The crystal structure of 2-chloro-1,3-bis(2,4,6-trimethylphenyl)-4,4-dimethyl-1,3,2λ³,4-diazaphosphasiletidine

Crystal structure of 2-chloro-1,3-di-tert-pentyl-4,4-diphenyl-1,3,2λ 3,4-diazaphosphasiletidine, C22H32ClN2PSi

“…The P-Cl bonds of the title compound are remarkably elongated (P1-Cl1 2.1963(7) Å, P2-Cl2 2.1967(7) Å) compared to the P-Cl distance in PCl 3 (2.034 Å [14]) and exceed the sum of the covalence radii [15]. A comparison of the average Si-N, P-N and P-Cl distances in the title compound and the analogous distances of the formerly published dimethylsilanederivative [7] does not give evidence for substitution effects [16] and only shows a small difference (numerically significant but chemically not relevant) in the case of the P-Cl bond: Si-N 1.7406(15) Å average (in the title compound) vs. 1.7441(17) Å average (in the mentioned dimethylderivative); P-N 1.6910(16) Å average vs. 1.6856(17) Å average; P-Cl 2.1965(7) Å average vs. 2.1813(7) Å). The tert-pentyl groups in the solid of the title compound are disordered to give two positions of the ethyl moiety in each case (Exptl.…”

“…The Si-N bond lengths (Si1-N1 1.7392(15) Å, Si1-N2 1.7418(16) Å; Si2-N3 1.7387(15) Å, Si2-N4 1.7427(15) Å) exceed the expected lenght of a Si-N single bond (1.724(4) Å [9]) but correspond to those in related cyclosilazanes [7,[10][11][12][13]. In contrast, the P-N distances are shorter (P1-N1 1.6928(15) Å, P1-N2 1.6889(18) Å; P2-N3 1.6932(15) Å, P2-N4 1.6891(16) Å) than reported for a typical single bond (1.704(4) Å [9]), but they also correspond to those in the first structurally characterized chlorosubstituted diazaphosphasiletidine [7]. The P-Cl bonds of the title compound are remarkably elongated (P1-Cl1 2.1963(7) Å, P2-Cl2 2.1967(7) Å) compared to the P-Cl distance in PCl 3 (2.034 Å [14]) and exceed the sum of the covalence radii [15].…”

“…The first synthesis was described in the year 1963 and the compounds of the class have attracted considerable attention in phosphorus chemistry [3][4][5][6][7][8]. Crystals of the first structurally characterised chlorosubstituted diazaphosphasiletidine, 2-chloro-1,3-bis(2,4,6-trimethylphenyl)-4,4-dimethyl-1,3,2λ 3 ,4-diazaphosphasiletidine [7] contained approximately 12% of a second compound, namely 2-chloro-1,3-bis(2,4,6-trimethylphenyl)-4-chloro-4-methyl-1,3,2λ 3 ,4-diazaphosphasiletidine. With respect to this impurity a Si,Si-diphenylsubstituted diazaphosphasiletidine, the title compound, has been introduced to preparative chemistry to avoid problems related to the content of Si,Pbis(chloro)functionalized species always present in samples of the Si,Si-dimethylderivative.…”

Crystal structure of 1,3-di-tert-butyl-2-chloro-1,3,2-diazaphosphorinane − a saturated six-membered phosphorus nitrogen heterocycle with a partially flattened chair conformation and a long PIII—Cl bond

“…The fourth ring member >E, joining the class-defining Cl-P<(NR) 2 fragment, is an >SiR 2 group in most cases (e.g. Breuers & Frank, 2016;Gü n et al, 2017;Mo et al, 2018;Mo & Frank, 2019;Veith et al, 1988) but some compounds containing >C N-R (Brazeau et al, 2012), >B-Ph (Konu et al, 2008) and >As-Cl (Hinz et al, 2015) have also been synthesized and structurally characterized. In contrast to the aforementioned compounds with four-and five-membered rings, six-membered NHPs and NHPCls are less present in recent publications, although 2-chloro-1,3,2diazaphophorinanes H 2 C<(CH 2 NR) 2 >P-Cl, for instance, have been known since the early 1970s Nifant'ev et al, 1977).…”