Synthesis, structural, and magnetic studies on a redox family of tetrametallic vanadium clusters: {VIV4}, {VIII2VIV2}, and {VIII4} butterfly complexes

The synthesis, crystal structures, and magnetic properties are reported for a redox family of butterfly-type tetrametallic vanadium alkoxide clusters, namely [V2(VO)2(acac)4(RC{CH2O}3)2] (R=Me 1, Et 2, CH2OH 3), [V2(VO)2(acac)2(O2CPh)2(MeC{CH2O}3)2] (5), [(VO)4(MeOH)2(O2CPh)2({HOCH2}C{CH2O}3)2] (6), [V4Cl2(dbm)4(RC{CH2OH}3)2] (R=Me 7, Et 8, CH2OH 9), and [V4Cl2(dbm)4(MeO)6] (10). The cluster cores are {VIV4} (6), {VIII2VIV2} (1-5), and {VIII4} (7-10), with examples of both isomeric forms of the of the mixed-valence cores (either VIII or VIV ions forming the butterfly body). Magnetic studies reveal the clusters to be dominated by antiferromagnetic exchange interactions in each case. The magnetic exchange parameters are determined for representative examples of each core type. {VIV4} and {VIII4} have diamagnetic ground states. The two isomeric {VIII2VIV2} types are found to give rise to either an S=0 ground state with a number of low-lying excited states due to competing antiferromagnetic exchange interactions (VIII2 butterfly body) or to a well-isolated S=1 ground state (VIV2 butterfly body).     

One- and two-electron reduced 1,2-diketone ligands in [CrIII(L*)3] (S = 0) and Na2(Et2O)2[VIV(LRed)3] (S = 1/2)

The electronic structures of chromium and vanadium centers coordinated by three reduced 1,2-diketones have been elucidated by using density functional theory (DFT) calculations and a host of physical methods: X-ray crystallography; cyclic voltammetry; ultraviolet-visible (UV-vis), nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR) spectroscopy; and magnetic susceptibility measurements. The metal center in octahedral [CrIII(L*)3]0 (1), a CrIII (d3) ion is coupled antiferromagnetically to three monoanionic ligand pi-radicals affording an S ) 0 ground state. In contrast, Na2(Et2O)2[VIV(LRed)3] (2) (S ) 1/2), possesses a central VIV (d1) ion O,OE-coordinated to three closed-shell, doubly reduced ligands which in turn are coordinated by two Na cations enforcing a trigonal prismatic geometry at the vanadium center. 2 can be oxidized electrochemically by one and two electrons generating a monoanion, [V(L)3]1-, and a neutral species, [V(L)3]0, respectively. DFT calculations atthe B3LYP level show that the one-electron oxidized product contains an octahedral VIV ion coupled antiferromagnetically to one monoanionic ligand pi-radical [VIV(L*)(LRed)2]1- (S ) 0). In contrast, the two-electron oxidized product contains a VIII ion coupled antiferromagnetically to three ligand pi-radicals in an octahedral field[VIII(L*)3]0 (S ) 1/2).     

Regioselective nucleophilic addition of triphenylphosphine to the nitrosylruthenium alkynyl complexes having a hydrotris(pyrazol-1-yl)borate: formation of phosphonio-alkenyl, alkynyl, and allenyl species

A nitrosylruthenium alkynyl complex of TpRuCl(C[triple bond]CPh)(NO)(1a) was reacted with PPh3 in the presence of HBF4.Et2O at room temperature to give a beta-phosphonio-alkenyl complex (E)-[TpRuCl{CH=C(PPh3)Ph}(NO)]BF4(2.BF4). On the other hand, for gamma-hydroxyalkynyl complexes TpRuCl{C[triple bond]CC(R)2OH}(NO)(R = Me (1b), Ph (1c), H (1d)), similar treatments with PPh3 were found to give gamma-phosphonio-alkynyl [TpRuCl{C[triple bond]CC(Me)2PPh3}(NO)]BF4(3.BF4),alpha-phosphonio-allenyl [TpRuCl{C(PPh3)=C=CPh2}(NO)]BF4(4.BF4), and a novel product of gamma-hydroxy-beta-phosphonio-alkenyl (E)-[TpRuCl{CH=C(PPh3)CH2OH}(NO)]BF4(5.BF4), respectively. Dominant factors for the selectivity in affording 3-5 were associated with the steric congestion and electronic properties at the gamma-carbons, along with those around the metal fragment. From the bis(alkynyl) complex TpRu(C[triple bond]CPh)2(NO)6, a bis(beta-phosphonio-alkenyl)(E,E)-[TpRu{CH=C(PPh3)Ph}2(NO)](BF4)2{7.(BF4)2} was produced at room temperature. However, similar reactions at 0 degrees C gave an alkynyl beta-phosphonio-alkenyl complex (E)-[TpRu(C[triple bondCPh){CH=C(PPh3)Ph}(NO)]BF4(8.BF4) as a sole product, of which additional hydration in the presence of HBF4.Et2O afforded a [small beta]-phosphonio-alkenyl ketonyl (E)-[TpRu{CH2C(O)Ph}{CH=C(PPh3)Ph}(NO)]BF(.9BF4). Five complexes, 2-5 and 7 were crystallographically characterized.     

Zinc(II), cadmium(II), mercury(II), and ethylmercury(II) complexes of phosphinothiol ligands

Neutral zinc, cadmium, mercury(II), and ethylmercury(II) complexes of a series of phosphinothiol ligands, PhnP(C6H3(SH-2)(R-3))3-n (n = 1, 2; R = H, SiMe3) have been synthesized and characterized by IR and NMR ((1)H, (13)C, and (31)P) spectroscopy, FAB mass spectrometry, and X-ray structural analysis. The compounds [Zn{PhP(C6H4S-2)2}] (1) and [Cd{Ph2PC6H4S-2}2] (2) have been synthesized by electrochemical oxidation of anodic metal (zinc or cadmium) in an acetonitrile solution of the appropriate ligand. The presence of pyridine in the electrolytic cell affords the mixed complexes [Zn{PhP(C6H4S-2)2}(py)] (3) and [Cd{PhP(C6H4S-2)2}(py)] (4). [Hg{Ph2PC6H4S-2}2] (5) and [Hg{Ph2PC6H3(S-2)(SiMe3-3)}2] (6) were obtained by the addition of the appropriate ligand to a solution of mercury(II) acetate in methanol in the presence of triethylamine. [EtHg{Ph2PC6H4S-2}] (7), [EtHg{Ph2P(O)C6H3(S-2)(SiMe3-3)}] (8), [{EtHg}2{PhP(C6H4S-2)2}] (9), and [{EtHg}2{PhP(C6H3(S-2)(SiMe3-3))2}] (10) were obtained by reaction of ethylmercury(II) chloride with the corresponding ligand in methanol. In addition, in the reactions of EtHgCl with Ph2PC6H4SH-2 and with the potentially tridentate ligand PhP(C6H3(SH-2)(SiMe3-3)) 2, cleavage of the Hg-C bond was observed with the formation of [Hg{Ph2PC6H4S-2}2] (5) and [Hg(EtHg) 2{PhP(O)(C6H3(S-2)(SiMe3-3))2}2] (11), respectively, and the corresponding hydrocarbon. The crystal structures of [Zn3{PhP(C6H4S-2)2}2{PhP(O)(C6H4S-2)2}] (1*), [Cd2{Ph2PC6H4S-2}3{Ph2P(O)C6H4S-2}] (2*), 3, 5, 6, [EtHg{Ph2P(O)C6H4S-2}] (7*), 8, 9, [{EtHg}2{PhP(O)(C6H3(S-2)(SiMe3-3))2}] (10*), and 11 are discussed. The molecular structures of 1, 2, 4, 7, and 10 have also been studied by means of density functional theory (DFT) calculations.     

New heterobimetallic and polymeric selenocarboxylates derived from [M(SeC{O}Ph)4]- (M = Ga and In) as molecular precursors for ternary selenides

(Et3NH)[In(SeC{O}Ph)4].H2O (1) along with heterobimetallic and polymeric metal selenocarboxylates, namely [NaGa(SeC{O}Ph)4] (2), [K(MeCN)2Ga(SeC{O}Ph)4] (3), [NaIn(SeC{O}Ph)4] (4), [K(MeCN)2In(SeC{O}Ph)4] (5), [(Ph3P)2CuIn(SeC{O}Ph)4].CH2Cl2 (6), and [(Ph3P)2AgIn(SeC{O}Ph)4].CH2Cl2 (7), have been synthesized by incorporating either alkali metal ions (Na+ and K+) or group 11 metal ions (Cu(I) and Ag(I)) into the [M(SeC{O}Ph)4]- anion. Crystal structures determined by X-ray crystallography indicate that 3 and 5 have one-dimensional coordination polymeric structures while 6 and 7 have an M(mu-Se)2In (M = Cu, Ag) core. The thermal decomposition of these compounds except 4 lead to the formation of the corresponding metal selenides as confirmed by thermogravimetric analysis and in some cases by powder X-ray diffraction studies.     

Synthesis,structure, and reactions of a three-coordinate nickel-carbene complex, [1,2-Bis(di-tert-butylphosphino)ethane]Ni=CPh(2)

The three-coordinate nickel-carbene complex (dtbpe)Ni=CPh2 (3) was prepared from the thermolysis of the diphenyldiazoalkane complex (dtbpe)Ni(N,N':eta2-N2CPh2) (2) (dtbpe = 1,2-bis(di-tert-butylphosphino)ethane). Complex 3 was structurally characterized by single-crystal X-ray diffraction methods (Ni-C = 1.836(2) A). Complex 3 reacts with 2 equiv of CO2 to afford (dtbpe)Ni{OC(O)CPh2C(O)O} (4), with diphenylketene to give (dtbpe)Ni{OC(=CPh2)CPh2} (5), with excess CO to transfer the carbene fragment and generate diphenylketene and (dtbpe)Ni(CO)2 (6), with sulfur dioxide to give the metallasulfone (dtbpe)Ni{C,S:eta2-S(O)2CPh2} (7), and with the Br?nsted acid [HNMe2Ph][B(C6F5)4] to give the alkyl cation [(dtbpe)Ni(CHPh2)][B(C6F5)4] (8). Complexes 4, 5, and 7 have also been characterized by single-crystal X-ray diffraction methods.     

1,2,3-triazolate-bridged tetradecametallic transition metal clusters [M14(L)6O6(OMe)18X6] (M=FeIII, CrIII and VIII/IV) and related compounds: ground-state spins ranging from S=0 to S=25 and spin-enhanced magnetocaloric effect

We report the synthesis, by solvothermal methods, of the tetradecametallic cluster complexes [M14(L)6O6(OMe)18Cl6] (M=FeIII, CrIII) and [V14(L)6O6(OMe)18Cl6-xOx] (L=anion of 1,2,3-triazole or derivative). Crystal structure data are reported for the {M14} complexes [Fe14(C2H2N3)6O6(OMe)18Cl6], [Cr14(bta)6O6(OMe)18Cl6] (btaH=benzotriazole), [V14O6(Me2bta)6(OMe)18Cl6-xOx] [Me2btaH=5,6-Me2-benzotriazole; eight metal sites are VIII, the remainder are disordered between {VIII-Cl}2+ and {VIV=O}2+] and for the distorted [FeIII14O9(OH)(OMe)8(bta)7(MeOH)5(H2O)Cl8] structure that results from non-solvothermal synthetic methods, highlighting the importance of temperature regime in cluster synthesis. Magnetic studies reveal the {Fe14} complexes to have ground state electronic spins of S相似文献   

New types of hybrid solids of tetravanadate polyanions and cucurbituril

Three inorganic-organic hybrid solids based on tetravanadate polyanions, {V(4)O(12)}(4-) and cucurbituril, Me(10)Q[5] and Q[5], namely (NH(4))(4)[(V(4)O(12))·(Me(10)Q[5]@0.5H(2)O)(2)]·～13H(2)O (1), Li(4)(H(2)O)(5)[(V(4)O(12))·(Me(10)Q[5]@H(2)O)(2)]·～20H(2)O (2), and Na(4)(H(2)O)(2)[(V(4)O(12))·(Q[5])(2)]·～15H(2)O (3), have been synthesized under hydrothermal conditions. In the structure of compound 1, two {Me(10)Q[5]@0.5H(2)O} moieties connect to one {V(4)O(12)}(4-) cluster through an NH(4)(+) counter-cation to form a trimer unit, which further forms a three-dimensional (3D) supramolecular architecture via extensive hydrogen bonds (H-bonds). Compound 2 contains a one-dimensional (1D) covalently bonded chain structure built by alternate {Me(10)Q[5]@H(2)O} moieties and {Li(2)O(4)(H(2)O)(3)}(2+) dimer units. The anionic {V(4)O(12)}(4-) units bond to every another {Li(2)O(4)(H(2)O)(3)}(2+) dimer unit sitting on the chain through multi-uncoordinated water molecules via H-bonds. Compound 3 is built from {V(4)O(12)}(4-) clusters, Q[5], and sodium cations into a two-dimensional (2D) covalent wavy structure, showing interesting connection between the building units, which is packed into 2D through plentiful H-bonds. It has been found that the cations dramatically affect the coordination of the tetravanadate polyanion and cucurbituril.     

Syntheses, structures, and properties of high-nuclear 3d-4f clusters with amino acid as ligand: {Gd6Cu24}, {Tb6Cu26}, and {(Ln6Cu24)2Cu} (Ln = Sm, Gd)

Four novel high-nuclear 3d-4f heterometallic clusters were obtained through the self-assembly of Ln(III), Cu(II), and amino acid ligands (2-methylalanine (mAla), glycine (Gly), and L-proline (Pro), respectively). The metal skeleton of cluster 1, [Gd6Cu24(mu3-OH)30(mAla)16(ClO4)(H2O)22].(ClO4)17.(OH)2.(H2O)2(0), may be described as a huge {Gd6Cu12} octahedron connected with 12 additional Cu(II) ions. The structure of cluster 2, Na4[Tb6Cu26(mu3-OH)30(Gly)18(ClO4)(H2O)22].(ClO4)25.(H2O)42, may be described as a {Tb6Cu24} main structure connected with two [Cu(Gly)(H2O)2]+ groups. Compounds {[Ln6Cu24(mu3-OH)30(Pro)12(Ac)6(ClO4)(H2O)13]2Cu(Pro)2}.(ClO4)18.(OH)16.(H2O)55 (Ln= Sm (3), Gd (4)) are 61-nuclear clusters, which represent the largest known 3d-4f clusters so far, the structure can be described as two {Ln6Cu24} octahedral units connected by a trans-Cu(proline)2 bridge. The electrical conductivity measurements reveal that they are temperature-sensitive semiconductors. The magnetic susceptibility measurements display that compound 4 is ferromagnetic.     

Diverse heteroleptic ytterbium(III) thiocyanate complexes by oxidation from bis(thiocyanato)ytterbium(II)

The new ytterbium(II) thiocyanate complex [Yb(NCS)2(thf)2] (1), synthesised by redox transmetallation between [Hg(SCN)2] and ytterbium metal in THF at room temperature, gave monomeric, eight coordinate [Yb-(NCS)2(dme)3] (2, dme = 1,2-dimethoxyethane) on crystallisation from DME, and is a powerful, synthetically useful reductant. Thus, oxidation of 1 with Hg(SCN)2, Hg(C6F5)2/HOdpp (HOdpp = 2,6-diphenylphenol), TlCp (Cp = C5H5 or CH3C5H4), Tl(Ph2pz) (Ph2pz = 3,5-diphenylpyrazolate) and CCl3CCl3 in THF yielded the ytterbium(II) complexes [Yb(NCS)3(thf)4] (3), [Yb-(NCS)2(Odpp)(thf)3](4), [Yb(NCS)2Cp-(thf)3] (Cp = C5H5 (5), CH3C5H4 (6)), [Yb(NCS)2(Ph2pz)(thf)4] (7) and [Yb(NCS)2Cl(thf)4] (8). In the solid state, complexes 4, 6 and 7 were shown by X-ray crystallography to be six, eight and eight coordinate monomers, respectively. Exclusively terminal, N-bound transoid thiocyanate bonding is observed with eta1-Odpp (4), eta5/-C5H4Me (6) and eta2-Ph2Pz (7) ligands attached approximately perpendicular to the N...N vector. The chloride complex 8 is not a molecular species, but consists of discrete, seven coordinate [YbCl2(thf)5] cations and [Yb(NCS)4(thf)3] anions. By contrast, oxidation of 1 with TlO2CPh gave a mixture of [[Yb(NCS)-(O2CPh)2(thf)2]2] (9) and 3 through rearrangement of an initially formed [Yb(NCS)2(O2CPh)] species. The X-ray structure of 9 indicates a dimeric complex with a (Yb(mu-O2CPh)4Yb] core that contains both bridging bidentate and bridging tridentate benzoate groups, and with a terminal N-bound thiocyanate and two THF ligands on each ytterbium. Reduction of Ph2CO with 1 in THF yielded the dinuclear complex [[Yb(NCS)2(thf)3]2(mu-OC(Ph)2C(Ph)2O)] (10), in which two octahedral Yb centres are bridged by a 1,1,2,2-tetraphenylethane-1,2-diolate ligand, derived from reductive coupling of the benzophenone reagent.     

Silver(I)-ethynide clusters constructed with phosphonate-functionized polyoxovanadates

Two neutral silver(I)-phenylethynide clusters incorporating the [((t)BuPO(3))(4)V(4)O(8)](4-) unit as an integral shell component, namely {(NO(3))(2)@Ag(16)(C≡CPh)(4)[((t)BuPO(3))(4)V(4)O(8)](2)(DMF)(6)(NO(3))(2)}·DMF·H(2)O and {[(O(2))V(2)O(6)](3)@Ag(43)(C≡CPh)(19)[((t)BuPO(3))(4)V(4)O(8)](3)(DMF)(6)}·5DMF·2H(2)O, have been isolated and characterized by X-ray crystallography. The central cavities of the Ag(16) and Ag(43) clusters are occupied by two NO(3)(-) and three [(O(2))V(2)O(6)](4-) template anions, respectively.     

1-D链状簇合物[Ni(enMe)_2]_2[Ni(enMe)_2{HMoo_4~(VI)Mo_4~V_8~(VI)VO_(40)(V~VO_4)}]·4H_2O的水热合成和晶体结构

水热合成了一种新的1-D链状四帽pseudo-Keggin 结构钼钒簇合物[Ni(enMe)2]2- [Ni(enMe)2{H MoVI4MoV4VIV8O40(VVO4)}]4H2O 1,X-射线单晶结构分析表明,该晶体属单斜晶系,C2/c空间群。晶体学参数为a = 26.3006(6), b = 13.6195(3), c = 19.7122(5) ,b = 105.8330(10), V = 6793.0(3) ?, Z = 4, Dc = 2.566 g/cm3, Mr = 2623.96, m = 3.507 mm-1, F(000) =5088, R = 0.0700, wR = 0.1529, S = 1.019。该簇合物是由金属配位桥Ni(enMe)2桥联四帽pseudo-Keggin 结构{HMoVI4MoV4VIV8O40(VVO4)}簇构成一维链状结构,链与链间通过与另外一个配位阳离子[Ni(enMe)2]2+的氢键相互作用构成超分子网状结构。     

Synthesis, structure, and reactivity of ruthenium carboxylato and 2-oxocarboxylato complexes bearing the bis(3,5-dimethylpyrazol-1-yl)acetato ligand

A series of ruthenium(II) acetonitrile, pyridine (py), carbonyl, SO2, and nitrosyl complexes [Ru(bdmpza)(O2CR)(L)(PPh3)] (L = NCMe, py, CO, SO2) and [Ru(bdmpza)(O2CR)(L)(PPh3)]BF4 (L = NO) containing the bis(3,5-dimethylpyrazol-1-yl)acetato (bdmpza) ligand, a N,N,O heteroscorpionate ligand, have been prepared. Starting from ruthenium chlorido, carboxylato, or 2-oxocarboxylato complexes, a variety of acetonitrile complexes [Ru(bdmpza)Cl(NCMe)(PPh3)] (4) and [Ru(bdmpza)(O2CR)(NCMe)(PPh3)] (R = Me (5a), R = Ph (5b)), as well as the pyridine complexes [Ru(bdmpza)Cl(PPh3)(py)] (6) and [Ru(bdmpza)(O2CR)(PPh3)(py)] (R = Me (7a), R = Ph (7b), R = (CO)Me (8a), R = (CO)Et (8b), R = (CO)Ph) (8c)), have been synthesized. Treatment of various carboxylato complexes [Ru(bdmpza)(O2CR)(PPh3)2] (R = Me (2a), Ph (2b)) with CO afforded carbonyl complexes [Ru(bdmpza)(O2CR)(CO)(PPh3)] (9a, 9b). In the same way, the corresponding sulfur dioxide complexes [Ru(bdmpza)(O2CMe)(PPh3)(SO2)] (10a) and [Ru(bdmpza)(O2CPh)(PPh3)(SO2)] (10b) were formed in a reaction of the carboxylato complexes with gaseous SO2. None of the 2-oxocarboxylato complexes [Ru(bdmpza)(O2C(CO)R)(PPh3)2] (R = Me (3a), Et (3b), Ph (3c)) showed any reactivity toward CO or SO2, whereas the nitrosyl complex cations [Ru(bdmpza)(O2CMe)(NO)(PPh3)](+) (11) and [Ru(bdmpza)(O2C(CO)Ph)(NO)(PPh3)](+) (12) were formed in a reaction of the acetato 2a or the benzoylformato complex 3c with an excess of nitric oxide. Similar cationic carboxylato nitrosyl complexes [Ru(bdmpza)(O2CR)(NO)(PPh3)]BF4 (R = Me (13a), R = Ph (13b)) and 2-oxocarboxylato nitrosyl complexes [Ru(bdmpza)(O2C(CO)R)(NO)(PPh3)]BF4 (R = Me (14a), R = Et (14b), R = Ph (14c)) are also accessible via a reaction with NO[BF4]. X-ray crystal structures of the chlorido acetonitrile complex [Ru(bdmpza)Cl(NCMe)(PPh3)] (4), the pyridine complexes [Ru(bdmpza)(O2CMe)(PPh3)(py)] (7a) and [Ru(bdmpza)(O2CC(O)Et)(PPh3)(py)] (8b), the carbonyl complex [Ru(bdmpza)(O2CPh)(CO)(PPh3)] (9b), the sulfur dioxide complex [Ru(bdmpza)(O2CPh)(PPh3)(SO2)] (10b), as well as the nitrosyl complex [Ru(bdmpza)(O2C(CO)Me)(NO)(PPh3)]BF4 (14a), are reported. The molecular structure of the sulfur dioxide complex [Ru(bdmpza)(O2CPh)(PPh3)(SO2)] (10b) revealed a rather unusual intramolecular SO2-O2CPh Lewis acid-base adduct.     

Vanadium(IV) and -(V) complexes with O,N-chelating aminophenolate and pyridylalkoxide ligands

Two different monoanionic O,N-chelating ligand systems, i.e., [OC6H2(CH2NMe2)-2-Me2-4,6]- (1) and [OCMe2([2]-Py)]- (2), have been applied in the synthesis of vanadium(V) complexes. The tertiary amine functionality in 1 caused reduction of the vanadium nucleus to the 4+ oxidation state with either [VOCl3], [V(=NR)Cl3], or [V(=NR)(NEt2)3] (R = Ph, (3a, 5a), R = p-Tol (3b, 5b)), and applying 1 as a reducing agent resulted in the synthesis of the vanadium(IV) complexes [VO(OC6H2(CH2NMe2)-2-Me2-4,6)2] (4) and [V(=NPh)(OC6H2(CH2NMe2)-2-Me2-4,6)2] (6). In the case of [V(=N-p-Tol)(NEt2)(OC6H2(CH2NMe2)-2-Me2-4,6)2] (7b), the reduction was sufficiently slow to allow its characterization by 1H NMR and variable-temperature studies showed it to be a five-coordinate species in solution. Although the reaction of 1 with [V(=N-p-Tol)(O-i-Pr)3] (9b) did not result in reduction of the vanadium nucleus, vanadium(V) compounds could not be isolated. Mixtures of the vanadium(V) (mono)phenolate, [V(=N-p-Tol)(O-i-Pr)2(OC6H2(CH2NMe2)-2-Me2-4,6)] (10), and the vanadium(V) (bis)phenolate, [V(=N-p-Tol)(O-i-Pr)(OC6H2(CH2NMe2)-2-Me2-4,6)2] (11), were obtained. With the pyridylalkoxide 2, no reduction was observed and the vanadium(V) compounds [VOCl2(OCMe2([2]-Py))] (12) and [V(=N-p-Tol)Cl2(OCMe2([2]-Py)] (13) were obtained. 51V NMR showed 7b and 12 to be five-coordinate in solution, whereas for 10, 11, and 13 a coordination number of 6 was found. Compounds 12 and 13 showed decreased activity compared to their nonchelated vanadium(V) analogues when applied as catalysts in ethene polymerization. Two polymorphic forms with a difference in the V-N-C angle of 12.5 degrees have been found for 6. Crystal data: 6.Et2O, triclinic, P1, a = 11.1557(6) A, b = 12.5744(12) A, c = 13.1051(14) A, alpha = 64.244(8) degrees, beta = 70.472(7) degrees, gamma = 87.950(6) degrees, V = 1547(3) A3, Z = 2; 6.C6H6, triclinic, P1, a = 8.6034(3) A, b = 13.3614(4) A, c = 15.1044(5) A, alpha = 98.182(3) degrees, beta = 105.618(2) degrees, gamma = 107.130(2) degrees, V = 1551.00(10) A3, Z = 2; 12, orthorhombic, Pbca, a = 11.8576(12) A, b = 12.6710(13) A, c = 14.722(2) A, V = 2211.9(4) A3, Z = 8.     

Reactions between a sodium amide Na[N(SiMe3)R1] (R1 = SiMe3, SiMe2Ph or But) and a cyanoalkane RCN (R = Ad or Bu(t))

Reactions between sodium amides Na[N(SiMe3)R1] [R1 = SiMe3 (1), SiMe2Ph (2) or But (3)] and cyanoalkanes RCN (R = Ad or But) were investigated. In each case the nitrile adduct [Na{mu-N(SiMe3)2}(NCR)]2 [R = Ad (1a) or But (1b)], trans-[Na{mu-N(SiMe3)(SiMe2Ph)}(NCR)]2 [R = Ad (2a) or But (2b)], [(Na{mu-N(SiMe3)But})3(NCAd)3] (3a) or [(Na{mu-N(SiMe3)But})3(NCBut)n] [n = 3 (3b) or 2 (3c)] was isolated. The reaction of complexes 3a or 3b with benzene afforded the ketimido complex [Na{mu-N=C(Ad)(Ph)}]6.2C6H6 (4a) or [Na{mu-N=C(But)(Ph)}]6 (4b); the former was also prepared in more conventional fashion from NaPh and AdCN. The synthesis and structure of an analogue of complex 1a, [Li{mu-N(SiMe3)2}(NCAd)]2 (5a), is also presented. The compounds 1a, 1b, 2a, 2b, 3, 3b, 4a, 4b and 5a were characterised by X-ray diffraction.     

Toward a magnetostructural correlation for a family of Mn6 SMMs

We have structurally and magnetically characterized a total of 12 complexes based on the Single-Molecule Magnet (SMM) [MnIII6O2(sao)6(O2CH)2(MeOH) 4] (1) (where sao2- is the dianion of salicylaldoxime or 2-hydroxybenzaldeyhyde oxime) that display analogous structural cores but remarkably different magnetic behaviors. Via the use of derivatized oxime ligands and bulky carboxylates we show that it is possible to deliberately increase the value of the spin ground state of the complexes [Mn6O2(Me-sao)6(O2CCPh3)2(EtOH)4] (2), [Mn6O2(Et-sao)6(O2CCMe3)2(EtOH)5] (3), [Mn6O2(Et-sao)6(O2CPh2OPh)2(EtOH)4] (4), [Mn6O2(Et-sao)6(O2CPh4OPh)2(EtOH)4(H2O)2] (5), [Mn6O2(Me-sao)6(O2CPhBr)2(EtOH)6] (6), [Mn6O2(Et-sao)6(O2CPh)2(EtOH)4(H2O)2] (7), [Mn6O2(Et-sao)6{O2CPh(Me)2}2(EtOH)6] (8), [Mn6O2(Et-sao)6(O2C11H15)2(EtOH)6] (9), [Mn6O2(Me-sao)6(O2C-th)2(EtOH)4(H2O)2] (10), [Mn6O2(Et-sao)6(O2CPhMe)2(EtOH)4(H2O)2] (11), and [Mn6O2(Et-sao)6(O2C12H17)2(EtOH)4(H2O)2] (12) (Et-saoH2 = 2-hydroxypropiophenone oxime, Me-saoH2 = 2-hydroxyethanone oxime, HO2CCPh3 = triphenylacetic acid, HO2CCMe3 = pivalic acid, HO2CPh2OPh = 2-phenoxybenzoic acid, HO2CPh4OPh = 4-phenoxybenzoic acid, HO2CPhBr = 4-bromobenzoic acid, HO2CPh(Me)2 = 3,5-dimethylbenzoic acid, HO2C11H15 = adamantane carboxylic acid, HO2C-th = 3-thiophene carboxylic acid, HO2CPhMe = 4-methylbenzoic acid, and HO2C12H17 = adamantane acetic acid) in a stepwise fashion from S = 4 to S = 12 and, in-so-doing, enhance the energy barrier for magnetization reorientation to record levels. The change from antiferromagnetic to ferromagnetic exchange stems from the "twisting" or "puckering" of the (-Mn-N-O-)3 ring, as evidenced by the changes in the Mn-N-O-Mn torsion angles.     

Synthesis and Crystal Structure of a Novel Heptanuclear Ruthenium- and Sodium-containing Polyoxomolybdate [ {Na(H2O)3}2{Ru(dmso)3}2(MoO4)3]·3H2O

The title compound, [{Na(H2O)3}2{Ru(dmso)3}2(MoO4)3]·3H2O, has been obstructure was determined by single-crystal X-ray diffraction method. The crystal crystallizes in the triclinic system, space group P1 with a = 12.3333(3), b = 12.6289(3), c = 32.0284(14)(A), α =79.873(7), β = 87.549(9), y = 64.500(4)°, V = 4429.5(2) (A)3, Z = 4, Mr = 1358.85, Dc = 2.038g/cm3, F(000) = 2696 and μ = 1.874 mm-1. The compound contains a novel pentanuclear triangle bipyramidal core, [{ Ru(dmso)3 } 2(MoO4)3]2-, which consists of two { Ru(dmso)3 } 2+ fragments and three {μ2-MoO4}2- units. Furthermore, the dmso ligands bridge the pentanuclear [Ru2Mo3] core and two [Na(H2O)3]+ fragments together, forming a neutral heptanuclear ruthenium- and sodiumcontaining polyoxomolybdate.     

New metalloligands [M(SC[O]Ph)(4)](-): synthesis and characterization of polymeric [A(MeCN)(x)[M(SC[O]Ph)(4)]] compounds (A = Li,Na and K; M = Ga and In; x = 0-2)

Exploiting the ability of the [M(SC[O]Ph)(4)](-) anion to behave like an anionic metalloligand, we have synthesized [Li[Ga(SC[O]Ph)(4)]] (1), [Li[In(SC[O]Ph)(4)]] (2), [Na[Ga(SC[O]Ph)(4)]] (3), [Na(MeCN)[In(SC[O]Ph)(4)]] (4), [K[Ga(SC[O]Ph)(4)]] (5), and [K(MeCN)(2)[In(SC[O]Ph)(4)]] (6) by reacting MX(3) and PhC[O]S(-)A(+) (M = Ga(III) and In(III); X = Cl(-) and NO(3)(-); and A = Li(I), Na(I), and K(I)) in the molar ratio 1:4. The structures of 2, 4, and 6 determined by X-ray crystallography indicate that they have a one-dimensional coordination polymeric structure, and structural variations may be attributed to the change in the alkali metal ion from Li(I) to Na(I) to K(I). Crystal data for 2 x 0.5MeCN x 0.25H(2)O: monoclinic space group C2/c, a = 24.5766(8) A, b = 13.2758(5) A, c = 19.9983(8) A, beta = 108.426(1) degrees, Z = 8, and V = 6190.4(4) A(3). Crystal data for 4: monoclinic space group P2(1)/c, a = 10.5774(7) A, b = 21.9723(15) A, c = 14.4196(10) A, beta = 110.121(1) degrees, Z = 4, and V = 3146.7(4) A(3). Crystal data for 6: monoclinic space group P2(1)/c, a = 12.307(3) A, b = 13.672(3) A, c = 20.575(4) A, beta = 92.356(4) degrees, Z = 4, and V = 3458.8(12) A(3). The thermal decomposition of these compounds indicated the formation of the corresponding AMS(2) materials.     

Cyanide-bridged linkage isomers with catecholateruthenium(II) centres bound to Mn(I) or M(alkyne) units

Two series of stable cyanide-bridged linkage isomers, namely [(o-O2C6Cl4)(Ph3P)(OC)2Ru(mu-XY)MnL(NO)(eta-C5Me5)] (XY = CN or NC, L = CNBu(t) or CNXyl) and [(o-O2C6Cl4)L(OC)2Ru(mu-XY)M(CO)(PhC-CPh)Tp'] {M = Mo or W, L = PPh3 or P(OPh)3, Tp' = hydrotris(3,5-dimethylpyrazolyl)borate} have been synthesised; pairs of isomers are distinguishable by IR spectroscopy and cyclic voltammetry. The molecular structure of [(o-O2C6Cl4)(Ph3P)(OC)2Ru(mu-NC)Mo(CO)(PhC-CPh)Tp'] has the catecholate-bound ruthenium atom cyanide-bridged to a Mo(CO)(PhC[triple band]CPh)Tp' unit in which the alkyne acts as a four-electron donor; the alignment of the alkyne relative to the Mo-CO vector suggests the fragment (CN)Ru(CO)2(PPh3)(o-O2C6Cl4) acts as a pi-acceptor ligand. The complexes [(o-O2C6Cl4)(Ph3P)(OC)2Ru(mu-XY)Mn(NO)L(eta-C5Me5)] undergo three sequential one-electron oxidation processes with the first and third assigned to oxidation of the ruthenium-bound o-O2C6Cl4 ligand; the second corresponds to oxidation of Mn(I) to Mn(n). The complexes [(o-O2C6Cl4)L(OC)2Ru(mu-XY)M(CO)(PhC[triple band]CPh)Tp'] are also first oxidised at the catecholate ligand; the second oxidation, and one-electron reduction, are based on the M(CO)(PhC[triple band]CPh)Tp' fragment. Chemical oxidation of [(o-O,C6Cl4)(Ph3P)(OC)2Ru(mu-XY)MnL(NO)(eta-C5Me5)] with [Fe(eta-C5H4COMe)(eta-C5H5)][BF4], or of [(o-O2C6Cl4)L(OC)2Ru(mu-XY)M(CO)(PhC[triple band]CPh)Tp'] with AgBF4, gave the paramagnetic monocations [(o-O2C6Cl4)(Ph3P)(OC)2Ru(mu-XY)MnL(NO)(eta-C5Me5)]+ and [(o-O2C6Cl4)L(OC)2Ru(mu-XY)M(CO)(PhC[triple band]CPh)Tp']+, the ESR spectra of which are consistent with ruthenium-bound semiquinone ligands. Linkage isomers are distinguishable by the magnitude of the 31P hyperfine coupling constant; complexes with N-bound Ru(o-O2C6Cl4) units also show small hyperfine coupling to the nitrogen atom of the cyanide bridge.     

Synthesis and properties of Rh(I) and Ir(I) distibine complexes with organometallic co-ligands

The first series of Rh(I) distibine complexes with organometallic co-ligands is described, including the five-coordinate [Rh(cod)(distibine)Cl], the 16-electron planar cations [Rh(cod)(distibine)]BF4 and [Rh{Ph2Sb(CH2)3SbPh2}2]BF4 and the five-coordinate [Rh(CO)(distibine)2][Rh(CO)2Cl2] (distibine=R2Sb(CH2)3SbR2, R=Ph or Me, and o-C6H4(CH2SbMe2)2). The corresponding Ir(I) species [Ir(cod)(distibine)]BF4 and [Ir{Ph2Sb(CH2)3SbPh2}2]BF4 have also been prepared. The complexes have been characterised by 1H and 13C{1H} NMR and IR spectroscopy, electrospray mass spectrometry and microanalysis. The crystal structure of the anion exchanged [Rh(CO){Ph2Sb(CH2)3SbPh2}2]PF(6).3/4CH2Cl2 is also described. The methyl-substituted distibine complexes are less stable than the complexes of Ph2Sb(CH2)3SbPh2, with C-Sb fission occurring in some of the complexes of the former. The salts [Rh(CO){Ph2Sb(CH2)3SbPh2}2]PF6 and [Rh{Ph2Sb(CH2)3SbPh2}2]BF4 undergo oxidative addition with Br2 to give the known [RhBr2{Ph2Sb(CH2)3SbPh2}2]+, while using HCl gives the same hydride complex from both precursors, which is tentatively assigned as [RhHCl2{Ph2Sb(CH2)3SbPh2}]. An unexpected further Rh(III) product from this reaction, trans-[RhCl2{Ph2Sb(CH2)3SbPh2}{PhClSb(CH2)3SbClPh}]Cl, was identified by a crystal structure analysis and represents the first structurally characterised example of a chlorostibine coordinated to a metal. [Rh{Ph2Sb(CH2)3SbPh2}2]BF4 reacts with CO to give [Rh(CO){Ph2Sb(CH2)3SbPh2}2]BF4 initially, and upon further exposure this species undergoes further reversible carbonylation to give a cis-dicarbonyl species thought to be [Rh(CO)2{Ph2Sb(CH2)3SbPh2}{kappa1Sb-Ph2Sb(CH2)3SbPh2}]BF4 which converts back to the monocarbonyl complex when the CO atmosphere is replaced with N2.