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Refluxing Mo(CO)6 in the presence of the phosphine-functionalized α-diimine ligand Ph2PPrDI allowed for substitution and formation of the dicarbonyl complex, (Ph2PPrDI)Mo(CO)2. Oxidation with I2 followed by heating resulted in further CO dissociation and isolation of the corresponding diiodide complex, (Ph2PPrDI)MoI2. Reduction of this complex under a N2 atmosphere afforded the corresponding bis(dinitrogen) complex, (Ph2PPrDI)Mo(N2)2. The solid-state structures of all three compounds were found to feature a tetradentate chelate and cis-monodentate ligands. Notably, the addition of CO2 to (Ph2PPrDI)Mo(N2)2 is proposed to result in head-to-tail CO2 coupling to generate the corresponding metallacycle and ultimately a mixture of (Ph2PPrDI)Mo(CO)2 and the bis(oxo) dimer, [(κ3-Ph2PPrDI)Mo(O)(μ-O)]2. Computational studies have been performed to gain insight into the reaction and evaluate the importance of cis-coordination sites for selective head-to-tail CO2 reductive coupling, CO deinsertion, disproportionation, and stepwise CO2 deinsertion.

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N,N-Diborylamines have emerged as promising reagents in organic synthesis; however, their efficient preparation and full synthetic utility have yet to be realized. To address both shortcomings, an effective catalyst for nitrile dihydroboration was sought. Heating CoCl2 in the presence of PyEtPDI afforded the six-coordinate Co(II) salt, [(PyEtPDI)CoCl][Cl]. Upon adding 2 equiv of NaEt3BH, hydride transfer to one chelate imine functionality was observed, resulting in the formation of (κ4-N,N,N,N-PyEtIPCHMeNEtPy)Co. Single-crystal X-ray diffraction and density functional theory calculations revealed that this compound possesses a low-spin Co(II) ground state featuring antiferromagnetic coupling to a singly reduced imino(pyridine) moiety. Importantly, (κ4-N,N,N,N-PyEtIPCHMeNEtPy)Co was found to catalyze the dihydroboration of nitriles using HBPin with turnover frequencies of up to 380 h-1 at ambient temperature. Stoichiometric addition experiments revealed that HBPin adds across the Co-Namide bond to generate a hydride intermediate that can react with additional HBPin or nitriles. Computational evaluation of the reaction coordinate revealed that the B-H addition and nitrile insertion steps occur on the antiferromagnetically coupled triplet spin manifold. Interestingly, formation of the borylimine intermediate was found to occur following BPin transfer from the borylated chelate arm to regenerate (κ4-N,N,N,N-PyEtIPCHMeNEtPy)Co. Borylimine reduction is in turn facile and follows the same ligand-assisted borylation pathway. The independent hydroboration of alkyl and aryl imines was also demonstrated at 25 °C. With a series of N,N-diborylamines in hand, their addition to carboxylic acids allowed for the direct synthesis of amides at 120 °C, without the need for an exogenous coupling reagent.

This community forestry case study examines village forest councils (van panchayat) in India’s northern state of Uttarakhand. We describe forest stocking levels of 20 community forests and address the question of whether these forests are in a position to provide commodity resources, such as fuelwood and fodder, on a sustainable basis. In addition, we report on the perceptions of the villagers on whether their respective community forest is meeting their fuelwood and fodder needs. At the biophysical level, none of the community forests were in a position to provide fuelwood and fodder on a sustainable basis. Most forests did not have adequate overstory stocking, and there was no evidence of deliberate management to improve the situation. Interviews with 400 villagers (20 in each village) supported the field findings. Villagers unanimously reported that their respective community forest was inadequate in supplying commodity needs. Furthermore, they wished the Forest Department would provide more technical and financial assistance to guide them with forest management needs. Women are a critical part of community forestry as they are the primary gatherers of fuelwood and fodder. Although the perceptions of women toward forest management issues are important, our interviews with female villagers indicate they play a passive role in decision-making. Decentralization in natural resources management sounds good at the theoretical level as it provides villagers with some authority and autonomy, but it cannot be effectively implemented without professional guidance coupled with resources. The villagers are ready and willing to improve the situation, but they do not have the resources to make change unilaterally—they need professional and financial support from the Forest Department.

The formally zero-valent Mn dimer [(Ph2PEtPDI)Mn]2 has been synthesized upon reducing (Ph2PEtPDI)MnCl2 with excess Na/Hg. Single crystal X-ray diffraction analysis has revealed that [(Ph2PEtPDI)Mn]2 possesses a κ4-PDI chelate about each Mn center, as well as η2-imine coordination across the dimer. The chelate metrical parameters suggest single electron PDI reduction and EPR spectroscopic analysis afforded a signal consistent with two weakly interacting S = 1/2 Mn centers. At ambient temperature in the absence of solvent, [(Ph2PEtPDI)Mn]2 has been found to catalyze the hydrosilylation of aldehydes at loadings as low as 0.005 mol % (0.01 mol % relative to Mn) with a maximum turnover frequency of 9,900 min–1 (4,950 min–1 per Mn). Moreover, the [(Ph2PEtPDI)Mn]2-catalyzed dihydrosilylation of formates has been found to proceed with turnover frequencies of up to 330 min–1 (165 min–1 relative to Mn). These metrics are comparable to those described for the leading Mn catalyst for this transformation, the propylen...

Reduction of 6-coordinate ((Ph2PPr)DI)FeBr₂ under N2 results in formation of the terminal dinitrogen complex, ((Ph2PPr)DI)FeN2. Heating this product to 75 °C allows for C-H and C-P activation of the chelate to generate the cisoid and transoid isomers of [(μ-PrPPh-κ(5)-P,N,N,Cγ,P-(Ph2PPr)DI(PrPPh))Fe]2. Mechanistic possibilities for this transformation are discussed.

Heating (THF)2MnCl2 in the presence of the pyridine-substituted bis(imino)pyridine ligand, (PyEt)PDI, allowed preparation of the respective dihalide complex, ((PyEt)PDI)MnCl2. Reduction of this precursor using excess Na/Hg resulted in deprotonation of the chelate methyl groups to yield the bis(enamide)tris(pyridine)-supported product, (κ(5)-N,N,N,N,N-(PyEt)PDEA)Mn. This complex was characterized by single-crystal X-ray diffraction and found to possess an intermediate-spin (S = (3)/2) Mn(II) center by the Evans method and electron paramagnetic resonance spectroscopy. Furthermore, (κ(5)-N,N,N,N,N-(PyEt)PDEA)Mn was determined to be an effective precatalyst for the hydrosilylation of aldehydes and ketones, exhibiting turnover frequencies of up to 2475 min(-1) when employed under solvent-free conditions. This optimization allowed for isolation of the respective alcohols and, in two cases, the partially reacted silyl ethers, PhSiH(OR)2 [R = Cy and CH(Me)((n)Bu)]. The aldehyde hydrosilylation activity observed for (κ(5)-N,N,N,N,N-(PyEt)PDEA)Mn renders it one of the most efficient first-row transition metal catalysts for this transformation reported to date.

Introduction: The rates of atypia of undetermined significance (AUS) by fine-needle aspiration (FNA) and malignant outcomes have been estimated at < 7% and 5–15%, respectively. Initial AUS diagnosis is followed up clinically with serial ultrasounds, repeat FNA, molecular testing, or direct surgery. We investigated the incidence, follow-up modalities, and final outcomes of AUS in Newfoundland. Methods: All cases of AUS diagnosed at the Eastern Health Cytology Laboratory between 1 January 2010 and 31 December 2013 were identified. Electronic medical records were examined for follow-up modalities and final histologic diagnosis. The final outcomes were reported as benign, malignant, or undetermined. Results: Out of 3,285 thyroid FNAs, 181 (5.5%) were AUS. Fifty-seven (31.5%) had repeat FNA diagnosed as benign (38.6%), AUS (29.8%), or suspicious/malignant (8.8%). Eighty-four (46.4%) had surgery after the first AUS diagnosis, 39 (46.4%) of which were malignant. Twenty-four patients (13.3%) were followed up by serial ultrasound only, 2 (1.1%) by molecular testing, and 1 (0.6%) died of unrelated disease. Thirteen (7.2%) had no follow-up record. Our malignancy rate (MR) was 29.8%. Conclusion: The MR in our population was higher than the rate proposed by The Bethesda System for Reporting Thyroid Cytopathology. Repeat FNA can reduce the rate of unnecessary surgeries, but practice guidelines should consider individual and institutional circumstances. The ratio MR:ADR (AUS diagnostic rate) may be a better indicator of performance.