Increasing Molecular Planarity through Donor/Side-Chain Engineering for Improved NIR-IIa Fluorescence Imaging and NIR-II Photothermal Therapy under 1064 nm

Developing conjugated small molecules (CSM) with intense NIR-II (1000–1700 nm) absorption for phototheranostic is highly desirable but remains a tremendous challenge due to a lack of reliable design guidelines. This study reports a high-performance NIR-II CSM for phototheranostic by tailoring molecular planarity. A series of CSM show bathochromic absorption extended to the NIR-II region upon the increasing thiophene number, but an excessive number of thiophene results in decreased NIR-IIa (1300–1400 nm) brightness and photothermal effects. Further introduction of terminal nonconjugated alkyl chain can enhance NIR-II absorption coefficient, NIR-IIa brightness, and photothermal effects. Mechanism studies ascribe this overall enhancement to molecular planarity stemming from the collective contribution of donor/side-chain engineering. This finding directs the design of NIR-II CSM by rational manipulating molecular planarity to perform 1064 nm mediated phototheranostic at high efficiency.     

Unit Graphs Associated with Rings

Let R be a ring with nonzero identity. The unit graph of R, denoted by G(R), has its set of vertices equal to the set of all elements of R; distinct vertices x and y are adjacent if and only if x + y is a unit of R. In this article, the basic properties of G(R) are investigated and some characterization results regarding connectedness, chromatic index, diameter, girth, and planarity of G(R) are given. (These terms are defined in Definitions and Remarks 4.1, 5.1, 5.3, 5.9, and 5.13.)     

Out-of-plane deformation of the azulene ring in crystal structures of simply substituted azulene derivatives

The crystal structures of 1,3-bis(4-bromophenyl)- and 1,3-di(2-thienyl)azulenes (5 and 6) were elucidated by X-ray analysis. Two aryl groups connect to the azulenyl core with dihedral angles of 34.9-41.6° and the two aryl planes of the groups slant against the azulene ring toward different ways in their crystal structures. It was also found that the azulene rings of 5 and 6 showed a slight out-of-plane deformation in the way that the hydrogen atoms at the 4- and 8-positions are apart from the neighboring aryl ortho-hydrogen atoms to fill in the vacant space made by the slanting aryl planes.     

On embedding a cycle in a plane graph

Consider a planar drawing Γ of a planar graph G such that the vertices are drawn as small circles and the edges are drawn as thin stripes. Consider a non-simple cycle c of G. Is it possible to draw c as a non-intersecting closed curve inside Γ, following the circles that correspond in Γ to the vertices of c and the stripes that connect them? We show that this test can be done in polynomial time and study this problem in the framework of clustered planarity for highly non-connected clustered graphs.     

On maximum planar induced subgraphs

The nonplanar vertex deletion or vertex deletion vd(G) of a graph G is the smallest nonnegative integer k, such that the removal of k vertices from G produces a planar graph G^′. In this case G^′ is said to be a maximum planar induced subgraph of G. We solve a problem proposed by Yannakakis: find the threshold for the maximum degree of a graph G such that, given a graph G and a nonnegative integer k, to decide whether vd(G)?k is NP-complete. We prove that it is NP-complete to decide whether a maximum degree 3 graph G and a nonnegative integer k satisfy vd(G)?k. We prove that unless P=NP there is no polynomial-time approximation algorithm with fixed ratio to compute the size of a maximum planar induced subgraph for graphs in general. We prove that it is Max SNP-hard to compute vd(G) when restricted to a cubic input G. Finally, we exhibit a polynomial-time -approximation algorithm for finding a maximum planar induced subgraph of a maximum degree 3 graph.     

About intrinsic errors of optical planarity measurements

We analyze the errors of optical 3D area sensors in measuring geometric parameters, taking planarity as our example. If the planarity of the surface is comparable to the repeat accuracy, the measured planarity is in general unduly poor and the object appears less planar. This error manifests itself to the observer as an apparently systematic offset. This error arises from the interplay of typical properties of optical sensors with standardized methods of interpretation. The standardized interpretation methods for planarity require the use of the maximum departures of the measured heights from the fitted (reference) plane. Optical area sensors can yield very large values for this maximum deviation, even when the standard deviation is small, because these sensors measure up to a million points at a time. The probability of a large maximum error is much lower when the measurement is done on a few points, as it usually is with mechanical sensors. As a consequence, the qualification of optical 3D area sensors calls for a correction with respect to mechanical sensors. In this article, we use methods of extreme-value statistics to determine the errors that occur. Once the error is known, the measured results can be corrected and incorporated into known and standardized methods of interpretation.     

4-[4-(2-吡啶基)苯乙烯基]-N,N-二正丁基苯胺的合成、晶体结构及光学性质

合成了具有D-π-A型结构的含吡啶基的新型有机化合物4-[4-(2-吡啶基)苯乙烯基]-N,N-二正丁基苯胺,其结构经元素分析、UV和X射线衍射进行了表征。 利用单光子液体荧光光谱、单光子荧光量子产率、固体荧光光谱和荧光寿命探讨了它的光学性质。 该分子晶体属于三斜晶系,P-1空间群, 晶胞参数为：a=1.150 41(3) nm,b=1.457 46(4) nm,c=1.515 98(4) nm,Z=4,V=2.330 68(11) nm3,R1=0.096 2,wR2=0.263 0。 通过研究发现,目标化合物平面性好,分子为D-π-A型结构,分子间有C-H…π相互作用,使得它具有良好的光学性质。     

激光间接驱动冲击波实验测量

 在神光Ⅱ高功率激光装置上,利用光学条纹相机观测台阶靶背面的冲击波加热发光,对样品中冲击波的平面性和冲击波速度进行了测量。通过冲击波法测得的腔内辐射温度与软X光能谱仪的测量结果一致,验证了冲击波速度测量的可信度。实验结果表明：在8路能量各为260 J、波长为351 nm的激光注入腔靶时,激光间接驱动的冲击波阵面在288 mm范围内平面性较好,Al样品中的冲击波速度为3.15×10⁶ cm/s,对应的冲击波压力为1.66×10¹² Pa。     

Planarity of Cayley graphs of graph products of groups

We obtain a complete classification of graph products of finite abelian groups whose Cayley graphs with respect to the standard presentations are planar.     

Diborane Concatenation Leads to New Planar Boron Chemistry

Diborane has long been realized to be analogous to ethylene in terms of its bonding MOs, both as to symmetries and splitting patterns. This naturally suggests an investigation to see whether other similar conjugated hydrocarbons manifest a similar boron-substituted and H₂ supplemented borane. That is, for a conjugated hydrocarbon structure with a neighbor-paired resonance pattern, we propose to look at boranes where each carbon atom is replaced by a boron atom, and an H-atom pair is added to each double bond of the resonance structure, with one H above the molecular plane and one below. This construction of concatenated diboranes is uniformly different than that for the previously known stable boranes of 4 or more B atoms. We find from quantum-chemical computations that our so constructed polyboranes are stable. All this suggests a possible novel new chapter in borane chemistry – a chapter with some promise of understandings related to that for (alternant) conjugated hydrocarbons.