Controlling the nature of mixed (phthalocyaninato)(porphyrinato) rare-earth(III) double-decker complexes: the effects of nonperipheral alkoxy substitution of the phthalocyanine ligand

The half-sandwich rare-earth complexes [M(III)(acac)(TClPP)] (M = Sm, Eu, Y; TClPP = meso-tetrakis(4-chlorophenyl)porphyrinate; acac = acetylacetonate), generated in situ from [M(acac)3] x n H2O and H2(TClPP), were treated with 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine [H2{Pc(alpha-OC5H11)4}] (Pc = phthalocyaninate) under reflux in n-octanol to yield both the neutral nonprotonated and protonated (phthalocyaninato)(porphyrinato) rare-earth double-decker complexes, [M(III){Pc(alpha-OC5H11)4}(TClPP)] (1-3) and [M(III)H{Pc(alpha-OC5H11)4}(TClPP)] (4-6), respectively. In contrast, reaction of [Y(III)(acac)(TClPP)] with 1,4,8,11,15,18,22,25-octakis(1-butyloxy)phthalocyanine [H2Pc(alpha-OC4H9)8] gave only the protonated double-decker complex [Y(III)H{Pc(alpha-OC4H9)8}(TClPP)] (7). These observations clearly show the importance of the number and positions of substituents on the phthalocyanine ligand in controlling the nature of the (phthalocyaninato)(porphyrinato) rare-earth double-deckers obtained. In particular, alpha-alkoxylation of the phthalocyanine ligand is found to stabilize the protonated form, a fact supported by molecular-orbital calculations. A combination of mass spectrometry, NMR, UV-visible, near-IR, MCD, and IR spectroscopy, and X-ray diffraction analyses, facilitated the differentiation of the newly prepared neutral nonprotonated and protonated double-decker complexes. The crystal structure of the protonated form has been determined for the first time.     

Location of the hole and acid proton in neutral nonprotonated and protonated mixed (phthalocyaninato)(porphyrinato) yttrium double-decker complexes: density functional theory calculations

The location of the hole and acid proton in neutral nonprotonated and protonated mixed (phthalocyaninato)(porphyrinato) yttrium double-decker complexes, respectively, is studied on the basis of density functional theory (DFT) calculations on the molecular structures, molecular orbitals, atomic charges, and electronic absorption and infrared spectra of the neutral, reduced, and two possible protonated species of a mixed (phthalocyaninato)(porphyrinato) yttrium compound: [(Pc)Y(Por)], [(Pc)Y(Por)]-, [(HPc)Y(Por)], and [(Pc)Y(HPor)], respectively. When the neutral [(Pc)Y(Por)] is reduced to [(Pc)Y(Por)]-, the calculated results on the molecular structure, atomic charge, and electronic absorption and infrared spectra show that the added electron has more influence on the Pc ring than on its Por counterpart, suggesting that the location of the hole is on the Pc ring in neutral [(Pc)Y(Por)]. Nevertheless, comparison of the calculation results on the structure, orbital composition, charge distribution, and electronic absorption and infrared spectra between [(HPc)Y(Por)] and [(Pc)Y(HPor)] leads to the conclusion that the acid proton in the protonated mixed (phthalocyaninato)(porphyrinato) yttrium compound should be localized on the Por ring rather than the Pc ring, despite the localization of the hole on the Pc ring in [(Pc)Y(Por)]. This result is in line with the trend revealed by comparative studies of the X-ray single-crystal molecular structures between [MIII{Pc(alpha-OC5H11)4}(TClPP)] and [M(III)H{Pc(alpha-OC5H11)4}(TClPP)] (H2TClPP=5,10,15,20-tetrakis(4-chlorophenyl)porphyrin; M=Sm, Eu). The present work not only represents the first systemic DFT study on the structures and properties of mixed (phthalocyaninato)(porphyrinato) yttrium double-decker complexes, but more importantly sheds further light on the nature of protonated bis(tetrapyrrole) rare-earth complexes.     

Vibrational spectra of mixed (phthalocyaninato)(porphyrinato) yttrium(III) double-decker complexes: Density functional theory calculations

The vibrational (IR and Raman) spectra of neutral and reduced mixed (phthalocyaninato)(porphyrinato) yttrium(III) double-decker complexes Y(Pc)(Por) and [Y(Pc)(Por)]⁻ [the simplified models of mixed (phthalocyaninato)(porphyrinato) rare earth(III) complexes] are studied using density functional theory (DFT) calculations. The simulated IR and Raman spectra of Y(Pc)(Por) are compared with the experimental IR spectrum of Tb(Pc)(TClPP) and Raman spectrum of Y(Pc)(TClPP), respectively, and many bands can acceptably fit in spite of the different species. On the basis of comparison with the simulated spectra of PbPc and PbPor together with the assistance of normal coordinate analysis, the calculated frequencies in their IR and Raman spectra are identified in terms of the vibrational mode of different ligand for the first time. The calculated frequency at 1048 cm⁻¹ in the IR spectrum of [Y(Pc)(Por)]⁻ with contribution from both Pc and Por vibrational modes is the characteristic IR vibrational mode of the reduced double-decker, while the characteristic IR vibrational mode of Y(Pc)(Por) attributed from the vibration of phthalocyanine monoanion radical Pc⁻ appears at 1257 cm⁻¹. In line with our previous experimental findings that the Raman spectra of M(Pc)(TPP) and M(Pc)(TClPP) are dominated by the Pc vibrational modes, theoretical calculations indicate that most of the Raman vibrational modes contributed from Por ring are covered up by those of Pc ring and thus are hard to be recognized in the Raman spectra of [Y(Pc)(Por)]⁻ and Y(Pc)(Por) due to their much weaker intensity in comparison with that of Pc ligand. Comparison in the IR and Raman spectra between [Y(Pc)(Por)]⁻ and Y(Pc)(Por) also suggests the localization of hole on the Pc ring in the neutral double-decker Y(Pc)(Por). The present work, representing the first detailed DFT study on the vibrational spectra of mixed (phthalocyaninato)(porphyrinato) rare earth(III) double-decker complexes, is useful in helping to understand the vibrational spectroscopic properties of this series of mixed tetrapyrrole ring complexes.     

Ferrocene-decorated (phthalocyaninato)(porphyrinato) double- and triple-decker rare earth complexes: synthesis, structure, and electrochemical properties

A series of four mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes (Pc)M[Por(Fc)(2)] [Pc = phthalocyaninate; Por(Fc)(2) = 5,15-di(ferrocenyl)-porphyrinate; M = Eu (1), Y (2), Ho (3), Lu (4)] and their europium(III) triple-decker counterpart (Pc)Eu(Pc)Eu[Por(Fc)(2)] (5), each with two ferrocenyl units at the meso-positions of their porphyrin ligands, have been designed and prepared. The double- and triple-decker complexes 1-5 were characterized by elemental analysis and various spectroscopic methods. The molecular structures of two double-deckers 1 and 4 were also determined by single-crystal X-ray diffraction analysis. Electrochemical studies of these novel sandwich complexes revealed two consecutive ferrocene-based one-electron oxidation waves, suggesting the effective electronic coupling between the two ferrocenyl units. Nevertheless, the separation between the two consecutive ferrocene-based oxidation waves increases from 1 to 4, along with the decrease of rare earth ionic radius, indicating the effect of rare earth size on tuning the coupling between the two ferrocenyl units. Furthermore, the splitting between the two ferrocene-based one-electron oxidations for triple-decker 5 is even smaller than that for 1, showing that the electronic interaction between the two ferrocene centers can also be tuned through changing the linking sandwich framework from double-decker to triple-decker. For further understanding of the electronic coupling between ferrocenyl groups, DFT calculation is carried out to clarify the electronic delocalization and the molecular orbital distribution in these double-decker complexes.     

Constructing sandwich-type rare Earth double-decker complexes with N-confused porphyrinato and phthalocyaninato ligands

Reaction of the half-sandwich complexes M(III)(Pc)(acac) (M = La, Eu, Y, Lu; Pc = phthalocyaninate; acac = acetylacetonate) with the metal-free N-confused 5,10,15,20-tetrakis[(4-tert-butyl)phenyl]porphyrin (H(2)NTBPP) or its N2-position methylated analogue H(CH(3))NTBPP in refluxing 1,2,4-trichlorobenzene (TCB) led to the isolation of M(III)(Pc)(HNTBPP) (M = La, Eu, Y, Lu) or Y(III)(Pc)[(CH(3))NTBPP] in 8-15% yield. These represent the first examples of sandwich-type rare earth complexes with N-confused porphyrinato ligands. The complexes were characterized with various spectroscopic methods and elemental analysis. The molecular structures of four of these double-decker complexes were also determined by single-crystal X-ray diffraction analysis. In each of these complexes, the metal center is octa-coordinated by four isoindole nitrogen atoms of the Pc ligand, three pyrrole nitrogen atoms, and the inverted pyrrole carbon atom of the HNTBPP or (CH(3))NTBPP ligand, forming a distorted coordination square antiprism. For Eu(III)(Pc)(HNTBPP), the two macrocyclic rings are further bound to a CH(3)OH molecule through two hydrogen bonds formed between the hydroxyl group of CH(3)OH and an aza nitrogen atom of the Pc ring or the inverted pyrrole nitrogen atom of the HNTBPP ring, respectively. The location of the acidic proton at the inverted pyrrole nitrogen atom (N2) of the protonated double-deckers was revealed by (1)H NMR spectroscopy.     

Optically active mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes. Synthesis, spectroscopy, and effective chiral information transfer

With the view to creating novel sandwich-type tetrapyrrole rare earth complexes toward potential applications in material science and chiral catalysis, two new optically active mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes with both (R)- and (S)-enantiomers [M(2)(Pc)(2)(TCBP)] {TCBP = Meso-tetrakis [3,4-(11,12:13,14-di(1',2'-naphtho)-1,4,7,10,15,18-hexaoxacycloeicosa-2,11,13-triene)-phenyl] porphyrinate; M = Eu (1), Y (2)} have been designed and prepared by treating optically active metal free porphyrin (R)-/(S)-H(2)TCBP with M(Pc)(2) in the presence of corresponding M(acac)(3)·nH(2)O (acac = acetylacetonate) in refluxing 1,2,4-trichlorobenzene (TCB). These novel mixed ring rare earth triple-decker compounds were characterized by a wide range of spectroscopic methods including MS, (1)H NMR, IR, electronic absorption, and magnetic circular-dichroism (MCD) spectroscopic measurements in addition to elemental analysis. Perfect mirror image relationship was observed in the Soret and Q absorption regions in the circular-dichroism (CD) spectra of the (R)- and (S)-enantiomers, indicating the optically active nature of these two mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes. This result reveals the effective chiral information transfer from the peripheral chiral binaphthyl units to the porphyrin and phthalocyanine chromophores in the triple-decker molecule because of the intense π-π interaction between porphyrin and phthalocyanine rings. In addition, their electrochemical properties have also been investigated by cyclic voltammetry (CV).     

Synthesis, characterization, and DNA-binding and -photocleavage properties of water-soluble lanthanide porphyrinate complexes

A series of cationic lanthanide porphyrinate complexes of the general formula [(Por)Ln(H(2)O)(3)](+) (Ln(3+)=Yb(3+) and Er(3+)) were synthesized in moderate yields through the interaction of meso-pyridyl-substituted porphyrin free bases (H(2)Por) with [Ln{N(SiMe(3))(2)}(3)]·x[LiCl(thf)(3)], and the corresponding neutral derivatives [(Por)Ln(L(OMe))] (L(OMe)(-)=[(η(5)-C(5)H(5))Co{P(=O)(OMe)(2)}(3)](-)) were also prepared from [(Por)Ln(H(2)O)(3)](+) by the addition of the tripodal anion, L(OMe)(-), an effective encapsulating agent for lanthanide ions. Furthermore, the water-soluble lanthanide(III) porphyrinate complexes--including [(cis-DMPyDPP)Yb(H(2)O)(3)]Cl(3) (cis-DMPyDPP=5,10-bis(N-methylpyridinium-4'-y1)-15,20-di(phenyl)porphyrin), [(trans-DMPyDPP)Yb(H(2)O)(3)]Cl(3) (trans-DMPyDPP=5,15-bis(N-methylpyridinium-4'-y1)-10,20-di(phenyl)porphyrin), [(TMPyP)Yb(L(OMe))]I(4), and [(TMPyP)Er(L(OMe))]I(4) (TMPyP=tetrakis(N-methylpyridinium-4-y1)porphyrin)--were obtained by methylation of the corresponding complexes with methyl iodide and unambiguously characterized. The binding interactions and photocleavage activities of the water-soluble lanthanide(III) porphyrinate complexes towards DNA were investigated by UV-visible, fluorescence, and near-infrared luminescence spectroscopy, as well as circular dichroism and gel electrophoresis.     

Investigation of rational syntheses of heteroleptic porphyrinic lanthanide (europium, cerium) triple-decker sandwich complexes

The use of lanthanide triple-decker sandwich molecules containing porphyrins and phthalocyanines in molecular information storage applications requires the ability to attach monomeric triple deckers or arrays of triple deckers to electroactive surfaces. Such applications are limited by existing methods for preparing triple deckers. The reaction of a lanthanide porphyrin half-sandwich complex ((Por)M(acac)) with a dilithium phthalocyanine (PcLi2) in refluxing 1,2,4-trichlorobenzene (bp 214 degrees C) affords a mixture of triple deckers of composition (Pc)M(Pc)M(Por), (Por)M(Pc)M(Por), and (Pc)M(Por)M(Pc). We have investigated more directed methods for preparing triple deckers of a given type with distinct metals in each layer. Application of the method of Weiss, which employs reaction of a (Por)M(acac) species with a lanthanide double decker in refluxing 1,2,4-trichlorobenzene, afforded the desired triple decker in some cases but a mixture of triple deckers in others. The approach we developed employs in situ formation of the lanthanide reagent EuCl[N(SiMe3)2]2 or CeI[N(SiMe3)2]2, which upon reaction with a porphyrin affords the half-sandwich complex (Por)EuX or (Por)CeX' (X = Cl, N(SiMe3)2; X' = I, N(SiMe3)2). Subsequent reaction with PcLi2 gives the double decker (Por)M(Pc). The (Por(1))EuX half-sandwich complex gave the desired triple decker upon reaction with (Pc)Eu(Pc) but little of the desired product upon reaction with (Por(2))Eu(Pc). The (Por(1))CeX' half-sandwich complex reacted with europium double deckers (e.g., (tBPc)Eu(Por(2)), (tBPc)2Eu) to give the triple deckers (Por(1))Ce(tBPc)Eu(Por(2)) and (Por(1))Ce(tBPc)Eu(tBPc) in a rational manner (tB = tetra-tert-butyl). The reactions yielding the half-sandwich, double-decker, and triple-decker complexes were performed in refluxing bis(2-methoxyethyl) ether (bp 162 degrees C). The porphyrins incorporated in the various triple deckers include meso-tetrapentylporphyrin, meso-tetra-p-tolylporphyrin, octaethylporphyrin, and meso-tetraarylporphyrins bearing iodo, ethynyl, or iodo and ethynyl substituents. The triple deckers bearing iodo and/or ethynyl substituents constitute useful building blocks for information storage applications.     

Studies of "pinwheel-like" bis[1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato] rare earth(III) double-decker complexes

Homoleptic bis(phthalocyaninato) rare-earth double-deckers complexes [M(III)[Pc(alpha-OC5H11)4]2] (M = Eu, Y, Lu; Pc(alpha-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninate) have been prepared by treating the metal-free phthalocyanine H2Pc(alpha-OC5H11)4 with the corresponding M(acac)3.nH2O (acac = acetylacetonate) in refluxing n-octanol. Due to the C4h symmetry of the Pc(alpha-OC5H11)4 ligand and the double-decker structure, all the reactions give a mixture of two stereoisomers with C4h and D4 symmetry. The former isomer, which is a major product, can be partially separated by recrystallization due to its higher crystallinity. The molecular structure of the major isomer of the Y analogue has been determined by single-crystal X-ray diffraction analysis. The metal center is eight-coordinate bound to the isoindole nitrogen atoms of the two phthalocyaninato ligands, forming a distorted square antiprism. Such an arrangement leads to an interesting pinwheel structure when viewed along the C4 axis, which assumes a very unusual S8 symmetry. The major isomers of all these double-deckers have also been characterized with a wide range of spectroscopic methods. A systematic investigation of their electronic absorption and electrochemical data reveals that the pi-pi interaction between the two Pc(alpha-OC5H11)4 rings is weaker than that for the corresponding unsubstituted or beta-substituted bis(phthalocyaninato) analogues.     

Heteroleptic bis(phthalocyaninato) europium(III) complexes fused with different numbers of 15-crown-5 moieties. Synthesis, spectroscopy, electrochemistry, and supramolecular structure

A series of heteroleptic bis(phthalocyaninato) europium(III) complexes, namely, Eu(Pc)[Pc(15C5)] (2), Eu(Pc)[Pc(opp-15C5)2] (3), Eu(Pc)[Pc(adj-15C5)2] (4), Eu(Pc)[Pc(15C5)3] (5), and Eu(Pc)[Pc(15C5)4] (6) [Pc = unsubstituted phthalocyaninate; Pc(15C5) = 2,3-(15-crown-5)phthalocyaninate; Pc(opp-15C5)2 = 2,3,16,17-bis(15-crown-5)phthalocyaninate; Pc(adj-15C5)2 = 2,3,9,10-bis(15-crown-5)phthalocyaninate; Pc(15C5)3 = 2,3,9,10,16,17-tris(15-crown-5)phthalocyaninate, Pc(15C5)4 = 2,3,9,10,16,17,24,25-tetrakis(15-crown-5)phthalocyaninate], with one, two, three, and four 15-crown-5 voids attached at different positions of one of the two phthalocyaninato ligands in the double-decker molecules, have been devised and prepared by Eu(Pc)(acac)-induced (Hacac = acetylacetone) mixed cyclization of the two corresponding phthalonitriles in the presence of organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in n-pentanol. For the purpose of comparative studies, homoleptic counterparts Eu(Pc)2 (1) and Eu[Pc(15C5)4]2 (7) have also been prepared. These sandwich double-decker complexes have been characterized by a wide range of spectroscopic methods in addition to elemental analysis. Their electrochemistry has also been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The molecular structure of Eu(Pc)[Pc(15C5)4] (6) has been determined by X-ray diffraction analysis. Their supramolecular structure-formation properties, in particular for compounds 5 and 6 in the presence of potassium ions, have also been comparatively studied for the purpose of future functional investigation.     

Heteroleptic rare earth double-decker complexes with naphthalocyaninato and phthalocyaninato ligands. General synthesis, spectroscopic, and electrochemical characteristics

A novel one-pot procedure starting from the corresponding M(acac)3 x nH2O, metal-free phthalocyanine H2Pc', and naphthalonitrile in the presence of DBU in n-octanol has been developed to prepare heteroleptic (naphthalocyaninato)(phthalocyaninato) rare earth double-decker complexes. A series of six sandwich compounds with different naphthalocyaninato ligands, phthalocyaninato ligands, and central rare earth metals, namely, Sm[Nc(tBu)4](Pc) [Nc(tBu)4 = 3(4),12(13),21(22),30(31)-tetra(tert-butyl)naphthalocyaninato; Pc = unsubstituted phthalocyaninato] (1), Sm(Nc)(Pc') [Pc' = Pc(OC5H11)4, Pc(OC8H17)8; Nc = 2,3-naphthalocyaninato; Pc(OC5H11)4 = 2(3),9(10),16(17),24(25)-tetrakis(3-pentyloxy)phthalocyaninato; Pc(OC8H17)8 = 2,3,9,10,16,17,24,25-octakis(octyloxy)phthalocyaninato] (2, 3), and M(Nc)[Pc(alpha-OC5H11)4] [M = Sm, Eu, Y; Pc(alpha-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato] (4-6), have been isolated in good yields from this one-pot procedure demonstrating the generality of this synthetic pathway. In addition to spectroscopic analyses, the electrochemistry of these novel compounds has also been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods.     

Structures and spectroscopic properties of bis(phthalocyaninato) yttrium and lanthanum complexes: theoretical study based on density functional theory calculations

Density functional theory (DFT) calculations were carried out to describe the molecular structures, molecular orbitals, atomic charges, UV-vis absorption spectra, IR, and Raman spectra of bis(phthalocyaninato) rare earth(III) complexes M(Pc)(2) (M = Y, La) as well as their reduced products [M(Pc)(2)](-) (M = Y, La). Good consistency was found between the calculated results and experimental data. Reduction of the neutral M(Pc)(2) to [M(Pc)(2)]- induces the reorganization of their orbitals and charge distribution and decreases the inter-ring interaction. With the increase of ionic size from Y to La, the inter-ring distance of both the neutral and reduced double-decker complexes M(Pc)(2) and [M(Pc)(2)](-) (M = Y, La) increases, the inter-ring interaction and splitting of the Q bands decrease, and corresponding bands in the IR and Raman spectra show a red shift. The orbital energy level and orbital nature of the frontier orbitals are also described and explained in terms of atomic character. The present work, representing the first systemic DFT study on the bis(phthalocyaninato) yttrium and lanthanum complexes sheds further light on clearly understanding structure and spectroscopic properties of bis(phthalocyaninato) rare earth complexes.     

Sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes with decreased molecular symmetry of Cs: single crystal structure and self-assembled nano-structure

Two novel sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes with decreased molecular symmetry of Cs M(Pc)[D(NHC(8)H(17))(2)PP] [M = Eu, Lu; Pc = unsubstituted phthalocyaninate; D(NHC(8)H(17))(2)PP = 5,10-di(phenyl)-15,20-di(4-octylamino-phenyl)porphyrinate] (1, 2) have been designed, prepared, and characterized. The single crystal and molecular structure of the Eu analogue has been determined by X-ray diffraction analysis, revealing the head-to-tail supramolecular chains formed from closely bound double-decker molecules depending on the N-H-N hydrogen bonds between one octyl-substituted amidocyanogen group attached at the p-position of meso-attached phenyl group of the porphyrin ligand in the mixed ring double-decker molecule and one aza-nitrogen atom of the phthalocyanine ring in the neighboring double-decker molecule in a zigzag form. Their self-assembled nano-structures have been investigated by transmission electronic microscopy (TEM) and scanning electronic microscopy (SEM). Intermolecular H-N-H hydrogen bonding interaction leads to the formation of nano-structures with fusiform morphology with 220-250 nm average width and about 10 μm length for 1 and 300 nm width and 3-5 μm length for 2, respectively, revealing the effect of molecular size in the direction perpendicular to the tetrapyrrole ring on the dimensions of self-assembled nano-structures.     

Synthesis, structure and optical properties of rare-earth benzene carboxylates

Two series of rare-earth isophthalates of the general formula, [M(2)(H(2)O)][{C(6)H(4)(COO)(2)}(2){C(6)H(4)(COOH)(COO)}(2)].H(2)O, M=La (I), Pr (Ia), and Nd (Ib) and [M(2)(H(2)O)(2)][{C(6)H(4)(COO)(2)}(3)].H(2)O, M=Y (II), Gd (IIa), and Dy (IIb) have been prepared by the reaction of the corresponding trivalent lanthanide salts and isophthalic acid under mild hydrothermal conditions. The La (I), Pr (Ia) and Nd (Ib) have MO(9) polyhedra connected to the isophthalate anions forming a two-dimensional structure, whereas Y (II), Gd (IIa) and Dy (IIb) have MO(7) and MO(8) polyhedral units connected to the isophthalate anions forming a different, but related two-dimensional structure. Both the structures are stabilized by hydrogen bonding and pi...pi/CH...pi interactions. Partial substitution of Eu and Tb (2 and 4%) at the La (I) and Y (II) sites give rise to characteristic red/pink or green luminescence, indicating a ligand-sensitized metal-centered emission. The Nd (Ib) compound shows interesting UV and blue emission through an up-conversion process.     

Transition metal complexes with wide-angle dithio-, diseleno- and ditelluroethers: properties and structural systematics

The ligands o-C(6)H(4)(CH(2)EMe)(2) (E = S or Se) have been prepared and characterised spectroscopically. A systematic study of the coordination chemistry of these, together with the telluroether analogue, o-C(6)H(4)(CH(2)TeMe)(2), with late transition metal centers has been undertaken. The planar complexes [MCl(2){o-C(6)H(4)(CH(2)SMe)(2)}] and [M{o-C(6)H(4)(CH(2)EMe)(2)}(2)](PF(6))(2) (M = Pd or Pt; E = S or Se), the distorted octahedral [RhCl(2){o-C(6)H(4)(CH(2)EMe)(2)}(2)]Y (E = S or Se: Y = PF(6); E = Te: Y = Cl) and [RuCl(2){o-C(6)H(4)(CH(2)EMe)(2)}(2)] (E = S, Se or Te), the dithioether-bridged binuclear [{RuCl(2)(p-cymene)}(2){micro-o-C(6)H(4)(CH(2)SMe)(2)}] and the tetrahedral [M'{o-C(6)H(4)(CH(2)EMe)(2)}(2)]BF(4) (M' = Cu or Ag; E = S, Se or Te) have been obtained and characterised by IR and multinuclear NMR spectroscopy ((1)H, (63)Cu, (77)Se{(1)H}, (125)Te{(1)H} and (195)Pt), electrospray MS and microanalyses. Crystal structures of the parent o-C(6)H(4)(CH(2)SMe)(2) and seven complexes are described, which show three different stereoisomeric forms for the chelated ligands, as well as the first example of a bridging coordination mode in [{RuCl(2)(p-cymene)}(2){micro-o-C(6)H(4)(CH(2)SMe)(2)}]. These studies reveal the consequences of the sterically demanding o-xylyl backbone, which typically leads to unusually obtuse E-M-E chelate angles of approximately 100 degrees .     

Molecular nitrides with titanium and rare-earth metals

A series of titanium-group 3/lanthanide metal complexes have been prepared by reaction of [{Ti(η(5)-C(5)Me(5))(μ-NH)}(3)(μ(3)-N)] (1) with halide, triflate, or amido derivatives of the rare-earth metals. Treatment of 1 with metal halide complexes [MCl(3)(thf)(n)] or metal trifluoromethanesulfonate derivatives [M(O(3)SCF(3))(3)] at room temperature affords the cube-type adducts [X(3)M{(μ(3)-NH)(3)Ti(3)(η(5)-C(5)Me(5))(3)(μ(3)-N)}] (X = Cl, M = Sc (2), Y (3), La (4), Sm (5), Er (6), Lu (7); X = OTf, M = Y (8), Sm (9), Er (10)). Treatment of yttrium (3) and lanthanum (4) halide complexes with 3 equiv of lithium 2,6-dimethylphenoxido [LiOAr] produces the aryloxido complexes [(ArO)(3)M{(μ(3)-NH)(3)Ti(3)(η(5)-C(5)Me(5))(3)(μ(3)-N)}] (M = Y (11), La (12)). Complex 1 reacts with 0.5 equiv of rare-earth bis(trimethylsilyl)amido derivatives [M{N(SiMe(3))(2)}(3)] in toluene at 85-180 °C to afford the corner-shared double-cube nitrido compounds [M(μ(3)-N)(3)(μ(3)-NH)(3){Ti(3)(η(5)-C(5)Me(5))(3)(μ(3)-N)}(2)] (M = Sc (13), Y (14), La (15), Sm (16), Eu (17), Er (18), Lu (19)) via NH(SiMe(3))(2) elimination. A single-cube intermediate [{(Me(3)Si)(2)N}Sc{(μ(3)-N)(2)(μ(3)-NH)Ti(3)(η(5)-C(5)Me(5))(3)(μ(3)-N)}] (20) was obtained by the treatment of 1 with 1 equiv of the scandium bis(trimethylsilyl)amido derivative [Sc{N(SiMe(3))(2)}(3)]. The X-ray crystal structures of 2, 7, 11, 14, 15, and 19 have been determined. The thermal decomposition in the solid state of double-cube nitrido complexes 14, 15, and 18 has been investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements, as well as by pyrolysis experiments at 1100 °C under different atmospheres (Ar, H(2)/N(2), NH(3)) for the yttrium complex 14.     

Synthesis, crystal structures, and magnetic properties of a new family of heterometallic cyanide-bridged Fe(III)2M(II)2 (M=Mn, Ni, and Co) square complexes

New heterobimetallic tetranuclear complexes of formula [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Mn(II)(bpy)(2)](2)(ClO(4))(2)·CH(3)CN (1), [Fe(III){HB(pz)(3)}(CN)(2)(μ-CN)Ni(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (2a), [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Ni(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (2b), [Fe(III){HB(pz)(3)}(CN)(2)(μ-CN)Co(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (3a), and [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Co(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (3b), [HB(pz)(3)(-) = hydrotris(1-pyrazolyl)borate, B(Pz)(4)(-) = tetrakis(1-pyrazolyl)borate, dmphen = 2,9-dimethyl-1,10-phenanthroline, bpy = 2,2'-bipyridine] have been synthesized and structurally and magnetically characterized. Complexes 1-3b have been prepared by following a rational route based on the self-assembly of the tricyanometalate precursor fac-[Fe(III)(L)(CN)(3)](-) (L = tridentate anionic ligand) and cationic preformed complexes [M(II)(L')(2)(H(2)O)(2)](2+) (L' = bidentate α-diimine type ligand), this last species having four blocked coordination sites and two labile ones located in cis positions. The structures of 1-3b consist of cationic tetranuclear Fe(III)(2)M(II)(2) square complexes [M = Mn (1), Ni (2a and 2b), Co (3a and 3b)] where corners are defined by the metal ions and the edges by the Fe-CN-M units. The charge is balanced by free perchlorate anions. The [Fe(L)(CN)(3)](-) complex in 1-3b acts as a ligand through two cyanide groups toward two divalent metal complexes. The magnetic properties of 1-3b have been investigated in the temperature range 2-300 K. A moderately strong antiferromagnetic interaction between the low-spin Fe(III) (S = 1/2) and high-spin Mn(II) (S = 5/2) ions has been found for 1 leading to an S = 4 ground state (J(1) = -6.2 and J(2) = -2.7 cm(-1)), whereas a moderately strong ferromagnetic interaction between the low-spin Fe(III) (S = 1/2) and high-spin Ni(II) (S = 1) and Co(II) (S = 3/2) ions has been found for complexes 2a-3b with S = 3 (2a and 2b) and S = 4 (3a and 3b) ground spin states [J(1) = +21.4 cm(-1) and J(2) = +19.4 cm(-1) (2a); J(1) = +17.0 cm(-1) and J(2) = +12.5 cm(-1) (2b); J(1) = +5.4 cm(-1) and J(2) = +11.1 cm(-1) (3a); J(1) = +8.1 cm(-1) and J(2) = +11.0 cm(-1) (3b)] [the exchange Hamiltonian being of the type H? = -J(S?(i)·S?(j))]. Density functional theory (DFT) calculations have been used to substantiate the nature and magnitude of the exchange magnetic coupling observed in 1-3b and also to analyze the dependence of the exchange magnetic coupling on the structural parameters of the Fe-C-N-M skeleton.     

Hydride mobility in trinuclear sulfido clusters with the core [Rh3(μ-H)(μ3-S)2]: molecular models for hydrogen migration on metal sulfide hydrotreating catalysts

The treatment of [{Rh(μ-SH){P(OPh)(3)}(2)}(2)] with [{M(μ-Cl)(diolef)}(2)] (diolef=diolefin) in the presence of NEt(3) affords the hydrido-sulfido clusters [Rh(3)(μ-H)(μ(3)-S)(2)(diolef){P(OPh)(3)}(4)] (diolef=1,5-cyclooctadiene (cod) for 1, 2,5-norbornadiene (nbd) for 2, and tetrafluorobenzo[5,6]bicyclo[2.2.2]octa-2,5,7-triene (tfb) for 3) and [Rh(2)Ir(μ-H)(μ(3)-S)(2)(cod){P(OPh)(3)}(4)] (4). Cluster 1 can be also obtained by treating [{Rh(μ-SH){P(OPh)(3)}(2)}(2)] with [{Rh(μ-OMe)(cod)}(2)], although the main product of the reaction with [{Ir(μ-OMe)(cod)}(2)] was [RhIr(2)(μ-H)(μ(3)-S)(2)(cod)(2){P(OPh)(3)}(2)] (5). The molecular structures of clusters 1 and 4 have been determined by X-ray diffraction methods. The deprotonation of a hydrosulfido ligand in [{Rh(μ-SH)(CO)(PPh(3))}(2)] by [M(acac)(diolef)] (acac=acetylacetonate) results in the formation of hydrido-sulfido clusters [Rh(3)(μ-H)(μ(3)-S)(2)(CO)(2) (diolef)(PPh(3))(2)] (diolef=cod for 6, nbd for 7) and [Rh(2)Ir(μ-H)(μ(3)-S)(2)(CO)(2)(cod)(PPh(3))(2)] (8). Clusters 1-3 and 5 exist in solution as two interconverting isomers with the bridging hydride ligand at different edges. Cluster 8 exists as three isomers that arise from the disposition of the PPh(3) ligands in the cluster (cis and trans) and the location of the hydride ligand. The dynamic behaviour of clusters with bulky triphenylphosphite ligands, which involves hydrogen migration from rhodium to sulfur with a switch from hydride to proton character, is significant to understand hydrogen diffusion on the surface of metal sulfide hydrotreating catalysts.     

Isolation and Spectroscopic Characterization of Protonated Mixed [Tetrakis (4-pyridyl)porphyrinato] (phthalocyaninato)Rare Earth (Ⅲ)Double-decker Compounds

IntroductionThe homoleptic sandwich~type porphyrinato and phthalocyaninato metal complexesRE (P) z and RE2 (P) 3 (RE =rare earth 1 P = Por or Pc) have been intensively studied over sev-eral decades due to their potential application in non-linear optical (NLO) materials, molecu-lar electronic and magnetic ..te.i.l.L1--l6j.The double-deckers have also aroused a growing interest as structural and spectroscopicsynthetic models for the dimmer of bacteriochlorophyl1 molecules in bacterial pho…     

First complexes of scandium and yttrium with NNO and NNS heteroscorpionate ligands

The reaction of ScCl(3)(THF)(3) or YCl(3) in a 1:1 molar ratio under reflux for 8 h with [{Li(bdmpza)(H(2)O)}(4)] [bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate], [{Li(bdmpzdta)(H(2)O)}(4)] [bdmpzdta = bis(3,5-dimethylpyrazol-1-yl)dithioacetate], and (Hbdmpze) [bdmpze = 2,2-bis(3,5-dimethylpyrazol-1-yl)ethoxide] affords the corresponding complexes [MCl(2)(kappa(3)-bdmpzx)(THF)] (x = a, M = Sc (1), Y (2); x = dta, M = Sc (3), Y (4); x = e, M = Sc (5), Y (6)). However, when the reaction was carried out for 1 h under reflux between ScCl(3)(THF)(3) and [{Li(bdmpzdta)(H(2)O)}(4)], a new anionic complex [Li(THF)(4)][ScCl(3)(kappa(3)-bdmpzdta)] (7) was obtained. Reaction of [{Li(bdmpza)(H(2)O)}(4)] with YCl(3) in a 2:1 molar ratio under reflux for 8 h gave the complex [YCl(kappa(3)-bdmpza)(2)] (8). The same reaction, but with the lithium compound [{Li(bdmpzdta)(H(2)O)}(4)], led to the formation of an anionic complex [Li(THF)(4)][YCl(3)(kappa(3)-bdmpzdta)] (9). The X-ray crystal structures of 7 and 9 were established. Finally, the addition of 1 equiv of [{Li(bdmpza)(H(2)O)}(4)] or [{Li(bdmpzdta)(H(2)O)}(4)] to a solution of YCl(3) in THF under reflux, followed by the addition of 1 equiv of 1,10-phenanthroline, resulted in the formation of the corresponding complexes [YCl(2)(kappa(3)-bdmpzx)(phen)] (x = a (10), x = dta (11)). These complexes are the first examples of group 3 metals stabilized by heteroscorpionate ligands. In addition, we have explored the reactivity of some of these complexes with alcohols and amides. For example, the direct reaction of [YCl(2)(kappa(3)-bdmpza)(THF)] (2) with several alcohols gave the alkoxide complexes [YCl(kappa(3)-bdmpza)(OR)] (R = Et (12), iPr (13)). Finally, the reaction between [ScCl(2)(kappa(3)-bdmpzdta)(THF)] (3) or [Li(THF)(4)][ScCl(3)(kappa(3)-bdmpzdta)] (7) and LiN(SiMe(3))(2).Et(2)O in 1:1 and 1:2 molar ratios gave rise to the complexes [ScCl(kappa(3)-bdmpzdta){N(SiMe(3))(2)}] (14) and [Sc(kappa(3)-bdmpzdta){N(SiMe(3))(2)}(2)] (15), respectively.