Triple-decker complexes

Triple-decker sandwich complexes, in which the heteroarene rings are simultaneously and equivalently bonded to two transition metal atoms lying opposite to each other, are rare. Jonas has reported 

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Triple-decker complexes with pentaphospholyl cycle between Ru and Fe or Ni atoms and carboranes and carbacycles C H (n = 4-7) as terminal ligands 99IZV1636. 

Similar triple-decker complexes are known, e.g., [(17-p-MeC6H4CHMe2) Ru(i7 -Et2C2B3H3)Ru(i7 VMeC6H4CHMe2)] and [(i7 -Cp)Co(i7 -Et2C2 B3H3)... 

Lanthanides form phthalocyanines PcMX, sandwich-like complexes of the type Pc2M, and triple-decker complexes of the type Pc3M2. 

In a similar fashion, the triple-decker complex dilutetium(III) tris(l,2-naphthalocyanine) was prepared in 55% yield.205... 

The triple-decked Tj -CpFe(PhBC4H3Et)FeCp-T7 complex is formed from 1-phenyl-4,5-dihydroborepine and [T) -CpFe(CO)2l2 by thermal reaction the boraben-zene derivative 77 -CpFe(PhBC5H4Me) also forms. With Mn2(CO), l-phenyl-4,5-dihydroborepine yields the triple-decker complex (CO)3Mn(PhBC4H3Et)Mn(CO)3. The borole complexes described so far are available using stable boroles as reactants. But borole molecules can also be generated from precursers in the course of complexation. 

Semiconducting black polymers characterized as 44 have been prepared via slow heating of triple-decker (allyl)nickel diborolyl triple-decker complexes.44 EXAFS studies reveal an Ni-Ni distance of 3.35 A and a powder conductivity of ca. 10-2 S cm-1. When doped with iodine or oxygen, the conductivity of these polymers... 

Figure 15 A triple-decker complex with a dithiaborane, thiadicarba-n/do-undecaborane.

Figure 15 Crystal structure of the triple-decker complex, (CpCr)2(1,2-C3H6-1,2-C2B4H4). Reproduced by permission of the American Chemical Society from Inorg. Chem. 1998, 37, 608.

Of the pentaphospholide ion only ) -coordination is known, sometimes with additional g -coordination. A characteristic feature is the formation of triple-decker complexes with P5 as the middle deck <94CCR1>. Their electronic structure has been explored <89JA2030>. 

The distortion is even more severe in the triple-decker complex (CpMo)2As4S where the planar middle deck is closer to an allylic Ass group and a separate AsS group rather than an AS4S ring <90IC798>. 

Typical three-electron-donor transition-metal fragments (/2c, 25) are the (i)5-C5Hs)Ni and the (CO)3Co groups, which form mononuclear complexes with 3. However, 3 can also hold two metal moieties donating (1 + 2), (2 + 2), (2 + 3), and (3 + 3) electrons because slightly antibonding orbitals in the triple-decker complexes are then occupied. The planar ligands 5, 6, 7, and 8 with the formal acceptor capacities of 4, S, and 6 electrons should only exist in dinuclear complexes when stabilized by a pair of (2 + 2), (2 + 3), and (3 + 3)-electron-donor moieties (7). 

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