نتایج جستجو برای: atom bond connectivity index
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In the title compound, [Ni(C24H36P3)Cl], the Ni(II) atom adopts a distorted square-planar geometry with the two neutral P atoms of the tridentate ligand trans to one another. Bond lengths and angles of the phosphide P atom feature a pyramidal geometry of the donor atom, which forms a single bond with the Ni(II) atom, retaining a stereochemically active lone pair.
The geometry of the R2(2)(8) graph set formed between a 2-aminoheterocyclic ring containing an Nsp2 atom (in the 1-position of the ring) and a carboxylic acid has been studied. Collating data from known co-crystal structures containing five- and six-membered heterocyclic rings from the Cambridge Structural Database revealed unexpected differences between two kinds of non-hydrogen contact distan...
The hydrogen-bonded structure of methanol – water mixtures is investigated over the entire alcohol concentration range (from xMethanol = 0.1 to 1.0) at several temperatures, from 300 K down freezing point given mixture. Classical molecular dynamics simulations have been carried out, using all-atom OPLS-AA force field for and TIP4P/2005 model molecules. Simulation trajectories (‘particle configu...
In this talk we consider some results and open problems from the Chemical Graph Theory, mainly concerning structural indices/properties. The Atom Bond Connectivity index, also known as ABC index was defined by Estrada [4] with relation to the energy of formation of alkanes. It was quickly recognized that this index reflects important structural properties of graphs in general. The ABC index was...
The P atom in the title compound, C(16)H(20)NO(2)PS, is bonded in a distorted tetra-hedral P(S)(O)(2)N environment with the bond angles at the P atom in the range 99.37 (7) to 115.68 (5)°. The angles at the amido N atom (with bond-angle sum of 357.8°) confirm its sp(2) character. The C-O-P bond angles are 119.78 (11) and 119.39 (12)°.
let $g=(v,e)$ be a connected graph. the eccentric connectivity index of $g$, $xi^{c}(g)$, is defined as $xi^{c}(g)=sum_{vin v(g)}deg(v)ec(v)$, where $deg(v)$ is the degree of a vertex $v$ and $ec(v)$ is its eccentricity. the eccentric distance sum of $g$ is defined as $xi^{d}(g)=sum_{vin v(g)}ec(v)d(v)$, where $d(v)=sum_{uin v(g)}d_{g}(u,v)$ and $d_{g}(u,v)$ is the distance between $u$ and $v$ ...
The m-order connectivity index (G) m of a graph G is 1 2 1 1 2 1 ... ... 1 ( ) i i im m v v v i i i m d d d G where 1 2 1 ... i i im d d d runs over all paths of length m in G and i d denotes the degree of vertex i v . Also, 1 2 1 1 2 1 ... ... 1 ( ) i i im m v v v i i i ms d d d X G is its m-sum connectivity index. A dendrimer is an artificially manufactured or synth...
The Randić index R(G) of a nontrivial connected graph G is defined as the sum of the weights (d(u)d(v))− 1 2 over all edges e = uv ofG. We prove that R(G) ≥ d(G)/2, where d(G) is the diameter of G. This immediately implies that R(G) ≥ r(G)/2, which is the closest result to the well-known Grafiti conjecture R(G) ≥ r(G) − 1 of Fajtlowicz [4], where r(G) is the radius of G. Asymptotically, our res...
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