Copper(II) adducts with N,N,N′,N′-tetramethylethane-1,2-diamine and attempts to prepare trinuclear derivatives

We have attempted to prepare complexes of the type [M3Cl5(tmen)3][BPh4] (tmen=Me2N(CH2)2NMe2) with M=Cu. Such species are already known for M=Ti, V, Fe, Ni, and Co, but we have been unable to prepare any Cu analogues. The [BPh4]− appears to reduce CuII to CuI and we isolated the known [Cu(tmen)2][CuCl2] from reaction mixtures that contained it. Attempts to obviate this reduction by using a different anion were successful, but no triangulo species were isolated. However, during this work we isolated and structurally characterised [{CuF(BF4)(tmen)}2] and [{Cu(OH)((BF4)(tmen)}2].