Efficient Syntheses of the Complete Set of Compounds [{(OC)5M}6E6]2− (M = Cr, Mo, W; E = Ge, Sn) − Structure and Redox Behaviour of the Octahedral Clusters [Ge6]2− and [Sn6]2−

Thecloso-[Sn9M(CO)3]4− Zintl Ion Clusters where M=Cr, Mo, W: Two Structural Isomers and Their Dynamic Behavior

“…More recently, we have shown that nido- Sn 9 4À reacts with [Nb(h-C 7 H 8 ) 2 ] to give [(h-C 7 H 8 )Nb(cyclo-Sn 6 )Nb(h-C 7 H 8 )] 2À that contains two-center two-electron bonds. [26] This complex and closo- [Sn 6 {Cr(CO) 5 } 6 ] 2À are static on the NMR timescale, [25] as expected, and show one-bond SnÀSn coupling constants significantly larger that those of nido- Sn 9 4À . [12,15] The first metallated Zintl ion, a Sn 9 4À ÀPt(PPh 3 ) x complex characterized by 119 Sn NMR spectroscopy, was detected by Rudolph and co-workers in a reaction between nido- Sn 9 4À and [Pt(PPh 3 ) 4 ].…”

“…Previous studies on the [(h-C 7 H 8 )Nb(cyclo-Sn 6 )Nb(h-C 7 H 8 )] 2À [26] and closo- [Sn 6 {Cr(CO) 5 } 6 ] 2À [25] ions showed static behavior as expected based on the rigid structure types. In contrast, the nido-Sn 9 4À ion is highly fluxional due to a lowenergy exchange process requiring little atomic reorganization (see Scheme 1).…”

“…[12,15,27] However, the one-bond couplings for 1 ± 3 are less than those of the static closo-Sn 6 2À ions of the [{M(CO) 5 } 6 Sn 6 ] 2À complexes ( 1 J( 119 Sn, 117 Sn) 1740 ± 1848 Hz) [25] and the [(h-C 7 H 8 )Nb-(cyclo-Sn 6 )Nb(h-C 7 H 8 )] 2À ion ( 1 J( 119 Sn, 117 Sn) 1975 Hz). [26] Further studies on these and other metallated polystannides are in progress.…”

“…[22] Metallated polystannides have been prepared by various means and include the complexes closo- [Sn 9 Cr(CO) 3 ] 4À [23] and closo- [Sn 6 {Cr(CO) 5 } 6 ] 2À . [24,25] The Cr atom in the former caps the open square face of nido- Sn 9 4À (see bold lines in I) to form a 10-atom 22-electron closo-cluster, whereas the {Cr(CO) 5 } fragments of the latter are exopolyhedral groups on the octahedral closo-Sn 6 2À core. More recently, we have shown that nido- Sn 9 4À reacts with [Nb(h-C 7 H 8 ) 2 ] to give [(h-C 7 H 8 )Nb(cyclo-Sn 6 )Nb(h-C 7 H 8 )] 2À that contains two-center two-electron bonds.…”

“…Since Sn (9) does not get involved in the exchange process, its coupling constants are more akin to those in the static Sn 6 2À ion. [25] The solid-state infrared data for compounds 1 ± 3 are given in the Experimental Section and in Table 4 in the Supporting Information. The carbonyl regions of the spectra are characterized by the familiar a 1 e bands associated with the virtual C 3v symmetry of the {M(CO) 3 } fragments.…”