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Abstract: Cobalt(III) and rhodium(III) complexes of the series of [MIIICl3−n(P)3+n]n+ (M=Co or Rh; n=0, 1, 2 or 3) have been prepared with the use of 1,1,1-tris(dimethylphosphinomethyl)ethane (tdmme) and mono- or didentate phosphines. The single-crystal X-ray analyses of both series of complexes revealed that the M–P and M–Cl bond lengths were dependent primarily on the strong trans influence of the phosphines, and secondarily on the steric congestion around the metal center resulting from the coordination of several phosphine groups. In fact, the M–P(tdmme) bonds became longer in the order of [MCl3(tdmme)]<[MCl2(tdmme)(PMe3)]+<[MCl(tdmme)(dmpe)]2+ (dmpe=1,2-bis(dimethylphosphino)ethane)<[M(tdmme)2]3+ for both CoIII and RhIII series of complexes, while the M–Cl bond lengths were shortened in this order (except for [M(tdmme)2]3+). Such a steric congestion around the metal center can also account for the structural and spectroscopic characteristics of the series of complexes, [MCl(tdmme)(dmpm, dmpe or dmpp)]2+ (dmpm=bis(dimethylphosphino)methane, dmpp=1,3-bis(dimethylphosphino)propane). The X-ray analysis for [CoCl(tdmme)(dmpm or dmpe)](BF4)2 showed that all Co–P bonds in the dmpm complex were shorter by 0.03–0.04 Å than those in the dmpe complex. Furthermore, the first d–d transition energy of the CoIII complexes and the 1JRh–P(tdmme) coupling constants observed for the RhIII complexes indicated an unusual order in the coordination bond strengths of the didentate diphosphines, i.e., dmpm>dmpe>dmpp. [Copyright &y& Elsevier]

A reaction of trans-Na[Co(NO2)2(acac)2] with IM2py(2(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl) in methanol afforded trans-[Co(NO2)2(acac)(IMH2py)](IMH2py=1-hydroxyl-2(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole); one-electron reduction of the N–O radical moiety in IM2py and displacement of one of the two acac ligands with retention of two nitrito ligands in the starting complex during the reaction. This new complex was characterized by UV–Vis, 1H NMR spectra and X-ray analysis. [Copyright &y& Elsevier]

Highlights: [•] This is the first example of cobalt(III) complex containing an anionic (Ph2PO)2BF2 − ligand. [•] This is also a rare example of bis(phosphinito)borate complexes determined by the single-crystal X-ray diffraction analysis. [•] The (Ph2PO)2BF2 − ligand shows a stronger ligand-field strength than Ph2POMe. [ABSTRACT FROM AUTHOR]

The syntheses and characterizations of a series of complexes, [(acac)2Co(ox)Ln(HBpz3)2] (Co(ox)Ln, Ln=Sm to Lu) is reported here. Cobalt(III) complexes, Co(ox)Ln, have been compared with chromium(III) complexes, Cr(ox)Ln due to their analogous features in view of structure and spectroscopy. NIR CD spectrum of [(acac)2Co(ox)Yb(HBpz3)2] is examined in comparison with that of the related complexes to reveal the stereospecific formation with configurational chirality around YbIII ion. [Copyright &y& Elsevier]

Mononuclear and binuclear complexes of Cu(I) with bidentate and quadridentate phosphine-thioether hybrid ligands were successfully isolated for the first time by mixing aqueous copper(II) with each corresponding ligand: the structures of these complexes were analyzed by the X-ray crystallographic method and the synthetic route for these complexes was clarified on the basis of the electrochemical behaviors of these complexes in solution. [Copyright &y& Elsevier]