The ability of bridging thiophenolate groups (RS -) to transmit magnetic exchange interactions between paramagnetic Ni(II) ions has been examined. Specific attention was paid to complexes with large Ni-SR-Ni angles. For this purpose, dinuclear [Ni2Land trinuclear [Ni3L 2 (OAc)2][BPh4]2 (3), where H2L 1 and H2L 2 represent 24-membered macrocyclic amino-thiophenol ligands, were prepared and fully characterized by IR-and UV-vis spectroscopy, X-ray crystallography, static magnetization M measurements and high-field electron spin resonance (HF-ESR). The dinuclear complex 2 has a central N3Ni2(-S)2(-OAc)Ni2N3 core with a mean Ni-S-Ni angle of 92°. The macrocycle L 2 supports a trinuclear complex 3, with distorted octahedral N2O2S2 and N2O3S coordination environments for one central and two terminal Ni(II) ions, respectively. The Ni-S-Ni angles are at 132.8° and 133.5°. We find that the variation of the bond angles has a very strong impact on the magnetic properties of the Ni complexes. In the case of the Ni2-complex, temperature T and magnetic field B dependencies of M reveal a ferromagnetic coupling J = -29 cm -1 between two Ni(II) ions (H = JS1S2). HF-ESR measurements yield a negative axial magnetic anisotropy (D < 0) which implies a bistable (easy axis) magnetic ground state. In contrast, for the Ni3-complex we find an appreciable antiferromagnetic coupling J' = 97 cm -1 between the Ni(II) ions and a positive axial magnetic anisotropy (D > 0) which implies an easy plane situation.

The macrocyclic complex [Ni2(L)(OAc)]ClO4 (1) adsorbs up to 17 molar equivalents (>270 wt%) of iodine, although it does not exhibit permanent porosity. Vibrational spectroscopic and crystallographic studies reveal that two I2 molecules are captured by means of thiophenolate→I2 charge-transfer interactions, which enable the diffusion and sorption of further I2 molecules in a polyiodide-like network. The efficient sorption and desorption characteristics make this material suitable for accommodation, sensing, and slow release of I2.

[3] Entsprechend wurde in den vergangenen Jahren eine ganze Reihe neuer CT-Komplexe vorgestellt, [4] zumeist Polyhalogenide [5] der leichteren und reaktiveren Halogene. [6,7] Nur selten finden sich darunter Addukte von Alkoholaten und Thiolaten, [8]

The dinuclear nickel complexes [Ni L(μ-O CR)](ClO ) [R=Me (4), R=OMe (6)], where L is a 24-membered macrocyclic N S ligand, react readily with excess I in MeCN solution at 4 °C to form stable mono-(I ) and bis-(I ) charge-transfer (CT) adducts of the type [Ni L(μ-O CR)(I ) ] (n=1 or 2) containing linear RS-I-I linkages. Three new CT compounds, namely, [Ni L(OAc)(I )](I )(I ) (5), [Ni L(O COMe)(I )](I )⋅MeCN (7⋅MeCN), and [Ni L(O COMe)(I ) ](I )⋅MeCN (8⋅MeCN) as well as the triiodide salt [Ni L(OAc)](I ) (9) were synthesized and fully characterized. A common feature of the CT adducts is a polyiodide matrix, which surrounds the individual complex molecules, stabilized by secondary I⋅⋅⋅I interactions with the CT linkages. The scatter in both the RS-I (2.6 to 3.0 Å) and the I-I bond lengths (2.7 to 3.0 Å) is indicative of both a variable strength of the RS →I bond and a varying degree of charge transfer. An analysis of the structural parameters was undertaken accompanied by DFT calculations to quantify the donating ability of the bridging thiolate functions and to shed more light on the bonding in this rare sort of charge-transfer complexes. The stability of the CT complexes and the results of preliminary transport measurements are also reported.

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