Ruthenium(II) hydrotris(pyrazolyl)borate chloro complexes bearing picolyl-functionalized N-heterocyclic carbenes [TpRu-(kappa(2)-C,N-picolyl-R-I)Cl] (picolyl-I-Me = 3-methyl-1-(2-picolyl)imidazol-2-ylidene) = 3-isopropyl-1-(2-picolypimidazol-2-ylidene (1b), picolyl-(Me)45DCI1 = 3-methyl-1-(2-picolyl)-4,5-dichloroimidazol-2-ylidene (1c), picolyl-(Ph)l = 3-phenyl-1-(2-picolyl)imidazol-2-ylidene (1d), picolyl-(BI)-B-Me = 3-methyl-1-(2-picolypbenzoimidazol-2-ylidene (1e)) have been synthesized and characterized. Furthermore, cationic carbonyl derivatives 2a-e have been prepared, characterized, and used to study the donor properties of the picolylcarbene ligands (picolyl-I-R) via infrared spectroscopy. Also, the reactivity of the 16-electron species [TpRu(kappa(2)-C,N-picolyl-I-R)](+), in situ generated using NaBAr4F (Ar-F = 3,5-bis(trifluoromethyl)phenyl) as a halide scavenger, toward N-2, CH3CN, H-2, CH2CH2, S-8, and O-2 was studied indicating a strong influence of the NHC wingtip and backbone substituents in the product distribution. The crystal structures of [TpRu(kappa(2)-C,N-picolyl-I-iPr)Cl] (1b), [TpRu(kappa(2)-C,N-picolyl-I-Me)CO] [BAr4F] (2a), [TpRu(kappa(2)-C,N-picolyl-I-Ph)CO][BAr4F] (2d), [{TpRu(kappa(2)-C,N-picolyl-I-Me}(2)(mu-N-2)][BAr4F](2) (3'a), [{TpRu(kappa(2)-C,N-picolyl-I-Ph))(2)(mu-S-2)] [BAr4F](2) (3'd), [TpRu(kappa(2)-C,N-picolyl-I-iPr)(eta(2)-CH2CH2)][BAr4F] (5b), and [{TpRu(kappa(2)-C,N-picolyl-I-Me)}(2)(mu-S-2)][BAr4F](2) (6) are reported.