Fluorophosphines bonding

Fluorophosphates, 16 183 Fluorophosphine complexes with borane, 13 439-444 coordination, 13 41CM14 bonding, in, 13 410-414 with nontransition metal halides, 13 445-447... 

The comparatively simple method of preparation of tetrakis (trifluorophos-phine)nickel-(0) encouraged some scouting experiments on its still unexplored chemistry. Whereas the compound is hydrolytically remarkably stable, it was found to react readily with amines and ammonia with complete aminolysis of the phosphorus-fluorine bonds. Very typical of tetrakis(trifluorophosphine) nickel-(0) and similar fluorophosphine and chlorophosphine complexes of zerovalent nickel is the rapid decomposition with precipitation of elemental nickel by aqueous alkali hydroxide. 

Crystallography of two cationic complexes which result from substitution of chloride in (30) with triphenylphosphine were found to have dissimilar structures. The structure of the hexa-fluorophosphinate is similar to the neutral complexes (C—S bond = 177 pm) while the perchlorate is unusual (C—S bond =168 pm). This shortening of the C—S bond in the perchlorate is accompanied by a lengthening of the M—C bond (15 pm) and is probably due to the influence of the perchlorate ion on crystal packing. The M—S bonds of both types of sulfur compounds are significantly longer than the M—C bonds (9-33 pm) which is consistent with sulfur s longer covalent radius. 

Attempts have been made to record the absorption spectra of radicals produced by flash photolysis of several fluorophosphines and tetrafluorobi-phosphine. Well-resolved spectra were not obtained. Irradiation or thermolysis at 300 °C of tetrafluorobiphosphine in the presence of ethylene leads to tetrafluoroethylenediphosphine. Presumably reaction involves homolysis of the P—P bond to give difluorophosphino radicals. Irradiation of biphosphine disulphides and dioxides in the presence of oxygen gives products derived by initial cleavage of the P—P bond. This hypothesis appears to be substantiated by the observation that (17) is formed on decomposition of (16) in... 

Directly bonded coupling constants (Vpp) for some fluorophosphines and their co-ordination complexes m[M(CO)4P2]... 

III. Fluorophosphines Containing Phosphorus-Carbon Bonds. Alkyl- or Arylfluorophosphines, R PF8 . ... 

VI. Fluorophosphines Containing Phosphorus-Oxygen Bonds (Fluoro phosphites). ... 

Fluorophosphines are tervalent phosphorus compounds containing phosphorus-fluorine bonds and they often show markedly different chemical behavior compared with other halogenophosphines. This article is mainly concerned with recent advances in the chemistry of derivatives of PF 3 of the type PF3 X , with particular reference to (a) synthesis of new structural types, (6) the role of fluorophosphines as ligands, particularly in transition metal complexes, and (c) nuclear magnetic resonance (NMR) studies. 

When the metal carries a more negative charge, e.g., in anions [M(PFg)4] or in fluorophosphine-metal complexes containing strongly donating substituents, there is an increase in the metal phosphorus TT bond which, in turn, decreases the p -d component of the P-F bond. 

In short, although it clearly remains uncertain what relative importance should be attached to the a and 77 contributions of the transition metal-phosphorus bond in metal-phosphine complexes, it is probably not without significance that fluorophosphines mainly stabilize the metal in an electronic configuration which maximizes the number of d electrons,... 

Trifluorophosphine has the highest field chemical shift (Sp) of all the phosphorus trihalides or fluorophosphines R PF3 1 3) and the unexpected order for Sp in the PX3 series (X = halogen) was originally discussed (122) in terms of opposing effects of ionic and double character of the P-X bond. A relationship apparently exists between Sp and the electronegativity of the substituent atom for some RPF2 compounds (R = F, RO-, R2N-), the values being considerably lower for the R2N derivatives than the RO compounds. 

On the other hand, Sheluchenko et al. (301) found no simple correlation between Sp and the inductive effect of the X group for a series of fluorophosphines of the type RPFX (X = OR, NR2, SR, Cl), and while the main criterion for determining the phosphorus shift seems to be the atoms to which phosphorus is bonded, at present there is no quantitative understanding of the P shift data summarized in Tables II-VI. 

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