With inspirations from recent discoveries of the cage-like borospherene B₄₀ and perfectly planar Co ∈ B₁₈^- and based on extensive global minimum searches and first-principles theory calculations, we present herein the possibility of the novel planar Ni ∈ B₁₈ (1), cage-like heteroborospherenes Ni_n ∈ B₄₀ (n = 1-4) (2-5), and planar heteroborophenes Ni₂ ∈ B₁₄ (6, 7) which all contain planar or quasi-planar heptacoordinate transition-metal (phTM) centers in η⁷-B₇ heptagons. The nearly degenerate Ni₂ ∈ B₁₄ (6) and Ni₂ ∈ B₁₄ (7) monolayers are predicted to be metallic in nature, with Ni₂ ∈ B₁₄ (6) composed of interwoven boron double chains with two phNi centers per unit cell being the precursor of cage-like Ni_n ∈ B₄₀ (n = 1-4) (2-5). Detailed bonding analyses indicate that Ni_n ∈ B₄₀ (n = 1-4) (2-5) and Ni₂ ∈ B₁₄ (6, 7) possess the universal bonding pattern of σ + π double delocalization on the boron frameworks, with each phNi forming three lone pairs in radial direction (3d_z2², 3d_zx², and 3d_yz²) and two effective nearly in-plane 8c-2e σ-coordination bonds between the remaining tangential Ni 3d orbitals (3d_x2-y2 and 3d_xy) and the η⁷-B₇ heptagon around it. The IR, Raman, and UV-vis absorption spectra of 1-5 are computationally simulated to facilitate their experimental characterizations.

中文翻译：

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杂硼球团簇Nin∈B40（n = 1-4），杂硼烷单层Ni2∈B14在η7-B7七边形中具有平面七坐标过渡金属中心。

随着从最近的笼状硼球烯B的发现启示₄₀和完美的平面共∈乙₁₈ ^-和基于广泛的全局最小值的搜索和第一原理的理论计算中，我们提出的新的平面的本文中的可能性的Ni∈乙₁₈（1 ），笼状heteroborospherenes镍_ñ  ∈乙₄₀（N = 1-4）（2-5），以及平面heteroborophenes的Ni ₂  ∈乙₁₄（6,7），其都包含平面或准平面heptacoordinate过渡金属（ phTM）在η中心^7个-B ₇七边形。近简并的Ni ₂  ∈乙₁₄（6）和Ni ₂  ∈乙₁₄（7）单层被预测为金属性质的，用Ni ₂  ∈乙₁₄（6），每个单元电池2个phNi中心为笼状-Ni的前体交织硼双链组成_Ñ  ∈乙₄₀（N = 1-4）（2-5）。详细接合分析表明，镍_ñ  ∈乙₄₀（N = 1-4）（2-5）和Ni ₂  ∈乙₁₄（6,7）具有σ+π离域双重的普遍粘合图案上的硼的框架，用每个phNi形成在径向方向上的三个孤对（3D _Z2 ²，三维_ZX ²和3d _YZ ²）和两个有效近平面8C-2Eσ配位的剩余切线镍之间的键3d轨道（3D _X2-Y2和3d_的xy）和η ⁷ -B ₇周围七边形。通过计算机模拟1-5的红外，拉曼和紫外可见吸收光谱，以方便其实验表征。