This report describes routes to iron dithiolato carbonyls that do not require preformed iron carbonyls. The reaction of FeCl 2 , Zn, and Q 2 S 2 C n H 2n (Q + = Na + , Et 3 NH + ) under an atmosphere of CO affords Fe 2 (S 2 C n H 2n )(CO) 6 (n = 2, 3) in yields >70%. The method was employed to prepare Fe 2 (S 2 C 2 H 4 ) ( 13 CO) 6 . Treatment of these carbonylated mixtures with tertiary phosphines gave the ferrous species Fe 3 (S 2 C 3 H 6 ) 3 (CO) 4 (PR 3 ) 2 , for R = Et, Bu, and Ph. Like the related complex Fe 3 (SPh) 6 (CO) 6 , these compounds consist of a linear arrangement of three conjoined face-shared octahedral centers. Omitting the phosphine but with an excess of dithiolate, we obtained the related mixed-valence triiron species [Fe 3 (S 2 C n H 2n ) 4 (CO) 4 ] − . The highly reducing all-ferrous species [Fe 3 (S 2 C n H 2n ) 4 (CO) 4 ] 2− is implicated as an intermediate in this transformation. Reactive forms of iron, prepared by the method of Rieke, also combined with dithiols under a CO atmosphere to give Fe 2 (S 2 C n H 2n )(CO) 6 in modest yields under mild conditions. Studies on the order of addition indicate that ferrous thiolates are formed prior to the onset of carbonylation. Crystallographic characterization demonstrated that the complexes Fe 3 (S 2 C 3 H 6 ) 3 (CO) 4 (PEt 3 ) 2 and PBnPh 3 [Fe 3 (S 2 C 3 H 6 ) 4 (CO) 4 ] feature high spin ferrous and low spin ferric as the central metal, respectively.

The reaction of [N(PPh(3))(2)][CpCo(CN)(3)] and [Cb*Co(NCMe)(3)]PF(6) (Cb* = C(4)Me(4)) in the presence of K(+) afforded {K subset[CpCo(CN)(3)](4)[Cb*Co](4)}PF(6), [KCo(8)]PF(6). IR, NMR, ESI-MS indicate that [KCo(8)]PF(6) is a high-symmetry molecular box containing a potassium ion at its interior. The analogous heterometallic cage {K subset[Cp*Rh(CN)(3)](4)[Cb*Co](4)}PF(6) ([KRh(4)Co(4)]PF(6)) was prepared similarly via the condensation of K[Cp*Rh(CN)(3)] and [Cb*Co(NCMe)(3)]PF(6). Crystallographic analysis confirmed the structure of [KCo(8)]PF(6). The cyanide ligands are ordered, implying that no Co-CN bonds are broken upon cage formation and ion complexation. Eight Co-CN-Co edges of the box bow inward toward the encapsulated K(+), and the remaining four mu-CN ligands bow outward. MeCN solutions of [KCo(8)](+) and [KRh(4)Co(4)](+) were found to undergo ion exchange with Cs(+) to give [CsCo(8)](+) and [CsRh(4)Co(4)](+), both in quantitative yields. Labeling experiments involving [(MeC5H4)Co(CN)(3)]- demonstrated that Cs(+)-for-K(+) ion exchange is accompanied by significant fragmentation. Ion exchange of NH(4+) with [KCo(8)](+) proceeds to completion in THF solution, but in MeCN solution, the exclusive products were [Cb*Co(NCMe)(3)]PF(6) and the poorly soluble salt NH(4)CpCo(CN)(3). The lability of the NH(4+)-containing cage was also indicated by the rapid exchange of the acidic protons in [NH(4)Co(8)](+). Oxidation of [MCo(8)](+) with 4 equiv of FcPF(6) produced paramagnetic (S = 4/2) [Co(8)](4+), releasing Cs(+) or K(+). The oxidation-induced dissociation of M(+) from the cages is chemically reversed by treatment of [Co(8)](4+) and CsOTf with 4 equiv of Cp(2)Co. Cation recognition by [Co(8)] and [Rh(4)Co(4)] cages was investigated. Electrochemical measurements indicated that E(1/2)(Cs(+))--E(1/2)(K(+)) approximately 0.08 V for [MCo(8)](+).

The first systematic study on the use of tricyanoborates as ligands is presented. The tricyanoborates [RB(CN)3]- (R = oct and Ph) can be prepared by direct cyanation of RBCl2 precursors as well as by thermolysis of the corresponding isocyanides [RB(NC)3]-. The first organo-cyanogallates [RGa(CN)3]- (R = Bu, C6H2-2,4,6-Me3) were prepared from the corresponding dichloride, the structure of Et4N[mesGa(CN3] being confirmed crystallographically. The reaction of equimolar [RB(CN)3]- (R = oct, Ph) and [Cu(MeCN)4]+ afforded two-dimensional polymers [RB(CN)3Cu(NCMe)]. The sheets arise via conjoined hexagonal B3Cu3(CN)6 rings with chair conformations. The reaction of excess [PhB(CN)3]- and [Cu(MeCN)4]+ gives the polymer [K(18-crown-6)]{Cu[PhB(CN)3]2}. Treatment of [PhB(CN)3]- with [Cu(PCy3)2(NCMe)x]PF6 gave the one-dimensional polymer [PhB(CN)3Cu(PCy3)2], wherein two of the three BCN substituents are coordinated.

Condensation of [Cp*Rh(CH(3)NO(2))(n)](2+) and the tricyanoborate [PhB(CN)(3)](-) affords the hexagonal bipyramidal cage [[PhB(CN)(3)](6)[Cp*Rh](6)](6+), demonstrating that tetrahedral tricyanide building blocks can lead to novel cage structures.

The coordination chemistry of the unusual metallo‐ligand Cs⊂[CpCo(CN)3]4[Cp*Ru]3 (Cs⊂Co4Ru3) is described with attention to the behavior of the ligand itself, its binding to Lewis‐acidic metal cations, and its ability to stabilize catalytically relevant Ru–PPh3 fragments. A series of tests demonstrate that the “rim” [CpCo(CN)3]– groups in Cs⊂Co4Ru3 are exchangeable. Upon treatment with [(MeC5H4)Co(CN)3]– (Co′) Cs⊂Co4Ru3 undergoes vertex exchange to give Cs⊂Co4–xCo′xRu3. Similarly the cage is degraded by CO. Most convincing, Cs⊂Co4Ru3 reacts with PhNH3OTf to precipitate the polymer PhNH3CpCo(CN)3 and form the molecular box [Cs⊂Co4Ru4]+. Treatment of Cs⊂Co4Ru3 with [M(NCMe)x]PF6 (M = Cu, Ag) gave the Lewis acidic cages {Cs⊂[CpCo(CN)3]4[Cp*Ru]3M(NCMe)}PF6, which reacted with tertiary phosphane ligands to give adducts [Cs⊂Co4Ru3M(PPh3)]PF6. Lewis acidic octahedral vertices were installed using Fe, Ni, and Ru reagents. The boxes [Cs⊂Co4Ru3M(NCMe)3]2+ (M = Ni, Fe) formed readily from the reaction Cs⊂Co4Ru3 with [Ni(NCMe)6](BF4)2 and [Fe(NCMe)6](PF6)2. Displacement of the MeCN ligands gives [Cs⊂Co4Ru3Ni(9‐ane‐S3)](BF4)2. A series of boxes were prepared by the reaction of Cs⊂Co4Ru3 and RuCl2(PPh3)3, RuHCl(PPh3)3, and [(C6H6)Ru(NCMe)3](PF6)2. The derivative of the hydride, [Cs⊂Co4Ru3Ru(NCMe)(PPh3)2](PF6)2, was characterized crystallographically.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)