02759nas a2200229   4500008004100000022001400041245008300055210006900138260007300207300000800280490000800288520196600296653001002262653001602272653002402288653000802312653002202320100002702342700002502369700001602394856011902410       2009                        eng d  a0022-286000aBond length variations: electron number profiles and transferable atomic sizes0 aBond length variations electron number profiles and transferable  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcNOV  a1-80 v9363 a<p>A profile of the number of electrons with distance along the M-X bond in gas-phase diatomic molecules has been obtained from electron density plots calculated using DFT B3LYP 6-311G** method for some representative molecules. This ``number profile'' is compared with that expected from the partitioning of the 1D bond-distance into atom-specific transferable ``hub'' or core atomic sizes of the M and X atoms and another ``axle'' size which is associated with a pair of (bonding) electrons. The ``hub'' size is proportional to a core atom-specific size, r(nZ)(c) with r(nZ)(c)(M) &gt;= r(nZ)(c)(X). For ``single bonds'', the ``hub'' size for M atom is C(M)r(nZ)(c)(M) and for X atom is C(X)r(nZ)(c)(X). The ``axle'' size, DMX, is usually the ordinary (similar to 4a(H)/3 where a(H) is the Bohr radius of the hydrogen atom) or elongated (similar to 2a(H)) bond length of the hydrogen molecule. The ``hub'' and ``axle'' sizes could be characterized ``charge-transfer'' (C(M) = pi(2/3) = 2.144; C(X) = pi(4/3)/2 = 2.300 and D(MX) = 4a(H)/3) or ``neutral'' (CM or C(X) = 1, 2, ... and D(MX) = 2a(H)). We use a new ``static'' or ``peripatetic'' classification for the core sizes which is derived from a new condition for metallization in elements based on atomic size. The charge-transfer distance, d(MX)(+/-), is usually found for ``static'' conditions while the ``neutral'' description is usually found when X = F or for ``peripatetic'' conditions. Such a partitioning is seen to agree with that from the plot of the total number of electrons, N(el), vs r along a bond axis. The Nel vs r plots from each atom are described by a simple hydrogen-atom-like function which differ away (''out'') or towards (''in'') the M-X bond. Thus N(in,out)(M, X) = (Z(M,X) +/- 1) exp (-r/B(in,out)) where the minus sign is associated with M and plus sign with X and Bin, out being related inversely to the Slater orbital exponent. (C) 2009 Elsevier B.V. All rights reserved.</p>10aB3LYP10aBond length10aBond-stretch isomer10aDFT10aDiatomic molecule1 aGanguly, Parthasarathy1 aKulkarni, Bhakti, S.1 aPal, Sourav  uhttps://library.ncl.res.in/content/bond-length-variations-electron-number-profiles-and-transferable-atomic-sizes-001813nas a2200253   4500008004100000022001400041245013200055210006900187260010200256300001400358490000800372520087400380653000601254653001901260653000801279653001201287653002701299653002601326653002401352100002501376700001901401700001601420856012301436       2013                        eng d  a0974-362600aRole of substituents on the reactivity and electron density profile of diimine ligands: a density functional theory based study0 aRole of substituents on the reactivity and electron density prof  aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScSEP  a1247-12580 v1253 a<p>In this paper, we study the reactivity of diimines like 2, 2(')-bipyridine, 1, l0-phenanthroline and 1, 2, 4-triazines using density-based reactivity descriptors. We discuss the enhancement or diminution in the reactivity of these ligands as a function of two substituent groups, namely methyl (-CH3) group and phenyl (-C6H5) group. The global reactivity descriptors explain the global affinity and philicity of these ligands, whereas the local softness depicts the particular site selectivity. The inter-molecular reactivity trends for the same systems are analysed through the philicity and group philicity indices. The sigma-donor character of these ligands is quantified with the help of electron density profile. In addition, the possible strength of interaction of these ligands with metal ions is supported with actual reaction energies of Ru-L complexes.</p>10a210a2 `-bipyridine10aDFT10adiimine10aReactivity descriptors10aRu-ligand interaction10asubstituent effects1 aKulkarni, Bhakti, S.1 aMishra, Deepti1 aPal, Sourav  uhttps://library.ncl.res.in/content/role-substituents-reactivity-and-electron-density-profile-diimine-ligands-density-0