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 Crystal and molecular structures of some cyclic phosphonitriles
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Crystal and molecular structures of some cyclic phosphonitriles Marsh, Wayne Clifford
Abstract
Single crystal Xray diffraction methods have been used to determine the structures of four cyclic phosphonitriles: 1,1,5,5tetrafluoro3,3,7,7tetramethylcyclotetra phosphonitrile, N(4)P(4)F(4)Me(4) ; 1,1,3,3,5,5hexafluoro7,7dimethyl cyclotetraphosphonitrile, N(4)P(4)F(4)Me(2); hexaphenoxycyclotriphosphonitrile, [NP(OPh)2](3) and dodeca(dimethylamino)cyclohexaphosphonitrilechlorocopper (II) dichlorocuprate (I), [formula omitted]. Intensity measurements were made on a Datex automated General Electric diffractometer using a scintillation counter; CuK [symbol omitted], radiation being used for the first three structure determinations and MoK [symbol omitted] radiation for the fourth. The structure of N(4)P(4)F(4)Me(4) has been determined by Patterson and Fourier methods and refined by fullmatrix leastsquares. The molecule is situated on a C(2) axis, and the phosphonitrilic ring has the 'saddle' conformation. Different electronegativities of the substituent groups result in two distinct PN bond lengths, 1.53 and 1.59 Å explicable in terms of π bonding theories. Patterson, Fourier, and fullmatrix leastsquares methods have been used to determine the structure of N(4)P(4)F(6)Me(2). This molecule is also situated on a C(2) axis and has the 'saddle' conformation, but tends strongly towards planarity. The most interesting features of the ring are four distinct PN bond lengths (1.584, 1.470, 1.532, and 1.487 Å), and large valency angles (145°) at nitrogen, which are explicable in terms of π bonding theories. The structure of [NP(CPh)2]3 was determined from Patterson and Fourier syntheses, and refinement of positional and thermal parameters of the atoms by blockdiagonal leastsquares. The phosphonitrilic ring is slightly nonplanar, with two nitrogen atoms displaced by 0.15 Å in opposite directions from the plane of the other four (3P and 1N) atoms. The conformations of the phenoxy groups are different at the three phosphorus atoms, and there are small deviations among chemicallyequivalent angles; these differences are probably a result of intra and intermolecular steric effects. There are no differences among chemically equivalent bond lengths, the mean distances being PN 1.575(2), PO 1.582(2), 0C 1.406(3) Å. The structure of [formula omitted] was determined by Patterson, Fourier, and fullmatrix leastsquares methods. The structure is ionic with the cation and anion each situated on a C(2) axis. The cation consists of a Cu(II) bonded to four nitrogens of the phosphonitrilic ring (NCu 2.07 Å) and a chlorine (CℓCu 2.28 Å) in a distorted square pyramid. The Cu(I)Cℓ2¯ anion is linear with a CuCℓ bond length of 2.11 Å. There are two distinct PN bond lengths in the phosphonitrilic ring, 1.62 and 1.55 Å, explicable by π bonding theory. The overall shape of the structure is determined primarily by steric effects and the distortion of the phosphonitrilic ring caused by the bonding to copper.
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Title 
Crystal and molecular structures of some cyclic phosphonitriles

Creator  
Publisher 
University of British Columbia

Date Issued 
1970

Description 
Single crystal Xray diffraction methods have been used to determine the structures of four cyclic phosphonitriles: 1,1,5,5tetrafluoro3,3,7,7tetramethylcyclotetra
phosphonitrile, N(4)P(4)F(4)Me(4) ; 1,1,3,3,5,5hexafluoro7,7dimethyl
cyclotetraphosphonitrile, N(4)P(4)F(4)Me(2); hexaphenoxycyclotriphosphonitrile, [NP(OPh)2](3) and dodeca(dimethylamino)cyclohexaphosphonitrilechlorocopper (II) dichlorocuprate (I), [formula omitted]. Intensity measurements were made on a Datex automated General Electric diffractometer using a scintillation counter; CuK [symbol omitted], radiation being used for the first three structure determinations and MoK [symbol omitted] radiation for the fourth.
The structure of N(4)P(4)F(4)Me(4) has been determined by Patterson and Fourier methods and refined by fullmatrix leastsquares. The molecule is situated on a C(2) axis, and the phosphonitrilic ring has the 'saddle' conformation. Different electronegativities of the substituent groups result in two distinct PN bond lengths, 1.53 and 1.59 Å explicable in terms of π bonding theories.
Patterson, Fourier, and fullmatrix leastsquares methods have been used to determine the structure of N(4)P(4)F(6)Me(2). This molecule is also situated on a C(2) axis and has the 'saddle' conformation, but tends strongly towards planarity. The most interesting features of the ring are four distinct PN bond lengths (1.584, 1.470, 1.532, and 1.487 Å), and large valency angles (145°) at nitrogen, which are explicable in terms of π bonding theories.
The structure of [NP(CPh)2]3 was determined from Patterson and Fourier syntheses, and refinement of positional and thermal parameters of the atoms by blockdiagonal leastsquares. The phosphonitrilic ring is slightly nonplanar, with two nitrogen atoms displaced by 0.15 Å in opposite directions from the plane of the other four (3P and 1N) atoms. The conformations of the phenoxy groups are different at the three phosphorus atoms, and there are small deviations among chemicallyequivalent angles; these differences are probably a result of intra and intermolecular steric effects. There are no differences among chemically equivalent bond lengths, the mean distances being PN 1.575(2), PO 1.582(2), 0C 1.406(3) Å. The structure of [formula omitted] was
determined by Patterson, Fourier, and fullmatrix leastsquares methods. The structure is ionic with the cation and anion each situated on a C(2) axis. The cation consists of a Cu(II) bonded to four nitrogens of the phosphonitrilic ring (NCu 2.07 Å) and a chlorine (CℓCu 2.28 Å) in a distorted square pyramid. The Cu(I)Cℓ2¯ anion is linear with a CuCℓ bond length of 2.11 Å. There are two distinct PN bond lengths in the phosphonitrilic ring, 1.62 and 1.55 Å, explicable by π bonding theory. The overall shape of the structure is determined primarily by steric effects and the distortion of the phosphonitrilic ring caused by the bonding to copper.

Genre  
Type  
Language 
eng

Date Available 
20110524

Provider 
Vancouver : University of British Columbia Library

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For noncommercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.

DOI 
10.14288/1.0060022

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Degree Grantor 
University of British Columbia

Campus  
Scholarly Level 
Graduate

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DSpace

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For noncommercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.