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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.
Item Metadata
Title  Crystal and molecular structures of some cyclic phosphonitriles 
Creator  Marsh, Wayne Clifford 
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.

Subject  Phosphonitrile compounds 
Genre  Thesis/Dissertation 
Type  Text 
Language  eng 
Date Available  20110524 
Provider  Vancouver : University of British Columbia Library 
Rights  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 
URI  
Degree  Doctor of Philosophy  PhD 
Program  Chemistry 
Affiliation  Science, Faculty of; Chemistry, Department of 
Degree Grantor  University of British Columbia 
Campus  UBCV 
Scholarly Level  Graduate 
Aggregated Source Repository  DSpace 
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