Projects per year
Abstract
The known complex [Ni(medpt)(η-1NO2) (η2-ONO)] 1 (medpt = 3,3′-diamino-N-methyldipropylamine) crystallises in the monoclinic space group P21/m with 1.5 molecules in the asymmetric unit with two different η1-NO ligand environments in the crystal structure. At 298 K the molecule (A) sitting in a general crystallographic site displays a mixture of isomers, 78% of the η1-NO isomer and 22% of an endo-nitrito- (η1-ONO) form. The molecule (B) sitting on a crystallographic mirror plane adopts the η-1NO isomeric form exclusively. However, a variable temperature crystallographic study showed that the two isomers were in equilibrium and upon cooling to 150 K the η1-ONO isomer converted completely to the η1- NO isomer, so that both independent molecules in the asymmetric unit were 100% in the η1-NO form. A kinetic analysis of the equilibrium afforded values of ΔH = -9.6 (±0.4) kJ mol∼1, ΔS = -21.5 (±1.8) J K∼1 mol and EA = -1.6 (±0.05) kJ mol∼1. Photoirradiation of single crystals of1 with 400 nm light, at 100 K, resulted in partial isomerisation of the η1-NO2 isomer to the metastable η-1ONO isomer, with 89% for molecule (A), and 32% for molecule (B). The crystallographic space group also reduced in symmetry to P21 with Z′ = 3. The metastable state existed up to a temperature of 150 K above which temperature it reverted to the ground state. An analysis of the crystal packing in the ground and metastable states suggests that hydrogen bonding is responsible for the difference in the conversion between molecules (A) and (B).
Original language | English |
---|---|
Pages (from-to) | 8263-8271 |
Number of pages | 9 |
Journal | CrystEngComm |
Volume | 16 |
Issue number | 35 |
Early online date | 20 Jun 2014 |
DOIs | |
Publication status | Published - 21 Aug 2014 |
Fingerprint
Dive into the research topics of 'Thermal and photochemical control of nitro-nitrito linkage isomerism in single-crystals of [Ni(medpt)(NO2)(η2-ONO)]'. Together they form a unique fingerprint.Projects
- 3 Finished
-
Applying Long-Lived Metastable States in Switchable Functionality via Kinetic Control of Molecular Assembly
Raithby, P., Burrows, A., Carbery, D., Marken, F., Parker, S., Walsh, A. & Wilson, C.
Engineering and Physical Sciences Research Council
1/11/12 → 30/04/18
Project: Research council
-
Dynamic Structural Science at the RC@H
Engineering and Physical Sciences Research Council
1/03/11 → 31/08/16
Project: Research council
-
NON-AMBIENT STUDIES ON OPTO-ELECTRONIC MATIERALS
Engineering and Physical Sciences Research Council
1/10/08 → 30/09/12
Project: Research council