More Than Carbazole Derivative Activates Room Temperature Ultralong Organic Phosphorescence of Benzoindole Derivative

Herein, we report four carbazole/1H-benzo[f]indole (Cz/Bd) derivatives with increasing Bd substitution (Bd number=0~3), which give a general mechanism for Bd-based ultralong organic phosphorescence. To physically isolate Cz and Bd, we synthesized Cz and Bd in the lab, separately. According to experimental results, we draw several important points. The first important point is that Bd and its derivatives commonly possess two groups of intrinsic phosphorescence bands, of which short-lifetime band at ~450 nm is assigned to the molecular phosphorescence of their neutral molecules and of which typical ultralong phosphorescence bands at 560 nm, 610 nm and 660 nm are assigned to their radical cations. Amazingly, PMMA films (1wt.%) of CNCzBdBr and CN2BdBr both demonstrate photo-activated room-temperature ultralong organic phosphorescence while this doesn’t happen to Bd and CN3Bd. The second important point is that activation of ultralong phosphorescence from Bd derivatives involves three factors: well dispersion with limited amount in matrix, generation of Bd derivatives’ radical cations and stabilizing radical cations mediated by matrix. Cz derivative can function as a matrix to activate (room temperature) ultralong organic phosphorescence of Bd derivative but its activation function can be replaced by other methods such as photo-activation. The third important point is that the photo-activated ultralong organic phosphorescence is closely related to molecular structure of Bd derivative and stability of its radical cation. The fourth important point is that for double-carbazole system with trace isomer its room temperature ultralong organic phosphorescence originates at least from synergistic effect of monosubstituted product and disubstituted product of Bd. Furthermore, it is discovered that several other matrixes can also activate room-temperature ultralong organic phosphorescence of Bd derivatives, further verifying the second important point. To our best knowledge, this study is a big breakthrough in ultralong organic phosphorescence and will probably open a new era for its development.

Widening the scope of the corrole sulfonation

The sulfonation reaction has been particularly useful to prepare amphiphilic derivatives of 5,10,15-tris(pentafluorophenyl)corrole, but it has been limited to this corrole. We have studied the scope of this reaction, using 5,10,15-triphenylcorrole as the prototypical example of corrole structure. The reaction protocol has been modified to avoid the corrole aggregation, which limited its reactivity in the neat chlorosulfonic acid. Surprisingly, the reaction shows an unprecedented regioselectivity for corrole derivatives, affording 3 as the main product, but also corrole 5, which is the first example of monosubstituted corrole on pyrrole B. By modulating the corrole:chlorosulfonic acid reagent ratio, it has been possible to obtain the antipodal disubstituted product 6, demonstrating again a not usual regioselectivity for corrole substitution. These results allow the preparation of novel amphiphilic corrole derivatives, which open up their potential applications in different fields.

The regioselective α-alkylation of the benzophenone imine of glycinamide, alaninamide, and related derivatives

The benzophenone imine of glycinamide was alkylated using ion pair extraction (RX, 10% aq. NaOH, Bu4NHSO4 (1 equiv.), CH2Cl2, rt) to give the α-monosubstituted products, which were then alkylated a second time using stronger basic conditions (KO-t-Bu, THF, 0 °C, RX). Crystal structures of the Schiff bases of glycinamide, an α-monosubstituted and an α,α-disubstituted product were reported.Key words: benzophenone imines, Schiff bases, alkylation, ion pair extraction (IPE), phase-transfer catalysis (PTC), anhydrous base, X-ray crystal structures.

Synthesis and reaction chemistry of the heterobimetallic FeIr complexes (CO)3(PPh3)Fe(μ-PCy2)Ir(PPh3)(CO)2 and (CO)4Fe(μ-PCy2)Ir(1,5-COD)

Reactions of Li[Fe(CO)4(PCy2)] with trans-IrCl(CO)(PPh3)2 and [IrCl(1,5-COD)]2 (COD = cyclooctadiene) results in the formation of the μ-PCy2 bridged complexes (CO)3(PPh3)Fe(μ-PCy2)Ir(PPh3)(CO)2, 1, and (CO)4Fe(μ-PCy2)Ir(1,5-COD), 2, respectively. 1 is coordinatively saturated with an FeIr dative bond and does not form an adduct with CO or undergo oxidative addition with H2, HCl, or CH3I. The protonation of 1 with HBF4 gives the Ir hydride compound [(CO)3(PPh3)Fe(μ-PCy2)Ir(H)(PPh3)(CO)][BF4]. 1 undergoes phosphine substitution reactions in which PPh3 is replaced by PR3. Substitution is at Ir for PEt3, PnBu3, PiPr3, PBz3, and PCy3, at Fe for PMe2Ph, and at both metal centers for PPh2Me. The substitution pattern is selective and appears to be sterically controlled. There is also evidence for cooperativity between metal centers in the formation of the PPh2Me adduct since only the disubstituted product can be detected. Coordinative unsaturation was generated at the Ir centre by thermally induced CO loss from (CO)3(PPh3)Fe(μ-PCy2)Ir(PCy3)(CO)2 to give (CO)3(PPh3)Fe(μ-PCy2)Ir(PCy3)(CO). The reaction of 2 with excess CO(g) resulted in the formation of the carbonyl species (CO)4Fe(μ-PCy2)Ir(CO)3. 2 also reacts with 2 PEt3 or DPPE (DPPE = 1,2-bis(diphenylphosphino)ethane) under CO(g) to give the disubstituted products (CO)3(PEt3)Fe(μ-PCy2)Ir(PEt3)(CO)2 and (CO)3Fe(μ-PCy2)(μ-DPPE)Ir(CO)2 with loss of 1,5-COD. Keywords: heterobimetallic FeIr complexes, cooperativity, phosphido-bridge.

Angriff eines lithiierten Aminofluorsilans auf die C-O-Bindung des Cr(CO)6; Bildung von Isonitrilkomplexen/Attack by a Lithiated Aminofluorosilane on the C - O Bond of Cr(CO)6; Formation of Isonitrile Complexes

The photochemical reaction of a lithiated aminofluorosilane with Cr(CO)6 leads to substitution of one or two carbonyl oxygen atoms and formation of isonitrile complexes. The crystal structure of the disubstituted product, cis-di(tert-butylisonitrile) tetracarbonylchromium, has been determined.

Some reactions of 10-substituted-10H-pyrido[3,2-b][1,4]benzothiazine-n-butyllithium adducts with acyl and sulfonyl chlorides

Reaction of 10H-pyrido[3,2-b][1,4]benzothiazines 1 possessing a 10-methyl 1f, 10-(3-dimethylaminopropyl) 1b, or 10-(2-dimethylaminopropyl) 1c substituent, with n-butyllithium and methyl chloroformate or diethyl chlorophosphate affords predominantly 1,2-dihydropyridines 11 and the 4-substituted derivatives 12. The 1,7-disubstituted product 15b was obtained from reaction of the 10-methyl compound 1f with p-fluorobenzoyl chloride. On the other hand, treatment of the 10-methyl analog 1f with trifluoromethanesulfonyl chloride gave the unexpected 4-chloro derivative 12c and 13c which probably arises from the 1-trifluoromethanesulfonyl-1,2-dihydropyridine 11c via elimination of trifluoromethanesulfonic (sulfinic) acid. The N-10 dealkylated product 1a was obtained from reaction of the 10-(1-methyl-2-dimethylaminoethyl) analog 1g with n-butyllithium and methyl chloroformate, whereas a similar reaction employing the 10-(2-dimethylaminoethyl) derivative 1h gave rise to the N-methoxycarbonyl derivative 18. On the other hand, reaction of 1h with n-butyllithium alone gave the N-10 n-hexyl product 19. Mechanisms for the formation of 1a, 11, 12, 13, 15, 16, and 19 are described.

Reactions of titanium(IV) chloride with formic acid

Titanium(IV) chloride reacts with formic acid to give the disubstituted product, Cl2Ti(OOCH)2, at low temperatures and the hydrolysed product (OH)2Ti(OOCH)2 at higher temperatures. These compounds have been characterized by elementary analysis, infrared and thermal measurements. The possibility of these solvolysed products acting as Lewis acids has also been explored.