Fine Tuning of the Substituents on the N-Geminal Phosphorus/Silicon-Based Lewis Pairs for the Synthesis of Z-Type Silyliminophosphoranylalkenes

Abstract

I. Synthesis of compounds 1a-4a and 1b-4b II. X-ray crystallographic data III. Ortep diagrams IV. Selected bond lengths V.

Synthesis and Characterization of Two β-Diketiminato Tin(Ⅳ) Compounds

“…Since the Lewis acidity of the SnMe 2 Cl and SnMe 3 group is weaker than that of the SnX 3 (X＝Cl, Br) groups, the as-formed heterocycles A and B are not stable. [9,10] These heterocycles would further rearrange . [9] However, we tried to isolate such heterocycles by controlling the reaction temperature and/or time but failed.…”

“…The similar structural feature has been found only in compounds of Yb, [13] group 2 alkyls, [11] and [N(Ar')C(Me)＝CHC-Scheme 2 Formation mechanism of compounds 1 and 2 (＝NAr')CH 2 SnMe 2 ] 2 •C 7 H 8 (3). [12a] The bond angles in the fragment B of 2 are 88.11 (10) 7), and 123.0(2)° (Sn(1') -N(1)-C(8)). The fragment B in 2 is very similar to that in 3: the latter having Sn(1)-N(2'), Sn(1)-C 17, C(3)-C (17) and N(2)-C(3) bond lengths of 2.387(6), 2.130(6), 1.503 9and 1.330(9) Å, respectively, and C 17 As clearly presented in Figure 1, surprisingly, ethyl in 2 is not given single definite localization but two, while isopropyl in 1 or 3 is fixed as normal.…”

“…[3,5a,7] The compounds consisting of amino group and Lewis pairs with MMe 3 (M＝Si, Ge, Sn) group undergo dipolar addition reactions with alkyne molecules to form heterocyclic intermediates which rearrange through a N-M bond cleavage and concomitant N-P double bond formation due to the Lewis acidity of the MMe 3 group being weaker than that of the MCl 3 groups. [9,10] Thus, it indicates that the reactivity of center atom-nitrogen bond depends on the Lewis acidity of the MCl 3 -n Me n (n＝ 0, 3) group. In 2011, Zhu and his co-workers [3] found that temperature was the main factor to cause versatile L ligation modes of Bi(III) compounds.…”

Non-conventional Lewis Acids and Bases in Frustrated Lewis Pair Chemistry

“…More recently, a series of N-geminal phosphorus/silicon Lewis pairs have been reported [92]. These compounds, of the form Ph 2 PN(Ar)SiCl 3Àn Me n (where Ar ¼ 2,4,6-Me 3 C 6 H 2 or 2,6-iPr 2 C 6 H 3 , n ¼ 0,1,2,3), were found to react with methyl propiolate and dimethyl acetylenedicarboxylate to give zwitterionic heterocycles (Scheme 28).…”

Hexacoordinate Silicon Compounds with a Dianionic Tetradentate (N,N′,N′,N)-Chelating Ligand

“…Whereas the former preferentially bind to Si atoms that carry strongly electron withdrawing groups (e.g., formation of pyridine adducts of halosilanes, Scheme 1, A, [1][2][3]), the latter offer greater opportunities of creating five-and six-coordinate silicon compounds even in case of the absence of halides from the silicon coordination sphere (e.g., pentacoordinate silicon with SiC 5 coordination sphere, B [4][5][6]; and hexacoordinate silicon with a tetradentate chelator and two Si-CH 3 groups, C [7]). For various reasons, such as activation of Si-X bonds by silicon hypercoordination [8][9][10][11][12][13][14][15][16], exploring special electronic/optical properties arising from the higher coordination number of silicon in combination with selected ligands [17][18][19][20] or the aim of creating and exploring hitherto unusual Si coordination compounds, e.g., with transition metals [21][22][23][24][25][26][27][28][29] or very soft Lewis bases in their ligand sphere [30][31][32][33][34][35][36][37][38], silicon coordination chemistry continues to be an attractive research field, reflected by frequently published research articles [39][40]…”