Ting-Bin Wen

Chemistry of tripodal ligands. Part III.: Copper complexes of tris(benzimidazol-2-ylmethyl)amine and of its N-n-propyl derivative

Abstract The reactions of copper (I or II) salts with ligands Rntb (tris( N -alkylbenzimidazol-2-ylmethyl)amine) gave complexes [Cu(II)(ntb)Cl]Cl·3H 2 O ( 1 ), [Cu(I)(ntb)(PPh 3 )](NO 3 )·1.5H 2 O ( 2 ), [Cu(II)(Prntb)I]Cl ( 3 ) and [Cu(I)(Prntb)I] ( 4 ), depending on the reaction conditions. X-ray single crystal diffraction analyses showed the copper atom to be tetrahedrally coordinated in 2 and 4 , but square pyramidal in 1 and trigonal bipyramidal in 3 . Structural characteristics were revealed for the complexes and compared, and complex 3 was shown to be the best model compound among the four for the active center of blue copper proteins. CV studies showed the electrochemical behaviors of the complexes: 1 has two redox couples, phosphine ligation stabilizes 2 towards redox reactions, while 3 and 4 , with the same cationic formula [Cu(Prntb)I] 1+,0 have very similar complicated redox patterns, indicating the reversibility of the two species. IR and UV–Vis spectroscopic studies were also reported.

Transition metal 1,2-bidentate thiolates as building blocks and their construction into cluster complexes

Simple fragments of transition metal 1,2-bidentate thiolates, the so-called building blocks of the general compositions ML3, ML2, ML, M(O)L2, ML2L′, MLL′, etc. have been proposed to constitute the di-, tri- and tetranuclear complexes concerned in this review. Structureal regularities and characteristics have been discussed and summarized according to the thiolato ligands edt and pdt, bdt and tdt, mp, and mpo, and mpp, respectively.

Palladium complexes with simultaneous O:S coordination, syntheses, structures and characterization of complexes with 2-mercaptophenol or 2-mercaptopyridine N-oxide

Abstract Complexes (Et4N)2[Pd2(mp)2(Hmp)2] (1) and [Pd(mpo)2] (2) synthesized from the reactions of palladium chloride with 2-mercaptophenol (H2mp) and 2-mercatopyridine N-oxide (Hmpo) or 2,2′-dithiobis(pyridine N-oxide) (dtpo), respectively, have been characterized by X-ray diffraction analyses and studied by IR, Raman, 1H and 13C NMR, and EI-MS techniques. The palladium atoms in the two compounds are in square planar environments. The average PdO distances are 2.009 A and 2.043 A for 1 and 2, respectively. The results of EHMO calculations show that the PdO bonds are weaker than the PdS bonds in both compounds and large delocalized π bonds extend in the (mp)2Pd2S2 plane in 1 and in the Pd(mpo)2 plane in 2. The reaction of [Ni(mpo)2] with [Pd(COD)Cl2] led to the formation of 2 also, which implies that the bidentate O:S ligand mpo readily transfers from the NiII to the PdII ion.

Trinuclear vanadium dialkyldithiocarbamate complexes. Synthesis, structure and spectroscopic characterization of [Et4N][V3(μ3-S)(η2-μ-S2)3(Et2dtc)3] · 2CH3CN

Abstract A series of [V 3 S 7 (R 2 dtc) 3 ] − complexes (R=Et ( 1 ), HOCH 2 CH 2 ( 2 )) have been studied by X-ray diffraction, IR, NMR and cyclic voltammetry. The V 3 S 7 complexes show almost the same core structure features as those of corresponding [Mo 3 S 7 (R 2 dtc) 3 ] + complexes. Three V atoms possess very similar structure parameters implying their equivalence and electronic delocalization in the V 3 S 7 core. The 1 H NMR signals of the ligating R 2 dtc ligands for the V 3 S 7 complexes occur in pairs. The signals of α-CH 2 for complex 1 were found at 7.64 and 7.66 ppm and at 7.01 and 8.00 ppm for complex 2 , which significantly shifted downfield when compared to those of the respective R 2 dtcNa. This can be explained by the contact effect of the paramagnetic center through the S 2 CNCH 2 group. The cyclic voltammogram displays two reversible couples at −1.14 and 0.00 V responsible for 1−/2− and 0/1− redox processes, respectively, of the V 3 S 7 complexes.

REACTION OF TRANSITION METAL THIOLATO UNITS. V. FORMATION OF A BINUCLEAR MERCURY(II) COMPLEX WITH THE DITHIOLATO LIGAND I-MNT (1,1 -DICYANOETHYLENE-2, 2-DITHIOLATE)

Abstract The binuclear complex (Et 4 N) 4 [Hg 2 ( i -mnt) 4 ] · 2EtOH was obtained from the reaction of Hg(OAc) 2 with K 2 ( i -mnt) in EtOH-MeCN in the presence of Et 4 NBr. The centrosymmetric molecule can be viewed as a dimer of [Hg( i -mnt) 2 ] 2 −. The tetrahedrally coordinated Hg atoms are separated by 3.33 A with two types of coordination modes for the i -mnt ligand : terminal chelation (mode I) and end-to-end bridging (mode II). One of the S—C bonds in the terminal ligand is found to possess a certain degree of double bond character (1.68(1) A), indicating high degree of delocalization. 13 C NMR showed little effect of Hg(II) coordination to the chemical shifts.

A novel network of bis(2-mercapto-3-pyridinol)oxovanadium(IV)_ based on hydrogenbond interactions: synthesis, structure and EPR spectroscopic properties

Abstract Reaction of VCl3 with 2-mercapto-3-pyridinol (H2mpp) in the presence of CH3ONa yields (VO(Hmpp)2 · CH3CN (1). The coordination geometry around the vanadium is square pyramidal, with a VO double bond of 1.602(6) A and average VS and VO distances of 2.392 and 1.943 A, respectively. The mpp ligands behave as the thione tautomer with the N atoms prontonated rather than the thiol alternative form. The intermolecular hydrogen bonding interactions between the protonated N atoms and the terminal O or the coordinated O atoms of mpp ligands result in an infinite two-dimensional network of VO(Hmpp)2. Complex (1) has been characterized by infrared, and EPR spectroscopic studies.

Vanadium chemistry of o-mercaptophenol. Part IV. Construction of heterobinuclear complexes via the synthon [V(mp)3]2− (mp = o-mercaptophenolato dianion). Syntheses and structures of (BzMe3N)2[V(mp)3] · MeCN · 1/2 MeOH and V–Co complexes

The mononuclear complex (BzMe3N)2[V(mp)3] · MeCN · 1/2 MeOH (1) (mp = o-SC6H4O2−) obtained by reacting VCl3 with Na2mp in the presence of BzMe3NBr contains the synthon [V(mp)3]2−. Further reaction with Co2(CO)8 gave [V(mp)3Co(Py)2(MeCN)] · 2MeCN (2) and [V(mp)3Co(DMF)3] (3), depending on the recrystallization conditions. The coordination geometry of the V atoms in all these complexes lies between an octahedron and a trigonal prism. Upon formation of (2) and (3), the terminal oxo atoms of mp become μ2-O bridges between V and Co, while the latter atom is also octahedral.

Structure and characterization of a mononuclear FeII dialkyldithiocarbamate complex Fe(OC4H8dtc)2(DMF)

Abstract A ferrous dialkyldithiocarbamate complex Fe(OC 4 H 8 dtc) 2 (DMF), which contains a Fe atom with distorted square pyramidal geometry and forms a network structure by intermolecular C–H⋯S and C–H⋯O interactions has been obtained and structurally characterized. Proton NMR and IR spectra have been studied. Structural parameters and Mossbauer effect indicate the oxidation state of +2 for the Fe site. A very large quadrupole splitting of 4.10 mm s −1 was observed and associated with an asymmetric 3d 6 (t 4 2g e 2 g ) electronic configuration.

CHIRAL PHOSPHINE LIGANDS DERIVED FROM SUGARS. 8. SYNTHESES OF GOLD(I) COMPLEXES CONTAINING CHIRAL SUGAR PHOSPHINES AND PYRIDINE-1-OXIDE-2-THIOLATE

Abstract Gold(I) compounds [Au(n-MBPA)(2-mpoS)] (2-mpoS=pyridine-1-oxide-2-thiolate; 1, n=2; 2, n=3) with a chiral phosphine derived from glucose (n-MBPA=methyl 4,6-O-benzylidene-n-deoxy-n-(diphenylphosphino)-α-D-altropyranoside, n=2, 3) have been prepared and characterized by 1H, 13C and 31P NMR and molecular vibration spectroscopy. The spectroscopic data suggest a monodentate mode of coordination for 2-mpoS ligand through the S donor.

Integrity and Structural Characteristics of the M6E8 (E=S, Se, Te) Cluster Core: Syntheses and Structures of [Co6S8(PR3)6]n+ (R=Me2Ph, n=1; R=OMe, n=0)

Two new members of the hexanuclear series [Co6S8(PR3)6]n+, complexes [Co6S8(PMe2Ph)6](ClO4) (1) and [Co6S8P(OMe)36] (2), have been synthesizes and characterized by X-ray diffraction analyses. Their formation process was postulated to go through trinuclear μ3--S bridged moieties. The structural characteristics of the M6E8P6 skeleton of a whole series of [M6E8(PR3)6]n+ (M=Co, Cr, Fe, Mo; E=S, Se, Te) complexes are presented in terms of atomic distances and core volumes.