Synthesis and Isomerisation Reactions of Tetranuclear and Octanuclear (Carbamato)zinc Complexes

A new series of (diisopropylcarbamato)(oxido)zinc complexes were obtained by innovative synthetic approaches. The (carbamato)zinc clusters [Zn 4 (μ 4 ‐O)(O 2 CN i Pr 2 ) 6 ] ( 1 ) and [Zn 8 (μ 4 ‐O) 2 (O 2 CN i Pr 2 ) 12 ] ( 2 ) were synthesised by an identical reaction procedure involving protolysis of ZnEt 2 with i Pr 2 NH/CO 2 and followed by stoichiometric hydrolysis. Recrystallisation of the reaction product from nitrile solvents yielded the tetrazinc complex 1 . Conversely, recrystallisation from alkane solvents yielded crystals of the octazinc complex 2 . The two structural isomers were readily interconverted simply by recrystallisation from the appropriate solvent. Both complexes were structurally characterised by X‐ray crystallography. The tetrazinc complex 1 has the quintessential basic zinc acetate type structure. Its dimer, the octazinc complex 2 is a new derivative of the [M 8 (μ 4 ‐O) 2 (O 2 CN i Pr 2 ) 12 ] class, examples of which are known for all other first‐row transition metals. The solution chemistry was investigated using variable‐temperature NMR spectroscopy and ESI‐MS. The new synthetic approach offers a route to other similar complexes. Thus, using Et 2 NH in place of i Pr 2 NH yielded the known complex [Zn 4 (μ 4 ‐O)(O 2 CNEt 2 ) 6 ] ( 3 ).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)