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Triarylboryl appended perylenediimide (PDI-TAB) is designed and synthesized. The incorporation of triarylboranes (TABs) decreases self-aggregation and increases the solubility of PDI-TAB in common organic solvents. Fluorescence emission colors ranging from red, yellow and green are realized by judiciously modulating the concentration of PDI-TAB in solution. The morphology and dimensions of the self-assemblies formed by PDI-TAB can be controlled by changing the experimental conditions. For example, PDI-TAB forms fibers of finite length when bulk powder is dispersed in methanol; it shows flexible lengthy 1D fibers when dichloromethane solution of PDI-TAB is injected into methanol solvent. PXRD analysis indicates that the molecular organization remains the same in both cases. PDI-TAB functions as a selective fluorogenic sensor for toxic fluoride anions; the sensing mechanism is explained by using theoretical calculations. [ABSTRACT FROM AUTHOR]

We report a series of room temperature phosphorescent compounds 1–6 composed of triarylborane (TAB) and cyclometallated iridium complexes. The optical characteristics such as energy of transition and luminescence quantum yield of these compounds can be conveniently fine-tuned by judiciously varying the cyclometallating ligand and the spacer between boron and iridium centers. Compounds 1–6 exhibit bright phosphorescence with the emission color ranging from green to red under a N2 atmosphere. A maximum quantum yield of 0.95 was observed for complex 2. Complexes 1–6 exhibit a rare type of dual emission from singlet and triplet excited states under ambient conditions. The experimental observations are well supported by the theoretical calculations. [ABSTRACT FROM AUTHOR]

Triarylborane-A2H2 (1) and triarylborane-Zn-A2H2 porphyrins (2) have been synthesized by acid catalyzed condensation of 4-dimesitylboryl-benzaldehyde and dipyrromethane under ambient conditions. Compounds 1 and 2 showed multiple emission bands upon excitation at the triarylborane dominated absorption region (350 nm). Detailed experimental and computational studies show that the multiple emission features of 1 and 2 arise as a result of a partial energy transfer from the donor (triarylborane) to the acceptor (porphyrin) moieties. Compounds 1 and 2 showed very high selectivities towards fluoride ions compared to other competing anions. [ABSTRACT FROM AUTHOR]

Two new dicyanovinyl (DCV) functionalized triarylboranes (Mes2B-π-spacer-DCV, for 1: π-spacer = C6H4, for 2: π-spacer = 2,3,5,6-tetramethyl-phenyl) are reported. The molecular structures of 1 and 2 are similar except for the spacer which connects the boryl and DCV units. This small structural perturbation induces drastic changes in the optical properties of 1 and 2. Compound 2 shows weak dual fluorescence emission in nonpolar solvents and a stronger emission in polar solvents. Compound 1 is weakly fluorescent in polar environments but shows an intense single luminescence peak in less polar environments. Compound 1 exhibits a turn-off fluorescence response for both fluoride and cyanide: in contrast, 2 shows a turn on fluorescence response for both anions with different fluorescence signatures. The NMR titration studies reveal that for compound 2, fluoride binds to the boron centre and cyanide binds to the DCV unit. For compound 1, the fluoride ion binds to the boron center, whereas the CN- binds to both the Ar3B and DCV units. [ABSTRACT FROM AUTHOR]

A facile synthetic route for a new class of organoborane compounds (Mes)2B-arene-acacH and (Mes)2Barene- acacBF2 (Mes = mesityl and arene = C6H4 or C6Me4) is reported. The new dyads exhibit intriguing photophysical properties. A small structural change in spacer connecting the two chromophores leads to fine tuning of photophysical properties. The dyad containing 2,3,5,6-tetramethyl phenyl spacer acts as a selective "turn-on" chemodosimetric sensor for cyanide ion. Steric crowding around the boron centre significantly alters anion binding events. From NMR titration studies it is established that fluoride and cyanide follow different binding mechanisms which lead to intriguing optical properties in the reported probes. [ABSTRACT FROM AUTHOR]

The synthesis and optical properties of four new triarylborane-dipyrromethane (TAB-DPM) conjugates (3a-d) containing dual binding sites (hydrogen bond donor and Lewis acid) have been reported. The new compounds exhibit a selective fluorogenic response towards the F- ion. The NMR titrations show that the anions bind to the TAB-DPM conjugates via the Lewis acidic triarylborane centre in preference to the hydrogen bond donor (dipyrromethane) units. [ABSTRACT FROM AUTHOR]

A series of diboradiferrocenes with different aryl substituents was prepared through reaction of B,B-dichlorodiboradiferrocene 2 with arylcopper and Grignard reagents. The mesityl and pentafluorophenyl derivatives, 3–Mes and 3–Pf, were fully characterized by multinuclear NMR, MALDI-TOF mass spectrometry and X-ray crystallography, and their electronic structure was examined by UV-visible spectroscopy and cyclic voltammetry. A comparison of the data for 3–Mes and 3–Pf with those of the parent compound 3–Ph revealed the importance of electronic and steric effects of the substituents on the electronic structure of the compounds and ultimately the degree of electronic interaction between the two ferrocene moieties. An unusually large redox splitting of ΔE = 703 mV was determined from the cyclic voltammogram of 3–Pf. [ABSTRACT FROM AUTHOR]

The reaction of cyclohexylphosphonic acid (C6H11PO3H2), anhydrous CuCl2 and 2,2′-bipyridine (bpy) in the presence of triethylamine followed by a metathesis reaction with KNO3 afforded [Cu4(µ-Cl)2(µ3-C6H11PO3)2(bpy)4](NO3)2 (1). In an analogous reaction involving Cu(OAc)2·H2O, the complex [Cu4(µ-CH3COO)2(µ3-C6H11PO3)2(2,2′-bpy)4](CH3COO)2 (2) has been isolated. The three-component reaction involving Cu(NO3)2·3H2O, cyclohexylphosphonic acid and 2,2′-bipyridine in the presence of triethylamine afforded the tetranuclear assembly [Cu4(µ-OH)(µ3-C6H11PO3)2(2,2′-bpy)4 (H2O)2](NO3)3 (3). Replacing 2,2′-bipyridine with 1,10-phenanthroline (phen) in the above reaction resulted in [Cu4(µ-OH)(µ3-C6H11PO3)2(phen)4(H2O)2](NO3)3 (4). In all the copper(ii) phosphonates (1–4) the two phosphonate ions bridge the four copper(ii) ions in a capping coordination action. Each phosphonate ion bridges four copper(ii) ions in a µ4, η3 coordination mode or 4.211 of the Harris notation. Variable-temperature magnetic studies on 1–4 reveal that all four complexes exhibit moderately strong intramolecular antiferromagnetic coupling. The DNA cleavage activity of complexes 1–4 is also described. Compounds 1 and 3 were able to completely convert the supercoiled pBR322 DNA form I to nick form II without any co-oxidant. In contrast, 50% conversion occurred with 2 and 40% with 4. In the presence of magnesium monoperoxyphthalate all four compounds achieved rapid conversion of form I to form II. [ABSTRACT FROM AUTHOR]