The Barbados (Alias Folkestone) Marine Reserve, Barbados: A Late Bloomer?

The Barbados Marine Reserve (BMR) is a 2.2 km2 no-take marine reserve occupying one of the most intensely used and impacted sections of the coast and comprises four zones: Scientific, Northern Watersports, Recreational, Southern Watersports. Establishment of the BMR in 1981 did little to change the de facto marine resource governance regime for the area. There was minimal consultation of stakeholders in determining the zoning and regulations. Fishers were negatively impacted, and no user group derived significant benefits from the reserve. A mandate to maximise revenues led the National Conservation Commission (NCC), responsible for BMR management, to virtually abandon the reserve. Efforts to spur institutional change were not effective, because of the centralized authority of the NCC and the belief that the BMR could not generate revenue. In 1998, the Government initiated a study to reform marine resource governance within the BMR and adjacent areas. Stakeholder consultation revealed complex patterns of use in the area. Recommendations, adopted by the Government in March, 2001 included establishing a broader Marine Protected Area (MPA) along an expanded coastline (from 2.6 km to 9.5 km) with seven types of management zones, and renaming the area as the Folkestone Marine Managed Area. Also proposed was a Marine Management Area Authority, within the Ministry of the Environment’s Coastal Zone Management Unit, to designate and manage MPA’s

Triboranate Derivatives of Calcium and Strontium

This contribution reports the alkaline earth-mediated formation of homonuclear sigma bonding between the metalloid element, boron. The resultant triborane anions result from the formal dismutation of bis(pinacolato)diboron (B2pin2) and the generation of putative heavier group 2 boryl intermediates. Initial reactions of the heavier alkaline earth bis-(trimethylsilyl)amides, [Ae{N(SiMe3¬)2}2] (Ae = Ca or Sr), with an equimolar quantity of bis(pinacolato)diboron (B2pin) provided the 4-coordinate group 2 silazide diborane adducts [Ae(B2pin2){N(SiMe3¬)2}2] in which the diborane acts as a bidentate ligand via 2-O,O' coordination. Reaction of the calcium species at 60 C with a further three molar equivalents of B2pin2 induced the elimination of pinBN(SiMe¬3)2 and the formation of the bis-triboranate derivative, [Ca(B3pin3)2], in which the 6-coordinate calcium centre is bound in a 3-O,O',O''-coordination mode ¬by the three contiguous pinacolate oxygen atoms of both catena-B(sp2)-B(sp3)-B(sp2) bonded anions. Although analogous treatment of [Ae(B2pin2){N(SiMe3¬)2}2] provided similar triboranate anion formation, in this case two equivalents of the strontium silazide were retained within the structure of the trimetallic species, [Sr(B3pin3)2(Sr{N(SiMe3)2}2)2]. Despite these contrasting outcomes both triboranate complexes provide rare examples of catena-boron species beyond the common diboranes, (R2¬B-BR2), in which the homologated unit is propagated by electron precise and otherwise unsupported B-B bonds

Transforming PPh3 into Bidentate Phosphine Ligands at Ru-Zn Heterobimetallic Complexes

The reaction of [Ru(PPh 3) 3Cl 2] with excess ZnMe 2 led to P-C/C-H bond activation and P-C/C-C bond formation to generate a chelating diphenylphosphinobenzene ligand as well as a cyclometallated (diphenylphosphino)biphenyl group in the final product of the reaction, [Ru(dppbz)(PPh 2(biphenyl)′)(ZnMe)] (1; dppbz = 1,2-bis(diphenylphosphino)benzene); PPh 2(biphenyl)′ = cyclometallated PPh 2(biphenyl). The mechanism of reaction was studied and C-C coupling to give a bidentate 2,2′-bis(diphenylphosphino)biphenyl (BIPHEP) ligand was suggested to be one of the key steps of the process. This was confirmed by the reaction of [Ru(BIPHEP)(PPh 3)HCl] with ZnMe 2, which also gave 1. An analogous set of steps took place upon addition of ZnMe 2 to [Ru(rac-BINAP)(PPh 3)HCl] (rac-BINAP = racemic(2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) to give [Ru(dppbz)(PPh 2(binaphthyl)′)ZnMe] (3). H 2 and the C-H bond of PhCCH added across the Ru-Zn bond of 1, and also reversed the phosphine cyclometallation, to give [Ru(dppbz)(Ph 2P(biphenyl))(H) 2(H)(ZnMe)] (4) and [Ru(dppbz)(Ph 2P(biphenyl))(CCPh) 2(H)(ZnMe)] (5) respectively. </p

Multimetallic Alkaline-Earth Hydride Cations

Reactions of dimeric β-diketiminato (BDI) magnesium and calcium hydrides with [(BDI)Mg]+[Al{OC(CF3)3}4]- provide ionic multimetallic hydride derivatives, which have been characterized by single-crystal X-ray diffraction analysis. The exclusively magnesium centered species comprises a cation in which two [(BDI)Mg]+ units are connected by a single μ2-bridging hydride. In contrast, the greater lability of the calcium-containing system is underscored by the isolation of a cyclic heterotrimetallic species in which a CaH2 moiety is coordinated by a molecule of benzene and an aryl substituent of a [{(BDI)Mg}2H]+ cation. The homometallic dimagnesium species displays a greater facility toward reaction with diphenylacetylene than neutral [(BDI)MgH]2, although the resultant crystallographically characterized vinyldimagnesium cation equilibrates into a complex mixture of neutral and ionic species in solution. An initial assessment of both systems for the hydrosilylation of 1-hexene and diphenylacetylene evidences an inferior catalytic performance of [(BDI)MgH]2 in isolation.</p

(carbene)CuF Complexes Featuring Bulky Arduengo-Type, Ring-Expanded, and Cyclic (Alkyl)(amino)carbenes:Applications in Catalytic Aldehyde Allylation

Five examples of two-coordinate copper(I) fluoride complexes stabilized by five-, six-, and seven-membered-ring N-heterocyclic carbenes or a cyclic (alkyl)(amino)carbene have been prepared, structurally characterized, and employed in the catalytic allylation of octanal. The very bulky trityl-based carbene ITr affords the most active catalytic system. Mechanistic studies have led to the isolation of (ITr)Cu(CH2CHCH2) and [{(6-Mes)Cu}2(μ-OEt)][SiF5], which along with the fluorosilane (EtO)3SiF are of relevance to the catalytic cycle

Defending Norway and the Northern Flank: analysis of NATO's strategic options

The purpose of this thesis was to determine an appropriate strategy for the defense of NATO's Northern Flank. If NATO fails to successfully defend this Flank, its vital North Atlantic SLOCS will be severly threatened and the rear of the Central Front will be exposed to attack from the sea. Norway's strategic location makes it the key to the defense of the region. Deterrence, the defense of Norway, and the protection of the Atlantic SLOCS are the fundamental goals of NATO in the region. Under current conditions NATO must meet two basic objectives to achieve these goals--the Alliance must provide reinforcements to Norway very early in a crisis and it must control the Norwegian Sea to maintain the war effort after the outbreak of hostilities. Four strategic options were considered in this analysis: expansion of deterrence, increased prepositioning, a defensive barrier, and forward defense. Of the four strategies, forward defense is recommended because it is the only strategy that adequately addresses the basic objectiveshttp://archive.org/details/defendingnorwayn00mahoLieutenant, United States NavyApproved for public release; distribution is unlimited

Dehydrohalogenation of halobenzenes and C(sp3)-X (X = F, OPh) bond activation by a molecular calcium hydride

International audienceThe molecular calcium hydride, [(BDI)CaF](2) (BDI = HC{(Me)CN-2,6-i-Pr2C6H3}(2)), effects the slow hydrodehalogenation of C6H5X (X = I, Br) to provide benzene and the respective dimeric calcium halides, [(BDI)CaX](2). Although a similar reaction with fluorobenzene was non-discriminating, the analogous hydrogenation of chlorobenzene was observed, albeit this process yields the calcium hydride-chloride as the alkaline earth-containing product. Assessment of the bromide- and chloride-based processes by density functional theory (DFT) calculations, imply that the reactions take place with the retention of the dimeric calcium structures throughout. Both systems invoke an S N Ar-type displacement of the halide, via barriers (in the range 32-34 kcal mol(-1) for C6H5Br and 31.1-32.9 kcal mol(-1) for C6H5Cl), which vary only marginally during the transformation of the initial hydride and halide-hydride intermediates. The isolation of the calcium hydride-chloride is ascribed, therefore, to its more rapid crystallisation and depletion from solution. Also reported is the reactivity of [(BDI)CaH](2) with alpha,alpha,alpha-trifluorotoluene and anisole, which yield the corresponding dicalcium hydride-fluoride and phenoxide derivatives, respectively, rather than the products of directed ortho metalation. (C) 2021 Elsevier Ltd. All rights reserved