Biomedical subjects

Timothy J Boyle

Publications and source records attributed to Timothy J Boyle.

14 recordsLinked to original sources

PubMed2006

Solution synthesis of germanium nanowires using a Ge2+ alkoxide precursor.

A simple solution synthesis of germanium (Ge0) nanowires under mild conditions (<400 degrees C and 1 atm) was demonstrated using germanium 2,6-dibutylphenoxide, Ge(DBP)2 (1), as the precursor where DBP = 2,6-OC6H3(C(CH3)3)2. Compound 1, synthesized from Ge(NR2)2 where R = SiMe3 and 2 equiv of DBP-H, was characterized as a mononuclear species by single-crystal X-ray diffraction. Dissolution of 1 in oleylamine, followed by rapid injection into a 1-octadecene solution heated to 300 degrees C under an atmosphere of Ar, led to the formation of Ge0 nanowires. The Ge0 nanowires were characterized by transmission electron microscopy (TEM), X-ray diffraction analysis, and Fourier transform infrared spectroscopy. These characterizations revealed that the nanowires are single crystalline in the cubic phase and coated with oleylamine surfactant. We also observed that the nanowire length (0.1-10 microm) increases with increasing temperature (285-315 degrees C) and time (5-60 min). Two growth mechanisms are proposed based on the TEM images intermittently taken during the growth process as a function of time: (1) self-seeding mechanism where one of two overlapping nanowires serves as a seed, while the other continues to grow as a wire; and (2) self-assembly mechanism where an aggregate of small rods (<50 nm in diameter) recrystallizes on the tip of a longer wire, extending its length.

Germanium↗

PubMed2006

Ultra-wideline 27Al NMR investigation of three- and five-coordinate aluminum environments.

Ultra-wideline 27Al NMR experiments are conducted on coordination compounds with 27Al nuclei possessing immense quadrupolar interactions that result from exceptionally nonspherical coordination environments. NMR spectra are acquired using a methodology involving frequency-stepped, piecewise acquisition of NMR spectra with Hahn-echo or quadrupolar Carr-Purcell Meiboom-Gill (QCPMG) pulse sequences, which is applicable to any half-integer quadrupolar nucleus with extremely broad NMR powder patterns. Despite the large breadth of these central transition powder patterns, ranging from 250 to 700 kHz, the total experimental times are an order of magnitude less than previously reported experiments on analogous complexes with smaller quadrupolar interactions. The complexes examined feature three- or five-coordinate aluminum sites: trismesitylaluminum (AlMes3), tris(bis(trimethylsilyl)amino)aluminum (Al(NTMS2)3), bis[dimethyl tetrahydrofurfuryloxide aluminum] ([Me2-Al(mu-OTHF)]2), and bis[diethyl tetrahydrofurfuryloxide aluminum] ([Et2-Al(mu-OTHF)]2). We report some of the largest 27Al quadrupolar coupling constants measured to date, with values of C(Q)(27Al) of 48.2(1), 36.3(1), 19.9(1), and 19.6(2) MHz for AlMes3, Al(NTMS2)3, [Me2-Al(mu-OTHF)]2, and [Et2-Al(mu-OTHF)]2, respectively. X-ray crystallographic data and theoretical (Hartree-Fock and DFT) calculations of 27Al electric field gradient (EFG) tensors are utilized to examine the relationships between the quadrupolar interactions and molecular structure; in particular, the origin of the immense quadrupolar interaction in the three-coordinate species is studied via analyses of molecular orbitals.

Journal Article↗

PubMed2006

Synthesizing biofunctionalized nanoparticles to image cell signaling pathways.

This minireview outlines the synthetic efforts, from our research group, to produce nanomaterials for use as imaging agents to study cell signaling pathways. An overview of our approach to the synthesis and biofunctionalization of metal, semiconductor, and ceramic nanomaterials is presented. The probes investigated include coinage metals, Cd-based, Ge(o), naturally occurring fluorescent (NOF) minerals, and Ln-based nanoparticles which were synthesized from novel metal alkoxide, amide, and alkyl precursors. We illustrate the applications of some of these materials as imaging probes to detect signaling pathway components and cellular responses to signals (apoptosis and degranulation) in inflammatory and cancer cells.

Cell Physiological Phenomena↗

PubMed2005

Tribasic lead maleate and lead maleate: synthesis and structural and spectroscopic characterizations.

We report on the synthesis and structure of tribasic lead maleate hemihydrate ([Pb4O3]C2H2(CO2)2.(1/2)H2O, TRIMAL) and lead maleate (PbC2H2(CO2)2, PBMAL). The structure of [Pb4O3]C2H2(CO2)2.(1/2)H2O, solved ab initio from X-ray powder diffraction data, consists of infinite slabs of edge-sharing OPb4 tetrahedra, of composition [Pb4O3], running along the c axis and linked together into a three-dimensional network by tetradentate maleate anionic ligands. The structure of PbC2H2(CO2)2, solved from single crystal diffraction data, is lamellar and contains double layers of heptacoordinated lead atoms, bonded only to the oxygen atoms of the maleate ligands. In both compounds, lead is in the oxidation state 2+ and the coordination polyhedra around the Pb2+ exhibit a hemidirected geometry and are strongly distorted as a result of the lone pair of electrons. The absence of protons on the acidic portion of the maleate moieties was confirmed by Raman spectroscopy and by 1H MAS and 1H-13C CP MAS NMR experiments. The two compounds were further characterized using chemical and thermogravimetric analyses.

Journal Article↗

PubMed2005

Speciation in the AlCl3/SO2Cl2 catholyte system.

The fundamental chemical behavior of the AlCl(3)/SO(2)Cl(2) catholyte system was investigated using (27)Al NMR spectroscopy, Raman spectroscopy, and single-crystal X-ray diffraction. Three major Al-containing species were found to be present in this catholyte system, where the ratio of each was dependent upon aging time, concentration, and/or storage temperature. The first species was identified as [Cl(2)Al(mu-Cl)](2) in equilibrium with AlCl(3). The second species results from the decomposition of SO(2)Cl(2) which forms Cl(2)(g) and SO(2)(g). The SO(2)(g) is readily consumed in the presence of AlCl(3) to form the crystallographically characterized species [Cl(2)Al(mu-O(2)SCl)](2) (1). For 1, each Al is tetrahedrally (T(d)) bound by two terminal Cl and two mu-O ligands whereas, the S is three-coordinated by two mu-O ligands and one terminal Cl. The third molecular species also has T(d)-coordinated Al metal centers but with increased oxygen coordination. Over time it was noted that a precipitate formed from the catholyte solutions. Raman spectroscopic studies show that this gel or precipitate has a component that was consistent with thionyl chloride. We have proposed a polymerization scheme that accounts for the precipitate formation. Further NMR studies indicate that the precipitate is in equilibrium with the solution.

Journal Article↗

PubMed2005

Cadmium amido alkoxide and alkoxide precursors for the synthesis of nanocrystalline CdE (E = S, Se, Te).

The synthesis and characterization of a family of alternative precursors for the production of CdE nanoparticles (E = S, Se, and Te) is reported. The reaction of Cd(NR2)2 where NR2 = N(SiMe3)2 with n HOR led to the isolation of the following: n = 1 [Cd(mu-OCH2CMe3)(NR2)(py)]2 (1, py = pyridine), Cd[(mu-OC6H3(Me)(2)-2,6)2Cd(NR2)(py)]2 (2), [Cd(mu-OC6H3(CHMe2)(2)-2,6)(NR2)(py)]2 (3), [Cd(mu-OC6H3(CMe3)(2)-2,6)(NR2)(py)]2 (4), [Cd(mu-OC6H2(NH2)(3)-2,4,6)(NR2)(py)]2 (5), and n = 2 [Cd(mu-OC6H3(Me)(2)-2,6)(OC6H3(Me)(2)-2,6)(py)2]2 (6), and [Cd(mu-OC6H3(CMe3)(2)-2,6)(OC6H3(CMe3)(2)-2,6)(THF)]2 (7). For all but 2, the X-ray crystal structures were solved as discrete dinuclear units bridged by alkoxide ligands and either terminal -NR2 or -OR ligands depending on the stoichiometry of the initial reaction. For 2, a trinuclear species was isolated using four mu-OR and two terminal -NR2 ligands. The coordination of the Cd metal center varied from 3 to 5 where the higher coordination numbers were achieved by binding Lewis basic solvents for the less sterically demanding ligands. These complexes were further characterized in solution by 1H, 13C, and 113Cd NMR along with solid-state 113Cd NMR spectroscopy. The utility of these complexes as "alternative precursors" for the controlled preparation of nanocrystalline CdS, CdSe, and CdTe was explored. To synthesize CdE nanocrystals, select species from this family of compounds were individually heated in a coordinating solvent (trioctylphosphine oxide) and then injected with the appropriate chalcogenide stock solution. Transmission electron spectroscopy and UV-vis spectroscopy were used to characterize the resultant particles.

Journal Article↗

PubMed2005

Synthesis and characterization of a family of structurally characterized dysprosium alkoxides for improved fatigue-resistance characteristics of PDyZT thin films.

Using either an ammoniacal route, the reaction between DyCl3, Na0, and HOR in liquid ammonia, or preferentially reacting Dy(N(SiMe3)2)3 with HOR in a solvent, we isolated a family of dysprosium alkoxides as [Dy(mu-ONep)2(ONep)]4 (1), (ONep)2Dy[(mu3-ONep)(mu-ONep)Dy(ONep)(THF)]2(mu-ONep) (2), (ONep)2Dy[(mu3-ONep)(mu-ONep)Dy(ONep)(py)]2(mu-ONep) (3), [Dy3(mu3-OBut)2(mu-OBut3(OBut)4(HOBut)2] (4), [Dy3(mu3-OBut)2(mu-OBut)3(OBut)4(THF)2] (5), [Dy3(mu3-OBut)2(mu-OBut)3(OBut)4(py)2] (6), (DMP)Dy(mu-DMP)4[Dy(DMP)2(NH3)]2 (7), [Dy(eta6-DMP)(DMP)2]2 (8), Dy(DMP)3(THF)3 (9), Dy(DMP)3(py)3 (10), Dy(DIP)3(NH3)2 (11), [Dy(eta6-DIP)(DIP)2]2 (12), Dy(DIP)3(THF)2 (13), Dy(DIP)3(py)3 (14), Dy(DBP)3(NH3) (15), Dy(DBP)3 (16), Dy(DBP)3(THF) (17), Dy(DBP)3(py)2 (18), [Dy(mu-TPS)(TPS2]2 (19), Dy(TPS)3(THF)3 (20), and Dy(TPS)3(py)3 (21), where ONep = OCH2CMe3, OBut) = OCMe3, DMP = OC6H3(Me)(2)-2,6, DIP = OC6H3(CHMe2)(2)-2,6, DBP = OC6H3(CMe3)(2)-2,6, TPS = OSi(C6H5)3, tol = toluene, THF = tetrahydrofuran, and py = pyridine. We were not able to obtain X-ray quality crystals of compounds 2, 8, and 9. The structures observed and data collected for the Dy compounds are consistent with those reported for its other congeners. A number of these precursors were used as Dy dopants in Pb(Zr0.3Ti0.7)O3 (PZT 30/70) thin films, with compound 12 yielding the highest-quality films. The resulting Pb0.94Dy0.04(Zr0.3Ti0.7)O3 [PDyZT (4/30/70)] had similar properties to PZT (30/70), but showed substantial resistance to polarization reversal fatigue.

Journal Article↗

PubMed2005

Anhydrous solution synthesis of germanium nanocrystals from the germanium(II) precursor Ge[N(SiMe3)2]2.

A convenient, simple, single-source solution synthesis of Ge nanocrystals via thermal reduction of Ge(II) precursor Ge[N(SiMe3)2]2 in a non-coordinating solvent at 300 degrees C and 1 atm Ar is described.

Germanium↗

PubMed2004

Synthesis and characterization of a series of rubidium alkoxides and rubidium-titanium double alkoxides.

This report investigates the structural aspects of the products isolated from the reactions of a series of titanium alkoxides [[Ti(OR)4]n n = 2, OR = OCH2C(CH3)3 (ONep) (1); n = 1, OC6H3(CH3)2-2,6 (DMP) (2)] with rubidium alkoxides [[Rb(OR)]infinity where OR = (ONep) (3), (DMP) (4), and OC6H3(CH(CH3)2)2-2,6 (DIP) (5)]. The resultant double alkoxides were determined by single crystal X-ray diffraction to be [Rb(mu-ONep)4(py)Ti(ONep)]2 (6), [Rb(mu-DMP)Ti(DMP)4]infinity (7), and [Rb(mu-DMP)2(mu-ONep)2Ti(ONep)]infinity (8). Compound 1 is the previously reported dinculear species with trigonal bipyramidal Ti metal centers whereas compound 2 is a monomer with a tetrahedral Ti center. Suitable X-ray quality crystals of 3 were not isolated. Compounds 4 and 5 demonstrate extended polymeric networks with Rb coordination ranging from two to five utilizing terminal mu- and mu3-OR ligands and pi-interactions of neighboring OAr ligands. The double alkoxide 6 revealed a simple tetranuclear structure with mu-ONep acting as the bridge, terminal ONep ligands on the Ti, and one terminal py on the Rb. For 7 and 8, the pi-interaction facilitated the formation of extended polymeric systems. All complexes were further characterized by FT-IR and multinuclear NMR spectroscopy.

Journal Article↗

PubMed2004

Membrane receptor mapping: the membrane topography of Fc(epsilon)RI signaling.

Ligand binding to membrane receptors initiates cascades of biochemical events leading to physiological responses. Hundreds of proteins and lipids are implicated in signaling networks and programs in genomics and proteomics are continuously adding new components to the signaling "parts lists". Here, we generate high resolution maps of signaling networks using cytoplasmic face-up membrane sheets that can be labeled with immunogold probes (3-10 nm) and imaged in the transmission electron microscope. Our model system is the mast cell and we focus on mapping the topography of the high affinity IgE receptor, Fc(epsilon)RI, its associated tyrosine kinases, Lyn and Syk, and the signaling proteins that propagate signals from these kinases. Crosslinked receptors and their signaling partners segregate during signaling to multiple, dynamic membrane domains, including a transient Fc(epsilon)RI-Lyn domain and at least two other distinct domains, one characterized by the presence of receptor, Syk and multiple signaling proteins, but not Lyn (primary signaling domains), and one characterized by the presence of LAT and PLCgamma1 but not receptor (secondary signaling domains). PI 3-kinase associates with both primary and secondary signaling domains and may help to recruit specific signaling proteins through the local remodeling of inositol phospholipids. The lipid raft markers, GM1 and Thy-1, fail to localize in native membrane sheets either with each other or with signaling domains. We introduce new probes to localize multiple signaling molecules on the same membrane sheet and new computational tools to capture and analyze their topographical relationships. In the future, we expect that high resolution maps of signaling networks will be integrated with chemical kinetic analyses, with cell fractionation data and with a range of real-time fluorescence measurements, into mathematical models with power to predict mechanisms that regulate the efficiency, specificity, amplitude and duration of signaling pathways.

Animals↗

PubMed2003

Structural variations of potassium aryloxides.

A series of potassium aryloxides (KOAr) were isolated from the reaction of a potassium amide (KN(SiMe(3))(2)) and the desired substituted phenoxide (oMP, 2-methyl; oPP, 2-iso-propyl; oBP, 2-tert-butyl; DMP, 2,6-di-methyl; DIP, 2,6-di-iso-propyl; DBP, 2,6-di-tert-butyl) in tetrahydrofuran (THF) or pyridine (py) as the following: [([K(mu(4)-oMP)(THF)][K(mu(3)-oMP)])(5)]( infinity ) (1), [[K(6)(eta(6),mu(3)-oMP)(4)(eta(6),mu(4)-oMP)(2)(py)(4)].[K(6)(eta(6),mu(3)-oMP)(6)(eta(6)-py)(4)]]( infinity ) (2), [K(mu(3)-oPP)](4)(THF)(3) (3), [K(4)(eta(6),mu(3)-oPP)(2)(mu(3)-oPP)(2)(py)(3)]( infinity ) (4), [K(mu(3)-oBP)(THF)](6) (5), [K(6)(eta(6),mu(3)-oBP)(2)(mu(3)-oBP)(4)(py)(4)]( infinity ) (6), [K(3)(eta(6),mu(3)-DMP)(2)(mu-DMP)(THF)]( infinity ) (7), [[K(eta(6),mu-DMP)(py)](2)]( infinity ) (8), [K(eta(6),mu-DIP)]( infinity ) (9), [K(eta(6),mu-DBP)]( infinity ) (10). Further exploration of the aryl interactions led to the investigation of the diphenylethoxide (DPE) derivative which was isolated as [K(mu(3)-DPE)(THF)](4) (11) or [K(mu(3)-DPE)(py)](4).py(2) (12) depending on the solvent used. In general, the less sterically demanding ligands (oMP, oPP, oBP, and DMP) were solvated polymeric species; however, increasing the steric bulk (DIP and DBP) led to unsolvated polymers and not discrete molecules. For most of this novel family of compounds, the K atoms were pi-bound to the aryl rings of the neighboring phenoxide derivatives to fill their coordination sites. The synthesss and characterization of these compounds are described in detail.

Journal Article↗

PubMed2002

Chemistry of a novel family of tridentate alkoxy tin(II) clusters.

The chemical interconversions observed for a novel family of trihydroxymethyl ethane (THME-H(3)) ligated Sn(II) compounds have been determined using single-crystal X-ray and (119)Sn NMR experiments. (mu-THME)(2)Sn(3) (1) was isolated from the reaction of 3 equiv of [Sn(NR(2))(2)](2) (R = SiMe(3)) with 4 equiv of THME as a unique trinuclear species capped above and below the plane of Sn atoms by two THME ligands. Upon reaction with "Sn(NR(2))(2)", compound 1 rearranged to yield another novel molecule [(mu-THME)Sn(2)(NR(2))](2) (2). Compound 2 could also be formed directly from the stoichiometric mixture of THME-H(3) and [Sn(NR(2))(2)](2). Further studies revealed that 1 would also rearrange in the presence of Sn(OR)(2) to form [(mu-THME)Sn(2)(mu-OR)](2) [OR = OMe (3), OCH(2)Me (4), OCH(2)CH(Me)CH(2)CH(3) (5), OCH(2)CMe(3) (6, ONep), OC(6)H(5) (7, not structurally characterized), OC(6)H(4)Me-3 (8), OC(6)H(4)Me-2 (9), OC(6)H(3)(Me)(2)-2,6 (10), OC(6)H(3)(CHMe(2))(2)-2,6 (11). Additionally, 3-11 could by synthesized from the reaction of 2 and the appropriate H-OR. (119)Sn solution NMR studies of 2-11, in THF-d(8), indicate that an equilibrium between the parent complex and its disassociation products (1 and the free parent Sn alkoxy or amide precursor) exists at room temperature. This is a likely reason behind the ease of interconversion observed for 1. The generality of this exchange was further verified through the reaction of 1 with [Ti(mu-ONep)(ONep)(3)](2), which led to the isolation of (mu-ONep)(2)Sn(3)(mu-THME)(2)Ti(ONep)(2) (12). For 12, the solid-state structure was maintained in solution with no indication of an equilibrium.

Journal Article↗

PubMed2002

Hydrolysis of tin(II) neo-pentoxide: syntheses, characterization, and X-ray structures of [Sn(ONep)(2)](infinity), Sn(5)(mu(3)-O)(2)(mu-ONep)(6), and Sn(6)(mu(3)-O)(4)(mu-ONep)(4) where ONep = OCH(2)CMe(3).

The reaction of [Sn(NMe(2))(2)](2) (1) with 4 equiv of HOCH(2)CMe(3) (HONep) leads to the isolation of [Sn(ONep)(2)](infinity) (2). Each Sn atom is four coordinated with mu-ONep ligands bridging the metal centers; however, if the free electrons of the Sn(II) metal center are considered, each Sn center adopts a distorted trigonal bipyramidal (TBP) geometry. Through (119)Sn NMR experiments, the polymeric compound 2 was found to be disrupted into smaller oligomers in solution. Titration of 2 with H(2)O led to the identification of two unique hydrolysis products characterized by single-crystal X-ray diffraction as Sn(5)(mu(3)-O)(2)(mu-ONep)(6) (3) and Sn(6)(mu(3)-O)(4)(mu-ONep)(4) (4). Compound 3 consists of an asymmetrical molecule that has five Sn atoms arranged in a square-based pyramidal geometry linked by four basal mu-ONep ligands, two facial mu(3)-O, and two facial mu-ONep ligands. Compound 4 was solved in a novel octahedral arrangement of six Sn cations with an asymmetric arrangement of mu(3)-O and mu-ONep ligands that yields two square base pyramidal and four pyramidal coordinated Sn cations. These compounds were further identified by multinuclear ((1)H, (13)C, (17)O, and (119)Sn) solid-state MAS and high resolution, solution NMR experiments. Because of the complexity of the compounds and the accessibility of the various nuclei, 2D NMR experiments were also undertaken to elucidate the solution behavior of these compounds. On the basis of these studies, it was determined that while the central core of the solid-state structures of 3 and 4 is retained, dynamic ligand exchange leads to more symmetrical molecules in solution. Novel products 3 and 4 lend structural insight into the stepwise hydrolysis of Sn(II) alkoxides.

Journal Article↗

PubMed2002

From clusters to ionic complexes: structurally characterized thallium titanium double alkoxides.

A series of sterically varied titanium alkoxides [[Ti(OR)(4)](n)(), n = 4, OR = OCH(2)CH(3) (OEt); n = 1, OCH(CH(3))(2) (OPr(i)); n = 2, OCH(2)C(CH(3))(3) (ONep); n = 1, OC(6)H(3)(CH(3))(2)-2,6 (DMP)] were reacted with a series of thallium alkoxides [[Tl(OR)](x) (x = 4, OR = OEt, ONep; n = infinity, DMP)]. The resultant products of the [Tl(mu(3)-OEt)](4)-modified [Ti(OR)(4)](n)() (OR = OEt, OPr(i), ONep) were found by X-ray analysis to be Tl(4)Ti(2)(mu-O)(mu(3)-OEt)(8)(OEt)(2) (1), Tl(4)Ti(2)(mu-O)(mu(3)-OPr(i))(5)(mu(3)-OEt)(3)(OEt)(2) (2), and TlTi(2)(mu(3)-OEt)(2)(mu-OEt)(mu-ONep)(2)(ONep)(4) (3), respectively. The reaction of [Tl(mu(3)-OEt)](4), 12HOEt, and 4[Ti(mu-ONep)ONep)(3)](2) to generate 3 in a higher yield resulted in the isolation of TlTi(2)(mu(3)-OEt)(mu(3)-ONep)(mu-OEt)(mu-ONep)(2)(ONep)(4) (4). Compounds 1 and 2 possess an octahedral (Oh) arrangement of two Ti and four Tl metal atoms around a mu-O central oxide atom (the Tl-O distance is too long to be considered a bond). For both compounds, each Ti atom adopts a distorted Oh geometry with one terminal OEt ligand. The Tl atoms are formally 4-coordinated, adopting a distorted pyramidal geometry using four mu(3)-OR (OR = OEt or OPr(i)) ligands to complete their coordination sphere. The Tl atoms reside approximately 1.4 A below the basal plane of oxygens. In contrast to these structures, both 3 and 4 utilize ONep ligands and display reduced oligomerization yielding trinuclear complexes without oxo formation. The two Ti cations are Oh, and the single Tl cation is in a formal distorted pyramidal (PYD) arrangement. If the lone pair of the Tl cations are considered in the geometry, each Tl adopts a square base pyramidal geometry. Two terminal ONep ligands are bound to each Ti with the remainder of the molecule consisting of mu(3)- and mu-ONep ligands. The reaction of [Tl(mu(3)-ONep)](4) with two equivalents of [Ti(mu-ONep)(ONep)(3)](2) also led to the isolation of the homoleptic trinuclear complex TlTi(2)(mu(3)-ONep)(2)(mu-ONep)(3)(ONep)(4) (5) which is analogous in structure to the mixed ligand species of 3 and 4. Each Ti is Oh coordinated with six ONep ligands, and the single Tl is PYD bound by ONep ligands. A further increase in the steric bulk of the pendant ligands, using [Tl(mu-DMP)](infinity) and [Ti(mu-ONep)(ONep)(3)](2), resulted in a further decrease in the nuclearity yielding the dinuclear species TlTi(mu-DMP)(mu-ONep)(DMP)(ONep)(2) (6). For 6, the two metals are bound by a mu-ONep and a mu-DMP ligand. The Tl metal center was solved in a bent geometry while the Ti adopted a distorted trigonal bipyramidal (TBP) geometry using three ONep and two DMP ligands to fill its coordination sphere. Further increasing the steric bulk of the ancillary ligands using Ti(DMP)(4) and [Tl(mu-DMP)](infinity) led to the formation of [Tl(+)][(-)(eta(2-3)-DMP)Ti(DMP)(4)] (7). The Ti metal center is in a TBP geometry, and the "naked" Tl cation resides unencumbered by solvent molecules but was found to have a strong pi-interaction with four DMP ligands of neighboring Ti(DMP)(5)(-) anions. For this novel set of compounds, (205)Tl NMR spectroscopy was used to investigate the solution behavior of these compounds. Multiple (205)Tl resonances were observed for the solution spectra of the crystalline material of 1-6, and a broad singlet was observed for 7. The large number of minor resonances noted for these compounds was attributed to sensitivity of the Tl cation based on small variations due to ligand rearrangement. However, the major resonance noted in the (205)Tl NMR solution spectra of 1-7 are in agreement with their respective solid-state structures.

Journal Article↗