WO2002086015A2

WO2002086015A2 - Mixed metal organic complexes

Info

Publication number: WO2002086015A2
Application number: PCT/GB2002/001839
Authority: WO
Inventors: Poopathy Kathirgamanathan; Chamila Wickramsinghe; Subramaniam Ganeshamurugan; Seenivasagam Ravichandran
Original assignee: Elam-T Limited
Priority date: 2001-04-20
Filing date: 2002-04-22
Publication date: 2002-10-31
Also published as: GB0109758D0; WO2002086015A3; TW574389B; AU2002251312A1

Abstract

Novel electroluminescent complexes are of formula (Lα)nM1M2 of or formula (Lα)n M1 M2 (Lp), where Lp is a neutral ligand and where M1 is a rare earth, transition metal, lanthanide or an actinide, M2 is a non rare earth metal, L¿ααα? is an organic complex and n is the combined valence state of M1 and M2.

Description

Mixed Metal Organic Complexes

The present invention relates to mixed metal complexes of transition metals and other metals which are electroluminescent and photoluminescent.

Materials which emit light when an electric current is passed through them are well known and used in a wide range of display applications. Liquid ciystal devices and devices which are based on inorganic semiconductor systems are widely used, however these suffer from the disadvantages of high energy consumption, high cost of manufacture, low quantum efficiency and the inability to make flat panel displays.

Organic polymers have been proposed as useful in electroluminescent devices, but it is not possible to obtain pure colours, they are expensive to make and have a relatively low efficiency.

Another compound which has been proposed is aluminium quinolate, but this requires dopants to be used to obtain a range of colours and has a relatively low efficiency.

Patent application WO98/58037 describes a range of lanthanide complexes which can be used in electroluminescent devices which have improved properties and give better results. Patent Applications PCT/GB98/01773, PCT/GB99/03619, PCT/GB99/04030, PCT/GB99/04024, PCT/GB99/04028, PCT/GBOO/00268 describe electroluminescent complexes, structures and devices using rare earth chelates.

Hitherto electroluminescent metal complexes have been based on a rare earth, transition metal, lanthanide or an actinide or have been quinolates such as aluminium quinolate. We have now invented new metal complexes which include a rare earth, transition metal, lanthanide or an actinide and a non rare earth, transition metal, lanthanide or an actinide.

According to the invention there is provided complexes of general formula (L_α)_nMιM₂ where M_\ is a rare earth, transition metal, lanthanide or an actinide, M₂ is a non rare earth metal, L_α is an organic complex and n is the combined valence state of Mi and M₂.

Preferably the complex can also comprise one or more neutral ligands L_p so the complex has the general formula (L_α)_n M_\ M (L_p), where L_p is a neutral ligand.

There can be more than one group L_α and more than one group L_p and each of which group may be the same or different.

Mi can be any metal ion having an unfilled inner shell which can be used as the metal and the preferred metals are selected from Sm(III), Eu(II), Eu(III), Tb(III), Dy(III), Yb(III), Lu(III), Gd (III), U(III), U(VI)O₂, Tm(III), Th(IV), Ce (III), Ce(IV), Pr(IiI), Nd(III), Pm(III), Dy(III), Ho(III), Er(III).

The metal M can be any metal which is not a rare earth, lanthanide or an actinide examples of metals which can be used include lithium, sodium, potassium, rubidium, caesium, beryllium, magnesium, calcium, strontium, barium, copper, silver, gold, zinc, cadmium, boron, aluminium, gallium, indium, germanium, tin, antimony, lead, and metals of the first, second and third groups of transition metals e.g. manganese, iron, ruthenium, osmium, cobalt, nickel, palladium, platinum, cadmium, chromium, titanium, vanadium, zirconium, tantulum, molybdenum, rhodium, iridium, niobium, scandium, yttrium etc. The different groups (L_α) may be the same or different and can be selected from β diketones such as those of formulae

(I) or

(II) where R^ R and R₃ can be the same or different and are selected from hydrogen, hydrocarbyl groups, substituted and unsubstituted aliphatic groups substituted and unsubstituted aromatic, heterocychc and polycyclic ring structures, fluorocarbons such as trifluoryl methyl groups, halogens such as fluorine or thiophenyl groups; R_1; R₂ and R₃ can also be copolymerisable with a monomer e.g. styrene and where X is Se, S or O and Y is hydrogen, hydrocarbyl groups, substituted and unsubstituted aromatic, heterocychc and polycyclic ring structures, fluorine, fluorocarbons such as trifluoryl methyl groups, halogens such as fluorine or thiophenyl groups or nitrile. Examples of R₁ and/or R₂ and/or R include aliphatic, aromatic and heterocychc alkoxy, aryloxy and carboxy groups, substituted and substituted phenyl, fluorophenyl, biphenyl, phenanthrene, anthracene, naphthyl and fluorene groups alkyl groups such as t-butyl, heterocychc groups such as carbazole

Ri_, R₂ and R₃ can also be

where X is O, S, Se orNH.

A preferred moiety Ri is trifluoromethyl CF₃ and examples of such diketones are, banzoyltrifluoroacetone, p-chlorobenzoyltrifluoroacetone, p-bromotrifluoroacetone, p-phenyltrifluoroacetone, 1 -naphthoyltrifluoroacetone, 2-naphthoyltrifluoroacetone, 2-phenathoyltrifluoroacetone, 3-phenanthoyltrifluoroacetone, 9- anthroyltrifluoroacetonetrifluoroacetone, cinnamoyltrifluoroacetone, and 2- thenoyltrifluoroacetone.

The different groups (L_α) may be the same or different ligands of formulae

(III) where X is O, S, or Se and R_\ R₂ and R₃ are as above The different groups (L_α) may be the same or different quinolate derivatives such as

(IV) (V) where R is hydrocarbyl, aliphatic, aromatic or heterocychc carboxy, aryloxy, hydroxy or alkoxy e.g. the 8 hydroxy quinolate derivatives or

(VII) where R is as above or H or F or

or

(VIII)

(XIX) The different groups (L_α) may also be the same or different carboxylate groups

O

R₅— C

O

(X)

where R₅ is a substituted or unsubstituted aromatic, polycyclic or heterocychc ring a polypyridyl group, R₅ can also be a 2-ethyl hexyl group so L_α is 2-ethylhexanoate or R₅ can be a chair structure so that L_α is 2-acetyl cyclohexanoate or L can be

R

(XI)

where R and R are as above e.g. alkyl, allenyl, amino or a fused ring such as a cyclic or polycyclic ring. The different groups (L_α) may also be

(XII) (XIII)

(XIV) (XV)

(XVI) (XVII) Where Ri and R₂ are as above. The groups Lp can be selected from

Ph Ph

O N Ph

Ph Ph

(XVIII)

where each Ph which can be the same or different and can be a phenyl (OPNP) or a substituted phenyl group, other substituted or unsubstituted aromatic group, a substituted or unsubstituted heterocyclic or polycyclic group, a substituted or unsubstituted fused aromatic group such as a naphthyl, anthracene, phenanthrene, perylene or pyrene group. The substituents can be for example an alkyl, aralkyl, alkoxy, aromatic, heterocyclic, polycyclic group, halogen such as fluorine, cyano, amino and substituted amino groups etc. Examples are given in figs. 1 to 3 of the drawings where R, R_1; R_2; R and R can be the same or different and are selected from hydrogen, hydrocarbyl groups, substituted and unsubstituted aromatic, heterocyclic and polycyclic ring structures, fluorocarbons such as trifluoryl methyl groups, halogens such as fluorine or thiophenyl groups; R, R_1; R₂, R₃ and R₄ can also form substituted and unsubstituted fused aromatic, heterocyclic and polycyclic ring structures and can be copolymerisable with a monomer e.g. styrene. R, Ri_, R_2; R₃ and R can also be unsaturated alkylene groups such as vinyl groups or groups

-CH ^■2, ^:CH^> '2, R where R is as above.

L_p can also be compounds of formulae

(XIX) (XX)

(XXI) (XXII) where R_1? R₂ and R₃ are as referred to above, for example bathophen shown in fig. 3 of the drawings in which R is as above.

L_p can also be

Ph

Ph Ph or Ph Ph

(XXIII) (XXIV) where Ph is as above.

Other examples of L_p are as shown in figs. 4 to 8 Specific examples of L_α and L_p are tripyridyl and TMHD, and TMHD complexes, α, α', α" tripyridyl, crown ethers, cyclans, cryptans phthalocyanans, porphoryins ethylene diamine tetramine (EDTA), DCTA, DTPA and TTHA. Where TMHD is 2,2,6,6- tetramethyl-3,5-heptanedionato and OPNP is diphenylphosphonimide triphenyl phosphorane. The formulae of the polyamines are shown in fig. 9.

The mixed complexes can be made by reacting a mixture of salts of the metals with the organic complexes as in conventional methods of making the transition metal complexes.

Examples of complexes of the present invention include Eu(DBM)₃OPNP, Tb(tmhd)₃OPNP, Eu(Zn(DBM)₅OPNP etc.

The mixed complexes are photoluminescent and electroluminescent and their use in electroluminescent devices is described in our co-pending application GB

The preparation of complexes according to the invention are illustrated in the following examples.

EXAMPLE 1 - Preparation of EuZn(DBM)₅(OPNP)

A mixture of dibenzoylmethane (DBM) (4.1 g; 0.0 18 mole) and OPNP (3.5 g; 0.007 mole) was dissolved in ethanol (40 ml) by warming the magnetically stirred solution. A solution containing ZnCl (0.5 g; 0.0037 mole) and EuCl₃ (1.34 g; 0.0037 mole) in water (10 ml) was added to the reaction mixture, followed by 2N NaOH solution until the pH was 6-7. The precipitate was filtered off, washed with water and ethanol and dried under vacuum at 80 °C for 16 hours. The product had a M.P. of 182 °C. Films of the product were obtained by dissolving the product in a solvent and evaporating from the solution.

Elemental analysis: Found C 69.59, H 4.56, N 0.79. C₁₀₅H₈₀OπNP₂EuZn requires C 69.63, H 4.45 and N 0.77. The elemental analysis indicates there was only one OPNP.

The ultraviolet spectrum was

UV (λmax) nm (thick evaporated film): 356, 196

UV (λmax) nm (thin evaporated film): 362

UV (λmax) nm (thin film made from CH₂C1₂ solution): 360, 195

TGA: °C (% weight loss): 350(11), 444 (39) and 555 (80)

The photoluminescent colour had co-ordinates: x 0.66, y 0.33

EXAMPLE 2 - EuAl(DBM)₆OPNP

A warm ethanolic solution (50 ml) of dibenzoylmethane (DBM) (3.67g. 0.016 mole) was mixed with an ethanolic solution (30 ml) of OPNP (2.60g. 0.005 mole). NaOH (0.65g, 0.0 16 mole) in water (30 ml) was added to the ligand (DBM) solution while stirring. The solution became dark yellow. The solution was stirred for 10 minutes. After 10 minutes, a mixture of EuCl₃.6H₂0 (lg 0.0027 mole) in ethanol: water (1:1) (20 ml) and A1C1₃.6H₂0 ( 0.658g. 0.0027 mole) in water (20 ml) was slowly added while stirring. The reaction mixture was stirred for 5 hours at 60°C. The yellow colour product was suction filtered and thoroughly washed with water followed by ethanol. Product was vacuum dried at 80°C. Analysis showed it to be EuAL(DBM)₆OPNP.

Claims

1. A complex of general formula (L_α)_nMιM where Mi is a rare earth, transition metal, lanthanide or an actinide, M₂ is a non rare earth metal, L_α is an organic complex and n is the combined valence state of Mi and M₂.

2. A complex of general foraiula (L_α)_n Mi M₂ (L_p), where L_p is a neutral ligand and where Mi is a rare earth, transition metal, lanthanide or an actinide, M₂ is a non rare earth metal, L_α is an organic complex and n is the combined valence state of Mi and M₂.

3. A complex as claimed in claim 1 or 2 in which Mi is Sm(III), Eu(II), Eu(III), Tb(III), Dy(III), Yb(III), Lu(III), Gd (III), U(III), U(VI)O₂, Tm(III), Th(IV), Ce (III), Ce(IV), Pr(III), Nd(III), Pm(III), Dy(III), Ho(III) or Er(III).

4. A complex as claimed in claim 1, 2 or 3 in which M₂ is lithium, sodium, potassium, rubidium, caesium, beryllium, magnesium, calcium, strontium, barium, copper, silver, gold, zinc, cadmium, boron, aluminium, gallium, indium, germanium, tin, antimony, lead, and metals of the first, second and third groups of transition metals selected from manganese, iron, ruthenium, osmium, cobalt, nickel, palladium, platinum, cadmium, chromium, titanium, vanadium, zirconium, tantulum, molybdenum, rhodium, iridium, niobium, scandium, yttrium.

5. A complex as claimed in any one of claims 1 to 4 in which (L_α) has the formula (I) to (XVII) herein.

6. A complex as claimed in any one of claims 1 to 5 in which L_p has the formula herein (XVIII) to (XXIV) or of figures 1 to 9 of the drawings.

7. A complex as claimed in claim 2 of formula EuZn(DBM)₅OPNP, EuAl(DBM)₆OPNP or EuSc(DBM)₅OPNP, where OPNP has the formula (I) herein.