Phosphorescent organic compounds

1. A crystalline composition exhibiting metal-independent phosphorescence comprising:

a first portion comprising a carbonyl group bonded to an aromatic group or an aromatic group having extended π-conjugation;

a second portion comprising a halogen atom bonded to an aromatic group or an aromatic group having extended π-conjugation; and

a non-covalent interaction between the oxygen of the carbonyl group and the halogen atom, wherein the distance between the oxygen of the carbonyl group and the halogen atom is less than the van der Waals radii of the oxygen of the carbonyl group and the halogen atom.

2. The composition of claim 1 , wherein the composition exhibits a quantum yield from about 1% to about 68%.

3. The composition of claim 1 , wherein the distance between the oxygen and the halogen is less than 3.37 A.

4. The composition of claim 1 , wherein the carbonyl group is —CHO.

5. The composition of claim 1 , further comprising a polymer.

6. The composition of claim 5 , wherein the polymer comprises poly(methylacrylate), poly(methylmethacrylate), poly(styrene), or poly(α-methyl styrene).

7. The composition of claim 1 , wherein the non-covalent interaction is intermolecular.

8. The composition of claim 1 , wherein the composition comprises a compound of formula I:

wherein

R 1 is an aromatic group or an aromatic group having extended π-conjugation;

R 2 is a hydrogen or alkyl group;

R 3 and R 4 are independently hydrogen, alkyl, alkoxy, or alkylsulfane groups optionally substituted with one or more heteroatoms; and

X is a halogen atom.

9. The composition of claim 8 , wherein

R 1 is a phenyl or napthyl group;

R 2 is hydrogen;

R 3 and R 4 are independently hexyl, heptyl, 2-ethylhexyl, methoxy, butyloxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, or hexylsulfane; and

X is a bromine, chlorine, or iodine atom.

10. The composition of claim 9 , wherein the compound of formula I comprises 4-bromo-2,5-diheptylbenzaldehyde; 2,5-dihexyloxy-4-bromobenzaldehyde; 4-bromo-2,5-bis(hexylthio)benzaldehyde; 5-bromo-2,6-bis(hexyloxy)-1-naphthaldehyde, or 4-bromo-2,5-di((2-ethylhexyl)oxy)benzaldehyde; 2,5-dimethoxy-4-bromobenzaldehyde; 4-bromo-2,5-dihexylbenzaldehyde; 2,5-dibutyloxy-4-bromobenzaldehyde; 2,5-dipentyloxy-4-bromobenzaldehyde; 2,5-diheptyloxy-4-bromobenzaldehyde; or 2,5-dioctyloxy-4-bromobenzaldehyde.

11. The composition of claim 8 , further comprising a compound of formula II:

wherein

R 5 is an aromatic group or an aromatic group having extended π-conjugation;

R 6 and R 7 are independently hydrogen, alkyl, alkoxy, or alkylsulfane groups optionally substituted with one or more heteroatoms; and

X is a halogen atom.

12. The composition of claim 11 , wherein

R 5 is a phenyl or napthyl group;

R 6 and R 7 are independently hexyl, heptyl, 2-ethylhexyl, methoxy, butyloxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, or hexylsulfane; and

X is a bromine, chlorine, or iodine atom.

13. The composition of claim 12 , wherein

the compound of formula I comprises 4-bromo-2,5-diheptylbenzaldehyde; 2,5-dihexyloxy-4-bromobenzaldehyde; 4-bromo-2,5-bis(hexylthio)benzaldehyde; 5-bromo-2,6-bis(hexyloxy)-1-naphthaldehyde, or 4-bromo-2,5-di((2-ethylhexyl)oxy)benzaldehyde; 2,5-dimethoxy-4-bromobenzaldehyde; 4-bromo-2,5-dihexylbenzaldehyde; 2,5-dibutyloxy-4-bromobenzaldehyde; 2,5-dipentyloxy-4-bromobenzaldehyde; 2,5-diheptyloxy-4-bromobenzaldehyde; or 2,5-dioctyloxy-4-bromobenzaldehyde; and

the compound of formula II comprises 1,4-dibromo-2,5-diheptylbenzene; 2,5-dihexyloxy-1,4-dibromobenzene; (2,5-dibromo-1,4-phenylene)bis(hexylsulfane); 1,5-dibromo-2,6-bis(hexyloxy)naphthalene; 1,4-dibromo-2,5-dimethoxybenzene; 1,4-dibromo-2,5-dihexylbenzene; 2,5-dibutyloxy-1,4-dibromobenzene; 2,5-dipentyloxy-1,4-dibromobenzene; 2,5-diheptyloxy-1,4-dibromobenzene; or 2,5-dioctyloxy-1,4-dibromobenzene.

14. The composition of claim 1 , wherein the non-covalent interaction is intramolecular.

15. The composition of claim 14 , comprising a compound of formula III:

wherein

R 2 is a hydrogen or alkyl group;

R 8 is an aromatic group or an aromatic group having extended π-conjugation;

R 9 and R 10 are independently hydrogen, alkyl, alkoxy, or alkylsulfane groups optionally substituted with one or more heteroatoms; and

X is a halogen atom.

16. The composition of claim 15 , wherein

R 2 is hydrogen;

R 8 is a biphenylene, fluorene, 1,2-diphenylethene, or 1,2-distyrylbenzene group;

R 9 and R 10 are ethyloxy groups; and

X is a bromine, chlorine, or iodine atom.

17. The composition of claim 16 , wherein the compound of formula III comprises 8-bromo-3,6-diethoxybiphenylene-1-carbaldehyde; 4,5,8-tribromo-3,6-diethoxybiphenylene-1-carbaldehyde; 5-bromo-2,7-diethoxy-9H-fluorene-4-carbaldehyde; 2-(2-bromo-5-ethoxystyryl)-4-ethoxybenzaldehyde; 2-(2-bromo-4-ethoxystyryl)-5-ethoxybenzaldehyde; or 2-(2-(2-bromostyryl)-4,5-diethoxystyryl)benzaldehyde.

18. An article of manufacture comprising the composition of claim 1 , wherein the article of manufacture is a light emitting diode, organic photovoltaic material, flexible lighting display, solid-state lighting, polarized light emitting device, quantum dot, thin-film transistor, or phosphorescent nanowire.

19. A method of providing phosphorescence comprising:

providing a composition according to claim 1 ; and

exciting the composition with a first light while maintaining the distance between the oxygen of the carbonyl group and the halogen atom at less than the van der Waals radii of the oxygen of the carbonyl group and the halogen atom so that the composition absorbs at least a portion of the first light and emits a second light.

20. The method of claim 19 , wherein the distance between the oxygen of the carbonyl group and the halogen atom is maintained at less than the van der Waals radii of the oxygen of the carbonyl group and the halogen atom by crystallizing at least a portion of the composition, entangling the composition with a polymer, or providing the first portion and the second portion in a single compound so that the non-covalent interaction between the carbonyl oxygen and the halogen atom is via an intramolecular directed heavy atom effect.