title: Photoactivated linkage isomerism in single crystals of nickel, palladium and platinum di-nitro complexes--a photocrystallographic investigation.
abstract: Low temperature, single crystal photocrystallographic studies have been carried out on four square planar Group 10 complexes [Ni(PEt(3))(2)(NO(2))(2)] 1, [Pd(PPh(3))(2)(NO(2))(2)] 2, [Pd(AsPh(3))(2)(NO(2))(2)] 3 and [Pt(PPh(3))(2)(NO(2))(2)] 4, in which the two nitro groups adopt the trans configuration. Irradiation with UV light, at 100 K, of single crystals of complexes 1-3 photoisomerise from the η(1)-NO(2) nitro form to the η(1)-ONO nitrito form occurred. Complex 1 underwent 25% conversion to the nitrito form before crystal decomposition occurred. 2 and 3 underwent 46% and 39% conversion, respectively, to the nitrito form when a photostationary state was reached. While under the same experimental conditions 4 showed no isomerisation. The photocrystallographic results can be correlated with the results of DFT calculations and with the observed trends in the solution UV/visible absorption spectroscopy obtained for these complexes. The results suggest that while steric factors in the isomerization processes are important there may also be a kinetic effect relating to the lability of the metal involved.
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath, UK.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Warren
authors.forename: Simon K
authors.initials: SK
authors.lastname: Brayshaw
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Hatcher
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Johnson
authors.forename: Stefanie
authors.initials: S
authors.lastname: Schiffers
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Warren
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Teat
authors.forename: John E
authors.initials: JE
authors.lastname: Warren
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Woodall
authors.forename: Paul R
authors.initials: PR
authors.lastname: Raithby