Matrix Jahn-Teller distortion

V(CO)e generated by cocondensing presynthesized V(CO)6 with N2 at 10 K has been observed (44, 45). As suggested in a metal-atom study (125), the results indicated that a static, Jahn-Teller distortion is present. Matrix MCD also proved useful in confirming the predicted paramagnetism of Fe(CO)4 (45) (produced by photolysis of Fe(CO)5). In addition, matrix MCD was used to detect such paramagnetic species as MnOaCU in the presence of MnOsCl (45). 

An important condition for chiral matrices is that they need to form labile interactions with the substrate in order to facilitate both the recovery of the enantioselec-tively coordinated ligand and the recycling of the chiral matrix. Usually copper(II) complexes have been used[48]. Due to the problems involved in the modeling of Jahn-Teller distorted copper(II) complexes (see Chapter 11 for a detailed discussion on... 

In previous electron spin resonance (ESR) studies of matrix isolated Naj (X, 1) and K3 3, 4), alkali trimers have been shown to be chemically bound and well described both by simple bonding ideas (1, 3) and by the more sophisticated calculations recently employed for Li3 (5), Na3 6) and Kj 7). For the potassium trimer in argon, two distinct ESR spectra are observed 3). An obtuse angled isomer corresponds to one of three static Jahn-Teller distortions from 03 symmetry, and is surprisingly similar to the... 

Jahn-Teller distorted state. ENDOR results of dimeric benzene cation formed after warming in CFCI3 and present in CF3CCI3 at all temperatures indicate that the dimer had a sandwich structure in both matrices. An EPR study of the benzene radical cation in argon matrix generated by fast electron irradiation at 16 K showed favorable stabilization of big state rather than b2g state, in contrast to previous results found in Freon matrices [180]. 

It has been shown [22] that by diagonalizing the bond-bond polarizability matrix, it is possible to ascertain the likely symmetry of distortion (eigenvectors) and the energy gain (eigenvalues, X) due to second-order Jahn—Teller distortion. In fact, the... 

Copper(rV) is rare. It exists in the red CS2CUF5 which is made by fluorinating CsCuCl3 at 520 K the [CuFg] " ion is low-spin and has a Jahn-Teller distorted octahedral structure. Copper(rV) oxide has been prepared in a matrix by vaporizing the metal and co-depositing it with O2 spectroscopic data are consistent with a linear structure, 0=Cu=0. 

Cyclopentadienyl radicals have been known as long-lived species since Ziegler and Schnell reported the pentaphenyl derivative in 1925, and many differently substituted derivatives have been prepared. The ESR spectra of the parent cyclopentadienyl radical 6 as well as a variety of monosubstituted derivatives RC5H4 (R = D, Me, Et, i-Pr, and t-Bu) f were measured in solution. The spectrum of 6 favors a planar Ti-radical with average Dsh symmetry. This radical is expected to exist as an equilibrium mixture of five pairs of C v structures due to Jahn— Teller distortion, with a very low barrier for rearrangement. Above 70 K, all five hydrogen atoms are equivalent in the ESR spectrum, although in matrixes below this temperature the spectrum is more complex, which is ascribed to observation of the Jahn—Teller-distorted C2 spectrum stabilized by the matrix. ... 

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