Fluorescent metal sensors, and methods of making and using the same

A ligand for metal ions, comprising the following moiety:

• wherein:
• X is N;
• Q is O, S or Se;
• K is selected independently and optionally from the group consisting of halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamido, ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromatic moieties, —CF3, and —CN;
• V is independently each a Lewis base capable of forming one or more coordination bonds with a metal ion, and in the case when m is 2, both V do not contain —CO2H disposed in a manner to allow for coordination of both of said —CO2H to a single metal ion;
• R1 is independently hydrogen, alkyl, cycloalkyl, aryl, aryl, heterocycle or heterocycle;
• m is 1 or 2, and n is equal to (2−m);
• Y is O, S, Se, NR1, or C(CH3)3;
• and
• Z is N, HOOCCH2CH2C, HOOC—CH═CH—C, (2-carboxyphenyl)-C, (2-sulfophenyl)-C, (2-carboxy-3,4,5,6-tetrachlorophenyl)-C, (2-carboxy-4-nitrophenyl)-C, (2-carboxy-5-nitrophenyl)-C, (2-carboxy-4-aminophenyl)-C, (2-carboxy-5-aminoyphenyl)-C, (2,4-dicarboxyphenyl)-C, (2,5-dicarboxylphenyl)-C, (2,4,5-tricarboxyphenyl)C-, and other substituted (2-carboxyphenyl)-C moieties.