A method of inhibiting corrosion at a metal surface, the method comprising contacting the metal surface with a composition comprising a compound of formula, wherein either, R 1 and R 2 are selected from C 1 -C 10 -alkyl, each substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, and -CON(R 4) 2, R 1 and R 2 are selected from C 2 -C 10 -alkenyl, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, -NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2, wherein the C 2 -C 10 -alkenyl does not encompass diallyl disulfide, R 1 and R 2 are selected from C 2 -C 10 -alkynyl, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, -NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2, R 1 and R 2 are selected from C 6 -C 12 -aryl, each substituted with 1 to 3 substituents independently selected from the group consisting of -OH and -NH 2, R 1 and R 2 are selected from 5- to 10-membered heteroaryl, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, -NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2, wherein the 5- to 10- membered heteroaryl does not encompass dithienyl disulfide, R 1 and R 2 are selected from 5- to 10-membered heterocycle, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, -NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2, or R 1 and R 2 are selected from C 3 -C 8 -cycloalkyl, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH,-NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2; wherein R 3 and R 4, at each occurrence, are each independently selected from the group consisting of hydrogen and C 1 -C 6 alkyl; and wherein the composition provides 200 ppm or less of sulfur species in a headspace test, wherein the headspace test is characterized by: (a) placing 40 g of the composition into a 227 g(8 ounce) glass jar sealed with a cap containing a hole fitted with a rubber stopper which is used for sampling; (b) aging the composition of (a) in a 50 °C oven over a period of 10 days before sampling; and (c) sampling the headspace using sulfur detection tubes. R 1 and R 2 are selected from C 1 -C 10 -alkyl, each substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, and -CON(R 4) 2, R 1 and R 2 are selected from C 2 -C 10 -alkenyl, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, -NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2, wherein the C 2 -C 10 -alkenyl does not encompass diallyl disulfide, R 1 and R 2 are selected from C 2 -C 10 -alkynyl, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, -NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2, R 1 and R 2 are selected from C 6 -C 12 -aryl, each substituted with 1 to 3 substituents independently selected from the group consisting of -OH and -NH 2, R 1 and R 2 are selected from 5- to 10-membered heteroaryl, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, -NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2, wherein the 5- to 10- membered heteroaryl does not encompass dithienyl disulfide, R 1 and R 2 are selected from 5- to 10-membered heterocycle, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH, -NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2, or R 1 and R 2 are selected from C 3 -C 8 -cycloalkyl, each unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of -F, -Cl, -NO 2, -CN, -OH,-NH 2, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, -CO 2 R 3, and -CON(R 4) 2; wherein R 3 and R 4, at each occurrence, are each independently selected from the group consisting of hydrogen and C 1 -C 6 alkyl; and wherein the composition provides 200 ppm or less of sulfur species in a headspace test, wherein the headspace test is characterized by: (a) placing 40 g of the composition into a 227 g(8 ounce) glass jar sealed with a cap containing a hole fitted with a rubber stopper which is used for sampling; (b) aging the composition of (a) in a 50 °C oven over a period of 10 days before sampling; and (c) sampling the headspace using sulfur detection tubes. (a) placing 40 g of the composition into a 227 g(8 ounce) glass jar sealed with a cap containing a hole fitted with a rubber stopper which is used for sampling; (b) aging the composition of (a) in a 50 °C oven over a period of 10 days before sampling; and (c) sampling the headspace using sulfur detection tubes.