Anomalous reactions of the diamine Me2NCH2NMe2 with nickel(ii) and cobalt(ii)

Hitchcock, Peter B.; Handley, Darren A; Lee, Ting Huei; Leigh, G.J.

doi:10.1039/b207818j

Cited by 11 publications

(10 citation statements)

References 8 publications

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“…The 3D lattice structure is held together by hydrogen bonds of the type CH ⋅⋅⋅ OC ranging from 2.593(5) to 2.827(5) Å. This structure is similar to three triamine complexes described in the literature, that is, CoCl 2 [(Me 2 NCH 2 ) 2 NMe], and [Co(CO) 4 CuNMe 2 ) 2 NR (R=H and propyl), together with a similar biuret iridium complex, Ir(NH−CO−NH−CO−NH), both involving bidentate structural motif …”

Section: Figuresupporting

confidence: 56%

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)₄] Complexes

Sharma

Gonzalez

Craig

et al. 2016

Chemistry A European J

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Compound Et3 SiOCH2 NMe2 transfers Me2 NCH2 to R2 NH (R2 =Et2 , PhMe, [Cr(η(6) -C6 H5 )(CO)3 ]Me, PhH) to form previously unknown diaminomethanes, Me2 NCH2 NR2 and, in the case of R2 =PhH, the triamine Me2 NCH2 N(Ph)CH2 NMe2 . The diaminomethanes exhibit an unreported disproportionation to a mixture of (R2 N)2 CH2 , (Me2 N)2 CH2 , and Me2 NCH2 NR2 , which can be trapped as their [Mo(CO)4 (diamine)] complexes. Whereas PhMeNCH2 NMe2 is a labile material, the metal-substituted ([(η(6) -C6 H5 )Cr(CO)3 ]MeNCH2 NMe2 is a stable material. The triamine Me2 NCH2 N(Ph)CH2 NMe2 is unstable with respect to transformation to 1,3,5-triphenyltriazine, but is readily trapped as the bidentate-triamineMo(CO)4 . All metal complexes were characterized by single-crystal X-ray diffraction.

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Section: Figuresupporting

confidence: 56%

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)₄] Complexes

Sharma

Gonzalez

Craig

et al. 2016

Chemistry A European J

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“…Denks group reported the X-ray crystal structure of carbene tBu5 [17] and the corresponding formamidinium thiocyanate. [56] In the complex 11, comprising iPr6 and KN(SiMe 3 ) 2 , [25] the carbene is coordinated to the potassium ion through a bond 3.00 in length that is surely mainly electrostatic in nature. [50] A number of structures contain the tetramethylformamidinium ion; in Table 1 data is shown for the salt (Me 2 N) 2 CH·[(H 2 C(NMe 2 ) 2 )NiCl 3 ].…”

Section: Structures For Diaminocarbenes Me5-ipra and Their Dimersmentioning

confidence: 99%

“…[50] A number of structures contain the tetramethylformamidinium ion; in Table 1 data is shown for the salt (Me 2 N) 2 CH·[(H 2 C(NMe 2 ) 2 )NiCl 3 ]. [56] In the complex 11, comprising iPr6 and KN(SiMe 3 ) 2 , [25] the carbene is coordinated to the potassium ion through a bond 3.00 in length that is surely mainly electrostatic in nature. The calculated bond lengths and angles for iPr6 agree with those for the carbene moieties in the complex.…”

Section: Structures For Diaminocarbenes Me5-ipra and Their Dimersmentioning

confidence: 99%

When and How Do Diaminocarbenes Dimerize?

et al. 2004

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No example of a simple uncatalyzed dimerization of a diaminocarbene has been clearly established, so it is timely to ask what factors control the thermodynamics of this reaction, and what mechanisms are responsible for the observed dimerizations? In agreement with qualitative experimental observations, the dimerizations of simple five- and six-membered-ring diaminocarbenes are calculated to be 100 kJ mol(-1) less favorable than those of acyclic counterparts. This large difference is semiquantitatively accounted for by bond and torsional angle changes around the carbene centers. Carbenes such as (Et(2)N)(2)C are kinetically stable in THF at 25 degrees C in agreement with calculated energy barriers, but they rapidly dimerize in the presence of the corresponding formamidinium ion. This proton-catalyzed process is probably the most common mechanism for dimer formation, and involves formation of C-protonated dimers, which can be observed in suitable cases. The possibility of alkali-metal-promoted dimerization is raised, and circumstantial evidence for this is presented.

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“…Eine Reihe von Strukturen enthalten das Tetramethylformamidiniumion. Die Daten für das Salz (Me 2 N) 2 CH⋅[(H 2 C(NMe 2 ) 2 )NiCl 3 ]56 sind in Tabelle 1 angegeben.…”

Section: Strukturen Der Diaminocarbene Me5–ipra Und Ihrer Dimereunclassified

Wann und wie dimerisieren Diaminocarbene?

et al. 2004

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Bisher wurde kein eindeutiger Nachweis für eine einfache, nicht katalysierte Dimerisierung von Diaminocarbenen gefunden. Es ist somit an der Zeit zu hinterfragen, welche Faktoren die Thermodynamik dieser Reaktion steuern und welche Mechanismen für die beobachteten Dimerisierungen verantwortlich sind. In Übereinstimmung mit qualitativen experimentellen Beobachtungen ergab die Berechnung, dass die Dimerisierung von einfachen Fünf‐ und Sechsringdiaminocarbenen um 100 kJ mol−1 weniger begünstigt ist als die der acyclischen Pendants. Dieser große Unterschied kann halbquantitativ durch die Änderung von Bindungs‐ und Torsionswinkeln um die Carbenzentren herum erklärt werden. Carbene wie (Et2N)2C sind, in Einklang mit den berechneten Energiebarrieren, in THF bei 25 °C kinetisch stabil, aber sie dimerisieren schnell in Gegenwart des entsprechenden Formamidiniumions. Dieser protonenkatalysierte Prozess ist wahrscheinlich der häufigste Mechanismus der Dimerbildung. Er führt zur Bildung von C‐protonierten Dimeren, was in geeigneten Fällen beobachtet werden kann. Es wird auch die Möglichkeit der durch Alkalimetalle geförderten Dimerisierung diskutiert; hierfür werden einige Belege vorgestellt.

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Anomalous reactions of the diamine Me2NCH2NMe2 with nickel(ii) and cobalt(ii)

Cited by 11 publications

References 8 publications

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)₄] Complexes

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)₄] Complexes

When and How Do Diaminocarbenes Dimerize?

Wann und wie dimerisieren Diaminocarbene?

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Anomalous reactions of the diamine Me2NCH2NMe2 with nickel(ii) and cobalt(ii)

Cited by 11 publications

References 8 publications

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)4] Complexes

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)4] Complexes

When and How Do Diaminocarbenes Dimerize?

Wann und wie dimerisieren Diaminocarbene?

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Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)₄] Complexes

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)₄] Complexes