Bonding Properties of Diphosphacyclobutadienes

Veszprémi, Tamás; Gleiter, Rolf; Fluck, E.; Svara, J.; Neumüller, Bernhard

doi:10.1002/cber.19881211129

Cited by 12 publications

(5 citation statements)

References 14 publications

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“…167 In all cases the PC bond lengths were equal and in the range of the aromatic PC bonds (1.687 Å from the X-ray structure). 167 It is worth noting that no NICS data has been reported for λ 5 -phosphinines as yet.…”

Section: -Triphosphininementioning

confidence: 84%

“…The X-ray structure of the heavily substituted 1,1,3,3,5,5-hexakis(dimethylamino)-1λ 5 ,3λ 5 ,5λ 5 -triphosphinine was planar . In all cases the PC bond lengths were equal and in the range of the aromatic PC bonds (1.687 Å from the X-ray structure) . It is worth noting that no NICS data has been reported for λ 5 -phosphinines as yet.…”

Section: λ5-phosphinine (33) 1λ53λ55λ5-triphosphininementioning

confidence: 92%

“…This presumption was not only in contrast with the expectations, but also with other experimental results as well. By comparing the photoelectron spectra of 1,1,3,3-tetrakis(dimethylamino)-1λ 5 ,3λ 5 diphosphacyclobutadiene with that of 1,1,3,3,5,5hexakis(dimethylamino)-1λ 5 ,3λ 5 ,5λ 5 -triphosphinine, 167 a great similarity has been found which is completely unexpected if a six-membered system is compared to a four-membered one. 168 Rationalization of these observations could be given by using the island model of Dewar et al; 169 however, that model invokes explicitly the d-orbital participation in the bonding that has been shown 111 to be of little importance according to ab initio calculations.…”

Section: B Four-membered Ringsmentioning

confidence: 94%

“…However, the calculated structure is not entirely planar; the hydrogens on the carbon atoms move somewhat out from the plane. The X-ray structure of the heavily substituted 1,1,3,3,5,5-hexakis(dimethylamino)-1λ 5 ,3λ 5 ,5λ 5 -triphosphinine was planar . In all cases the PC bond lengths were equal and in the range of the aromatic PC bonds (1.687 Å from the X-ray structure) .…”

Section: λ5-phosphinine (33) 1λ53λ55λ5-triphosphininementioning

confidence: 94%

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Aromaticity of Phosphorus Heterocycles

2001

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Heterophospholes 1231 D. Six-Membered Rings 1233 1. Phosphinine (3) 1233 2. Azaphosphinines 1235 3. Di-and Triphosphinines 1235 4. Hexaphosphinine (P 6 ) 1236 E. Azaphosphaullazine (4,9b-Diaza-2phosphacyclopenta[c,d]phenalene) (16) 1236 IV. "B"-and "C"-Type Bonding, Phosphorus Lone Pair in Delocalized Aromatic Systems 1236 A. Four-Membered Rings 1236 B. Five-Membered Rings 1237 1. Phosphole (4) 1237 2. 3H-1,3-Azaphospholes 1238 3. Polyphospholes 1238 C. Six-Membered Rings 1239 1. Cyclic Phosphinocarbenes 1239 2. Cyclic Phosphinoboranes 1240 D. Nine-Membered Rings 1240 E. Fused Systems 1240 V. "D"-Type Bonding 1241 A. Comparison of the Bonding in H 3 PdCH 2 and HPdCH 2 1241 B. Four-Membered Rings 1241 C. λ 5 -Phosphinine (33), 1λ 5 ,3λ 5 ,5λ 5 -Triphosphinine 1242 VI. Outlook 1243 VII. Acknowledgments 1243 VIII. References 1243

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Section: -Triphosphininementioning

confidence: 84%

Section: λ5-phosphinine (33) 1λ53λ55λ5-triphosphininementioning

confidence: 92%

Section: B Four-membered Ringsmentioning

confidence: 94%

Section: λ5-phosphinine (33) 1λ53λ55λ5-triphosphininementioning

confidence: 94%

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Aromaticity of Phosphorus Heterocycles

2001

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“…Es ist von uns schon früher darauf hingewiesen worden, daß sich das chemische Verhalten des l,r,3,3'-T etrakis(dim ethylam ino)-l/l5,325-diphosphets 1 am besten als Doppel-Ylid mit zwei Carbanionen beschreiben läßt [1][2][3][4]. Mit Säuren tritt Protonierung zum entsprechenden Diphosphetium -Kation ein.…”

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Notizen: Das 1,1′,3,3′-Tetrakis(dimethylamino)-1λ⁵,3 λ⁵-diphosphetium-Kation / The 1,1′,3,3′-Tetrakis(dimethylamino)-1λ⁵,3 λ⁵-diphosphetium Cation

Fluck¹,

Heckmann

Lange

1993

Zeitschrift Für Naturforschung B

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Photoelectron Spectra of λ‐Di‐ and ‐Triphosphabenzenes

Gleiter

Veszprémi

Fluck³

1991

Chem. Ber.

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The He(1) photoelectron spectra of 1,1,3,3-tetrakis(dimethyl-calculations carried out by using the MNDO procedure. The amino)-lh5,3h5-diphosphabenzene (1 a), 1,1,3,3,5,5-hexakis(di-investigations reveal that the first bands correspond to n-MOs methylamino)-lh5,3h5,5h5-triphosphabenzene (2a), 4-tert-bu-which are mainly localized on the C atoms of the six-memt y l -1 , 1 , 3 , 3 -t e t r a k i s ( d i m e t h y l a m i n o ) -l h 5 , e nbered ring. The MO calculations predict a strong negative net zene (3a), and the substitution products 4a and 5a of l a have charge for the ring carbon atoms adjacent to the P atoms and been recorded. The assignment of the PE spectra is based on strong positive net charges for the P atoms. a comparison of the PE spectra of related species with the MO In recent years the electronic structures of many heterosubstituted benzenes have been studied by He(1) photoelectron (PE) spectroscopy. The 7c-bands of most of these spectra, for example pyridine ' ), phosphabenzene2), arsabenzene2), stibabenzene2), and bi~mabenzene~) have been explained by the perturbing effect of the heteroatom and could be correlated with the x-bands of benzene2-9 In contrast to these species, the electronic structure of the six-membered phosphazenes (e. g. six-membered phosphonitrile halides) is very different 5,6). Although 6 n-electrons are available, the x-system is not delocalized; instead, it is described by localized three-center n-bonds 5,6). The electronic structure of diphosphazenes7) as well as diphosphacyclobutadienes*) can also be rationalized by using the island model'). The recently synthesized 1,1,3,3-tetrakis-(dimethylamino)-lh5,3~5-diphosphabenzene (1 a) ' ), 1,1,3,3,5,5-hexakis(dimethylarnino)-1 h5,3h5,5h'-triphosphabenzene (2a)"), 4-tert-butyl-l,l,3,3-tetrakis(dimet hy1amino)-1 h',3h5,5h3-triphosphabenzene (3 a) as well as the substitution products of 1 , 4 a and 5a9912) provide good test cases to check the bonding models for such phosphorus species. The method of choice to investigate the electronic structure of 1-5 is photoelectron spectros-COPY. PE Spectra and CalculationsThe PE spectra of l a -3 a are shown in Figure 1. The data recorded for 1 a -5a are collected in Table 1. Common to all five spectra are two peaks in the low-energy region between 6 and 7.5 eV, followed by a very intense and broad peak between 8 and 9 eV. To interpret these data we make use of the observation that Koopmans' approximation also holds13) for phosphorus compounds, as exemplified on many o c c a~i o n s~~~~~* '~-~~) .We can hence set as equal the negative value of the calculated orbital energies, --si, to the measured vertical ionization energies, I.* The calculations were carried out by using the MNDO method17) for the model compounds lb-5b. The calculations are based on the X-ray

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Bonding Properties of Diphosphacyclobutadienes

Cited by 12 publications

References 14 publications

Aromaticity of Phosphorus Heterocycles

Aromaticity of Phosphorus Heterocycles

Notizen: Das 1,1′,3,3′-Tetrakis(dimethylamino)-1λ⁵,3 λ⁵-diphosphetium-Kation / The 1,1′,3,3′-Tetrakis(dimethylamino)-1λ⁵,3 λ⁵-diphosphetium Cation

Photoelectron Spectra of λ‐Di‐ and ‐Triphosphabenzenes

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Bonding Properties of Diphosphacyclobutadienes

Cited by 12 publications

References 14 publications

Aromaticity of Phosphorus Heterocycles

Aromaticity of Phosphorus Heterocycles

Notizen: Das 1,1′,3,3′-Tetrakis(dimethylamino)-1λ5,3 λ5-diphosphetium-Kation / The 1,1′,3,3′-Tetrakis(dimethylamino)-1λ5,3 λ5-diphosphetium Cation

Photoelectron Spectra of λ‐Di‐ and ‐Triphosphabenzenes

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Notizen: Das 1,1′,3,3′-Tetrakis(dimethylamino)-1λ⁵,3 λ⁵-diphosphetium-Kation / The 1,1′,3,3′-Tetrakis(dimethylamino)-1λ⁵,3 λ⁵-diphosphetium Cation