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Zwitterionic nickel(II) compounds with a borate-containing anionic bidentate phosphine ligand (PBP − ) have been synthesized and some of them crystallographically characterized. The methyl complex, (PBP − )Ni + CH 3 (NCCH 3 ), reacts with H 2 to form an 12-membered macrocycle containing three Ni nuclei and reacts with carbon monoxide (CO) to afford the acetyl complex (PBP − )Ni + COCH 3 (CO). The square planar acetyl complex is stable in solution under 1 atm of CO but undergoes irreversible decomposition under high CO pressure at room temperature. X-Ray crystallographic characterization of a decomposition product revealed fragmentation of the anionic borate under high pressure. (PBP − )Ni + COCH 3 (CO) is an active catalyst for ethylene-CO copolymerization, but its productivity is low likely due to its instability under high CO pressure. [ABSTRACT FROM AUTHOR]

Abstract: In this Letter, we present a synthetic and structural study into bis-imino substituted diiminoisoindolines, which can be synthesized either via CaCl2 mediated reaction of phthalonitrile with primary amines, or via direct reaction of these amines with unsubstituted diiminoisoindoline. The preferred synthesis does depend on the methodology, and in two cases singly substituted adducts were formed. The single crystal X-ray structures show that, with the exception of the bis-naphthyl compound, the anti conformation is preferred, and that the ionizable hydrogen atom resides on an exocyclic nitrogen rather than the central isoindoline nitrogen atom. [Copyright &y& Elsevier]

Diiminoisoindoline (DII) can be modified with primary amines to afford bis-substituted heterocycles. Although the metal binding chemistry of isoindoline-based macrocycles and chelates has been explored, the corresponding chemistry of hydrocarbon substituted diiminoisoindolines remains open. The reaction of the bis(benzylimino)isoindoline with AgNO 3 affords a Ag 6 cluster complexed by four equivalents of ligand. The cluster exhibits a previously unknown argentophilic geometry. The Ag 6 unit forms a compressed hexagon, comprised of two Ag 3 triangles that are linked together to form a parallelogram. The argentophilic interactions range from ~ 2.76 to ~ 3.17 Å. [ABSTRACT FROM AUTHOR]

The new fluorescent chromophore BOPHY can be readily synthesized in two steps from commercially available reagents via the coupling of pyrrole-2-carbox-aldehyde with hydrazine followed by reaction with BF3. The resultant symmetric and dimeric tetracycle is composed of two BF2 units in six-membered chelate rings appended with pyrrole units on the periphery. The quantum yields of fluorescence for the unmodified compound and the tetramethyl variant are near unity, with values of 95 and 92%, respectively, in CH2Cl2. We have probed the electronic structure of this compound via cyclic voltammetry and density functional theory analysis. [ABSTRACT FROM AUTHOR]