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PubMed1991

[Determining the level of yttrium oxide-coated silicon nitride in the air of the work area].

To measure the concentrations of yttrium-oxide-coated small-dispersed silicon nitride plasma powder, the air was aspirated at the amount of 10-15 litres per min through the AFA-XP filter. The filter was limed in a platinum crucible, the residuum being alloyed with Na2CO3, Na2B4O7, NaNO3 in ratio 10:5:1. The alloy was transferred into solution in which the silicon content was assessed through reactions with ammonium molybdate, and yttrium--through reactions with arsenaso III. The sensibility rate for silicon was at 0.07 mg/m3.

Air Pollutants, Occupational↗
PubMed1989

Intracavitary therapy with radioactive yttrium: results of animal experiments.

The distribution of radioactive yttrium was studied in guinea-pigs. The injection of 1,5 mci of radioactive yttrium leads to a mean surface dose of 20 Gy which can be obtained within 5 days. An extrapolation of these findings to the peritoneal surface of human beings should lead to a corresponding dose of 64 mci.

Animals↗
PubMed1989

[Intracystic instillation of yttrium 90 silicate colloid in cystic craniopharyngioma].

The authors evaluate the intracavital treatment with 90 Yttrium silicate colloid given in 31 occasion in 26 patients of cystic craniopharyngioma. The method has been applied since 1975 in the National Institute of Neurosurgery Budapest, using practically the same method as described by Backlund et al. (1972). Although the intracavital treatment was only one among several applied forms of treatment (resection, aspiration, shunting etc.) the effectiveness of the internal irradiation is obvious. The main effect is shrinkage of the cyst. At the 26 patients there was an average of more than 70% volume decrease of the cysts. In 5 cases the cysts totally disappeared and only on two occasions the volume has remained unchanged. Neuroophtalmological data: Preoperatively visual field defects or an impairment of visual activity have been observed in 24 out of the 26 patients studied. After the 90-Yttrium treatment the ophtalmological state of the patients improved 4, worsened in 2 cases. There was no change in 18 cases. The neuroophtalmological prognosis was good only when a relatively intact optic disc was seen; when the disc was atrophic the visual deterioration proved to be irreversible. Pathologically, the fibrotic tissue is responsible for the shrinkage of the cyst.

Administration, Topical↗
PubMed1983

Neodymium-yttrium aluminium garnet laser destruction of nonsensitized and hematoporphyrin derivative-sensitized tumors.

The injection of hematoporphyrin derivative (5 mg/kg i.v.) followed 24 hr later by a neodymium-yttrium aluminium garnet laser irradiation shows the destruction of CX1 tumors grafted on nude mice. This acidophilic necrosis occurred with a significantly increased frequency in tumors treated by hematoporphyrin derivative injection and irradiated with the neodymium-yttrium aluminium garnet laser as compared with noninjected but irradiated tumors or with injected tumors irradiated with sunlight. On the basis of our data, it seems difficult to maintain the hypothesis of singlet oxygen production as the only mechanism of the phenomenon. Further studies will be necessary to explain the necrosis that we observed.

Adenocarcinoma↗
PubMed1997

Yttrium-90 radiochemical synovectomy in chronic knee synovitis: a one year retrospective review of 133 treatment interventions.

OBJECTIVE: To determine treatment success rates and factors predicting successful outcome using yttrium-90 intraarticular injections for chronic knee synovitis refractory to other treatments. METHODS: A retrospective one year review of 133 treatment interventions with yttrium-90 (Y-90) with response recorded at 3, 6, 9, and 12 mo after injection. RESULTS: An excellent, good, or fair response (a treatment benefit) as evaluated by objective (degree of joint effusion, joint tenderness, range of motion) and subjective (visual analog scale, degree of pain) assessments occurred in 81, 82, 80, and 75% of joints at 3, 6, 9, and 12 mo, respectively. When only excellent and good responses were considered successful treatment then 49, 48, 57, and 46% had successful treatment at 3, 6, 9, and 12 mo, respectively. 8 of 15 joints (53%) reinjected after primary treatment failure or relapse showed a beneficial response. Patients treated successfully were more likely to have a normal radiographic appearance rather than one showing destructive changes (78 vs 54% treatment success; p < 0.05); to have localized disease or systemic disease in remission, rather than active systemic disease (66 vs 30% treatment success; p < 0.001); and shorter duration of joint disease (6.9 vs 10.2 years; p < 0.05). CONCLUSION: Y-90 synovectomy successfully treats patients with chronic knee synovitis refractory to other therapies. Primary treatment failures or relapses may be successfully treated by reinjection. Patients with less destructive radiographic changes, shorter duration of joint disease, and localized disease tend to respond more favorably.

Adolescent↗
PubMed1997

Radioassay of yttrium-90 radiation using the radionuclide dose calibrator.

UNLABELLED: Yttrium-90 is used in radioimmunotherapy because of its favorable physical half-life and energetic pure beta emissions. However, it is often necessary to standardize 90Y sources to establish a dose calibrator dial setting for accurate calibration of clinical doses of 90Y preparations. METHODS: A solution of 90YCl3 containing 2.81 kBq/ml (by supplier's calibration) was prepared by serial dilution In 0.05 M HCl. Ten 100-microliters aliquots of this solution were counted in a Packard liquid scintillation analyzer; the mean radioactivity in becquerels was determined and used to evaluate dial settings 48 x 10,775 x 70 and 775 x 100 on a radionuclide dose calibrator for 90Y measurements. The dose calibrator response was also studied on 90Y sources at varying solution volumes in plastic and glass containers. RESULTS: Calibrator readings of 90Y sources in glass and plastic vials and plastic syringes were accurate at either dial setting 48 x 10 (commonly used by many 90Y laboratories) or 775 x 70. Measurements of 1.15 and 3.03 GBq (31 and 82 mCi, respectively) calibrated 90Y sources in either vial were -3.0 and +4.3%, respectively, at dial-setting 775 x 70 and -4.0 and +9.0% at 48 x 10. Yttrium-90 sources in plastic syringes gave higher readings than those in glass vials, therefore, requiring a container correction factor for accurate dose assay. Measurements of 90YCl3 shipments from four suppliers over a 3-yr period demonstrated concurring calibration measurements at both 775 x 70 and 48 x 10 settings for shipments from all suppliers. The dose calibrator response to 90Y radiation was linear within a 1-333 kBq range in a constant sample volume of 580 microliters. CONCLUSION: This work demonstrates the validity of using the 48 x 10 dial-factor combination on the standard radionuclide dose calibrator for calibration of 90Y radiopharmaceuticals.

Calibration↗
PubMed1998

Optimized conditions for chelation of yttrium-90-DOTA immunoconjugates.

UNLABELLED: Radioimmunotherapy (RIT) with 90Y-labeled immunoconjugates has shown promise in clinical trials. The macrocyclic chelating agent 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA) binds 90Y with extraordinary stability, minimizing the toxicity of 90Y-DOTA immunoconjugates arising from loss of 90Y to bone. However, reported 90Y-DOTA immunoconjugate product yields have been typically only < or =50%. Improved yields are needed for RIT with 90Y-DOTA immunoconjugates to be practical. METHODS: (S) 2-[p-(bromoacetamido)benzyl]-DOTA (BAD) was conjugated to the monoclonal antibody Lym-1 via 2-iminothiolane (2IT). The immunoconjugate product, 2IT-BAD-Lym-1, was labeled in excess yttrium in various buffers over a range of concentrations and pH. Kinetic studies were performed in selected buffers to estimate radiolabeling reaction times under prospective radiopharmacy labeling conditions. The effect of temperature on reaction kinetics was examined. Optimal radiolabeling conditions were identified and used in eight radiolabeling experiments with 2IT-BAD-Lym-1 and a second immunoconjugate, DOTA-peptide-chimeric L6, with 248-492 MBq (6.7-13.3 mCi) of 90Y. RESULTS: Ammonium acetate buffer (0.5 M) was associated with the highest uptake of yttrium. On the basis of kinetic data, the time required to chelate 94% of 90Y (four half-times) under prospective radiopharmacy labeling conditions in 0.5 M ammonium acetate was 17-148 min at pH 6.5, but it was only 1-10 min at pH 7.5. Raising the reaction temperature from 25 degrees C to 37 degrees C markedly increased the chelation rate. Optimal radiolabeling conditions were identified as: 30-min reaction time, 0.5 M ammonium acetate buffer, pH 7-7.5 and 37 degrees C. In eight labeling experiments under optimal conditions, a mean product yield (+/- s.d.) of 91%+/-8% was achieved, comparable to iodination yields. The specific activity of final products was 74-130 MBq (2.0-3.5 mCi) of 90Y per mg of monoclonal antibody. The immunoreactivity of 90Y-labeled immunoconjugates was 100%+/-11%. CONCLUSION: The optimization of 90Y-DOTA chelation conditions represents an important advance in 90Y RIT because it facilitates the dependable and cost-effective preparation of 90Y-DOTA pharmaceuticals.

Buffers↗
PubMed2004

Yttrium and lanthanide diphosphanylamides: syntheses and structures of complexes with one [(Ph2P)2N]- ligand in the coordination sphere.

Treatment of the recently reported potassium salt [K(thf)(n)][N(PPh(2))(2)] (n=1.25, 1.5) with anhydrous yttrium or lanthanide trichlorides in THF leads after crystallization from THF/n-pentane (1:2) to the monosubstituted diphosphanylamide complexes [LnCl(2)[(Ph(2)P)(2)N](thf)(3)] (Ln=Y, Sm, Er, Yb). The single-crystal X-ray structures of these complexes show that the metal atoms are surrounded by seven ligands in a distorted pentagonal bipyramidal arrangement, in which the chlorine atoms are located in the apical positions. The diphosphanylamide ligand is always eta(2)-coordinated through the nitrogen atom and one phosphorus atom. Further reaction of [SmCl(2)[(Ph(2)P)(2)N](thf)(3)] with K(2)C(8)H(8) or reaction of [LnI(eta(8)-C(8)H(8))(thf)(3)] with [K(thf)(n)][N(PPh(2))(2)] in THF gives the corresponding cyclooctatetraene complexes [Ln[(Ph(2)P)(2)N](eta(8)-C(8)H(8))(thf)(2)] (Ln=La, Sm). The single crystals of these compounds contain enantiomerically pure complexes. Both compounds adopt a four-legged piano-stool conformation in the solid state. The structures of the A and the C enantiomers were established by single-crystal X-ray diffraction. The more soluble bistrimethylsilyl cyclooctatetraene complex [Y[(Ph(2)P)(2)N](eta(8)-1,4-(Me(3)Si)(2)C(8)H(6))(thf)(2)] was obtained by transmetallation of Li(2)[1,4-(Me(3)Si)(2)C(8)H(6)] with anhydrous yttrium trichloride in THF followed by the addition of one equivalent of [K(thf)(n)][N(PPh(2))(2)]. The (89)Y NMR signal of the complex is split up into a triplet, supporting other observations that the phosphorus atoms are chemically equivalent in solution and, thus, dynamic behavior of the ligand in solution can be anticipated.

Journal Article↗
PubMed2006

The effect of the beta-emitting yttrium-90 citrate on the dose-response of dicentric chromosomes in human lymphocytes: a basis for biological dosimetry after radiosynoviorthesis.

The production of dicentric chromosomes in human lymphocytes by beta-particles of yttrium-90 (Y-90) was studied in vitro to provide a basis of biological dosimetry after radiosynoviorthesis (RSO) of persistent synovitis by intra-articular administration of yttrium-90 citrate colloid. Since the injected colloid may leak into the lymphatic drainage exposing other parts of the body to radiation, the measurement of biological damage induced by beta-particles of Y-90 is important for the assessment of radiation risk to the patients. A linear dose-response relationship (alpha = 0.0229 +/- 0.0028 dicentric chromosomes per cell per gray) was found over the dose range of 0.2176-2.176 Gy. The absorbed doses were calculated for exposure of blood samples to Y-90 activities from 40 to 400 kBq using both Monte Carlo simulation and an analytical model. The maximum low-dose RBE, the RBE(M) which is equivalent to the ratio of the alpha coefficients of the dose-response curves, is well in line with published results obtained earlier for irradiation of blood of the same donor with heavily filtered 220 kV X-rays (3.35 mm copper), but half of the RBE(M) relative to weakly filtered 220 kV X-rays. Therefore, it can be concluded that for estimating an absorbed dose during RSO by the technique of biological dosimetry, in vitro and in vivo data for the same radiation quality are necessary.

Beta Particles↗
PubMed1991

Neodymium:yttrium-aluminum garnet laser-assisted pulmonary resections.

The neodymium:yttrium-aluminum garnet laser is a new approach to limited pulmonary resection. It avoids distortion of surrounding pulmonary tissue and potential pleural space problems, which can occur with mechanical stapler resections. We have recently used this laser to manage 39 pulmonary lesions in 20 patients. There were no major postoperative complications, and air leak after resection was minimal. Neodymium:yttrium-aluminum garnet laser excision is a useful method that may have an advantage over mechanical stapling techniques for the limited resection of many pulmonary lesions.

Female↗
PubMed1985

Histologic study of normal rat brain tissue after neodymium-yttrium aluminum garnet laser irradiation. I. Cerebral hemisphere.

We report a histologic study of normal rat brain tissue after neodymium-yttrium aluminum garnet laser irradiation. Morphological changes occurred at a maximum depth of 5 mm after 60-W, 1-second exposure, at a 2-mm distance between the optical fiber tip and the brain surface. Polymorphonuclear leukocyte infiltration into the irradiated area was observed 48 hours after irradiation. After 72 hours, macrophages and fibroblasts appeared; their number increased thereafter. At 1 month, tissue defects attributable to neodymium-yttrium aluminum garnet laser irradiation were small. Gliotic changes were rarely seen. We conclude that 60-W irradiation is harmful to young rats but not to adult rats.

Animals↗
PubMed1998

Treatment of biliary calculi using holmium: yttrium aluminum garnet laser.

BACKGROUND: The holmium: yttrium aluminum garnet laser (Ho: YAG) has been shown to be effective and safe for the treatment of urinary calculi. Its effectiveness for the treatment of biliary calculi was investigated. METHODS: Endoscopic Ho: YAG lithotripsy of biliary stones was performed 7 times in 4 patients. Two patients had biliary duct calculi, and the other two patients had gall bladder calculi. All patients had multiple calculi that ranged in size from 4 mm to 5 cm. All procedures were performed percutaneously under intravenous sedation and local anesthesia. Rigid and flexible endoscopes were used to access the biliary calculi. Postoperative cholangiograms were performed on all patients. RESULTS: All calculi were successfully fragmented with the Ho: YAG laser. The most common settings on the laser were 1.0 J and 10 Hz. Average total laser energy used was 12.24 kJ. Two patients required multiple procedures for the resolution of the biliary calculi. No vascular or biliary injuries were encountered. Three patients were free of biliary calculi on their postoperative cholangiogram. One patient with multiple gallbladder stones refused further treatment after two percutaneous procedures. CONCLUSION: The holmium: yttrium aluminum garnet laser can be used safely and effectively in the endoscopic treatment of biliary calculi. This treatment maybe a suitable option in patients who are not candidates for more invasive procedures.

Adult↗
PubMed1999

Q-switched neodymium:yttrium-aluminum-garnet laser treatment of lentigo maligna.

Lentigo maligna is a premalignant lesion of atypical melanocytes that typically arises on the head and neck of elderly patients. It is considered a melanoma in situ with a significant risk for transformation to invasive lentigo maligna melanoma. Surgery is the preferred method of treatment; however, because of the advanced age of the typical patient with lentigo maligna, the frequency of complicating medical problems, and the cosmetic or functional aspects of treatment, surgical excision is not always feasible. The purpose of this pilot study was to evaluate the efficacy and safety of Q-switched neodymium:yttrium-aluminum-garnet laser treatment of lentigo maligna. Eight patients were treated with 532 and/or 1064 nm wavelengths from the laser. All patients showed a response to laser therapy, and 2 patients treated with 1 treatment from each wavelength had complete eradication of the LM, with no evidence of recurrence in 42 months. Further study is warranted, but Q-switched neodymium:yttrium-aluminum-garnet laser is a promising alternative treatment for lentigo maligna.

Aged↗
PubMed1995

Neodymium:yttrium-aluminum-garnet laser fusion of endarterectomy flaps.

PURPOSE: This study evaluated the efficacy of neodymium:yttrium-aluminum-garnet laser welding of flaps in canine arteries and in securing the distal flap during human carotid endarterectomy. METHODS: Endarterectomy flaps were created in both common carotid and both common femoral arteries in 12 dogs. The flaps were repaired with either the neodymium:yttrium-aluminum-garnet laser or with 6-0 polypropylene sutures. The arteries were removed after duplex scanning at either 7 or 28 days. Eighteen high carotid endarterectomy flaps in 16 patients have been subsequently secured with the laser welding technique. RESULTS: Laser repairs (125 +/- 19 joule) of the canine arteries were completed more quickly than suture repairs (mean 25 seconds vs 135 seconds, respectively; p < 0.04). Duplex ultrasonography revealed no discernable differences between the two groups of arteries. Arteries studied at 7 days revealed three microscopic flaps (two suture, one laser), more subintimal fibroblastic proliferation in suture than laser-repaired carotid arteries (3: 1, p = 0.0530), and similar amounts of inflammation in suture- and laser-repaired arteries. Arteries studied at 28 days revealed one microscopic intimal flap (suture-repaired); equal fibroblastic and inflammatory responses in suture- and laser-repaired vessels; and no evidence of laser thermal injury. Eighteen carotid endarterectomy flaps have been successfully fused with no immediate or long-term complications in 16 patients (follow-up of 0 to 24 months). CONCLUSION: Laser fusion appears to be a safe and effective method for securing distal carotid endarterectomy flaps.

Animals↗
PubMed2001

Terphenyl ligand systems in lanthanide chemistry: use of the 2,6-di(1-naphthyl)phenyl ligand for the synthesis of kinetically stabilized complexes of trivalent ytterbium, thulium, and yttrium.

The molecular structures of terphenyl derivatives of trivalent ytterbium, thulium, and yttrium of general composition DnpLnCl(2)(THF)(2) [Dnp = 2,6-di(1-naphthyl)phenyl] are reported. The complexes (Ln = Yb: 1; Ln = Tm: 2; Ln = Y: 3) are synthesized by reaction of 1 equiv of DnpLi with 1 equiv of LnCl(3) (Ln = Yb, Tm, or Y) in tetrahydrofuran at room temperature in 50% yield. Attempts to prepare a Dnp scandium compound gave heterobimetallic [(THF)(3)Sc(2)OCl(5)Li(THF)](2) (4) in low yield. 1 crystallizes in the monoclinic space group C2/c. Crystal data for 1 at 203 K: a = 14.333(3) A, b = 16.353(3) A, c = 12.427(2) A, beta = 91.021(4) degrees, Z = 4, D(calcd) = 1.637 g cm(-3), R(1) = 4.44%. 2 crystallizes in the monoclinic space group C2/c. Crystal data for 2 at 203 K: a = 14.333(1) A, b = 16.374(2) A, c = 12.404(1) A, beta = 90.934(2) degrees, Z = 4, D(calcd) = 1.628 g cm(-3), R(1) = 3.00%. 3 crystallizes in the monoclinic space group C2/c. Crystal data for 3 at 203 K: a = 14.348(3) A, b = 16.476(3) A, c = 12.356(2) A, beta = 90.987(4) degrees, Z = 4, D(calcd) = 1.441 g cm(-3), R(1) = 5.62%. 4 crystallizes in the monoclinic space group P2(1)/n. Crystal data for 4 at 203 K: a = 11.0975(9) A, b = 11.0976(9) A, c = 21.3305(18) A, beta = 94.718(2) degrees, Z = 2, D(calcd) = 1.051 g cm(-3), R(1) = 3.45%. Complexes 1-3 represent examples of novel chiral (racemic) organometallic complexes of the lanthanide elements ytterbium and thulium and the group 3 element yttrium, respectively. The molecular structures of monomeric 1-3 exhibit distorted trigonal-bipyramidal coordination environments at the metal center, with the two oxygen atoms of the tetrahydrofuran ligands occupying the axial positions of a trigonal-bipyramidal coordination polyeder. The molecular structure of the scandium compound 4 shows a complex polynuclear heterobimetallic arrangement.

Journal Article↗
PubMed2002

Flexibility in the coordination chemistry of the 2,3-dimethylindolide ligand with potassium, yttrium, and samarium.

The coordination chemistry of the 2,3-dimethylindolide anion (DMI), (Me(2)C(8)H(4)N)(-), with potassium, yttrium, and samarium ions is described. In the potassium salt [K(DMI)(THF)](n), 1, prepared from Me(2)C(8)H(4)NH and KH in THF, the dimethylindole anion binds and bridges potassium ions in three different binding modes, namely eta(1), eta(3), and eta(5), to form a two-dimensional extended structure. In the dimethoxyethane (DME) adduct [K(DMI)(DME)(2)](2), 2, prepared by crystallizing a sample of 1 from DME, DMI exists as a mu-eta(1):eta(1) ligand. Compound 1 reacts with SmI(2)(THF)(4) in THF to form the distorted octahedral complex trans-(DMI)(2)Sm(THF)(4), 3, in which the dimethyindolide anions are bound in the eta(1) mode to samarium. Reaction of 2,3-dimethylindole with Y(CH(2)SiMe(3))(3)(THF)(2) afforded the amide complex (DMI)(3)Y(THF)(2), 4, in which the dimethylindolide anions are also bound in the eta(1) mode to yttrium. Compound 1 also reacts with (C(5)Me(5))(2)LnCl(2)K(THF)(2) (Ln = Sm, Y) to form unsolvated amide complexes (C(5)Me(5))(2)Ln(DMI) (Ln = Sm, 5; Y, 6), in which DMI attaches primarily through nitrogen, although the edge of the arene ring is oriented toward the metals at long distances.

Journal Article↗
PubMed2003

Coordination of 2,2'-bipyridyl and 1,10-phenanthroline to yttrium and lanthanum complexes based on a scorpionate ligand.

Reaction of yttrium and lanthanum trichloride with 1 equiv of sodium or potassium hydrotris(3,5-dimethylpyrazolyl)borate and 1 equiv of 2,2'-bipyridine gives good yields of the complexes [MCl(2)(Tp(Me2))(C(10)H(8)N(2))] (M = Y (1), La (2)). The analogous compounds with 1,10-phenanthroline, [MCl(2)(Tp(Me2))(C(12)H(8)N(2))] (M = Y (3), La (4)), have been obtained by a similar procedure. The solid-state structures of 2-4 were determined by single-crystal X-ray diffraction and revealed that the compounds are all seven-coordinate with capped octahedral geometry. In contrast, reaction of yttrium trichloride with 1 equiv of sodium hydrotris(3,5-dimethylpyrazolyl)borate in the presence of 1 equiv of neocuproine affords [YCl(3)(Tp(Me2))][Na(neoc)(3))] (5). Compounds 1 and 2 provide an entry for the synthesis of complexes containing the bipyridyl ligand in a radical anionic form or in a dianionic form. Reaction of 1 and 2 with an excess of sodium amalgam gives [Y(Tp(Me2))(bipy)(THF)(2)] (6) and [La(Tp(Me2))(2)(bipy)] (7), respectively. The structures of both compounds have been determined by X-ray crystallography. Compound 7 can be oxidized with iodine to give [La(Tp(Me2))(2)(bipy)]I (8).

Journal Article↗
PubMed1997

Synthesis and Characterization of New Alkoxotitanates of Yttrium, Barium, and Copper: Single Crystal X-ray Diffraction Structures of Cl(2)Y{Ti(2)(OPr(i))(9)}, {Ti(OPr(i))(5)}Ba{Ti(2)(OPr(i))(9)}, and ClCu{Ti(2)(OPr(i))(9)}

The synthesis and characterization of new mixed-metal alkoxides of titanium with yttrium, barium, and copper, achieved via salt elimination and acid-base reactions, is described. The metathesis reactions of KTi(2)(OPr(i))(9) with anhydrous YCl(3) (1:1 and 2:1) and CuCl(2) (1:1) afford chloro-functionalized heterobimetallic alkoxides Cl(2)Y{Ti(2)(OPr(i))(9)} (1), ClY{Ti(2)(OPr(i))(9)}(2) (2), and ClCu{Ti(2)(OPr(i))(9)} (3), respectively, in high yields. The barium-titanium derivatives [Ba{Ti(2)(OPr(i))(10)}](2) (4), {Ti(2)(OPr(i))(9)}Ba{Ti(OPr(i))(5)} (5), and Ba{Ti(2)(OPr(i))(9)}(2) (6) result from the reaction between [Ba(OPr(i))(2)](n) and Ti(OPr(i))(4) in 1:2, 1:3, and 1:4 molar ratios, respectively. All the new derivatives (1-6) have been characterized by elemental analyses, variable-temperature (1)H and (13)C NMR, infrared spectroscopy, cryoscopy, and single crystal X-ray diffraction studies for 1, 3, and 5. The crystallographic study of 1 reveals a mononuclear species where the yttrium atom, coordinated by four alkoxide oxygen atoms of the {Ti(2)(OPr(i))(9)}(-) unit and two chloride ligands, is in a pseudo-octahedral arrangement. The NMR ((1)H and (13)C) and cryoscopic data for 1 indicate that the bioctahedral {Ti(2)(OPr(i))(9)} framework, as observed in the solid state structure, is retained in solution also. The X-ray structure of copper derivative 3 exhibits a triangular heterometallic core CuTi(2)(&mgr;(2)-OPr(i))(3)(&mgr;(3)-OPr(i))(2) with chloride as a terminal ligand on copper. Each titanium bears two terminal OPr(i) groups and displays a distorted octahedral geometry whereas copper has a pseudotrigonal bipyramidal environment. The high-temperature NMR studies for the paramagnetic 3 are in agreement with Curie law behavior; the isotropic shifts indicate that the OPr(i) groups bound directly to the Cu(II) center experience a greater paramagnetic influence in comparison to OPr(i) groups attached to titanium only. Barium titanates reveal an interesting observation of structural and stoichiometry (Ba/Ti) change. The dimeric compound 4 (Ba/Ti, 1:2) reacts with 1 mol of Ti(OPr(i))(4) to offer mononuclear 5 with a Ba/Ti stoichiometry of 1:3; on further addition of 1 mol of Ti(OPr(i))(4), 5 is converted to 6 (Ba/Ti, 1:4). X-ray crystallography performed on 5 shows the molecular structure to be formed by the coordination of monoanionic {Ti(OPr(i))(5)}(-) and {Ti(2)(OPr(i))(9)}(-) units to Ba(2+) in bi- and tetradentate fashion, respectively. The coordination figure of the central atom, barium, corresponds to a trigonal prism distorted toward an octahedron. Crystal data for 1: monoclinic space group Cc, a = 21.618(14) Å, b = 9.878(5) Å, c = 19.949(13) Å, beta = 109.51(4) degrees, V = 4015(4) Å(3), Z = 4. Crystal data for 3: triclinic space group P&onemacr;, a = 10.085(2) Å, b = 10.210(2) Å, c = 21.551(4) Å, alpha = 84.40(3) degrees, beta = 84.03(3) degrees, gamma = 60.86(3) degrees, V = 1924.9(6) Å(3), Z = 2. Crystal data for 5: triclinic space group P&onemacr;, a = 11.850(2)Å, b = 13.888(3) Å, c = 18.716(4) Å, alpha = 86.08(3) degrees, beta = 89.15(3) degrees, gamma = 83.36(3) degrees, V = 3052.3(11) Å(3), Z = 4.

Journal Article↗