1

8-Naphthalimide derivatives are luminophore compounds that are widely used in various fields of science and technology and exhibit all the necessary optical characteristics for polymer materials.And they are readily available from a synthetic point of view.They have been used as fluorescent brightening agents and fluorescent dyes.Furthermore

in recent years many organic luminophores with highly p-conjugated systems on phenylacetylene-based moieties have been developed quickly.The elongated electronic pathways along p-extended conjugations in these molecules often present a bathochromic shift in the absorption and fluorescence spectra.Because of their intriguing electro-conductive

magnetic and optical properties

these compounds can be used as electrical conductors in LED displays

fluorescence sensors

lasers

etc

.Here

two new 4-phenylethynyl-1

8-Naphthalimide fluorescent compounds which phenylethynyl moietie is conjugated at the 4-position of the naphthalene ring are prepared through Pd(PPh

3

)

2

Cl

2

-catalyzed Sonogashira reaction from 4-bromo-1

8-naphthalimide in ethanol with CuI as co-catalyzer and Ph

3

P as ligand

and their UV/vis absorption and fluorescence emission spectral properties were studied using prepared solutions in DMF.The respective quantum yields were determined using quinine sulphate as the emission standard.Their electroluminescent characteristics were also determined as a dopped device.Reactions were carried out using 5% bis-[triphenylphosphine]palladium dichloride as catalyst and 5% CuI as co-catalyst in ethanol at reflux temperature with triethylamine as base.N-alkyl-4-bromo-1

8-naphthalimides were conveniently prepared by the condensation of 4-bromo-1

8-naphthalimides and primary alkyla-mine in ethanol with good yields.Their structures are characterized using IR

NMR and EA.The absorption-emission spectra and fluorescence quantum yields are determined and the relationships between molecular structure and fluorescence properties are studied.It is shown from the absorption and fluorescent spectra that the compounds present excellent fluorescence properties.The UV/vis absorption and fluorescence spectra of target product in DMF solution are presented.For compound N-butyl-4-phenylethynyl-1

8-naphthalimide

which were unsubstituted at the p-position on the phenylacetylene

the maximum absorption(λ

max

FL

) was in 374

but with a methyl at the p-position on the phenylacetylene

the λ

max

UV

was shift to 380 nm

which caused an obviously hypsochromic shift.For compound N-butyl-4-phenylethynyl-1

8-naphthalimide the maximum emission(λ

max

FL

) was in 446 nm

but with a methyl at the p-position on the phenylacetylene

the λ

max

FL

was shift to 462 nm

presented an obviously red shift.In addition

extending the conjugated chain caused a greater bathochromic effect on the absorption and emission maximum.4-Arylalkynyl-1

8-naphthalimides showed high fluorescence quantum yields.The fluorescence quantum yield Φ

F

was determined using absorption and fluorescence spectra of compounds in DMF at a concentration of 1×10

-6

mol/L.Quinine sulphate

which has a quantum yield of 0.55

was used as the standard.From the result of the test

it can be seen that these compounds have quantum yields between 0.71~0.75.The electroluminescent properties of 4-phenylethynyl-1

8-naphthalimide compounds were also measured through the doped electroluminescent devices which contains 1% 1

8-naphthali-mides and 99% CBP(4

4′-N

N′-dicarbazole-biphenyl)

and their maximum brightness is 2250 cd/m

2

at 22.5 V and 1600 cd/m

2

at 25 V

respectively.From the tested electroluminescent characteristics

it can be expected that 4-arylalkynyl-1

8-naphthalimides have potential applications as electroluminescent devices.