Crystal and Molecular Structures of two (Cyclophosphazene)platinum Compounds

[N4P4(CH3)8]PtIICl2•CH3CN and [H2N4P4(CH3)8]2+PtCl42-

John P. OƠbrien, Robert W. Allen, Harry R. Allcock

Research output: Contribution to journalArticle

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Abstract

The antitumor agents cis-dichloro(octamethylcyclotetraphosphazene-N, N")platinum(II)-acetonitrile (compound 1) and the related salt, N, N"-dihydro(octamethylcyclotetraphosphazenium) tetrachloroplatinate (compound 2), have been subjected to X-ray structure analysis. Crystals of 1 were orthorhombic, with the space group P21mn and with a = 10.328 (6) Å, b = 11.439 (6) Å, c = 9.050 (3) Å, and Z=2. The structure was refined by full-matrix least-squares methods to a final R1= 0.048. The eight-membered phosphazene ring in 1 is puckered into a saddle conformation and is coordinated to platinum through two antipodal nitrogen atoms. The ring-platinum binding appears to be by a composite of σ-bonding and π-type interactions. Crystals of compound 2 were monoclinic, with the space group P21/c and with a = 14.911 (2) Å,b= 12.177 (2)Å, c = 11.760 (7)Å, β = 94.94 (2)°, and Z = 4. The structure was solved by heavy-atom methods and was refined by full-matrix least-squares methods to R1= 0.041 and R2= 0.052. The eight-membered phosphazene ring in 2 is protonated at two antipodal nitrogen atoms and is puckered into a distorted chair conformation. The tetrachloroplatinate dianion forms a hydrogen-bonded bridge between parallel sets of phosphazene rings via the protonated nitrogen atoms. The coordination of ring nitrogen atoms to platinum or hydrogen in 1 or 2 causes a lengthening of the P-N bonds that flank the coordination site.

Original languageEnglish (US)
Pages (from-to)2230-2235
Number of pages6
JournalInorganic Chemistry
Volume18
Issue number8
DOIs
StatePublished - Feb 1 1979

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platinum compounds
Platinum Compounds
Molecular structure
phosphazene
Platinum
molecular structure
Crystal structure
nitrogen atoms
platinum
Nitrogen
Atoms
crystal structure
rings
least squares method
Conformations
Hydrogen
Crystals
saddles
hydrogen
matrices

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

@article{832a81c4e2c241468944988152c39cd4,
title = "Crystal and Molecular Structures of two (Cyclophosphazene)platinum Compounds: [N4P4(CH3)8]PtIICl2•CH3CN and [H2N4P4(CH3)8]2+PtCl42-",
abstract = "The antitumor agents cis-dichloro(octamethylcyclotetraphosphazene-N, N{"})platinum(II)-acetonitrile (compound 1) and the related salt, N, N{"}-dihydro(octamethylcyclotetraphosphazenium) tetrachloroplatinate (compound 2), have been subjected to X-ray structure analysis. Crystals of 1 were orthorhombic, with the space group P21mn and with a = 10.328 (6) {\AA}, b = 11.439 (6) {\AA}, c = 9.050 (3) {\AA}, and Z=2. The structure was refined by full-matrix least-squares methods to a final R1= 0.048. The eight-membered phosphazene ring in 1 is puckered into a saddle conformation and is coordinated to platinum through two antipodal nitrogen atoms. The ring-platinum binding appears to be by a composite of σ-bonding and π-type interactions. Crystals of compound 2 were monoclinic, with the space group P21/c and with a = 14.911 (2) {\AA},b= 12.177 (2){\AA}, c = 11.760 (7){\AA}, β = 94.94 (2)°, and Z = 4. The structure was solved by heavy-atom methods and was refined by full-matrix least-squares methods to R1= 0.041 and R2= 0.052. The eight-membered phosphazene ring in 2 is protonated at two antipodal nitrogen atoms and is puckered into a distorted chair conformation. The tetrachloroplatinate dianion forms a hydrogen-bonded bridge between parallel sets of phosphazene rings via the protonated nitrogen atoms. The coordination of ring nitrogen atoms to platinum or hydrogen in 1 or 2 causes a lengthening of the P-N bonds that flank the coordination site.",
author = "OƠbrien, {John P.} and Allen, {Robert W.} and Allcock, {Harry R.}",
year = "1979",
month = "2",
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volume = "18",
pages = "2230--2235",
journal = "Inorganic Chemistry",
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publisher = "American Chemical Society",
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Crystal and Molecular Structures of two (Cyclophosphazene)platinum Compounds : [N4P4(CH3)8]PtIICl2•CH3CN and [H2N4P4(CH3)8]2+PtCl42-. / OƠbrien, John P.; Allen, Robert W.; Allcock, Harry R.

In: Inorganic Chemistry, Vol. 18, No. 8, 01.02.1979, p. 2230-2235.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Crystal and Molecular Structures of two (Cyclophosphazene)platinum Compounds

T2 - [N4P4(CH3)8]PtIICl2•CH3CN and [H2N4P4(CH3)8]2+PtCl42-

AU - OƠbrien, John P.

AU - Allen, Robert W.

AU - Allcock, Harry R.

PY - 1979/2/1

Y1 - 1979/2/1

N2 - The antitumor agents cis-dichloro(octamethylcyclotetraphosphazene-N, N")platinum(II)-acetonitrile (compound 1) and the related salt, N, N"-dihydro(octamethylcyclotetraphosphazenium) tetrachloroplatinate (compound 2), have been subjected to X-ray structure analysis. Crystals of 1 were orthorhombic, with the space group P21mn and with a = 10.328 (6) Å, b = 11.439 (6) Å, c = 9.050 (3) Å, and Z=2. The structure was refined by full-matrix least-squares methods to a final R1= 0.048. The eight-membered phosphazene ring in 1 is puckered into a saddle conformation and is coordinated to platinum through two antipodal nitrogen atoms. The ring-platinum binding appears to be by a composite of σ-bonding and π-type interactions. Crystals of compound 2 were monoclinic, with the space group P21/c and with a = 14.911 (2) Å,b= 12.177 (2)Å, c = 11.760 (7)Å, β = 94.94 (2)°, and Z = 4. The structure was solved by heavy-atom methods and was refined by full-matrix least-squares methods to R1= 0.041 and R2= 0.052. The eight-membered phosphazene ring in 2 is protonated at two antipodal nitrogen atoms and is puckered into a distorted chair conformation. The tetrachloroplatinate dianion forms a hydrogen-bonded bridge between parallel sets of phosphazene rings via the protonated nitrogen atoms. The coordination of ring nitrogen atoms to platinum or hydrogen in 1 or 2 causes a lengthening of the P-N bonds that flank the coordination site.

AB - The antitumor agents cis-dichloro(octamethylcyclotetraphosphazene-N, N")platinum(II)-acetonitrile (compound 1) and the related salt, N, N"-dihydro(octamethylcyclotetraphosphazenium) tetrachloroplatinate (compound 2), have been subjected to X-ray structure analysis. Crystals of 1 were orthorhombic, with the space group P21mn and with a = 10.328 (6) Å, b = 11.439 (6) Å, c = 9.050 (3) Å, and Z=2. The structure was refined by full-matrix least-squares methods to a final R1= 0.048. The eight-membered phosphazene ring in 1 is puckered into a saddle conformation and is coordinated to platinum through two antipodal nitrogen atoms. The ring-platinum binding appears to be by a composite of σ-bonding and π-type interactions. Crystals of compound 2 were monoclinic, with the space group P21/c and with a = 14.911 (2) Å,b= 12.177 (2)Å, c = 11.760 (7)Å, β = 94.94 (2)°, and Z = 4. The structure was solved by heavy-atom methods and was refined by full-matrix least-squares methods to R1= 0.041 and R2= 0.052. The eight-membered phosphazene ring in 2 is protonated at two antipodal nitrogen atoms and is puckered into a distorted chair conformation. The tetrachloroplatinate dianion forms a hydrogen-bonded bridge between parallel sets of phosphazene rings via the protonated nitrogen atoms. The coordination of ring nitrogen atoms to platinum or hydrogen in 1 or 2 causes a lengthening of the P-N bonds that flank the coordination site.

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