The addition of diethylcyanamide to a tetrahydrofuran solution of lithium dialkylamide LiN(CH(3))(2) or Li NCH(2)CH(2)CH(2) CH(2), Li(PYR), results in the corresponding lithium 1,1,3,3-tetraalkylguanidinate, Li(TAG). The subsequent metathesis reaction of Li(TAG) with CuCl generates hexanuclear copper(I) complexes with the general formula [Cu(mu-TAG)](6), where TAG = DEDMG (1) and DEPYRG (2).