Crystal structure of a dimeric β-diketiminate magnesium complex.

The solid-state structure of a dimeric β-diketiminate magnesium(II) complex is discussed. The compound, di-μ-iodido-bis-[(-{4-amino-1,5-bis-[2,6-bis-(propan-2-yl)phen-yl]pent-3-en-2-yl-idene}aza-nido-κ,')magnesium(II)] toluene sesquisolvate, [Mg(CHN)I]·1.5CH, crystallizes as two independent mol-ecules, each with 2/ crystallographic site symmetry, located at Wyckoff sites 2 and 2.

Differences in the cyclometalation reactivity of bisphosphinimine-supported organo-rare earth complexes.

The pyrrole-based ligand N,N'-((1H-pyrrole-2,5-diyl)bis(diphenylphosphoranylylidene))bis(4-isopropylaniline) (HL(B)) can be deprotonated and coordinated to yttrium and samarium ions upon reaction with their respective trialkyl precursors. In the case of yttrium, the resulting complex [L(B)Y(CH2SiMe3)2] (1) is a Lewis base-free monomer that is remarkably resistant to cyclometalation. Conversely, the analogous samarium complex [L(B)Sm(CH2SiMe3)2] is dramatically more reactive and undergoes rapid orthometalation of one phosphinimine aryl substituent, generating an unusual 4-membered azasamaracyclic THF adduct [κ(4)-L(B)Sm(CH2SiMe3)(THF)2] (2).

A cascade reaction: ring-opening insertion of dioxaphospholane into lutetium alkyl bonds.

Geometrically constrained dioxaphospholane rings were incorporated into a bis(phosphinimine)carbazole ligand (HL) in an effort to generate an ancillary ligand system that is capable of supporting reactive lutetium alkyl functionalities and resistant to cyclometalation reactivity. This new ligand was used to prepare a lutetium dialkyl species, LLu(CH2SiMe3)2; however, the complex exhibited low thermal stability at ambient temperature. This dialkyl compound was found to be highly susceptible to a cascading inter- and intramolecular reaction that resulted in the sole formation of an asymmetric bimetallic tetraalkoxide complex.

Secondary diphosphine and diphosphido ligands: synthesis, characterisation and group 1 coordination compounds.

Two types of secondary diphosphines, 1,8-(ArPH)2C14H8 (1a: Ar = Tripp, 2,4,6-triisopropylphenyl; 1b: Ar = Mes, 2,4,6-trimethylphenyl) and 1,3-((t)BuPHCH2)2C6H4 (2), based on rigid 1,8-anthracene and flexible m-xylyl frameworks, respectively, have been synthesized using different strategies. Compounds 1a and 1b were formed by nucleophilic aromatic substitution of a potassium organophosphido salt onto 1,8-difluoroanthracene, while compound 2 was obtained by addition of the Grignard reagent [1,3-(ClMgCH2)2C6H4]x to a dichloroorganophosphine, followed by reduction to the diphosphine. These compounds were isolated as ca.

Cyclometalative C-H bond activation in rare earth and actinide metal complexes.

Cyclometalative C-H bond activation is a process that is commonly encountered in the field of organometallic chemistry. In rare earth and actinide complexes, ligand cyclometalation is most prevalent in highly reactive alkyl and hydrido species. Numerous factors promote ligand cyclometalation and influence the rate at which it occurs.

Lanthanide complexes of the Kläui metalloligand, CpCo(P═O(OR)2)3: an examination of ligand exchange kinetics between isotopomers by electrospray mass spectrometry.

A series of lanthanide complexes, {[CpCo(P═O(OR)2)3]2Ln(H2O)x}(+)Cl(-) (Ln = Nd, 3; Eu, 4; Tb, 5; Yb, 6; R = Et, a; R = Ph, b) bearing two cobalt metalloligands were prepared. Electrospray mass spectrometry and thermogravimetric analysis suggest that the cations are either solvent-free or contain very weakly bound water molecules. The related complex {[CpCo(P═O(OPh)2)3]2Yb}(+) [CoCl3(THF)](-), 7, was crystallographically characterized, and the cation in this case was confirmed to be 6-coordinate and solvent-free.

Assessment of cardiac iron deposition in sickle cell disease using 3.0 Tesla cardiovascular magnetic resonance.

Many patients with sickle cell disease receive blood transfusions as a life-saving treatment. However, excess transfusions may lead to increased body iron burden. Specifically, heart failure due to cardiac iron overload is the leading cause of death in these patients.

Thermally stable rare earth dialkyl complexes supported by a novel bis(phosphinimine)pyrrole ligand.

A novel bis(phosphinimine)pyrrole based ligand (HL) and its synthesis are reported. Rare earth dialkyl complexes of the ligand, LLn(CH(2)SiMe(3))(2) (Ln = Er, Lu, Sc), have been prepared and found to exhibit high thermal stability in solution. The protio-ligand and dialkyl lanthanide complexes (Ln = Er, Lu) have been characterised by single crystal X-ray diffraction studies.

Measuring aortic pulse wave velocity using high-field cardiovascular magnetic resonance: comparison of techniques.

Background: The assessment of arterial stiffness is increasingly used for evaluating patients with different cardiovascular diseases as the mechanical properties of major arteries are often altered. Aortic stiffness can be noninvasively estimated by measuring pulse wave velocity (PWV). Several methods have been proposed for measuring PWV using velocity-encoded cardiovascular magnetic resonance (CMR), including transit-time (TT), flow-area (QA), and cross-correlation (XC) methods.

Three-directional myocardial phase-contrast tissue velocity MR imaging with navigator-echo gating: in vivo and in vitro study.

The study protocol was HIPAA compliant and institutional review board approved. Informed consent was obtained from all participants. The purpose of the study was to prospectively validate the capability of navigator-echo-gated phase-contrast magnetic resonance (MR) imaging for measurement of myocardial velocities in a phantom and to prospectively use the phase-contrast MR sequence to measure three-directional velocity in the myocardium in vivo in volunteers and in patients scheduled for cardiac resynchronization therapy.

Three-dimensional, time-resolved motion of the coronary arteries.

Background: Coronary artery motion can decrease image quality during coronary magnetic resonance angiography and computed tomography coronary angiography.

Purpose: To characterize the three-dimensional motion of the coronary arteries along the entire vessel length and to identify the temporal location and duration of periods of relatively low cardiac motion in patients with coronary artery disease.

Methods: Archived digital, biplane x-ray angiography films acquired at 30 frames per second with simultaneous electrocardiogram recording were reviewed for 15 patients with coronary artery disease.