Nitrato ligands

It is possible that the nitrato complexes [RhX2(N03)(PMePh2)2], prepared by the decidedly hazardous addition of concentrated nitric acid to ethanolic solutions of [RhX2H(PMePh2)2], are also six-coordinate hut the IR spectrum of the nitrato ligand reputedly gave no clue to its dentic-ity.953... 

The IR spectrum of [Ni(H2L)(N03)](N03), where H2L = ethylenedia-mine dioxime derivative of 3-carene, shows that the nitrato ligand is bidentate, with H2L coordinated as an N4 ligand.415 IR bands due to nitrato ligands in cis- and tra w-Pt(amine)2(N03)2, where amine = RNH2 (R = Me, Et, nPr, nBu, Pr, Bu, secBu, lBu) or Me2NH, were all consistent with unidentate coordination.416... 

Mixed Donors. The 4-methylpyridine adduct of bis-[l-(2-thienyl)-4,4,4-trifluoro-butane-l,3-dionato]nickel(ii) is shown to have weaker co-ordination than the nonadduct by X-ray studies. The crystal structure of bis-(8-amino-2-methylquinoline) nitratonickel(ii) nitrate shows that the nitrato ligand is bidentate (66). A kinetic study has been made of nickel(ii) murexide complex formation in DMS0-MeN02- Nickel(ii) complexes of some optically active ethylenediamine-NN -diacetic acid-type polyaminocarboxylic acids have been prepared and solid-state spectra and t.g.a. recorded. N.m.r. temperature dependence for racemization of Ni(edta) ,... 

Recrystallization of the initial product from the reaction of triphenylarsine with Ph2Sn(DMS0)3(N03)2 yields crystals of Sn(N03)(SnPh3)3, the structure of which is illustrated in Figure 21. The central tin atom is five-co-ordinated by three Ph3Sn groups and a symmetrically bidentate nitrato-ligand. "... 

Spectroscopy data was used to distinguish the nitrate binding in each of the compounds. Specifically, [Fe(salen)N03)] displayed the following IR frequencies 1533, 1252, 1015, and 777 cm that were assigned to the bound nitrate ligand. The IR frequencies were isotope sensitive with bands at 1499, 1227, 995, and 769 cm, respectively in the N-nitrate-labeled compounds. Similarly, [Fe(salen)0N02]2 displayed IR bands at 1583, 1283, 1033, and 815 cm, and their respective isotope-sensitive bands at 1454, 1262, 1013, and 801 15). The nitrato ligand is bound to Fe in a bid-... 

N-O distance of 1.16(1) A in the complex (2), where the nitrato ligand is unidentate, the N-O distances are 1.247(8), 1.209(8), and 1.166(8) A, the last being that involved in bonding to the metal. It has therefore been suggested that the canonical structure shown in (2), which would be effective in preventing accumulation of negative charge on the metal, is of major importance in this molecule. 

There are other examples where scandium more closely follows the d-type transition metals (or large trivalent metals of the p-block) than the lanthanides. For instance, SUber and Mioduski (1984) found recently that in aqueous methanol this is the case with Sc " " though not with Y +, which resembles La + in its coordination behavior. Furthermore, scandium strongly prefers octahedral coordination in its inorganic complexes (Valkonen, 1979) the maximum CN appears to be 9, which has been achieved only in the case of compact nitrato ligands (see section 6). This may be compared with the lighter lanthanides where 9 is the most common CN and values up to 12 are not rare (cf., section 1.4.2). 

The cerium magnesium compound (CMN) is best known and because of its magnetic transition it is used for low-temperature calibration. The good quality crystals it forms were investigated by single crystal methods as early as 1963 (Zalkin et al.). The central ion is 12-coordinated by six bidentate nitrato ligands at an average Ce-0(N03) distance of 2.64 A (fig. 79). The divalent metal ions are... 

A large increase in activity, stability, and selectivity was observed when the pivalate ligand (e.g., 6) is exchanged for a nitrato ligand (e.g., 9). For example, while 6 catalyzed the homo-CM of 10-methyl undecenoate with 160 turnovers and 90% Z-selectivity, 9 catalyzed the same transformation with 850 turnovers and >95% Z-selectivity. Similar TONs and selectivities were seen in a variety of other homo-CM reactions. Furthermore, 9 could be manipulated on the bench-top, as opposed to its air-sensitive predecessor 6. 

A symmetrically bidentate nitrato ligand in Fe(TpivPP)(N03), where TpivPP = dianion of a,a,a,a-tetrakis(o-pivalamidophenyl)porphyrin, gives IR bands at 1520, 1250 and 1047... 

The IR spectra of [YL2(N03)2], where L = A-alkylphenothiazines, show that the nitrato ligands are bidentate, with L coordinated via the heterocyclic N and the tertiary nitrogen of the side chain." LaL2(N03)3, where L = Schiff bases from 4-antipyrinecarboxaldehyde and o-, m- or />-anisidine and toluidine, have IR spectra showing unidentate NO3, and bidentate L (via azomethine N and ring carbonyl Several other reports have been made of IR spectra of lanthanide... 

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