Nickel complexes tertiary arsines

The number of nickel(U) complexes with mono-, bi- and poly-dentate ligands containing tertiary phosphines as a donor group is very large and increases day by day while complexes with tertiary arsines are less numerous and those with stibines are rarer still. The number of nickel(II) complexes with mixed donor ligands containing N, O and S donor atoms besides P or As is also very large. 

Unlike the tertiary phosphine and arsine oxides which form a variety of nickel complexes with peculiar properties, tertiary arsine sulfides and, particularly, tertiary phosphine sulfides... 

The iron compound readily sublimes and yields well-formed, black lustrous crystals. The cobalt complex will also readily sublime, but dependent upon the temperature at which the crystals are formed, they can be either black or brown in color. The crystal structures of both the cobalt and iron complexes have been determined.3 The nickel complex sublimes only in small amounts with difficulty. All three complexes are unstable to air and water, and the nickel complex readily undergoes thermal decomposition above 100°C. All three compounds will also readily form complexes with a variety of donor ligands such as tertiary arsines or phosphines. The nickel compound usually forms 2 1 adducts such as [(C6HS )3P]2Ni(NO)I, while the iron and cobalt complexes often undergo disproportionation.5... 

Although trialkyl- and triarylbismuthines are much weaker donors than the corresponding phosphoms, arsenic, and antimony compounds, they have nevertheless been employed to a considerable extent as ligands in transition metal complexes. The metals coordinated to the bismuth in these complexes include chromium (72—77), cobalt (78,79), iridium (80), iron (77,81,82), manganese (83,84), molybdenum (72,75—77,85—89), nickel (75,79,90,91), niobium (92), rhodium (93,94), silver (95—97), tungsten (72,75—77,87,89), uranium (98), and vanadium (99). The coordination compounds formed from tertiary bismuthines are less stable than those formed from tertiary phosphines, arsines, or stibines. 

Nickel(I) complexes are far less numerous than those of nickel(0). Like nickel(0) complexes, nickel(I) complexes are generally obtained with ligands having -acceptor capability. Most complexes of nickel(I) which have been isolated as solids contain tertiary phosphines (or arsines) as ligands and are sufficiently stable in the absence of air to allow them to be studied with several physicochemical techniques. 

Table 22 Molecular Parameters for some Nickel(I) Complexes with Tertiary Phosphines and Arsines...

A large number of nickel(II) complexes with bidentate tertiary phosphines and arsines have been prepared and characterized since the initial reports on o-phenylenebisdimethylarsine and 1,2-bisdiphenylphosphinoethane (Table 64 XVIII, III) by Chatt and Mann,1267 and Wymore and Bailar126 respectively. The most common diphosphines, diarsines, distibines and mixed donor ligands are collected in Table 64 and selected nickel(II) complexes are reported in Table 65. 

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