PMID- 16529474
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20070424
LR  - 20060313
IS  - 0020-1669 (Print)
IS  - 0020-1669 (Linking)
VI  - 45
IP  - 6
DP  - 2006 Mar 20
TI  - Orbital interactions in Fe(II)/Co(III) heterobimetallocenes: single versus double 
      bridge.
PG  - 2531-42
AB  - Ferrocenyl cobaltocenium hexafluorophosphate (1) and ferrocenylene 
      cobaltocenylenium hexafluorophosphate (2) are investigated by a range of 
      spectroscopic methods. Both compounds are diamagnetic, in contrast to an earlier 
      report indicating a temperature-dependent paramagnetism of 2. Electronic 
      absorption spectra of 1 and 2 are presented and fully assigned up to 50 000 
      cm(-1) on the basis of electronic structure (DFT) calculations and spectral 
      comparisons with ferrocene and cobaltocenium. The lowest-energy bands, I, of both 
      1 and 2 correspond to metal-to-metal CT (MMCT) transitions; further 
      intermetallocene charge-transfer bands are identified at higher energy (bands III 
      and V). On the basis of the spectroscopic properties, a trans geometry and a 
      twisted structure are derived for 1 and 2, respectively, in solution. Analysis of 
      the I bands gives orbital mixing coefficients, alpha, electronic-coupling matrix 
      elements, V(AB), and reorganization energies, lambda. Importantly, alpha and 
      V(AB) are larger for 1 than for 2 (0.07 and 1200 cm(-1) vs 0.04 and approximately 
      600 cm(-1), respectively), apparently in contrast to the presence of one bridge 
      in 1 and two bridges in 2. This result is explained in terms of the respective 
      electronic and geometric structures. Reorganization energies are determined to be 
      7600 cm(-1) for 1 and 4600 cm(-1) for 2, in qualitative agreement with the 
      analogous Fe(II)-Fe(III) compounds. The general implications of these findings 
      with respect to the spectroscopic and electron-transfer properties of 
      bimetallocenes are discussed.
FAU - Warratz, Ralf
AU  - Warratz R
AD  - Institut fur Anorganische Chemie, Christian Albrechts Universitat Kiel, Otto Hahn 
      Platz 6/7, D-24098 Kiel, Germany.
FAU - Peters, Gerhard
AU  - Peters G
FAU - Studt, Felix
AU  - Studt F
FAU - Romer, Rene-Hermann
AU  - Romer RH
FAU - Tuczek, Felix
AU  - Tuczek F
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Inorg Chem
JT  - Inorganic chemistry
JID - 0366543
EDAT- 2006/03/15 09:00
MHDA- 2006/03/15 09:01
CRDT- 2006/03/15 09:00
PHST- 2006/03/15 09:00 [pubmed]
PHST- 2006/03/15 09:01 [medline]
PHST- 2006/03/15 09:00 [entrez]
AID - 10.1021/ic051809l [doi]
PST - ppublish
SO  - Inorg Chem. 2006 Mar 20;45(6):2531-42. doi: 10.1021/ic051809l.