A lipid having the structure XXXIII or a salt thereof, wherein: R 1 and R 2 are each independently for each occurrence optionally substituted C 10 -C 30 alkyl, optionally substituted C 10 -C 30 alkenyl, or optionally substituted C 10 -C 30 alkynyl, wherein in a substituted C 10 -C 30 alkyl, substituted C 10 -C 30 alkenyl, or substituted C 10 -C 30 alkynyl, one or more hydrogen radicals are replaced with halo, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, thiol, alkylthio, oxo, thioxy, arylthio, alkylthioalkyl, arylthioalkyl, alkylsulfonyl, alkylsulfonylalkyl, arylsulfonylalkyl, alkoxy, aryloxy, aralkoxy, aminocarbonyl, alkylaminocarbonyl, arylaminocarbonyl, alkoxycarbonyl, aryloxycarbonyl, haloalkyl, amino, trifluoromethyl, cyano, nitro, alkylamino, arylamino, alkylaminoalkyl, arylaminoalkyl, aminoalkylamino, hydroxy, alkoxyalkyl, carboxyalkyl, alkoxycarbonylalkyl, aminocarbonylalkyl, acyl, aralkoxycarbonyl, carboxylic acid, sulfonic acid, sulfonyl, phosphonic acid, aryl, heteroaryl, heterocyclic, or aliphatic, wherein said substituents may be further substituted with amino, alkylamino, dialkylamino, or cyclic amino compounds, and wherein at least one of R 1 or R 2 comprises at least one, at least two or at least three sites of unsaturation, or wherein R 1 and R 2 both comprise at least one, at least two or at least three sites of unsaturation; R 3 is ω-aminoalkyls, ω-(substituted)aminoalkyls, or heteroaryl, wherein in an ω-(substituted)aminoalkyl, at least one of the H on N has been replaced with alkyl; E is O, S, C(O), N(Q)C(O), C(O)N(Q), (Q)N(CO)O, O(CO)N(Q), S(O), NS(O) 2 N(Q), S(O) 2 , N(Q)S(O) 2 , SS, O=N; and, Q is H, or alkyl. R 1 and R 2 are each independently for each occurrence optionally substituted C 10 -C 30 alkyl, optionally substituted C 10 -C 30 alkenyl, or optionally substituted C 10 -C 30 alkynyl, wherein in a substituted C 10 -C 30 alkyl, substituted C 10 -C 30 alkenyl, or substituted C 10 -C 30 alkynyl, one or more hydrogen radicals are replaced with halo, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, thiol, alkylthio, oxo, thioxy, arylthio, alkylthioalkyl, arylthioalkyl, alkylsulfonyl, alkylsulfonylalkyl, arylsulfonylalkyl, alkoxy, aryloxy, aralkoxy, aminocarbonyl, alkylaminocarbonyl, arylaminocarbonyl, alkoxycarbonyl, aryloxycarbonyl, haloalkyl, amino, trifluoromethyl, cyano, nitro, alkylamino, arylamino, alkylaminoalkyl, arylaminoalkyl, aminoalkylamino, hydroxy, alkoxyalkyl, carboxyalkyl, alkoxycarbonylalkyl, aminocarbonylalkyl, acyl, aralkoxycarbonyl, carboxylic acid, sulfonic acid, sulfonyl, phosphonic acid, aryl, heteroaryl, heterocyclic, or aliphatic, wherein said substituents may be further substituted with amino, alkylamino, dialkylamino, or cyclic amino compounds, and wherein at least one of R 1 or R 2 comprises at least one, at least two or at least three sites of unsaturation, or wherein R 1 and R 2 both comprise at least one, at least two or at least three sites of unsaturation; R 3 is ω-aminoalkyls, ω-(substituted)aminoalkyls, or heteroaryl, wherein in an ω-(substituted)aminoalkyl, at least one of the H on N has been replaced with alkyl; E is O, S, C(O), N(Q)C(O), C(O)N(Q), (Q)N(CO)O, O(CO)N(Q), S(O), NS(O) 2 N(Q), S(O) 2 , N(Q)S(O) 2 , SS, O=N; and, Q is H, or alkyl. <EOS>