Lithium extraction with crown ethers

A compound of Formula (I):

• wherein
• R1, R2, R3, and R4 are each independently H, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, or heteroaryl, each of which are optionally substituted;
• or
• R1 and R2 and/or R3 and R4 taken together with the carbon atoms to which they are attached form a cycloalkyl or aryl ring, each of which is optionally substituted;
• R5 when present is H, alkyl, alkenyl, alkynyl, or cycloalkyl;
• R6 when present is —(CH2)rOH, -(CH2)rO-alkyl, —OH, -O-alkyl, -O-alkenyl, -O-alkynyl, -O-cycloalkyl;
• -O-aryl, —O—(CH2)tC(O)OR8, —O—(CH2)tS(O)2OR8, —O—(CH2)tS(O)2N(R8)2, —O—(CH2)tP(O)(OR8)2, —O—(CH2)tC(O)N(R9)2, each of which is optionally substituted;
• R7 is H, —OH, -O-alkyl, -O-alkenyl, -O-alkynyl, -O-cycloalkyl, —O—(CH2)tC(O)OR8, —O—(CH2)tS(O)2OR8, —O—(CH2)tS(O)2N(R8)2, —O—(CH2)tP(O)(OR8)2, or —O—(CH2)tC(O)N(R9)2;
• R8 is each independently H, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, aryl, alkylene-cycloalkyl, or alkylene-aryl;
• R9 is each independently H, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, alkylene-cycloalkyl, alkylene-aryl, or SO2R10;
• R10 is alkyl, cycloalkyl, or haloalkyl;
• m, n, p, and q are each independently 0 or 1;
• r is 1, 2, or 3;
• and
• t is independently 0, 1, or 2;
• with the proviso that when p is 0, at least two of R1, R2, R3, and R4 are not H.