Hematophagous arthropods are capable of transmitting human and animal pathogens worldwide. Vector-borne diseases account for 17% of all infectious diseases resulting in 700,000 human deaths annually. Repellents are a primary tool for reducing the impact of biting arthropods on humans and animals. N,N-Diethyl-meta-toluamide (DEET), the most effective and long-lasting repellent currently available commercially, has long been considered the gold standard in insect repellents, but with reported human health issues, particularly for infants and pregnant women. In the present study, we report fatty acids derived from coconut oil which are novel, inexpensive and highly efficacious repellant compounds. These coconut fatty acids are active against a broad array of blood-sucking arthropods including biting flies, ticks, bed bugs and mosquitoes. The medium-chain length fatty acids from C8:0 to C12:0 were found to exhibit the predominant repellent activity. In laboratory bioassays, these fatty acids repelled biting flies and bed bugs for two weeks after application, and ticks for one week. Repellency was stronger and with longer residual activity than that of DEET. In addition, repellency was also found against mosquitoes. An aqueous starch-based formulation containing natural coconut fatty acids was also prepared and shown to protect pastured cattle from biting flies up to 96-hours in the hot summer, which, to our knowledge, is the longest protection provided by a natural repellent product studied to date.

Abstract. Stable flies (Stomoxys calcitrans [Diptera: Muscidae] L.) are blood-feeding synanthropic pests, which cause significant economic losses in livestock. Stable fly antennae contain olfactory sensilla responsive to host and host environment-associated odours. Field observation indicated that the abundance of stable flies increased significantly in grasslands or crop fields when cattle manure slurry was applied. Major volatile compounds emanating from manure slurry were collected and identified. Behavioural responses of stable flies to those compounds were investigated in laboratory bioassays and field-trapping studies. Results from olfactometer assays revealed that phenol, p-cresol and m-cresol were attractive to adult stable flies. When tested individually, attraction was higher with lower dosages. Stable flies were most attracted to blends of phenol and m-cresol or p-cresol. Traps with binary blend lures caught more stable flies in field trials as well.

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The Li-C-Rh, bimetallic, phosphinimine spirocyclic, bridged carbene complex 1 was readily prepared from dilithiobis(diphenylphosphoranosilylimido)methandiide, [Li 2 L] 2 , and an equimolar (Rh/Li, 1:1) amount of [Rh(cod)Cl] 2 . Subsequent reaction with a different metal precursor, in the present cases, [Pd(allyl)Cl] 2 , yielded the spirocyclic Rh-Pd heterobimetallic 2 or, if a second equivalent of [Rh(cod)Cl] 2 was used, the spirocyclic Rh-Rh homobimetallic 3 was obtained; thus the system presents an effective synthetic route for the preparation of homo-or heterobimetallic complexes. All of the complexes have constrained symmetry, which creates in some cases isomeric and enantiomeric structures. The Li-Rh complex 1 thermally rearranged to the chelated, orthometalated, Rh complex 6, wherein the Rh(I) center is bound to the ipso carbon of a phenyl ring and a methine carbon formed from protonation of the spiro carbon. Remarkably, controlled hydrolysis of 6 reversed the orthometalation and provided an iminophosphorane-methine chelate complex of Rh(I), 7. Reactions of the cod-substituted complexes 2, 3, and 7 with CO resulted in the replacement of cod substituents to form parallel Rh carbonyl complexes (4, 5, and 8). The allyl substituents in the system were not affected. The carbonyl complexes 5 and 8 could be made independently from [Rh(CO) 2 Cl] 2 and either the dilithium methandiide or the methine form of the ligand as appropriate. Complexes 2-7 have been structurally characterized herein. Complexes 3 and 5 are chiral (because they lack rotation-reflection axes), but the products here are unresolved racemic mixtures according their NMR spectra. The complex 2 and its derivative 4 exist as unequal diastereomeric pairs according to the NMR. Fluxional NMR behavior is observed for 1, wherein the cod appears to partly dissociate and invert, for 2 and 3 where the cod exchange appears to involve a different mechanism being assisted by dissociation of one imine substituent, for 2 and 4 wherein allyl syn-syn, anti-anti exchange occurs between the diastereomers, and for 7 wherein the coordinated and uncoordinated imine groups exchange.