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Physical & Chemical properties

Water solubility

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Description of key information

Study not performed as substance is  hydrolytically unstable

Key value for chemical safety assessment

Additional information

Carrying out water solubility testing of NiL4 in general is not feasible owing to NiL4’s high instability in water and rapid decomposition. We are waiving the water solubility study requirement according to column 2 in Annex VII of REGULATION (EC) No 1907/2006: The study need not to be conducted if the substance is hydrolytically unstable.  Despite the difficult conditions for testing this unstable substance, we can provide reliable weight of evidence to support wavier of this data endpoint. 

Experiments were carried out to establish a water and octanol analytical method for NiL4. The octanol solvent was replaced with acetonitrile because NiL4 was reactive with that solvent.  The stability of NiL4 was investigated in 50/50 (v/v) acetonitrile/water with Ultra Performance Liquid Chromatography. Peaks related to the submission substance decreased in time. NiL4 was highly unstable in water and decomposes rapidly to its ligand tritolyl phosphite (TTP).  Over the 13-hour time period, the area of the Ni(TTP)4 peak had decreased by 99%.  No definitive information is available on the rate at which hydrolysis proceeds as a function of pH since the substance failed the preliminary experiment. It was not technically feasible to carry out the water solubility or octanol-water partition co-efficient studies under the current OECD guidelines.