM AUTHOR]

Treatment of GaCl3 with 2,6-bis(benzimidazol-2-yl)pyridine (G-BZIMPY, G = NBz, N(3,5-CF3)Bz, N-allyl and O) yielded the autoionization products [G-BZIMPYGaCl2][GaCl4] (1–4) in great yields. The Ga(iii) complex 1 was reduced to Ga(i) using K2[Fe(CO)4], resulting in the complex [(NBzBZIMPY)(Cl)Ga–Fe(CO)4] (7). GaCl3 and AlCl3 were complexed by the structurally similar bis(imino)pyridine (DIMPY) and the resulting complexes are compared to those of G-BZIMPY. [ABSTRACT FROM AUTHOR]

We present the synthesis of a zwitterionic triphosphenium molecule, tBu(C5H2)(PPh2)2PI (L), which can act as a single- or multidentate ligand with group 6, 7, 8 and 9 metal carbonyl complexes. Group 6, [M(CO)5L] complexes are formed under photolytic conditions, where the metal is bound at the P(i) center. In the case of Mo(CO)6, the bimetallic complex [M(CO)5LMo(CO)3] is generated, which features bonds to both the phosphorus(i) center and the cyclopentadienyl moiety of the molecule. Interestingly, group 7 and 9 metal carbonyl dimers generate bimetallic complexes in the form [M2(CO)nL], where both metal centers are bound at the phosphorus(i) center. A detailed analysis of these molecules is provided, including X-ray diffraction, multinuclear NMR, infrared spectroscopy and computational investigations. [ABSTRACT FROM AUTHOR]

Although salts of thiazolium cations are known, many readily prepared iodide salts have eluded spectroscopic and structural characterization; herein, data for a variety of such salts are reported. It has been demonstrated that thiazolium cations can be deprotonated to generate S,N-heterocyclic carbenes and their “electron rich olefin” dimers, but use of the former has been largely overshadowed by that of the more common N-heterocyclic carbenes. We report herein that the deprotonation of thiazolium iodides and their subsequent reaction with a conveniently prepared triphosphenium precursor grants phosphamethine cyanine cations with solid-state geometry and electronic structure unlike those of NHC-stabilized cations. Protection of the phosphorus atom in such ions with elemental sulfur provides an air- and moisture-stable dithiophosphinium salt. [ABSTRACT FROM AUTHOR]