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ABSTRACT: The title salt, [K(C(12)H(24)O(6))][Fe(C(8)H(12))(C(10)H(8))], is the only known naphthalene complex containing iron in a formally negative oxidation state. Each (naphthalene)(1,5-cod)ferrate(-I) anion is in contact with one (18-crown-6)potassium cation via K⋯C contacts to the outer four carbon atoms of the naphthalene ligand (cod = 1,5-cyclo-octa-diene, 18-crown-6 = 1,4,7,10,13,16-hexa-oxacyclo-octa-deca-ne). When using the midpoints of the coordinating olefin bonds, the overall geometry of the coordination sphere around iron can be best described as distorted tetra-hedral. The naphthalene fold angle between the plane of the iron-coordinating butadiene unit and the plane containing the exo-benzene moiety is 19.2 (1)°.
Acta Crystallographica Section E Structure Reports Online 10/2012; 68(Pt 10):m1230-1. · 0.35 Impact Factor
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ABSTRACT: The title salt, [K(C(18)H(36)N(2)O(6))][Co(C(2)H(4))(4)], is one of only two known homoleptic ethyl-enemetalates. The cation and anion are well separated, which gives an unperturbed tetra-hedral anion as is expected for a formally Co(-I)d(10) metal center. The considerable elongation of the C=C bonds of the ethyl-ene ligands [average 1.401 (6) Å], relative to that of free ethyl-ene (1.333 Å), is consistent with metal→π* back-bonding models. One arm of the 2.2.2-cryptand (4,7,13,16,21,24-hexa-oxa-1,10-diaza-bicyclo-[8.8.8]hexa-cosa-ne) complexant is disordered and was modeled over two positions with a refined occupancy ratio of 0.559 (2):0.441 (2). In the crystal, the cationic K(2.2.2-cryptand) units are linked via C-H⋯O hydrogen bonds, forming inversion dimers. There are no other significant inter-molecular inter-actions in the crystal structure.
Acta Crystallographica Section E Structure Reports Online 10/2012; 68(Pt 10):m1257-8. · 0.35 Impact Factor
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ABSTRACT: Reductions of CoBr(2) or cobaltocene by 3 equiv of potassium anthracene radical anion in tetrahydrofuran (THF) afford 60-80% yields of bis(anthracene)cobaltate(1-) (1), of interest as a readily accessible and quite labile source of spin-paired atomic Co(-). Although the unsolvated potassium salt of 1 is thermally unstable at 20 °C, the [K(18-crown-6)(THF)(2)](+) salt of 1 functions as a useful storable crystalline reagent for Co(-) in several reactions. Previously known classic cobaltates, [CoL(4)](-), for L = 1/2 (1,3-butadiene) (2), PF(3) (3), and P(OiPr)(3) (5), were obtained directly from 1 and structurally characterized for the first time. Anion 3 is noteworthy because it appears to possess the shortest known Co-P distance, av = 2.012(4) Å. Although the naphthalene analogue of 1 is not yet available as a pure substance, low-temperature reductions of CoBr(2) or cobaltocene by naphthalene radical anion in the presence of 1,5-cyclooctadiene (COD) afford variable yields (80-90% from CoCp(2)) of (naphthalene)(COD)cobaltate(1-) (10). Ready displacement of naphthalene in 10 by L = 1,3-butadiene, 2,2'-bipyridine, and COD occurs to give good yields of the respective [Co(L)(COD)](-), all of which have been structurally characterized. Both ligands in 10 are displaced by tert-butylisocyanide to afford [Co(CNtBu)(4)](-) (16), the first isolable and structurally characterized homoleptic alkylisocyanometalate. The molecular structure of 16 shows unprecedented bending of the isocyanides, av C-N-C = 137(2)°, for homoleptic isocyanide complexes.
Inorganic Chemistry 08/2012; 51(16):9076-94. · 4.60 Impact Factor
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ABSTRACT: The cation, anion, and solvent in the title compound, [K(C(18)H(36)N(2)O(6))][Co(C(8)H(12))(C(16)H(10))(2)]·0.5C(5)H(12), are well separated. The pentane solvent mol-ecules are found in channels along [100] and were modeled as disordered over crystallographic inversion centers. Using the mid-points of the coordinated olefins, the angle between the C(py)/C(py)-Co-C(py)/C(py) and the C(cod)/C(cod)-Co-C(cod)/C(cod) planes (py is pyrene and cod is cyclo-octa-diene) is 67.6 (2)°. Thus, the overall geometry of the coordination sphere around cobalt is best described as distorted tetra-hedral.
Acta Crystallographica Section E Structure Reports Online 07/2012; 68(Pt 7):m1013-4. · 0.35 Impact Factor
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ABSTRACT: The title compound, [Mo(C(10)H(8))(2)], was prepared from the naphthalene radical anion and MoCl(4)(thf)(2) (thf is tetra-hydro-furan). In the crystal, the mol-ecule is located on an inversion center. The Mo atom is equally disordered over two positions; the range of Mo-C distances is 2.2244 (19)-2.3400 (17) Å for both components of the disorder.
Acta Crystallographica Section E Structure Reports Online 02/2012; 68(Pt 2):m220. · 0.35 Impact Factor
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ABSTRACT: Patients who undergo vascular surgery are at increased risk of perioperative cardiovascular morbidity and mortality. The Revised Cardiac Risk Index (RCRI) is a validated and widely used bedside tool for estimating the risk of a perioperative major adverse myocardial event. We hypothesized that inclusion of the indication for surgery would add independent and prognostic information to the RCRI in predicting all-cause 30-day and 1-year mortality in open infrainguinal vascular surgical procedures.
This was a retrospective study of 603 patients who underwent open infrainguinal bypass vascular surgery between January 2002 and January 2008 at a tertiary care medical center. RCRI and indication for surgery were determined. The primary outcomes of interest were all-cause 30-day mortality (which included all in-hospital mortality, regardless of time) and all-cause 1-year mortality.
Overall 30-day mortality was 32 (5.3%). Independent risk factors for early death were RCRI score, being of age ≥80 years, American Society of Anesthesiologists Physical Status classification = 4, and emergency surgery. Overall 1-year mortality, including early deaths, was 114 (18.9%). Indication for surgery, RCRI score, age, American Society of Anesthesiologists Physical Status classification = 4, female sex, and emergency surgery were all independent predictors of 1-year mortality.
The RCRI score was associated with both 30-day and 1-year mortality in patients undergoing lower extremity bypass surgery. Indication for surgery was predictive of 1-year mortality but not of 30-day mortality.
Annals of Vascular Surgery 08/2011; 25(7):902-8. · 1.03 Impact Factor
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ABSTRACT: To investigate whether anesthesiologists' decisions to request preoperative cardiac evaluation (cardiologist consultation, echocardiography, and cardiac stress testing) before vascular surgery were influenced by patient comorbidity and magnitude of surgery; and to explore whether factors unrelated to the American College of Cardiology/American Heart Association (ACC/AHA) guidelines influence these decisions.
Survey instrument.
University medical center.
2,000 U.S. anesthesiologists who were mailed a survey.
Six factors in a hypothetical patient presenting for vascular surgery [gender, race (white vs. black), age (65 yrs vs. 85 yrs), comorbidities (sick vs. healthy), functional status, and magnitude of surgical stress] were evaluated. Respondents were asked about their demographics, practice patterns, and how they would manage the hypothetical patient.
Of 2,000 mailed surveys, 439 U.S. anesthesiologists responded (22%). Multivariate ordinal logistic regression analysis showed that anesthesiologists were more likely to recommend preoperative cardiology consultation for patients with more comorbidities [odds ratio = 5.53; 95% confidence interval (CI) = 3.76, 8.15], for those with poorer functional status (odds ratio = 1.45; 95% CI = 1.02, 2.07), for those undergoing a more significant surgery (odds ratio = 1.61; 95% CI = 1.13, 2.30), as the clinicians' estimated risk of perioperative myocardial infarction increased (P < 0.001), or if they only infrequently anesthetized patients such as the one described in the scenario (P = 0.05). They also would request a preoperative echocardiogram for patients with more comorbidities (odds ratio = 2.58; 95% CI = 1.80, 3.68) and for those undergoing a more significant surgery (odds ratio = 1.59; 95% CI = 1.12, 2.25). A preoperative stress test was recommended for patients with more comorbidities (odds ratio = 3.01; 95% CI = 2.06, 4.38) and for those with a more significant surgery (odds ratio = 1.74; 95% CI = 1.15, 2.63). Other factors associated with request for a preoperative stress test were female gender of the anesthesiologist (odds ratio = 1.79; 95% CI = 1.11, 2.87), those with less experience with such patients (P = 0.05), and those from New England (odds ratio = 2.16; 95% CI = 1.01, 4.62).
Anesthesiologists' preferences for preoperative cardiac evaluation are generally consistent with evidence-based and expert-based AHA/ACC guidelines. However, other physician factors (ie, gender, years in practice, and familiarity with the surgical procedure) also influenced these decisions.
Journal of clinical anesthesia 09/2010; 22(6):402-9. · 1.32 Impact Factor
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ABSTRACT: For the first time [N(PPh(3))(2)](+), or [PPN](+), has been shown to undergo an irreversible reaction with a transition metal complex under ambient conditions and affords a product containing a unique structural motif in which two phenyl groups on one PPh(3) substituent of [PPN](+) are ortho-metallated, while the third phenyl ring is hydrogenated to provide a tantalum bound 1,3-cyclohexadiene group.
Chemical Communications 12/2008; · 6.17 Impact Factor
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Angewandte Chemie International Edition 11/2008; 47(45):8692-5. · 13.45 Impact Factor
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Angewandte Chemie International Edition 02/2008; 47(3):484-9. · 13.45 Impact Factor
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ABSTRACT: Oxidation of [Ti(CO)(6)](2-) by thiuram disulfides, (R(2)NCS(2))(2), affords the first isolable mononuclear six-coordinate titanium(0) carbonyls, [Ti(CO)(4)(S(2)CNR(2))](-), which have unusual trigonal prismatic geometries and chemical and spectral properties that are remarkably similar to those of the 18-electron and seven-coordinate anion [Ti(CO)(4)(eta(5)-C(5)H(5))](-).
Chemical Communications 08/2007; · 6.17 Impact Factor
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ABSTRACT: It was hypothesized that anesthesiologists' decisions to provide perioperative beta-blockade during vascular surgery would be influenced more by physician factors than by those of their patients.
Mail survey.
Case presentation.
Four hundred thirty-nine anesthesiologists in the United States who responded to a survey.
By using Microsoft Word Mail Merge (Microsoft, Redmond, WA), 6 factors in a hypothetical patient presenting for vascular surgery (sex, race, age, comorbidities, functional status, and magnitude of surgical stress) were randomly varied.
The response rate was 22%. Self-reported propensity to use beta-blockade was significantly increased among anesthesiologists who worked in New England, among those who worked in larger hospitals, or who had received fellowship training. Among healthy patients, beta-blockers were more likely to be used for older than younger patients. Among sicker patients, however, the reverse was true. Heart rate triggers for beta-blockade use were higher than heart rates associated with improved outcomes in pivotal beta-blocker trials.
Preferences for perioperative beta-blockade use in vascular surgery patients are influenced by anesthesiologists' demographics as well as patient comorbidities or degree of surgical stress. This finding suggests that efforts to increase perioperative beta-blockade in high-risk vascular patients face significant barriers from some groups of clinicians.
Journal of Cardiothoracic and Vascular Anesthesia 07/2007; 21(3):330-6. · 1.64 Impact Factor
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ABSTRACT: Treatment of [M(CO)(6)](-), M = Nb, Ta, with Ag(+), I(2) or NO(+) in the presence of CNXyl provided [M(CNXyl)(7)](+), M(CNXyl)(6)I, or cis-[M(CNXyl)(4)(NO)(2)](+), which are isocyanide analogues of the unknown carbonyl complexes [M(CO)(7)](+), M(CO)(6)I, or cis-[M(CO)(4)(NO)(2)](+), respectively. Reduction of M(CNXyl)(6)I by cesium graphite gave the respective Cs[M(CNXyl)(6)], which have been structurally characterized and represent the first isolable homoleptic isocyanidemetalates for second or third row transition metals. Nitrosylation of [Ta(CNXyl)(6)](-) affords a rare example of a mononitrosyl tantalum complex, Ta(CNXyl)(5)NO, which is an isocyanide analogue of the unknown Ta(CO)(5)NO. This study emphasizes, inter alia, the remarkable versatility of the CNXyl ligand compared to CO in stabilizing various electronic environments at heavier group 5 metal centers.
Journal of the American Chemical Society 03/2007; 129(5):1141-50. · 9.91 Impact Factor
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Angewandte Chemie International Edition 02/2007; 46(4):598-600. · 13.45 Impact Factor
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Angewandte Chemie International Edition 02/2007; 46(32):6132-6. · 13.45 Impact Factor
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ABSTRACT: Treatment of [M(CO)6]-, M = Nb, Ta, with Ag+, I2 or NO+ in the presence of CNXyl provided [M(CNXyl)7]+, M(CNXyl)6I, or cis-[M(CNXyl)4(NO)2]+, which are isocyanide analogues of the unknown carbonyl complexes [M(CO)7]+, M(CO)6I, or cis-[M(CO)4(NO)2]+, respectively. Reduction of M(CNXyl)6I by cesium graphite gave the respective Cs[M(CNXyl)6], which have been structurally characterized and represent the first isolable homoleptic isocyanidemetalates for second or third row transition metals. Nitrosylation of [Ta(CNXyl)6]- affords a rare example of a mononitrosyl tantalum complex, Ta(CNXyl)5NO, which is an isocyanide analogue of the unknown Ta(CO)5NO. This study emphasizes, inter alia, the remarkable versatility of the CNXyl ligand compared to CO in stabilizing various electronic environments at heavier group 5 metal centers.
01/2007;
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Angewandte Chemie International Edition 12/2006; 45(43):7268-71. · 13.45 Impact Factor
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ABSTRACT: In the hyperlordotic position, the patient's hips are above the feet and head. This position has previously been associated with partial vena caval occlusion, increased venous pressures, and spinal cord infarction. We describe a case of fulminant hepatic failure after radical retropubic prostatectomy performed in the hyperlordotic position.
Anesthesia and analgesia 11/2006; 103(4):986-8. · 3.08 Impact Factor
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John E Ellis
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ABSTRACT: A brief history of substances containing s,p- and d-block metals in negative oxidation states is described. A classification of these species and discussions of formal oxidation state assignments for low-valent transition metals in complexes are included, along with comments on the innocent and noninnocent character of ligands in metalates. Syntheses of highly reduced carbonyl complexes formally containing transition metals in their lowest known oxidation states of III- and IV- are discussed. Atmospheric-pressure syntheses of early-transition-metal carbonyls involving alkali-metal polyarene-mediated reductions of non-carbonyl precursors have been developed. In the absence of carbon monoxide, these reactions afford homoleptic polyarenemetalates, including the initial species containing three aromatic hydrocarbons bound to one metal. In several instances, these metalates function as useful synthons for "naked" spin-paired atomic anions of transition metals.
Inorganic Chemistry 05/2006; 45(8):3167-86. · 4.60 Impact Factor
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Journal of Cardiothoracic and Vascular Anesthesia 05/2006; 20(2):259-68. · 1.64 Impact Factor
