No abstract

No abstract

1. Sympetrum fonscolombii dragonflies are believed to migrate seasonally. In the spring and early summer, the already-mature dragonflies arrive in Middle Asia for reproduction. In the late summer and autumn, summer-generation dragonflies migrate to the south. Their wintering places remain unknown. 2. Stable hydrogen (δ 2 H) and oxygen (δ 18 O) isotope analyses were conducted to confirm the migration of S. fonscolombii and determine the wintering area. Stable isotope composition of carbon (δ 13 C) and nitrogen (δ 15 N) in wings and legs was used to clarify the habitats in which dragonfly development took place. 3. Three cohorts of dragonflies collected in different regions of Middle Asia were used for analysis: (i) immigrants that arrived in the spring, (ii) residents that developed in Middle Asia, and (iii) transit dragonflies migrating to the south during autumn. 4. The average δ 2 H values in the wings were significantly higher in immigrants (−96‰) than in residents (−134‰) and transit individuals (−124‰). High δ 18 O and δ 15 N values in the tissue of immigrants confirmed their southerly origin. 5. Based on the species range and the global distribution of annual averages of δ 2 H and δ 18 O values in precipitation, the latitudinal migrations of S. fonscolombii were inferred to cover the area from the proposed natal regions of immigrants in SouthWest Asia (below ∼36 ∘ N) to Southern Ural and the south of Western Siberia in the north (54-55 ∘ N) with a maximum migration distance of more than 4000 km.

The reaction of the 1,2,3,5-dithiadiazolyls (4-R-C(6)H(4)CN(2)S(2))(2) (R = Me, 2a; Cl, 2b; OMe, 2c; and CF3, 2d) and (3-NC-5-tBu-C(6)H(3)CN(2)S(2))(2) (2e) with [CpCr(CO)(3)](2) (Cp = eta(5)-C(5)H(5)) (1) at ambient temperature respectively yielded the complexes CpCr(CO)(2)(eta(2)-S(2)N(2)CC(6)H(4)R) (R = 4-Me, 3a; 4-Cl, 3b; 4-OMe, 3c; and 4-CF(3), 3d) and CpCr(CO)(2)(eta(2)-S(2)N(2)CC(6)H(3)-3-(CN)-5-(tBu)) (3e) in 35-72% yields. The complexes 3c and 3d were also synthesized via a salt metathesis method from the reaction of NaCpCr(CO)(3) (1B) and the 1,2,3,5-dithiadiazolium chlorides 4-R-C(60H(4)CN(2)S(2)Cl (R = OMe, 8c; CF(3), 8d) with much lower yields of 6 and 20%, respectively. The complexes were characterized spectroscopically and also by single-crystal X-ray diffraction analysis. Cyclic voltammetry experiments were conducted on 3a-e, EPR spectra were obtained of one-electron-reduced forms of 3a-e, and variable temperature 1H NMR studies were carried out on complex 3d. Hybrid DFT calculations were performed on the model system [CpCr(CO)(2)S(2)N(2)CH] and comparisons are made with the reported CpCr(CO)(2)(pi-allyl) complexes.