Abstract
A homologous series of N‐acylcyanamides of the formula R~2~N−[C(NMe~2~)=N]~n~−C(NMe~2~)=O with n = 1−3 has been prepared among similar amino‐substituted N‐acyl‐oligonitriles by treatment of guanidine 4 with carbamoyl chloride 5 yielding compound 6 (n = 1) and by ring opening of 1,3,5‐oxadiazinium salts 7 with morpholine (8) to give compounds 9 (n = 2) or with guanidine 4 to give compounds 10 (n = 3). The all‐dimethylamino‐substituted compound 10d reacts with ZnCl~2~ to yield a six‐membered chelate complex 10d·ZnCl~2~. The molecular structures of 9e,f, 10a−d and 10d·ZnCl~2~ have been elucidated by X‐ray crystallography and partly by DFT calculations. They deviate strongly from planarity with some examples showing helical structures. From the calculations, 10d is predicted to be a rather strong neutral base. One or two oxidation peaks, depending on the chain length, were observed by cyclic voltammetry. For the most extended derivative 10d a first oxidation potential of 1.12 V was measured. The molecular first hyperpolarizablities β^0^ were determined by hyper‐Rayleigh scattering (HRS) measurements. The β^0^ values increase with chain length and reach 5×10^−30^ esu for the longest derivative 10d. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)