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Low-carbon economy is an emerging and inevitable pathway toward sustainable development of cold chain logistics. Low-temperature transportation is the crucial link of cold chain logistics to low-carbon economy and the industry is known to have the higher energy consumption. Prior studies are lacking in involving the carbon emission cost in the optimization process. Route optimization of low-temperature transportation is conducive to the low-carbon cold chain logistics. This study aims to introduce the low-carbon economy into the cold chain logistics. There are various costs needed to be considered in cold chain logistics, and a cold chain logistics route optimization model included the carbon emission cost was developed. Ribonucleic acid computing was combined with ant colony optimization to prevent the influence of unreasonable parameter selection on algorithm performance. This novel proposed approach was applied to solve the route optimization problem of a cold chain logistics firm located in the Xiong'an, China. The results showed this method reduced the overall cost of logistics and minimized the amount of carbon emissions. The finding shed the light on the low-carbon transformational development of cold chain logistics firms.

The Zn(II) complexes of two bipyridyl derivatives with trimethylaminomethyl groups, [Zn(L 1 ) 3 ](ZnBr 4 )(ClO 4 ) 2 Br 4 · 12H 2 O ( 1 ) and [Zn(L 2 ) 3 ](ClO 4 ) 8 · H 2 O ( 2 ) (L 1 = [4,4′-(Me 3 NCH 2 ) 2 -bpy] 2+ , L 2 = [5,5′-(Me 3 NCH 2 ) 2 -bpy] 2+ and bpy = 2,2′-bipyridyl), were synthesized and characterized. The structure of complex 1 has been determined by X-ray diffraction, and the configuration of ligand-coordinated Zn(II) ion can be well described as distorted octahedral. Species distribution of both complexes in aqueous solution was investigated by potentiometeric titration. DNA-binding ability of both complexes was studied by UV spectroscopy titration. Under hydrolytic condition, both complexes (150 μM) can effectively cleave plasmid pBR322 DNA from supercoiled to nicked form, giving hydrolysis rate constants of 2.63 × 10 −5 and 9.92 × 10 −5 s −1 , respectively (pH 7.75, 37 °C). The result shows that complex 2 is one of the most active artificial nucleases based on zinc.

Reaction of [Pt( Bu 3 t tpy )Cl]+ ( Bu 3 t tpy = 4,4′,4′′-tri-tert-butyl-2,2′:6′,2′′-terpyridine) with 5-ethynyl-2,2′-bipyridine (HC Cbpy) or 5,5′-bis(trimethylsilylethynyl)-2,2′-bipyridine (Me3SiC CbpyC CSiMe3) in the presence of cuprous iodide gives [Pt(tBu3tpy)(C Cbpy)]+ (1) or [{Pt( Bu 3 t tpy )}2(C CbpyC C)]2+ (2) through Pt-acetylide σ-coordination, respectively. Incorporating 1 or 2 with Ln(hfac)3(H2O)2 through 2,2′-bipyridyl chelating the LnIII (Ln = Nd, Eu, and Yb) centers induces formation of a series of [Pt( Bu 3 t tpy )(C Cbpy){Ln(hfac)3}]+ (PtLn) or [{Pt( Bu 3 t tpy )}2(C CbpyC C){Ln(hfac)3}]2+ (Pt2Ln) complexes, respectively. The structures of binuclear platinum(II) complex 2(PF6)2 and heterobinuclear PtNd complex 3(CF3COO) were determined by single crystal X-ray diffraction. Both 1 and 2 exhibit typical low-energy absorption bands in near UV–Vis region, ascribed to dπ(Pt) → π∗( Bu 3 t tpy ) MLCT and π(C Cbpy/C CbpyC C) → π∗( Bu 3 t tpy ) LLCT transitions. Upon formation of the PtLn or PtLn2 complexes, the low-energy absorption bands are obviously blue-shifted (15–20 nm) compared with those in the PtII precursor 1 or 2. With excitation at 350 nm Bu 3 t tpy )(acetylide) chromophore to the lanthanide(III) centers.

A series of Cu(II) complexes of disubstituted 2,2′-bipyridine bearing ammonium groups [Cu(L1−4)2Br]5+ (1–4, L1 = [5,5′-(Me2NHCH2)2-bpy]2+, L2 = [5,5′-(Me3NCH2)2-bpy]2+, L3 = [4,4′-(Me2NHCH2)2-bpy]2+, L4 = [4,4′-(Me3NCH2)2-bpy]2+ and bpy = 2,2′-bipyridyl) were synthesized, of which complexes 1 and 4 were structurally characterized. Both coordination configurations of Cu(II) ions can be described as distorted trigonal bipyramid. The interaction between all complexes and CT-DNA was evaluated by thermal-denaturation experiments and CD spectroscopy. Results show that the complexes interact with CT-DNA via outside electrostatic interactions and their binding ability follows the order: 1 > 2 > 3 > 4. In the absence of any reducing agents, the cleavage of plasmid pBR322 DNA by these complexes was investigated and the hydrolysis kinetics of DNA was studied in Tris buffer (pH 7.5) at 37 °C. Obtained pseudo-Michaelis–Menten kinetic parameters: 15.0, 13.6, 2.01 and 1.69 h−1 for 1, 2, 3 and 4, respectively, indicate that complexes 1 and 2 exhibit very high DNA cleavage activities. According to their crystal data, the high nuclease activity may be attributed to the strong interaction of the metal moiety and two ammonium groups with phosphate groups of DNA.

Incorporation of diplatinum component [Pt2(μ-dppm)2(C Cbpy)4] (1, dppm = Ph2PCH2PPh2, C Cbpy = 2,2′-dipyridyl-5-acetylide) with Re(CO)5Cl, Ru(bpy)2Cl2 (bpy = 2,2′-bipyridine) and Gd(hfac)3(H2O)2 (Hhfac = hexafluoroacetylacetone) via 2,2′-dipyridyl chelating induced isolation of Pt 2 II Re 4 I (2), Pt 2 II Ru 4 II (3), and Pt 2 II Gd 2 III (4) complexes, respectively. The structures of 2 and 4 were determined by X-ray single crystal diffraction. Intense low-energy absorptions occur in the range 360–510 nm originating from metal-to-ligand charge transfer (MLCT) transitions. These compounds display photoluminescence in both solid states and dichloromethane at room temperature with emissive lifetimes in the range of microseconds.

A series of phosphine-linked oligomers of oxo-centered triruthenium-acetate clusters have been prepared by the reaction of [Ru3O(OAc)6(py)2(CH3OH)](PF6) (1) with di- or poly-phosphine. They have been characterized by elemental analysis, ESI-MS spectrometry, UV–Vis, IR, and 31P NMR spectroscopy, and cyclic and differential pulse voltammetry. The structures of diphosphine-linked dimeric compounds 4 and 7 were determined by X-ray crystallography. As revealed by redox wave splitting, weak to moderate electronic communication is operative between triruthenium clusters across bridging di- or poly-phosphine. With increase of the methylene number in Ph2P(CH2)nPPh2, electronic communication decreases rapidly in diphosphine-linked dimeric complexes [{Ru3O(OAc)6(py)2}2{μ-Ph2P(CH2)nPPh2}]2+ (n = 1–5).

Diphosphine-bridged dimers of oxo-centered triruthenium–acetate cluster units, i.e., [{Ru 3 O(OAc) 6 (py) 2 } 2 (dppan)](PF 6 ) 2 ( 2 ) and [{Ru 3 O(OAc) 6 (py) 2 } 2 (dppf)](PF 6 ) 2 ( 3 ) were prepared by reaction of 2.3 equivalent [Ru 3 O(OAc) 6 (py) 2 (CH 3 OH)](PF 6 ) with 9,10-bis(diphenylphosphino)anthracene (dppan) or 1,1′-bis(diphenylphosphino)ferrocene (dppf), respectively. Apparent redox wave splitting is observed in complex 2 , revealing the presence of electronic communication between two triruthenium units mediated through bridging dppan. The complexes were characterized by elemental analysis, IR, UV–Vis, 31 P NMR, and ES-MS spectroscopies, and cyclic and differential-pulse voltammetry. The crystal structure of complex 3 was determined by X-ray crystallography.

A series of cyclometallated iridium(III) acetylide complexes Ir(ppy)2(PPh3)(C CR) (R = C6H5 3, C6H4But-4 4, C6F5 5, C6H4COMe-4 6, SiMe3 7) were synthesized by substitution of coordination chloride in precursor Ir(ppy)2(PPh3)Cl (2, ppy = 2-phenylpyridine) with an acetylide ligand. These complexes are brightly luminescent in fluid dichloromethane at ambient temperature, originating from 3MLCT/3LLCT/3IL states as supported by TD-DFT studies. It is demonstrated that substitution of coordination chloride in precursor 2 (λem = 456 and 485 nm, Φem = 1.6%) with an acetylide ligand results in obvious red-shift of the emission as well as significant enhancement of the luminescence efficiency in 3–7 (λem = 480–510 nm, Φem = 9.5%–19%) since the energy level of non-emissive d–d transition is highly raised and thus d–d state deactivation is significantly suppressed.

Reaction of cyclometallated iridium(III) complex Ir(ppy)2(PPh3)Cl (2, ppy = 2-phenylpyridine) with dicyanamide or tricyanomethanide gave neutral mononuclear complexes Ir(ppy)2(PPh3)N(CN)2 (3a) or Ir(ppy)2(PPh3)C(CN)3 (3b), and dicyanamide/tricyanomethanide-linked binuclear iridium(III) complexes [{Ir(ppy)2(PPh3)}2N(CN)2]+ (4a) or [{Ir(ppy)2(PPh3)}2C(CN)3]+ (4b). Substitution of coordinated chloride in the precursor 2 with dicyanamide or tricyanomethanide improved significantly the luminescence properties of 3a–4b. Compared with that in the precursor 2 (1.6%), 2.2 to 9.3-fold enhancement of emission quantum yields was detected in 3a–4b.

The preparation, characterization and photophysical properties of heterobinuclear complexes {Pt(C^N^N)(C Cbpy)}Ln(hfac)3 (C^N^N = 2-(6-(naphthalen-3-yl)-4-phenylpyridin-2-yl)pyridine; HC Cbpy = 5-ethynyl-2,2′-bipyridine; Ln = Nd, Eu, Yb; hfac = hexafluoroacetylacetonate) are described. With excitation at 390 ⩽ λex ⩽ 500 nm which is the MLCT/LLCT absorption region of the Pt(C^N^N)(C Cbpy) chromophore, lanthanide luminescence is successfully attained by Pt → Ln energy transfer from the platinum(II) antenna chromophore to the lanthanide center across the bridging C Cbpy ligand.

Octahedral hexanuclear ferrocenylacetylide complexes [Ag6(μ-dppm)2(μ3-η1-CCFc)4(CH3OH)2](BF4)2 (1) and [Cu6(μ-dppm)2(μ3-η1-CCFc)4(ClO4)2] (2) (dppm=Ph2PCH2PPh2, Fc=ferrocenyl) are synthesised and characterized structurally.

The reaction between [Cu2(Ph2PNHPPh2)2(MeCN)2](BF4)2 and sodium salt of mercaptoacetic acid (HSCH2COONa) at room temperature for 12 h produced a doubly μ3-SH-bridged tricopper complex [Cu3(μ-Ph2PNHPPh2)3(μ3-SH)2](BF4)·2MeOH·Et2O which affords a trigonal bipyramidal core of Cu3(μ3-SH)2 with copper ⋯ copper separations around 3.0 A. The complex is photoluminescent and it displays an emissive maximum at 523 nm in the solid state at 293 K.

Cadmium sulfide (CdS) nanoparticles of about 3 nm in diameter have been prepared by the sonochemical reduction of a mixed solution of cadmium chloride (CdCl2), sodium thiosulfate (Na2S2O3) and isopropyl alcohol ((CH3)2CHOH) in Ar atmosphere at room temperature. The CdS nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The formation mechanism of CdS nanoparticles is also discussed together with the optical absorption spectroscopy analysis. The method presented here can be used for the preparation of other sulfide nanoparticles.