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Five structures of Ge2H2 and Ge2H2+ are investigated in this study. Optimized geometries at the CCSD(T)/cc-pwCVQZ-PP level of theory were obtained. Focal point analyses were performed on these optimized geometries to determine relative energies using the CCSD(T) method with polarized basis sets up to quintuple-zeta. Energy corrections include full T and pertubative (Q) coupled-cluster effects plus anharmonic corrections to the zero-point vibrational energy. Relative ordering in energy from lowest to highest of the five Ge2H2+ structures is butterfly, germylidene, monobridged, trans, then linear. In neutral Ge2H2, the monobridged structure lies lower in energy than the germylidene structure. Fundamental vibrational frequencies and IR intensities were computed for the minima at the CCSD(T)/cc-pwCVTZ-PP level of theory to compare with experimental research. Partial atomic charges and natural bonding orbital analyses indicated that the positive charge of Ge2H2+ is contained in the region of the Ge–Ge bond. [ABSTRACT FROM AUTHOR]

While the dithiolene-based N-heterocyclic silane (4) reacts with two equivalents of BX3 (X = Br, I) to give zwitterionic Lewis adducts 5 and 8, respectively, the parallel reaction of 4 with BCl3 results in 10, a dithiolene-substituted N-heterocyclic silane, via the Si-S bond cleavage. Unlike 5, the labile 8 may be readily converted to 9 via BI3-mediated cleavage of the Si-N bond. The formation of 5 and 8 confirms that 4 uniquely possesses dual nucleophilic sites: (a) the terminal sulphur atom of the dithiolene moiety; and (b) the backbone carbon of the N-heterocyclic silane unit. [ABSTRACT FROM AUTHOR]

While the 1 : 1 reaction of 3 with an N-heterocyclic carbene ({(Me)CN(i-Pr)}2C:) in THF resulted in ligand-substituted product 4, the corresponding 1 : 2 reaction (in the presence of H2O) gives the first structurally characterized germanium tris(dithiolene)dianion 5 as the major product and the "naked" dithiolene radical 6˙ as a minor by-product. The structure and bonding of 4 and 5 were probed by experimental and theoretical methods. Our study suggests that carbene-mediated partial hydrolysis may represent a new method to access tris(dithiolene) complexes of main-group elements. [ABSTRACT FROM AUTHOR]

The redox chemistry of the first stable anionic dithiolene radical 1Ṗ was investigated by both reactivity and cyclic voltammetry studies. While one-electron reduction of 1Ṗ by Cp2Co or KC8 affords the corresponding dithiolate dimers 2 and 3, respectively, one-electron oxidation of 1Ṗ by Ph3C+BF4− (or O2) conveniently gives 4, the neutral dithiolene dimer. [ABSTRACT FROM AUTHOR]

Reaction of 2-bromo-1,3,2-diazaborole (1) with excess BBr3 induces 1,2-hydrogen migration, giving 1,3,2-diazaborole-derived carbene complexes of boron bromide (2). Compound 2 exists in a dynamic solution equilibrium with 1. The 1H NMR study shows that the equilibrium lies to the right side of the dissociation reaction of 2. Parallel reaction of 1 with excess BI3 gives the corresponding 1,3,2-diazaborole-derived carbene boron iodide complex (3). Notably, in contrast to 2, the dissociation reaction of 3 largely lies to the left side, favouring the formation of 3. The dynamic solution equilibrium behaviours of 2 and 3 are probed by both experimental and theoretical methods. [ABSTRACT FROM AUTHOR]

While the 1 : 1 reaction of C4-trichlorosilyl-functionalized N-heterocyclic carbene (NHC) (2) with [(η5-C5H4Li)2Fe]3[TMEDA]2 (3) gives C4-sila[1]ferrocenophane-substituted NHC (4), C4-ferrocenylsilyl-bridged bis-NHC (6) is synthesized by combining 3 with C4-chlorodimethylsilyl-functionalized NHC (5) in a 1 : 2 ratio, (compound 5 is prepared by reaction of the anionic N-heterocyclic dicarbene (NHDC) [:C{[N(2,6-Pri2C6H3)]2CHCLi}]n (1) with Me2SiCl2). In addition, ligand 4- and 6-based GeCl2 complexes (7 and 8) are also synthesized. Compounds 4–8 have been characterized by 1H, 13C, and 29Si NMR spectroscopy and single crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

The first magnesium-based dithiolene, 2, was prepared by reaction of the lithium dithiolene radical, 1Ṗ, with 2-mesitylmagnesium bromide. Reaction of 2 with N-heterocyclic carbenes (in toluene) gave a carbene-stabilized magnesium monodithiolene complex, 3. Complex 3, in turn, is readily converted to a THF-solvated magnesium bis-dithiolene dianion, 4, via partial hydrolysis in polar solvents (i.e., THF/CH3CN). Compounds 2, 3 and 4 have been spectroscopically and structurally characterized and probed by DFT computations. [ABSTRACT FROM AUTHOR]

Reaction of the anionic N-heterocyclic dicarbene (NHDC), [:C{[N(2,6-Pri2C6H3)]2CHCLi}]n (1), with SiCl4 gives the trichlorosilyl-substituted (at the C4 carbon) N-heterocyclic carbene complex (7). Abnormal carbene–SiCl4 complex (8) may be conveniently synthesized by combining 7 with HCl·NEt3. In addition, 7 may react with CH2Cl2 in warm hexane, giving the abnormal carbene-complexed SiCl3+ cation (9). The nature of the bonding in 9 was probed with complementary DFT computations. [ABSTRACT FROM AUTHOR]

Low temperature reaction of N-heterocyclic carbene : BEt3 with nBuLi (in THF) initially gives the C4-lithiated N-heterocyclic carbene : BEt3 complex (4), which isomerizes to the C2-lithiated abnormal N-heterocyclic carbene : BEt3 complex (2) in refluxing THF. While reaction of 2 with GaCl3 gives a 4-functionalized N-heterocyclic carbene : GaCl3 adduct (6), reaction of 4 with GaCl3 affords the first abnormal carbene-gallium chloride complexes (5). [ABSTRACT FROM AUTHOR]

Reaction of carbene-stabilized diphosphorus, L:P–P:L (5) (L: = :C{N(2,6-Pri2C6H3)CH}2) with pyridine hydrochloride yields [L:(H)P–P:L]Cl (6), a salt containing the HP2+ cation―the elusive phosphorus analogue of the well known diazonium cation, HN2+. In addition to reporting the synthesis and structure, the nature of (6) was further probed by DFT computations. Interestingly, carbenes may be employed to deprotonate (6), affording the starting material (5). [ABSTRACT FROM AUTHOR]

Significant progress in the chemistry of main group compounds (group 13, 14, and 15) containing homonuclear multiple bonds has been made over the past three decades. This feature article addresses the unique structural and bonding motifs of these compounds, with a particular emphasis on both iconic molecules and recent novel discoveries. [ABSTRACT FROM AUTHOR]

Significant progress in the chemistry of main group compounds (group 13, 14, and 15) containing homonuclear multiple bonds has been made over the past three decades. This feature article addresses the unique structural and bonding motifs of these compounds, with a particular emphasis on both iconic molecules and recent novel discoveries. [ABSTRACT FROM AUTHOR]

Reaction of carbene-stabilized diphosphorus, L:P–P:L (L: = :C{N(2,6-Pri2C6H3)CH}2, 1), with excess BH3·THF affords the boronium salt [L:P(μ-BH2)P:L]+[B2H7]−, 2, which contains a three-membered P2B ring. When 2is dissolved in THF, compounds 1and 2exist in a dynamic solution equilibrium. [ABSTRACT FROM AUTHOR]

Reaction of carbene-stabilized diphosphorus, L:P–P:L (5) (L: = :C{N(2,6-Pri2C6H3)CH}2) with pyridine hydrochloride yields [L:(H)P–P:L]Cl (6), a salt containing the HP2+ cation―the elusive phosphorus analogue of the well known diazonium cation, HN2+. In addition to reporting the synthesis and structure, the nature of (6) was further probed by DFT computations. Interestingly, carbenes may be employed to deprotonate (6), affording the starting material (5). [ABSTRACT FROM AUTHOR]

Five structures of Ge 2 H 2 and Ge 2 H 2 + are investigated in this study. Optimized geometries at the CCSD(T)/cc-pwCVQZ-PP level of theory were obtained. Focal point analyses were performed on these optimized geometries to determine relative energies using the CCSD(T) method with polarized basis sets up to quintuple-zeta. Energy corrections include full T and pertubative (Q) coupled-cluster effects plus anharmonic corrections to the zero-point vibrational energy. Relative ordering in energy from lowest to highest of the five Ge 2 H 2 + structures is butterfly, germylidene, monobridged, trans , then linear. In neutral Ge 2 H 2 , the monobridged structure lies lower in energy than the germylidene structure. Fundamental vibrational frequencies and IR intensities were computed for the minima at the CCSD(T)/cc-pwCVTZ-PP level of theory to compare with experimental research. Partial atomic charges and natural bonding orbital analyses indicated that the positive charge of Ge 2 H 2 + is contained in the region of the Ge-Ge bond.

While the dithiolene-based N-heterocyclic silane (4) reacts with two equivalents of BX 3 (X = Br, I) to give zwitterionic Lewis adducts 5 and 8, respectively, the parallel reaction of 4 with BCl 3 results in 10, a dithiolene-substituted N-heterocyclic silane, via the Si-S bond cleavage. Unlike 5, the labile 8 may be readily converted to 9 via BI 3 -mediated cleavage of the Si-N bond. The formation of 5 and 8 confirms that 4 uniquely possesses dual nucleophilic sites: (a) the terminal sulphur atom of the dithiolene moiety; and (b) the backbone carbon of the N-heterocyclic silane unit.

The redox chemistry of the first stable anionic dithiolene radical 1˙ was investigated by both reactivity and cyclic voltammetry studies. While one-electron reduction of 1˙ by Cp2Co or KC8 affords the corresponding dithiolate dimers 2 and 3, respectively, one-electron oxidation of 1˙ by Ph3C+BF4- (or O2) conveniently gives 4, the neutral dithiolene dimer.

Reaction of 2-bromo-1,3,2-diazaborole (1) with excess BBr 3 induces 1,2-hydrogen migration, giving 1,3,2-diazaborole-derived carbene complexes of boron bromide (2). Compound 2 exists in a dynamic solution equilibrium with 1. The 1 H NMR study shows that the equilibrium lies to the right side of the dissociation reaction of 2. Parallel reaction of 1 with excess BI 3 gives the corresponding 1,3,2-diazaborole-derived carbene boron iodide complex (3). Notably, in contrast to 2, the dissociation reaction of 3 largely lies to the left side, favouring the formation of 3. The dynamic solution equilibrium behaviours of 2 and 3 are probed by both experimental and theoretical methods.

While the 1 : 1 reaction of C4-trichlorosilyl-functionalized N-heterocyclic carbene (NHC) (2) with [(η 5 -C 5 H 4 Li) 2 Fe] 3 [TMEDA] 2 (3) gives C4-sila[1]ferrocenophane-substituted NHC (4), C4-ferrocenylsilyl-bridged bis-NHC (6) is synthesized by combining 3 with C4-chlorodimethylsilyl-functionalized NHC (5) in a 1 : 2 ratio, (compound 5 is prepared by reaction of the anionic N-heterocyclic dicarbene (NHDC) [:C{[N(2,6-Pr i 2 C 6 H 3 )] 2 CHCLi}] n (1) with Me 2 SiCl 2 ). In addition, ligand 4- and 6-based GeCl 2 complexes (7 and 8) are also synthesized. Compounds 4-8 have been characterized by 1 H, 13 C, and 29 Si NMR spectroscopy and single crystal X-ray diffraction.

Reaction of carbene-stabilized diphosphorus, L:P-P:L (5) (L: = :C{N(2,6-Pr(i)2C6H3)CH}2) with pyridine hydrochloride yields [L:(H)P-P:L]Cl (6), a salt containing the HP2(+) cation--the elusive phosphorus analogue of the well known diazonium cation, HN2(+). In addition to reporting the synthesis and structure, the nature of (6) was further probed by DFT computations. Interestingly, carbenes may be employed to deprotonate (6), affording the starting material (5).

Reaction of the anionic N-heterocyclic dicarbene (NHDC), [:C{[N(2,6-Pr(i)2C6H3)]2CHCLi}]n (1), with SiCl4 gives the trichlorosilyl-substituted (at the C4 carbon) N-heterocyclic carbene complex (7). Abnormal carbene-SiCl4 complex (8) may be conveniently synthesized by combining 7 with HCl·NEt3. In addition, 7 may react with CH2Cl2 in warm hexane, giving the abnormal carbene-complexed SiCl3(+) cation (9). The nature of the bonding in 9 was probed with complementary DFT computations.

Low temperature reaction of N-heterocyclic carbene : BEt3 with nBuLi (in THF) initially gives the C4-lithiated N-heterocyclic carbene : BEt3 complex (4), which isomerizes to the C2-lithiated abnormal N-heterocyclic carbene : BEt3 complex (2) in refluxing THF. While reaction of with GaCl3 gives a 4-functionalized N-heterocyclic carbene : GaCl3 adduct (6), reaction of with GaCl3 affords the first abnormal carbene-gallium chloride complexes (5).

While transition metals are well known for assuming the formal oxidation state of zero in various compounds main group elements have rarely engaged in this practice. Recent reports of N-heterocyclic carbene-stabilized main group diatomic allotropes (i.e., Si(2), Ge(2), P(2), As(2)) denote a breakthrough of zero-oxidation state main group chemistry. This Perspective addresses the synthesis and characterization of these highly reactive main group molecules, with a particular emphasis on the very recent progress in the reactivity study of carbene-stabilized Si(2) and P(2).

Reaction of RLi with lead(II) bromide affords the diaryl lead(II) compounds PbR2 (R1 = 2,4,6-triphenylphenyl, 1; R2 = 2,6-bis(1'-naphthyl)phenyl, 2), which have monomeric, carbene-like structures with bent two-coordinate Pb(II) centers.

Reaction of lead(II) chloride with biphenylmagnesium bromide yields Bp(3)Pb-PbBp(3) and [(THF)(3)Mg(mu-Cl)(3)Mg(THF)(3)][Pb(PbBp(3))(3)](Bp = biphenyl), which, upon single crystal X-ray crystallographic analysis, reveals an interesting variation of Pb-Pb bond distances.