The reaction between [Pd(C6H3NNR-2, X-5)Cl]2 and phosphines gives [Pd(C6H3NNTo-2,Me-5)Cl(L)] [To = C6H4Me-4, L = PEt3 (1a), PPh2Me (1b)] or trans-[Pd(C6H3N2To-2,Me-5)ClL2] (L = PEt3 (2a), PPh2Me (2b), L2 = bis(diphenylphosphino)methane = dppm (2c)) or trans-[Pd(C6H3N2X-2, R-5)Cl(μ-dppm)]2 (X = Me, R = To (3a); X = H, R = Ph (3b)), depending on the molar ratio of the reagents. Tl(OTf) (OTf = O3SCF3), AgClO4, or AgSbF6 react with 1a,b, 2a, 2c, or 3a to give, variously, [Pd(C6H3NNTo-2,Me-5)(Y)(L)] (L = PEt3, Y = TfO (4a); L = PPh2Me, Y = TfO (4b), ClO4 (4b‘)), trans-[Pd(C6H3N2To-2,Me-5)(OTf)(PEt3)2] (5), [Pd(C6H3N2To-2,Me-5)(η1-dppm)(η2-dppm)]TfO (6), or [Pd(C6H3NNR-2,X-5)(η2-dppm)]Y (X = Me, R = To, Y = TfO (7a)). Complexes [Pd(C6H3NNR-2,X-5)(η2-dppm)]SbF6 (X = Me, R = To (7a‘); X = H, R = Ph (7b)) can be prepared by reacting [Pd(C6H3NNR-2,X-5)Cl]2 with AgSbF6 and dppm. Complex 4b‘ reacts with PPh2Me to give [Pd(C6H3N2To-2,Me-5)(PPh2Me)3]ClO4 (8). Attempts to obtain single crystals of 4a, [Pd(C6H3NNR-2,X-5)(PPh3)(Me2CO)]ClO4, or 7b lead to different products. From 4, an insertion into the Pd−OTf bond of one molecule of water gives [Pd(C6H3NNTo-2,Me-5(OH2···OTf)(PEt3)] (9) while substitution of the acetone molecule by two water molecules occurs in the second case to give [Pd(C6H3NNTo-2,Me-5){(μ3-OH2)(···OClO3)(···OH2)}(PPh3)] (10). Finally, ready oxidation in the air of 7b gives [Pd(C6H4NNPh-2)(η2-dppmO)]SbF6 (11) [dppmO = bis(diphenylphosphino)methane monoxide]. [Pt(PPh3)3] reacts with [Hg(C6H3N2To-2, Me-5)Cl] to give trans-[Pt(C6H3N2To-2,Me-5)Cl(PPh3)2] (12), which in turn reacts with Tl(OTf) to give [Pt(C6H3NNTo-2,Me-5)(PPh3)2]TfO (13). Crystal structures of 2c· 1 / 2 CH 2 Cl 2 , 4b‘, 5, 6, 7a, 9, 10, and 11·2MeOH have been determined.

The ortho-metalated complex (S,S)-[Pd2{κ2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2(μ-Br)2] (1b) can be prepared by refluxing in acetonitrile equimolecular amounts of Pd(OAc)2 and l-phenylalanine methyl ester hydrochloride, followed by addition of an excess of NaBr. Complex 1b reacts with 4-picoline to give the mononuclear derivative (S)-[Pd{κ2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2Br(NC5H4Me-4)] (2), whose crystal structure has been determined by X-ray diffraction. The precursor of 1b, (S,S)-[Pd2{κ2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2(μ-Cl)2] (1a), could not be isolated in a pure form, but it can be used as the starting material for the synthesis of functionalized derivatives of the phenylalanine methyl ester. Thus, CO and RNC (R = Xy, t Bu) insert into the Pd−C bond of 1a to afford, after depalladation, (S)-1-oxo-3-(methoxycarbonyl)-1,2,3,4-tetrahydroisoquinoline (3) and (S)-1-R-3-(methoxycarbonyl)-3,4-dihydroisoquinolinium triflate (R = tBu (4), Xy (5)), respectively. Reaction of complex 1b with bromine or iodine affords trans-(S,S)-[PdBr2{NH2CH(CO2Me)CH2C6H4-X-2}2] (X = Br (6), I (7)), which further reacts with 1,10-phenanthroline (phen) to give [PdBr2(phen)] and (S)-2-X-phenylalanine methyl ester (X = Br (8), I (9)).

Tris-cyclometalated Pt(IV) complexes are reported for the first time. The facial isomers exhibit long-lived 3LC emissions with quantum yields up to 0.49, the highest ever found for Pt(IV) complexes, combined with a strong oxidizing character in the excited state.

AuCl(SMe 2 )] reacts with HCtCR (R ) bpyl ) 2,2′-bipyridine-5-yl (1), phtpyl ) phenyl-4-(2,2′: 6′,2′′-terpyridine-4-yl) (2)) and NEt 3 (1:1:3) to afford the polymers [Au(CtCR)] n (R ) bpyl (3), phtpyl (4)). The new alkyne HCtCphccbpyl (5, phccbpyl ) 4-C 6 H 4 CtCbpyl) has been prepared by Sonogashira coupling of 4-Me 3 SiCtCC 6 H 4 I and 1 followed by desilylation of the resulting alkyne 4-Me 3 SiCtCphccbpyl. The alkynyl Au(I) complexes [Au(CtCR)L] (R ) bpyl, L ) PPh 3 (6), PTol 3 (7, Tol ) 4-MeC 6 H 4 ), PEt 3 (8); R ) phtpyl, L ) XyNC ( 9), PPh 3 (10); R ) phccbpyl, L ) PPh 3 ( 11)) have been prepared by reacting: (1) 3 or 4 with L or (2) the corresponding alkyne 1, 2, or 5 with [Au(acac)(PPh 3 )] (acac ) acetylacetonato). The reaction of 3 or 4 with diphosphines gives [{Au(CtCR)} 2 (µ-Ph 2 P(CH 2 ) x PPh 2 )] (R ) bpyl, x ) 1 (12), 2 (13), 4 (14), 10 (15); R ) phtpyl, x ) 10 ( 16)). ESI mass spectrometric studies show that complexes 12-14 are in equilibrium with the salts [Au 3 (CtCbpyl) 2 (µ-Ph 2 P(CH 2 ) x PPh 2 ) 2 ][Au(CtCbpyl) 2 ], although only when x ) 1 ( 17) was a significant concentration of the salt detected by NMR spectroscopy and isolated. The anionic complexes PPN[Au(CtCR) 2 ] (R ) bpyl ( 18), phtpyl ( 19), or phccbpyl ( 20)) have been prepared by reaction of the corresponding alkynes with PPN[Au(acac) 2 ]. Complexes 6, 10, 13, 14, 17, and 18 have been characterized by single-crystal X-ray diffraction studies. The alkynyl complexes are luminescent at room temperature, displaying dual emissions.

The palladated primary amines [Pd{C 6 H 3 CH 2 NH 2 -2-X-5}(µ-Br)] 2 [X ) H (1a), OMe (1b), NO 2 (1c), F (1d)] react with isocyanides (Pd:RNC ) 1:1) to give [Pd{C 6 When XyNC reacts with 1a (Pd:RNC ) 1:2) or with 2a (Pd:RNC ) 1:1), the complex [Pd{(CdNXy)C 6 H 4 CH 2 NH 2 -2}(XyNC)Br] (4a) is obtained. The reactions of complexes 1 with isocyanides in the ratio Pd:RNC ) 1:3 lead to Pd(I) complexes [Pd 2 Br 2 L 4 ] [L ) XyNC (5); L ) t Bu ( 6)]. On the basis of NMR data we propose the following reaction pathway for this reduction process: (1) formation of the corresponding monomer 2 or 3, (2) insertion of one molecule of the isocyanide into the Pd-C bond of 2 or 3 to give [Pd{(CdNR)C 6 H 3 CH 2 NH 2 -2-X-5}(RNC)Br], (3) cleavage of the N-Pd bond and coordination of a new isocyanide molecule to give complexes [Pd{(CdNR)C 6 H 3 CH 2 NH 2 -2-X-5}(RNC) 2 Br][detected in solution for R ) Xy, X ) H (7a) and isolated as an acetylated derivative of this complex [Pd{(CdNXy)C 6 H 4 CH 2 NHC(O)Me-2}(XyNC) 2 Br] (8a)], and (4) decomposition of these complexes to give 5 or 6. The organic product of these reactions was not identified. By refluxing mixtures of complexes 1 with RNC and TlOTf (Pd:RNC:TfO ) 1:1:1) the corresponding isoindolinium triflates 9‚OTf [R ) Xy, X ) H (9a‚OTf), OMe (9b‚OTf), F (9d‚OTf)] or 10‚OTf [R ) t Bu, X ) H (10a‚OTf), OMe (10b‚OTf), F (10d‚OTf)] were isolated and characterized. A mechanism of formation of these isoindolinium triflates is proposed. When the reaction between 1a and XyNC (Pd:RNC ) 1:1) was carried out in refluxing toluene in the absence of TlOTf, or when 2a was refluxed in toluene, an insertion of the isocyanide occurs in both cases to give [Pd{(CdNXy)C 6 H 4 CH 2 NH 2 -2}Br] 2 (11). If 1a or 2a is reacted with XyNC (Pd:RNC ) 1:1.25 or 1:0.25, respectively), the complex [PdBr 2 {2-(XyNH)-isoindole} 2 ] (12) is formed. A proposal for the reaction pathway of this process is discussed. The crystal structures of 3d, 9a‚OTf, and 12 have been determined.

Reaction of the iminophosphorane Ph3PNC6H4Me-4 (1a) with Hg(OAc)2 and LiCl gives the mercurated iminophosphorane [Hg{C6H3(NPPh3)-2-Me-5}Cl] (2). The latter reacts with NaBr to give [Hg{C6H3(NPPh3)-2-Me-5}Br] (3). 2 reacts with MeC6H4NCO-4 or CX2 (X = O, S) to give [Hg{C6H3(NCNC6H4Me-4‘)-2-Me-5}Cl] (4) or [Hg{C6H3{NCNC6H3(HgCl)-1‘-Me-5‘}-2-Me-5}Cl] (5), respectively. Iminophosphoranes Ph3PNC6H4R-4 (1b) react with Pd(OAc)2 to give the complexes [Pd{κ2-C,N-C6H4(PPh2NC6H4R-4‘)-2}(μ-OAc)]2 (R = Me (6a), MeO (6b)), in which the palladation takes place at one of the phenyl substituents of the PPh3 group. Complex 6b reacts with NaBr or t BuNC to give [Pd{κ2-C,N-C6H4(PPh2NC6H4OMe-4‘)-2}(μ-Br)]2 (7) or [Pd{κ2-C,N-C6H4(PPh2NC6H4OMe-4‘)-2}(OAc)(CN t Bu)] (8), respectively. Complexes 6a,b react with NaClO4 and N,N,N ‘,N ‘-tetramethylethylenediamine (tmeda), yielding [Pd{κ2-C,N-C6H4(PPh2NC6H4R-4‘)-2}(tmeda)]ClO4 (R = Me (9a), MeO (9b)). The compound Ph3PNC6H4I-2 (1c) adds oxidatively to [Pd2(dba)3]·dba (dba = dibenzylideneacetone) in the presence of tmeda, resulting in the formation of complex [Pd{C6H4(NPPh3)-2}I(tmeda)] (10). The complex 10 reacts (i) with PPh3 and TlOTf (TfO = CF3SO3) to give [Pd{C6H4(NPPh3)-2}(tmeda)(PPh3)]TfO (11·TfO), (ii) with XyNC (Xy = C6H3Me-2,6) (1:3 molar ratio) to give [Pd{κ2-C,N-C(NXy)C6H4(NPPh3)-2}I(CNXy)] (12), and (iii) with XyNC and TlOTf (1:3:1) to give [Pd{κ2-C,N-C(NXy)C6H4(NPPh3)-2}(CNXy)2]TfO (13). An excess of the alkyne MeO2CC⋮CCO2Me reacts with 10 and AgClO4 (4:1:1) to give the inserted compound [Pd{κ2-C,N-C(CO2Me)C(CO2Me)C6H4(NPPh3)-2}(tmeda)]ClO4 (14·ClO4). The crystal structures of 2, 6a·CH2Cl2, 9a, 11·TfO, and 14·ClO4 have been determined by X-ray diffraction studies.

The effects of diphosphine flexibility and bite angle on the structures and luminescence properties of Au(I) complexes have been investigated. A range of diphosphines based on heteroaromatic backbones [bis(2-diphenylphosphino)phenylether (dpephos), 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (xantphos), and 4,6-bis(diphenylphosphino)dibenzofuran (dbfphos)] has been used to prepare mono- and digold derivatives. A clear relationship between the presence of aurophilic contacts and the emission properties of dinuclear complexes has been observed, with one of the complexes studied, [Au(2)Cl(2)(micro-xantphos)], exhibiting luminescence thermochromism.

Cyclometalation of 3-(2-naphthyl)-d-alanine methyl ester is achieved by reacting the corresponding hydrochloride salt and Pd(OAc)2 in a 1:1 molar ratio (acetonitrile, room temperature, 6 days). Although the chloro-bridged dimer (A) cannot be isolated in a pure form, addition of RNC to the reaction mixture affords the mononuclear derivatives (R)-[Pd{κ2(C,N)-C10H6CH2CH(CO2Me)NH2-2}Cl(CNR)] (R = tBu (1a- t Bu), Xy (C6H3Me2-2,6) (1a-Xy)). Similar complexes (S)-[Pd{κ2(C,N)-C8H5N(CH2CH(CO2Me)NH2)-2}Cl(CNR)] (R = tBu (1b- t Bu), Xy (1b-Xy)) are prepared from RNC and a previously reported cyclometalated derivative of l-tryptophan methyl ester, (S,S)-[Pd2{κ2(C,N)-C8H5N(CH2CH(CO2Me)NH2)-2}2(μ-Cl)2] (B). Compound 1b-Xy reacts with XyNC to give the iminoacyl complex (S)-[Pd{κ2(C,N)-C(NXy)C8H5N(CH2CH(CO2Me)NH2)-2}Cl(CNXy)] (2b), whose crystal structure has been determined by X-ray diffraction studies. The cyclopalladated dimer B or those containing phenethylamine (C) or phentermine (D; see Chart ) reacts with RNC (R = tBu, Xy) in refluxing chloroform or toluene to render, depending on the reaction conditions, the cyclic amidines (3c- t Bu, 3d-Xy) or the amidinium salts (4b- t Bu, 4c- t Bu, 4c-Xy, 4d- t Bu, 4d-Xy). The amidines 3a- t Bu and 3a-Xy and the amidinium salts 4a- t Bu and 4a-Xy are synthesized from complexes 1a- t Bu and 1a-Xy. When D reacts with isothiocyanates RNCS (R = Me, To (C6H4Me-4)), the cyclic amidinium salts 4d-Me and 4d-To are isolated. Amidinium triflates derived from phentermine with an aryl substituent at the exocyclic nitrogen atom (4d-Xy, 4d-To) present E/Z isomerism in CHCl3 or CH2Cl2 solution. CO reacts with A−D to give, after depalladation, the corresponding lactams: (R)-1-oxo-3-(methoxycarbonyl)-1,2,3,4-tetrahydrobenzo[g]isoquinoline (5a), (S)-1-oxo-3-(methoxycarbonyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (5b), 1-oxo-1,2,3,4-tetrahydroisoquinoline (5c), and 1-oxo-3,3-dimethyl-1,2,3,4-tetrahydroisoquinoline (5d). The crystal structures of compounds 4b- t Bu, 4c- t Bu, 4d- t Bu, 4d-Xy, 4d-Me, 4d-To, and 5a−d have been determined by X-ray diffraction studies.