Material selecting method upon purifying iridium complex by sublimation

1. A method for selecting an iridium complex represented by the following formula (1) comprising:

selecting the iridium complex represented by the following formula (1) and having a rate of weight loss of 45% or greater when the iridium complex is heated to 500° C. at 2° C./min under a degree of vacuum of from 1×10 −3 Pa to 1×10 −1 Pa; and

carrying out a sublimation purification of the iridium complex:

wherein

each of R 3 , R 4 , R 5 , R 6 , and R 3 ′ independently represents a hydrogen atom an alkyl group, an alkenyl group, an alkynyl group, —CN, —CF 3 , —C n F. 2n+1 , a trifluorovinyl group, —CO 2 R, —C(O)R, —NR 2 , —NO 2 , —OR, a halogen atom, an aryl group, or a heteroaryl group and may further have a substituent Z, wherein each of Rs independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group and may further have a substituent; each of Zs independently represents a halogen atom —R′, —OR′, —N(R′) 2 , —SR′, —C(O)R′, —C(O)OR′, —C(O)N(R′) 2 —, —CN, —NO 2 , —SO 2 , —SOR′, —SO 2 R′, or —SO 3 R′, each of R′s independently represents a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group;

R 3 ′ and R 6 may be linked to form a ring via a linking group selected from —CR 2 —CR 2 —, —CR═CR—, —CR 2 —, O—, —NR—, —O—CR 2 —, —NR—CR 2 —, and —N═CR—, wherein each of Rs independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group or a heteroaryl group and may further have a substituent;

R 3 and R 4 may be coupled to each other to form a condensed four- to seven-membered ring and the condensed four- to seven-membered ring is a cycloalkane ring, cycloheteroalkane ring, aromatic hydrocarbon ring, or heteroaromatic ring and may further have a substituent, wherein cycloheteroalkane ring has 1-30 carbon atom and a nitrogen atom, an oxygen atom, or sulfur atom as a heteroatom, and wherein heteroaromatic ring is selected from the group consisting of imidazolyl, pyrazolyl, pyridyl, pyrazyl, pyrimidyl, triazinyl, quinolyl, isoquinolinyl, pyrrolyl, indolyl, furyl, thienyl, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl, and azepinyl;

R 4 and R 5 may be coupled to each other to form a five- or six-membered ring, wherein the ring may further have a substituent;

the ring Q represents 6-membered heteroaryl ring having one nitrogen atom as heteroatom which is fused to a 6-membered aryl ring coordinated to iridium;

(X-Y) represents acetylacetonate or picolinate, or derivatives thereof; and

n stands for an integer from 1 to 3.

2. The method according to claim 1 , wherein when the iridium complex is heated at 10° C./min under ordinary pressure, the iridium complex shows an endothermic change as a thermal change in a range of a rate of weight loss of from 1 to 5 mass %.

3. The method according to claim 1 , wherein the ring Q is condensed and at least one of R 3 , R 4 , R 5 , and R 6 represents a methyl group or a phenyl group, with the proviso that when at least one of R 3 , R 4 , R 5 , and R 6 represents a phenyl group, the phenyl group may further have a substituent or the phenyl group may be coupled to the ring Q via a single bond.

4. The method according to claim 1 , wherein the iridium complex is represented by the following formula (T-4):

wherein R 3 ′ represents a hydrogen atom, an alkyl group, a heteroalkyl group, an aryl group, or a heteroaryl group and may further have a substituent Z;

each of R 3 , R 4 , R 5 , and R 6 independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, —CN, —CF 3 , —C n F 2n+1 , a trifluorovinyl group, —CO 2 R, —C(O)R, —NR 2 , —NO 2 , —OR, a halogen atom, an aryl group, or a heteroaryl group and may further have a substituent Z, wherein each of Rs independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group and may further have a substituent;

each of Zs independently represents a halogen atom, —R′, —OR′, —N(R′) 2 , —SR′, —C(O)R′, —C(O)OR′, —C(O)N(R′) 2 —, —CN, —NO 2 , —SO 2 , —SOR′, —SO 2 R′, or —SO 3 R′, each of R′s independently represents a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group;

R 4 and R 5 may be coupled to each other to form a five- or six-membered ring, wherein the ring may further have a substituent;

(X-Y) represents acetylacetonate or picolinate, or derivatives thereof; and

n stands for an integer from 1 to 3.

5. The method according to claim 1 , wherein the iridium complex is purified by column chromatography.