On the basis of preparation and characterization of [Fe]-H(2)ase models (2-COCH2-6-HOCH2C5H3N)Fe(CO)(2)L (A, L = eta(1)-SCOMe; B, L = eta(1)-2-SC(5)H4N), the chemical reactivities of A and B with various electrophilic and nucleophilic reagents have been investigated, systematically. Thus, when A reacted with 1 equiv of MeCOCl in the presence of Et3N in MeCN to give the eta(2)-SCOMe-coordinated acylation product (2-COCH2-6-MeCO2CH2C5H3N)Fe(CO)2(eta(2)-SCOMe) (1), treatment of A with excess HBF4Et2O in MeCN gave the cationic MeCN-coordinated complex [(2-COCH2-6-HOCH2C5H3N)Fe(CO)(2)(MeCN)](BF4) (2). In addition, when 2 was treated with 1 equiv of 2,6-(p-4-MeC6H4)2C(6)H(3)SK or PPh3 in CH2Cl2 to give the thiophenolato- and PPh3-substituted derivatives (2-COCH2-6-HOCH2C5H3N)Fe(CO)2[2,6-(p-MeC6H4)2C(6)H(3)S] (3) and [(2-COCH2-6-HOCH2C5H3N)Fe(CO)(2)(PPh3)](BF4) (4), treatment of B with 1 equiv of PMe3 or P(OMe)3 in THF afforded the phosphine- and phosphite-substituted complexes (2-COCH2-6-HOCH2C5H3N)(eta(1)-2-SC(5)H4N)Fe(CO)2L (5, L = PMe3; 6, L = P(OMe)3). Interestingly, in contrast to A, when B reacted with excess HBF4Et(2)O in MeCN to afford the BF3 adduct [2-COCH2-6-HO(BF3)CH2C5H3N]Fe(CO)2(eta(1)-2-SC5H4N) (7), reaction of B with 1 equiv of p-MeC6H4COCl in the presence of Et3N in MeCN gave not only the expected 2-acylmethyl-6-p-toluoyloxomethylpyridine-containing complex (2-COCH2-6-p-MeC6H4CO2CH2C5H3N)Fe(CO)2(eta(2)-2-SC5H4N) (8), but also gave the unexpected 2-toluoyloxovinyl-6-toluoyloxomethylpyridine-containing complex (2-p-MeC6H4CO2C2H-6-p-MeC6H4CO2CH2C5H3N)Fe(CO)2(eta(2)-2-SC5H4N) (9). While the possible pathways for the novel reactions leading to complexes 1, 2, and 79 are suggested, the structures of complexes B, 14, and 69 were unambiguously confirmed by X-ray crystallography. In addition, model complexes A and B have been found to be catalysts for proton reduction to H-2 from TFA under CV conditions.