Actinide 2-metallabiphenylenes that satisfy Hückel's rule.

Aromaticity and antiaromaticity, as defined by Hückel's rule, are key ideas in organic chemistry, and are both exemplified in biphenylene1-3-a molecule that consists of two benzene rings joined by a four-membered ring at its core. Biphenylene analogues in which one of the benzene rings has been replaced by a different (4n + 2) π-electron system have so far been associated only with organic compounds4,5. In addition, efforts to prepare a zirconabiphenylene compound resulted in the isolation of a bis(alkyne) zirconocene complex instead6. Here we report the synthesis and characterization of, to our knowledge, the first 2-metallabiphenylene compounds. Single-crystal X-ray diffraction studies reveal that these complexes have nearly planar, 11-membered metallatricycles with metrical parameters that compare well with those reported for biphenylene. Nuclear magnetic resonance spectroscopy, in addition to nucleus-independent chemical shift calculations, provides evidence that these complexes contain an antiaromatic cyclobutadiene ring and an aromatic benzene ring. Furthermore, spectroscopic evidence, Kohn-Sham molecular orbital compositions and natural bond orbital calculations suggest covalency and delocalization of the uranium f2 electrons with the carbon-containing ligand.

One size does not fit all: Impact of hand size on ease of use of instruments for minimally invasive surgery.

BACKGROUND: Consideration of ergonomic factors is important for the practice of safe and efficient minimally invasive surgery (MIS). Surgeons with smaller glove sizes have previously been reported to have increased difficulties with some minimally invasive instruments. We aim to investigate hand anthropometrics and their relationship to surgeon comfort when using MIS instruments. METHODS: Male and female surgeons from two centres were surveyed on their experience of handling MIS instruments and images obtained of the dorsal and palmar aspects of their dominant hand. Photographs of hands were transformed to calibrated coordinates to enable anthropometric measurements of finger length and width as well as palm width and hand span photogrammetrically. Surgeon-perceived discomfort, fatigue, pressure points and techniques to mitigate difficulty handling instruments were compared to hand measurements. RESULTS: Questionnaires were completed by 58 surgeons; 20 (34%) were consultants, 17 (29%) were women. Glove size ranged from 6 to 8 (median 7.5). Male participants had significantly larger hands than females in all measured dimensions. Female surgeons and those with smaller finger and hand dimensions were significantly more likely to experience difficulty or discomfort across a range of variables when using MIS instruments. CONCLUSIONS: Surgeons with smaller hands reported increased problems handling MIS instruments. This represents an issue of equity in surgery, with women being more significantly affected than men. Hand size varies greatly between surgeons and anthropometric variability should be considered in design of MIS instruments.

Reduced brown adipose tissue-associated skin temperature following cold stimulation in children and adolescents with type 1 diabetes.

BACKGROUND: Brown adipose tissue (BAT) is essential to maintain body temperature. Its ability to convert chemical energy in glucose and free fatty acids to heat is conferred by a unique protein, UCP-1. BAT activity is greatest in children and adolescents, declining through adulthood. Blood glucose concentrations outside the normal nondiabetic range are common in type 1 diabetes and hyperglycaemia leads to insulin resistance in muscle and white adipose tissue, but whether this applies to BAT, is not known. METHOD: To investigate the effect of type 1 diabetes on BAT activity, we measured the supraclavicular temperature of 20 children with type 1 diabetes and compared them to 20 age-matched controls, using infrared thermography. RESULTS: The diabetes group had lower stimulated supraclavicular temperatures (diabetes group: 35.03 (34.76-35.30)°C; control group: 35.42 (35.16-35.69)°C; p = 0.037) and a reduced response in relative temperature following cold stimulation, after adjusting for BMI (diabetes group: 0.11 (0.03-0.18)°C; control group: 0.22 (0.15-0.29)°C; p = 0.034). In the diabetes group, there was no association between glycaemic measures and supraclavicular temperatures, but the method of insulin delivery may significantly affect the change in supraclavicular temperature with stimulation (injections: 0.01 (-0.07-0.09)°C; pump: 0.15 (0.04-0.26)°C; p = 0.028). CONCLUSIONS: While further work is needed to better understand the glucose-insulin-BAT relationship, one possible explanation for the reduced supraclavicular temperature is that exogenous, unlike endogenous, insulin, is not suppressed by the activity of the sympathetic nervous system, preventing lipolysis-driven activation of BAT.

Skeletal and Dental Habilitation of Residual Alveolar and Maxillary Clefts.

ABSTRACT: Management of residual clefts of the alveolus and maxilla requires the coordinated effort of multiple members of the craniofacial team including surgeon, orthodontist, and when teeth are hypoplastic or absent, the prosthodontist to achieve complete habilitation. Such cooperation among specialists begins early in the patient's life and continues through completion of care.Although numerous publications on this topic exist, few present definitive multidisciplinary reconstructive outcomes with longterm results. In this review paper, the authors present our comprehensive, multidisciplinary protocols, experience, and techniques as they have evolved with over 35 years of practice at our Craniofacial Center.Details of our updated protocols for each intervention and procedure, including our current thoughts on appropriate timing, follow up and advantages from the incorporation of current technologies are discussed. Close cooperation among specialists at all stages of care, the use of evolving technology, and adherence to, and modification where indicated, of time honored team protocols enables us to consistently achieve successful functional and esthetic outcomes, while minimizing complications.

Infrared Thermography.

Historically, brown adipose tissue has been elusive and not easy to detect, hence its relative obscurity in human physiology until its rediscovery in 2009. At that point, it was proven that the symmetrical artefacts frequently detected on positron emission tomography-computed tomography (PET-CT), which resolved if the environment was kept warm, were brown adipose tissue deposits. PET-CT has remained the stalwart of human brown adipose tissue research and is still considered the gold standard. However, PET-CT exposes the participant to ionising radiation, limiting studies to large, but retrospective, review of clinical imaging or a small-scale, but prospective, design. Within this context, alternative imaging modalities have been sought. Due to the heat-generating properties of brown adipose tissue, infrared thermography is a natural candidate for measuring its activity and the supraclavicular depot is relatively superficial, allowing detection of the heat signature. Infrared thermography is a non-invasive, non-contact technique for measuring temperature remotely. Recent developments in image analysis techniques have facilitated the use of infrared thermography to study brown adipose tissue activation in populations, and in ways, not previously feasible.

Facial Gender Affirmation Surgery: Craniomaxillofacial Imaging.

Facial procedures directed at gender affirmation are uniquely tailored to the individual patient and may affect soft tissue and skeletal structures over the entire face-from the chin through the upper forehead. Complete photographic and radiographic documentation that addresses these areas is important from the perspectives of surgical planning, evaluation of outcomes, research purposes, and communication between patient and provider, and amongst treating professionals. This work outlines pertinent skeletal anatomy that is uniquely addressed in gender affirmation procedures and means by which it can be effectively imaged. It provides historical insight into the evolution of computerized-tomography-based imaging. The authors provide detailed protocols for photodocumentation and computerized-tomography based skeletal imaging at their center.

Synthesis, Characterization, and Density Functional Theory Analysis of Uranium and Thorium Complexes Containing Nitrogen-Rich 5-Methyltetrazolate Ligands.

Two nitrogen-rich, isostructural complexes of uranium and thorium, (C5Me5)2U[η(2)-(N,N')-tetrazolate]2 (7) and (C5Me5)2Th[η(2)-(N,N')-tetrazolate]2 (8), containing 5-methyltetrazolate, have been synthesized and structurally characterized by single-crystal X-ray diffraction, electrochemical methods, UV-visible-near-IR spectroscopy, and variable-temperature (1)H NMR spectroscopy. Density functional theory (DFT) calculations yield favorable free energies of formation (approximately -375 kJ/mol) and optimized structures in good agreement with the experimental crystal structures. Additionally, calculated NMR chemical shifts of 7 and 8 are in good agreement with the variable-temperature (1)H NMR experiments. Time-dependent DFT calculations of both complexes yield UV-visible spectroscopic features that are consistent with experiment and provide assignments of the corresponding electronic transitions. The electronic transitions in the UV-visible spectroscopic region are attributed to C5Me5 ligand-to-metal charge transfer. The low-lying molecular orbitals of the tetrazolate ligands (∼2 eV below the HOMO) do not contribute appreciably to experimentally observed electronic transitions. The combined experimental and theoretical analysis of these new nitrogen-rich uranium and thorium complexes indicates the tetrazolate ligand behaves primarily as a σ-donor.

Primary Overcorrection of the Unilateral Cleft Nasal Deformity: Quantifying the Results.

BACKGROUND: Because primary nasal correction by the time of lip repair has been incorporated into the treatment approach, many patients have benefitted from this combined procedure. However, primary nasal correction cannot guarantee an excellent result. Although overcorrection has been mentioned as a treatment rationale of the unilateral cleft lip nasal deformity, a detailed approach and quantitative evidence of the rationale are rare. This study evaluates whether overcorrection in the primary repair results in a quantitative improvement in nasal appearance. PATIENTS AND METHODS: In this retrospective study, the inclusion criteria were patients with complete unilateral cleft lip and palate who underwent primary lip and nose repair by the age of 3 to 4 months. Primary nasal overcorrection was achieved by application of muscle to septal base suture, alar cinching suture and Tajima reversed U incision method. Patients were further divided into an overcorrected (n = 19) and nonovercorrected group (n = 19). The following parameters were identified on basilar photos of all patients taken at least 12 months after repair, ratios of cleft to noncleft side in each patient were taken and the mean for each parameter calculated: Ac angle (ACA/ACA'), alar height (AH/AH'), alar width (AW/AW'), nostril height (NH/NH`), nostril width (NW/NW'), and columellar deviation from the midline (CD/NW). The means of the overcorrected and nonovercorrected groups were then compared using the t test. RESULTS: From all investigated measuremens, Alar height (AH/AH': overcorrected, 0.983 to nonovercorrected, 0.941; P = 0.03) and nostril height ratio (NH/NH') (NH/NH': covercorrected, 0.897 to nonovercorrected, 0.680; P = 0.003) showed statistically significant differences favoring the overcorrected group at least 12 months after surgery. CONCLUSIONS: Primary nasal overcorrection including muscle to columella base suture, alar cinch suture, and Tajima method resulted in quantitatively more long-term symmetric alae and nostril height compared to nonovercorrected patients.

New Twists and Turns for Actinide Chemistry: Organometallic Infinite Coordination Polymers of Thorium Diazide.

Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

Transcaruncular approach to the isolated medial orbital wall fracture: technical perspective and cadaveric dissection.

With technologic progress in imaging for patients with trauma, isolated medial orbital wall fractures have become an increasingly appreciated injury. Given that these injuries may cause deformity and functional deficit, reconstruction is warranted in some cases. Surgical approaches to the medial orbit have evolved, and there are particular benefits of the transcaruncular approach. This approach was used to reconstruct isolated medial orbital wall fractures for 9 patients over a 33-month period. A cadaver dissection demonstrating the approach combined with skull images is presented to illustrate anatomic details and technical points of the dissection.

Applicability of randomized trials in radiation oncology to standard clinical practice.

BACKGROUND: Randomized controlled trials (RCTs) are commonly used to inform clinical practice; however, it is unclear how generalizable RCT data are to patients in routine clinical practice. The authors of this report assessed the availability and applicability of randomized evidence guiding medical decisions in a cohort of patients who were evaluated for consideration of definitive management in a radiation oncology clinic. METHODS: The medical records of consecutive, new patient consultations between January and March 2007 were reviewed. Patient medical decisions were classified as those with (Group 1) or without (Group 2) available, relevant level I evidence (phase 3 RCT) supporting recommended treatments. Group 1 medical decisions were further divided into 3 groups based on the extent of fulfilling eligibility criteria for each RCT: Group 1A included decisions that fulfilled all eligibility criteria; Group 1B, decisions that did not fulfill at least 1 minor eligibility criteria; or Group 1C, decisions that did not fulfill at least 1 major eligibility criteria. Patient and clinical characteristics were tested for correlations with the availability of evidence. RESULTS: Of the 393 evaluable patients, malignancies of the breast (30%), head and neck (18%), and genitourinary system (14%) were the most common presenting primary disease sites. Forty-seven percent of all medical decisions (n = 451) were made without available (36%) or applicable (11%) randomized evidence to inform clinical decision making. Primary tumor diagnosis was significantly associated with the availability of evidence (P < .0001). CONCLUSIONS: A significant proportion of medical decisions in an academic radiation oncology clinic were made without available or applicable level I evidence, underscoring the limitations of relying solely on RCTs for the development of evidence-based health care.

Mucoepidermoid carcinoma of the parotid as a secondary malignancy after chemotherapy in a child with neuroblastoma.

Secondary neoplasms are not reported frequently after neuroblastoma, which until recently was a cancer with limited long-term survival. Although salivary gland tumors in children and adolescents may be idiopathic, they are seen more often after head and neck radiation. We report a child with stage 4 neuroblastoma treated with high-dose multiagent chemotherapy without radiation therapy to his neck who, within 1 year of treatment, developed a low-grade but large and locally aggressive mucoepidermoid carcinoma of his parotid gland further characterized by a t(11;19)(q21;p13.1). Our patient extends the spectrum of secondary neoplasms after neuroblastoma.

Predicting the need for palliative thoracic radiation after first-line chemotherapy for advanced nonsmall cell lung carcinoma.

BACKGROUND: The objective of this secondary analysis was to identify patients with selected stage IIIB/IV nonsmall cell lung carcinoma and good performance status who were at high risk for requiring subsequent palliative thoracic radiotherapy after initial treatment with first-line chemotherapy. METHODS: The authors conducted a pooled analysis of patients at a single institution who enrolled onto 10 prospective phase 2 and 3 clinical trials that involved first-line, platinum-based chemotherapy. Baseline lung-related characteristics before trial enrollment were analyzed as possible prognostic factors for freedom from pulmonary events (defined either as subsequent thoracic radiation or as a new collapsed lung, which is an indication for thoracic radiation). RESULTS: Of 244 consecutive patients who were reviewed, 42 patients received a palliative course of thoracic radiation, 40 exhibited evidence of new lobar collapse on follow-up chest imaging, and 14 received thoracic radiation for lobar collapse. On univariable analysis, pulmonary symptoms (P = .043) or pneumonia at presentation (P = .0001), increasing size of hilar disease (P < .0001), and evidence of obstruction of major bronchi or vessels (P = .0003) were associated with subsequent pulmonary events. On multivariable analysis, hilar disease measuring >3 cm (hazard ratio, 1.8; P = .003) and prechemotherapy pneumonia (hazard ratio, 2.1; P = .009) were associated with pulmonary events; patients who had both risk factors or hilar disease >5 cm in greatest dimension exhibited a >50% risk of subsequent events. CONCLUSIONS: Patients with bulky hilar disease and a history of pneumonia at presentation were at high risk for requiring palliative thoracic radiation. The authors propose studying these patients to determine whether early thoracic radiation may be beneficial by preserving quality of life and performance status.

Complications of pediatric facial fractures.

Pediatric facial fractures account for only 5% of all facial fractures, with even a much lower incidence in children younger than 5 years (1%-1.5%). The evolution of principles in the management of pediatric facial fractures and the differences in management between adult and pediatric patients have been well documented in the literature. Pediatric facial fracture management presents unique challenges because it might affect growth in the area specific to the trauma segment. Children are, in several ways, at a regenerative advantage: greater osteogenic potential, faster healing rate, primary dentition that is thereby temporary, and the capacity for significant dental compensation. Perhaps because of this, complications such as infection, malunion, nonunion, and postinjury malocclusion are relatively rare compared with the adult population. In this article, we will focus on different approaches to complications that arise after pediatric fracture management.

Stereotactic body radiotherapy (SBRT): Technological innovation and application in gynecologic oncology.

OBJECTIVES: Stereotactic body radiotherapy (SBRT) is a novel form of noninvasive, highly conformal radiation treatment that delivers a high dose to tumor. The advantage of the technique resides in its ability to provide a high dose to tumor but spare normal tissues to an extent not previously possible. In this paper we will provide an introduction and review of this technology with regard to its use in gynecologic malignancies. Preliminary results from our experience are presented for the purpose of illustrating the range of SBRT applications in gynecologic oncology. METHODS: A comprehensive literature review was conducted and our experience from the past three years was reviewed. RESULTS: Six case series are published that report results of SBRT for gynecologic malignancies. Sixteen gynecologic patients have been treated with SBRT at our institution. Treatment sites include pelvic and periaortic nodes (9 patients), oligometastatic disease (2), and cervical or endometrial primary tumors when other conventional external radiation or brachytherapy techniques were unsuitable (5). Preliminary follow-up at a median of 11 months (range, 0.3-33 months) demonstrates 79% locoregional control, 43% distant failure, and 50% overall survival. CONCLUSIONS: SBRT boosts to macroscopic periaortic node recurrences and other sites seem to provide local control and a possibility of long-term disease-free survival in carefully selected patients. Previously this had been difficult to achieve with conventional radiotherapy because of the proximity of periaortic nodes to small bowel. SBRT also offers a novel approach for minimally invasive treatment in the management of gynecological cancer where current surgical and radiotherapy techniques are unsuitable.

Semi-automated analysis of supraclavicular thermal images increases speed of brown adipose tissue analysis without increasing variation in results.

Interest in brown adipose tissue remains high a decade after it was determined to be present outside of the neonatal period. In vivo imaging, however, has remained a challenge due to the lack of a imaging modality suitable for large healthy-volunteer studies, post-prandial investigations and vulnerable groups, such as children. Infrared thermography is increasingly accepted as a valid, non-invasive and flexible alternative but there is a wide approach to analysis between different groups. Defining the region of interest with anatomical borders rather than using a simple polygon may have advantages in terms of consistency but makes image analysis slower, limiting some applications. Our novel semi-automated method, using a custom-built graphical user interface, allows an 86% improvement in speed of image analysis (54.9 (38.3-71.4) seconds/image) without increases in variation between analysers or with repeated analysis. The improved efficiency demonstrated makes feasible larger studies, longer imaging periods or increased image acquisition frequency, providing an opportunity to study novel features of brown adipose tissue function.

Students' Views towards Sars-Cov-2 Mass Asymptomatic Testing, Social Distancing and Self-Isolation in a University Setting during the COVID-19 Pandemic: A Qualitative Study.

We aimed to explore university students' perceptions and experiences of SARS-CoV-2 mass asymptomatic testing, social distancing and self-isolation, during the COVID-19 pandemic. This qualitative study comprised of four rapid online focus groups conducted at a higher education institution in England, during high alert (tier 2) national COVID-19 restrictions. Participants were purposively sampled university students (n = 25) representing a range of gender, age, living circumstances (on/off campus), and SARS-CoV-2 testing/self-isolation experiences. Data were analysed using an inductive thematic approach. Six themes with 16 sub-themes emerged from the analysis of the qualitative data: 'Term-time Experiences', 'Risk Perception and Worry', 'Engagement in Protective Behaviours', 'Openness to Testing', 'Barriers to Testing' and 'General Wellbeing'. Students described feeling safe on campus, believed most of their peers are adherent to protective behaviours and were positive towards asymptomatic testing in university settings. University communications about COVID-19 testing and social behaviours need to be timely and presented in a more inclusive way to reach groups of students who currently feel marginalised. Barriers to engagement with SARS-CoV-2 testing, social distancing and self-isolation were primarily associated with fear of the mental health impacts of self-isolation, including worry about how they will cope, high anxiety, low mood, guilt relating to impact on others and loneliness. Loneliness in students could be mitigated through increased intra-university communications and a focus on establishment of low COVID-risk social activities to help students build and enhance their social support networks. These findings are particularly pertinent in the context of mass asymptomatic testing programmes being implemented in educational settings and high numbers of students being required to self-isolate. Universities need to determine the support needs of students during self-isolation and prepare for the long-term impacts of the pandemic on student mental health and welfare support services.

Nature of bonding in complexes containing "supershort" metal-metal bonds. raman and theoretical study of M2(dmp)4 [M = Cr (natural abundance Cr, 50Cr, and 54Cr) and Mo; dmp = 2,6-dimethoxyphenyl].

We report an investigation of complexes of the type M(2)(dmp)(4) (M = Mo, Cr; dmp = 2,6-dimethoxyphenyl) using resonance Raman (RR) spectroscopy, Cr isotopic substitution, and density functional theory (DFT) calculations. Assignment of the Mo-Mo stretching vibration in the Mo(2) species is straightforward, as evidenced by a single resonance-enhanced band at 424 cm(-1), consistent with an essentially unmixed metal-metal stretch, and overtones of this vibration. On the other hand, the Cr(2) congener has no obvious metal-metal stretching mode near 650-700 cm(-1), where empirical predictions based on the Cr-Cr distance as well as DFT calculations suggest that this vibration should appear if unmixed. Instead, three bands are observed at 345, 363, and 387 cm(-1) that (a) have relative RR intensities that are sensitive to the Raman excitation frequency, (b) exhibit overtones and combinations in the RR spectra, and (c) shift in frequency upon isotopic substitution ((50)Cr and (54)Cr). DFT calculations are used to model the vibrational data for the Mo(2) and Cr(2) systems. Both the DFT results and empirical predictions are in good agreement with experimental observations in the Mo(2) complex, but both, while mutually consistent, differ radically from experiment in the Cr(2) complex. Our experimental and theoretical results, especially the Cr isotope shifts, clearly demonstrate that the potential energy of the Cr-Cr stretching coordinate is distributed among several normal modes having both Cr-Cr and Cr-ligand character. The general significance of these results in interpreting spectroscopic observations in terms of the nature of metal-metal multiple bonding is discussed.

Actinide redox-active ligand complexes: reversible intramolecular electron-transfer in U(dpp-BIAN)2/U(dpp-BIAN)2(THF).

Actinide complexes of the redox-active ligand (dpp-BIAN)(2-) (dpp-BIAN = 1,2-bis(2,6-diisopropylphenylimino)acenaphthylene), U(dpp-BIAN)(2) (1), U(dpp-BIAN)(2)(THF) (1-THF), and Th(dpp-BIAN)(2)(THF) (2-THF), have been prepared. Solid-state magnetic and single-crystal X-ray data for complex 1 indicate a ground-state U(IV)-pi*(4) configuration, whereas a (dpp-BIAN)(2-)-to-uranium electron transfer occurs for 1-THF, resulting in a U(III)-pi*(3) ground configuration. The solid-state magnetic data also indicate that interconversion between the two forms of the complex is possible, limited only by the ability of tetrahydrofuran (THF) vapor to penetrate the solid upon cooling of the sample. In contrast to those in the solid state, spectroscopic data acquired in THF indicate only the presence of the U(IV)-pi*(4) form for 1-THF in solution, evidenced by electronic absorption spectra and by measurement of the solution magnetic moment in THF-d(8) using the Evans method. Also reported is the electrochemistry of the complexes collected in CH(2)Cl(2), CF(3)C(6)H(5), and THF. As expected from the solution spectroscopic data, only small differences are observed in half-wave potentials of ligand-based processes in the presence of THF, consistent with the solution U(IV)-pi*(4) configuration of the complexes in all cases. Density functional theory calculations were undertaken for complexes 1 and 1-THF to determine if intrinsic energetic or structural factors underlie the observed charge-transfer process. While the calculated optimized geometries agree well with experimental results, it was not possible to arrive at a convergent solution for 1-THF in the U(III)-pi*(3) configuration. However, perturbations in the orbital energies in 1 versus 1-THF for the U(IV)-pi*(4) configuration do point to a diminished highest occupied molecular orbital-lowest unoccupied molecular orbital energy gap in 1-THF, consistent with the solid-state magnetic data. These results represent the first example of a stable and well-defined, reversible intramolecular electron transfer in an actinide complex with redox-active ligands.

Comparative study of f-element electronic structure across a series of multimetallic actinide and lanthanoid-actinide complexes possessing redox-active bridging ligands.

A comparative examination of the electronic interactions across a series of trimetallic actinide and mixed lanthanide-actinide and lanthanum-actinide complexes is presented. Using reduced, radical terpyridyl ligands as conduits in a bridging framework to promote intramolecular metal-metal communication, studies containing structural, electrochemical, and X-ray absorption spectroscopy are reported for (C(5)Me(5))(2)An[-N horizontal lineC(Bn)(tpy-M{C(5)Me(4)R}(2))](2) (where An = Th(IV), U(IV); Bn = CH(2)C(6)H(5); M = La(III), Sm(III), Yb(III), U(III); R = H, Me, Et) to reveal effects dependent on the identities of the metal ions and R-groups. The electrochemical results show differences in redox energetics at the peripheral "M" site between complexes and significant wave splitting of the metal- and ligand-based processes indicating substantial electronic interactions between multiple redox sites across the actinide-containing bridge. Most striking is the appearance of strong electronic coupling for the trimetallic Yb(III)-U(IV)-Yb(III), Sm(III)-U(IV)-Sm(III), and La(III)-U(IV)-La(III) complexes, [8](-), [9b](-), and [10b](-), respectively, whose calculated comproportionation constant K(c) is slightly larger than that reported for the benchmark Creutz-Taube ion. X-ray absorption studies for monometallic metallocene complexes of U(III), U(IV), and U(V) reveal small but detectable energy differences in the "white-line" feature of the uranium L(III)-edges consistent with these variations in nominal oxidation state. The sum of these data provides evidence of 5f/6d-orbital participation in bonding and electronic delocalization in these multimetallic f-element complexes. An improved, high-yielding synthesis of 4'-cyano-2,2':6',2''-terpyridine is also reported.