Pengembangan Protokol Media Untuk Kultur Embrio Kelapa Kopyor (Coco Nucifera L.) Di Jawa Tlmur

Dalam USAha untuk mendapatkan kelapa Kopyor yang true-to-type, satu-satunya cara adalah dengan menginokulasikan embrio dalam media buatan pada kondisi in-vitro. Ada lima (5) protokol media dengan media dasar Y3 (Eeuwens) dan MS (Murashige & Skoog) yang dicoba yaitu M1 (Protokol UPLB/Philippines) sebagai kontrol, M2 (Protokol I) dengan rangkaian Y3 cair; Y3 cair; Y3 cair (media Y3 cair pada tahap inisiasi ; Y3 cair sub kultur I dan Y3 cair sub kultur II), M3 (Protokol II) dengan rangkaian media Y3 padat; Y3 padat; Y3 padat, ~ (Protokol III) dengan rangkaian media MS padat; MS padat; MS padat, ~ (Protokol IV) dengan rangkaian media Y3 cair; MS padat; Y3 cair, ~ (Protokol V) dengan rangkaian media MS cair; Y3 padat ;Y3 cair. Pertumbuhan embrio kelapa Kopyor sangat capat pada Protokol media II (serangkaian Y3 padat pad a tahap inisiasi, subkultur I dan II), sehingga menjadi plantlet yang sempurna. Sebaliknya pada protokol media I (serangkaian Y3 cair) embrio hanya membesar tetapi tidak dapat berkecambah. Pad a Protokol III embrio memberikan respon yang positif meskipun perkembangan embrio tidak secepat seperti pada protokol II. Pertumbuhan embrio terhenti atau mengalami stagnasi pada serangkain media protokol IV

Polymorphic Diversity: <i>N</i>‑Phenylbenzamide as a Possible Polymorphophore

In this work, we identify and describe a moiety that may be capable of encouraging the formation of polymorphs. Four new <i>N</i>-phenylbenzamide-based compounds have been synthesized yielding four pairs of polymorphs upon recrystallization. The structures of these have been discussed and compared with the previously reported polymorphs of <i>N</i>-[2-(hydroxymethyl)­phenyl]­benzamide. The results indicate that the conformation of the <i>N</i>-phenylbenzamide group is generally constant but is sometimes altered by the crystal packing. The <i>N</i>-phenylbenzamide group is capable of intermolecular N–H···O hydrogen bonding but requires a change in conformation which is generally resisted by the molecule. As a consequence, weak forces such as C–H···O, C–H···N, C–H···π, and π···π interactions play significant but varying roles in these structures. One possible reason for the varying nature of the π···π interactions may be due to the variation of the electrostatic potential across the <i>N</i>-phenylbenzamide group in which negative and positive regions alternate across the face of the molecule. It is the combination of all these attributes that possibly leads to polymorphism being observed in the structures reported here

The Synthesis of a Corrole Analogue of Aquacobalamin (Vitamin B_12a) and Its Ligand Substitution Reactions

The synthesis of a Co­(III) corrole, [10-(2-[[4-(1<i>H</i>-imidazol-1-ylmethyl)­benzoyl]­amino]­phenyl)-5,15-diphenylcorrolato]­cobalt­(III), DPTC-Co, bearing a tail motif terminating in an imidazole ligand that coordinates Co­(III), is described. The corrole therefore places Co­(III) in a similar environment to that in aquacobalamin (vitamin B_12a, H₂OCbl⁺) but with a different equatorial ligand. In coordinating solvents, DPTC-Co is a mixture of five- and six-coordinate species, with a solvent molecule occupying the axial coordination site trans to the proximal imidazole ligand. In an 80:20 MeOH/H₂O solution, allowed to age for about 1 h, the predominant species is the six-coordinate aqua species [H₂O–DPTC-Co]. It is monomeric at least up to concentrations of 60 μM. The coordinated H₂O has a p<i>K</i>_a = 9.76(6). Under the same conditions H₂OCbl⁺ has a p<i>K</i>_a = 7.40(2). Equilibrium constants for the substitution of coordinated H₂O by exogenous ligands are reported as log <i>K</i> values for neutral N-, P-, and S-donor ligands, and CN^–, NO₂^–, N₃^–, SCN^–, I^–, and Cys in 80:20 MeOH/H₂O solution at low ionic strength. The log <i>K</i> values for [H₂O–DPTC-Co] correlate reasonably well with those for H₂OCbl⁺; therefore, Co­(III) displays a similar behavior toward these ligands irrespective of whether the equatorial ligand is a corrole or a corrin. Pyridine is an exception; it is poorly coordinated by H₂OCbl⁺ because of the sterically hindered coordination site of the corrin. With few exceptions, [H₂O–DPTC-Co] has a higher affinity for neutral ligands than H₂OCbl⁺, but the converse is true for anionic ligands. Density functional theory (DFT) models (BP86/TZVP) show that the Co–ligand bonds tend to be longer in corrin than in corrole complexes, explaining the higher affinity of the latter for neutral ligands. It is argued that the residual charge at the metal center (+2 in corrin, 0 in corrole) increases the affinity of H₂OCbl⁺ for anionic ligands through an electrostatic attraction. The topological properties of the electron density in the DFT-modeled compounds are used to explore the nature of the bonding between the metal and the ligands