We report three self‐assembled iron complexes that comprised an anti‐parallel open form (o‐Lanti), a parallel open form (o‐Lsyn), and a closed form (c‐L) of diarylethene conformers. Under kinetic control, FeII2(o‐Lanti)3 was isolated, which exhibited a dinuclear structure with diamagnetic properties. Under light‐irradiation control, FeII2(c‐L)3 was prepared and exhibited paramagnetism and spin‐crossover behaviour. Under thermodynamic control and in the presence of indispensable [FeIII(Tp*)(CN)3]−, FeII2(o‐Lanti)3 and FeII2(c‐L)3 transformed into tetranuclear FeIII2FeII2(o‐Lsyn)2, which exhibited complete spin‐crossover behaviour at T1/2=353 K.

Reaction of di-2-pyridyl ketone (dpk) with nickel acetate and azide in the presence of potassium tert-butylate as a catalytic base generates the title compound, which contains the largest [Ni(m 1,1 -N 3 )] 6 circles in the discrete ferromagnetically-coupled M II -azide cluster family, and shows an unprecedented in situ cyanomethylation of ketone. (Fig. 1a) as a result of the cyanomethylation of ketone was also obtained.Reaction of Ni(OAc) 2 with di-2-pyridyl ketone (dpk), sodium azide, and potassium tert-butylate (t-BuOK) (1 : 0.5 : 1 : 2 molar ratio) in acetonitrile at room temperature led to a pale green solution from which the block deep green crystals of 1?3MeCN?7H 2 O were isolated.{ One of the most intriguing features regarding the synthesis is the direct structural observation of the C-H bond activation of the acetonitrile; a product of the a-alkylation of acetonitrile, dpkMeCN, was generated in situ by the reaction of acetonitrile and di-2-pyridyl ketone under the mild conditions of ambient temperature and the presence of air. It should be noted that another tetranuclear cluster, 5 was obtained if such a reaction was carried out without potassium tert-butylate, suggesting that the presence of potassium tert-butylate is the key to performing such a ligand reaction. The same product as 1 was prepared under the same reaction conditions except for the use of anhydrous Ni(OAc) 2 instead of Ni(OAc) 2 ?4H 2 O. The acetonitrile and dpk in the synthesis of 1 prefer undergoing an unprecedented reaction (Scheme S1{), different from previously reported phenomena. 6-8Moreover, our synthetic route to b-hydroxy nitriles suggests that it may be potentially useful for the addition of nitrile anions to { Electronic supplementary information (ESI) available: synthesis and X-ray crystallography, figures, ac magnetic susceptibilities and field dependence of 1. See

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