V Raghukumar

Publications (6)3.13 Total impact

• Article: 5-Amino-4-(4-di-methyl-amino-phenyl)-2-(4-methoxy-phenyl)-7-(pyrrolidin-1-yl)-1,6-naphthyridine-8-carbo-nitrile

  Sundari Bhaskaran, M. Yogavel, V. Rajakannan, R. Krishna, D. Velmurugan, V. Raghukumar
  Acta Crystallographica Section E. 01/2003; 59(2):o200-o202.
• Article: Spectral and photophysical properties of 1,6-naphthyridine derivatives: a new class of compounds for nonlinear optics.

  V K Indirapriyadharshini, P Ramamurthy, V Raghukumar, V T Ramakrishnan
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  ABSTRACT: 1,6-Naphthyridines are a class of compounds that exhibit second harmonic generation on excitation with a Nd-YAG laser (1064 nm). Solvatochromism has been used to estimate enhancement in the dipole moments on excitation and the values of first-order hyperpolarizability, beta. Photophysical studies on the title compounds show that they have a fluorescence lifetime of about 10 ns and fluorescence quantum yield of approximately 0.05-0.1 in different solvents. Kurtz powder method has been used to find the NLO efficiency of the compounds with reference to urea.
  Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 07/2002; 58(8):1535-43. · 2.10 Impact Factor
• Article: 3-amino-4'-methyl-5-ethylbiphenyl-2,4-dicarbonitrile and 3-amino-4'-(n,n-diethylamino)-5-ethylbiphenyl-2,4-dicarbonitrile.

  A Subbiah Pandi, D Velmurugan, S Shanmuga Sundara Raj, H K Fun, V Raghukumar, V T Ramakrishnan
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  ABSTRACT: In the title compounds, C17H15N3 and C20H22N4, the methyl derivative crystallizes with two molecules in the asymmetric unit, while the N,N-diethylamino derivative crystallizes with one molecule per asymmetric unit. The biphenyl twist angle for both molecular structures is approximately 45 degrees. The molecular packing is stabilized by N-H...N hydrogen bonds.
  Acta Crystallographica Section C Crystal Structure Communications 07/2001; 57(Pt 6):723-5. · 0.52 Impact Factor
• Article: 5-amino-4-(4-diethylaminophenyl)-2-phenyl-7-(pyrrolidin-1-yl)-1,6 -naphthyridine-8-carbonitrile.

  L Govindasamy, D Velmurugan, V Raghukumar, I H Suh, V T Ramakrishnan
  Acta Crystallographica Section C Crystal Structure Communications 02/2000; 56 ( Pt 1):80-1. · 0.52 Impact Factor
• Article: Spectral and photophysical properties of 1,6-naphthyridine derivatives: a new class of compounds for nonlinear optics

  V.K Indirapriyadharshini, P Ramamurthy, V Raghukumar, V.T Ramakrishnan
  [show abstract] [hide abstract]
  ABSTRACT: 1,6-Naphthyridines are a class of compounds that exhibit second harmonic generation on excitation with a Nd–YAG laser (1064 nm). Solvatochromism has been used to estimate enhancement in the dipole moments on excitation and the values of first-order hyperpolarizability, β. Photophysical studies on the title compounds show that they have a fluorescence lifetime of about 10 ns and fluorescence quantum yield of ∼0.05–0.1 in different solvents. Kurtz powder method has been used to find the NLO efficiency of the compounds with reference to urea.
  Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy.
• Article: 5-Amino 4-(4-dimethylaminophenyl)-2-(4methoxyphenyl)-7-(pyrrolidin-1-yl)- 1,6-naphthyridine-8-carbonitrile

  M Yogavel, V Rajakannan, R Krishna, D Velmurugan, V Raghukumar
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  ABSTRACT: In the title compound, $C_{28}H_{28}N_{6}O$, the naphthyridine moiety is planar and the pyrrolidine ring adopts a half-chair conformation. The dimethylaminophenyl substituent is nearly orthogonal to the naphthyridine moiety, while the methoxyphenyl ring is twisted from it by 11.3 (2). The molecular structure is stabilized by an N–H...$ \pi$ interaction. In the solid state, the inversion-related molecules are linked to form N– H...N hydrogen-bonded dimers. The molecular packing is stabilized by weak C–H..$\pi$ and $\pi$-$\pi$ interactions.