The first lithium-aziridinylamidinates, Li[(C2H4N)C(NR)2]·THF (R = iPr (3), Cy (4); iPr = isopropyl, Cy = cyclohexyl), have been prepared by addition of N-aziridinyllithium, C2H4NLi (2), to either N,N′-diisopropylcarbodiimide or N,N′-dicyclohexylcarbodiimide. The cyclohexyl derivative 4 was crystallised from both diethyl ether (Et2O) and THF to afford the crystalline solvent adducts {Li[(C2H4N)C(NR)2]·S}2 (4: S = THF; 4a: S = Et2O) which were structurally characterised by X-ray diffraction. In the solid state, these lithium-aziridinylamidinates comprise ladder-type dimeric molecular structures.

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The ability of the dinuclear nickel(II) complex [NiII2L(L′)]+, where L2− represents a macrocyclic N6S2 ligand, to coordinate monodentate coligands has been examined. Three complexes with L′ = CH3CN, CH2=CHCN, and (BH3CN)− have been synthesized: [NiII2(L)(NCMe)][BPh4]2 (3), [NiII2(L)(NCCH=CH2)][BPh4]2 (4), and [NiII2(L)(NCBH3)][ClO4] (5). All complexes were characterized by elemental analysis, IR and UV/Vis spectroscopy, and X‐ray crystallography. The complexes were found to be isostructural. Each coligand is bonded in a monodentate fashion to generate a central N3Ni(SR)2NiN4 core structure, with the dithiolate‐bridged NiII ions in square‐pyramidal N3S2 and distorted‐octahedral N4S2 coordination environments, respectively. The charged (BH3CN)− group interacts more strongly with the [Ni2L]2+ fragment than the neutral nitrile ligands as reflected by the Ni–N(nitrile) distances which are significantly longer in 3 and 4 than in 5. An analysis of the temperature‐dependent magnetic susceptibility data for 3 reveals the presence of weak ferromagnetic exchange interactions between the NiII ions with a value for the magnetic exchange coupling constant J of 39 cm−1 (H = −2JS1S2).

The title compound, [Ge2(C8H17N2)4O2], crystallizes with imposed twofold symmetry, which allows the monodentate amidinate ligands to be arranged in a cisoid fashion. The independent Ge—O distances within the central Ge2O2 ring, which is essentially planar (r.m.s. deviation = 0.039 Å), are 1.7797 (8) and 1.8568 (8) Å. The germanium centres adopt a distorted trigonal–bipyramidal geometry, being coordinated by the two O atoms and by one bidentate and one monodentate amidinate ligand (three N atoms). One N-isopropyl group is disordered over two positions; these are mutually exclusive because of ‘collisions’ between symmetry-equivalent methyl groups and thus each has 0.5 occupancy.

The cover picture shows a schematic representation of the procedure used for the determination of the magnetic properties of the macrocyclic dinickel complex [Ni2L(μ‐SCN4Me)]BPh4·2MeCN. On the left, the complex is depicted in the form of its two nickel atoms, their first coordination sphere and the 1‐methyltetrazole‐5‐thiolate coligand as obtained from the crystal structure determination. The found N(3),N(4)‐bridging coordination mode is hitherto unknown for 1‐R‐tetrazole‐5‐thiolates. In addition, theoretical calculations were carried out in order to study the coordination features of the complex. Details are discussed in the article by S. V. Voitekhovich, B. Kersting et al. on p. 5387 f. The authors gratefully acknowledge the DAAD (Leonard‐Euler program) and the Erasmus Mundus program “Advanced Spectroscopy in Chemistry”. Supported by the Deutsche Forschungsgemeinschaft within the Graduate School BuildMoNa.