Iodo(aryl)palladium complexes, [PdI{C 6 H 3 (CF 3 ) 2 -3,5}(N-N)] (N-N ) tmeda, bpy, 4,4′dimethyl-2,2′-bipyridine (Me 2 bpy)), react with AgBF 4 in CH 3 CN, acetone, and THF to yield stable cationic arylpalladium complexes [Pd{C 6 H 3 (CF 3 ) 2 -3,5}(N-N)(solv)]BF 4 . A similar reaction of AgBF 4 with [PdI(C 6 H 3 Me 2 -3,5)(bpy)] in CH 3 CN gives [Pd(C 6 H 3 Me 2 -3,5)(bpy)-(CH 3 CN)]BF 4 . The complex does not change its NMR spectrum for 1 h at room temperature in CD 3 CN but undergoes decomposition upon dissolution in acetone to release 3,3′,5,5′tetramethylbiphenyl. Addition of AgBF 4 to acetone or THF solutions of [PdI(Ar)(bpy)] (Ar ) Ph, C 6 H 3 Me 2 -3,5) and of [PdI(Ar)(Me 2 bpy)] (Ar ) C 6 H 4 OMe-4, C 6 H 3 Me 2 -3,5) does not lead to isolation of the cationic arylpalladium complexes and causes intermolecular coupling of the aryl ligands to yield the corresponding biaryls. The reaction of AgBF 4 with [PdI(C 6 H 3 Me 2 -3,5)(bpy)] in the presence of an excess amount of dimethyl acetylenedicarboxylate (DMAD) in CH 3 CN gives [Pd(CZdCZ-CZdCZ-C 6 H 3 Me 2 -3,5)(bpy)(CH 3 CN)]BF 4 (Z ) COOMe) via insertion of two acetylene molecules into the Pd-aryl bond. A similar reaction in acetone or THF causes insertion of three DMAD molecules into the Pd-aryl bond and cyclization of the formed Pd-(CZdCZ) 3 -Ar group to give the product containing a cyclopentadiene structure in the ligand. [PdI(CZdCZ-C 6 H 3 Me 2 -3,5)(bpy)] reacts with AgBF 4 in CH 3 CN to form a cationic complex, [Pd(CZdCZ-C 6 H 3 Me 2 -3,5)(bpy)(CH 3 CN)]BF 4 . A series of cationic Pd complexes, formed through insertion of one, two, and three alkyne molecules into the Pd-aryl bond, are characterized by X-ray crystallography or NMR spectroscopy. Phenylallene reacts with [PdI(C 6 H 3 Me 2 -3,5)(bpy)] in the presence of AgBF 4 to give [Pd{η 3 -CH 2 C-(C 6 H 3 Me 2 -3,5)CHPh}(bpy)]BF 4 via insertion of the CdC double bond of the allene into the Pd-C bond of the cationic arylpalladium complex. The π-allylpalladium complex crystallizes exclusively in a form with a syn-oriented phenyl substituent but exists in solution as a mixture of the isomers with a syn or anti phenyl substituent.

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PtI(Ph)(cod) (cod ) 1,5-cyclooctadiene) reacts with acetone in the presence of Ag 2 O to give a mixture of Pt(CH 2 COMe)(Ph)(cod) (1), PtPh 2 (cod) (2), and Pt(CH 2 COMe) 2 (cod) (3) in a molar ratio of 61:20:19. Complex 1, having the phenyl and acetonyl ligands, was isolated by recrystallization of the products and characterized by X-ray crystallography. The reaction of AgBF 4 with PtI(Ph)(cod) forms [PtPh(cod)(acetone-d 6 )]BF 4 and does not give a diarylplatinum complex. Thus, Ag 2 O, in the reaction of PtI(Ph)(cod) with acetone, promotes activation of both the Pt-I bond of PtI(Ph)(cod) and a C-H bond of acetone. Heating of 1 in acetone at 50 °C causes its partial disproportionation into 2 and 3 to give a mixture of the above three complexes. An equimolar mixture of 2 and 3 in acetone undergoes conproportionation into 1 at 50 °C to give a mixture of the complexes. The conproportionation is completed in 30 h to form the mixture with [1]:[2]:[3] ) 66:17:17, while the above disproportionation of 1 does not attain equilibrium even after 70 h. The disproportionation and conproportionation of these complexes are observed also in benzene at 50 °C.

An imidazolium salt, containing two aryloxy groups, was prepared as a precursor for the tetradentate dicarbene ligand. The complexation with Mn(OAc) 2 gaVe an air-stable Mn(III) N-heterocyclic carbene complex in moderate yield. The crystal structure of the complex shows a distorted-squarepyramidal structure, in which two carbene carbon atoms and two aryloxy oxygen atoms of the tetradentate carbene ligand occupied the basal plane.

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Diarylplatinum(II) complexes, [Pt(Ar)2(dmso)2] (Ar = C6H3Me2-3,5 (1a), C6H3(CF3)2-3,5 (1b), Ph (1c); dmso = dimethyl sulfoxide) and [Pt{C6H3(CF3)2-3,5}2(NCCH3)2] (2b), were prepared and fully characterized. Heating mixtures of 2-phenylpyridine (PhpyH) with the complexes in solution at 50 °C caused coordination of PhpyH and its cyclometalation accompanied by elimination of arene to produce monoarylplatinum(II) complexes with a solvent ligand, [Pt(Ar)(Phpy)(dmso)] (Ar = C6H3Me2-3,5 (3a), C6H3(CF3)2-3,5 (3b), Ph (3c)) and [Pt{C6H3(CF3)2-3,5}(Phpy)(NCCH3)] (4b). The rate of the reactions decreased in the order 1a > 1c > 2b > 1b. Crystal structures of 3a,c and 1H NMR spectra of the complexes showed that the aryl ligand and phenyl group of the Phpy ligand occupied cis positions. A diarylplatinum complex with a monodentate phenylpyridyl ligand, [Pt(C6H3Me2-3,5)2(CF3PhpyH)(dmso)] (5), was isolated and characterized using X-ray crystallography. The neutral arylplatinum(II) complex 4b underwent exchange of the acetonitrile ligand more easily than the cationic complex, [Pt{C6H3(CF3)2-3,5}(bpy)(NCCH3)]+, because of the C-bonded phenyl group of the Phpy ligand had a greater trans effect than the N-bonded pyridyl group of bpy. Oxidative addition of I2 to 3a,b and 4b readily gave Pt(IV) dimeric complexes with bridging iodo ligands, [(Pt(Ar)(Phpy)I)2(μ-I)2] (Ar = C6H3Me2-3,5 (7a), C6H3(CF3)2-3,5 (7b)). The dimeric structure of 7b was confirmed using X-ray crystallography.

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