Assessment of inter-centre agreement across multidisciplinary team meetings for patients with retroperitoneal sarcoma.

BACKGROUND: Decision-making in the management of patients with retroperitoneal sarcoma is complex and requires input from a number of different specialists. The aim of this study was to evaluate the levels of agreement in terms of resectability, treatment allocation, and organs proposed to be resected across different retroperitoneal sarcoma multidisciplinary team meetings. METHODS: The CT scans and clinical information of 21 anonymized retroperitoneal sarcoma patients were sent to all of the retroperitoneal sarcoma multidisciplinary team meetings in Great Britain, which were asked to give an opinion about resectability, treatment allocation, and organs proposed to be resected. The main outcome was inter-centre reliability, which was quantified using overall agreement, as well as the chance-corrected Krippendorff's alpha statistic. Based on the latter, the level of agreement was classified as: 'slight' (0.00-0.20), 'fair' (0.21-0.40), 'moderate' (0.41-0.60), 'substantial' (0.61-0.80), or 'near-perfect' (>0.80). RESULTS: Twenty-one patients were reviewed at 12 retroperitoneal sarcoma multidisciplinary team meetings, giving a total of 252 assessments for analysis. Consistency between centres was only 'slight' to 'fair', with rates of overall agreement and Krippendorff's alpha statistics of 85.4 per cent (211 of 247) and 0.37 (95 per cent c.i. 0.11 to 0.57) for resectability; 80.4 per cent (201 of 250) and 0.39 (95 per cent c.i. 0.33 to 0.45) for treatment allocation; and 53.0 per cent (131 of 247) and 0.20 (95 per cent c.i. 0.17 to 0.23) for the organs proposed to be resected. Depending on the centre that they had attended, 12 of 21 patients could either have been deemed resectable or unresectable, and 10 of 21 could have received either potentially curative or palliative treatment. CONCLUSIONS: Inter-centre agreement between retroperitoneal sarcoma multidisciplinary team meetings was low. Multidisciplinary team meetings may not provide the same standard of care for patients with retroperitoneal sarcoma across Great Britain.

Simultaneous Pancreas-Kidney Transplantation Versus Living Donor Kidney Transplantation Alone: an Outcome-Driven Choice?

PURPOSE OF REVIEW: The choice of optimum transplant in a patient with type 1 diabetes mellitus (T1DM) and chronic kidney disease stage V (CKD V) is not clear. The purpose of this review was to investigate this in more detail-in particular the choice between a simultaneous pancreas-kidney transplantation (SPKT) and living donor kidney transplantation (LDKT), including recent evidence, to aid clinicians and their patients in making an informed choice in their care. RECENT FINDINGS: Analyses of large databases have recently shown SPKT to have better survival rates than a LDKT in the long-term, despite an early increase in morbidity and mortality in SPKT recipients. This survival advantage has only been shown in those SPKT recipients with a functioning pancreas and not those who had early pancreas graft loss. The choice of SPKT or LDKT should not be based on patient and graft survival outcomes alone. Individual patient circumstances, preferences, and comorbidities, among other factors should form an important part of the decision-making process. In general, an SPKT should be considered in those patients not on dialysis and LDKT in those nearing or already on dialysis.

Stellar Multi-Photon Absorption Materials: Beyond the Telecommunication Wavelength Band.

Very large molecular two- and three-photon absorption cross-sections are achieved by appending ligated bis(diphosphine)ruthenium units to oligo(p-phenyleneethynylene) (OPE)-based "stars" with arms up to 7 phenyleneethynylene (PE) units in length. Extremely large three- and four-photon absorption cross-sections, through the telecommunications wavelengths range and beyond, are obtained for these complexes upon optimizing OPE length and the ruthenium-coordinated peripheral ligand. Multi-photon absorption (MPA) cross-sections are optimized with stars possessing arms 2 PE units in length. Peripheral ligand variation modifies MPA merit and, in particular, 4-nitrophenylethynyl ligand incorporation enhances maximal MPA values and "switches on" four-photon absorption (4PA) in these low molecular-weight complexes. The 4-nitrophenylethynyl-ligated 2PE-armed star possesses a maximal four-photon absorption cross-section of 1.8×10-108  cm8 s3 at 1750 nm, and significant MPA activity extending beyond 2000 nm.

An analysis of the survival outcomes of simultaneous pancreas and kidney transplantation compared to live donor kidney transplantation in patients with type 1 diabetes: a UK Transplant Registry study.

Transplant options for patients with type 1 diabetes and end-stage renal disease (ESRD) include deceased donor kidney, live donor kidney (LDK) and simultaneous pancreas-kidney (SPK) transplantation. The aim of this study was to compare outcomes between LDK and SPK for patients with type 1 diabetes and ESRD in the UK. Data on all SPK (n = 1739) and LDK (n = 385) transplants performed between January 2001 and December 2014 were obtained from the UK Transplant Registry. Unadjusted patient and kidney graft survival were calculated using the Kaplan-Meier method. Multivariate analysis of kidney graft and patient survival was performed using Cox proportional hazards regression. There was no significant difference in patient (P = 0.435) or kidney graft survival (P = 0.204) on univariate analysis. On multivariate analysis there was no association between LDK/SPK and patient survival [HR 0.71 (0.47-1.06), P = 0.095]. However, LDK was associated with an overall lower risk for kidney graft failure [HR 0.60 (0.38-0.94), P = 0.025]. SPK recipients with a functioning pancreas graft had significantly better kidney graft and patient survival than LDK recipients or those with a failed pancreas graft. SPK transplantation does not confer an overall survival advantage compared to LDK. However, those SPK recipients with a functioning pancreas have significantly better outcomes.

Dynamic Permutational Isomerism in a closo-Cluster.

Permutational isomers of trigonal bipyramidal [W2RhIr2(CO)9(η(5)-C5H5)2(η(5)-C5HMe4)] result from competitive capping of either a W2Ir or a WIr2 face of the tetrahedral cluster [W2Ir2(CO)10(η(5)-C5 H5)2] from its reaction with [Rh(CO)2(η(5)-C5HMe4)]. The permutational isomers slowly interconvert in solution by a cluster metal vertex exchange that is proposed to proceed by Rh-Ir and Rh-W bond cleavage and reformation, and via the intermediacy of an edge-bridged tetrahedral transition state. The permutational isomers display differing chemical and physical properties: replacement of CO by PPh3 occurs at one permutational isomer only, while the isomers display distinct optical power limiting behavior.

Record Multiphoton Absorption Cross-Sections by Dendrimer Organometalation.

Large increases in molecular two-photon absorption, the onset of measurable molecular three-photon absorption, and record molecular four-photon absorption in organic π-delocalizable frameworks are achieved by incorporation of bis(diphosphine)ruthenium units with alkynyl linkages. The resultant ruthenium alkynyl-containing dendrimers exhibit strong multiphoton absorption activity through the biological and telecommunications windows in the near-infrared region. The ligated ruthenium units significantly enhance solubility and introduce fully reversible redox switchability to the optical properties. Increasing the ruthenium content leads to substantial increases in multiphoton absorption properties without any loss of optical transparency. This significant improvement in multiphoton absorption performance by incorporation of the organometallic units into the organic π-framework is maintained when the relevant parameters are scaled by molecular weights or number of delocalizable π-electrons. The four-photon absorption cross-section of the most metal-rich dendrimer is an order of magnitude greater than the previous record value.

Syntheses, Spectroscopic, Electrochemical, and Third-Order Nonlinear Optical Studies of a Hybrid Tris{ruthenium(alkynyl)/(2-phenylpyridine)}iridium Complex.

The synthesis of fac-[Ir{N,C1'-(2,2'-NC5H4C6H3-5'-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡CH)}3] (10), which bears pendant ethynyl groups, and its reaction with [RuCl(dppe)2]PF6 to afford the heterobimetallic complex fac-[Ir{N,C1'-(2,2'-NC5H4C6H3-5'-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡C-trans-[RuCl(dppe)2])}3] (11) is described. Complex 10 is available from the two-step formation of iodo-functionalized fac-tris[2-(4-iodophenyl)pyridine]iridium(III) (6), followed by ligand-centered palladium-catalyzed coupling and desilylation reactions. Structural studies of tetrakis[2-(4-iodophenyl)pyridine-N,C1'](µ-dichloro)diiridium 5, 6, fac-[Ir{N,C1'-(2,2'-NC5H4C6H3-5'-C≡C-1-C6H2-3,5-Et2-4-C≡CH)}3] (8), and 10 confirm ligand-centered derivatization of the tris(2-phenylpyridine)iridium unit. Electrochemical studies reveal two (5) or one (6­10) Ir-centered oxidations for which the potential is sensitive to functionalization at the phenylpyridine groups but relatively insensitive to more remote derivatization. Compound 11 undergoes sequential Ru-centered and Ir-centered oxidation, with the potential of the latter significantly more positive than that of Ir(N,C'-NC5H4-2-C6H4-2)3. Ligand-centered π­π* transitions characteristic of the Ir(N,C'-NC5H4-2-C6H4-2)3 unit red-shift and gain in intensity following the iodo and alkynyl incorporation. Spectroelectrochemical studies of 6, 7, 9, and 11 reveal the appearance in each case of new low-energy LMCT bands following formal IrIII/IV oxidation preceded, in the case of 11, by the appearance of a low-energy LMCT band associated with the formal RuII/III oxidation process. Emission maxima of 6­10 reveal a red-shift upon alkynyl group introduction and arylalkynyl π-system lengthening; this process is quenched upon incorporation of the ligated ruthenium moiety on proceeding to 11. Third-order nonlinear optical studies of 11 were undertaken at the benchmark wavelengths of 800 nm (fs pulses) and 532 nm (ns pulses), the results from the former suggesting a dominant contribution from two-photon absorption, and results from the latter being consistent with primarily excited-state absorption.

Staging laparoscopy for hilar cholangiocarcinoma in 100 patients.

PURPOSE: Accurate preoperative radiological staging of hilar cholangiocarcinoma remains difficult, and a number of patients are found to have irresectable advanced tumours or occult metastases at exploration. Staging laparoscopy can improve the detection of irresectable disease, avoiding unnecessary laparotomy. This study examines the role of staging laparoscopy in hilar cholangiocarcinoma, with a focus on yield over different time periods and identification of preoperative factors increasing the risk of irresectable disease. METHODS: Retrospective case note review of all patients undergoing staging laparoscopy for radiologically resectable hilar cholangiocarcinoma, identified from the hepatobiliary multidisciplinary team database, was performed. RESULTS: One hundred consecutive patients underwent staging laparoscopy between 1998 and 2011. Of these, 34 patients were found to be irresectable due to metastatic disease, and 11, due to extensive local disease. Fifty patients proceeded to exploratory laparotomy following staging laparoscopy, and 36 % (18/50) of whom were found to have irresectable disease: 12 patients due to advanced local disease and 6 patients due to metastases. The overall yield of laparoscopy was 45 %, and the accuracy was 71 %. There was no significant difference in age, preoperative bilirubin, neutrophil/lymphocyte ratio, Ca19-9 levels or T stage between patients with resectable disease and with irresectable disease on laparoscopy. There was also no change in the yield of laparoscopy over time, despite advances in radiological imaging. CONCLUSION: In this series, staging laparoscopy avoided unnecessary laparotomy in 45 % of patients with radiologically resectable hilar cholangiocarcinoma. No factor was able to predict positive yield, and therefore, all patients with potentially resectable hilar cholangiocarcinoma should undergo staging laparoscopy.

Outcomes of Kidney Perfusion Techniques in Transplantation from Deceased Donors: A Systematic Review and Meta-Analysis.

The high demand for organs in kidney transplantation and the expansion of the donor pool have led to the widespread implementation of machine perfusion technologies. In this study, we aim to provide an up-to-date systematic review of the developments in this expanding field over the past 10 years, with the aim of answering the question: "which perfusion technique is the most promising technique in kidney transplantation?" A systematic review of the literature related to machine perfusion in kidney transplantation was performed. The primary outcome measure was delayed graft function (DGF), and secondary outcomes included rates of rejection, graft survival, and patient survival rates after 1 year. Based on the available data, a meta-analysis was performed. The results were compared with data from static cold storage, which is still the standard of care in many centers worldwide. A total of 56 studies conducted in humans were included, and 43 studies reported outcomes of hypothermic machine perfusion (HMP), with a DGF rate of 26.4%. A meta-analysis of 16 studies showed significantly lower DGF rates in the HMP group compared to those of static cold storage (SCS). Five studies reported outcomes of hypothermic machine perfusion + O2, with an overall DGF rate of 29.7%. Two studies explored normothermic machine perfusion (NMP). These were pilot studies, designed to assess the feasibility of this perfusion approach in the clinical setting. Six studies reported outcomes of normothermic regional perfusion (NRP). The overall incidence of DGF was 71.5%, as it was primarily used in uncontrolled DCD (Maastricht category I-II). Three studies comparing NRP to in situ cold perfusion showed a significantly lower rate of DGF with NRP. The systematic review and meta-analysis provide evidence that dynamic preservation strategies can improve outcomes following kidney transplantation. More recent approaches such as normothermic machine perfusion and hypothermic machine perfusion + O2 do show promising results but need further results from the clinical setting. This study shows that the implementation of perfusion strategies could play an important role in safely expanding the donor pool.

Early graft function defined by area under the curve serum creatinine 7 days post-transplant in a series of live donor kidney transplantation.

BACKGROUND: There is a degree of variability in early graft function that is often not highlighted in live kidney donor transplantation. We used the calculation of area under the curve of serum creatinine (AUC Cr) in the first 7 d post-transplant to assess early graft function and examine the influence on longer term outcome. METHODS: A total of 188 live donor renal transplants performed between 1998 and 2007 were analyzed. AUC Cr was calculated over the first 7 d post-transplant and 12 mo serum creatinine levels recorded. Donor and recipient demographics were recorded, and univariable and multivariable analyses were used to determine influencing factors. The sensitivity and specificity of AUC Cr for the detection of reduced serum creatinine at 12 mo (cut-off 130 µmol/L) were assessed by the receiver operating characteristic (ROC) curve. RESULTS: There was a significant variation in levels of AUC Cr over the first 7 d post-transplant (range, 692-5765 µmol/L.d). The ROC curve had a relatively low predictive value for the AUC Cr calculation (AUC=0.735). However, multivariable analysis showed that higher levels of AUC Cr were associated with higher serum creatinine levels at 12 mo (slope 0.012; P=0.0005). The need for dialysis, lower kidney weight, and higher recipient weight were significant independent predictors of a higher serum creatinine at 12 mo. CONCLUSION: The calculation of AUC serum creatinine 7 d post-transplant highlighted the significant variation in early graft function following live donor transplantation and was associated with creatinine levels at 12 mo. This calculation may be used as a simple prognostic marker to highlight poorer graft outcome.

A pilot study assessing the feasibility of a short period of normothermic preservation in an experimental model of non heart beating donor kidneys.

BACKGROUND: Restoring metabolism to an organ after hypothermic storage and before transplantation could reverse some of the detrimental effects of ischemic injury. This may be particularly beneficial for kidneys from non-heart-beating (NHBD) donors that sustain significant periods of warm and cold ischemic injury. This pilot study assessed the feasibility of a short period of normothermic preservation (NP) in a porcine autotransplant model. METHODS: Kidneys were subjected to 30 min of warm ischemia, then preserved by hypothermic machine perfusion (HMP) for 22 h or 20 h HMP followed by 2 h of NP using autologous blood. Kidneys were then re-implanted, a contralateral nephrectomy performed, and renal function measured over 10 d. RESULTS: Post-transplant, 4/6 animals survived in the NP group compared with 5/6 in the HMP group (P = 1.00). Creatinine levels fell below 250 µmol/L in all four of the surviving animals in the NP group compared with 2/5 in the HMP group (P = 0.608). There was no difference in levels of renal function (peak creatinine, HMP = 1736 ± 866 versus NP = 1553 ± 516 µmol/L; P ≥ 0.990). Levels of lipid peroxidation were significantly lower 60 min post-transplant in the NP group (NP = 477 ± 118.0 versus HMP = 671 ± 99.4 pg/mL; P = 0.026). CONCLUSION: A period of NP at the end of the renal preservation period in NHB kidneys is a feasible method of kidney preservation. NP could prove to be a useful technique to predetermine graft function and allow pre-transplant modification of organs.

Use of an action-selection framework for human-carnivore conflict in the Bangladesh Sundarbans.

Human-carnivore conflict is manifested in the death of humans, livestock, and carnivores. The resulting negative local attitudes and retribution killings imperil the future of many endangered carnivores. We tailored existing management tools to create a framework to facilitate the selection of actions to alleviate human-carnivore conflict and applied the framework to the human-tiger conflict in the Bangladesh Sundarbans. We identified potential actions that consider previous management efforts, local knowledge, cost-effectiveness, fieldwork experience of authors and project staff, previous research on tiger ecology by the authors, and recommendations from human-carnivore conflict studies in other countries. Our framework includes creation of a profile to improve understanding of the nature of the conflict and its underlying causality. Identified actions include deterrents, education, direct tiger management, and response teams. We ranked actions by their potential to reduce conflict and the monetary cost of their implementation. We ranked tiger-response teams and monitoring problem tigers as the two best actions because both had relatively high impact and cost-effectiveness. We believe this framework could be used under a wide range of human-wildlife conflict situations because it provides a structured approach to selection of mitigating actions.

The performance of three estimates of glomerular filtration rate before and after live donor nephrectomy.

Serum creatinine-based estimates of glomerular filtration rate (GFR) are inaccurate in healthy individuals. Therefore, their use in assessment prior to live donor nephrectomy has been restricted. There are less data on their use postdonor nephrectomy. This study assessed three GFR estimates against Cr(51) EDTA radioisotope GFR (iGFR) in the same cohort of patients before and after donor nephrectomy. A total of 206 patients underwent iGFR measurement prior to donor nephrectomy and this was repeated in 187 patients 6-8 weeks postsurgery. The iGFR was compared with the modification of diet in renal disease (eGFR), Cockcroft-Gault (cgGFR) and Mayo Clinic equation (mcGFR) estimates of GFR. Preoperatively, all GFR estimates performed poorly against iGFR; however, mcGFR provided the most reliable estimate. The eGFR underestimated iGFR by 23.60 +/- 16.43 ml/min/1.73 m(2), cgGFR by 15.54 +/- 18.13 ml/min/1.73 m(2) and mcGFR overestimated by 0.72 +/- 18.11 ml/min/1.73 m(2). Postdonation, all estimates again performed poorly, but eGFR and mcGFR outperformed cgGFR. The eGFR underestimated iGFR by 9.13 +/- 10.11 ml/min/1.73 m(2), mcGFR by 9.44 +/- 13.80 ml/min/1.73 m(2) and cgGFR overestimated by 6.42 +/- 14.49 ml/min/1.73 m(2). No GFR estimate performed sufficiently well to supersede iGFR measurement prior to donor nephrectomy. Performance postdonation was little better. In addition, there was no correlation between fall in iGFR and fall in GFR estimates postdonation.

The great saphenous vein for central venous access and haemodialysis.

BACKGROUND: Utilising an open surgical technique the Great Saphenous vein in the proximal thigh can be used for the insertion of central venous catheters for haemodialysis. This approach is safe and efficacious, and may be performed under local or general anaesthesia. This technique is of particular importance in patients requiring vascular access for haemodialysis in whom the upper central veins are stenosed and the femoral vessels are not amenable to percutaneous cannulation. METHODS: The Great saphenous vein is exposed via a surgical incision in the thigh. The central venous catheter is then inserted and advanced until in the desired position, as confirmed on fluoroscopy. RESULTS: Seven Great saphenous catheters were placed over a period of six months. All catheters insertions were technical successes with completion of at least one dialysis session. Primary patency rates were 57%, 49%, 23% at 30, 60 and 90 days respectively. CONCLUSION: The great saphenous vein offers an additional site for the insertion of central venous catheters. These data demonstrate equivalence in patency between this novel technique and percutaneous femoral vein cannulation.

Simultaneous Intestinal and Kidney Transplantation in Adults.

Aim of the study: Intestinal transplantation (IT) is a life-saving procedure for carefully selected patients with intestinal failure. We evaluated patients who had undergone simultaneous intestinal and kidney transplantation (SIKT) to determine whether UK guidelines for inclusion of a renal allograft (dialysis dependent or estimated glomerular filtration rate ((eGFR)) < 45 ml/min/1.73 m2) are justified. Methods: A single centre analysis was undertaken of adults undergoing IT at the Cambridge Transplant Centre between December 2007 and January 2016. A prospectively maintained database was used to identify SIKT recipients and determine outcomes. Results: Over this period, 63 intestinal transplants were performed. Seven (11.1%) recipients received a SIKT. Five were pre-dialysis (median eGFR 29 ml/min/1.73 m2, range 16-36 ml/min/1.73 m2). One recipient was on dialysis, and one needed bilateral nephrectomy at transplant. There were no primary kidney allograft failures and at three months, the median eGFR (55 ml/min/1.73 m2 range 39-124) was similar to recipients of IT alone (median eGFR 56 ml/min/1.73 m2 range 17-143 ml/min/1.73 m2). Two recipients required dialysis due to sepsis related kidney injury and died from multi-organ failure (20 and 63 months). Two died with a functioning renal transplant (10 and 15 months). The remaining three patients are alive at follow up (12-96 months) with an eGFR of 20-45 ml/min/1.73 m2. Conclusion: Patients with significant renal impairment (eGFR <45 ml/min/1.73 m2), and receiving dialysis may benefit from SIKT. Patient survival and renal function are broadly comparable to those undergoing IT alone. Further studies are required to justify allocation of a kidney to this complex high risk group.

Impact of Donor Hepatectomy Time During Organ Procurement in Donation After Circulatory Death Liver Transplantation: The United Kingdom Experience.

BACKGROUND: No data exist to evaluate how hepatectomy time (HT), in the context of donation after cardiac death (DCD) procurement, impacts short- and long-term outcomes after liver transplantation (LT). In this study, we analyze the impact of the time from aortic perfusion to end of hepatectomy on outcomes after DCD LT in the United Kingdom. METHODS: An analysis of 1112 DCD donor LT across all UK transplant centers between 2001 and 2015 was performed, using data from the UK Transplant Registry. Donors were all Maastricht Category III. Graft survival after transplantation was estimated using Kaplan-Meier method and logistic regression to identify risk factors for primary nonfunction (PNF) and short- and long-term graft survivals after LT. RESULTS: Incidence of PNF was 4% (40) and in multivariate analysis only cold ischemia time (CIT) longer than 8 hours (hazard ratio [HR], 2.186; 95% confidence interval [CI], 1.113-4.294; P = 0.023) and HT > 60 minutes (HR, 3.669; 95% CI, 1.363-9.873; P = 0.01) were correlated with PNF. Overall 90-day, 1-, 3-, and 5-year graft survivals in DCD LT were 91.2%, 86.5%, 80.9%, and 77.7% (compared with a donation after brain death cohort in the same period [n = 7221] 94%, 91%, 86.6%, and 82.6%, respectively [P < 0.001]). In multivariate analysis, the factors associated with graft survival were HT longer than 60 minutes, donor older than 45 years, CIT longer than 8 hours, and recipient previous abdominal surgery. CONCLUSIONS: There is a negative impact of prolonged HT on outcomes on DCD LT and although HT is 60 minutes or longer is not a contraindication for utilization, it should be part of a multifactorial assessment with established prognostic donor factors, such as age (>45 y) and CIT (>8 h) for an appropriately selected recipient.

Syntheses and quadratic nonlinear optical properties of 2,7-fluorenylene- and 1,4-phenylene-functionalized o-carboranes.

o-Carboranes C-functionalized by (4-substituted-phen-1-yl)ethynyl-1,4-phenyl groups or (2-substituted-fluoren-7-yl)ethynyl-2,7-fluorenyl groups, in which the pendant functionalization is electron-withdrawing nitro or electron-donating diphenylamino groups, have been synthesized and in many cases structurally characterized. Diphenylamino-containing examples coupled via the two π-delocalizable bridges to the electron-accepting o-carborane unit exhibit the greater quadratic optical nonlinearities at 1064 nm (hyper-Rayleigh scattering, ns pulses), the nonlinearities also increasing on proceeding from 1,4-phenylene- to 2,7-fluorenylene-containing bridge. The most NLO-efficient example 2-(n-butyl)-1-(2-((9,9-di(n-butyl)-2-(N,N-diphenylamino)-9H-fluoren-7-yl)ethynyl)-9,9-di(n-butyl)-9H-fluoren-7-yl)-1,2-ortho-carborane, consisting of diphenylamino donor, fluorenyl-containing bridge, o-carborane acceptor, and solubilizing n-butyl units, exhibits large 〈ß〉HRS (230 × 10-30 esu) and frequency-independent (two-level model) 〈ß0〉 (96 × 10-30 esu) values. Coupling two (2-((9,9-di(n-butyl)-2-(N,N-diphenylamino)-9H-fluoren-7-yl)ethynyl)-9,9-di(n-butyl)-9H-fluoren-7-yl) units to the 1,2-ortho-carborane core affords a di-C-functionalized compound with enhanced nonlinearities (309 × 10-30 esu and 129 × 10-30 esu, respectively).

Quadratic and cubic hyperpolarizabilities of nitro-phenyl/-naphthalenyl/-anthracenyl alkynyl complexes.

1-Nitronaphthalenyl-4-alkynyl and 9-nitroanthracenyl-10-alkynyl complexes [M](C[triple bond, length as m-dash]C-4-C10H6-1-NO2) ([M] = trans-[RuCl(dppe)2] (6b), trans-[RuCl(dppm)2] (7b), Ru(PPh3)2(η5-C5H5) (8b), Ni(PPh3)(η5-C5H5) (9b), Au(PPh3) (10b)) and [M](C[triple bond, length as m-dash]C-10-C14H8-9-NO2) ([M] = trans-[RuCl(dppe)2] (6c), trans-[RuCl(dppm)2] (7c), Ru(PPh3)2(η5-C5H5) (8c), Ni(PPh3)(η5-C5H5) (9c), Au(PPh3) (10c)) were synthesized and their identities were confirmed by single-crystal X-ray diffraction studies. Electrochemical studies and a comparison to the 1-nitrophenyl-4-alkynyl analogues [M](C[triple bond, length as m-dash]C-4-C6H4-1-NO2) ([M] = trans-[RuCl(dppe)2] (6a), trans-[RuCl(dppm)2] (7a), Ru(PPh3)2(η5-C5H5) (8a), Ni(PPh3)(η5-C5H5) (9a), Au(PPh3) (10a)) reveal a decrease in oxidation potential for ruthenium and nickel complexes on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. HOMO → LUMO transitions characteristic of MC[triple bond, length as m-dash]C-1-C6H4 to 4-C6H4-1-NO2 charge transfer red-shift and gain in intensity on proceeding to the ruthenium complexes; the low-energy transitions have increasing ILCT character on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. Spectroelectrochemical studies of the Ru-containing complexes reveal the appearance of low-energy bands corresponding to chloro-to-RuIII charge transfer that red-shift on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. Second-order nonlinear optical (NLO) studies at 1064 nm employing ns pulses and the hyper-Rayleigh scattering technique reveal an increase in quadratic optical nonlinearity upon introduction of metal to the precursor alkyne to afford alkynyl complexes and on proceeding from ligated-gold to -nickel and then to -ruthenium for a fixed alkynyl ligand. Quadratic NLO data of the gold complexes optically transparent at the second-harmonic wavelength reveal an increase in ßHRS on proceeding from the phenyl- to the naphthalenyl-containing complex. Broad spectral range third-order nonlinear optical studies employing fs pulses and the Z-scan technique reveal an increase in two-photon absorption cross-section on replacing ligated-gold by -nickel and then -ruthenium for a fixed alkynyl ligand. Computational studies undertaken using time-dependent density functional theory have been employed to assign the nature of the key optical transitions and suggest that the significant optical nonlinearities observed for the ruthenium-containing complexes correlate with the low-energy formally Ru → NO2 band which possesses strong MLCT character, while the more moderate nonlinearities of the gold complexes correlate with a band higher in energy that is primarily ILCT in character.

Synthesis, characterization and third-order nonlinear optical properties of a dodecaruthenium organometallic dendrimer with a zinc(ii) tetraphenylporphyrin core.

A new Zn(ii) porphyrin-based dendrimer (52) containing twelve Ru(ii) alkynyl fragments, has been prepared following a convergent approach in two steps from 5,10,15,20-tetra(4-ethynylphenyl)porphyrinatozinc(ii) (6). The cubic nonlinear optical (NLO) properties of 52 and other derivatives of 6 have been measured by third-harmonic generation (THG) at 1907 nm and by Z-scan over the spectral range 500-1700 nm, revealing the remarkable NLO response of 52 in the near-IR range. These results highlight the beneficial role of the extended "cross fourchée"-like polymetallic structure of 52 on its third-order NLO properties.

Exceptionally large two- and three-photon absorption cross-sections by OPV organometalation.

Oligo(p-phenylenevinylene)s (OPVs) containing up to 8 PV units and end-functionalized by ruthenium alkynyl groups have been prepared and their nonlinear absorption properties assessed using the Z-scan technique and employing low repetition rate femtosecond pulses. Exceptionally large two-photon absorption (ca. 12 500 GM at 725 nm) and three-photon absorption cross sections (ca. 1.6 × 10(-76) cm(6) s(2) at 1100 nm) are found for the 8PV-containing example, highlighting the potential of an "organometalation" approach to NLO-efficient organic materials.