There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The Pharmacological Basis of Therapeutics A Textbook of Pharmacology, Toxicology and Therapeutics for Physicians and Medical Students. By Prof. Louis Goodman and Prof. Alfred Gilman. Pp. xiii + 1383. (New York: The Macmillan Company, 1941.) 50s. net.

The Pharmacological Basis of Therapeutics

介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。

Kirk-Othmer Encyclopedia of Chemical Technology数据库介绍及实例

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Crystals of 7,11-bis(2,4-dichlorophenyl)-2,4-dimethyl-2,4-diazaspiro[5.5]undecane -1,3,5,9-tetraone were grown in polar solvents and subjected to single crystal X-ray diffraction. The molecular crystal is Triclinic, P-1, a= 8.3734 (19) A, b= 12.382 (3) A, c= 12.871 (3) A, α= 66.639 (7) ∘, β= 85.148 (7) ∘, γ= 70.690 (6) ∘, V= 1154.5 (5)A 3, Z= 2, D calc= 1.519 g cm −3. The optimized molecular structure of the studied compound using B3LYP/6-311G(d,p) method showed good agreement with the X-ray structure. The electronic and spectroscopic properties of the title compound were predicted. The NBO calculations were used to calculate the natural atomic charges at the different atomic sites as well as the intramolecular charge transfer (ICT) interactions among the most significant natural orbitals. The high LP(N) → BD*(2)C-O ICT interaction energies indicate strong electron delocalization from the lone pair of the N-atoms of the pyrimidinetrione ring to the adjacent carbonyl groups. In contrast, the small LP(O) →BD*(1)C-H stabilization energies (E (2)) indicated weak C-H—O interactions. Experimentally, the studied compound showed the most intense electronic transition band at 232 nm which is calculated using TD-DFT method as a shoulder at 231.3 nm (f =0.0832) and it belongs to H-3/H-1 →L+1 and H-2 →L+2 excitations. The GIAO calculated 1H and 13C NMR chemical shifts showed good correlations with the experimental data.

/pdf/crystal-structure-of-7-11-bis-2-4-dichlorophenyl-2-4-2b23esnu8n.pdf

Crystal Structure of 7,11-bis(2,4-dichlorophenyl)-2,4-dimethyl-2,4- diazaspiro[5.5]undecane -1,3,5,9-tetraone and its computational studies

The geometrical structures of six square-planar diacetylplatinum(II) complexes ([Pt(Ac)2L], L = hydrazine-type ligand) were calculated using six (B3LYP, CAM-B3LYP, B3PW91, M06, M06HF and PBE) DFT methods and one post-Hartree–Fock (MP2) method combined with 6-31G(d,p) basis sets for nonmetal atoms and LANL2DZ for Pt. Using percent relative errors, M06HF and MP2 are best for predicting Pt–N bond distances, but worst for Pt–C bond distances, whereas B3PW91 is best. Pt–N(pyridine) bonds have higher electron density at the bond critical points than Pt–N(hydrazone) bonds, and the former are more covalent than the latter. Further, Pt–C bonds trans to hydrazone moieties are more covalent than Pt–C bonds trans to Pt–N(pyridine) bonds. Pt–C bonds are mainly due to Pt→Ac back donation rather than Ac→Pt donation; σ-bonding is less important in this case, consistent with the high π-acidity and strong trans effect of acetyl groups. In contrast, Pt→N back donation is negligible and Pt–N bonds are mainly due to N→Pt σ-donation, which stabilizes trans Pt–C bonds.

/pdf/applicability-of-nbo-and-aim-topology-analyses-to-chemical-yy6cysw253.pdf

Applicability of NBO and AIM Topology Analyses to Chemical Bonding in Some Diacetylplatinum(II) Complexes

Synthesis, characterisation and density functional theory (DFT) studies of a triazine ring with a mixed ligand Schiff base complexes

UV–Vis spectroscopy was used to investigate two new charge transfer (CT) complexes formed between the K+-channel-blocker amifampridine (AMFP) drug and the two π-acceptors 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) in different solvents. The molecular composition of the new CT complexes was estimated using the continuous variations method and found to be 1:1 for both complexes. The formed CT complexes’ electronic spectra data were further employed for calculating the formation constants (KCT), molar extinction coefficients (eCT), and physical parameters at various temperatures, and the results demonstrated the high stability of both complexes. In addition, sensitive spectrophotometric methods for quantifying AMFP in its pure form were proposed and statistically validated. Furthermore, DFT calculations were used to predict the molecular structures of AMFP–DDQ and AMFP–TCNE complexes in CHCl3. TD-DFT calculations were also used to predict the electronic spectra of both complexes. A CT-based transition band (exp. 399 and 417 nm) for the AMFP–TCNE complex was calculated at 411.5 nm (f = 0.105, HOMO-1 → LUMO). The two absorption bands at 459 nm (calc. 426.9 nm, f = 0.054) and 584 nm (calc. 628.1 nm, f = 0.111) of the AMFP–DDQ complex were theoretically assigned to HOMO-1 → LUMO and HOMO → LUMO excitations, respectively.

New Charge Transfer Complexes of K+-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection; Solution Investigations and DFT Studies.

The new homoleptic [Ag(5-nitroquinoline)2]ClO4 centrosymmetric complex was synthesized and its structure aspects were investigated. It crystallized in the monoclinic space group C2/c with a = 10.0279(2) Å, b = 13.2295(3) Å, c = 14.7552(3) Å and β = 102.1050(10)° while V = 1913.96(7) Å3 and half molecule as asymmetric formula. The Ag(I) is coordinated with two symmetrically related 5-nitroquinoline ligand units via the heterocyclic nitrogen atom with Ag-N distance of 2.146(6) Å and N1-Ag-N1 angle of 173.0(3)°. The two coordinated 5-nitroquinoline have anti configuration to one another and the perchlorate anion is set freely uncoordinated. The only Ag…O interactions are Ag1…O2 (3.110 Å) and Ag1…O1 (3.189 Å) which occur between the Ag(I) in one complex unit and the O-atoms from the NO2 groups in the neighbouring complex units. Hence, Ag(I) has coordination number 2 and its coordination geometry is slightly bent. Hirshfeld analysis indicated that the O…H (51.1%), C…H (11.8%), H…H (10.8%) and C…C (8.9%) contacts are the most common. Exclusively, the O…H, C…O, N…O, O…O and Ag…O contacts are the only shorter contacts than the vdWs radii sum of the interacting atoms. The studied Ag(I) complex showed good antimicrobial activity. It has comparable antibacterial activity against P. vulgaris (MIC = 9.7 μg/mL) and S. aureus (39.1 μg/mL) to Gentamycin (4.8 and 9.7 μg/mL, respectively) while better antifungal activity against A. fumigatus (MIC = 39.1 μg/mL) than Ketoconazole (156.2 μg/mL).

https://www.mdpi.com/2073-8994/14/3/547/pdf?version=1646790253

Saied M. Soliman

Papers

Crystal Structure of 7,11-bis(2,4-dichlorophenyl)-2,4-dimethyl-2,4- diazaspiro[5.5]undecane -1,3,5,9-tetraone and its computational studies

Applicability of NBO and AIM Topology Analyses to Chemical Bonding in Some Diacetylplatinum(II) Complexes

Synthesis, characterisation and density functional theory (DFT) studies of a triazine ring with a mixed ligand Schiff base complexes

New Charge Transfer Complexes of K+-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection; Solution Investigations and DFT Studies.

Synthesis, Molecular and Supramolecular Structure Aspects, and Antimicrobial Activity of the Centrosymmetric [Ag(5-Nitroquinoline)2]ClO4 Complex