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Dendritic metal chalcogenide (HgS, CdS and PbS) single crystals have been prepared via facile and mild solvothermal process in water or ethanol/water systems. SEM and TEM observations show that HgS and CdS dendrites exhibit whole or part of the two-dimensional (2D) hexagonal snowflake spatial pattern while PbS exhibits whole or part of the three-dimensional (3D) octahedral star-like morphology. Selected area electron diffusion (SAED) and HRTEM show that all of these dendrites are single crystals whose shape evolution is closely related to their intrinsic crystal symmetries. The factors influencing the evolution of the crystal morphology, i.e. reactant molar ratio, solvent, sulfur source, reaction time and temperature have been investigated. Two dimensional six-fold symmetrical HgS and CdS dentrites and 3D four-fold symmetrical PbS dentrite have been fabricated by a facile solvothermal method. The crystal evolution process has been investigated.

Two tripodal ligands, bis(2-benzimidazolylmethyl)(2-pyridylmethyl)amine (L(1)) and bis(2-pyridylmethyl)(2-benzimidazolylmethyl)amine (L(2)), were synthesized. With the third chromophoric ligand antipyrine (Antipy), three series of lanthanide(III) complexes were prepared: [LnL(1)(Antipy)(3)](ClO(4))(3) (series A), [LnL(1)(Antipy)Cl(H(2)O)(2)]Cl(2)(H(2)O)(2) (series B), and [LnL(2)(NO(3))(3)] (series C). The nitrate salt of the free ligand H(2)L(1).(NO(3))(2) and six complexes were structurally characterized: Pr(3+)A, Y(3+)A, Eu(3+)B, Eu(3+)C, Gd(3+)C and Tb(3+)C, in which the two A and three C complexes are isomorphous. Crystallographic studies showed that tripodal ligands L(1) and L(2) exhibited a tripodal coordination mode and formed 1:1 complexes with all lanthanide metal ions. The coordination numbers of the lanthanide metal ions for the A, B, and C complexes were 7, 8, and 10, respectively. Conductivity studies on the B and C complexes in methanol showed that, in the former, the coordinated Cl(-) dissociated to give 3:1 electrolytes and, in the latter, two coordinated NO(3)(-) ions dissociated to give 2:1 electrolytes. Detailed photophysical studies have been performed on the free ligands and their Gd(III), Eu(III), and Tb(III) complexes in several solvents. The results show a wide range in the emission properties of the complexes, which could be rationalized in terms of the coordination situation, the (3)LC level of the complexes, and the subtle variations in the steric properties of the ligands. In particular the Eu(3+)A and Tb(3+)A complexes, in which the central metal ions were wholly coordinated by chromophoric ligands of one L(1) and three antipyrine molecules, had relatively higher emission quantum yields than their corresponding B and C complexes.

The ditopic ligand 1, 2-bis(benzimidazol-1-ylmethyl)benzene (L1) as well as its silver(I) complexes [Ag2L12(CF3CO2)2] (1) and [Ag2L12](CF3SO3)2 · (L1) · 2H2O · 0.5C2H5OH (2) were prepared and structures characterized by X-ray crystallography. The AgI atoms in 1 are trigonally coordinated by two NBIm atoms from the arms of L1 and by one O atom of the anion CF3CO2—, while those in 2 are only linearly ligated by NBIm. Different silver salts of CF3CO2— and CF3SO3— lead to different configurations of the dimeric unit [Ag2L12]2+: chair-form in (1) but boat-form in (2). The discrete molecules in both 1 and 2 are assembled into network structures through face-to-face π · · · π stacking and edge-to-face C—H · · · π interactions in the crystalline state, as well as N—H · · · O and C—H · · · O hydrogen bonds. Solution 1H NMR studies showed the formation of one sole species in solution or a rapid equilibrium was established on the NMR time scale at room temperature. Sessel- und Boot-Konfigurationen von Silber(I)-Komplexen des ditopen Liganden mit Benzimidazolylsubstituenten Der ditope Ligand 1, 2-Bis(benzimidazol-1-ylmethyl)benzen (L1) und seine Silber(I)-Komplexe [Ag2L12(CF3CO2)2] (1) und [Ag2L12](CF3SO3)2 · (L1) · 2H2O · 0.5C2H5OH (2) wurden dargestellt und durch Rontgenstrukturanalysen charakterisiert. Die Silber(I)-Atome in 1 sind trigonal von zwei NBim-Atomen der Arme von L1 und von einem O-Atom des CF3CO2—-Anions koordiniert, wahrend sie in 2 nur linear von NBim koordiniert werden. Die verschiedenen Silbersalze von CF3COO2— bzw. CF3SO3— fuhren zu unterschiedlichen Koonfigurationen der dimeren [Ag2L12]2+-Einheit: Sessel-Form in 1 und Boot-Form in 2. Im kristallinen Zustand sind die isolierten Molekule sowohl von 1 wie von 2 in Netzwerkstrukturen angeordnet mit Flache-zu-Flache-π · · · π-Stapelung und Kante-zu-Flache-C—H · · · π-Wechselwirkung sowie N—H · · · O und C—H · · · O-Wasserstoff-Bruckenbindungen. 1H-NMR-Untersuchungen in Losung zeigen die Bildung von nur einer Spezies oder einer schnellen Gleichgewichtseinstellung in Losung bei Raumtemperatur.

Nanowires of inorganic salts (CaCO 3 , BaCO 3 , CaSO 4 ) were prepared in the nonionic surfactant reverse micelles (Triton X-100/cyclohexane/water) system. The growth process of CaCO 3 nanowire was monitored by the transmission electron microscopy (TEM) technique as a function of time. TEM images reveal that the CaCO 3 nanowires were formed in the reverse micelles by the directional aggregation process. The nanowires of CaCO 3 were 5–30 nm in diameter and had a length more than 10 μm.

The self assembly of AgX with the sulfur-containing multidentate ligand α,α′-bis(8-thioquinoline)-m-xylene (m-XYTQ) affords two isomorphous complexes [Ag(m-XYTQ)]nXn (X=ClO4 1; X=BF4 2). Single crystal X-ray analyses revealed the complexes to contain linear cationic chains of [Ag(m-XYTQ)]nn+ in helical arrangement and the anions are discrete. Intramolecular π⋯π stackings pack the asymmetric units [Ag(m-XYTQ)] in shelves-like arrays while interchain π⋯π interactions between racemic chains constructed the 2D network. The key to helix formation is the folding at the sulfur sites of the spacer xylylene in the ligand. The complexes were also characterized by 1H NMR and IR.

The trans-oxamidato dicopper(II) "synthons", [Cu 2 (trans-L)] 2+ (L= oxen, oxpn, oxap, and oxpy) have been used as construction units when further connected by a second bridging ligand L′ (spacer) to fabricate supramolecular architectures via covalent and hydrogen bonding interactions. The structural topologies of the polymeric networks contained by these compounds depend mainly on the coordination modes of the spacers. When the spacers are 2-connectors bridging two synthons, the resulting compounds usually contain 1-D infinite chains, while 3- or 4-connector provides compounds containing 2-D extended coordination networks. The hydrogen bonds, in which the oxamidate, the spacer, and the water molecules are involved, are prevalent and the predominant intermolecular interactions. Compared with the polymeric networks constructed via covalent bonding interactions between synthons and spacers, the structural topologies of the 3-D supramolecular architectures fabricated via hydrogen bonding interactions are mor...

Copper(II) complexes [Cu(acactn)H2O]2 (1) and [Cu2(acactn)2KClO4]2 (2), where H2acactn is a tetradentate Schiff base bis(acetylacetone)trimethylenediimine, have been prepared and characterized by IR, CV and X-ray single crystal structure analyses. The ligand H2acactn is strongly metallophilic to stabilize Cu(II) ion with a square planar N2O2 coordination environment. Complex 1 can be seen as a hydrogen-bonded dimer of building block Cu(acactn) via bridging water molecules, while complex 2 is a tetrametric adduct of [Cu(acactn)] moiety and KClO4, in which K+ and ClO4− are the bridging-groups. Electrochemical studies displayed that Cu(II)/Cu(I) is an irreversible one-electron reduction process.

A new ligand 4,5-diazafluorene-9-one benzoylhydrazone (HL) and six of its transition metal complexes ML2·nH2O [ M(II) = Mn, n=2, 1; Co, 2, 2; Ni, 2, 3; Cu, 3, 4; Zn, 1.5, 5; Pb, 4, 6] have been prepared and characterized. Elemental analyses, IR, UV–Vis, 1H NMR, molar conductivity and thermal analyses measurements showed that the ligand coordinates to the metal ion with the enolic O and azomethine N atoms of the acylhydrazone group while the 4,5-diazafluorene moiety is free. Single crystal X-ray diffraction studies showed that CoL2(H2O)2, 2, has a centrosymmetric octahedral geometry of N2O4 with the two bidentate ligands in the basal plane and the two water molecules in the axial sites. The molecules of 2 are linked together by intermolecular hydrogen bonds Ndiazafluorene⋯HOH⋯N′diazafluorene and π–π stacking interactions between the diazafluorene rings to form 2D sheets.

Transition metal complexes M(HL)2·nH2O (M(II)=Mn, n=2 (1); Co, n=3 (2); Ni, n=4 (3); Cu, n=3 (4); Zn, n=2 (5); Pb, n=0 (6)) of 4,5-diazafluorene-9-one salicyloylhydrazone (H2L), have been prepared by the reaction of H2L with the metal(II) acetates in EtOH–DMF. X-ray diffraction studies showed that the ligand in the solid state has a pseudo-helical structure in the keto-form. In complexes Mn(HL)2(H2O)2 (1) and Co(HL)2(DMF)2 (2a), the ligand coordinates to the metal ion as a mononegative ion in the enol-form with the enolic oxygen and azomethine nitrogen atoms of the aroylhydrazone group forming a five-membered chelate ring, while the phenolic hydroxyl group and pyridyl-N atoms of the diazafluorene moiety are free. The metal atoms are in octahedral geometry with N2O4 from two ligands HL in the equatorial plane and the axial sites occupied by solvent molecules. The structures were also characterized by IR and 1H NMR spectroscopy.

New nickel(II) and cobalt(II) complexes of a symmetric acyclic mixed O,N,S-donor ligand, S,S′-bis(8-quinolyl)-4-oxo-1,7-dithiaheptane (OESQ), with quinoline as the terminal group, [M(OESQ)(H2O)](NO3)2 [M = NiII (1) and CoII (2)], have been prepared and characterized by elemental analyses, u.v.–vis. and i.r. spectra, and by magnetic susceptibility measurement. Single X-ray diffraction analyses show that (1) and (2) are isomorphous. The nickel (or cobalt) ion in (1) [or (2)] is hexa-coordinated and the complex cation exhibits a slightly distorted-octahedral geometry defined by all five donor atoms of the ON2S2 of OESQ and a water, molecule with N2S2 in equatorial and two oxygens in axial position.

The flexible linear multidentate ligands 1,5-bis(8-quinolylsulfanyl)-3-oxapentane (OESQ) and 1,8-bis(8-quinolylsulfanyl)-3,6-dioxaoctane (ODSQ) reacted with silver(I) perchlorate affording the simple mononuclear complexes [Ag(OESQ)]ClO41 and [Ag(ODSQ)]ClO42, respectively. However, with silver(I) nitrate, novel metallosupramolecular complexes [Ag4(ODSQ)2(η1-NO3)2(η2-NO3)2] 3 and [Ag4(OESQ)(ODSQ)(η1-NO3)2(η2-NO3)2]·H2O 4 were obtained, in which the co-ordination motifs [Ag(OESQ)]+ and [Ag(ODSQ)]+ are spontaneously self-assembled by sulfur-bridged silver(I) ions into tetrametallotricyclic molecules containing the same or mixed building blocks. All four complexes have been characterized by elemental analyses, IR and 1H NMR spectroscopy, and single crystal X-ray diffraction methods. The possible self-assembly process has been discussed with the aid of electrospray mass spectrometry.

The principal g values of a series of [MOXn]m- (M = VIV, CrV, MoV; X = F-, Cl-, Br-; n = 4, 5; m = 1, 2, 3) complexes are calculated by the INDO-CI-Stone method. The results agree well with the experimental data and reveal that the traditional models have some limitations in calculating g values for some complexes of this type.

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.

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.

The reaction of (Bu4N) 4 [Mo8O26] with a suitable amount of 2-mercaptophenol (H2mp) in MeOH in the presence of equimolar Et3N gave the complex (Bu4N) 2 [{MoO2 (2-SC6H4O) }2 (μ-O) ] (2 2′-HOC6H4SSC6H4OH) 2H2O (1) with a one-dimensional chain network formed via hydrogen bondings (average OH OMo distance 2655 A) of the hydroxyl groups in the spacer 2 2′-HOC6H4SSC6H4OH with the terminal oxo groups of the dimolybdenum anions 2 2′-HOC6H4SSC6H4OH was obtained by oxidation of H2mp in the presence of molybdenum when the reaction was run in air The characteristic cis-MoO22 absorptions appear at 913 and 864 cm−1 1 H NMR and 1 H–1 H COSY spectra characterized the phenyl protons of the mercaptophenol groups in the anion and in 22′-HOC6H4SSC6H4OH in the ranges of 6700–6270 and 7368–6799 ppmrespectivelywith 3J and 4J coupling constants of 8 and 1 Hz respectively.

From the reactions of [Et 4 N] 2 MoSe 4 and M(PPh 3 ) n L(M = Cu, Ag, Au: L = Cl, NO 3 : n = 1−2)in univalent comage metal and an MoSe 4 2 unit, [MoSe 4 (CuPPh 3 )PPh 3 ) 2 ] ( 1 ), [MoSe 4 (AgPPh 3 ) Ag(PPh 3 ) 2 ] ( 2 ), [MoSe 4 (Ag-PPh 3 ) 2 ] ( 3 ), [MoSe 4 (AuPPh 3 ) 2 ] ( 4 ), [MoSe 3 )Set(CuPPh 3 ) 3 Cl] ( 6 ), have been isolated and characterized by 93 Mo NMR, IR and Raman spctra. The 93 Mo chemical shifts are mainly dependent upon the shielding effects from the number of the coinage metal atoms around the Mo atom and the geometric structure of the molecule. The shielding order is Au > Cu > Ag. The crystal structure of 4 has been determined by X-ray single-crystal diffraction analysis. It crystallizes in the triclinic space group P -1 with cell constants a = 9.570(2), b = 10.755(2), c = 19.837(4) A : α = 89.59(3), β = 80.37(3), γ = 68.33(3)° and Z = 2 . The molecule has a linear structure with an average Mo distance of 2.846(2) A.

In the study on the reactivity of tetraselenomolybdate, a DMF solution of [Et4N]2[MoSe4] was found to react with 3 equiv of CuCl in the presence of NaS2CNR2 [R2 = Et2, C5H10, (PhCH2)2, Me2] to give a series of Mo−Cu−Se compounds, [Et4N]2[MoCu3Se4(R2NCS2)3] (R2 = Et2 (1a), C5H10 (1b), (PhCH2)2 (1c)) and [Et4N]2[MoCu4Se4(Me2NCS2)4] (2). Furthermore, the reaction of 2 or [Et4N]2[MoSe4(CuCN)2] with [Et4N]2[Cu(SPh)3] in DMF/MeCN afforded a polynuclear Mo−Cu−Se cluster compound, [Et4N]4[MoCu10Se4(PhS)12] (3). [Et4N]2[MoCu3Se4(Et2NCS2)3] (1a) crystallizes in the orthorhombic space group P212121 with cell dimensions a = 12.949(3) A, b = 13.339(3) A, c = 29.744(6) A, V = 5137.6 A3, and Z = 4. Full anisotropic refinements of the structure led to convergence with a value of R = 0.052 (Rw = 0.055) for 453 variables and 6854 reflections (F > 4.0σ(F)). The [MoCu3Se4(Et2NCS2)3]2- anion in 1a comprises three Et2NCS2Cu fragments linked by a slightly distorted tetrahedral MoSe4 moiety. Compound 2 crystallizes in the orthor...

A novel tetranuclear Mo–Cu–Se cluster compound (Ph 4 P) 2 [MoCu 3 OSe 3 Cl 3 (Py)] (Py=pyridine) has been synthesized by the reaction of (Ph 4 P) 2 [MoSe 4 ], CuCl and pyridine in CH 3 CN. X-ray single crystal diffraction analysis reveals that the anion structure consists of an incomplete cubane-like MoCu 3 Se 3 core. The average Mo–Cu and Mo–Se distances are 2.704(7) and 2.394(2) A and the average angles of Se–Mo–Se, Se–Cu–Se, and Se–Cu–Cl are 109.4(2), 104.5(3), and 112.3(3)°, respectively.

The synthetic reactions and spectroscopic studies of molybdenum(tungsten)-copper-sulfur cluster compounds, which can be prepared by the stepwise or unit construction reactions through the successive addition of CuL (L = Cl, Br, R2dtc) across six edges or four faces of MS4 (M = Mo, W) tetrahedra, are described. A series of Mo(W)CuS cluster compounds, (Et4N)2[MoCu2S4(S2CNEt2)2] (1) (Et4N)2- [MoCu2S3O(S2CNC4H8)2 (2), [MoCu2S4(dppe)2] (3) (dppe = bis(diphenylphosphine ethane, (Et4N)2[MoCu3S4(S2CNEt2)3] (4), (Et4N)2[Mo2Cu4S8(S2CNEt2)2] (5), (Et4N)2[Mo2Cu4S6O2(S2CNC4H8)2] (6), [Mo2Cu4S8(dppm)2] (7), [Mo2Cu4S6O2(dppm)2] (8) (dppm = bis(diphenylphosphine)methane), (Et4N)4[MoS4Cu10Br12] (9), (Et4N)4[WS4Cu10Br12] (10), have been prepared and characterized by IR and 95Mo NMR spectra. The polynuclear WCu cluster compound (Et4N)4[WS4Cu10Br12] (10) is characterized by single crystal X-ray diffraction analysis. The anion structure consists of a central WS4 moiety, an octahedral Cu6 and a tetrahedral Cu4 array. The average WCu and WS distances are 2.726(8) and 2.247(7) A and the average angles of SWS, SCuS and SCuBr are 109.5(3), 104.1(4) and 112.6(3)°, respectively.

A novel polynuclear cobalt complex [Co 7 Na 2 (1,2-OSC 6 H 4 ) 8 (DMF) 12 ] was obtained from the reaction of CoBr(PPh 3 ) 3 with Na 2 (1,2-OSC 6 H 4 ) (H 2 mp= o -mercaptophenol) in DMF and its crystal structure has been determined by single crystal X-ray diffraction analysis. The molecular structure contains nine layers. The cobalt and sodium atoms are arranged in nearly linear chain configuration and bridged by 1,2-OSC 6 H 4 2− and DMF ligands via their oxygen atoms.

The reaction of [Ag(dppm)(NO 3 ] 2 with sodium phenylacetate and dppm in THF at room temperature gave rise to the silver complexes [Ag(dppm)(O 2 CCH 2 Ph)] 2 ( 1 ) and [Ag 2 (dppm) 3 ](NO 3 ) 2 ( 2 ), respectively. Their crystal structures have been determined by single crystal X-ray diffraction analysis. Complex 1 is binuclear with a silver-silver separation of 3.080 A and bridged by two dppm ligands. The cation in complex 2 possesses a Ag 2 P 6 core with AgAg distance of 2.987 A and the silver atoms are each coordinated by three phosphorus atoms in an ideal trigonal-planar environment. Their IR, Raman, 1 H and 31 P NMR spectroscopic properties are also reported.

Mononuclear cobalt(II) complexes Co(mbt-N)2(PBu3n)2 (1) (Hmbt = 2-mercaptobenzothiazole; PBu3n = tri-n-butyphosphine) and Co(mbt-S, N)2(dppe)·MeCN (2) [dppe = 1, 2-bis(diphenylphosphino) ethane] were synthesized and characterized by X-ray crystallography, IR and EPR spectra, cyclic voltammetric data and magnetic susceptibility measurements. The Co atom in (1) exhibits an approximate square-planar geometry with the heterocyclic N-donors from mbt bonding to the cobalt atom in a monodentate mode. Complex (2) has a distorted octahedral environment of Co with both the exocyclic-S and the hetero-N donors of mbt bound to the cobalt atom in a bidentate chelating mode. The Co atom in both complexes shows spin state of S =3/2 with μeff of 4.25 and 4.40μB for 1 and 2, respectively.

The reaction of CoCl2, RuCl3, Na2(mp), and PBun3 (H2mp = 2-mercaptophenol, PBun3 = tri-n-butylphosphine) in ethanol in the molar ratio of 0.75:0.25:1:1 gave the complex Co6Ru2(mp)10(PBun3)6. The heterooctanuclear complex consists of six cobalt and two ruthenium ions chelated to as well as bridged by the 2-mercaptophenol ligands in a near-dimeric fashion with two μ2-OR groups bridging the two Co3Ru(mp)5(PBun3)3 fragments without a crystallographic center of symmetry. Each fragment is formed by binding two of the Co(mp)2(PBun3) structural units and one Co(mp) species to a central Ru(III) ion through the S donors of the five mp ligands, while the sixth coordination site of the octahedral Ru environment is completed by a phosphine ligand in the axial position. The Co6Ru2 moiety exhibits a zigzag assembly constructed by the μ2-O and μ2-S bridges of the bidentate 2-mercaptophenol ligands in a highly asymmetric fashion. The Co atoms are square pyramidally coordinated with apices that are occupied by the phosphin...

By the reactions of Pd 2+ , thiolate (PhCH 2 S − or pdt) and dppe or dppp [pdt = SCH 2 CH 2 CH 2 S 2− , dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis(diphenylphosphino)propane] in MeOH, the following complexes, [Pd(SCH 2 Ph) 2 (dppe)] ( 1 ), [Pd(SCH 2 Ph) 2 (dppp)] ( 2 ) and [Pd(pdt)(dppp)] ( 3 ), were prepared. The crystal structure of 2 was analysed by single-crystal X-ray diffraction. The palladium atom is tetra-coordinated with a distorted square-planar geometry of two phosphorus and two sulfur atoms. Their IR, 31 P and 1 H NMR spectra are reported.

The reaction of AgNO 3 , NaS 2 CNEt 2 and H 2 NPhSH in the presence of (Ph 3 P) 3 CuCl in MeOH gave a polynuclear silver cluster compound, [Ag 11 (μ 5 -S)(μ 4 -S 2 CNEt 2 ) 6 (μ 3 -S 2 CNEt 2 ) 3 ]. A cleavage of the S-C bond and release of S 2 from 2-aminothiophenal occurred in the reaction. The core of Ag 11 S consists of five layers: Ag, 3Ag, 3AgS, 3Ag and Ag. The average Ag-Ag and Ag-S c (S c for core sulfur atom) distances are 3.046 and 2.513 , respectively. Copyright © 1996 Elsevier Science Ltd

By the reactions of Pd 2+ , 1,1-dithiolate [SC 6 H 3 (CH 3 )S 2− , SCH 2 CH 2 S 2− or SCH 2 CH (CH 3 )S 2− ] or thiolate (HOC 6 H 4 S − ) and PR 3 (R = Ph, Et) in MeOH, the complexes [Pd(tdt)(PPh 3 ) 2 ] ( 1 ), [Pd 2 (edt) 2 (PPh 3 ) 2 ] ( 2 ), [Pd 2 (pdt) 2 (PPh 3 ) 2 ] ( 3 ), [Pd 2 (edt) 2 (PEt 3 ) 2 ] ( 4 ), [Pd 2 (pdt) 2 (PEt 3 ) 2 ] ( 5 ), [Pd 2 (Hmp) 2 (PPh 3 ) 2 Cl 2 ] ( 6 ) and [Pd 2 (tdt) 2 (PEt 3 ) 2 ] ( 7 ) (tdt = 1,2-toluenedithiolateedt = 1,2-ethanedithiol, pdt = 1,2-propanedithiol and mp = mercaptophenol) were prepared and analysed by X-ray diffraction. All palladium atoms are tetra-coordinated with distorted square-planar geometry of phosphorus and/or sulfur atoms. The reaction mechanism of Pd 2+ , 1,2-dithiolate and PR 3 (R = Et, Ph) is discussed.

A new compound [Na3Co4(μ3-O)2(mpo)8(DMF)4]Br·2DMF (1) was prepared by reacting CoBr(PPh3)3 and Nampo (mpo = 2-mercaptopyridine-N-oxide), and structurally characterized by X-ray diffraction methods. The title compound crystallizes in the triclinic space group P1 with a = 13.393(7), b = 14.00(1), c = 13.029(4) A, α = 92.29(4), β = 110.56(3), γ = 115.32(4)°, V = 2015(2) A3, Z = 1 and R (Rw) = 0.047 (0.053) for 1820 reflections (I > 3 σ(I)). The complex contains four cobalt atoms in the form of a square plane with indirect metal-metal bonds. Each Co atom is coordinated by two bidentate mpo ligands with StOb-D and StOb-T coordination modes, respectively. Two Co2(mpo)4O groups each bridged by μ3-O in the Na3Co4 core are linked by Na3 through the oxygen atoms of the mpo ligands and the bridging μ3-O atoms to form a dumbbell-like structure. The structure of the symmetric tetracobalt cation [Na3Co4(μ3-O)2(mpo)8(DMF)4]+ possesses a crystallographic inversion center through the Na(1) atom. The relevance of the spectroscopic and magnetic properties to the structure of 1 is also discussed.

The tubular form of crystalline boehmite AlOOH was fabricated using AlCl3·6H2O as the alumina precursor in the presence of N-cetyl-N,N,N-trimethylammonium bromide surfactant, and tubular γ-Al2O3 was obtained by calcination of boehmite AlOOH at 520 °C.

Compounds (C)2[Mn2(1,2-pdt)4], where C = Ph4As+ (1a) or Et4N+ (1b), (Et4N)2[Fe2(1,2-pdt)4] (2) and (Ph4P)2[Ni3(1,2-pdt)4]·2MeCN (3), where 1,2-pdt = propane-1,2-dithiolate, were prepared by reaction of disodium 1,2-propanedithiolate with metal chlorides. Compound (1a) crystallizes in the orthorhombic space group Pbca with a = 10.854(2), b = 22.562(4), c = 24.545(6) A, V = 6010.8 A3, Z = 4. The structure was solved from 3003 reflections with I≥3σ(I) and refined to R(Rw) = 0.038(0.045). The two identical fragments [Mn(1,2-pdt)2]− dimerize by bridging through sulfur atoms, on from each of the monomers, to form a rectangular Mn2(μ-S)2 unit. Compound (3) crystallizes in the monoclinic space group P21/c with a = 10.802(2), b = 30.111(7), c = 9.907(3) A, β = 93.60(3)°, V = 3216.0 A3, Z = 2. The structure was refined to R(Rw) = 0.063(0.068) from 2256 reflection with I≥3σ(I). The anion of (3) is formed by chelation of two [Ni(1,2-pdt)2]2− units to a central NiII atom. The three NiS4 planes form a chair with a crystallographic centre of symmetry. Complexes (1) and (2) are paramagnetic and dissociate into monomers in solution while (3) is diamagnetic and may not dissociate. Solid state magnetic susceptibility measurements showed the ground state spins of the MnIII and FeIII ions in (1) and (2) to be S = 2 and S = 3/2, respectively, and the two metal atoms in both molecules exhibit antiferromagnetic interactions. The unsymmetrical 1,2-pdt2− ligand chelates to the metal such that the methyl substituent on the terminal carbon atom is remote from the bridging sulfur.

A sulphur and oxygen alternately bridged polymeric silver (I) complex of S,S'-bis (8-quinolyl)-4-oxa-1,7-dithiaheptane (OETQ), [Ag3(OETQ)(NO3)3]∞, was prepared and its structure was characterized by X-ray crystallography. The 2D brick topological open network of the complex is extended via Ag···O interactions. The NO3− anions interact with Ag atoms in versatile forms to control the crystal packing.

The reaction of Na2Xx (X = S or Se) with CoBr2 and triphenylphosphine in DMF gave rise to the clusters Co6X8(PPh3)6 [X = S (I), X = Se (II)] in high yields. The molecular structures of I and II have been determined by single-crystal X-ray diffraction. Both structures were solved by direct methods and refined by full-matrix least-squares techniques to converge with R = 0.053 for I and 0.048 for II on the basis of 5488 and 8175 reflections with I > 3σ(I), respectively. The two clusters are isostructural with the inner core consisting of a slightly distorted Co6 octahedron. The CoCo distances fall in the ranges of 2.848–2.894 A for I and 2.955–3.037 A for II. Electrochemistry in dichloromethane shows the electron-transfer sequence for I: Co6S8(PPh3)6⇌[Co6S8(PPh3)6]+ and for II: Co6Se8(PPh3)6⇌[CO6Se8(PPh3)6]+⇌[Co6Se8 (PPh3)6]2+.

From reactions of Co(dppm)2Cl2 or Co(dppm)Cl2 with thiolate and elemental selenium or sulphur in DMF, the following complexes were prepared in good yields: [CO2(dppm)(μ-SR)2(SR)2] (R  C6H5, 1; m-C6H4CH3, 2; p-C6H4CH3, 3; and p-C6H4- tC4H9,4). Compound 1 crystallizes in two different isomeric crystals, 1A and 1S, containing three stereoisomers of molecular conformations: 1aa, 1sa and 1ss. The two different crystal structures of compound 1 were confirmed by thermal analysis and IR spectra. Compound 2 crystallizes with molecules of type ss. Compound [Co2(dppe)(μ-SPh)3(SPh)] (5) is an asymmetric molecule with one five-coordinate cobalt atom and one four-coordinate cobalt atom. From the EPR spectra and magnetic susceptibility data, it is deduced that there is antiferromagnetic coupling between the two paramagnetic cobalt(II) atoms in compounds 1–5.

The title compound (Et4N)[Mn(MP-MP)2] (1) was obtained by air oxidation of an acetonitrile solution of MnCl2-4H2O and Na2MP. The structure of 1 was determined by single crystal X-ray diffraction methods. Crystal data: C32H36MnNO4S4, monoclinic, P21/c, a = 9.598(3), b = 16.845(3), c = 10.702(3) A, β = 111.20(1)°, V= 1613.1 A3, Z = 2; Mr = 681.84; d x = 1.40g cm−3 F(000) = 712; μ = 6.8cm−1, crystal dimensions 0.40 × 0.20 × 0.20 mm3. The Mn atom is octahedrally and symmetrically coordinated by two MP-MP2- ligands, each providing two phenolate-oxygen and one disulfide-sulfur atoms to form a terdentate. The presence of an S-S bond is revealed by the distance of 2.093 A, which constitutes the first disulphide chelated to the Mn(III) ion. The paramagnetic nature of the high spin Mn(d4) ion is reflected in a value of μcff of 4.83 μB and broad 1H NMR absorptions at 23 ∼ 25ppm and –12∼-17ppm.

Three new compounds of 2-mercaptophenolate (mp 2- ), trinuclear (Et 4 N)[V 3 (mp) 6 ] or (Ph 4 P)[V 3 (mp) 6 ] (1b), dimeric (Et 4 N) 2 [Co(mp)(Hmp)] 2 (2), and binuclear (Et 4 N) 2 [Ni 2 (Hmp) 2 ] (3), were synthesized and their structures determined. Compound 1b crystallizes in the triclinic space group P1. Compound 2 crystallizes in the monoclinic space group P2 1 /c. Compound 3 crystallizes in the monoclinic space groupe P2 1 /n

The reaction of Co(PPh3)3Cl and K2S2C=C(CN)2 in a 1:1 molar ratio in MeCN led to S-C bond cleavage of [S2C=C(CN)2]2− and allowed isolation of a pentanuclear cobalt cluster compound [Co5(μ3-S)4{μ-SC=C(CN)2}2(PPh3)4] 1 and an octanuclear cobalt cluster compound with mixed Co(I) and Co(II), (PPh4)[Co8(μ4-S)6Br2Cl2(PPh3)4] 2; the core in 1 is a highly distorted Co5 trigonal bipyramid, while that in 2 is a Co8 cube.

A novel polynuclear Mo−Cu cluster compound (Et4N)4[MoS4Cu10Cl12] has been synthesized by the reaction of (NH4)2[MoS4], Et4NCl, and CuCl in acac/DMSO. The reaction mechanism has been monitored by dynamic 95Mo NMR spectra. X-ray single-crystal diffraction analysis reveals that the anion structure consists of a central MoS4 moiety, an octahedral Cu6 array and a tetrahedral Cu4 array, representing the addition of 10 copper atoms across the six edges and four faces of MoS4 tetrahedron. The average Mo−Cu and Mo−S distances are 2.708(8) and 2.238(7) A, respectively.

The low-valence cobalt cluster [Co 7 (μ 4 -S) 3 (μ 3 -S) 3 (PPh 3 ) 6 Br] ( 1 ) was isolated from the reaction of Co(PPh 3 ) 3 Br with Na 2 edt in ethylene chloride. The skeleton [Co 7 S 6 ] + of 1 can be represented as a monocapped-prismane formed by the addition of the capping atom cobalt to the prismane [Co 6 S 6 ] as shown by X-ray single-crystal structure analysis. In this reaction the S 2− ion is derived from the edt 2− ion through cleavage of the CS bond, and incorporated into the building process.

The title compound has been obtained by treating CoCl(PPh3)3 with excess Li2S in chloroform. An X-ray diffraction study established that the structure of the Co7S6 core can be viewed as a monocapped-prismane or a perfect cube [Co8S6] missing a corner cobalt, which possesses a crystallographic C3 axis coincident with the Co(1)P bond.

Reaction of the tripodal ligands tris(N-alkylbenzimidazol-2-ylmethyl)amine with europium perchlorate affords the luminescent complexes [Eu(Rntb)2](ClO4)3·nCH3CN·0.5H2O (R = methyl, npropyl; n = 1, 2) in which the central Eu3+ ion is well encapsulated in a cubic coordination environment. Right- or left-handed screw arrangement of the three arms of the ligand causes the cation [Eu(Rntb)2]3+ to be chiral, and two enantiomers crystallize together in complex [Eu(nPrntb)2](ClO4)3·2CH3CN·0.5H2O to give a racemer, but only one enantiomer is found in complex [Eu(Mentb)2](ClO4)3·CH3CN·0.5H2O.

Dicubane cluster compounds (Et4N)4[Mo2Fe7S8(SR)12] (2A) (R=Ph,a;o-tolyl,b;m-tolyl,c;p-tolyl,d) were made by reaction of (Et4N)2[Fe4(SR)10] (1) with (Et4N)2MoS4 in MeCN at room temperature. The structure,1Hn.m.r.,57Fe Mossbauer spectrum, magnetic susceptibility and cyclic voltammogram are described. (Et4N)3[Mo2Fe6S8Cl6(SR)3] (3) (R=Ph,a;m-tolyl,b) was obtained from the reaction of (2Aa) or (2Ac) with acetyl chloride in MeCN. This is the first time that compound of structural type (2) is transformed into that of structural type (3) by chemical conversion. Compound (2Aa) crystallizes in the triclinic space group P $$\bar 1$$ with Z=1 and unit cell dimensionsa=12.775(4),b=13.076(3), andc=20.576(4) A; the structure was refined to R=7.7% using 4031 unique data with I>3ϖ(Io). Compound (2Ac) 2THF crystallizes in the monoclinic space group P21/n with Z=2 and unit cell dimensionsa=18.022(2),b=18.375(2) andc=22.254(3) A; the structure was refined to R=6.4% using 5173 unique data with I>3ϖ(Io). Compound (3b) crystallizes in the hexagonal space groupP63/m with Z=2 and unit cell dimensionsa=b=16.827(3) andc=15.951(16) A; the structure was refined to R=4.9% using 1296 unique data with I>3ϖ(Io). Its characteristics are discussed and compared with those of known compounds. The ratios of core volumes S4/M4 are within the 2.34–2.40 range for core oxidation level [MoFe3S4]3+ indicating that distortion of the cubane core is a general phenomenon. Different thiolato ligands induce significant changes of structural parameters only at the Fe(SR)6 region for compound (2A) while terminal chlorides induce changes over the whole molecule of (3b) with the latter structure more comparable to [Mo2Fe6S8(SPh)9]5− (3f) with [MoFe3S4]2+ core than to [Mo2Fe6S8(SPh)9]3− (3d). The isotropic shifts of (2A) originate mainly from π-contact interaction. Both1H n.m.r. spectra and magnetic susceptibility measurements indicate practically no magnetic interaction among the three magnetic centres,i.e. a Fe(SR)6 bridge and two [MoFe3S4(SR)3] units. CV studies showed that the reduction of cubane unit having aromatic thiolates is easier than that having aliphatic thiolates as the aliphatic group is electron-donating. In addition, the very similar differences of Ep,c for first and second cubane units in compounds (2A) and in (3d) and (3e) imply that the effect of the first reduced unit [MoFe3S4]2+ upon the second unit [MoFe3S4]3+ is very similar in the two types of dicubane cluster compounds. Synergism in Mo−Fe−S cluster compounds is thus proposed to play an important role in their structural correlation with reactivities and must function in nitrogenase.

The cyclic voltammogram of sodium molybdate in weak acid solution exhibits two main reduction waves, one at −0.8 V (SCE) from the [Mo7O24]6− anion and the other at −1.3 V (SCE) from [MoO4]2−. The former is quasi-reversible and relates to three oxidation waves. The thiomolybdates give only one irreversible reduction wave at about −1.1 V (SCE). The reduction mechanism has also been discussed.

A new dinuclear pentacoordinate ironsulfur compound (Et 4 N) 2 [Fe 2 (1,2-OSC 6 H 4 ] ( 1 was synthesized and the structure of 1·2CH 3 CN was determined to be monoclinic, P 2 1 / n , M r = 950.97, with crystal data a = 11.580(2), b = 16.731(6), c = 12.869(2) A ; β = 98.07(2)°, V = 2468.6 A 3 , Z = 2, D x = 1.279 g cm −3 . From the 2242 independent reflections with I ⩾ 3σ( I o ), the final R converged to 0.069. The centrosymmetric anion of 1 is a dimer of [Fe(mp) 2 ] − bridged by the alkoxy groups of the two bridging mp 2− . The atom Fe(III) is in distorted trigonal bipyramidal environment with O(1) and O(2) as the two apical atoms and O(1′)S(1)S(2) forming the equatorial plane. Both 1 H NMR and CV measurements in DMSO and CH 3 CN showed the existence of species D (CH 3 CN) or M (DMSO), respectively, from the equilibrium (1). The dissociation of 1 into M in strongly polar solvent is further evidenced by 1 H NMR in DMF of intermediate polarity, which gave a ratio of D:M = 8:1. Mossbauer effect measured at 77 K indicated that the ground state spin of Fe(III) in 1 ·2CH 3 CN is .