TY - JOUR AU - Nomura, Mitsushiro AU - Geoffroy, Michel AU - Adkine, Prashant AU - Fourmigué, Marc TI - Neutral, Radical [CpNi(dithiolene)] Complexes with Flexible, Nonplanar Seven-Membered Rings: [CpNi{S2C2S2(CH2)2X}] (X = CH2, CF2, C=CH2, S, C=O) PY - 2006 JF - European Journal of Inorganic Chemistry JA - Eur. J. Inorg. Chem. SN - 1434-1948 VL - 2006 IS - 24 SP - 5012 EP - 5021 L1 - http://www3.interscience.wiley.com/cgi-bin/fulltext/113447923/PDFSTART L2 - http://www3.interscience.wiley.com/cgi-bin/fulltext/113447923/HTMLSTART L3 - http://www3.interscience.wiley.com/cgi-bin/abstract/113447923/ABSTRACT L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref00873.png M3 - 10.1002/ejic.200600649 UR - http://dx.doi.org/10.1002/ejic.200600649 KW - nickel KW - S ligands KW - radicals KW - metallacycles KW - magnetic properties N2 - Neutral, radical [CpNi(dithiolene)] complexes fused with seven-membered rings, formulated as [CpNi{S2C2S2(CH2)2X}] (X = CH2, CF2, C=CH2, S), have been synthesized in 30-60 % yields from the reactions of nickelocene with the corresponding neutral, square-planar, (dithiolene)nickel complexes [Ni{S2C2S2(CH2)2X}2]. [CpNi{S2C2S2(CH2)2X}] (X = C=O) was prepared from nickelocene and [1,3]dithiolo[4,5-b][1,4]dithiepine-2,6-dione under thermal or photochemical conditions. All complexes exhibit reversible oxidation and reduction waves to the cation and anion form, respectively. The terminal groups (X) in the seven-membered ring shift their redox potentials to anodic potentials in the following order: CF2 > C=O > S > C=CH2 > CH2. The singlet EPR responses of [CpNi{S2C2S2(CH2)2(X)}] appear at g ≈ 2.0514-2.0529 in dichloromethane solution at room temperature. An NIR absorption is observed at λmax ≈ 798-848 nm (ε ≈ 1700-2400 sup>-1 cm-1) in dichloromethane solution. The X-ray structures of the five complexes show two-legged piano-stool geometries around the central nickel atom (formally NiIII) and strong distortions from planarity of the seven-membered C2S2(CH2)2X rings. In the solid state, those radical (S = 1/2) species adopt either one-dimensional alternating chain-like motifs (X = CH2, C=CH2, S) or dimeric entities characterized by a singlet-triplet magnetic behavior (X = CF2, C=O). ID - 873 ER -