A compound of Formula I wherein L is a phosphine (PR 1 R 2), a sulfide (SR 1), or a carbene group (CR 1); each Y is independently a C, N or S atom, wherein at least two Y's are C; the dotted lines simultaneously or independently represent single or double bonds; R 1 and R 2 are each independently, a C 5 -C 20 aryl, each of which may be optionally substituted, or OR or NR 2; or when taken together, R 1 and R 2 can together with L to which they are bound form a saturated or partially saturated ring; R 3 is H, or a C 3 -C 8 linear alkyl, a C 3 -C 8 branched alkyl, a C 3 -C 8 cyclic alkyl, a C 3 -C 8 alkenyl, or a C 5 -C 8 aryl, each of which may be optionally substituted; R 4 is H; or R 3 and R 4 can join together to form a saturated heterocycle; R 5 is H, a linear C 3 -C 8 alkyl, a branched C 3 -C 8 alkyl, a cyclic C 3 -C 8 alkyl, a C 3 -C 8 alkenyl, or a C 5 -C 8 aryl, each of which can be optionally substituted; or R 5 and R 4 can join together to form a saturated heterocycle; each X is independently H, a linear C 3 -C 8 alkyl, a branched C 3 -C 8 alkyl, a cyclic C 3 -C 8 alkyl, a C 3 -C 8 alkenyl, or a C 5 -C 8 aryl, or OR, F, Cl, Br, I or NR 2; or when taken together, two of the X groups can together form an optionally substituted, saturated, partially saturated, aromatic or heteroaromatic ring; R is H, a C 1 -C 20 linear alkyl, a C 3 -C 20 branched alkyl, a C 3 -C 8 cycloalkyl, a C 2 -C 8 alkenyl, or a C 5 -C 8 aryl, each of which may be optionally substituted; each n and m is independently 1 or 2; k is 1 or 2; and z is 0 or 1; alkenyl means a hydrocarbon moiety that is linear, branched or cyclic and comprises at least one carbon to carbon double bond and, wherein the optional substituents are selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, aryl-halide, heteroaryl, cycloalkyl (non-aromatic ring), Si(alkyl)3, Si(alkoxy)3, halo, alkoxyl, amino, alkylamino, alkenylamino, amide, amidine, hydroxyl, thioether, alkylcarbonyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carbonate, alkoxycarbonyl, aminocarbonyl, alkylthiocarbonyl, phosphate, phosphate ester, phosphonato, phosphinato, cyano, acylamino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, dithiocarboxylate, sulfate, sulfato, sulfonate, sulfamoyl, sulfonamide, nitro, nitrile, azido, heterocyclyl, ether, ester, silicon-containing moieties, thioester, or a combination thereof. L is a phosphine (PR 1 R 2), a sulfide (SR 1), or a carbene group (CR 1); each Y is independently a C, N or S atom, wherein at least two Y's are C; the dotted lines simultaneously or independently represent single or double bonds; R 1 and R 2 are each independently, a C 5 -C 20 aryl, each of which may be optionally substituted, or OR or NR 2; or when taken together, R 1 and R 2 can together with L to which they are bound form a saturated or partially saturated ring; R 3 is H, or a C 3 -C 8 linear alkyl, a C 3 -C 8 branched alkyl, a C 3 -C 8 cyclic alkyl, a C 3 -C 8 alkenyl, or a C 5 -C 8 aryl, each of which may be optionally substituted; R 4 is H; or R 3 and R 4 can join together to form a saturated heterocycle; R 5 is H, a linear C 3 -C 8 alkyl, a branched C 3 -C 8 alkyl, a cyclic C 3 -C 8 alkyl, a C 3 -C 8 alkenyl, or a C 5 -C 8 aryl, each of which can be optionally substituted; or R 5 and R 4 can join together to form a saturated heterocycle; each X is independently H, a linear C 3 -C 8 alkyl, a branched C 3 -C 8 alkyl, a cyclic C 3 -C 8 alkyl, a C 3 -C 8 alkenyl, or a C 5 -C 8 aryl, or OR, F, Cl, Br, I or NR 2; or when taken together, two of the X groups can together form an optionally substituted, saturated, partially saturated, aromatic or heteroaromatic ring; R is H, a C 1 -C 20 linear alkyl, a C 3 -C 20 branched alkyl, a C 3 -C 8 cycloalkyl, a C 2 -C 8 alkenyl, or a C 5 -C 8 aryl, each of which may be optionally substituted; each n and m is independently 1 or 2; k is 1 or 2; and z is 0 or 1; alkenyl means a hydrocarbon moiety that is linear, branched or cyclic and comprises at least one carbon to carbon double bond and, wherein the optional substituents are selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, aryl-halide, heteroaryl, cycloalkyl (non-aromatic ring), Si(alkyl)3, Si(alkoxy)3, halo, alkoxyl, amino, alkylamino, alkenylamino, amide, amidine, hydroxyl, thioether, alkylcarbonyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carbonate, alkoxycarbonyl, aminocarbonyl, alkylthiocarbonyl, phosphate, phosphate ester, phosphonato, phosphinato, cyano, acylamino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, dithiocarboxylate, sulfate, sulfato, sulfonate, sulfamoyl, sulfonamide, nitro, nitrile, azido, heterocyclyl, ether, ester, silicon-containing moieties, thioester, or a combination thereof.