37.
The reaction of [(C
3Ph
3)Ni(PPh
3)
2]ClO
4 with P(CH
2CH
2PPh
2)
3(pp
3) and NaBPh
4 yields the [(C
3Ph
3)Ni(pp
3)]BPh
4-complex. After long exposure of the solution of this compound in acetone/butanol to the air a new derivative [(C
3Ph
3)-Ni(pp
2po)]BPh
4· 0.5 C
4H
9OH, where pp
2po is (Ph
2PCH
2CH
2)
2P(CH
2 CH
2POPh
2), is obtained. Complete X-ray analysis has been carried out for the latter complex:
a=18.303 (5);
b=29.445 (6),
c=13.305 (5) Å, β=112.70 (9)°; space group monoclinic,
P2
1/
a, Z=4. Disorder problems were encountered in the refinement of the structure. The best
R is 0.093. One of the arms of the parent pp
3-molecule, not coordinated to the metal, undergoes oxidation. The Ni-atom, coordinated by the three remaining P-atoms of the ligand, is also linked in a roughly η
3-mode to the cyclopropenium ligand. The geometry of the molecule is examined in detail. Extended HMO-calculations were performed to interpret how the variation of P? Ni? P angles affects the bonding between the NiP
3- and C
3H
3-fragments. The conclusion is that the overall energy of the complex may be lowered in spite of a weakening of the Ni-cyclopropenium linkage. Extensions are made to other systems containing a linkage between a metal and a X
3-ring (X=P,As).
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