P-and As-Donor Ligands

Dartiguanave, and M. X. Dartiguanave, Bull. Soc. chim. France, 1972, 87. 

The structure of [Ni(ttas)X2] [ttas = bis-(o-dimethylarsinophenyl)methyl-arsine, X = Cl, Br, I, or SCN] is very sensitive to the nature of X and the solvent. Five-co-ordinate monomers are favoured in polar solvents, whereas hydroxylic solvents favour disproportionation to [Ni(ttas)2] and either NiX - or its solvolysis products. The co-ordination geometry of [Ni(ttas)2Y2] (Y = CIO4, NO3, or I) is not certain.  

Mixed donor ligands. The structures of [Ni(picolate)2],4H20 and [Ni(py-2,6-C02)2],3H20 have been determined and are shown in (162) and (163) 

Chiesi-Villa, C. Guastini, A. Musatti, and M. Nardelli, Gazzetta, 1972, 102, 226. 

Stretching frequencies used to assign the structures. Ni(N03)2 reacts with [Ni(R-salen)2] (R = Et or Pr ) to give trinuclear complexes (165) which contain two pseudo-tetrahedral and one octahedral nickel atoms.  

P- and As-Donor ligands. A series of dimeric PF2NR2(L R = Me or Et) complexes of the type [RhXL2]2 (X = Cl or I) have been prepared via reaction (38).151 The PF2NEt2 derivatives reversibly add a further L to give the five-co-ordinate species 

P- and As-Donor Ligands. The complexes [CoR2(acac)(PR )2] [R = Me, Et, Pr , or Bu PR3 = PEt3, P(Bu )3 PPhMe2, or PPh2Me] were prepared by reactions of Co(acac)3, AlR2(OEt), and PR in ether. The phosphonium and phosphonium-hydrogen derivatives of cyano-complex compounds of Co and Ni have been 

Kujuno, A. Vehara, and R. Tsuchiya, Bull. Chem. Soc. Japan., 1975, 48, 3120. T. Ikariya and A. Yamamoto, Chem. Letters, 1976, 85. 

P- and As-donor ligands. More convenient syntheses have been reported for the diarsine and diphosphine complexes [Rh(L2)2]Cl [L2 = o-phenylenebis-(dimethylarsine), PhMePC2H4PMePh, or Ph2AC2H2APh2 (A = P or As)], via direct treatment of [RhCl(CgHi2)]2 with excess The diars cation 

Q[Au(C6F5)3X] + AgC104 AgCN + Qa04 + Q[(C6F5)3Au( J,-X)Au(C6F5)3] 

Coordination of pentafluorophenyl gold(III) to the two free N-donor atoms in 1,1 -bis(2-pyridylthio)ferrocene leads to the dinuclear complex [ Au(C6F5)3 2 Fc(Spy)2 ] structurally characterized [149]. 

Coordination of an additional metallic fragment to a free donor atom of a bidentate diphosphine, dppm [172, 175], (PPh2)2C=CH2 (vinylidenebis(diphenylpho- 

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M(SCH2CH2S)3] with stereochemistry midway between octahedral and trigonal-prismatic, are known for both Nb and Ta. The pentahalides of these two metals act as Lewis acids and form complexes of the type MX5L with O, S, N, P. and As donor ligands. 

Rather limited information is available on how the nature of R affects the rate of CO insertion, all other factors being constant. A generalization that ethylmetal complexes react faster than the corresponding methyl carbonyls derives from investigations on four systems RIr(CO)2(AsPh3)Cl2 (92), RMn(CO)5 (51), CpFe(CO)2R (98), and CpMo(CO)jR (80). When R = Et the reactions with CO or P and As donor ligands proceed at least 6 times faster than when R = Me. 

Group 1 Complexes of P- and As-Donor Ligands Keith Izod... 

C6H2 (supermesityl, mes ) into the ligand such substituents sterically occlude vacant metal coordination sites and greatly increase the solubility of the complexes in common organic solvents. The subtle variations possible within P- and As-donor ligand complexes of the alkali metals lead to an almost bewildering array of structural types, many of which are not observed in other areas of alkali metal chemistry, and to wide variations in reactivity between complexes. 

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