Syntheses, structural characterization and properties of transition metal complexes of 5,5'-(1,4-phenylene)bis(1H-tetrazole) (H(2)bdt), 5',5'-(1,1'-biphenyl)-4,4'-diylbis(1H-tetrazole) (H(2)dbdt) and 5,5',5'-(1,3,5-phenylene)tris(1H-tetrazole) (H(3)btt)

The hydrothermal chemistry of a variety of M(II)SO(4) salts with the tetrazole (Ht) ligands 5,5'-(1,4-phenylene)bis(1H-tetrazole) (H(2)bdt), 5',5'-(1,1'-biphenyl)4,4'-diylbis(1H-tetrazole) (H(2)dbdt) and 5,5',5'-(1,3,5-phenylene)tris(1H-tetrazole) (H(3)btt) was investigated. In the case of Co(II), three phases were isolated, two of which incorporated sulfate: [Co(5)F(2)(dbdt)(4)(H(2)O)(6)]·2H(2)O (1·2H(2)O), [Co(4)(OH)(2)(SO(4))(bdt)(2)(H(2)O)(4)] (2) and [Co(3)(OH)(SO(4))(btt)(H(2)O)(4)]·3H(2)O (3·3H(2)O). The structures are three-dimensional and consist of cluster-based secondary building units: the pentanuclear {Co(5)F(2)(tetrazolate)(8)(H(2)O)(6)}, the tetranuclear {Co(4)(OH)(2)(SO(4))(2)(tetrazolate)(6)}(4-), and the trinuclear {Co(3)(μ(3)-OH)(SO(4))(2) (tetrazolate)(3)}(2-) for 1, 2, and 3, respectively. The Ni(II) analogue [Ni(2)(H(0.67)bdt)(3)]·10.5H(2)O (4·10.5H(2)O) is isomorphous with a fourth cobalt phase, the previously reported [Co(2)(H(0.67)bat)(3)]·20H(2)O and exhibits a {M(tetrazolate)(3/2)}(∞) chain as the fundamental building block. The dense three-dimensional structure of [Zn(bdt)] (5) consists of {ZnN(4)}tetrahedra linked through bdt ligands bonding through N1,N3 donors at either tetrazolate terminus. In contrast to the hydrothermal synthesis of 1-5, the Cd(II) material (Me(2)NH(2))(3)[Cd(12)Cl(3)(btt)(8)(DMF)(12)]·xDMF·yMeOH (DMF = dimethylformamide; x = ca. 12, y = ca. 5) was prepared in DMF/methanol. The structure is constructed from the linking of {Cd(4)Cl(tetrazolate)(8)(DMF)(4)}(1-) secondary building units to produce an open-framework material exhibiting 66.5% void volume. The magnetic properties of the Co(II) series are reflective of the structural building units.     

Octahedral Ru(II) amido complexes TpRu(L)(L')(NHR) (Tp = hydridotris(pyrazolyl)borate; L = L' = P(OMe)3 or PMe3 or L = CO and L' = PPh3; R = H,Ph, or tBu): synthesis,characterization, and reactions with weakly acidic C-H bonds

The octahedral Ru(II) amine complexes [TpRu(L)(L')(NH(2)R)][OTf] (L = L' = PMe(3), P(OMe)(3) or L = CO and L' = PPh(3); R = H or (t)Bu) have been synthesized and characterized. Deprotonation of the amine complexes [TpRu(L)(L')(NH(3))][OTf] or [TpRu(PMe(3))(2)(NH(2)(t)Bu)][OTf] yields the Ru(II) amido complexes TpRu(L)(L')(NH(2)) and TpRu(PMe(3))(2)(NH(t)Bu). Reactions of the parent amido complexes or TpRu(PMe(3))(2)(NH(t)Bu) with phenylacetylene at room temperature result in immediate deprotonation to form ruthenium-amine/phenylacetylide ion pairs, and heating a benzene solution of the [TpRu(PMe(3))(2)(NH(2)(t)Bu)][PhC(2)] ion pair results in the formation of the Ru(II) phenylacetylide complex TpRu(PMe(3))(2)(C[triple bond]CPh) in >90% yield. The observation that [TpRu(PMe(3))(2)(NH(2)(t)Bu)][PhC(2)] converts to the Ru(II) acetylide with good yield while heating the ion pairs [TpRu(L)(L')(NH(3))][PhC(2)] yields multiple products is attributed to reluctant dissociation of ammonia compared with the (t)butylamine ligand (i.e., different rates for acetylide/amine exchange). These results are consistent with ligand exchange reactions of Ru(II) amine complexes [TpRu(PMe(3))(2)(NH(2)R)][OTf] (R = H or (t)Bu) with acetonitrile. The previously reported phenyl amido complexes TpRuL(2)(NHPh) [L = PMe(3) or P(OMe)(3)] react with 10 equiv of phenylacetylene at elevated temperature to produce Ru(II) acetylide complexes TpRuL(2)(C[triple bond]CPh) in quantitative yields. Kinetic studies indicate that the reaction of TpRu(PMe(3))(2)(NHPh) with phenylacetylene occurs via a pathway that involves TpRu(PMe(3))(2)(OTf) or [TpRu(PMe(3))(2)(NH(2)Ph)][OTf] as catalyst. Reactions of 1,4-cyclohexadiene with the Ru(II) amido complexes TpRu(L)(L')(NH(2)) (L = L' = PMe(3) or L = CO and L' = PPh(3)) or TpRu(PMe(3))(2)(NH(t)Bu) at elevated temperatures result in the formation of benzene and Ru hydride complexes. TpRu(PMe(3))(2)(H), [Tp(PMe(3))(2)Ru[double bond]C[double bond]C(H)Ph][OTf], [Tp(PMe(3))(2)Ru=C(CH(2)Ph)[N(H)Ph]][OTf], and [TpRu(PMe(3))(3)][OTf] have been independently prepared and characterized. Results from solid-state X-ray diffraction studies of the complexes [TpRu(CO)(PPh(3))(NH(3))][OTf], [TpRu(PMe(3))(2)(NH(3))][OTf], and TpRu(CO)(PPh(3))(C[triple bond]CPh) are reported.     

New coordination polymers with extended arm cyclotriguaiacyclene ligands: 1D chains, and interpenetrating or polycatenating 2D (4(2).6(2))(4.6(2))2 networks

A series of new 1D chain and 2D coordination polymers with cyclotriguaiacylene-type ligands are reported. A zig-zag 1D coordination chain is found in complex [Cd(2)(4ph4py)(NO(3))(3)(H(2)O)(2)(DMA)(2)]·(NO(3))·(DMA)(4), where 4ph4py = tris[4-(4-pyridyl)benzoyl]-cyclotriguaiacylene and DMA = dimethylacetamide, while complex [Zn(4ph4py)(2)(CF(3)COO)(H(2)O)]·(CF(3)COO)(NMP)(7), where NMP = N-methylpyrrolidone, has a doubly bridged coordination chain structure. Complexes [M(3ph3py)(NO(3))(2)]·(NMP)(4) where M = Co or Zn, 3ph3py = tris[3-(3-pyridyl)benzoyl]cyclotriguaiacylene, are isostructural and feature 1D ladder coordination chains. Complexes [Cd(2)(4ph4py)(2)(NO(3))(4)(NMP)]·(NMP)(9)(H(2)O)(4) and [Co(4ph4py)(H(2)O)(2)]·(NO(3))(2)·(DMF)(2), where DMF = dimethylformamide, both have (3,4)-connected 2D coordination polymers with a rare (4(2).6(2))(4.6(2))(2) topology. A 2D coordination polymer with this topology is also found in complex [Co(2)(3ph4py)(2)(NO(3))(H(2)O)(5)]·(NO(3))(3)·(DMF)(9) where 3ph4py = tris[3-(4-pyridyl)benzoyl]cyclotriguaiacylene. All 2D coordination polymer complexes are interpenetrating or polycatenating. [Co(2)(3ph4py)(2)(NO(3))(H(2)O)(5)](3+)polymers form a 2D→3D polycatenation showing self-complementary "hand-shake" interactions between the host-type ligands.     

2-Aminoisobutyric acid in Co(II) and Co(II)/Ln(III) chemistry: homometallic and heterometallic clusters

The synthesis and magnetic properties of 13 new homo- and heterometallic Co(II) complexes containing the artificial amino acid 2-amino-isobutyric acid, aibH, are reported: [Co(II)(4)(aib)(3)(aibH)(3)(NO(3))](NO(3))(4)·2.8CH(3)OH·0.2H(2)O (1·2.8CH(3)OH·0.2H(2)O), {Na(2)[Co(II)(2)(aib)(2)(N(3))(4)(CH(3)OH)(4)]}(n) (2), [Co(II)(6)La(III)(aib)(6)(OH)(3)(NO(3))(2)(H(2)O)(4)(CH(3)CN)(2)]·0.5[La(NO(3))(6)]·0.75(ClO(4))·1.75(NO(3))·3.2CH(3)CN·5.9H(2)O (3·3.2CH(3)CN·5.9H(2)O), [Co(II)(6)Pr(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)CN)(6)]·[Pr(NO(3))(5)]·0.41[Pr(NO(3))(3)(ClO(4))(0.5)(H(2)O)(1.5)]·0.59[Co(NO(3))(3)(H(2)O)]·0.2(ClO(4))·0.25H(2)O (4·0.25H(2)O), [Co(II)(6)Nd(III)(aib)(6)(OH)(3)(NO(3))(2.8)(CH(3)OH)(4.7)(H(2)O)(1.5)]·2.7(ClO(4))·0.5(NO(3))·2.26CH(3)OH·0.24H(2)O (5·2.26CH(3)OH·0.24H(2)O), [Co(II)(6)Sm(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)CN)(6)]·[Sm(NO(3))(5)]·0.44[Sm(NO(3))(3)(ClO(4))(0.5)(H(2)O)(1.5)]·0.56[Co(NO(3))(3)(H(2)O)]·0.22(ClO(4))·0.3H(2)O (6·0.3H(2)O), [Co(II)(6)Eu(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)OH)(4.87)(H(2)O)(1.13)](ClO(4))(2.5)(NO(3))(0.5)·2.43CH(3)OH·0.92H(2)O (7·2.43CH(3)OH·0.92H(2)O), [Co(II)(6)Gd(III)(aib)(6)(OH)(3)(NO(3))(2.9)(CH(3)OH)(4.9)(H(2)O)(1.2)]·2.6(ClO(4))·0.5(NO(3))·2.58CH(3)OH·0.47H(2)O (8·2.58CH(3)OH·0.47H(2)O), [Co(II)(6)Tb(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)CN)(6)]·[Tb(NO(3))(5)]·0.034[Tb(NO(3))(3)(ClO(4))(0.5)(H(2)O)(0.5)]·0.656[Co(NO(3))(3)(H(2)O)]·0.343(ClO(4))·0.3H(2)O (9·0.3H(2)O), [Co(II)(6)Dy(III)(aib)(6)(OH)(3)(NO(3))(2.9)(CH(3)OH)(4.92)(H(2)O)(1.18)](ClO(4))(2.6)(NO(3))(0.5)·2.5CH(3)OH·0.5H(2)O (10·2.5CH(3)OH·0.5H(2)O), [Co(II)(6)Ho(III)(aib)(6)(OH)(3)(NO(3))(3)(CH(3)CN)(6)]·0.27[Ho(NO(3))(3)(ClO(4))(0.35)(H(2)O)(0.15)]·0.656[Co(NO(3))(3)(H(2)O)]·0.171(ClO(4)) (11), [Co(II)(6)Er(III)(aib)(6)(OH)(4)(NO(3))(2)(CH(3)CN)(2.5)(H(2)O)(3.5)](ClO(4))(3)·CH(3)CN·0.75H(2)O (12·CH(3)CN·0.75H(2)O), and [Co(II)(6)Tm(III)(aib)(6)(OH)(3)(NO(3))(3)(H(2)O)(6)]·1.48(ClO(4))·1.52(NO(3))·3H(2)O (13·3H(2)O). Complex 1 describes a distorted tetrahedral metallic cluster, while complex 2 can be considered to be a 2-D coordination polymer. Complexes 3-13 can all be regarded as metallo-cryptand encapsulated lanthanides in which the central lanthanide ion is captivated within a [Co(II)(6)] trigonal prism. dc and ac magnetic susceptibility studies have been carried out in the 2-300 K range for complexes 1, 3, 5, 7, 8, 10, 12, and 13, revealing the possibility of single molecule magnetism behavior for complex 10.     

Syntheses, structures and luminescent properties of zinc(II) and cadmium(II) coordination complexes based on new bis(imidazolyl)ether and different carboxylate ligands

A series of mixed-ligand coordination complexes, namely [Zn(CA)(2)(BIE)] (1), [Zn(OX)(BIE)].H(2)O (2), [Zn(2)(m-BDC)(2)(BIE)(2)] (3), [Cd(m-BDC)(BIE)] (4), [Cd(5-OH-m-BDC)(BIE)] (5), [Zn(5-OH-m-BDC)(BIE)] (6), [Zn(2)(p-BDC)(2)(BIE)(2)].2.5H(2)O (7), [Cd(3)(p-BDC)(3)(BIE)] (8), [Cd(3)(BTC)(2)(BIE)(2)].0.5H(2)O (9) and [Zn(BTCA)(0.5)(BIE)] (10), where CA = cinnamate anion, OX = oxalate anion, m-BDC = 1,3-benzenedicarboxylate anion, 5-OH-m-BDC = 5-OH-1,3-benzenedicarboxylate anion, p-BDC = 1,4-benzenedicarboxylate anion, BTC = 1,3,5-benzenetricarboxylate anion, BTCA = 1,2,3,4-butanetetracarboxylate anion, and BIE = 2,2'-bis(1H-imidazolyl)ether, were synthesized under hydrothermal conditions. In 1, a pair of BIE ligands bridge adjacent Zn(II) atoms to give a centrosymmetric dimer. In 2 and 3, BIE ligands connect Zn(II)-carboxylate chains to form hexagonal honeycomb 6(3)-hcb and square 4(4)-sql layers, respectively. In 4 and 5, m-BDC and 5-OH-m-BDC bridge Cd(II) atoms to give dimeric units, respectively, which are further linked by BIE ligands to form sql nets. In 6, the BIE ligands extend the Zn(II)-carboxylate chains into 2D sinusoidal-like sql nets. The undulated sql nets polycatenate each other in the parallel manner with DOC (degree of catenation) = 2, yielding a rare 2D --> 3D parallel polycatenation net. In 7, the BIE and p-BDC ligands link the Zn(ii) atoms to give a rare 3-fold interpenetrated 3-connected 10(3)-ths net. 8 contains unusual edge-sharing polyhedral rods formed by [Cd(3)(CO(2))(6)] clusters. Each rod is connected by the benzene rings of p-BDC in four directions into a simple alpha-Po topology. In 9, two kinds of different 2D Cd-BTC layers are alternately linked to each other by sharing Cd(ii) centers to form a 3D framework, which is further linked by two kinds of BIE ligand to produce a complicated 3D polymeric structure. 10 possesses a unique (3,4)-connected 3D framework with (8(3))(2)(8(5).10) topology. The structural differences described indicate the importance of carboxylate ligands and metals in the framework formation of coordination complexes. The infrared spectra, thermogravimetric and luminescent properties were also investigated in detail for the compounds.     

Reactions of cadmium(II) nitrate with 4-(trimethylammonio)benzenethiolate in the presence of N-donor ligands

Reactions of Cd(NO(3))(2)·4H(2)O with TabHPF(6) (TabH = 4-(trimethylammonio)benzenethiol) and Et(3)N in the presence of NH(4)SCN and five other N-donor ligands such as 2,2'-bipyridine (2,2'-bipy), phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (2,9-dmphen), 2,6-bis(pyrazd-3-yl)pyridine (bppy) and 2,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)pyridine (bdmppy) gave rise to a family of Cd(II)/thiolate complexes of N-donor ligands, {[Cd(2)(μ-Tab)(4)(NCS)(2)](NO(3))(2)·MeOH}(n) (1), [Cd(2)(μ-Tab)(2)(L)(4)](PF(6))(4) (2: L = 2,2'-bipy; 3: L = phen), [Cd(Tab)(2)(L)](PF(6))(2) (4: L = 2,9-dmphen; 5: L = bppy), and [Cd(2)(μ-Tab)(2)(Tab)(2)(bdmppy)](2)(PF(6))(8)·H(2)O (6·H(2)O). These compounds were characterized by elemental analysis, IR spectra, UV-Vis spectra, (1)H NMR, electrospray ionization (ESI) mass spectra and single-crystal X-ray diffraction. For 1, each [Cd(NCS)](+) fragment is connected to its equivalents via a pair of Tab bridges to a one-dimensional chain. For 2 and 3, two [Cd(2,2'-bipy)(2)](2+) or [Cd(phen)(2)](2+) units are linked by a pair of Tab bridges to form a cationic dimeric structure. The Cd atom in [Cd(Tab)(2)(L)](2+) dication of 4 or 5 is coordinated by two Tab ligands and chelated by two N atoms from 2,9-dmphen (4) or three N atoms from bppy (5), forming a distorted tetrahedral (4) or trigonal bipyramidal (5) coordination geometry. For 6, each of two [Cd(Tab)(bdmppy)] fragments is linked to one [(Tab)Cd(μ-Tab)(2)Cd(Tab)] fragment via two Tab bridges to generate a unique cationic zigzag tetrameric structure where the Cd centers take a tetrahedral or a trigonal bipyramidal coordination geometry. The results may provide an interesting insight into mimicking the coordination spheres of the Cd(II) sites of metallothioneins and their interactions with various N-donor ligands encountered in nature.     

7-Methylguanine: protonation, formation of linkage isomers with trans-(NH3)2Pt(II), and base pairing properties

Three protonated forms of 7-methylguanine (7-MeGH, 1) with different counter ions, [7-MeGH(2)]X (X = NO(3), 1a; ClO(4), 1b; BF(4), 1c) and two Pt(II) complexes, trans-[Pt(NH(3))(2)(7-MeGH-N9)(2)](ClO(4))(2) (4) and trans-[Pt(NH(3))(2)(7-MeGH-N9)(7-MeGH-N3)](ClO(4))(2)·3H(2)O (5) are described and their X-ray crystal structures are reported. 1a-1c form infinite ribbons via pairs of intermolecular hydrogen bonds between N1H···O6 and N3···N2H(2) sites, with anions connecting individual ribbons, thereby generating extended sheets. 4 and 5 do not display unusual features, except that 5 represents a rare case of a bis(nucleobase) complex of Pt(II) in which linkage isomers occur. Unlike in a previously reported compound, [Pt(dien)(7-MeGH-N9)](NO(3))(ClO(4)), the Pt coordination planes and the 7-MeGH planes are not coplanar in 4 and 5. The hydrogen bonding behaviour of 7-MeGH, free and when platinated at N9 (complex 4), was studied in Me(2)SO-d(6). It revealed the following: (i) there is no detectable self-association of 1 in Me(2)SO solution. (ii) 1 and 1-methylcytosine (1-MeC) form Watson-Crick pairs. (iii) 4 does not self-associate. (iv) 4 associates with 1-MeC in the Watson-Crick fashion. (v) 4 and 1 interact in solution, but no model can be proposed at present. (vi) Remarkable interaction shifts between 4 and 1 occur when NH(3) is liberated from trans-(NH(3))(2)Pt(II) to give NH(4)(+) in Me(2)SO-d(6). Feasible models, which imply the presence of deprotonated 7-MeG(-) species are proposed. Finally, DFT calculations were carried out to qualitatively estimate the effect of 7-MeGH acidity in [Pt(dien)(7-MeGH-N9)](2+) in dependence of the dihedral angle between the Pt coordination plane and the nucleobase.     

1,1-ethylenedithiolato complexes of palladium(II) and platinum(II) with isocyanide and carbene ligands

The reactions of [Tl(2)[S(2)C=C[C(O)Me](2)]](n) with [MCl(2)(NCPh)(2)] and CNR (1:1:2) give complexes [M[eta(2)-S(2)C=C[C(O)Me](2)](CNR)(2)] [R = (t)Bu, M = Pd (1a), Pt (1b); R = C(6)H(3)Me(2)-2,6 (Xy), M = Pd (2a), Pt (2b)]. Compound 1b reacts with AgClO(4) (1:1) to give [[Pt(CN(t)Bu)(2)](2)Ag(2)[mu(2),eta(2)-(S,S')-[S(2)C=C[C(O)Me](2)](2)]](ClO(4))(2) (3). The reactions of 1 or 2 with diethylamine give mixed isocyanide carbene complexes [M[eta(2)-S(2)C=C[C(O)Me](2)](CNR)[C(NEt(2))(NHR)]] [R = (t)Bu, M = Pd (4a), Pt (4b); R = Xy, M = Pd (5a), Pt (5b)] regardless of the molar ratio of the reagents. The same complexes react with an excess of ammonia to give [M[eta(2)-(S,S')-S(2)C=C[C(O)Me](2)](CN(t)Bu)[C(NH(2))(NH(t)Bu)]] [M = Pd (6a), Pt (6b)] or [M[eta(2)-(S,S')-S(2)C=C[C(O)Me](2)][C(NH(2))(NHXy)](2)] [M = Pd (7a), Pt (7b)] probably depending on steric factors. The crystal structures of 2b, 4a, and 4b have been determined. Compounds 4a and 4b are isostructural. They all display distorted square planar metal environments and chelating planar E,Z-2,2-diacetyl-1,1-ethylenedithiolato ligands that coordinate through the sulfur atoms.     

Nine Diiron(II) Complexes of Three Bis-tetradentate Pyrimidine Based Ligands with NCE (E = S, Se, BH(3)) Coligands

Three bis-tetradentate acyclic amine ligands differing only in the arm length of the pyridine pendant arms attached to the 4,6-positions of the pyrimidine ring, namely, 4,6-bis[N,N-bis(2'-pyridylethyl)aminomethyl]-2-phenylpyrimidine (L(Et)), 4,6-bis[N,N-bis(2'-pyridylmethyl)aminomethyl]-2-phenylpyrimidine (L(Me)), and 4,6-[(2'-pyridylmethyl)-2'-pyridylethyl)aminomethyl]-2-phenylpyrimidine (L(Mix)) have been used to synthesize nine air-sensitive diiron(II) complexes: [Fe(II)(2)L(Et)(NCS)(4)]·MeOH·(3)/(4)H(2)O (1·MeOH·(3)/(4)H(2)O), [Fe(II)(2)L(Et)(NCSe)(4)]·H(2)O (2·H(2)O), [Fe(II)(2)L(Et)(NCBH(3))(4)]·(5)/(2)H(2)O (3·(5)/(2)H(2)O), [Fe(II)(2)L(Me)(NCS)(4)]·(1)/(2)H(2)O (4·(1)/(2)H(2)O), [Fe(II)(2)L(Me)(NCSe)(4)] (5), [Fe(II)(2)L(Me)(NCBH(3))(4)]·(3)/(2)H(2)O (6·(3)/(2)H(2)O), [Fe(II)(2)L(Mix)(NCS)(4)]·(1)/(2)H(2)O (7·(1)/(2)H(2)O), [Fe(II)(2)L(Mix)(NCSe)(4)]·(3)/(2)H(2)O (8·(3)/(2)H(2)O), and [Fe(II)(2)L(Mix)(NCBH(3))(4)]·(3)/(2)H(2)O (9·(3)/(2)H(2)O). Complexes 3·(5)/(2)H(2)O, 4·(1)/(2)H(2)O, 5, 6·(3)/(2)H(2)O, and 8·(3)/(2)H(2)O were structurally characterized by X-ray crystallography, revealing, in all cases, both of the iron(II) centers in an octahedral environment with two NCE (E = S, Se, or BH(3)) anions in a cis-position relative to one another. Variable temperature magnetic susceptibility measurements showed that all nine diiron(II) complexes are stabilized in the [HS-HS] state from 300 K to 4 K, and exhibit weak antiferromagnetic coupling. M?ssbauer spectroscopy confirmed the spin and oxidation states of eight of the nine complexes (the synthesis of air-sensitive complex 3 was not readily reproduced).     

Magnetic nanosized {M(II)24}-wheel-based (M = Co, Ni) coordination polymers

Two 3D coordination polymers, [Co(24)(OH)(12)(SO(4))(12)(ip)(6)(DMSO)(18)(H(2)O)(6)]·(DMSO)(6)(EtOH)(6)(H(2)O)(36) (1·guests, ip = isophthalate) and [Ni(24)(OH)(12)(SO(4))(12)(ip)(6)(DMSO)(12)(H(2)O)(12)]·(DMSO)(6)(EtOH)(6)(H(2)O)(20) (2·guests), constructed with nanosized tetraicosanuclear Co(II) and Ni(II) wheels are solvothermally synthesized. Both complexes show intra- and interwheel dominant antiferromagnetic interactions.     

Two novel heterometallic Cu(II)-Sr(II) coordination polymers based on 3,5-pyrazoledicarboxylic acid: synthesis, crystal structures and magnetic properties

The syntheses, crystal structures and magnetic properties are described for two novel 2D heterometallic Cu(II)-Sr(II) coordination polymers {Sr(H(2)O)(6)[(Im)(4)Cu(4)(pdc)(4)Sr(H(2)O)(4)]·6H(2)O}(n) (1) and [Cu(2)(H(2)O)(2)(pdc)(2)Sr(H(2)O)(3)](n) (2) (H(3)pdc = 3,5-pyrazoledicarboxylic acid; Im = imidazole). The 1 : 1 : 1 : 5 reaction of SrCl(2)·6H(2)O, Cu(NO(3))(2)·3H(2)O, H(3)pdc and imidazole in H(2)O-EtOH at 120 °C under autogenous pressure gave 1. Complex 2 was obtained from the 1 : 1 : 1 H(3)pdc/Sr(OH)(2)·8H(2)O/Cu(NO(3))(2)·3H(2)O reaction mixture in H(2)O-EtOH under solvothermal conditions. Complex 1 can be described as a 2D grid-shaped network with the four Cu(II) ions in a saddle-like conformation. In complex 2, Sr(II) ions link metalloligands [Cu(2)(pdc)(2)(H(2)O)(2)](2-) to generate a 2D layer framework. Variable-temperature solid-state dc magnetic susceptibility studies have been performed in the temperature range 2.0-300 K for complexes 1 and 2. Antiferromagnetic Cu(II)···Cu(II) exchange interactions were found for both 1 and 2.     

Nitrate-Bridged "Pseudo-Double-Propeller"-Type Lanthanide(III)-Copper(II) Heterometallic Clusters: Syntheses, Structures, and Magnetic Properties

Two discrete nitrate-bridged novel "pseudo-double-propeller"-shaped hexanuclear Cu/Ln clusters of the formula [Cu(4)Ln(2)L(4)L'(4)(NO(3))(2)(OH(2))(2)]·3NO(3)·4H(2)O [Ln = Dy, Gd; LH = o-vanilin; L'H = 2-(hydroxyethyl)pyridine] were synthesized and characterized. Single-crystal X-ray diffraction studies revealed the trimeric half-propeller-type Cu(2)/Ln core connected to other opposite-handed similar trimers by a bridging nitrate ligand. The Dy analogue, [Cu(4)Dy(2)L(4)L'(4)(NO(3))(2)(OH(2))(2)]·3NO(3)·4H(2)O, shows frequency-dependent out-of-phase alternating-current magnetic susceptibility, which indicates that this novel discrete [Cu(4)Dy(2)] heterometallic cluster may exhibit single-molecule-magnet behavior.     

Enhancing gas adsorption and separation capacity through ligand functionalization of microporous metal-organic framework structures

Hydroxyl- and amino- functionalized [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O leads to two new structures, [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O (BDC=terephthalic acid, TED=triethylenediamine, BDC-OH=2-hydroxylterephthalic acid, BDC-NH(2)=2-aminoterephthalic acid). Single-crystal X-ray diffraction and powder X-ray diffraction studies confirmed that the structures of both functionalized compounds are very similar to that of their parent structure. Compound [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O can be considered a 3D porous structure with three interlacing 1D channels, whereas both [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O contain only 1D open channels as a result of functionalization of the BDC ligand by the OH and NH(2) groups. A notable decrease in surface area and pore size is thus observed in both compounds. Consequently, [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O takes up the highest amount of H(2) at low temperatures. Interestingly, however, both [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O show significant enhancement in CO(2) uptake at room temperature, suggesting that the strong interactions between CO(2) and the functionalized ligands, indicating that surface chemistry, rather than porosity, plays a more important role in CO(2) adsorption. A comparison of single-component CO(2), CH(4), CO, N(2), and O(2) adsorption isotherms demonstrates that the adsorption selectivity of CO(2) over other small gases is considerably enhanced through functionalization of the frameworks. Infrared absorption spectroscopic measurements and theoretical calculations are also carried out to assess the effect of functional groups on CO(2) and H(2) adsorption potentials.     

Coordination-position isomeric M(II)Cu(II) and Cu(II)M(II) (M = Co, Ni, Zn) complexes derived from macrocyclic compartmental ligands

The dinucleating macrocyclic ligands (L(2;2))(2-) and (L(2;3))(2-), comprised of two 2-[(N-methylamino)methyl]-6-(iminomethyl)-4-bromophenolate entities combined by the -(CH(2))(2)- chain between the two aminic nitrogen atoms and by the -(CH(2))(2)- or -(CH(2))(3)- chain between the two iminic nitrogen atoms, have afforded the following M(II)Cu(II) complexes: [CoCu(L(2;2))](ClO(4))(2).MeCN (1A), [NiCu(L(2;2))](ClO(4))(2) (2A), [ZnCu(L(2;2))](ClO(4))(2).0.5MeCN.EtOH (3A), [CoCu(L(2;3))(MeCN)(2-PrOH)](ClO(4))(2) (4A), [NiCu(L(2;3))](ClO(4))(2) (5A), and [ZnCu(L(2;3))](ClO(4))(2).1.5DMF (6A). [CoCu(L(2;2))(MeCN)(3)](ClO(4))(2) (1A') crystallizes in the monoclinic space group P2(1)/n, a = 11.691(2) A, b = 18.572(3) A, c = 17.058(3) A, beta= 91.18(2) degrees, V = 3703(1) A(3), and Z = 4. [NiCu(L(2;2))(DMF)(2)](ClO(4))(2) (2A') crystallizes in the triclinic space group P(-)1, a = 11.260(2) A, b = 16.359(6) A, c = 10.853(4) A, alpha= 96.98(3) degrees, beta= 91.18(2) degrees, gamma= 75.20(2) degrees, V = 1917(1) A(3), and Z = 2. 4A crystallizes in the monoclinic space group P2(1)/c, a = 15.064(8) A, b = 11.434(5) A, c = 21.352(5) A, beta= 95.83(2)degrees, V = 3659(2) A(3), and Z = 4. The X-ray crystallographic results demonstrate the M(II) to reside in the N(amine)(2)O(2) site and the Cu(II) in the N(imine)(2)O(2) site. The complexes 1-6 are regarded to be isomeric with [CuCo(L(2;2)))](ClO(4))(2).DMF (1B), [CuNi(L(2;2)))](ClO(4))(2).DMF.MeOH (2B), [CuZn(L(2;2)))](ClO(4))(2).H(2)O (3B)), [CuCo(L(2;3)))](ClO(4))(2).2H(2)O (4B), [CuNi(L(2;3)))](ClO(4))(2) (5B), and [CuZn(L(2;3)))](ClO(4))(2).H(2)O (6B) reported previously, when we ignore exogenous donating and solvating molecules. The isomeric M(II)Cu(II) and Cu(II)M(II) complexes are differentiated by X-ray structural, magnetic, visible spectroscopic, and electrochemical studies. The two isomeric forms are significantly stabilized by the "macrocyclic effect" of the ligands, but 1A is converted into 1B on an electrode, and 2A is converted into 2B at elevated temperature.     

Artificial amino acids in nickel(II) and nickel(II)/lanthanide(III) chemistry

The synthesis and magnetic properties of five new homo- and heterometallic nickel(II) complexes containing artificial amino acids are reported: [Ni(4)(aib)(3)(aibH)(3)(NO(3))](NO(3))(4)·3.05MeOH (1·3.05MeOH), [Ni(6)La(aib)(12)](NO(3))(3)·5.5H(2)O (2·5.5H(2)O), [Ni(6)Pr(aib)(12)](NO(3))(3)·5.5H(2)O (3·5.5H(2)O), [Ni(5)(OH)(2)(l-aba)(4)(OAc)(4)]·0.4EtOH·0.3H(2)O 6(4·0.4EtOH·0.3H(2)O), and [Ni(6)La(l-aba)(12)][La(2)(NO(3))(9)] (5; aibH = 2-aminoisobutyric acid; l-abaH = l-2-aminobutyric acid). Complexes 1 and 4 describe trigonal-pyramidal and square-based pyramidal metallic clusters, respectively, while complexes 2, 3, and 5 can be considered to be metallocryptand-encapsulated lanthanides. Complexes 4 and 5 are chiral and crystallize in the space groups I222 and P2(1)3, respectively. Direct-current magnetic susceptibility studies in the 2-300 K range for all complexes reveal the presence of dominant antiferromagnetic exchange interactions, leading to small or diamagnetic ground states.     

A family of 13 tetranuclear zinc(II)-lanthanide(III) complexes of a [3+3] Schiff-base macrocycle derived from 1,4-diformyl-2,3-dihydroxybenzene

A family of thirteen tetranuclear heterometallic zinc(II)-lanthanide(III) complexes of the hexa-imine macrocycle (L(Pr))(6-), with general formula Zn(II)(3)Ln(III)(L(Pr))(NO(3))(3)·xsolvents (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm or Yb), were prepared in a one-pot synthesis using a 3:1:3:3 reaction of zinc(II) acetate, the appropriate lanthanide(III) nitrate, the dialdehyde 1,4-diformyl-2,3-dihydroxybenzene (H(2)L(1)) and 1,3-diaminopropane. A hexanuclear homometallic zinc(II) macrocyclic complex [Zn(6)(L(Pr))(OAc)(5)(OH)(H(2)O)]·3H(2)O was obtained using a 2:0:1:1 ratio of the same reagents. A control experiment using a 1:0:1:1 ratio failed to generate the lanthanide-free [Zn(3)(L(Pr))] macrocyclic complex. The reaction of H(2)L(1) and zinc(II) acetate in a 1:1 ratio yielded the pentanuclear homometallic complex of the dialdehyde H(2)L(1), [Zn(5)(L(1))(5)(H(2)O)(6)]·3H(2)O. An X-ray crystal structure determination revealed [Zn(3)(II)Pr(III)(L(Pr))(NO(3))(2)(DMF)(3)](NO(3))·0.9DMF has the large ten-coordinate lanthanide(III) ion bound in the central O(6) site with two bidentate nitrate anions completing the O(10) coordination sphere. The three square pyramidal zinc(II) ions are in the outer N(2)O(2) sites with a fifth donor from DMF. Measurement of the magnetic properties of [Zn(II)(3)Dy(III)(L(Pr))(NO(3))(3)(MeOH)(3)]·4H(2)O with a weak external dc field showed that it has a frequency-dependent out-of-phase component of ac susceptibility, indicative of slow relaxation of the magnetization (SMM behaviour). Likewise, the Er and Yb analogues are field-induced SMMs; the latter is only the second example of a Yb-based SMM. The neodymium, ytterbium and erbium complexes are luminescent in the solid phase, but only the ytterbium and neodymium complexes show strong lanthanide-centred luminescence in DMF solution.     

Dithiocarboxylate complexes of ruthenium(II) and osmium(II)

The ruthenium(II) complexes [Ru(R)(κ(2)-S(2)C·IPr)(CO)(PPh(3))(2)](+) (R = CH=CHBu(t), CH=CHC(6)H(4)Me-4, C(C≡CPh)=CHPh) are formed on reaction of IPr·CS(2) with [Ru(R)Cl(CO)(BTD)(PPh(3))(2)] (BTD = 2,1,3-benzothiadiazole) or [Ru(C(C≡CPh)=CHPh)Cl(CO)(PPh(3))(2)] in the presence of ammonium hexafluorophosphate. Similarly, the complexes [Ru(CH=CHC(6)H(4)Me-4)(κ(2)-S(2)C·ICy)(CO)(PPh(3))(2)](+) and [Ru(C(C≡CPh)=CHPh)(κ(2)-S(2)C·ICy)(CO)(PPh(3))(2)](+) are formed in the same manner when ICy·CS(2) is employed. The ligand IMes·CS(2) reacts with [Ru(R)Cl(CO)(BTD)(PPh(3))(2)] to form the compounds [Ru(R)(κ(2)-S(2)C·IMes)(CO)(PPh(3))(2)](+) (R = CH=CHBu(t), CH=CHC(6)H(4)Me-4, C(C≡CPh)=CHPh). Two osmium analogues, [Os(CH=CHC(6)H(4)Me-4)(κ(2)-S(2)C·IMes)(CO)(PPh(3))(2)](+) and [Os(C(C≡CPh)=CHPh)(κ(2)-S(2)C·IMes)(CO)(PPh(3))(2)](+) were also prepared. When the more bulky diisopropylphenyl derivative IDip·CS(2) is used, an unusual product, [Ru(κ(2)-SC(H)S(CH=CHC(6)H(4)Me-4)·IDip)Cl(CO)(PPh(3))(2)](+), with a migrated vinyl group, is obtained. Over extended reaction times, [Ru(CH=CHC(6)H(4)Me-4)Cl(BTD)(CO)(PPh(3))(2)] also reacts with IMes·CS(2) and NH(4)PF(6) to yield the analogous product [Ru{κ(2)-SC(H)S(CH=CHC(6)H(4)Me-4)·IMes}Cl(CO)(PPh(3))(2)](+)via the intermediate [Ru(CH=CHC(6)H(4)Me-4)(κ(2)-S(2)C·IMes)(CO)(PPh(3))(2)](+). Structural studies are reported for [Ru(CH=CHC(6)H(4)Me-4)(κ(2)-S(2)C·IPr)(CO)(PPh(3))(2)]PF(6) and [Ru(C(C≡CPh)=CHPh)(κ(2)-S(2)C·ICy)(CO)(PPh(3))(2)]PF(6).     

Synthesis and structural characterization of alkaline-earth-metal bis(amido)silane and lithium oxobis(aminolato)silane complexes

Several of alkaline-earth-metal complexes [(η(2):η(2):μ(N):μ(N)-Li)(+)](2)[{η(2)-Me(2)Si(DippN)(2)}(2)Mg](2-) (4), [η(2)(N,N)-Me(2)Si(DippN)(2)Ca·3THF] (5), [η(2)(N,N)-Me(2)Si(DippN)(2)Sr·THF] (6), and [η(2)(N,N)-Me(2)Si(DippN)(2)Ba·4THF] (7) of a bulky bis(amido)silane ligand were readily prepared by the metathesis reaction of alkali-metal bis(amido)silane [Me(2)Si(DippNLi)(2)] (Dipp = 2,6-i-Pr(2)C(6)H(3)) and alkaline-earth-metal halides MX(2) (M = Mg, X = Br; M = Ca, Sr, Ba, X = I). Alternatively, compounds 5-7 were synthesized either by transamination of M[N(SiMe(3))(2)](2)·2THF (M = Ca, Sr, Ba) and [Me(2)Si(DippNH)(2)] or by transmetalation of Sn[N(SiMe(3))(2)](2), [Me(2)Si(DippNH)(2)], and metallic calcium, strontium, and barium in situ. The metathesis reaction of dilithium bis(amido)silane [Me(2)Si(DippNLi)(2)] and magnesium bromide in the presence of oxygen afforded, however, an unusual lithium oxo polyhedral complex {[(DippN(Me(2)Si)(2))(μ-O)(Me(2)Si)](2)(μ-Br)(2)[(μ(3)-Li)·THF](4)(μ(4)-O)(4)(μ(3)-Li)(2)} (8) with a square-basket-shaped core Li(6)Br(2)O(4) bearing a bis(aminolato)silane ligand. All complexes were characterized using (1)H, (13)C, and (7)Li NMR and IR spectroscopy, in addition to X-ray crystallography.     

Investigation of porous Ni-based metal-organic frameworks containing paddle-wheel type inorganic building units via high-throughput methods

In the search of Ni based metal-organic frameworks (MOFs) containing paddle-wheel type building units, three chemical systems Ni(2+)/H(n)L/base/solvent with H(n)L = H(3)BTC (1,3,5-benzenetricarboxylic acid), H(3)BTB (4,4',4',-benzene-1,3,5-triyl-tris(benzoic acid)), and H(2)BDC (terephthalic acid) were investigated using high-throughput (HT) methods. In addition to the conventional heating, for the first time HT microwave assisted synthesis of MOFs was carried out. Six new compounds were discovered, and their fields of formation were established. In the first system, H(3)BTC was employed and a comprehensive HT-screening of compositional and process parameters was conducted. The synthesis condition for the Ni paddle-wheel unit was determined and two compounds [Ni(3)(BTC)(2)(Me(2)NH)(3)]·(DMF)(4)(H(2)O)(4) (1a) and [Ni(6)(BTC)(2)(DMF)(6)(HCOO)(6)] (1b) were discovered (Me(2)NH = dimethylamine, DMF = dimethylformamide). In the second system, the use of the extended tritopic linker H(3)BTB and the synthesis conditions for the paddle-wheel units led to the porous MOF, [Ni(3)(BTB)(2)(2-MeIm)(1.5)(H(2)O)(1.5)]·(DMF)(9)(H(2)O)(6.5) (2), (2-MeIm = 2-methylimidazole). This compound shows a selective adsorption of H(2)O and H(2) with a strong hysteresis. In the third system, H(2)BDC was used, and the base (DABCO) was incorporated as a bridging ligand into all structures. Thus, two pillared layered porous MOFs [Ni(2)(BDC)(2)(DABCO)]·(DMF)(4)(H(2)O)(1.5) (3a) and [Ni(2)(BDC)(2)(DABCO)]·(DMF)(4)(H(2)O)(4) (3b) as well as a layered compound [Ni(BDC)(DABCO)]·(DMF)(1.5)(H(2)O)(2) (3c) were isolated. The 3a and 3b polymorphs of the [Ni(2)(BDC)(2)(DABCO)] framework can be selectively synthesized. The combination of microwave assisted heating, low overall concentration, stirring of the reaction mixtures, and an excess of DABCO yields a highly crystalline pure phase of 3b. The fields of formation of all compounds were established, and scale-up was successfully performed for 1b, 2, 3a, 3b, and 3c. All compounds were structurally characterized. In addition to IR, elemental and TG analyses, gas and vapor sorption experiments were carried out.     

Theoretical insights into the ferromagnetic coupling in oxalato-bridged chromium(III)-cobalt(II) and chromium(III)-manganese(II) dinuclear complexes with aromatic diimine ligands

Two novel heterobimetallic complexes of formula [Cr(bpy)(ox)(2)Co(Me(2)phen)(H(2)O)(2)][Cr(bpy)(ox)(2)]·4H(2)O (1) and [Cr(phen)(ox)(2)Mn(phen)(H(2)O)(2)][Cr(phen)(ox)(2)]·H(2)O (2) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, and Me(2)phen = 2,9-dimethyl-1,10-phenanthroline) have been obtained through the "complex-as-ligand/complex-as-metal" strategy by using Ph(4)P[CrL(ox)(2)]·H(2)O (L = bpy and phen) and [ML'(H(2)O)(4)](NO(3))(2) (M = Co and Mn; L' = phen and Me(2)phen) as precursors. The X-ray crystal structures of 1 and 2 consist of bis(oxalato)chromate(III) mononuclear anions, [Cr(III)L(ox)(2)](-), and oxalato-bridged chromium(III)-cobalt(II) and chromium(III)-manganese(II) dinuclear cations, [Cr(III)L(ox)(μ-ox)M(II)L'(H(2)O)(2)](+)[M = Co, L = bpy, and L' = Me(2)phen (1); M = Mn and L = L' = phen (2)]. These oxalato-bridged Cr(III)M(II) dinuclear cationic entities of 1 and 2 result from the coordination of a [Cr(III)L(ox)(2)](-) unit through one of its two oxalato groups toward a [M(II)L'(H(2)O)(2)](2+) moiety with either a trans- (M = Co) or a cis-diaqua (M = Mn) configuration. The two distinct Cr(III) ions in 1 and 2 adopt a similar trigonally compressed octahedral geometry, while the high-spin M(II) ions exhibit an axially (M = Co) or trigonally compressed (M = Mn) octahedral geometry in 1 and 2, respectively. Variable temperature (2.0-300 K) magnetic susceptibility and variable-field (0-5.0 T) magnetization measurements for 1 and 2 reveal the presence of weak intramolecular ferromagnetic interactions between the Cr(III) (S(Cr) = 3/2) ion and the high-spin Co(II) (S(Co) = 3/2) or Mn(II) (S(Mn) = 5/2) ions across the oxalato bridge within the Cr(III)M(II) dinuclear cationic entities (M = Co and Mn) [J = +2.2 (1) and +1.2 cm(-1) (2); H = -JS(Cr)·S(M)]. Density functional electronic structure calculations for 1 and 2 support the occurrence of S = 3 Cr(III)Co(II) and S = 4 Cr(III)Mn(II) ground spin states, respectively. A simple molecular orbital analysis of the electron exchange mechanism suggests a subtle competition between individual ferro- and antiferromagnetic contributions through the σ- and/or π-type pathways of the oxalato bridge, mainly involving the d(yz)(Cr)/d(xy)(M), d(xz)(Cr)/d(xy)(M), d(x(2)-y(2))(Cr)/d(xy)(M), d(yz)(Cr)/d(xz)(M), and d(xz)(Cr)/d(yz)(M) pairs of orthogonal magnetic orbitals and the d(x(2)-y(2))(Cr)/d(x(2)-y(2))(M), d(xz)(Cr)/d(xz)(M), and d(yz)(Cr)/d(yz)(M) pairs of nonorthogonal magnetic orbitals, which would be ultimately responsible for the relative magnitude of the overall ferromagnetic coupling in 1 and 2.