Trigonal-planar complexes

C18-0088. Copper forms a trigonal planar complex ion with three chloride ions (. f = 5.0 X 10 ). A... 

Fig. 4. A d10 trigonal-planar complex. is considered to be trans to the X substituents and Lj trans to the Y substituents.

The valence orbitals of a trigonal planar complex can be easily constracted as we have done for the preceding examples. An alternative way to view the construction of the d-block manifold is shown in (18). Just as in the octahedral MLe to square-planar MT4 transformation shown in (15), only one metal d-based MO is affected. The majority of the M-T a antibonding is lost in furthermore, metal... 

Qualitatively draw the crystal field splitting of the d orbitals in a trigonal planar complex ion. (Let the z axis be perpendicular to the plane of the complex.)... 

The trigonal planar complexes of the MX3 type, whether of the lanthanide or of the transition metal series, have a particular significance. In an amendment to the crystal field intensity theory, designed to accommodate the hypersensitive f—f transitions, the addition of the first-rank spherical harmonics, Yim to the ligand field was proposed in order to form, with the dipole operator, an effective quadrupole operator within the 4f shell i). Crystal field potentials of the Yim form are restricted, however, to metal complexes with a permanent dipole moment, that is, to the site symmetries Cpv and their subgroups ), and the proposal does not account for the relatively large oscillator strengths of the quadrupole-allowed d—d or f—f transitions of... 

Trigonal planar complex (17), presumably formed via (CO)5WGeCl2, is prepared through the reaction of GeC with Na2W2(CO)io. 

Earlier we reported the reaction of 1 with Ni(CO)4, in which two carbon monoxide molecules are displaced to yield the tetrahedral complex, (l)2Ni(CO)2 [7]. When bis(cyclooctadiene)nickel is treated with 1 or 2, both cyclooctadiene molecules are lost and the trigonal planar complexes (l) Ni and (2)3Ni are obtained [8]. The stracture of (l)3Ni is shown in Fig. 4. This trigonal structural arrangement for nickel complexes is unusual, but not unprecedented. 

Draw qualitative diagrams for the crystal field splittings in (a) a linear complex ion ML2, (b) a trigonal-planar complex ion ML3, and (c) a trigonal-bipyramidal complex ion ML5. 

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