N-heteroaromatic ion and iminium ion substituted cyanine dyes for use as fluorescence labels

A cyanine dye having the formula ##STR28## wherein r is 1, 2 or 3;

• R.sub.1 and R.sub.2 are taken together to form an aromatic ring or a fused polycyclic aromatic ring;
• R.sub.3 and R.sub.4 are taken together to form an aromatic ring or a fused polycyclic aromatic ring;
• R.sub.5 and R.sub.6 are independently selected from the group consisting of (CH.sub.2).sub.p X where p is 1-18 and X is a functional group that reacts with amino, hydroxy or sulfhydryl nucleophiles;
• R.sub.7 and R.sub.8 are independently selected from the group consisting of hydrogen, C1-C10 alkyl and where R.sub.7 and R.sub.8 are taken together to form a five- or six- membered heterocyclic ring;
• Y is selected from the group consisting of C(CH.sub.3).sub.2 and S;
• and
• Z is selected from the group consisting of C(CH.sub.3).sub.2 and S.

Method for fluorescent labeling a molecule comprising:

• labeling a molecule having an amino, hydroxy or sulfhydryl functional group with a cyanine dye having the formula ##STR30## wherein n and m are each independently either 0, 1, 2 or 3;
• R.sub.1 and R.sub.2 are taken together to form an aromatic ring or a fused polycyclic aromatic ring;
• R.sub.3 and R.sub.4 are taken together to form an aromatic ring or a fused polycyclic aromatic ring;
• R.sub.5 and R.sub.6 are independently selected from the group consisting of (CH.sub.2).sub.p X where p is 1-18 and X is a functional group that reacts with amino, hydroxy or sulfhydryl nucleophiles;
• R.sub.7 and R.sub.8 are independently selected from the group consisting of hydrogen, C1-C10 alkyl and where R.sub.7 and R.sub.8 are taken together to form a five- or six- membered heterocyclic ring;
• R.sub.9 are each independently selected from the group consisting of hydrogen, alkyl and where more than one R.sub.9 are taken together to form a five- or six- membered ring;
• Y is selected from the group consisting of C(CH.sub.3).sub.2 and S;
• and
• Z is selected from the group consisting of C(CH.sub.3).sub.2 and S.

Method for fluorescent labeling a molecule comprising:

• labeling a molecule having an amino, hydroxy or sulfhydryl functional group with a cyanine dye having the formula ##STR31## wherein r is 1, 2 or 3;
• R.sub.1 and R.sub.2 are taken together to form an aromatic ring or a fused polycyclic aromatic ring;
• R.sub.3 and R.sub.4 are taken together to form an aromatic ring or a fused polycyclic aromatic ring;
• R.sub.5 and R.sub.6 are independently selected from the group consisting of (CH.sub.2).sub.p X where p is 1-18 and X is a functional group that reacts with amino, hydroxy or sulfhydryl nucleophiles;
• R.sub.7 and R.sub.8 are independently selected from the group consisting of hydrogen, C1-C10 alkyl and where R.sub.7 and R.sub.8 are taken together to form a five- or six- membered heterocyclic ring;
• Y is selected from the group consisting of C(CH.sub.3).sub.2 and S;
• and
• Z is selected from the group consisting of C(CH.sub.3).sub.2 and S.