Complexes of diamagnetic

The proton NMR data for other OMPA complexes of diamagnetic metal ions are also included in Table III for comparison. The increasing order of OMPA— metal ion interaction as indicated by NMR shifts is... 

In the first situation, the proton NMR spectra of complexes of diamagnetic metal ions which have negligible abundances of isotopes with spin one-half are simple and exhibit two sharp peaks corresponding to the ethylenic and to the acetate protons. The complex should exist in various stages of... 

EXCHANGE KINETICS OF COMPLEXES OF DIAMAGNETIC CATIONS WITH NONAMETHYLIMIDODIPHOSPHORAMIDE, STUDIED BY N.M.R. 

The neutral complexes of chromium, molybdenum, tungsten, and vanadium are six-coordinate and the CO molecules are arranged about the metal in an octahedral configuration as shown in stmcture (3). Vanadium carbonyl possesses an unpaired electron and would be expected to form a metal—metal bond. Steric hindrance may prevent dimerization. The other hexacarbonyls are diamagnetic. 

Complexes of and The effect of complexation on the splitting of d orbitals is much greater in the case of second- and third-than for first-row transition elements, and the associated effects already noted for Ni are even more marked for Pd and Pi as a result, their complexes are, with rare exceptions, diamagnetic and the vast majority are planar also. Not many complexes are formed with O-donor ligands but, of the few that arc, [M(H20)4] ions, and the polymeric anhydrous acetates [Pd(02CMe)2l3 and [Pt(02CMc)2]4 (Fig. 27.10), are the most... 

In the Fe(CN)64- ion shown at the left, Ao is so large that the six 3d electrons of the Fe2+ ion pair up in the lower energy orbitals. In this way, the Fe2+ ion achieves its most stable (lowest energy) electronic structure. The complex is diamagnetic, with no unpaired electrons. 

Fluoride complexes of silver(III) are exemplified by the purple-red Cs2KAgF6 (elpasolite structure, octahedral Ag3+ paramagnetic with /x = 2.6/ub). Yellow MAgF4 (M = Na, Rb, K) and XeF AgF4 are diamagnetic and probably square planar [65],... 

The nickel(II) dithiocarbamate complexes are neutral, water-insoluble, usually square-planar, species, and they have been studied extensively by a range of physical techniques. The usual methods for the synthesis of dithiocarbamate complexes have been employed in the case of Ni(II), Pd(II), and Pt(II). In addition, McCormick and co-workers (330,332) found that CS2 inserted into the Ni-N bonds of [Ni(aziri-dine)4P+, [Nilaziridinelgf, and [Ni(2-methylaziridine)4] to afford dithiocarbamate complexes. The diamagnetic products are probably planar, but they have properties typical of dithiocarbamate complexes, and IR- and electronic-spectral measurements suggested that they may be examples of N,S-, rather than S,S-, bonded dithiocarbamates. The S,S-bonded complexes are however, obtained, by a slow rearrangement in methanol. The optically active lV-alkyl-iV(a-phenethyl)dithio-carbamates of Ni(II), Pd(II), and Cu(II) (XXIV) have been synthesized, and the optical activity was found to be related to the anisotropy of the charge-transfer transitions (332). 

Six-coordinate organoiron porphyrin nitrosyl complexes, Fe(Por)(R)(NO), were prepared from Fe(Por)R (Por = OEP or TPP R = Me, n-Bu, aryl) with NO gas. The NMR chemical shifts were typical of diamagnetic complexes, and the oxidation state of iron was assigned as iron(ll). ... 

Pesek, J.J. and Mason, W.R. (1979) Carbon-13 magnetic resonance spectra of diamagnetic cyano complexes. Inorganic Chemistry, 18, 924—928. 

Iron(II) complexes are often included in studies when complexes are prepared from a large number of different metal ions. 2-formylpyridine thiosemicarbazone, 5, forms brown [Fe(5)2A2] (A = Cl, Br) when prepared in ethanol and [Fe(5-H)2] from aqueous alcohol solution [156], All of these complexes are diamagnetic. The resonance Raman and infrared spectra of [Fe(5-H)2] were examined in detail [130] and coordination occurs via the pyridyl nitrogen, azomethine nitrogen and thiol sulfur. There is appreciable d-d sulfur-to-iron(II) Jt-bonding. Solution studies of iron(II) complexes of some 5-substituted-2-formylpyridine thiosemicarbazones have been reported [157], but no solids... 

Formylthiophene thiosemicarbazone, 26, forms nickelfll) complexes of stoichiometry of [Ni(26)2]A2, [Ni(26)A2], Ni(26-H)A, and [Ni(26-H)2] where A = Cl, Br, I, NCS etc. [211]. Except when A = NCS in the first two types of complexes, the rest are diamagnetic and planar. The thiosemicarbazone moiety bonds NS, but there is no indication whether the Ni(26-H)A complexes are dimeric, or the thiophene sulfur completes the coordination sphere, which is less likely. 

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