Contributions to the Chemistry of Boron, LXXV The Crystal and Molecular Structure of a Tetraazadiborine: 3,6-Bis(dimethylamino)-1,2,4,5-tetramethyl-1,2,4,5,3,6-tetraazadiborine
Abstract:X-ray, Bis(dimethylamino)-tetramethyl-tetraazadiborineThe title compound crystallizes in the monoclinic system with dimensions of the unit cell a = 14.09(2), b = 8.60(1), c = 11.34(1) A and ß = 101.7The space group was determined to be A 2/a with four molecules in the unit cell.
“…Hence, the double bond character of the former appears to be much more pronounced. The structural features of the hydrazine moiety, i.e., the N−N bond length [1.425(2) Å] and the distorted trigonal-planar environment of the nitrogen atoms [114.7(2)−128.5(2)°; N1, N2: Σ = 360°] as well as the torsion angle B1−N3−N4−B2 = −107.0(2)°, are comparable to those found in the related species [−B(NMe 2 )N(Me)N(Me)−] 2 or Mes 2 B(Ph)N−NH(Ph) and have been discussed in detail by Power and Nöth. , 1 Molecular structure of 4 . Selected bond lengths (Å) and angles (deg): Cr1−C Ph between 2.126(2) and 2.158(2), C11−B1 1.585(3), C21−B2 1.583(3), B1−N1 1.402(3), B2−N2 1.402(3), B1−N3 1.471(3), B2−N4 1.476(3), N3−N4 1.425(2), Cr1−X Ph1 1.603, Cr1−X Ph2 1.611; C11−B1−N3 119.8(2), C21−B2−N4 119.1(2), B1−N3−N4 117.2(2), B2−N4−N3 116.9(2), C31−N3−N4 114.7(2), C41−N4−N3 114.7(2), X Ph1 −Cr1−X Ph2 178.4, B1−N3−N4−C41 72.6(2), B1−N3−N4−B2 −107.0(2), B2−N4−N3−C31 71.9(2), C31−N3−N4−C41 −108.5(1), X Ph1 −C11−C21−X Ph2 −36.1, α 1.98(2) (X Ph1 = centroid of C11−C16, X Ph2 = centroid of C21−C26).…”
The diboration of the N=N double bond of azobenzene was achieved by reaction of the [3]diboraplatinametalloarenophanes derived from ferrocene, [Fe(eta5-C5H4)B(NMe2)Pt(PEt3)2B(NMe2)(eta5-C5H4)], and bis(benzene)chromium, [Cr(eta6-C6H5)B(NMe2)Pt(PEt3)2B(NMe2)(eta6-C6H5)], with an excess of azobenzene in toluene at elevated temperature. The formation of the anticipated ansa-bis(boryl)hydrazines was substantiated by the determination of the molecular structure of the chromium derivative by X-ray diffraction. The synthesis of the ansa-bis(boryl)hydrazine derivative of ferrocene could also be accomplished under homogeneous catalysis conditions. Hence, reaction of the well-known [2]boraferrocenophane, [Fe(eta5-C5H4)2B2(NMe2)2], and azobenzene in the presence of 5 mol % [Pt(PEt3)3] afforded the bis-borylated hydrazine derivative in good yields.
“…Hence, the double bond character of the former appears to be much more pronounced. The structural features of the hydrazine moiety, i.e., the N−N bond length [1.425(2) Å] and the distorted trigonal-planar environment of the nitrogen atoms [114.7(2)−128.5(2)°; N1, N2: Σ = 360°] as well as the torsion angle B1−N3−N4−B2 = −107.0(2)°, are comparable to those found in the related species [−B(NMe 2 )N(Me)N(Me)−] 2 or Mes 2 B(Ph)N−NH(Ph) and have been discussed in detail by Power and Nöth. , 1 Molecular structure of 4 . Selected bond lengths (Å) and angles (deg): Cr1−C Ph between 2.126(2) and 2.158(2), C11−B1 1.585(3), C21−B2 1.583(3), B1−N1 1.402(3), B2−N2 1.402(3), B1−N3 1.471(3), B2−N4 1.476(3), N3−N4 1.425(2), Cr1−X Ph1 1.603, Cr1−X Ph2 1.611; C11−B1−N3 119.8(2), C21−B2−N4 119.1(2), B1−N3−N4 117.2(2), B2−N4−N3 116.9(2), C31−N3−N4 114.7(2), C41−N4−N3 114.7(2), X Ph1 −Cr1−X Ph2 178.4, B1−N3−N4−C41 72.6(2), B1−N3−N4−B2 −107.0(2), B2−N4−N3−C31 71.9(2), C31−N3−N4−C41 −108.5(1), X Ph1 −C11−C21−X Ph2 −36.1, α 1.98(2) (X Ph1 = centroid of C11−C16, X Ph2 = centroid of C21−C26).…”
The diboration of the N=N double bond of azobenzene was achieved by reaction of the [3]diboraplatinametalloarenophanes derived from ferrocene, [Fe(eta5-C5H4)B(NMe2)Pt(PEt3)2B(NMe2)(eta5-C5H4)], and bis(benzene)chromium, [Cr(eta6-C6H5)B(NMe2)Pt(PEt3)2B(NMe2)(eta6-C6H5)], with an excess of azobenzene in toluene at elevated temperature. The formation of the anticipated ansa-bis(boryl)hydrazines was substantiated by the determination of the molecular structure of the chromium derivative by X-ray diffraction. The synthesis of the ansa-bis(boryl)hydrazine derivative of ferrocene could also be accomplished under homogeneous catalysis conditions. Hence, reaction of the well-known [2]boraferrocenophane, [Fe(eta5-C5H4)2B2(NMe2)2], and azobenzene in the presence of 5 mol % [Pt(PEt3)3] afforded the bis-borylated hydrazine derivative in good yields.
“…Dieser Dipol tntt unter den milden Reaktionsbedingungen sicher nicht frei auf, wird aber von Dipolarophilen unter Cycloaddition dann leicht abgefangen, wenn sich ein 671-Elektronensystem ausbilden kann; dies ist bei den hier beschriebenen Reaktionen rnit Heterocumulenen der Fall, aber auch bei zahlreichen weiteren Systemen, uber die wir noch berichten werden. .73910(33) 1.25187 (28) .507U2 ( 12) .51707 ( 8) .~.RoI ( 8) .40804 (12) .39782( U) 449111 8) , 563061 12) .48963 (13) .34523(10) ,43536111) .56273 (11] .55685 (12] .60510 (15] .66015 (15) .66758 (13) .51978 ( 11) .35231 (11) .30681 (11] .25722 (13) .25112 (13) 34412112)…”
Several monomeric dimethylaluminium hydrazide ether adducts Et2O/THF × Me2AlNR–NR′R′′ (5–7) were obtained by deprotonating the respective hydrazines with nBuLi, followed by reaction with Me2AlCl. The hydrazines Ph(H)N–N(SiMe3)2 and tBu(H)N–N(H)SiMe3 react with LiAlH4 in the presence of either ether or THF with the formation of dimeric lithium hydrazino(hydrido)aluminates, e.g. 8 and 9. Their structures depend on the number of acidic hydrogen atoms bonded to the nitrogen atoms of the starting hydrazine. The hydrazine Ph(H)N–N(SiMe3)2 (1) reacts with LiAlH4 to form monometallated LiAlH3[(Ph)N–N(SiMe3)2] × 2 Et2O (8) with elimination of one equivalent of H2. The molecule is dimeric and features an (AlHLiH)2 eight‐membered ring. In contrast, the reaction of tBu(H)N–N(H)SiMe3 with LiAlH4 in the presence of THF leads to the formation of dimeric 2 THF × LiAlH2[(tBu)N–N(SiMe3)] (9) with a central (AlNN)2 six‐membered ring. A dimeric aluminium hydrazide 10 was obtained by allowing tBu(Li)N–N(H)SiMe3 to react with Me2AlCl in a hexane/toluene solution. The structure of 10 features a six‐membered Al2N4 ring in chair conformation.
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