•NHC+-CS2− (1) and (μ-κ2C:κ2S-NHC+-CS)[Fe2(CO)6]− (2) have been synthesized.•They have been fully characterized by EA, IR and NMR.•They have been structurally determined by X-ray crystallography.•Electrochemical study on 2 reveals that complex 2 can catalyze H2 production.Reaction of zwitterionic salt NHC+-CS2− (1), prepared from 1,3-diallylbenzimidazol-2-ylidene and CS2, with Fe3(CO)12 affords 2, (μ-κ2C:κ2S-NHC+-CS)[Fe2(CO)6]−. Two new compounds have been fully characterized by EA, IR, 1H NMR and 13C NMR spectroscopy and structurally determined by X-ray crystallography. Electrochemical study of 2 has demonstrated that using HOAc as a proton source complex 2 can efficiently catalyze H2 production.NHC+-CS2− (1) and (μ-κ2C:κ2S-NHC+-CS)[Fe2(CO)6]− (2) have been synthesized and fully characterized by EA, IR and NMR. They have been structurally determined by X-ray crystallography. Electrochemical study on 2 reveals that complex 2 can catalyze H2 production.

•Reaction of PhC(Se)NHCH2Ph, Et3N and Fe3(CO)12 affords the Se-centered salt.•Reaction of the Se-centered salt and Fe3(CO)12 forms the μ-CO-containing salt.•Reactions of the salts with electrophiles provide novel Fe/Se cluster complexes.The selenoamide-based route to synthesize new Fe/Se cluster complexes has been investigated. The three-component reaction of PhC(Se)NHCH2Ph, Et3N and Fe3(CO)12 affords the [Et3NH]+ salt of the [(μ-PhCNCH2Ph)Fe2(CO)6(μ-Se)]− cluster anion. The Se-centered cluster anion reacts with PhCH2Br to give (μ-k2C,N-PhCNCH2Ph)Fe2(CO)6(μ-SeCH2Ph) (1). Furthermore, trapping the Se-centered cluster anion with PPh2Cl offers (μ-k2C,N-PhCNCH2Ph)Fe2(CO)6(μ-k2Se,P-SePPh2) (2). Treating the Se-centered cluster anion with CF3CO2H leads to [(μ-k2C,N-PhCNCH2Ph)Fe2(CO)6]2(μ4-Se2) (3) and [(μ-k2C,N-PhCNCH2Ph)Fe2(CO)6(μ4-Se)]2Fe2(CO)6 (4). More interestingly, reacting with Fe3(CO)12 forms the [Et3NH]+ salt of the [(μ-PhCNCH2Ph)Fe2(CO)6(μ4-Se)Fe2(CO)6(μ-CO)]− cluster anion. Treating the μ-CO-containing cluster anion with (1,2-O2C6H4)PCl produces (μ-k2C,N-PhCNCH2Ph)Fe2(CO)6(μ4-Se)Fe2(CO)6(μ-(1,2-O2C6H4)P) (5). All the new cluster complexes have been unequivocally determined by X-ray crystallography and completely characterized by microanalyses, IR, 1H NMR, 13C NMR and 77Se NMR as well as 31P NMR for 2 and 5. Therefore, the reactions of PhC(Se)NHCH2Ph, Et3N and Fe3(CO)12, via the [(μ-PhCNCH2Ph)Fe2(CO)6(μ-Se−)] cluster anion, with electrophiles demonstrate an unprecedented route to new Fe/Se cluster complexes.Novel Fe/Se cluster complexes have been synthesized by the reactions of [Et3NH][(μ-PhCNCH2Ph)Fe2(CO)6(μ-Se)] and [Et3NH][(μ-PhCNCH2Ph)Fe2(CO)6(μ4-Se) Fe2(CO)6(μ-CO)] with electrophiles.

The novel reactions of cluster salts [(μ-RS)Fe2(CO)6(μ4-CS2)Fe2(CO)6][Et3NH] with Ph2PCl, via the insertion of the PPh2 group into an activated C–S bond, afford the unprecedented tetrairon complexes with the unique SCPPh2S ligand which is coordinated to (μ-RS)Fe2(CO)6 and Fe2(CO)6 units in a μ4-k2C:k4S,S′ mode (R = Ph, CH3O2CCH2).

The reaction of Fe3(CO)12 and [NEt4][GCS2] with an electrophile CH3I in THF affords complex Fe2(CO)6(μ-GC(S)SCH3) (G = Ph2PS, 1). The reaction of Fe3(CO)12 with PhCOCH2CS2H and NEt3 forms a red-brown solution of [HNEt3][Fe2(CO)6(μ-GCS2)] identified by IR and ESI-MS (G = PhCOCH2). The reactions of the solution with a series of electrophiles E–X such as CH3I, PhCH2Br and CH2CHCH2Br produce complexes Fe2(CO)6(μ-GC(S)SE) (2, E = CH3; 3, E = CH2Ph; 4, E = CH2CHCH2). In the absence of NEt3, the reaction of Fe3(CO)12 and PhCOCH2CS2H gives complex Fe2(CO)6(μ-S2CCHCOPh) (5). The reaction of GCS2H with NEt3, Fe3(CO)12 and CH3I yields complexes Fe2(CO)6(μ-GC(S)SCH3) (G = 4-MeOC6H4COCH2, 6; G = C5H5FeC5H4COCH2, 7). The reaction of Fe(C5H4COCH2CS2H)2, NEt3 and Fe3(CO)12 with CH3I affords complex Fe[(μ-C5H4COCH2C(S)SCH3)Fe2(CO)6]2 (8). Unlike the above-mentioned cases, the reaction of Fe3(CO)12 and [HNEt3][GCS2] (G = 2-C5H4NNH, 2-C3H2NSNH) with PhCOCl generates the corresponding complexes Fe2(CO)5(μ-k2N,S:k2C-2-C5H4NN(COPh)CS)(μ-k2S-SCOPh) (9) and Fe2(CO)5(μ-k2N,S:k2C-2-C3H2NSN(COPh)CS)(μ-k2S-SCOPh) (10). All new complexes have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy as well as 31P NMR spectroscopy for 1, structures of them have been unequivocally determined by X-ray crystallography.Two new routes to novel Fe/S clusters have been exploited. Reactions of cluster anions of [(μ-GCS2)Fe2(CO)6]− (G = Ph2PS, ArCOCH2) and [(μ-G′NHCS)Fe2(CO)5(μ-S−)] (G′ = 2-C5H4N, 2-C3H2NS) generated from Fe3(CO)12 and heteroally anions of GCS2− and G′NHCS2− in THF with a series of electrophiles afford novel cluster complexes.

Reactions of 1,1′-ferrocenedicarboxylic chloride with 2-aminopyrimidine and 2-aminopyrazine produce organometallic dicarboximides I and II, respectively. They crystallize in space groups Fdd2 and P21/c, respectively. The molecules of I lying on twofold rotation axes are linked into a B-faced sheet by a C–H···O=C hydrogen bond [H····O = 2.46, C···O = 3.163(7) Å and C–H···O = 132°]. The sheets are linked into a layered structure by two types of weak C–H···O=C hydrogen bonds [H···O = 2.71, C···O = 3.340(8) Å and C–H···O = 126°; H···O = 2.69, C···O = 3.303(10) Å and C–H···O = 124°]. The molecules of II are linked into a centrosymmetric R22(12) dimer by a C–H···O hydrogen bond [H···O = 2.40, C···O = 3.321(10) Å and C–H···O = 172°]. The dimers are further packed along the a axis by a C–H···O hydrogen bond [H···O = 2.69, C···O = 3.416(9) Å and C–H···O = 135°] to give an [100] double-chain. The double-chain is packed in the [010] direction by a C–H···O=C hydrogen bond [H···O = 2.69, C···O = 3.532(9) Å and C–H···O = 150°]. Further the intermolecular C–H···N hydrogen bond involving the cyclopentadienyl group as a hydrogen-bond donor and pyrazine N atom as an acceptor [H···O = 2.71, C···N = 3.536(10) Å and C–H···N = 148°] leads to a three-dimensional framework structure.

The title compound (I), C23H23NO3Fe, crystallized in the space group P21/c with Z = 4 whereas the compound (II), C23H23NO4Fe, crystallized in the space group Pbca with Z = 8. In each compound of (I) and (II), in addition to a strong [N–H···O=C] intramolecular hydrogen bond, an infinite one-dimensional chain in the [010] direction is formed by a C–H···O=COEt hydrogen bond for (I) and by C–H···O=COEt and C–H···O=C hydrogen bonds for (II).

The novel reactions of cluster salts [(μ-RS)Fe2(CO)6(μ4-CS2)Fe2(CO)6][Et3NH] with Ph2PCl, via the insertion of the PPh2 group into an activated C–S bond, afford the unprecedented tetrairon complexes with the unique SCPPh2S ligand which is coordinated to (μ-RS)Fe2(CO)6 and Fe2(CO)6 units in a μ4-k2C:k4S,S′ mode (R = Ph, CH3O2CCH2).