Che Chi-Ming

SYNTHESIS AND REACTIVITY OF N,N‘-BIS O-(DIPHENYLPHOSPHINO)BENZYLIDENE-2,2‘-DIIMINO-1,1‘-BINAPHTHYLENE (BINAP-P2N2) - CRYSTAL-STRUCTURE OF AG(BINAP-P2N2) BF4

Abstract The condensation of a racemic mixture of 2,2′-diamino-1,1′-binaphthylene with two equivalents of o-(diphenylphosphino)benzaldehyde gives a racemic mixture of N,N′-bis[o-(diphenylphosphino)benzylidene-2,2′-diimino-1,1′-binaphthylene (Binap-P2N2) (I) in good yield. The coordination behaviour of I towards CuI and AgI has been explored. The interaction of I with one equivalent of Cu(Ph3P)2Br and [Cu(CH3CN)4][PF6] in CH2Cl2 gives Cu(Binap-P2N2)Br(II) and [Cu(Binap-P2N2)][PF6] (III) in 60% and 74% yield, respectively. In II the Binap-P2N2 ligand acts as a tridentate chelating agent, with the two phosphino groups and one of the two imino groups coordinated to the Cu, whereas in III it acts in tetradentate chelating mode. A variable temperature 31P{1H} NMR study of II reveals that the coordinated and the uncoordinated imino groups of the tridentate Binap-P2N2 ligand undergo a facile intramolecular exchange even at −55°C. The interaction of I with one equivalent of AgBF4 in CH2Cl2 gives [Ag(Binap-P2N2)][BF4] (IV) in 79% yield. In IV, the Binap-P2N2 ligand acts as a tridentate chelating agent, with the two phosphino groups and one of the two imino groups coordinated to the Ag. The structure of IV has been established by an X-ray diffraction study. The distance between Ag and N(2) is 2.56(1) A, and the non-bonding distance between Ag and N(1) is > 3.0 A.

Binuclear gold(I) complexes with bridging diisocyanides and X-ray structures of [Au(tBuNC)(CN)], [Au2(dmb)(CN)2] and [Au2(tmb)(CN)2] (tmb=2,5-diisocyano-2,5-dimethylhexane; dmb=1,8-diisocyano-p-menthane)

Abstract The synthesis and X-ray crystal structures of [Au( t BuNC)(CN)], [Au 2 (dmb)(CN) 2 ] (dmb = 1,8-diisocyano- p -menthane) and [Au 2 (tmb)(CN) 2 ] (tmb=2,5-diisocyano-2,5-dimethylhexane) are described. [Au( t BuNC)(CN)]: space group Pnma, a =13.437(1), b =6.469(1), c =9.823(1) A, Z =4, R =0.055 for 673 observed Mo Kα data; [Au 2 (dmb)(CN) 2 ]: space group P 2 1 / c, a =7.024(2), b =15.255(2), c =15.565(2) A, β=101.33(2), Z =4, R =0.050 for 2137 observed Mo Kα data; [Au 2 (tmb)(CN) 2 ]: space group Pbcn, a =15.629(3), b =9.222(4), c =22.777(3), Z =8, R =0.036 for 1127 Mo Kα data. The intermolecular Au…Au separations are 3.568, 3.49-3.73 and 3.21 A for crystals of [Au( t BuNC)(CN)], [Au 2 (dmb)(CN) 2 ] and [Au 2 (tmb)(CN) 2 ], respectively. [Au 2 (tmb) 2 ] 2+ and [Au 2 (dmb) 2 ] 2+ have also been synthesized by the reaction of Au(I) with the diisocyanide ligand. Their UV-Vis spectra are compared and discussed.

Synthesis, photophysical properties and X-ray crystal structure of a luminescent osmium(VI)-nitrido complex of bis(diphenylarsino)ethane

Abstract Reaction of [OsVI(N)Cl4]− with bis(diphenylarsino)ethane (AsAs) in acetone gave [OsVI(N)Cl3(AsAs)] isolated as an orange solid. The complex (space group P 1 (No.2), a=11.512(2), b=14.389(2), c=19.138(4) A, α=102.97(1), β=94.84(2), γ=110.24(1)°, V=2852.6(9) A3, Z=4; R=0.062 for 5216 observed Mo Kα data) is a distorted octahedral with three chlorine atoms in a meridional configuration. The measured OsN distances of the two crystallographically independent [OsVI(N)Cl3(AsAs)] molecules are 1.70(1) and 1.66(2) A. The photoluminescent properties of the osmium complex are discussed.

Synthesis, characterization and electrochemistry of phenylimido-rhenium(V) complex of 1,4,7-triazacyclononane (TACN)

Abstract The complex [Re(NPh)(OH)(PPh3)(tacn)]2+ (1) was prepared by reacting [Re(NPh)Cl3(PPh3)2] with tacn (tacn = 1,4,7-triazacyclononane) in CH2Cl2 and has been characterized by X-ray crystal analysis. The ReNPh distance is 1.706(10) A and the ReNPh angle is 170.2(9)°. In acetonitrile, the cyclic voltammogram of 1 shows an irreversible reduction wave at −0.77 V assignable to the reduction of rhenium(V) to rhenium(IV). Complex 1 catalyses alkene oxidation by PhIO.

Synthesis and structure determination of ruthenium and osmium complexes with 2,6-bis-(diphenylphosphinomethyl) pyridine

Abstract2,6-Bis (diphenylphosphinomethyl) pyridine (PNP) reaction with Na2OsCl6 · 6H2O to give the five coordinated, sixteen-electron complex Os (PNP)Cl2. In the presence of formaldehyde, the reaction between Na2OsCl6· 6H2O and PNP proceeds rapidly in boiling ethanol to give the coordinately saturated Os(PNP)Cl2(CO). The IR spectrum of Os(PNP)Cl2(CO) shows a strong absorption band at 1 970 cm−1 assignable tov∞ stretch. PNP reacts with RuCl2(PPh3)3 and RuCl2(DMSO)4 (DMSO=dimethyl sulfoxide) to give Ru(PNP)Cl2 (PPh3) and Ru(PNP)Cl2 (DMSO) respectively. The average Ru−Cl, Ru−P and Ru−N bond distance in Ru(PNP)Cl2(PPh3) determineby X-ray crystallography are 0.242, 0.236 and 0.216 nm, respectively.

Synthesis and spectroscopy of nitridoruthenium (VI) and osmium (VI) porphyrins

Reaction of Ru (4-Cl-TPP) (CO) (MeOH) [4-Cl-TPP = meso-kis (4-chlorophenyl) porphyrinato dianion] with 3-chloroperoxybenzoic acid (m-CPBA) followed by treatment of the mixture with an aqueous ammonia solution afforded the first nitrido ruthenium porphyrin Ru(4-Cl-TPP) (N) (OH). Three new nitrido osmium (VI) porphyrins, Os (Por) (N) (OH) (Por=TPP, TTP, and 4-Cl-TPP), were synthesized from oxidation of Os(Por)(NH3)2 withm-CPBA. All these new complexes were characterized by1H NMR, IR, UV/Visible spectra and elemental analyses. Both nitrido ruthenium (VI) and osmium (VI) porphyrins are diamagnetic. Their pyrrole proton resonances appear at slightly lower fields than those of the corresponding dioxo Ru(VI) and Os(VI) porphyrins. The {ie89-1}, or {ie89-2}, region is obscured by the strong “oxidation state marker” band.