A study is reported on the synthesis, spectroscopic properties, molecular structure, and reaction chemistry of η3-propargyl/allenyl complexes of platinum and palladium of the type [(PPh3)2M(η3-CH2CCR)]+ (M = Pt, R = Ph (1a), Me (1b); M = Pd, R = Ph (2a), Me (2b)). Complexes 1a,b were obtained by each of the following methods:  (i) reaction of trans-(PPh3)2PtBr(η1-CH2C⋮CPh) with AgO3SCF3; (ii) treatment of (PPh3)2Pt(η2-PhC⋮CCH2OMe) with BF3·OEt2; (iii) addition of RC⋮CCH2OS(O)2C6H4Me-p to (PPh3)2Pt(η2-C2H4) in solution. Complexes 2a,b resulted upon (i) abstraction of Br- from trans-(PPh3)2PdBr(η1-CH2C⋮CR)/trans-(PPh3)2PdBr(η1-C(R)CCH2) with AgBF4 and (ii) treatment of Pd2(dba)3·CHCl3 with PPh3 and RC⋮CCH2OS(O)2C6H4Me-p. The structures of 1a(OTf)·CH2Cl2 (Tf = O2SCF3) and 2a(BF4) were determined by X-ray diffraction techniques. Both cationic metal complexes show remarkably similar structures, the salient features being the attachment to the metal of all three propargyl/allenyl carbon atoms of the nonlinear C3 fragment (C(1)−C(2)−C(3) bond angles:  152.2(9)° for 1a, 154.7(5)° for 2a) and the essentially coplanar arrangement of the three carbon, two phosphorus, and platinum or palladium atoms. 1a,b react readily with MeOH and Et2NH to afford the corresponding complexes [(PPh3)2Pt(η3-CH2C(X)CHR)]+ (X = OMe, NEt2); 2a,b behave analogously, except that the reaction with MeOH requires trace amounts of NaOMe or NEt3. 1H and 13C NMR spectroscopic data suggest that the reaction products are best formulated as resonance hybrids of η3-allyl and metallacyclic structures.

No abstract

No abstract

symmetry (neglecting the o-methyl substitutent of the tolyl group). This effect should also be operative for an arsenic analogue, but preparative experiments have so far been unsuccessful, probably owing to a further increase of the radius of the central element, which renders A w A u contacts more difficult.Arylphosphinidene groups RP bridging four metal atoms are not completely unknown in the structural chemistry of metal clusters. A very good example in case is the tetranuclear rhodium(1) complex (Rh4(CO)4[p-P(C,H11)2]4(p4-PC6H1,)) with 4-fold symmetry.28 It should be noted, however, that the openshell configuration of electrons of the Rh(1) centers (a8) suggests metal-metal bonding in classical terms for these clusters, while for gold(1) with its formally closed-shell configuration (Sd'O) such bonding interactions are ruled out, unless a mixing with empty 6s states29 through relativistic contraction of the latter provides a new basis for such bonding contacts. It is thii point which makes (28) Arif, A. M.; Jones, R. A.; Heaton, D. E.; Nunn, C. M.; Stuart, S. T. the title compounds interesting novel species in cluster chemistry, and the almost complete absence of similar phenomena with the neighboring elements platinum and mercury once more distinguishes gold as a unique element. [(C~HS)~PAU]~O+BF~-, 53317-87-6; [PhoPAu]+[BF4]-, 6721 5-70-7; phenyltris[(triphenylphosphine)aurio(I)]phosphonium(+) tetrafluoroborate, 132157-66-5.Supplementary Material Available: For complexes 1 and 2, tables of crystallographic data and anisotropic thermal parameters (12 pages); tables of observed and calculated structure factor amplitudes (122 pages). Ordering information is given on any current masthead page. Protonation of cis-mer-RuH2(CO)(Cyttp) (Cyttp = PhP(CH2CH2CH2PCy2),) with excess HX (X = BF,, 0,SCF3) in benzene/diethyl ether produces air-stable complexes with two weakly coordinated anions, viz., cis-mer-RuX2(CO)(Cyttp) (X = BF,(2), 03SCF3 (3)). A single-crystal X-ray diffraction analysis at 223 K shows that 3 crystallizes in the space group PZ,/c with cell parameters a = 11.712 (2) A, b = 15.338 (2) A, c = 27.072 (3) A, 0 = 98.58 (1)O, Z = 4, V = 4809 (1) A', R = 0.041, and R, = 0.046 for the 7036 intensities with F : > 347:) and the 539 variables. The molecules contain two cis-oriented monodentate O,SCF,-ligands. The structural behavior of 2 and 3 in both CD2C12 and acetone-d6 was investigated by variable-temperature 31P(iH} and I9F(lH} NMR spectroscopies in the range.178-303 K a complex behavior involving species with coordinated and free BF, and 0,SCF; ions was observed. 2 and 3 are useful synthons for a variety of coordination and organometallic complexes. 2 undergoes substitution reactions with acetonitrile and organic isocyanides to afford disubstituted complexes cis-mer-[Ru(CO)L2(Cyttp)] [BF,], (L = MeCN, CNBu-t, CNCy). New Ru-F complexes [Ru(F)(CO)(L)-(Cyttp)][BF4] (L = H20, CO, CNBu-t) have also been synthesized from 2. The absence of fluoride abstraction from triflate and the solubility of 3 in THF render thi...

No abstract