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Despite having good electronic properties, BODIPY (boron dipyrromethene) and its derivatives attract less research attention towards the development of BODIPY based molecular electronics. Here we have investigated the effect of alkyl chain length attached to BODIPY molecule on its diode and negative differential behaviour. An undecenyl‐BODIPY dye (BODIPY‐C11) was designed, synthesized and deposited on Si (111) surface which was further converted into a bilayer using another BODIPY dye, PM567. Various techniques were used to check the arrangement and thickness of the layers which established that the designed molecule is suitable for compact grafting on Si surface. Electrical behaviour of BODIPY‐C11 monolayer and bilayer showed rectification (rectification ratio=500) and NDR property (peak‐to‐valley ratio=1000), respectively with improved device performances as compared to the electrical characteristics shown by 2,6‐diethyl‐4,4‐difluoro‐1,3,5,7‐tetramethyl‐8‐(4'‐(4"‐penteneoxyphenyl)‐4‐bora‐3a,4a‐diaza‐s‐indecene (BODIPY‐C5) grafted on Si. This study established that the electrical behaviour of BODIPY can be modulated by simply changing the alkyl chain length, which will be useful for the development of BODIPY‐based electronic materials. [ABSTRACT FROM AUTHOR]

Redox active π-conjugated organic molecules have shown the potential to be used as electronic components such as diode and memory elements. Here, we demonstrate that using simple surface chemistry, rectification characteristics can be tuned to reproducible negative differential resistance (NDR) with a very high peak-to-valley ratio (PVR) up to 1000 in 2,6-diethyl-4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indecene (BODIPY) grafted on Si. The change in properties is related to oxidation and reduction of BODIPY, which results in the change in resonant to non-resonant tunneling of electrons under bias. This has been explained by the ab initio molecular-orbital theoretical calculations. [ABSTRACT FROM AUTHOR]

[CuCl2(PPh3)2] reacts with the sodium salt of arylselenolates to yield tetrahedral [CuCl(SeAr)(PPh3)2] ((Ar = Ph, 1a; C5H4N, 1b; C4H(4,6-Me)2N2), 1c). During crystallization, the pyridyl nitrogens of the latter complexes 1b and 1c were protonated. However, the similar reaction with CuCl2·2H2O resulted in the formation of the polymeric complex of composition [Cu(SeAr)2]n (Ar = Ph, 2a; C5H4N, 2b). The latter complex 2b yielded the mono nuclear [CuCl(SeC5H4N)(PPh3)2] (1b) on treatment with excess phosphine. All complexes were characterized by elemental analysis, 1H NMR, IR and mass spectroscopy. The molecular structure of [CuCl(SeC5H4N+H)(PPh3)2] (1b′) was investigated by single crystal X-ray diffraction analysis. The copper(ii) complexes of arylselenolates efficiently catalyzed azide–alkyne cyclo-addition reactions (click reactions) in water to give 1,4-substituted 1,2,3-triazoles in good to moderate yields. [ABSTRACT FROM AUTHOR]

Amongst the various porphyrinoids, octaphyrin has attracted significant attention owing to its diverse syntheses, conformations, and metal-ligation properties. Octaphyrin is a higher homologue of porphyrin and is formed by linking together heterocycles such as pyrrole, furan, thiophene, and selenophene through α-α or α- meso carbon bonds. The planar conformation is mainly achieved through inversion of the heterocyclic units from the center of macrocycle; avoiding meso-bridges; introducing a para-quinodimethane bridge; employing a neo-confusion approach; protonation; and by generating dianionic species. In this Focus Review, recent synthetic advancements in the field of octaphyrins are summarized. The twisted conformation of the octaphyrin binds to two metal ions in a tetracoordinate geometry. The diphosphorus complex of octaphyrin represents the first example of a stable expanded isophlorin. [ABSTRACT FROM AUTHOR]

Bodipy laser dyes are highly efficient but degrade rapidly in solution by reacting with in situ generated singlet oxygen (1O2). To increase the lasing lifetimes of these dyes, we have designed and synthesised two different congeners of the widely studied Pyrromethene 567 (PM567) by substitution at the boron centre and/or at both the boron centre and the meso position. The two new dyes showed high lasing efficiencies with increased photostability. The results of theoretical and pulse radiolysis studies revealed that the substitution at the boron centre reduced the 1O2 generation capacity of these dyes as well as their rate of reaction with 1O2, thereby enhancing their lifetimes even under lasing conditions. [ABSTRACT FROM AUTHOR]

Starting from some meso-methyl Bodipy dyes, the corresponding meso-styryl derivatives were synthesized by regioselective Knoevenagel-type condensation with different aromatic aldehydes. The reactions were driven by the alleviation of the structural strain of the alkyl substituted Bodipys that could override the differential acidities of the methyl protons at the pyrrole ring of the Bodipy moiety., (© 2011 American Chemical Society)