We demonstrate that [Cp*Rh] complexes bearing substituted 2,2'-bipyridyl ligands are effective hydrogen evolution catalysts (Cp*=η -pentamethylcyclopentadienyl). Disubstitution (at the 4 and 4' positions) of the bipyridyl ligand (namely -tBu, -H, and -CF ) modulates the catalytic overpotential, in part due to involvement of the reduced ligand character in formally rhodium(I) intermediates. These reduced species are synthesized and isolated here; protonation results in formation of complexes bearing the unusual η -pentamethylcyclopentadiene ligand, and the properties of these protonated intermediates further govern the catalytic performance. Electrochemical studies suggest that multiple mechanistic pathways are accessible, and that the operative pathway depends on the applied potential and solution conditions. Taken together, these results suggest synergy in metal-ligand cooperation that modulates the mechanisms of fuel-forming catalysis with organometallic compounds bearing multiple non-innocent ligands.

Background Iron depletion/deficiency in blood donors frequently results in deferrals for low hemoglobin, yet blood centers remain reluctant to dispense iron replacement therapy to donors. Study Design and Methods During a 39-month period, 1236 blood donors deferred for hemoglobin <12.5 g/dL and 400 non-deferred control donors underwent health history screening and laboratory testing (CBC, iron studies). Iron depletion and deficiency were defined as ferritin of 9–19 mcg/L and <9 mcg/L in females and 18–29 mcg/L and <18 mcg/L in males. Deferred donors and iron-deficient control donors were given a 60-pack of ferrous sulfate 325 mg tablets, and instructed to take one tablet daily. Another 60-pack was dispensed at all subsequent visits. Results In the low hemoglobin group, 30% and 23% of females and 8% and 53% of males had iron depletion or deficiency, respectively, compared with 29% and 10% of females and 18% and 21% of males in the control group. Iron depleted/deficient donors taking iron showed normalization of iron-related laboratory parameters, even as they continued to donate. Compliance with oral iron was 68%. Adverse gastrointestinal effects occurred in 21% of donors. The study identified 13 donors with serious medical conditions, including eight with GI bleeding. No donors had malignancies or hemochromatosis. Conclusion Iron depletion or deficiency was found in 53% of female and 61% of male low hemoglobin donors, and in 39% of female and male control donors. Routine administration of iron replacement therapy is safe, effective, and prevents the development of iron depletion/deficiency in blood donors.

Background Pica and restless legs syndrome (RLS) are associated with iron depletion and deficiency. The presence of pica and RLS was prospectively assessed in blood donors. Methods During a 39-month period, 1236 donors deferred for fingerstick hemoglobin <12.5 g/dL and 400 non-deferred “control” donors underwent health screening and laboratory testing (CBC, ferritin, iron, transferrin). Pica and RLS were assessed by direct questioning. Deferred donors and iron-deficient control donors were given ferrous sulfate 325 mg daily for 60 days. Reassessments were performed and additional iron tablets dispensed at subsequent visits. Results Pica was reported in 11% of donors with iron depletion/deficiency, compared with 4% of iron-replete donors (p<0.0001). Pagophagia (ice pica) was most common and often of extraordinary intensity. Female sex, younger age, and lower MCV and transferrin saturation values were strongly associated with pica. Donors with pica given iron reported a marked reduction in the desire to consume the non-nutritive substance by day 5–8 of therapy, with disappearance of symptoms by day 10–14. RLS was reported in 16% of subjects with iron depletion/deficiency compared with 11% of iron-replete donors (p=0.012). Iron replacement generally resulted in improvement of RLS symptoms, however, at least 4–6 weeks of iron therapy was necessary. Conclusion The presence of pica is associated with a high probability of iron depletion/deficiency in blood donors; however, RLS lacks a strong correlation in this population. Screening questions for pagophagia may be useful in the ascertainment of iron deficiency in donors and may identify those who would benefit from oral iron.

A series of [Cp*Rh] complexes (Cp* = η5-pentamethylcyclopentadienyl) bearing the κ2-[P,N]-8-(diphenylphosphino)­quinoline (PQN) ligand have been prepared and characterized. Chemical or electrochemical reduction of the rhodium­(III) form generates an isolable rhodium­(I) complex; this rhodium­(I) complex reacts with a range of organic acids to yield a rhodium­(III) hydride bearing [Cp*] in the η5 mode and [PQN] in the expected κ2 mode. Solid-state structures of these three compounds from X-ray diffraction studies reveal only small changes in the intraligand bond distances across the series, suggesting the redox events associated with interconversion of these compounds are primarily metal centered. Cyclic voltammetry data show that the rhodium­(III) chloride complex undergoes a two-electron reduction at −1.19 V vs ferrocenium/ferrocene, whereas the analogous solvento rhodium­(III) acetonitrile complex undergoes two sequential one-electron reductions. The rhodium­(III) hydride undergoes an irreversible, ligand-centered reduction near −1.75 V vs ferrocenium/ferrocene. Carrying out this reduction alone or in the presence of added of triethylammonium as a source of protons results in only modest yields of H2, as shown by bulk electrolyses and chemical reduction experiments. These results are discussed in the context of recent work with [Cp*Rh] complexes bearing more symmetric 2,2′-bipyridyl and diphosphine ligands.

2283 Background: Pica and restless legs syndrome (RLS) are associated with iron depletion and deficiency. Pica refers to the compulsive craving for and persistent consumption of non-nutritive substances. Pagophagia, the pathological consumption of ice, is a specific pica strongly associated with iron deficiency. RLS is a neurological movement disorder characterized by uncomfortable sensations in the lower extremities, with a compelling urge to move the extremities to relieve the discomfort. Primary RLS is a central nervous system disorder; however, secondary RLS may be caused or exacerbated by iron deficiency. The purpose of this study was to prospectively assess the prevalence of pica and RLS in blood donors presenting to a hospital-based donor center, to correlate the findings with donor hemoglobin and iron levels, and to study the effects of oral iron replacement on the resolution of symptoms. Methods: During a 39-month period, 1236 blood donors deferred for fingerstick hemoglobin <12.5 g/dL and 400 non-deferred “control” donors underwent health screening and laboratory testing (CBC, ferritin, iron, transferrin). Iron deficiency was defined as a ferritin level below the institutional reference range of 9 mcg/L in females and 18 mcg/L in males. Iron depletion was defined as a ferritin of 9 – 19 mcg/L in females and 18 – 29 mcg/L in males. Pica and RLS were assessed by direct questioning. Deferred donors and iron-deficient control donors were given ferrous sulfate 325 mg daily for 60 days. Reassessments were performed and additional iron tablets dispensed at subsequent visits. Results: Pica was reported in 11% of donors with iron depletion/deficiency, compared with 4% of iron-replete donors (p<0.0001). The prevalence of pica rose to 21% in females with ferritin <9 mcg/L. Pagophagia (ice pica) was most common and was often of extraordinary intensity, with characteristics of an addiction. Donors with pagophagia given iron reported a marked reduction in the desire to eat ice by day 5–8 of therapy, with disappearance of symptoms by day 10–14. RLS was reported in 16% of subjects with iron depletion/deficiency compared with 11% of iron-replete donors (p=0.012). Iron replacement generally resulted in improvement of RLS symptoms, however, at least 4–6 weeks of iron therapy was necessary. The positive predictive values of pica and RLS in iron deficient/depleted blood donors were 73% and 58%, respectively. Conclusion: The presence of pica is highly predictive of iron depletion/deficiency in blood donors; however, RLS lacks a strong correlation in this population. Screening questions for pica, in particular pagophagia, may be useful in the ascertainment of iron depletion and deficiency in blood donors and may identify those who would benefit from oral iron therapy. Disclosures: No relevant conflicts of interest to declare.

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4,5-diazafluorene (daf) and 9,9’-dimethyl-4,5-diazafluorene (Me2daf) are structurally similar to the important ligand 2,2’-bipyridine (bpy), but significantly less is known about the redox and spectroscopic properties of metal complexes containing Me2daf as a ligand than those containing bpy. New complexes Mn(CO)3Br(daf) (2), Mn(CO)3Br(Me2daf) (3), and [Ru(Me2daf)3](PF6)2 (5) have been prepared and fully characterized to understand the influence of the Me2daf framework on their chemical and electrochemical properties. Structural data for 2, 3, and 5 from single-crystal X-ray diffraction analysis reveal a distinctive widening of the daf and Me2daf chelate angles in comparison to the analogous Mn(CO)3(bpy)Br (1) and [Ru(bpy)3]2+ (4) complexes. Electronic absorption data for these complexes confirm the electronic similarity of daf, Me2daf, and bpy, as spectra are dominated in each case by metal-to-ligand charge transfer bands in the visible region. However, the electrochemical properties of 2, 3, and 5 reveal that the redox-active Me2daf framework in 3 and 5 undergoes reduction at a slightly more negative potential than that of bpy in 1 and 4. Taken together, the results indicate that Me2daf could be useful for preparation of a variety of new redox-active compounds, as it retains the useful redox-active nature of bpy but lacks the acidic, benzylic C–H bonds that can induce secondary reactivity in complexes bearing daf.

BACKGROUND Apheresis donors are routinely evaluated with a complete blood count (CBC). Low red blood cell mean corpuscular volume (MCV) values (<80 fL) in the presence of an acceptable hemoglobin (Hb; ≥12.5 g/dL) could be due to iron deficiency or hemoglobinopathy. The etiology of a low MCV in a healthy apheresis donor population was assessed. METHODS Predonation samples for CBC were obtained from 1162 consecutive apheresis donors. Donors with a MCV of less than 80 fL were evaluated by CBC, iron studies (ferritin, serum iron, transferrin, percentage of transferrin saturation), and hemoglobin (Hb) electrophoresis. Iron deficiency was defined as a ferritin value below the reference range. Beta chain Hb variants were determined by Hb electrophoresis. Alpha thalassemia trait was presumed if the red blood cell (RBC) count was elevated, no variant Hbs were detected, and the iron studies were within normal ranges. RESULTS In a 19-month period, 33 of 1162 apheresis donors had low MCV values. Iron deficiency was present in 64%; 49% had isolated iron deficiency and 15% had iron deficiency plus hemoglobinopathy. Hemoglobinopathy without concomitant iron deficiency was found in the remaining 36%. CONCLUSION Iron deficiency is present in the majority of apheresis donors with repeatedly low MCV values and Hb levels of 12.5 g/dL or more. Hemoglobinopathy is also commonly present but may not be easily recognized in the setting of iron deficiency. The MCV is a useful screening tool to detect iron deficiency and hemoglobinopathy. Low MCV values should be investigated to determine if iron replacement therapy is indicated.