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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U2 - 10.1021/ic50198a037
DO - 10.1021/ic50198a037
M3 - Article
AN - SCOPUS:0018663768
SN - 0020-1669
VL - 18
SP - 2230
EP - 2235
JO - Inorganic chemistry
JF - Inorganic chemistry
IS - 8
ER -