Tripledecker complexes

AGE965, 86AGE1099, 880M2316). Species /x-h h -(2-benzyl-l,3,4,5-tetramethyl-2,3-dihydro-l,3-diborolyl)(i7 -allyl)(i7" -l,5-hexadiene)dinickel and /x-i7 i7 -[2-(2,4,6-trimethylbenzyl)-l,3,4,5-tetramethyl-2,3-dihydro-l,3-diborolyl](i7 -allyl)(i7" -l,5-hexadiene)dinickel serve as representative tripledecker complexes (01ZN(B)73). 

The complex [PbsfMofCOA I4 has been recently reported (Yong el al., 2005) and exhibits the structure shown below. Does the compound obey the electron-counting rules for clusters If not, where might one seek an explanation of its behavior Consider explicitly tripledecker complexes as well as complications caused by separating the external cluster lone pairs from cluster bonding pairs (see Chapter 2, Problem 12). For your information, the measured distance between the Mo atoms is 3.216 A, whereas twice the covalent radius of Mo is 2.90 A, the Mo-Mo distance in [Mo2(CO)h> 2 is 3.123 A and the Mo-Mo distance in the 27-valence electron tripledecker complex CpMo(r 5-As5)MoCp is 2.764 A. 

In the first member of the series, n = 6, the borane ring is hexagonal and planar allowing an alternate description of the compound as a 24-valence electron tripledecker complex of the type mentioned in Chapter 4 (Figures 4.12 and 4.17). The geometric/electronic mechanism for accommodating a varied electron count in a tripledecker complex can be applied to the n = 7-10 rhenaboranes with a... 

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