Aqueous electrolytes comprising fluorenone/fluorenol derivatives are disclosed. The electrolyte may be an anolyte for an aqueous redox flow battery. In some embodiments, the compound, or salt thereof, has a structure according to any one of formulas I-III ##STR00001##
where Q.sup.1-Q.sup.4 independently are CH, C(R.sup.1) or N, wherein 0, 1, or 2 of Q.sup.1-Q.sup.4 are N; Q.sup.5-Q.sup.8 independently are CH, C(R.sup.2), or N, wherein 0, 1, or 2 of Q.sup.5-Q.sup.8 are N; Y is C═O or C(H)OH; R.sup.1 and R.sup.2 independently are an electron withdrawing group; n is an integer >1; and x and y independently are 0, 1, 2, 3, or 4, where at least one of x and y is not 0.

Provided are compounds of Formula (I):

##STR00001##

or a pharmaceutically acceptable salt thereof, wherein R.sup.1, R.sup.2A, R.sup.2B, R.sup.3, R.sup.4, and R.sup.5 are as defined herein. Also provided is a pharmaceutically acceptable composition comprising a compound of Formula (I), or a pharmaceutically acceptable salt thereof. Also provided are methods of using a compound of Formula (I), or a pharmaceutically acceptable salt thereof.

Provided are compounds of Formula (I):

##STR00001##

or a pharmaceutically acceptable salt thereof, wherein R.sup.1, R.sup.2A, R.sup.2B, R.sup.3, R.sup.4, and R.sup.5 are as defined herein. Also provided is a pharmaceutically acceptable composition comprising a compound of Formula (I), or a pharmaceutically acceptable salt thereof. Also provided are methods of using a compound of Formula (I), or a pharmaceutically acceptable salt thereof.

An organic EL device includes a first emitting layer and a second emitting layer, in which the first emitting layer contains a first host material, the second emitting layer contains a second host material, the first and the second host material are mutually different, the first emitting layer and the second emitting layer at least contains a compound that emits fluorescence having a main peak wavelength of 500 nm or less, respectively, the compound contained in the first emitting layer and that emits fluorescence having a main peak wavelength of 500 nm or less is the same as or different from the compound contained in the second emitting layer, and a triplet energy T.sub.1(H1) of the first host material and a triplet energy T.sub.1(H2) of the second host material satisfy a numerical formula (Numerical Formula 1),

T.sub.1(H1)>T.sub.1(H2)  (Numerical Formula 1).

An organic EL device includes a first emitting layer and a second emitting layer, in which the first emitting layer contains a first host material, the second emitting layer contains a second host material, the first and the second host material are mutually different, the first emitting layer and the second emitting layer at least contains a compound that emits fluorescence having a main peak wavelength of 500 nm or less, respectively, the compound contained in the first emitting layer and that emits fluorescence having a main peak wavelength of 500 nm or less is the same as or different from the compound contained in the second emitting layer, and a triplet energy T.sub.1(H1) of the first host material and a triplet energy T.sub.1(H2) of the second host material satisfy a numerical formula (Numerical Formula 1),

T.sub.1(H1)>T.sub.1(H2)  (Numerical Formula 1).

The present disclosure relates to a plurality of host materials comprising a first host material having a compound represented by formula 1, and a second host material having a compound represented by formula 2, and an organic electroluminescent device comprising the same. By comprising a specific combination of compounds of the present disclosure as host materials, it is possible to provide an organic electroluminescent device having long lifetime properties while having an equivalent or improved level of power efficiency compared to conventional organic electroluminescent devices.

To improve the emission efficiency, the driving voltage and the lifetime of an organic light-emitting device using a delayed fluorescent material. A host material for a delayed fluorescent material, containing a compound represented by the following general formula: R.sup.1 to R.sup.5 each are a substituent not containing a cyano group. n1 to n5 each are 0 to 4, Ar is a monocyclic arylene group or a monocyclic heteroarylene group.

##STR00001##

Provided are compounds of Formula (II) or a pharmaceutically acceptable salt thereof, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and p are as defined herein. Also provided is a pharmaceutically acceptable composition comprising a compound of Formula (II), or a pharmaceutically acceptable salt thereof. Also provided are methods of using a compound of Formula (II), or a pharmaceutically acceptable salt thereof.

##STR00001##

Provided are compounds of Formula (II) or a pharmaceutically acceptable salt thereof, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and p are as defined herein. Also provided is a pharmaceutically acceptable composition comprising a compound of Formula (II), or a pharmaceutically acceptable salt thereof. Also provided are methods of using a compound of Formula (II), or a pharmaceutically acceptable salt thereof.

##STR00001##

The present disclosure relates to prodrugs, double prodrugs, derivatives and analogues of 3-(methylamino)-2-((methylamino)methyl)propane-1-thiol. The compounds of this disclosure also relate to formula I:

##STR00001##

The use of these compounds as radio- and chemo-protectors is also described.